2007-06-12 13:07:21 +00:00
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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2007-07-11 14:00:37 +00:00
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#include <linux/sched.h>
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2007-12-21 21:27:24 +00:00
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#include <linux/pagemap.h>
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2008-04-28 19:29:52 +00:00
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#include <linux/writeback.h>
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2008-08-12 13:13:26 +00:00
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#include <linux/blkdev.h>
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2009-02-04 14:23:45 +00:00
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#include <linux/sort.h>
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2009-03-10 16:39:20 +00:00
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#include <linux/rcupdate.h>
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Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
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#include <linux/kthread.h>
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include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
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#include <linux/slab.h>
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2008-11-20 15:22:27 +00:00
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#include "compat.h"
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2007-12-11 14:25:06 +00:00
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#include "hash.h"
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2007-02-26 15:40:21 +00:00
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#include "ctree.h"
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#include "disk-io.h"
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#include "print-tree.h"
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2007-03-16 20:20:31 +00:00
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#include "transaction.h"
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2008-03-24 19:01:56 +00:00
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#include "volumes.h"
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2008-06-25 20:01:30 +00:00
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#include "locking.h"
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2009-04-03 13:47:43 +00:00
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#include "free-space-cache.h"
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2007-02-26 15:40:21 +00:00
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2008-11-12 19:19:50 +00:00
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static int update_block_group(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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2010-05-16 14:46:25 +00:00
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u64 bytenr, u64 num_bytes, int alloc);
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static int update_reserved_bytes(struct btrfs_block_group_cache *cache,
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u64 num_bytes, int reserve, int sinfo);
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Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
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static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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u64 bytenr, u64 num_bytes, u64 parent,
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u64 root_objectid, u64 owner_objectid,
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u64 owner_offset, int refs_to_drop,
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struct btrfs_delayed_extent_op *extra_op);
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static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
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struct extent_buffer *leaf,
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struct btrfs_extent_item *ei);
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static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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u64 parent, u64 root_objectid,
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u64 flags, u64 owner, u64 offset,
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struct btrfs_key *ins, int ref_mod);
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static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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u64 parent, u64 root_objectid,
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u64 flags, struct btrfs_disk_key *key,
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int level, struct btrfs_key *ins);
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2009-02-20 16:00:09 +00:00
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static int do_chunk_alloc(struct btrfs_trans_handle *trans,
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struct btrfs_root *extent_root, u64 alloc_bytes,
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u64 flags, int force);
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2009-09-11 20:11:19 +00:00
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static int find_next_key(struct btrfs_path *path, int level,
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struct btrfs_key *key);
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2009-09-11 20:12:44 +00:00
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static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
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int dump_block_groups);
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2009-02-20 16:00:09 +00:00
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Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
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static noinline int
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block_group_cache_done(struct btrfs_block_group_cache *cache)
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{
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smp_mb();
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return cache->cached == BTRFS_CACHE_FINISHED;
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}
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|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
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static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
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{
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return (cache->flags & bits) == bits;
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}
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2009-11-13 20:12:59 +00:00
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void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
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{
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atomic_inc(&cache->count);
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}
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void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
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{
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2010-05-16 14:46:25 +00:00
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if (atomic_dec_and_test(&cache->count)) {
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WARN_ON(cache->pinned > 0);
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WARN_ON(cache->reserved > 0);
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WARN_ON(cache->reserved_pinned > 0);
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2009-11-13 20:12:59 +00:00
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kfree(cache);
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2010-05-16 14:46:25 +00:00
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}
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2009-11-13 20:12:59 +00:00
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}
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|
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Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
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/*
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* this adds the block group to the fs_info rb tree for the block group
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* cache
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*/
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2008-12-02 14:54:17 +00:00
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static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
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struct btrfs_block_group_cache *block_group)
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{
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struct rb_node **p;
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struct rb_node *parent = NULL;
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struct btrfs_block_group_cache *cache;
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spin_lock(&info->block_group_cache_lock);
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p = &info->block_group_cache_tree.rb_node;
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while (*p) {
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parent = *p;
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cache = rb_entry(parent, struct btrfs_block_group_cache,
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cache_node);
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if (block_group->key.objectid < cache->key.objectid) {
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p = &(*p)->rb_left;
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} else if (block_group->key.objectid > cache->key.objectid) {
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p = &(*p)->rb_right;
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} else {
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spin_unlock(&info->block_group_cache_lock);
|
|
|
|
return -EEXIST;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
rb_link_node(&block_group->cache_node, parent, p);
|
|
|
|
rb_insert_color(&block_group->cache_node,
|
|
|
|
&info->block_group_cache_tree);
|
|
|
|
spin_unlock(&info->block_group_cache_lock);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This will return the block group at or after bytenr if contains is 0, else
|
|
|
|
* it will return the block group that contains the bytenr
|
|
|
|
*/
|
|
|
|
static struct btrfs_block_group_cache *
|
|
|
|
block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
|
|
|
|
int contains)
|
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *cache, *ret = NULL;
|
|
|
|
struct rb_node *n;
|
|
|
|
u64 end, start;
|
|
|
|
|
|
|
|
spin_lock(&info->block_group_cache_lock);
|
|
|
|
n = info->block_group_cache_tree.rb_node;
|
|
|
|
|
|
|
|
while (n) {
|
|
|
|
cache = rb_entry(n, struct btrfs_block_group_cache,
|
|
|
|
cache_node);
|
|
|
|
end = cache->key.objectid + cache->key.offset - 1;
|
|
|
|
start = cache->key.objectid;
|
|
|
|
|
|
|
|
if (bytenr < start) {
|
|
|
|
if (!contains && (!ret || start < ret->key.objectid))
|
|
|
|
ret = cache;
|
|
|
|
n = n->rb_left;
|
|
|
|
} else if (bytenr > start) {
|
|
|
|
if (contains && bytenr <= end) {
|
|
|
|
ret = cache;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
n = n->rb_right;
|
|
|
|
} else {
|
|
|
|
ret = cache;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
2008-12-11 21:30:39 +00:00
|
|
|
if (ret)
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_get_block_group(ret);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
spin_unlock(&info->block_group_cache_lock);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
static int add_excluded_extent(struct btrfs_root *root,
|
|
|
|
u64 start, u64 num_bytes)
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
{
|
2009-09-11 20:11:19 +00:00
|
|
|
u64 end = start + num_bytes - 1;
|
|
|
|
set_extent_bits(&root->fs_info->freed_extents[0],
|
|
|
|
start, end, EXTENT_UPTODATE, GFP_NOFS);
|
|
|
|
set_extent_bits(&root->fs_info->freed_extents[1],
|
|
|
|
start, end, EXTENT_UPTODATE, GFP_NOFS);
|
|
|
|
return 0;
|
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
static void free_excluded_extents(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
u64 start, end;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
start = cache->key.objectid;
|
|
|
|
end = start + cache->key.offset - 1;
|
|
|
|
|
|
|
|
clear_extent_bits(&root->fs_info->freed_extents[0],
|
|
|
|
start, end, EXTENT_UPTODATE, GFP_NOFS);
|
|
|
|
clear_extent_bits(&root->fs_info->freed_extents[1],
|
|
|
|
start, end, EXTENT_UPTODATE, GFP_NOFS);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
static int exclude_super_stripes(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
{
|
|
|
|
u64 bytenr;
|
|
|
|
u64 *logical;
|
|
|
|
int stripe_len;
|
|
|
|
int i, nr, ret;
|
|
|
|
|
2009-11-26 09:31:11 +00:00
|
|
|
if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
|
|
|
|
stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
|
|
|
|
cache->bytes_super += stripe_len;
|
|
|
|
ret = add_excluded_extent(root, cache->key.objectid,
|
|
|
|
stripe_len);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
|
|
|
|
bytenr = btrfs_sb_offset(i);
|
|
|
|
ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
|
|
|
|
cache->key.objectid, bytenr,
|
|
|
|
0, &logical, &nr, &stripe_len);
|
|
|
|
BUG_ON(ret);
|
2009-09-11 20:11:19 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
while (nr--) {
|
2009-09-11 20:11:20 +00:00
|
|
|
cache->bytes_super += stripe_len;
|
2009-09-11 20:11:19 +00:00
|
|
|
ret = add_excluded_extent(root, logical[nr],
|
|
|
|
stripe_len);
|
|
|
|
BUG_ON(ret);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
2009-09-11 20:11:19 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
kfree(logical);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
static struct btrfs_caching_control *
|
|
|
|
get_caching_control(struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
struct btrfs_caching_control *ctl;
|
|
|
|
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (cache->cached != BTRFS_CACHE_STARTED) {
|
|
|
|
spin_unlock(&cache->lock);
|
2010-09-16 20:17:03 +00:00
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* We're loading it the fast way, so we don't have a caching_ctl. */
|
|
|
|
if (!cache->caching_ctl) {
|
|
|
|
spin_unlock(&cache->lock);
|
2009-09-11 20:11:19 +00:00
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
ctl = cache->caching_ctl;
|
|
|
|
atomic_inc(&ctl->count);
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
return ctl;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void put_caching_control(struct btrfs_caching_control *ctl)
|
|
|
|
{
|
|
|
|
if (atomic_dec_and_test(&ctl->count))
|
|
|
|
kfree(ctl);
|
|
|
|
}
|
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
/*
|
|
|
|
* this is only called by cache_block_group, since we could have freed extents
|
|
|
|
* we need to check the pinned_extents for any extents that can't be used yet
|
|
|
|
* since their free space will be released as soon as the transaction commits.
|
|
|
|
*/
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_fs_info *info, u64 start, u64 end)
|
|
|
|
{
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
u64 extent_start, extent_end, size, total_added = 0;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
int ret;
|
|
|
|
|
|
|
|
while (start < end) {
|
2009-09-11 20:11:19 +00:00
|
|
|
ret = find_first_extent_bit(info->pinned_extents, start,
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
&extent_start, &extent_end,
|
2009-09-11 20:11:19 +00:00
|
|
|
EXTENT_DIRTY | EXTENT_UPTODATE);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
if (ret)
|
|
|
|
break;
|
|
|
|
|
2009-11-26 09:31:11 +00:00
|
|
|
if (extent_start <= start) {
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
start = extent_end + 1;
|
|
|
|
} else if (extent_start > start && extent_start < end) {
|
|
|
|
size = extent_start - start;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
total_added += size;
|
2008-11-20 17:16:16 +00:00
|
|
|
ret = btrfs_add_free_space(block_group, start,
|
|
|
|
size);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
start = extent_end + 1;
|
|
|
|
} else {
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (start < end) {
|
|
|
|
size = end - start;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
total_added += size;
|
2008-11-20 17:16:16 +00:00
|
|
|
ret = btrfs_add_free_space(block_group, start, size);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
return total_added;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
static int caching_kthread(void *data)
|
2007-05-10 00:13:14 +00:00
|
|
|
{
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
struct btrfs_block_group_cache *block_group = data;
|
|
|
|
struct btrfs_fs_info *fs_info = block_group->fs_info;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control *caching_ctl = block_group->caching_ctl;
|
|
|
|
struct btrfs_root *extent_root = fs_info->extent_root;
|
2007-05-10 00:13:14 +00:00
|
|
|
struct btrfs_path *path;
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *leaf;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_key key;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
u64 total_found = 0;
|
2009-09-11 20:11:19 +00:00
|
|
|
u64 last = 0;
|
|
|
|
u32 nritems;
|
|
|
|
int ret = 0;
|
2007-10-15 20:14:48 +00:00
|
|
|
|
2007-05-10 00:13:14 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
2007-09-14 20:15:28 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
exclude_super_stripes(extent_root, block_group);
|
2009-09-11 20:11:20 +00:00
|
|
|
spin_lock(&block_group->space_info->lock);
|
2010-05-16 14:46:25 +00:00
|
|
|
block_group->space_info->bytes_readonly += block_group->bytes_super;
|
2009-09-11 20:11:20 +00:00
|
|
|
spin_unlock(&block_group->space_info->lock);
|
2009-09-11 20:11:19 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
|
2009-09-11 20:11:19 +00:00
|
|
|
|
2008-06-25 20:01:30 +00:00
|
|
|
/*
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
* We don't want to deadlock with somebody trying to allocate a new
|
|
|
|
* extent for the extent root while also trying to search the extent
|
|
|
|
* root to add free space. So we skip locking and search the commit
|
|
|
|
* root, since its read-only
|
2008-06-25 20:01:30 +00:00
|
|
|
*/
|
|
|
|
path->skip_locking = 1;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
path->search_commit_root = 1;
|
|
|
|
path->reada = 2;
|
|
|
|
|
2008-12-12 15:03:26 +00:00
|
|
|
key.objectid = last;
|
2007-05-10 00:13:14 +00:00
|
|
|
key.offset = 0;
|
2009-09-11 20:11:19 +00:00
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
2009-07-31 18:57:55 +00:00
|
|
|
again:
|
2009-09-11 20:11:19 +00:00
|
|
|
mutex_lock(&caching_ctl->mutex);
|
2009-07-31 18:57:55 +00:00
|
|
|
/* need to make sure the commit_root doesn't disappear */
|
|
|
|
down_read(&fs_info->extent_commit_sem);
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
|
2007-05-10 00:13:14 +00:00
|
|
|
if (ret < 0)
|
2008-09-23 17:14:11 +00:00
|
|
|
goto err;
|
2008-12-08 21:46:26 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (1) {
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
smp_mb();
|
2009-09-11 20:11:19 +00:00
|
|
|
if (fs_info->closing > 1) {
|
2009-07-28 12:41:57 +00:00
|
|
|
last = (u64)-1;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
break;
|
2009-07-28 12:41:57 +00:00
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
if (path->slots[0] < nritems) {
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
} else {
|
|
|
|
ret = find_next_key(path, 0, &key);
|
|
|
|
if (ret)
|
2007-05-10 00:13:14 +00:00
|
|
|
break;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
caching_ctl->progress = last;
|
|
|
|
btrfs_release_path(extent_root, path);
|
|
|
|
up_read(&fs_info->extent_commit_sem);
|
|
|
|
mutex_unlock(&caching_ctl->mutex);
|
|
|
|
if (btrfs_transaction_in_commit(fs_info))
|
2009-07-30 14:04:48 +00:00
|
|
|
schedule_timeout(1);
|
2009-09-11 20:11:19 +00:00
|
|
|
else
|
|
|
|
cond_resched();
|
|
|
|
goto again;
|
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
if (key.objectid < block_group->key.objectid) {
|
|
|
|
path->slots[0]++;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
continue;
|
2007-05-10 00:13:14 +00:00
|
|
|
}
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2007-05-10 00:13:14 +00:00
|
|
|
if (key.objectid >= block_group->key.objectid +
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
block_group->key.offset)
|
2007-05-10 00:13:14 +00:00
|
|
|
break;
|
2007-09-14 20:15:28 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
if (key.type == BTRFS_EXTENT_ITEM_KEY) {
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
total_found += add_new_free_space(block_group,
|
|
|
|
fs_info, last,
|
|
|
|
key.objectid);
|
2007-09-14 20:15:28 +00:00
|
|
|
last = key.objectid + key.offset;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
if (total_found > (1024 * 1024 * 2)) {
|
|
|
|
total_found = 0;
|
|
|
|
wake_up(&caching_ctl->wait);
|
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
2007-05-10 00:13:14 +00:00
|
|
|
path->slots[0]++;
|
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
ret = 0;
|
2007-05-10 00:13:14 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
total_found += add_new_free_space(block_group, fs_info, last,
|
|
|
|
block_group->key.objectid +
|
|
|
|
block_group->key.offset);
|
2009-09-11 20:11:19 +00:00
|
|
|
caching_ctl->progress = (u64)-1;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
|
|
|
spin_lock(&block_group->lock);
|
2009-09-11 20:11:19 +00:00
|
|
|
block_group->caching_ctl = NULL;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
block_group->cached = BTRFS_CACHE_FINISHED;
|
|
|
|
spin_unlock(&block_group->lock);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2007-06-22 18:16:25 +00:00
|
|
|
err:
|
2007-05-10 00:13:14 +00:00
|
|
|
btrfs_free_path(path);
|
2009-07-30 13:40:40 +00:00
|
|
|
up_read(&fs_info->extent_commit_sem);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
free_excluded_extents(extent_root, block_group);
|
|
|
|
|
|
|
|
mutex_unlock(&caching_ctl->mutex);
|
|
|
|
wake_up(&caching_ctl->wait);
|
|
|
|
|
|
|
|
put_caching_control(caching_ctl);
|
|
|
|
atomic_dec(&block_group->space_info->caching_threads);
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-08-25 20:54:15 +00:00
|
|
|
static int cache_block_group(struct btrfs_block_group_cache *cache,
|
|
|
|
struct btrfs_trans_handle *trans,
|
2010-12-08 14:15:11 +00:00
|
|
|
struct btrfs_root *root,
|
2010-08-25 20:54:15 +00:00
|
|
|
int load_cache_only)
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
{
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_fs_info *fs_info = cache->fs_info;
|
|
|
|
struct btrfs_caching_control *caching_ctl;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
struct task_struct *tsk;
|
|
|
|
int ret = 0;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
smp_mb();
|
|
|
|
if (cache->cached != BTRFS_CACHE_NO)
|
|
|
|
return 0;
|
|
|
|
|
2010-08-25 20:54:15 +00:00
|
|
|
/*
|
|
|
|
* We can't do the read from on-disk cache during a commit since we need
|
2010-12-08 14:15:11 +00:00
|
|
|
* to have the normal tree locking. Also if we are currently trying to
|
|
|
|
* allocate blocks for the tree root we can't do the fast caching since
|
|
|
|
* we likely hold important locks.
|
2010-08-25 20:54:15 +00:00
|
|
|
*/
|
2010-12-08 14:15:11 +00:00
|
|
|
if (!trans->transaction->in_commit &&
|
|
|
|
(root && root != root->fs_info->tree_root)) {
|
2010-08-25 20:54:15 +00:00
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (cache->cached != BTRFS_CACHE_NO) {
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
cache->cached = BTRFS_CACHE_STARTED;
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
|
|
|
|
ret = load_free_space_cache(fs_info, cache);
|
|
|
|
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (ret == 1) {
|
|
|
|
cache->cached = BTRFS_CACHE_FINISHED;
|
|
|
|
cache->last_byte_to_unpin = (u64)-1;
|
|
|
|
} else {
|
|
|
|
cache->cached = BTRFS_CACHE_NO;
|
|
|
|
}
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
if (ret == 1)
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (load_cache_only)
|
|
|
|
return 0;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
|
|
|
|
BUG_ON(!caching_ctl);
|
|
|
|
|
|
|
|
INIT_LIST_HEAD(&caching_ctl->list);
|
|
|
|
mutex_init(&caching_ctl->mutex);
|
|
|
|
init_waitqueue_head(&caching_ctl->wait);
|
|
|
|
caching_ctl->block_group = cache;
|
|
|
|
caching_ctl->progress = cache->key.objectid;
|
|
|
|
/* one for caching kthread, one for caching block group list */
|
|
|
|
atomic_set(&caching_ctl->count, 2);
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (cache->cached != BTRFS_CACHE_NO) {
|
|
|
|
spin_unlock(&cache->lock);
|
2009-09-11 20:11:19 +00:00
|
|
|
kfree(caching_ctl);
|
|
|
|
return 0;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
2009-09-11 20:11:19 +00:00
|
|
|
cache->caching_ctl = caching_ctl;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->cached = BTRFS_CACHE_STARTED;
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
down_write(&fs_info->extent_commit_sem);
|
|
|
|
list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
|
|
|
|
up_write(&fs_info->extent_commit_sem);
|
|
|
|
|
|
|
|
atomic_inc(&cache->space_info->caching_threads);
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_get_block_group(cache);
|
2009-09-11 20:11:19 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
tsk = kthread_run(caching_kthread, cache, "btrfs-cache-%llu\n",
|
|
|
|
cache->key.objectid);
|
|
|
|
if (IS_ERR(tsk)) {
|
|
|
|
ret = PTR_ERR(tsk);
|
|
|
|
printk(KERN_ERR "error running thread %d\n", ret);
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
|
2008-09-23 17:14:11 +00:00
|
|
|
return ret;
|
2007-05-10 00:13:14 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
/*
|
|
|
|
* return the block group that starts at or after bytenr
|
|
|
|
*/
|
2009-01-06 02:25:51 +00:00
|
|
|
static struct btrfs_block_group_cache *
|
|
|
|
btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
|
2008-05-24 18:04:53 +00:00
|
|
|
{
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_block_group_cache *cache;
|
2008-05-24 18:04:53 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
cache = block_group_cache_tree_search(info, bytenr, 0);
|
2008-05-24 18:04:53 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
return cache;
|
2008-05-24 18:04:53 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
/*
|
2009-05-14 17:52:22 +00:00
|
|
|
* return the block group that contains the given bytenr
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
*/
|
2009-01-06 02:25:51 +00:00
|
|
|
struct btrfs_block_group_cache *btrfs_lookup_block_group(
|
|
|
|
struct btrfs_fs_info *info,
|
|
|
|
u64 bytenr)
|
2007-05-06 14:15:01 +00:00
|
|
|
{
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_block_group_cache *cache;
|
2007-05-06 14:15:01 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
cache = block_group_cache_tree_search(info, bytenr, 1);
|
2007-10-15 20:15:19 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
return cache;
|
2007-05-06 14:15:01 +00:00
|
|
|
}
|
2008-03-24 19:01:56 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
|
|
|
|
u64 flags)
|
2008-03-24 19:01:59 +00:00
|
|
|
{
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct list_head *head = &info->space_info;
|
|
|
|
struct btrfs_space_info *found;
|
2009-03-10 16:39:20 +00:00
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
|
|
|
|
BTRFS_BLOCK_GROUP_METADATA;
|
|
|
|
|
2009-03-10 16:39:20 +00:00
|
|
|
rcu_read_lock();
|
|
|
|
list_for_each_entry_rcu(found, head, list) {
|
2010-09-16 20:19:09 +00:00
|
|
|
if (found->flags & flags) {
|
2009-03-10 16:39:20 +00:00
|
|
|
rcu_read_unlock();
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
return found;
|
2009-03-10 16:39:20 +00:00
|
|
|
}
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
}
|
2009-03-10 16:39:20 +00:00
|
|
|
rcu_read_unlock();
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
return NULL;
|
2008-03-24 19:01:59 +00:00
|
|
|
}
|
|
|
|
|
2009-03-10 16:39:20 +00:00
|
|
|
/*
|
|
|
|
* after adding space to the filesystem, we need to clear the full flags
|
|
|
|
* on all the space infos.
|
|
|
|
*/
|
|
|
|
void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
|
|
|
|
{
|
|
|
|
struct list_head *head = &info->space_info;
|
|
|
|
struct btrfs_space_info *found;
|
|
|
|
|
|
|
|
rcu_read_lock();
|
|
|
|
list_for_each_entry_rcu(found, head, list)
|
|
|
|
found->full = 0;
|
|
|
|
rcu_read_unlock();
|
|
|
|
}
|
|
|
|
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
static u64 div_factor(u64 num, int factor)
|
|
|
|
{
|
|
|
|
if (factor == 10)
|
|
|
|
return num;
|
|
|
|
num *= factor;
|
|
|
|
do_div(num, 10);
|
|
|
|
return num;
|
|
|
|
}
|
|
|
|
|
2010-10-26 17:37:56 +00:00
|
|
|
static u64 div_factor_fine(u64 num, int factor)
|
|
|
|
{
|
|
|
|
if (factor == 100)
|
|
|
|
return num;
|
|
|
|
num *= factor;
|
|
|
|
do_div(num, 100);
|
|
|
|
return num;
|
|
|
|
}
|
|
|
|
|
2008-12-11 21:30:39 +00:00
|
|
|
u64 btrfs_find_block_group(struct btrfs_root *root,
|
|
|
|
u64 search_start, u64 search_hint, int owner)
|
2007-04-27 14:08:34 +00:00
|
|
|
{
|
2007-10-15 20:15:19 +00:00
|
|
|
struct btrfs_block_group_cache *cache;
|
2007-04-27 14:08:34 +00:00
|
|
|
u64 used;
|
2008-12-11 21:30:39 +00:00
|
|
|
u64 last = max(search_hint, search_start);
|
|
|
|
u64 group_start = 0;
|
2007-04-30 19:25:45 +00:00
|
|
|
int full_search = 0;
|
2008-12-11 21:30:39 +00:00
|
|
|
int factor = 9;
|
2008-05-24 18:04:53 +00:00
|
|
|
int wrapped = 0;
|
2007-04-30 19:25:45 +00:00
|
|
|
again:
|
2008-09-26 14:05:48 +00:00
|
|
|
while (1) {
|
|
|
|
cache = btrfs_lookup_first_block_group(root->fs_info, last);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
if (!cache)
|
|
|
|
break;
|
2007-10-15 20:15:19 +00:00
|
|
|
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_lock(&cache->lock);
|
2007-10-15 20:15:19 +00:00
|
|
|
last = cache->key.objectid + cache->key.offset;
|
|
|
|
used = btrfs_block_group_used(&cache->item);
|
|
|
|
|
2008-12-11 21:30:39 +00:00
|
|
|
if ((full_search || !cache->ro) &&
|
|
|
|
block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
|
2008-09-26 14:05:48 +00:00
|
|
|
if (used + cache->pinned + cache->reserved <
|
2008-12-11 21:30:39 +00:00
|
|
|
div_factor(cache->key.offset, factor)) {
|
|
|
|
group_start = cache->key.objectid;
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_unlock(&cache->lock);
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(cache);
|
2008-04-03 20:29:03 +00:00
|
|
|
goto found;
|
|
|
|
}
|
2008-03-24 19:01:59 +00:00
|
|
|
}
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_unlock(&cache->lock);
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(cache);
|
2007-05-18 17:28:27 +00:00
|
|
|
cond_resched();
|
2007-04-27 14:08:34 +00:00
|
|
|
}
|
2008-05-24 18:04:53 +00:00
|
|
|
if (!wrapped) {
|
|
|
|
last = search_start;
|
|
|
|
wrapped = 1;
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
if (!full_search && factor < 10) {
|
2007-05-06 14:15:01 +00:00
|
|
|
last = search_start;
|
2007-04-30 19:25:45 +00:00
|
|
|
full_search = 1;
|
2008-05-24 18:04:53 +00:00
|
|
|
factor = 10;
|
2007-04-30 19:25:45 +00:00
|
|
|
goto again;
|
|
|
|
}
|
2007-05-06 14:15:01 +00:00
|
|
|
found:
|
2008-12-11 21:30:39 +00:00
|
|
|
return group_start;
|
2008-06-25 20:01:30 +00:00
|
|
|
}
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2008-09-05 20:13:11 +00:00
|
|
|
/* simple helper to search for an existing extent at a given offset */
|
2008-09-23 17:14:14 +00:00
|
|
|
int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
|
2008-09-05 20:13:11 +00:00
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
struct btrfs_key key;
|
2008-09-23 17:14:14 +00:00
|
|
|
struct btrfs_path *path;
|
2008-09-05 20:13:11 +00:00
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
2008-09-05 20:13:11 +00:00
|
|
|
key.objectid = start;
|
|
|
|
key.offset = len;
|
|
|
|
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
|
|
|
|
ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
|
|
|
|
0, 0);
|
2008-09-23 17:14:14 +00:00
|
|
|
btrfs_free_path(path);
|
2007-12-11 14:25:06 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
/*
|
|
|
|
* helper function to lookup reference count and flags of extent.
|
|
|
|
*
|
|
|
|
* the head node for delayed ref is used to store the sum of all the
|
|
|
|
* reference count modifications queued up in the rbtree. the head
|
|
|
|
* node may also store the extent flags to set. This way you can check
|
|
|
|
* to see what the reference count and extent flags would be if all of
|
|
|
|
* the delayed refs are not processed.
|
|
|
|
*/
|
|
|
|
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 bytenr,
|
|
|
|
u64 num_bytes, u64 *refs, u64 *flags)
|
|
|
|
{
|
|
|
|
struct btrfs_delayed_ref_head *head;
|
|
|
|
struct btrfs_delayed_ref_root *delayed_refs;
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct btrfs_extent_item *ei;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_key key;
|
|
|
|
u32 item_size;
|
|
|
|
u64 num_refs;
|
|
|
|
u64 extent_flags;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
key.objectid = bytenr;
|
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
key.offset = num_bytes;
|
|
|
|
if (!trans) {
|
|
|
|
path->skip_locking = 1;
|
|
|
|
path->search_commit_root = 1;
|
|
|
|
}
|
|
|
|
again:
|
|
|
|
ret = btrfs_search_slot(trans, root->fs_info->extent_root,
|
|
|
|
&key, path, 0, 0);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out_free;
|
|
|
|
|
|
|
|
if (ret == 0) {
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
if (item_size >= sizeof(*ei)) {
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_item);
|
|
|
|
num_refs = btrfs_extent_refs(leaf, ei);
|
|
|
|
extent_flags = btrfs_extent_flags(leaf, ei);
|
|
|
|
} else {
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
struct btrfs_extent_item_v0 *ei0;
|
|
|
|
BUG_ON(item_size != sizeof(*ei0));
|
|
|
|
ei0 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_item_v0);
|
|
|
|
num_refs = btrfs_extent_refs_v0(leaf, ei0);
|
|
|
|
/* FIXME: this isn't correct for data */
|
|
|
|
extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
|
|
|
#else
|
|
|
|
BUG();
|
|
|
|
#endif
|
|
|
|
}
|
|
|
|
BUG_ON(num_refs == 0);
|
|
|
|
} else {
|
|
|
|
num_refs = 0;
|
|
|
|
extent_flags = 0;
|
|
|
|
ret = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!trans)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
|
|
spin_lock(&delayed_refs->lock);
|
|
|
|
head = btrfs_find_delayed_ref_head(trans, bytenr);
|
|
|
|
if (head) {
|
|
|
|
if (!mutex_trylock(&head->mutex)) {
|
|
|
|
atomic_inc(&head->node.refs);
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
|
|
|
|
btrfs_release_path(root->fs_info->extent_root, path);
|
|
|
|
|
|
|
|
mutex_lock(&head->mutex);
|
|
|
|
mutex_unlock(&head->mutex);
|
|
|
|
btrfs_put_delayed_ref(&head->node);
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
if (head->extent_op && head->extent_op->update_flags)
|
|
|
|
extent_flags |= head->extent_op->flags_to_set;
|
|
|
|
else
|
|
|
|
BUG_ON(num_refs == 0);
|
|
|
|
|
|
|
|
num_refs += head->node.ref_mod;
|
|
|
|
mutex_unlock(&head->mutex);
|
|
|
|
}
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
out:
|
|
|
|
WARN_ON(num_refs == 0);
|
|
|
|
if (refs)
|
|
|
|
*refs = num_refs;
|
|
|
|
if (flags)
|
|
|
|
*flags = extent_flags;
|
|
|
|
out_free:
|
|
|
|
btrfs_free_path(path);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2007-12-11 17:42:00 +00:00
|
|
|
/*
|
|
|
|
* Back reference rules. Back refs have three main goals:
|
|
|
|
*
|
|
|
|
* 1) differentiate between all holders of references to an extent so that
|
|
|
|
* when a reference is dropped we can make sure it was a valid reference
|
|
|
|
* before freeing the extent.
|
|
|
|
*
|
|
|
|
* 2) Provide enough information to quickly find the holders of an extent
|
|
|
|
* if we notice a given block is corrupted or bad.
|
|
|
|
*
|
|
|
|
* 3) Make it easy to migrate blocks for FS shrinking or storage pool
|
|
|
|
* maintenance. This is actually the same as #2, but with a slightly
|
|
|
|
* different use case.
|
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* There are two kinds of back refs. The implicit back refs is optimized
|
|
|
|
* for pointers in non-shared tree blocks. For a given pointer in a block,
|
|
|
|
* back refs of this kind provide information about the block's owner tree
|
|
|
|
* and the pointer's key. These information allow us to find the block by
|
|
|
|
* b-tree searching. The full back refs is for pointers in tree blocks not
|
|
|
|
* referenced by their owner trees. The location of tree block is recorded
|
|
|
|
* in the back refs. Actually the full back refs is generic, and can be
|
|
|
|
* used in all cases the implicit back refs is used. The major shortcoming
|
|
|
|
* of the full back refs is its overhead. Every time a tree block gets
|
|
|
|
* COWed, we have to update back refs entry for all pointers in it.
|
|
|
|
*
|
|
|
|
* For a newly allocated tree block, we use implicit back refs for
|
|
|
|
* pointers in it. This means most tree related operations only involve
|
|
|
|
* implicit back refs. For a tree block created in old transaction, the
|
|
|
|
* only way to drop a reference to it is COW it. So we can detect the
|
|
|
|
* event that tree block loses its owner tree's reference and do the
|
|
|
|
* back refs conversion.
|
|
|
|
*
|
|
|
|
* When a tree block is COW'd through a tree, there are four cases:
|
|
|
|
*
|
|
|
|
* The reference count of the block is one and the tree is the block's
|
|
|
|
* owner tree. Nothing to do in this case.
|
|
|
|
*
|
|
|
|
* The reference count of the block is one and the tree is not the
|
|
|
|
* block's owner tree. In this case, full back refs is used for pointers
|
|
|
|
* in the block. Remove these full back refs, add implicit back refs for
|
|
|
|
* every pointers in the new block.
|
|
|
|
*
|
|
|
|
* The reference count of the block is greater than one and the tree is
|
|
|
|
* the block's owner tree. In this case, implicit back refs is used for
|
|
|
|
* pointers in the block. Add full back refs for every pointers in the
|
|
|
|
* block, increase lower level extents' reference counts. The original
|
|
|
|
* implicit back refs are entailed to the new block.
|
|
|
|
*
|
|
|
|
* The reference count of the block is greater than one and the tree is
|
|
|
|
* not the block's owner tree. Add implicit back refs for every pointer in
|
|
|
|
* the new block, increase lower level extents' reference count.
|
|
|
|
*
|
|
|
|
* Back Reference Key composing:
|
|
|
|
*
|
|
|
|
* The key objectid corresponds to the first byte in the extent,
|
|
|
|
* The key type is used to differentiate between types of back refs.
|
|
|
|
* There are different meanings of the key offset for different types
|
|
|
|
* of back refs.
|
|
|
|
*
|
2007-12-11 17:42:00 +00:00
|
|
|
* File extents can be referenced by:
|
|
|
|
*
|
|
|
|
* - multiple snapshots, subvolumes, or different generations in one subvol
|
2008-09-23 17:14:14 +00:00
|
|
|
* - different files inside a single subvolume
|
2007-12-11 17:42:00 +00:00
|
|
|
* - different offsets inside a file (bookend extents in file.c)
|
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* The extent ref structure for the implicit back refs has fields for:
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
|
|
|
* - Objectid of the subvolume root
|
|
|
|
* - objectid of the file holding the reference
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* - original offset in the file
|
|
|
|
* - how many bookend extents
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* The key offset for the implicit back refs is hash of the first
|
|
|
|
* three fields.
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* The extent ref structure for the full back refs has field for:
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* - number of pointers in the tree leaf
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* The key offset for the implicit back refs is the first byte of
|
|
|
|
* the tree leaf
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* When a file extent is allocated, The implicit back refs is used.
|
|
|
|
* the fields are filled in:
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* (root_key.objectid, inode objectid, offset in file, 1)
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* When a file extent is removed file truncation, we find the
|
|
|
|
* corresponding implicit back refs and check the following fields:
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* (btrfs_header_owner(leaf), inode objectid, offset in file)
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* Btree extents can be referenced by:
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* - Different subvolumes
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* Both the implicit back refs and the full back refs for tree blocks
|
|
|
|
* only consist of key. The key offset for the implicit back refs is
|
|
|
|
* objectid of block's owner tree. The key offset for the full back refs
|
|
|
|
* is the first byte of parent block.
|
2007-12-11 17:42:00 +00:00
|
|
|
*
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
* When implicit back refs is used, information about the lowest key and
|
|
|
|
* level of the tree block are required. These information are stored in
|
|
|
|
* tree block info structure.
|
2007-12-11 17:42:00 +00:00
|
|
|
*/
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 owner, u32 extra_size)
|
2007-12-11 14:25:06 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_extent_item *item;
|
|
|
|
struct btrfs_extent_item_v0 *ei0;
|
|
|
|
struct btrfs_extent_ref_v0 *ref0;
|
|
|
|
struct btrfs_tree_block_info *bi;
|
|
|
|
struct extent_buffer *leaf;
|
2007-12-11 14:25:06 +00:00
|
|
|
struct btrfs_key key;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_key found_key;
|
|
|
|
u32 new_size = sizeof(*item);
|
|
|
|
u64 refs;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
|
|
|
|
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
ei0 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_item_v0);
|
|
|
|
refs = btrfs_extent_refs_v0(leaf, ei0);
|
|
|
|
|
|
|
|
if (owner == (u64)-1) {
|
|
|
|
while (1) {
|
|
|
|
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
|
|
|
|
ret = btrfs_next_leaf(root, path);
|
|
|
|
if (ret < 0)
|
|
|
|
return ret;
|
|
|
|
BUG_ON(ret > 0);
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
}
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key,
|
|
|
|
path->slots[0]);
|
|
|
|
BUG_ON(key.objectid != found_key.objectid);
|
|
|
|
if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
|
|
|
|
path->slots[0]++;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
ref0 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_ref_v0);
|
|
|
|
owner = btrfs_ref_objectid_v0(leaf, ref0);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
|
|
|
|
if (owner < BTRFS_FIRST_FREE_OBJECTID)
|
|
|
|
new_size += sizeof(*bi);
|
|
|
|
|
|
|
|
new_size -= sizeof(*ei0);
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path,
|
|
|
|
new_size + extra_size, 1);
|
|
|
|
if (ret < 0)
|
|
|
|
return ret;
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
ret = btrfs_extend_item(trans, root, path, new_size);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
btrfs_set_extent_refs(leaf, item, refs);
|
|
|
|
/* FIXME: get real generation */
|
|
|
|
btrfs_set_extent_generation(leaf, item, 0);
|
|
|
|
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
btrfs_set_extent_flags(leaf, item,
|
|
|
|
BTRFS_EXTENT_FLAG_TREE_BLOCK |
|
|
|
|
BTRFS_BLOCK_FLAG_FULL_BACKREF);
|
|
|
|
bi = (struct btrfs_tree_block_info *)(item + 1);
|
|
|
|
/* FIXME: get first key of the block */
|
|
|
|
memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
|
|
|
|
btrfs_set_tree_block_level(leaf, bi, (int)owner);
|
|
|
|
} else {
|
|
|
|
btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
|
|
|
|
}
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
|
|
|
|
{
|
|
|
|
u32 high_crc = ~(u32)0;
|
|
|
|
u32 low_crc = ~(u32)0;
|
|
|
|
__le64 lenum;
|
|
|
|
|
|
|
|
lenum = cpu_to_le64(root_objectid);
|
2009-04-19 12:02:41 +00:00
|
|
|
high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
lenum = cpu_to_le64(owner);
|
2009-04-19 12:02:41 +00:00
|
|
|
low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
lenum = cpu_to_le64(offset);
|
2009-04-19 12:02:41 +00:00
|
|
|
low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
return ((u64)high_crc << 31) ^ (u64)low_crc;
|
|
|
|
}
|
|
|
|
|
|
|
|
static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
|
|
|
|
struct btrfs_extent_data_ref *ref)
|
|
|
|
{
|
|
|
|
return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
|
|
|
|
btrfs_extent_data_ref_objectid(leaf, ref),
|
|
|
|
btrfs_extent_data_ref_offset(leaf, ref));
|
|
|
|
}
|
|
|
|
|
|
|
|
static int match_extent_data_ref(struct extent_buffer *leaf,
|
|
|
|
struct btrfs_extent_data_ref *ref,
|
|
|
|
u64 root_objectid, u64 owner, u64 offset)
|
|
|
|
{
|
|
|
|
if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
|
|
|
|
btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
|
|
|
|
btrfs_extent_data_ref_offset(leaf, ref) != offset)
|
|
|
|
return 0;
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 bytenr, u64 parent,
|
|
|
|
u64 root_objectid,
|
|
|
|
u64 owner, u64 offset)
|
|
|
|
{
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_extent_data_ref *ref;
|
2008-09-23 17:14:14 +00:00
|
|
|
struct extent_buffer *leaf;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u32 nritems;
|
2007-12-11 14:25:06 +00:00
|
|
|
int ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int recow;
|
|
|
|
int err = -ENOENT;
|
2007-12-11 14:25:06 +00:00
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
key.objectid = bytenr;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (parent) {
|
|
|
|
key.type = BTRFS_SHARED_DATA_REF_KEY;
|
|
|
|
key.offset = parent;
|
|
|
|
} else {
|
|
|
|
key.type = BTRFS_EXTENT_DATA_REF_KEY;
|
|
|
|
key.offset = hash_extent_data_ref(root_objectid,
|
|
|
|
owner, offset);
|
|
|
|
}
|
|
|
|
again:
|
|
|
|
recow = 0;
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
|
|
|
goto fail;
|
|
|
|
}
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (parent) {
|
|
|
|
if (!ret)
|
|
|
|
return 0;
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
key.type = BTRFS_EXTENT_REF_V0_KEY;
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
if (!ret)
|
|
|
|
return 0;
|
|
|
|
#endif
|
|
|
|
goto fail;
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
while (1) {
|
|
|
|
if (path->slots[0] >= nritems) {
|
|
|
|
ret = btrfs_next_leaf(root, path);
|
|
|
|
if (ret < 0)
|
|
|
|
err = ret;
|
|
|
|
if (ret)
|
|
|
|
goto fail;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
recow = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
if (key.objectid != bytenr ||
|
|
|
|
key.type != BTRFS_EXTENT_DATA_REF_KEY)
|
|
|
|
goto fail;
|
|
|
|
|
|
|
|
ref = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_data_ref);
|
|
|
|
|
|
|
|
if (match_extent_data_ref(leaf, ref, root_objectid,
|
|
|
|
owner, offset)) {
|
|
|
|
if (recow) {
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
err = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
path->slots[0]++;
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
fail:
|
|
|
|
return err;
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 bytenr, u64 parent,
|
|
|
|
u64 root_objectid, u64 owner,
|
|
|
|
u64 offset, int refs_to_add)
|
2008-09-23 17:14:14 +00:00
|
|
|
{
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct extent_buffer *leaf;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u32 size;
|
2008-09-23 17:14:14 +00:00
|
|
|
u32 num_refs;
|
|
|
|
int ret;
|
2007-12-11 14:25:06 +00:00
|
|
|
|
|
|
|
key.objectid = bytenr;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (parent) {
|
|
|
|
key.type = BTRFS_SHARED_DATA_REF_KEY;
|
|
|
|
key.offset = parent;
|
|
|
|
size = sizeof(struct btrfs_shared_data_ref);
|
|
|
|
} else {
|
|
|
|
key.type = BTRFS_EXTENT_DATA_REF_KEY;
|
|
|
|
key.offset = hash_extent_data_ref(root_objectid,
|
|
|
|
owner, offset);
|
|
|
|
size = sizeof(struct btrfs_extent_data_ref);
|
|
|
|
}
|
2007-12-11 14:25:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret = btrfs_insert_empty_item(trans, root, path, &key, size);
|
|
|
|
if (ret && ret != -EEXIST)
|
|
|
|
goto fail;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
if (parent) {
|
|
|
|
struct btrfs_shared_data_ref *ref;
|
2008-09-23 17:14:14 +00:00
|
|
|
ref = btrfs_item_ptr(leaf, path->slots[0],
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_shared_data_ref);
|
|
|
|
if (ret == 0) {
|
|
|
|
btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
|
|
|
|
} else {
|
|
|
|
num_refs = btrfs_shared_data_ref_count(leaf, ref);
|
|
|
|
num_refs += refs_to_add;
|
|
|
|
btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} else {
|
|
|
|
struct btrfs_extent_data_ref *ref;
|
|
|
|
while (ret == -EEXIST) {
|
|
|
|
ref = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_data_ref);
|
|
|
|
if (match_extent_data_ref(leaf, ref, root_objectid,
|
|
|
|
owner, offset))
|
|
|
|
break;
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
key.offset++;
|
|
|
|
ret = btrfs_insert_empty_item(trans, root, path, &key,
|
|
|
|
size);
|
|
|
|
if (ret && ret != -EEXIST)
|
|
|
|
goto fail;
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
}
|
|
|
|
ref = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_data_ref);
|
|
|
|
if (ret == 0) {
|
|
|
|
btrfs_set_extent_data_ref_root(leaf, ref,
|
|
|
|
root_objectid);
|
|
|
|
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
|
|
|
|
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
|
|
|
|
btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
|
|
|
|
} else {
|
|
|
|
num_refs = btrfs_extent_data_ref_count(leaf, ref);
|
|
|
|
num_refs += refs_to_add;
|
|
|
|
btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
ret = 0;
|
|
|
|
fail:
|
2007-12-11 14:25:06 +00:00
|
|
|
btrfs_release_path(root, path);
|
|
|
|
return ret;
|
2007-12-11 14:25:06 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
int refs_to_drop)
|
2008-09-23 17:14:14 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_extent_data_ref *ref1 = NULL;
|
|
|
|
struct btrfs_shared_data_ref *ref2 = NULL;
|
2008-09-23 17:14:14 +00:00
|
|
|
struct extent_buffer *leaf;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u32 num_refs = 0;
|
2008-09-23 17:14:14 +00:00
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
|
|
|
|
if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
|
|
ref1 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_data_ref);
|
|
|
|
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
|
|
|
|
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
|
|
|
|
ref2 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_shared_data_ref);
|
|
|
|
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
} else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
|
|
|
|
struct btrfs_extent_ref_v0 *ref0;
|
|
|
|
ref0 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_ref_v0);
|
|
|
|
num_refs = btrfs_ref_count_v0(leaf, ref0);
|
|
|
|
#endif
|
|
|
|
} else {
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
BUG_ON(num_refs < refs_to_drop);
|
|
|
|
num_refs -= refs_to_drop;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
if (num_refs == 0) {
|
|
|
|
ret = btrfs_del_item(trans, root, path);
|
|
|
|
} else {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
|
|
|
|
btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
|
|
|
|
else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
|
|
|
|
btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
else {
|
|
|
|
struct btrfs_extent_ref_v0 *ref0;
|
|
|
|
ref0 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_ref_v0);
|
|
|
|
btrfs_set_ref_count_v0(leaf, ref0, num_refs);
|
|
|
|
}
|
|
|
|
#endif
|
2008-09-23 17:14:14 +00:00
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static noinline u32 extent_data_ref_count(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_extent_inline_ref *iref)
|
2008-11-20 02:17:22 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_key key;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_extent_data_ref *ref1;
|
|
|
|
struct btrfs_shared_data_ref *ref2;
|
|
|
|
u32 num_refs = 0;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
if (iref) {
|
|
|
|
if (btrfs_extent_inline_ref_type(leaf, iref) ==
|
|
|
|
BTRFS_EXTENT_DATA_REF_KEY) {
|
|
|
|
ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
|
|
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
|
|
|
|
} else {
|
|
|
|
ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
|
|
|
|
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
|
|
|
|
}
|
|
|
|
} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
|
|
ref1 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_data_ref);
|
|
|
|
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
|
|
|
|
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
|
|
|
|
ref2 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_shared_data_ref);
|
|
|
|
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
} else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
|
|
|
|
struct btrfs_extent_ref_v0 *ref0;
|
|
|
|
ref0 = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_ref_v0);
|
|
|
|
num_refs = btrfs_ref_count_v0(leaf, ref0);
|
2008-11-20 15:22:27 +00:00
|
|
|
#endif
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} else {
|
|
|
|
WARN_ON(1);
|
|
|
|
}
|
|
|
|
return num_refs;
|
|
|
|
}
|
2008-11-20 02:17:22 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 bytenr, u64 parent,
|
|
|
|
u64 root_objectid)
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_key key;
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
int ret;
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
key.objectid = bytenr;
|
|
|
|
if (parent) {
|
|
|
|
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
|
|
|
|
key.offset = parent;
|
|
|
|
} else {
|
|
|
|
key.type = BTRFS_TREE_BLOCK_REF_KEY;
|
|
|
|
key.offset = root_objectid;
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
|
|
|
|
if (ret > 0)
|
|
|
|
ret = -ENOENT;
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
if (ret == -ENOENT && parent) {
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
key.type = BTRFS_EXTENT_REF_V0_KEY;
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
|
|
|
|
if (ret > 0)
|
|
|
|
ret = -ENOENT;
|
|
|
|
}
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
#endif
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
return ret;
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 bytenr, u64 parent,
|
|
|
|
u64 root_objectid)
|
2008-09-23 17:14:14 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_key key;
|
2008-09-23 17:14:14 +00:00
|
|
|
int ret;
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
key.objectid = bytenr;
|
|
|
|
if (parent) {
|
|
|
|
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
|
|
|
|
key.offset = parent;
|
|
|
|
} else {
|
|
|
|
key.type = BTRFS_TREE_BLOCK_REF_KEY;
|
|
|
|
key.offset = root_objectid;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
|
|
|
|
btrfs_release_path(root, path);
|
2008-09-23 17:14:14 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static inline int extent_ref_type(u64 parent, u64 owner)
|
2008-09-23 17:14:14 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int type;
|
|
|
|
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
if (parent > 0)
|
|
|
|
type = BTRFS_SHARED_BLOCK_REF_KEY;
|
|
|
|
else
|
|
|
|
type = BTRFS_TREE_BLOCK_REF_KEY;
|
|
|
|
} else {
|
|
|
|
if (parent > 0)
|
|
|
|
type = BTRFS_SHARED_DATA_REF_KEY;
|
|
|
|
else
|
|
|
|
type = BTRFS_EXTENT_DATA_REF_KEY;
|
|
|
|
}
|
|
|
|
return type;
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
2009-03-13 14:10:06 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
static int find_next_key(struct btrfs_path *path, int level,
|
|
|
|
struct btrfs_key *key)
|
2009-03-13 14:10:06 +00:00
|
|
|
|
2007-03-02 21:08:05 +00:00
|
|
|
{
|
2009-06-28 01:07:35 +00:00
|
|
|
for (; level < BTRFS_MAX_LEVEL; level++) {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (!path->nodes[level])
|
|
|
|
break;
|
|
|
|
if (path->slots[level] + 1 >=
|
|
|
|
btrfs_header_nritems(path->nodes[level]))
|
|
|
|
continue;
|
|
|
|
if (level == 0)
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[level], key,
|
|
|
|
path->slots[level] + 1);
|
|
|
|
else
|
|
|
|
btrfs_node_key_to_cpu(path->nodes[level], key,
|
|
|
|
path->slots[level] + 1);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
return 1;
|
|
|
|
}
|
2007-03-07 16:50:24 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
/*
|
|
|
|
* look for inline back ref. if back ref is found, *ref_ret is set
|
|
|
|
* to the address of inline back ref, and 0 is returned.
|
|
|
|
*
|
|
|
|
* if back ref isn't found, *ref_ret is set to the address where it
|
|
|
|
* should be inserted, and -ENOENT is returned.
|
|
|
|
*
|
|
|
|
* if insert is true and there are too many inline back refs, the path
|
|
|
|
* points to the extent item, and -EAGAIN is returned.
|
|
|
|
*
|
|
|
|
* NOTE: inline back refs are ordered in the same way that back ref
|
|
|
|
* items in the tree are ordered.
|
|
|
|
*/
|
|
|
|
static noinline_for_stack
|
|
|
|
int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_extent_inline_ref **ref_ret,
|
|
|
|
u64 bytenr, u64 num_bytes,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
u64 owner, u64 offset, int insert)
|
|
|
|
{
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_extent_item *ei;
|
|
|
|
struct btrfs_extent_inline_ref *iref;
|
|
|
|
u64 flags;
|
|
|
|
u64 item_size;
|
|
|
|
unsigned long ptr;
|
|
|
|
unsigned long end;
|
|
|
|
int extra_size;
|
|
|
|
int type;
|
|
|
|
int want;
|
|
|
|
int ret;
|
|
|
|
int err = 0;
|
2007-08-09 00:17:12 +00:00
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
key.objectid = bytenr;
|
2008-09-23 17:14:14 +00:00
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
2009-03-13 14:10:06 +00:00
|
|
|
key.offset = num_bytes;
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
want = extent_ref_type(parent, owner);
|
|
|
|
if (insert) {
|
|
|
|
extra_size = btrfs_extent_inline_ref_size(want);
|
2009-06-11 12:51:10 +00:00
|
|
|
path->keep_locks = 1;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} else
|
|
|
|
extra_size = -1;
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
|
2009-03-13 15:00:37 +00:00
|
|
|
if (ret < 0) {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
err = ret;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
if (item_size < sizeof(*ei)) {
|
|
|
|
if (!insert) {
|
|
|
|
err = -ENOENT;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
ret = convert_extent_item_v0(trans, root, path, owner,
|
|
|
|
extra_size);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
BUG_ON(item_size < sizeof(*ei));
|
|
|
|
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
flags = btrfs_extent_flags(leaf, ei);
|
|
|
|
|
|
|
|
ptr = (unsigned long)(ei + 1);
|
|
|
|
end = (unsigned long)ei + item_size;
|
|
|
|
|
|
|
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
|
|
|
|
ptr += sizeof(struct btrfs_tree_block_info);
|
|
|
|
BUG_ON(ptr > end);
|
|
|
|
} else {
|
|
|
|
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
|
|
|
|
}
|
|
|
|
|
|
|
|
err = -ENOENT;
|
|
|
|
while (1) {
|
|
|
|
if (ptr >= end) {
|
|
|
|
WARN_ON(ptr > end);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)ptr;
|
|
|
|
type = btrfs_extent_inline_ref_type(leaf, iref);
|
|
|
|
if (want < type)
|
|
|
|
break;
|
|
|
|
if (want > type) {
|
|
|
|
ptr += btrfs_extent_inline_ref_size(type);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
|
|
struct btrfs_extent_data_ref *dref;
|
|
|
|
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
|
|
if (match_extent_data_ref(leaf, dref, root_objectid,
|
|
|
|
owner, offset)) {
|
|
|
|
err = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (hash_extent_data_ref_item(leaf, dref) <
|
|
|
|
hash_extent_data_ref(root_objectid, owner, offset))
|
|
|
|
break;
|
|
|
|
} else {
|
|
|
|
u64 ref_offset;
|
|
|
|
ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
|
|
|
|
if (parent > 0) {
|
|
|
|
if (parent == ref_offset) {
|
|
|
|
err = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (ref_offset < parent)
|
|
|
|
break;
|
|
|
|
} else {
|
|
|
|
if (root_objectid == ref_offset) {
|
|
|
|
err = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (ref_offset < root_objectid)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
ptr += btrfs_extent_inline_ref_size(type);
|
|
|
|
}
|
|
|
|
if (err == -ENOENT && insert) {
|
|
|
|
if (item_size + extra_size >=
|
|
|
|
BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
|
|
|
|
err = -EAGAIN;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* To add new inline back ref, we have to make sure
|
|
|
|
* there is no corresponding back ref item.
|
|
|
|
* For simplicity, we just do not add new inline back
|
|
|
|
* ref if there is any kind of item for this block
|
|
|
|
*/
|
2009-06-28 01:07:35 +00:00
|
|
|
if (find_next_key(path, 0, &key) == 0 &&
|
|
|
|
key.objectid == bytenr &&
|
2009-06-11 12:51:10 +00:00
|
|
|
key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
err = -EAGAIN;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
|
|
|
|
out:
|
2009-06-11 12:51:10 +00:00
|
|
|
if (insert) {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
path->keep_locks = 0;
|
|
|
|
btrfs_unlock_up_safe(path, 1);
|
|
|
|
}
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* helper to add new inline back ref
|
|
|
|
*/
|
|
|
|
static noinline_for_stack
|
|
|
|
int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_extent_inline_ref *iref,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
u64 owner, u64 offset, int refs_to_add,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op)
|
|
|
|
{
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_extent_item *ei;
|
|
|
|
unsigned long ptr;
|
|
|
|
unsigned long end;
|
|
|
|
unsigned long item_offset;
|
|
|
|
u64 refs;
|
|
|
|
int size;
|
|
|
|
int type;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
item_offset = (unsigned long)iref - (unsigned long)ei;
|
|
|
|
|
|
|
|
type = extent_ref_type(parent, owner);
|
|
|
|
size = btrfs_extent_inline_ref_size(type);
|
|
|
|
|
|
|
|
ret = btrfs_extend_item(trans, root, path, size);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
refs = btrfs_extent_refs(leaf, ei);
|
|
|
|
refs += refs_to_add;
|
|
|
|
btrfs_set_extent_refs(leaf, ei, refs);
|
|
|
|
if (extent_op)
|
|
|
|
__run_delayed_extent_op(extent_op, leaf, ei);
|
|
|
|
|
|
|
|
ptr = (unsigned long)ei + item_offset;
|
|
|
|
end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
if (ptr < end - size)
|
|
|
|
memmove_extent_buffer(leaf, ptr + size, ptr,
|
|
|
|
end - size - ptr);
|
|
|
|
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)ptr;
|
|
|
|
btrfs_set_extent_inline_ref_type(leaf, iref, type);
|
|
|
|
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
|
|
struct btrfs_extent_data_ref *dref;
|
|
|
|
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
|
|
btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
|
|
|
|
btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
|
|
|
|
btrfs_set_extent_data_ref_offset(leaf, dref, offset);
|
|
|
|
btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
|
|
|
|
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
|
|
|
|
struct btrfs_shared_data_ref *sref;
|
|
|
|
sref = (struct btrfs_shared_data_ref *)(iref + 1);
|
|
|
|
btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
|
|
|
|
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
|
|
|
|
} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
|
|
|
|
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
|
|
|
|
} else {
|
|
|
|
btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
|
|
|
|
}
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int lookup_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_extent_inline_ref **ref_ret,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
|
|
|
u64 root_objectid, u64 owner, u64 offset)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
|
|
|
|
bytenr, num_bytes, parent,
|
|
|
|
root_objectid, owner, offset, 0);
|
|
|
|
if (ret != -ENOENT)
|
2007-06-22 18:16:25 +00:00
|
|
|
return ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
*ref_ret = NULL;
|
|
|
|
|
|
|
|
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
|
|
|
|
root_objectid);
|
|
|
|
} else {
|
|
|
|
ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
|
|
|
|
root_objectid, owner, offset);
|
2009-03-13 15:00:37 +00:00
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
return ret;
|
|
|
|
}
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
/*
|
|
|
|
* helper to update/remove inline back ref
|
|
|
|
*/
|
|
|
|
static noinline_for_stack
|
|
|
|
int update_inline_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_extent_inline_ref *iref,
|
|
|
|
int refs_to_mod,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op)
|
|
|
|
{
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_extent_item *ei;
|
|
|
|
struct btrfs_extent_data_ref *dref = NULL;
|
|
|
|
struct btrfs_shared_data_ref *sref = NULL;
|
|
|
|
unsigned long ptr;
|
|
|
|
unsigned long end;
|
|
|
|
u32 item_size;
|
|
|
|
int size;
|
|
|
|
int type;
|
|
|
|
int ret;
|
|
|
|
u64 refs;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
refs = btrfs_extent_refs(leaf, ei);
|
|
|
|
WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
|
|
|
|
refs += refs_to_mod;
|
|
|
|
btrfs_set_extent_refs(leaf, ei, refs);
|
|
|
|
if (extent_op)
|
|
|
|
__run_delayed_extent_op(extent_op, leaf, ei);
|
|
|
|
|
|
|
|
type = btrfs_extent_inline_ref_type(leaf, iref);
|
|
|
|
|
|
|
|
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
|
|
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
|
|
refs = btrfs_extent_data_ref_count(leaf, dref);
|
|
|
|
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
|
|
|
|
sref = (struct btrfs_shared_data_ref *)(iref + 1);
|
|
|
|
refs = btrfs_shared_data_ref_count(leaf, sref);
|
|
|
|
} else {
|
|
|
|
refs = 1;
|
|
|
|
BUG_ON(refs_to_mod != -1);
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
|
|
|
|
refs += refs_to_mod;
|
|
|
|
|
|
|
|
if (refs > 0) {
|
|
|
|
if (type == BTRFS_EXTENT_DATA_REF_KEY)
|
|
|
|
btrfs_set_extent_data_ref_count(leaf, dref, refs);
|
|
|
|
else
|
|
|
|
btrfs_set_shared_data_ref_count(leaf, sref, refs);
|
|
|
|
} else {
|
|
|
|
size = btrfs_extent_inline_ref_size(type);
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
ptr = (unsigned long)iref;
|
|
|
|
end = (unsigned long)ei + item_size;
|
|
|
|
if (ptr + size < end)
|
|
|
|
memmove_extent_buffer(leaf, ptr, ptr + size,
|
|
|
|
end - ptr - size);
|
|
|
|
item_size -= size;
|
|
|
|
ret = btrfs_truncate_item(trans, root, path, item_size, 1);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static noinline_for_stack
|
|
|
|
int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
|
|
|
u64 root_objectid, u64 owner,
|
|
|
|
u64 offset, int refs_to_add,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op)
|
|
|
|
{
|
|
|
|
struct btrfs_extent_inline_ref *iref;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = lookup_inline_extent_backref(trans, root, path, &iref,
|
|
|
|
bytenr, num_bytes, parent,
|
|
|
|
root_objectid, owner, offset, 1);
|
|
|
|
if (ret == 0) {
|
|
|
|
BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
|
|
|
|
ret = update_inline_extent_backref(trans, root, path, iref,
|
|
|
|
refs_to_add, extent_op);
|
|
|
|
} else if (ret == -ENOENT) {
|
|
|
|
ret = setup_inline_extent_backref(trans, root, path, iref,
|
|
|
|
parent, root_objectid,
|
|
|
|
owner, offset, refs_to_add,
|
|
|
|
extent_op);
|
2008-11-07 03:02:51 +00:00
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
return ret;
|
|
|
|
}
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int insert_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 bytenr, u64 parent, u64 root_objectid,
|
|
|
|
u64 owner, u64 offset, int refs_to_add)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
BUG_ON(refs_to_add != 1);
|
|
|
|
ret = insert_tree_block_ref(trans, root, path, bytenr,
|
|
|
|
parent, root_objectid);
|
|
|
|
} else {
|
|
|
|
ret = insert_extent_data_ref(trans, root, path, bytenr,
|
|
|
|
parent, root_objectid,
|
|
|
|
owner, offset, refs_to_add);
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int remove_extent_backref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_extent_inline_ref *iref,
|
|
|
|
int refs_to_drop, int is_data)
|
|
|
|
{
|
|
|
|
int ret;
|
2009-03-13 15:00:37 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BUG_ON(!is_data && refs_to_drop != 1);
|
|
|
|
if (iref) {
|
|
|
|
ret = update_inline_extent_backref(trans, root, path, iref,
|
|
|
|
-refs_to_drop, NULL);
|
|
|
|
} else if (is_data) {
|
|
|
|
ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
|
|
|
|
} else {
|
|
|
|
ret = btrfs_del_item(trans, root, path);
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void btrfs_issue_discard(struct block_device *bdev,
|
|
|
|
u64 start, u64 len)
|
|
|
|
{
|
2009-09-12 05:35:43 +00:00
|
|
|
blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
|
2010-04-28 13:55:06 +00:00
|
|
|
BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
|
|
|
|
u64 num_bytes)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
u64 map_length = num_bytes;
|
|
|
|
struct btrfs_multi_bio *multi = NULL;
|
|
|
|
|
2009-10-14 13:24:59 +00:00
|
|
|
if (!btrfs_test_opt(root, DISCARD))
|
|
|
|
return 0;
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
/* Tell the block device(s) that the sectors can be discarded */
|
|
|
|
ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
|
|
|
|
bytenr, &map_length, &multi, 0);
|
|
|
|
if (!ret) {
|
|
|
|
struct btrfs_bio_stripe *stripe = multi->stripes;
|
|
|
|
int i;
|
|
|
|
|
|
|
|
if (map_length > num_bytes)
|
|
|
|
map_length = num_bytes;
|
|
|
|
|
|
|
|
for (i = 0; i < multi->num_stripes; i++, stripe++) {
|
|
|
|
btrfs_issue_discard(stripe->dev->bdev,
|
|
|
|
stripe->physical,
|
|
|
|
map_length);
|
|
|
|
}
|
|
|
|
kfree(multi);
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
|
|
|
u64 root_objectid, u64 owner, u64 offset)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
|
|
|
|
root_objectid == BTRFS_TREE_LOG_OBJECTID);
|
|
|
|
|
|
|
|
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
|
|
|
|
parent, root_objectid, (int)owner,
|
|
|
|
BTRFS_ADD_DELAYED_REF, NULL);
|
|
|
|
} else {
|
|
|
|
ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
|
|
|
|
parent, root_objectid, owner, offset,
|
|
|
|
BTRFS_ADD_DELAYED_REF, NULL);
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
u64 owner, u64 offset, int refs_to_add,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op)
|
|
|
|
{
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_extent_item *item;
|
|
|
|
u64 refs;
|
|
|
|
int ret;
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
path->reada = 1;
|
|
|
|
path->leave_spinning = 1;
|
|
|
|
/* this will setup the path even if it fails to insert the back ref */
|
|
|
|
ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
|
|
|
|
path, bytenr, num_bytes, parent,
|
|
|
|
root_objectid, owner, offset,
|
|
|
|
refs_to_add, extent_op);
|
|
|
|
if (ret == 0)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (ret != -EAGAIN) {
|
|
|
|
err = ret;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
refs = btrfs_extent_refs(leaf, item);
|
|
|
|
btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
|
|
|
|
if (extent_op)
|
|
|
|
__run_delayed_extent_op(extent_op, leaf, item);
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
2009-03-13 14:10:06 +00:00
|
|
|
btrfs_release_path(root->fs_info->extent_root, path);
|
|
|
|
|
|
|
|
path->reada = 1;
|
2009-03-13 15:00:37 +00:00
|
|
|
path->leave_spinning = 1;
|
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
/* now insert the actual backref */
|
|
|
|
ret = insert_extent_backref(trans, root->fs_info->extent_root,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
path, bytenr, parent, root_objectid,
|
|
|
|
owner, offset, refs_to_add);
|
2009-03-13 14:10:06 +00:00
|
|
|
BUG_ON(ret);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
out:
|
2009-03-13 14:10:06 +00:00
|
|
|
btrfs_free_path(path);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
return err;
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_delayed_ref_node *node,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op,
|
|
|
|
int insert_reserved)
|
2009-03-13 14:10:06 +00:00
|
|
|
{
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int ret = 0;
|
|
|
|
struct btrfs_delayed_data_ref *ref;
|
|
|
|
struct btrfs_key ins;
|
|
|
|
u64 parent = 0;
|
|
|
|
u64 ref_root = 0;
|
|
|
|
u64 flags = 0;
|
|
|
|
|
|
|
|
ins.objectid = node->bytenr;
|
|
|
|
ins.offset = node->num_bytes;
|
|
|
|
ins.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
|
|
|
|
ref = btrfs_delayed_node_to_data_ref(node);
|
|
|
|
if (node->type == BTRFS_SHARED_DATA_REF_KEY)
|
|
|
|
parent = ref->parent;
|
|
|
|
else
|
|
|
|
ref_root = ref->root;
|
|
|
|
|
|
|
|
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
|
|
|
|
if (extent_op) {
|
|
|
|
BUG_ON(extent_op->update_key);
|
|
|
|
flags |= extent_op->flags_to_set;
|
|
|
|
}
|
|
|
|
ret = alloc_reserved_file_extent(trans, root,
|
|
|
|
parent, ref_root, flags,
|
|
|
|
ref->objectid, ref->offset,
|
|
|
|
&ins, node->ref_mod);
|
|
|
|
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
|
|
|
|
ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
|
|
|
|
node->num_bytes, parent,
|
|
|
|
ref_root, ref->objectid,
|
|
|
|
ref->offset, node->ref_mod,
|
|
|
|
extent_op);
|
|
|
|
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
|
|
|
|
ret = __btrfs_free_extent(trans, root, node->bytenr,
|
|
|
|
node->num_bytes, parent,
|
|
|
|
ref_root, ref->objectid,
|
|
|
|
ref->offset, node->ref_mod,
|
|
|
|
extent_op);
|
|
|
|
} else {
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
|
|
|
|
struct extent_buffer *leaf,
|
|
|
|
struct btrfs_extent_item *ei)
|
|
|
|
{
|
|
|
|
u64 flags = btrfs_extent_flags(leaf, ei);
|
|
|
|
if (extent_op->update_flags) {
|
|
|
|
flags |= extent_op->flags_to_set;
|
|
|
|
btrfs_set_extent_flags(leaf, ei, flags);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (extent_op->update_key) {
|
|
|
|
struct btrfs_tree_block_info *bi;
|
|
|
|
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
|
|
|
|
bi = (struct btrfs_tree_block_info *)(ei + 1);
|
|
|
|
btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_delayed_ref_node *node,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op)
|
|
|
|
{
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct btrfs_extent_item *ei;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
u32 item_size;
|
2009-03-13 14:10:06 +00:00
|
|
|
int ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
key.objectid = node->bytenr;
|
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
key.offset = node->num_bytes;
|
|
|
|
|
|
|
|
path->reada = 1;
|
|
|
|
path->leave_spinning = 1;
|
|
|
|
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
|
|
|
|
path, 0, 1);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
if (ret > 0) {
|
|
|
|
err = -EIO;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
if (item_size < sizeof(*ei)) {
|
|
|
|
ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
|
|
|
|
path, (u64)-1, 0);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
BUG_ON(item_size < sizeof(*ei));
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
|
|
|
__run_delayed_extent_op(extent_op, leaf, ei);
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
out:
|
|
|
|
btrfs_free_path(path);
|
|
|
|
return err;
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_delayed_ref_node *node,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op,
|
|
|
|
int insert_reserved)
|
2009-03-13 14:10:06 +00:00
|
|
|
{
|
|
|
|
int ret = 0;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_delayed_tree_ref *ref;
|
|
|
|
struct btrfs_key ins;
|
|
|
|
u64 parent = 0;
|
|
|
|
u64 ref_root = 0;
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ins.objectid = node->bytenr;
|
|
|
|
ins.offset = node->num_bytes;
|
|
|
|
ins.type = BTRFS_EXTENT_ITEM_KEY;
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ref = btrfs_delayed_node_to_tree_ref(node);
|
|
|
|
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
|
|
|
|
parent = ref->parent;
|
|
|
|
else
|
|
|
|
ref_root = ref->root;
|
|
|
|
|
|
|
|
BUG_ON(node->ref_mod != 1);
|
|
|
|
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
|
|
|
|
BUG_ON(!extent_op || !extent_op->update_flags ||
|
|
|
|
!extent_op->update_key);
|
|
|
|
ret = alloc_reserved_tree_block(trans, root,
|
|
|
|
parent, ref_root,
|
|
|
|
extent_op->flags_to_set,
|
|
|
|
&extent_op->key,
|
|
|
|
ref->level, &ins);
|
|
|
|
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
|
|
|
|
ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
|
|
|
|
node->num_bytes, parent, ref_root,
|
|
|
|
ref->level, 0, 1, extent_op);
|
|
|
|
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
|
|
|
|
ret = __btrfs_free_extent(trans, root, node->bytenr,
|
|
|
|
node->num_bytes, parent, ref_root,
|
|
|
|
ref->level, 0, 1, extent_op);
|
|
|
|
} else {
|
|
|
|
BUG();
|
|
|
|
}
|
2009-03-13 14:10:06 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* helper function to actually process a single delayed ref entry */
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_delayed_ref_node *node,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op,
|
|
|
|
int insert_reserved)
|
2009-03-13 14:10:06 +00:00
|
|
|
{
|
|
|
|
int ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (btrfs_delayed_ref_is_head(node)) {
|
2009-03-13 14:10:06 +00:00
|
|
|
struct btrfs_delayed_ref_head *head;
|
|
|
|
/*
|
|
|
|
* we've hit the end of the chain and we were supposed
|
|
|
|
* to insert this extent into the tree. But, it got
|
|
|
|
* deleted before we ever needed to insert it, so all
|
|
|
|
* we have to do is clean up the accounting
|
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BUG_ON(extent_op);
|
|
|
|
head = btrfs_delayed_node_to_head(node);
|
2009-03-13 14:10:06 +00:00
|
|
|
if (insert_reserved) {
|
2010-05-16 14:46:25 +00:00
|
|
|
btrfs_pin_extent(root, node->bytenr,
|
|
|
|
node->num_bytes, 1);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (head->is_data) {
|
|
|
|
ret = btrfs_del_csums(trans, root,
|
|
|
|
node->bytenr,
|
|
|
|
node->num_bytes);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
|
|
|
mutex_unlock(&head->mutex);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
|
|
|
|
node->type == BTRFS_SHARED_BLOCK_REF_KEY)
|
|
|
|
ret = run_delayed_tree_ref(trans, root, node, extent_op,
|
|
|
|
insert_reserved);
|
|
|
|
else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
|
|
|
|
node->type == BTRFS_SHARED_DATA_REF_KEY)
|
|
|
|
ret = run_delayed_data_ref(trans, root, node, extent_op,
|
|
|
|
insert_reserved);
|
|
|
|
else
|
|
|
|
BUG();
|
|
|
|
return ret;
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static noinline struct btrfs_delayed_ref_node *
|
|
|
|
select_delayed_ref(struct btrfs_delayed_ref_head *head)
|
|
|
|
{
|
|
|
|
struct rb_node *node;
|
|
|
|
struct btrfs_delayed_ref_node *ref;
|
|
|
|
int action = BTRFS_ADD_DELAYED_REF;
|
|
|
|
again:
|
|
|
|
/*
|
|
|
|
* select delayed ref of type BTRFS_ADD_DELAYED_REF first.
|
|
|
|
* this prevents ref count from going down to zero when
|
|
|
|
* there still are pending delayed ref.
|
|
|
|
*/
|
|
|
|
node = rb_prev(&head->node.rb_node);
|
|
|
|
while (1) {
|
|
|
|
if (!node)
|
|
|
|
break;
|
|
|
|
ref = rb_entry(node, struct btrfs_delayed_ref_node,
|
|
|
|
rb_node);
|
|
|
|
if (ref->bytenr != head->node.bytenr)
|
|
|
|
break;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (ref->action == action)
|
2009-03-13 14:10:06 +00:00
|
|
|
return ref;
|
|
|
|
node = rb_prev(node);
|
|
|
|
}
|
|
|
|
if (action == BTRFS_ADD_DELAYED_REF) {
|
|
|
|
action = BTRFS_DROP_DELAYED_REF;
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
2009-03-13 14:17:05 +00:00
|
|
|
static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct list_head *cluster)
|
2009-03-13 14:10:06 +00:00
|
|
|
{
|
|
|
|
struct btrfs_delayed_ref_root *delayed_refs;
|
|
|
|
struct btrfs_delayed_ref_node *ref;
|
|
|
|
struct btrfs_delayed_ref_head *locked_ref = NULL;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_delayed_extent_op *extent_op;
|
2009-03-13 14:10:06 +00:00
|
|
|
int ret;
|
2009-03-13 14:17:05 +00:00
|
|
|
int count = 0;
|
2009-03-13 14:10:06 +00:00
|
|
|
int must_insert_reserved = 0;
|
|
|
|
|
|
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
|
|
while (1) {
|
|
|
|
if (!locked_ref) {
|
2009-03-13 14:17:05 +00:00
|
|
|
/* pick a new head ref from the cluster list */
|
|
|
|
if (list_empty(cluster))
|
2009-03-13 14:10:06 +00:00
|
|
|
break;
|
|
|
|
|
2009-03-13 14:17:05 +00:00
|
|
|
locked_ref = list_entry(cluster->next,
|
|
|
|
struct btrfs_delayed_ref_head, cluster);
|
|
|
|
|
|
|
|
/* grab the lock that says we are going to process
|
|
|
|
* all the refs for this head */
|
|
|
|
ret = btrfs_delayed_ref_lock(trans, locked_ref);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* we may have dropped the spin lock to get the head
|
|
|
|
* mutex lock, and that might have given someone else
|
|
|
|
* time to free the head. If that's true, it has been
|
|
|
|
* removed from our list and we can move on.
|
|
|
|
*/
|
|
|
|
if (ret == -EAGAIN) {
|
|
|
|
locked_ref = NULL;
|
|
|
|
count++;
|
|
|
|
continue;
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
|
|
|
}
|
2007-03-07 01:08:01 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
/*
|
|
|
|
* record the must insert reserved flag before we
|
|
|
|
* drop the spin lock.
|
|
|
|
*/
|
|
|
|
must_insert_reserved = locked_ref->must_insert_reserved;
|
|
|
|
locked_ref->must_insert_reserved = 0;
|
2007-12-11 14:25:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
extent_op = locked_ref->extent_op;
|
|
|
|
locked_ref->extent_op = NULL;
|
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
/*
|
|
|
|
* locked_ref is the head node, so we have to go one
|
|
|
|
* node back for any delayed ref updates
|
|
|
|
*/
|
|
|
|
ref = select_delayed_ref(locked_ref);
|
|
|
|
if (!ref) {
|
|
|
|
/* All delayed refs have been processed, Go ahead
|
|
|
|
* and send the head node to run_one_delayed_ref,
|
|
|
|
* so that any accounting fixes can happen
|
|
|
|
*/
|
|
|
|
ref = &locked_ref->node;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
if (extent_op && must_insert_reserved) {
|
|
|
|
kfree(extent_op);
|
|
|
|
extent_op = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (extent_op) {
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
|
|
|
|
ret = run_delayed_extent_op(trans, root,
|
|
|
|
ref, extent_op);
|
|
|
|
BUG_ON(ret);
|
|
|
|
kfree(extent_op);
|
|
|
|
|
|
|
|
cond_resched();
|
|
|
|
spin_lock(&delayed_refs->lock);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
2009-03-13 14:17:05 +00:00
|
|
|
list_del_init(&locked_ref->cluster);
|
2009-03-13 14:10:06 +00:00
|
|
|
locked_ref = NULL;
|
|
|
|
}
|
2007-03-02 21:08:05 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
ref->in_tree = 0;
|
|
|
|
rb_erase(&ref->rb_node, &delayed_refs->root);
|
|
|
|
delayed_refs->num_entries--;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
spin_unlock(&delayed_refs->lock);
|
2008-06-25 20:01:30 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret = run_one_delayed_ref(trans, root, ref, extent_op,
|
2009-03-13 14:10:06 +00:00
|
|
|
must_insert_reserved);
|
|
|
|
BUG_ON(ret);
|
2009-02-12 14:27:38 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_put_delayed_ref(ref);
|
|
|
|
kfree(extent_op);
|
2009-03-13 14:17:05 +00:00
|
|
|
count++;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2009-03-13 14:17:05 +00:00
|
|
|
cond_resched();
|
|
|
|
spin_lock(&delayed_refs->lock);
|
|
|
|
}
|
|
|
|
return count;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* this starts processing the delayed reference count updates and
|
|
|
|
* extent insertions we have queued up so far. count can be
|
|
|
|
* 0, which means to process everything in the tree at the start
|
|
|
|
* of the run (but not newly added entries), or it can be some target
|
|
|
|
* number you'd like to process.
|
|
|
|
*/
|
|
|
|
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, unsigned long count)
|
|
|
|
{
|
|
|
|
struct rb_node *node;
|
|
|
|
struct btrfs_delayed_ref_root *delayed_refs;
|
|
|
|
struct btrfs_delayed_ref_node *ref;
|
|
|
|
struct list_head cluster;
|
|
|
|
int ret;
|
|
|
|
int run_all = count == (unsigned long)-1;
|
|
|
|
int run_most = 0;
|
|
|
|
|
|
|
|
if (root == root->fs_info->extent_root)
|
|
|
|
root = root->fs_info->tree_root;
|
|
|
|
|
|
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
|
|
INIT_LIST_HEAD(&cluster);
|
|
|
|
again:
|
|
|
|
spin_lock(&delayed_refs->lock);
|
|
|
|
if (count == 0) {
|
|
|
|
count = delayed_refs->num_entries * 2;
|
|
|
|
run_most = 1;
|
|
|
|
}
|
|
|
|
while (1) {
|
|
|
|
if (!(run_all || run_most) &&
|
|
|
|
delayed_refs->num_heads_ready < 64)
|
|
|
|
break;
|
2009-02-12 14:27:38 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
/*
|
2009-03-13 14:17:05 +00:00
|
|
|
* go find something we can process in the rbtree. We start at
|
|
|
|
* the beginning of the tree, and then build a cluster
|
|
|
|
* of refs to process starting at the first one we are able to
|
|
|
|
* lock
|
2009-03-13 14:10:06 +00:00
|
|
|
*/
|
2009-03-13 14:17:05 +00:00
|
|
|
ret = btrfs_find_ref_cluster(trans, &cluster,
|
|
|
|
delayed_refs->run_delayed_start);
|
|
|
|
if (ret)
|
2009-03-13 14:10:06 +00:00
|
|
|
break;
|
|
|
|
|
2009-03-13 14:17:05 +00:00
|
|
|
ret = run_clustered_refs(trans, root, &cluster);
|
|
|
|
BUG_ON(ret < 0);
|
|
|
|
|
|
|
|
count -= min_t(unsigned long, ret, count);
|
|
|
|
|
|
|
|
if (count == 0)
|
|
|
|
break;
|
2009-02-12 14:27:38 +00:00
|
|
|
}
|
2009-03-13 14:17:05 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
if (run_all) {
|
|
|
|
node = rb_first(&delayed_refs->root);
|
2009-03-13 14:17:05 +00:00
|
|
|
if (!node)
|
2009-03-13 14:10:06 +00:00
|
|
|
goto out;
|
2009-03-13 14:17:05 +00:00
|
|
|
count = (unsigned long)-1;
|
2007-08-10 18:06:19 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
while (node) {
|
|
|
|
ref = rb_entry(node, struct btrfs_delayed_ref_node,
|
|
|
|
rb_node);
|
|
|
|
if (btrfs_delayed_ref_is_head(ref)) {
|
|
|
|
struct btrfs_delayed_ref_head *head;
|
2007-04-02 15:20:42 +00:00
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
head = btrfs_delayed_node_to_head(ref);
|
|
|
|
atomic_inc(&ref->refs);
|
|
|
|
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
mutex_lock(&head->mutex);
|
|
|
|
mutex_unlock(&head->mutex);
|
|
|
|
|
|
|
|
btrfs_put_delayed_ref(ref);
|
2009-03-13 14:11:24 +00:00
|
|
|
cond_resched();
|
2009-03-13 14:10:06 +00:00
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
node = rb_next(node);
|
|
|
|
}
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
schedule_timeout(1);
|
|
|
|
goto again;
|
2007-10-15 20:14:19 +00:00
|
|
|
}
|
2007-06-22 18:16:25 +00:00
|
|
|
out:
|
2009-03-13 14:17:05 +00:00
|
|
|
spin_unlock(&delayed_refs->lock);
|
2007-03-07 01:08:01 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 flags,
|
|
|
|
int is_data)
|
|
|
|
{
|
|
|
|
struct btrfs_delayed_extent_op *extent_op;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
|
|
|
|
if (!extent_op)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
extent_op->flags_to_set = flags;
|
|
|
|
extent_op->update_flags = 1;
|
|
|
|
extent_op->update_key = 0;
|
|
|
|
extent_op->is_data = is_data ? 1 : 0;
|
|
|
|
|
|
|
|
ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
|
|
|
|
if (ret)
|
|
|
|
kfree(extent_op);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 objectid, u64 offset, u64 bytenr)
|
|
|
|
{
|
|
|
|
struct btrfs_delayed_ref_head *head;
|
|
|
|
struct btrfs_delayed_ref_node *ref;
|
|
|
|
struct btrfs_delayed_data_ref *data_ref;
|
|
|
|
struct btrfs_delayed_ref_root *delayed_refs;
|
|
|
|
struct rb_node *node;
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
ret = -ENOENT;
|
|
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
|
|
spin_lock(&delayed_refs->lock);
|
|
|
|
head = btrfs_find_delayed_ref_head(trans, bytenr);
|
|
|
|
if (!head)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (!mutex_trylock(&head->mutex)) {
|
|
|
|
atomic_inc(&head->node.refs);
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
|
|
|
|
btrfs_release_path(root->fs_info->extent_root, path);
|
|
|
|
|
|
|
|
mutex_lock(&head->mutex);
|
|
|
|
mutex_unlock(&head->mutex);
|
|
|
|
btrfs_put_delayed_ref(&head->node);
|
|
|
|
return -EAGAIN;
|
|
|
|
}
|
|
|
|
|
|
|
|
node = rb_prev(&head->node.rb_node);
|
|
|
|
if (!node)
|
|
|
|
goto out_unlock;
|
|
|
|
|
|
|
|
ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
|
|
|
|
|
|
|
|
if (ref->bytenr != bytenr)
|
|
|
|
goto out_unlock;
|
|
|
|
|
|
|
|
ret = 1;
|
|
|
|
if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
|
|
|
|
goto out_unlock;
|
|
|
|
|
|
|
|
data_ref = btrfs_delayed_node_to_data_ref(ref);
|
|
|
|
|
|
|
|
node = rb_prev(node);
|
|
|
|
if (node) {
|
|
|
|
ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
|
|
|
|
if (ref->bytenr == bytenr)
|
|
|
|
goto out_unlock;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (data_ref->root != root->root_key.objectid ||
|
|
|
|
data_ref->objectid != objectid || data_ref->offset != offset)
|
|
|
|
goto out_unlock;
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
out_unlock:
|
|
|
|
mutex_unlock(&head->mutex);
|
|
|
|
out:
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 objectid, u64 offset, u64 bytenr)
|
2007-12-18 01:14:01 +00:00
|
|
|
{
|
|
|
|
struct btrfs_root *extent_root = root->fs_info->extent_root;
|
2008-07-30 13:26:11 +00:00
|
|
|
struct extent_buffer *leaf;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_extent_data_ref *ref;
|
|
|
|
struct btrfs_extent_inline_ref *iref;
|
|
|
|
struct btrfs_extent_item *ei;
|
2008-07-30 13:26:11 +00:00
|
|
|
struct btrfs_key key;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u32 item_size;
|
2007-12-18 01:14:01 +00:00
|
|
|
int ret;
|
2008-06-25 20:01:30 +00:00
|
|
|
|
2007-12-18 01:14:01 +00:00
|
|
|
key.objectid = bytenr;
|
2008-09-23 17:14:14 +00:00
|
|
|
key.offset = (u64)-1;
|
2008-07-30 13:26:11 +00:00
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
2007-12-18 01:14:01 +00:00
|
|
|
|
|
|
|
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
BUG_ON(ret == 0);
|
2008-10-30 18:20:02 +00:00
|
|
|
|
|
|
|
ret = -ENOENT;
|
|
|
|
if (path->slots[0] == 0)
|
2008-09-23 17:14:14 +00:00
|
|
|
goto out;
|
2007-12-18 01:14:01 +00:00
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
path->slots[0]--;
|
2008-07-30 13:26:11 +00:00
|
|
|
leaf = path->nodes[0];
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
2007-12-18 01:14:01 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
|
2007-12-18 01:14:01 +00:00
|
|
|
goto out;
|
2008-07-30 13:26:11 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret = 1;
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
if (item_size < sizeof(*ei)) {
|
|
|
|
WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
|
2008-01-03 18:23:19 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (item_size != sizeof(*ei) +
|
|
|
|
btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
|
|
|
|
goto out;
|
2007-12-18 01:14:01 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (btrfs_extent_generation(leaf, ei) <=
|
|
|
|
btrfs_root_last_snapshot(&root->root_item))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)(ei + 1);
|
|
|
|
if (btrfs_extent_inline_ref_type(leaf, iref) !=
|
|
|
|
BTRFS_EXTENT_DATA_REF_KEY)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
|
|
if (btrfs_extent_refs(leaf, ei) !=
|
|
|
|
btrfs_extent_data_ref_count(leaf, ref) ||
|
|
|
|
btrfs_extent_data_ref_root(leaf, ref) !=
|
|
|
|
root->root_key.objectid ||
|
|
|
|
btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
|
|
|
|
btrfs_extent_data_ref_offset(leaf, ref) != offset)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 objectid, u64 offset, u64 bytenr)
|
|
|
|
{
|
|
|
|
struct btrfs_path *path;
|
|
|
|
int ret;
|
|
|
|
int ret2;
|
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOENT;
|
|
|
|
|
|
|
|
do {
|
|
|
|
ret = check_committed_ref(trans, root, path, objectid,
|
|
|
|
offset, bytenr);
|
|
|
|
if (ret && ret != -ENOENT)
|
2008-07-30 13:26:11 +00:00
|
|
|
goto out;
|
2008-10-30 18:20:02 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret2 = check_delayed_ref(trans, root, path, objectid,
|
|
|
|
offset, bytenr);
|
|
|
|
} while (ret2 == -EAGAIN);
|
|
|
|
|
|
|
|
if (ret2 && ret2 != -ENOENT) {
|
|
|
|
ret = ret2;
|
|
|
|
goto out;
|
2008-07-30 13:26:11 +00:00
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
if (ret != -ENOENT || ret2 != -ENOENT)
|
|
|
|
ret = 0;
|
2007-12-18 01:14:01 +00:00
|
|
|
out:
|
2008-10-30 18:20:02 +00:00
|
|
|
btrfs_free_path(path);
|
2010-05-16 14:46:25 +00:00
|
|
|
if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
|
|
|
|
WARN_ON(ret > 0);
|
2008-07-30 13:26:11 +00:00
|
|
|
return ret;
|
2007-12-18 01:14:01 +00:00
|
|
|
}
|
2007-04-10 13:27:04 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#if 0
|
2008-09-23 17:14:14 +00:00
|
|
|
int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf, u32 nr_extents)
|
2007-03-02 21:08:05 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_key key;
|
2007-03-27 10:33:00 +00:00
|
|
|
struct btrfs_file_extent_item *fi;
|
2008-09-26 14:04:53 +00:00
|
|
|
u64 root_gen;
|
|
|
|
u32 nritems;
|
2007-03-02 21:08:05 +00:00
|
|
|
int i;
|
2007-10-15 20:15:53 +00:00
|
|
|
int level;
|
2008-09-23 17:14:14 +00:00
|
|
|
int ret = 0;
|
2008-09-26 14:04:53 +00:00
|
|
|
int shared = 0;
|
2007-03-07 01:08:01 +00:00
|
|
|
|
2007-03-13 20:47:54 +00:00
|
|
|
if (!root->ref_cows)
|
2007-03-07 01:08:01 +00:00
|
|
|
return 0;
|
2007-10-15 20:14:19 +00:00
|
|
|
|
2008-09-26 14:04:53 +00:00
|
|
|
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
|
|
|
|
shared = 0;
|
|
|
|
root_gen = root->root_key.offset;
|
|
|
|
} else {
|
|
|
|
shared = 1;
|
|
|
|
root_gen = trans->transid - 1;
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
level = btrfs_header_level(buf);
|
2007-10-15 20:14:19 +00:00
|
|
|
nritems = btrfs_header_nritems(buf);
|
2008-07-21 14:29:44 +00:00
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
if (level == 0) {
|
2008-07-28 19:32:19 +00:00
|
|
|
struct btrfs_leaf_ref *ref;
|
|
|
|
struct btrfs_extent_info *info;
|
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
ref = btrfs_alloc_leaf_ref(root, nr_extents);
|
2008-07-28 19:32:19 +00:00
|
|
|
if (!ref) {
|
2008-09-23 17:14:14 +00:00
|
|
|
ret = -ENOMEM;
|
2008-07-28 19:32:19 +00:00
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
2008-09-26 14:04:53 +00:00
|
|
|
ref->root_gen = root_gen;
|
2008-07-28 19:32:19 +00:00
|
|
|
ref->bytenr = buf->start;
|
|
|
|
ref->owner = btrfs_header_owner(buf);
|
|
|
|
ref->generation = btrfs_header_generation(buf);
|
2008-09-23 17:14:14 +00:00
|
|
|
ref->nritems = nr_extents;
|
2008-07-28 19:32:19 +00:00
|
|
|
info = ref->extents;
|
2008-07-30 20:29:20 +00:00
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
for (i = 0; nr_extents > 0 && i < nritems; i++) {
|
2008-07-28 19:32:19 +00:00
|
|
|
u64 disk_bytenr;
|
|
|
|
btrfs_item_key_to_cpu(buf, &key, i);
|
|
|
|
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
|
|
|
|
continue;
|
|
|
|
fi = btrfs_item_ptr(buf, i,
|
|
|
|
struct btrfs_file_extent_item);
|
|
|
|
if (btrfs_file_extent_type(buf, fi) ==
|
|
|
|
BTRFS_FILE_EXTENT_INLINE)
|
|
|
|
continue;
|
|
|
|
disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
|
|
|
|
if (disk_bytenr == 0)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
info->bytenr = disk_bytenr;
|
|
|
|
info->num_bytes =
|
|
|
|
btrfs_file_extent_disk_num_bytes(buf, fi);
|
|
|
|
info->objectid = key.objectid;
|
|
|
|
info->offset = key.offset;
|
|
|
|
info++;
|
|
|
|
}
|
|
|
|
|
2008-09-26 14:04:53 +00:00
|
|
|
ret = btrfs_add_leaf_ref(root, ref, shared);
|
2008-10-09 15:46:19 +00:00
|
|
|
if (ret == -EEXIST && shared) {
|
|
|
|
struct btrfs_leaf_ref *old;
|
|
|
|
old = btrfs_lookup_leaf_ref(root, ref->bytenr);
|
|
|
|
BUG_ON(!old);
|
|
|
|
btrfs_remove_leaf_ref(root, old);
|
|
|
|
btrfs_free_leaf_ref(root, old);
|
|
|
|
ret = btrfs_add_leaf_ref(root, ref, shared);
|
|
|
|
}
|
2008-07-28 19:32:19 +00:00
|
|
|
WARN_ON(ret);
|
2008-07-30 20:29:20 +00:00
|
|
|
btrfs_free_leaf_ref(root, ref);
|
2008-07-28 19:32:19 +00:00
|
|
|
}
|
|
|
|
out:
|
2008-09-23 17:14:14 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2009-02-04 14:23:45 +00:00
|
|
|
/* when a block goes through cow, we update the reference counts of
|
|
|
|
* everything that block points to. The internal pointers of the block
|
|
|
|
* can be in just about any order, and it is likely to have clusters of
|
|
|
|
* things that are close together and clusters of things that are not.
|
|
|
|
*
|
|
|
|
* To help reduce the seeks that come with updating all of these reference
|
|
|
|
* counts, sort them by byte number before actual updates are done.
|
|
|
|
*
|
|
|
|
* struct refsort is used to match byte number to slot in the btree block.
|
|
|
|
* we sort based on the byte number and then use the slot to actually
|
|
|
|
* find the item.
|
2009-02-04 14:27:02 +00:00
|
|
|
*
|
|
|
|
* struct refsort is smaller than strcut btrfs_item and smaller than
|
|
|
|
* struct btrfs_key_ptr. Since we're currently limited to the page size
|
|
|
|
* for a btree block, there's no way for a kmalloc of refsorts for a
|
|
|
|
* single node to be bigger than a page.
|
2009-02-04 14:23:45 +00:00
|
|
|
*/
|
|
|
|
struct refsort {
|
|
|
|
u64 bytenr;
|
|
|
|
u32 slot;
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* for passing into sort()
|
|
|
|
*/
|
|
|
|
static int refsort_cmp(const void *a_void, const void *b_void)
|
|
|
|
{
|
|
|
|
const struct refsort *a = a_void;
|
|
|
|
const struct refsort *b = b_void;
|
|
|
|
|
|
|
|
if (a->bytenr < b->bytenr)
|
|
|
|
return -1;
|
|
|
|
if (a->bytenr > b->bytenr)
|
|
|
|
return 1;
|
|
|
|
return 0;
|
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#endif
|
2009-02-04 14:23:45 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
|
2009-02-04 14:23:45 +00:00
|
|
|
struct btrfs_root *root,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct extent_buffer *buf,
|
|
|
|
int full_backref, int inc)
|
2008-09-23 17:14:14 +00:00
|
|
|
{
|
|
|
|
u64 bytenr;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u64 num_bytes;
|
|
|
|
u64 parent;
|
2008-09-23 17:14:14 +00:00
|
|
|
u64 ref_root;
|
|
|
|
u32 nritems;
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_file_extent_item *fi;
|
|
|
|
int i;
|
|
|
|
int level;
|
|
|
|
int ret = 0;
|
|
|
|
int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u64, u64, u64, u64, u64, u64);
|
2008-09-23 17:14:14 +00:00
|
|
|
|
|
|
|
ref_root = btrfs_header_owner(buf);
|
|
|
|
nritems = btrfs_header_nritems(buf);
|
|
|
|
level = btrfs_header_level(buf);
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (!root->ref_cows && level == 0)
|
|
|
|
return 0;
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (inc)
|
|
|
|
process_func = btrfs_inc_extent_ref;
|
|
|
|
else
|
|
|
|
process_func = btrfs_free_extent;
|
2008-09-23 17:14:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (full_backref)
|
|
|
|
parent = buf->start;
|
|
|
|
else
|
|
|
|
parent = 0;
|
|
|
|
|
|
|
|
for (i = 0; i < nritems; i++) {
|
2008-09-23 17:14:14 +00:00
|
|
|
if (level == 0) {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_item_key_to_cpu(buf, &key, i);
|
2008-09-23 17:14:14 +00:00
|
|
|
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
|
|
|
|
continue;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
fi = btrfs_item_ptr(buf, i,
|
2008-09-23 17:14:14 +00:00
|
|
|
struct btrfs_file_extent_item);
|
|
|
|
if (btrfs_file_extent_type(buf, fi) ==
|
|
|
|
BTRFS_FILE_EXTENT_INLINE)
|
|
|
|
continue;
|
|
|
|
bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
|
|
|
|
if (bytenr == 0)
|
|
|
|
continue;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
|
|
|
|
key.offset -= btrfs_file_extent_offset(buf, fi);
|
|
|
|
ret = process_func(trans, root, bytenr, num_bytes,
|
|
|
|
parent, ref_root, key.objectid,
|
|
|
|
key.offset);
|
2008-09-23 17:14:14 +00:00
|
|
|
if (ret)
|
|
|
|
goto fail;
|
|
|
|
} else {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
bytenr = btrfs_node_blockptr(buf, i);
|
|
|
|
num_bytes = btrfs_level_size(root, level - 1);
|
|
|
|
ret = process_func(trans, root, bytenr, num_bytes,
|
|
|
|
parent, ref_root, level - 1, 0);
|
2008-09-23 17:14:14 +00:00
|
|
|
if (ret)
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
fail:
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BUG();
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf, int full_backref)
|
|
|
|
{
|
|
|
|
return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf, int full_backref)
|
|
|
|
{
|
|
|
|
return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
|
2008-09-23 17:14:14 +00:00
|
|
|
}
|
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
static int write_one_cache_group(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
struct btrfs_root *extent_root = root->fs_info->extent_root;
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long bi;
|
|
|
|
struct extent_buffer *leaf;
|
2007-04-26 20:46:15 +00:00
|
|
|
|
|
|
|
ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
|
2007-06-22 18:16:25 +00:00
|
|
|
if (ret < 0)
|
|
|
|
goto fail;
|
2007-04-26 20:46:15 +00:00
|
|
|
BUG_ON(ret);
|
2007-10-15 20:14:19 +00:00
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
|
|
|
|
write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
2007-04-26 20:46:15 +00:00
|
|
|
btrfs_release_path(extent_root, path);
|
2007-06-22 18:16:25 +00:00
|
|
|
fail:
|
2007-04-26 20:46:15 +00:00
|
|
|
if (ret)
|
|
|
|
return ret;
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
2009-07-22 14:07:05 +00:00
|
|
|
static struct btrfs_block_group_cache *
|
|
|
|
next_block_group(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
struct rb_node *node;
|
|
|
|
spin_lock(&root->fs_info->block_group_cache_lock);
|
|
|
|
node = rb_next(&cache->cache_node);
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
if (node) {
|
|
|
|
cache = rb_entry(node, struct btrfs_block_group_cache,
|
|
|
|
cache_node);
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_get_block_group(cache);
|
2009-07-22 14:07:05 +00:00
|
|
|
} else
|
|
|
|
cache = NULL;
|
|
|
|
spin_unlock(&root->fs_info->block_group_cache_lock);
|
|
|
|
return cache;
|
|
|
|
}
|
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
static int cache_save_setup(struct btrfs_block_group_cache *block_group,
|
|
|
|
struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_path *path)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = block_group->fs_info->tree_root;
|
|
|
|
struct inode *inode = NULL;
|
|
|
|
u64 alloc_hint = 0;
|
2010-12-03 18:17:53 +00:00
|
|
|
int dcs = BTRFS_DC_ERROR;
|
2010-06-21 18:48:16 +00:00
|
|
|
int num_pages = 0;
|
|
|
|
int retries = 0;
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If this block group is smaller than 100 megs don't bother caching the
|
|
|
|
* block group.
|
|
|
|
*/
|
|
|
|
if (block_group->key.offset < (100 * 1024 * 1024)) {
|
|
|
|
spin_lock(&block_group->lock);
|
|
|
|
block_group->disk_cache_state = BTRFS_DC_WRITTEN;
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
again:
|
|
|
|
inode = lookup_free_space_inode(root, block_group, path);
|
|
|
|
if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
|
|
|
|
ret = PTR_ERR(inode);
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (IS_ERR(inode)) {
|
|
|
|
BUG_ON(retries);
|
|
|
|
retries++;
|
|
|
|
|
|
|
|
if (block_group->ro)
|
|
|
|
goto out_free;
|
|
|
|
|
|
|
|
ret = create_free_space_inode(root, trans, block_group, path);
|
|
|
|
if (ret)
|
|
|
|
goto out_free;
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We want to set the generation to 0, that way if anything goes wrong
|
|
|
|
* from here on out we know not to trust this cache when we load up next
|
|
|
|
* time.
|
|
|
|
*/
|
|
|
|
BTRFS_I(inode)->generation = 0;
|
|
|
|
ret = btrfs_update_inode(trans, root, inode);
|
|
|
|
WARN_ON(ret);
|
|
|
|
|
|
|
|
if (i_size_read(inode) > 0) {
|
|
|
|
ret = btrfs_truncate_free_space_cache(root, trans, path,
|
|
|
|
inode);
|
|
|
|
if (ret)
|
|
|
|
goto out_put;
|
|
|
|
}
|
|
|
|
|
|
|
|
spin_lock(&block_group->lock);
|
|
|
|
if (block_group->cached != BTRFS_CACHE_FINISHED) {
|
2010-12-03 18:17:53 +00:00
|
|
|
/* We're not cached, don't bother trying to write stuff out */
|
|
|
|
dcs = BTRFS_DC_WRITTEN;
|
2010-06-21 18:48:16 +00:00
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
goto out_put;
|
|
|
|
}
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
|
|
|
|
num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
|
|
|
|
if (!num_pages)
|
|
|
|
num_pages = 1;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Just to make absolutely sure we have enough space, we're going to
|
|
|
|
* preallocate 12 pages worth of space for each block group. In
|
|
|
|
* practice we ought to use at most 8, but we need extra space so we can
|
|
|
|
* add our header and have a terminator between the extents and the
|
|
|
|
* bitmaps.
|
|
|
|
*/
|
|
|
|
num_pages *= 16;
|
|
|
|
num_pages *= PAGE_CACHE_SIZE;
|
|
|
|
|
|
|
|
ret = btrfs_check_data_free_space(inode, num_pages);
|
|
|
|
if (ret)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
|
|
|
|
num_pages, num_pages,
|
|
|
|
&alloc_hint);
|
2010-12-03 18:17:53 +00:00
|
|
|
if (!ret)
|
|
|
|
dcs = BTRFS_DC_SETUP;
|
2010-06-21 18:48:16 +00:00
|
|
|
btrfs_free_reserved_data_space(inode, num_pages);
|
|
|
|
out_put:
|
|
|
|
iput(inode);
|
|
|
|
out_free:
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
out:
|
|
|
|
spin_lock(&block_group->lock);
|
2010-12-03 18:17:53 +00:00
|
|
|
block_group->disk_cache_state = dcs;
|
2010-06-21 18:48:16 +00:00
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:15:19 +00:00
|
|
|
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root)
|
2007-04-26 20:46:15 +00:00
|
|
|
{
|
2009-07-22 14:07:05 +00:00
|
|
|
struct btrfs_block_group_cache *cache;
|
2007-04-26 20:46:15 +00:00
|
|
|
int err = 0;
|
|
|
|
struct btrfs_path *path;
|
2007-10-15 20:15:19 +00:00
|
|
|
u64 last = 0;
|
2007-04-26 20:46:15 +00:00
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
again:
|
|
|
|
while (1) {
|
|
|
|
cache = btrfs_lookup_first_block_group(root->fs_info, last);
|
|
|
|
while (cache) {
|
|
|
|
if (cache->disk_cache_state == BTRFS_DC_CLEAR)
|
|
|
|
break;
|
|
|
|
cache = next_block_group(root, cache);
|
|
|
|
}
|
|
|
|
if (!cache) {
|
|
|
|
if (last == 0)
|
|
|
|
break;
|
|
|
|
last = 0;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
err = cache_save_setup(cache, trans, path);
|
|
|
|
last = cache->key.objectid + cache->key.offset;
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (1) {
|
2009-07-22 14:07:05 +00:00
|
|
|
if (last == 0) {
|
|
|
|
err = btrfs_run_delayed_refs(trans, root,
|
|
|
|
(unsigned long)-1);
|
|
|
|
BUG_ON(err);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
}
|
2007-06-22 18:16:25 +00:00
|
|
|
|
2009-07-22 14:07:05 +00:00
|
|
|
cache = btrfs_lookup_first_block_group(root->fs_info, last);
|
|
|
|
while (cache) {
|
2010-06-21 18:48:16 +00:00
|
|
|
if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
|
2009-07-22 14:07:05 +00:00
|
|
|
if (cache->dirty)
|
|
|
|
break;
|
|
|
|
cache = next_block_group(root, cache);
|
|
|
|
}
|
|
|
|
if (!cache) {
|
|
|
|
if (last == 0)
|
|
|
|
break;
|
|
|
|
last = 0;
|
|
|
|
continue;
|
|
|
|
}
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2010-07-02 16:14:14 +00:00
|
|
|
if (cache->disk_cache_state == BTRFS_DC_SETUP)
|
|
|
|
cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
|
2008-09-26 14:05:48 +00:00
|
|
|
cache->dirty = 0;
|
2009-07-22 14:07:05 +00:00
|
|
|
last = cache->key.objectid + cache->key.offset;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2009-07-22 14:07:05 +00:00
|
|
|
err = write_one_cache_group(trans, root, path, cache);
|
|
|
|
BUG_ON(err);
|
|
|
|
btrfs_put_block_group(cache);
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
2009-07-22 14:07:05 +00:00
|
|
|
|
2010-07-02 16:14:14 +00:00
|
|
|
while (1) {
|
|
|
|
/*
|
|
|
|
* I don't think this is needed since we're just marking our
|
|
|
|
* preallocated extent as written, but just in case it can't
|
|
|
|
* hurt.
|
|
|
|
*/
|
|
|
|
if (last == 0) {
|
|
|
|
err = btrfs_run_delayed_refs(trans, root,
|
|
|
|
(unsigned long)-1);
|
|
|
|
BUG_ON(err);
|
|
|
|
}
|
|
|
|
|
|
|
|
cache = btrfs_lookup_first_block_group(root->fs_info, last);
|
|
|
|
while (cache) {
|
|
|
|
/*
|
|
|
|
* Really this shouldn't happen, but it could if we
|
|
|
|
* couldn't write the entire preallocated extent and
|
|
|
|
* splitting the extent resulted in a new block.
|
|
|
|
*/
|
|
|
|
if (cache->dirty) {
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
|
|
|
|
break;
|
|
|
|
cache = next_block_group(root, cache);
|
|
|
|
}
|
|
|
|
if (!cache) {
|
|
|
|
if (last == 0)
|
|
|
|
break;
|
|
|
|
last = 0;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
btrfs_write_out_cache(root, trans, cache, path);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If we didn't have an error then the cache state is still
|
|
|
|
* NEED_WRITE, so we can set it to WRITTEN.
|
|
|
|
*/
|
|
|
|
if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
|
|
|
|
cache->disk_cache_state = BTRFS_DC_WRITTEN;
|
|
|
|
last = cache->key.objectid + cache->key.offset;
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
}
|
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
btrfs_free_path(path);
|
2009-07-22 14:07:05 +00:00
|
|
|
return 0;
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
|
|
|
|
2008-12-11 21:30:39 +00:00
|
|
|
int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
|
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
|
|
|
int readonly = 0;
|
|
|
|
|
|
|
|
block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
|
|
|
|
if (!block_group || block_group->ro)
|
|
|
|
readonly = 1;
|
|
|
|
if (block_group)
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
2008-12-11 21:30:39 +00:00
|
|
|
return readonly;
|
|
|
|
}
|
|
|
|
|
2008-03-25 20:50:33 +00:00
|
|
|
static int update_space_info(struct btrfs_fs_info *info, u64 flags,
|
|
|
|
u64 total_bytes, u64 bytes_used,
|
|
|
|
struct btrfs_space_info **space_info)
|
|
|
|
{
|
|
|
|
struct btrfs_space_info *found;
|
2010-05-16 14:46:24 +00:00
|
|
|
int i;
|
|
|
|
int factor;
|
|
|
|
|
|
|
|
if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID10))
|
|
|
|
factor = 2;
|
|
|
|
else
|
|
|
|
factor = 1;
|
2008-03-25 20:50:33 +00:00
|
|
|
|
|
|
|
found = __find_space_info(info, flags);
|
|
|
|
if (found) {
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_lock(&found->lock);
|
2008-03-25 20:50:33 +00:00
|
|
|
found->total_bytes += total_bytes;
|
2010-10-14 18:52:27 +00:00
|
|
|
found->disk_total += total_bytes * factor;
|
2008-03-25 20:50:33 +00:00
|
|
|
found->bytes_used += bytes_used;
|
2010-05-16 14:46:24 +00:00
|
|
|
found->disk_used += bytes_used * factor;
|
2008-04-25 20:53:30 +00:00
|
|
|
found->full = 0;
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_unlock(&found->lock);
|
2008-03-25 20:50:33 +00:00
|
|
|
*space_info = found;
|
|
|
|
return 0;
|
|
|
|
}
|
2008-11-12 19:34:12 +00:00
|
|
|
found = kzalloc(sizeof(*found), GFP_NOFS);
|
2008-03-25 20:50:33 +00:00
|
|
|
if (!found)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
|
|
|
|
INIT_LIST_HEAD(&found->block_groups[i]);
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
init_rwsem(&found->groups_sem);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
spin_lock_init(&found->lock);
|
2010-05-16 14:46:24 +00:00
|
|
|
found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
|
|
|
|
BTRFS_BLOCK_GROUP_SYSTEM |
|
|
|
|
BTRFS_BLOCK_GROUP_METADATA);
|
2008-03-25 20:50:33 +00:00
|
|
|
found->total_bytes = total_bytes;
|
2010-10-14 18:52:27 +00:00
|
|
|
found->disk_total = total_bytes * factor;
|
2008-03-25 20:50:33 +00:00
|
|
|
found->bytes_used = bytes_used;
|
2010-05-16 14:46:24 +00:00
|
|
|
found->disk_used = bytes_used * factor;
|
2008-03-25 20:50:33 +00:00
|
|
|
found->bytes_pinned = 0;
|
2008-09-26 14:05:48 +00:00
|
|
|
found->bytes_reserved = 0;
|
2008-11-12 19:34:12 +00:00
|
|
|
found->bytes_readonly = 0;
|
2010-05-16 14:46:25 +00:00
|
|
|
found->bytes_may_use = 0;
|
2008-03-25 20:50:33 +00:00
|
|
|
found->full = 0;
|
2008-05-24 18:04:53 +00:00
|
|
|
found->force_alloc = 0;
|
2008-03-25 20:50:33 +00:00
|
|
|
*space_info = found;
|
2009-03-10 16:39:20 +00:00
|
|
|
list_add_rcu(&found->list, &info->space_info);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
atomic_set(&found->caching_threads, 0);
|
2008-03-25 20:50:33 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-04-03 20:29:03 +00:00
|
|
|
static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
|
|
|
|
{
|
|
|
|
u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
|
2008-04-03 20:29:03 +00:00
|
|
|
BTRFS_BLOCK_GROUP_RAID1 |
|
2008-04-16 14:49:51 +00:00
|
|
|
BTRFS_BLOCK_GROUP_RAID10 |
|
2008-04-03 20:29:03 +00:00
|
|
|
BTRFS_BLOCK_GROUP_DUP);
|
2008-04-03 20:29:03 +00:00
|
|
|
if (extra_flags) {
|
|
|
|
if (flags & BTRFS_BLOCK_GROUP_DATA)
|
|
|
|
fs_info->avail_data_alloc_bits |= extra_flags;
|
|
|
|
if (flags & BTRFS_BLOCK_GROUP_METADATA)
|
|
|
|
fs_info->avail_metadata_alloc_bits |= extra_flags;
|
|
|
|
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
|
|
|
|
fs_info->avail_system_alloc_bits |= extra_flags;
|
|
|
|
}
|
|
|
|
}
|
2008-03-25 20:50:33 +00:00
|
|
|
|
2008-11-18 02:11:30 +00:00
|
|
|
u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
|
2008-04-28 19:29:52 +00:00
|
|
|
{
|
2010-12-13 19:56:23 +00:00
|
|
|
/*
|
|
|
|
* we add in the count of missing devices because we want
|
|
|
|
* to make sure that any RAID levels on a degraded FS
|
|
|
|
* continue to be honored.
|
|
|
|
*/
|
|
|
|
u64 num_devices = root->fs_info->fs_devices->rw_devices +
|
|
|
|
root->fs_info->fs_devices->missing_devices;
|
2008-05-07 15:43:44 +00:00
|
|
|
|
|
|
|
if (num_devices == 1)
|
|
|
|
flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
|
|
|
|
if (num_devices < 4)
|
|
|
|
flags &= ~BTRFS_BLOCK_GROUP_RAID10;
|
|
|
|
|
2008-04-28 19:29:52 +00:00
|
|
|
if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
|
|
|
|
(flags & (BTRFS_BLOCK_GROUP_RAID1 |
|
2008-05-07 15:43:44 +00:00
|
|
|
BTRFS_BLOCK_GROUP_RAID10))) {
|
2008-04-28 19:29:52 +00:00
|
|
|
flags &= ~BTRFS_BLOCK_GROUP_DUP;
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
2008-04-28 19:29:52 +00:00
|
|
|
|
|
|
|
if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
|
2008-05-07 15:43:44 +00:00
|
|
|
(flags & BTRFS_BLOCK_GROUP_RAID10)) {
|
2008-04-28 19:29:52 +00:00
|
|
|
flags &= ~BTRFS_BLOCK_GROUP_RAID1;
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
2008-04-28 19:29:52 +00:00
|
|
|
|
|
|
|
if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
|
|
|
|
((flags & BTRFS_BLOCK_GROUP_RAID1) |
|
|
|
|
(flags & BTRFS_BLOCK_GROUP_RAID10) |
|
|
|
|
(flags & BTRFS_BLOCK_GROUP_DUP)))
|
|
|
|
flags &= ~BTRFS_BLOCK_GROUP_RAID0;
|
|
|
|
return flags;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
|
2009-02-20 16:00:09 +00:00
|
|
|
{
|
2010-05-16 14:46:24 +00:00
|
|
|
if (flags & BTRFS_BLOCK_GROUP_DATA)
|
|
|
|
flags |= root->fs_info->avail_data_alloc_bits &
|
|
|
|
root->fs_info->data_alloc_profile;
|
|
|
|
else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
|
|
|
|
flags |= root->fs_info->avail_system_alloc_bits &
|
|
|
|
root->fs_info->system_alloc_profile;
|
|
|
|
else if (flags & BTRFS_BLOCK_GROUP_METADATA)
|
|
|
|
flags |= root->fs_info->avail_metadata_alloc_bits &
|
|
|
|
root->fs_info->metadata_alloc_profile;
|
|
|
|
return btrfs_reduce_alloc_profile(root, flags);
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
btrfs: fix wrong free space information of btrfs
When we store data by raid profile in btrfs with two or more different size
disks, df command shows there is some free space in the filesystem, but the
user can not write any data in fact, df command shows the wrong free space
information of btrfs.
# mkfs.btrfs -d raid1 /dev/sda9 /dev/sda10
# btrfs-show
Label: none uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
Total devices 2 FS bytes used 28.00KB
devid 1 size 5.01GB used 2.03GB path /dev/sda9
devid 2 size 10.00GB used 2.01GB path /dev/sda10
# btrfs device scan /dev/sda9 /dev/sda10
# mount /dev/sda9 /mnt
# dd if=/dev/zero of=tmpfile0 bs=4K count=9999999999
(fill the filesystem)
# sync
# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda9 btrfs 17G 8.6G 5.4G 62% /mnt
# btrfs-show
Label: none uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
Total devices 2 FS bytes used 3.99GB
devid 1 size 5.01GB used 5.01GB path /dev/sda9
devid 2 size 10.00GB used 4.99GB path /dev/sda10
It is because btrfs cannot allocate chunks when one of the pairing disks has
no space, the free space on the other disks can not be used for ever, and should
be subtracted from the total space, but btrfs doesn't subtract this space from
the total. It is strange to the user.
This patch fixes it by calcing the free space that can be used to allocate
chunks.
Implementation:
1. get all the devices free space, and align them by stripe length.
2. sort the devices by the free space.
3. check the free space of the devices,
3.1. if it is not zero, and then check the number of the devices that has
more free space than this device,
if the number of the devices is beyond the min stripe number, the free
space can be used, and add into total free space.
if the number of the devices is below the min stripe number, we can not
use the free space, the check ends.
3.2. if the free space is zero, check the next devices, goto 3.1
This implementation is just likely fake chunk allocation.
After appling this patch, df can show correct space information:
# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda9 btrfs 17G 8.6G 0 100% /mnt
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-01-05 10:07:31 +00:00
|
|
|
u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
|
2009-09-11 20:12:44 +00:00
|
|
|
{
|
2010-05-16 14:46:24 +00:00
|
|
|
u64 flags;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
if (data)
|
|
|
|
flags = BTRFS_BLOCK_GROUP_DATA;
|
|
|
|
else if (root == root->fs_info->chunk_root)
|
|
|
|
flags = BTRFS_BLOCK_GROUP_SYSTEM;
|
2009-09-11 20:12:44 +00:00
|
|
|
else
|
2010-05-16 14:46:24 +00:00
|
|
|
flags = BTRFS_BLOCK_GROUP_METADATA;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
return get_alloc_profile(root, flags);
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
|
|
|
|
{
|
|
|
|
BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
|
2010-05-16 14:46:25 +00:00
|
|
|
BTRFS_BLOCK_GROUP_DATA);
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
/*
|
|
|
|
* This will check the space that the inode allocates from to make sure we have
|
|
|
|
* enough space for bytes.
|
|
|
|
*/
|
2010-05-16 14:48:47 +00:00
|
|
|
int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
|
2009-02-20 16:00:09 +00:00
|
|
|
{
|
|
|
|
struct btrfs_space_info *data_sinfo;
|
2010-05-16 14:48:47 +00:00
|
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
2010-03-19 14:38:13 +00:00
|
|
|
u64 used;
|
2010-06-21 18:48:16 +00:00
|
|
|
int ret = 0, committed = 0, alloc_chunk = 1;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
|
|
|
/* make sure bytes are sectorsize aligned */
|
|
|
|
bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
|
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
if (root == root->fs_info->tree_root) {
|
|
|
|
alloc_chunk = 0;
|
|
|
|
committed = 1;
|
|
|
|
}
|
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
data_sinfo = BTRFS_I(inode)->space_info;
|
2009-09-22 18:45:50 +00:00
|
|
|
if (!data_sinfo)
|
|
|
|
goto alloc;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
again:
|
|
|
|
/* make sure we have enough space to handle the data first */
|
|
|
|
spin_lock(&data_sinfo->lock);
|
2010-05-16 14:49:58 +00:00
|
|
|
used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
|
|
|
|
data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
|
|
|
|
data_sinfo->bytes_may_use;
|
2010-03-19 14:38:13 +00:00
|
|
|
|
|
|
|
if (used + bytes > data_sinfo->total_bytes) {
|
2009-02-20 15:59:53 +00:00
|
|
|
struct btrfs_trans_handle *trans;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
/*
|
|
|
|
* if we don't have enough free bytes in this space then we need
|
|
|
|
* to alloc a new chunk.
|
|
|
|
*/
|
2010-06-21 18:48:16 +00:00
|
|
|
if (!data_sinfo->full && alloc_chunk) {
|
2009-02-20 16:00:09 +00:00
|
|
|
u64 alloc_target;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
data_sinfo->force_alloc = 1;
|
|
|
|
spin_unlock(&data_sinfo->lock);
|
2009-09-22 18:45:50 +00:00
|
|
|
alloc:
|
2009-02-20 16:00:09 +00:00
|
|
|
alloc_target = btrfs_get_alloc_profile(root, 1);
|
2010-05-16 14:48:46 +00:00
|
|
|
trans = btrfs_join_transaction(root, 1);
|
|
|
|
if (IS_ERR(trans))
|
|
|
|
return PTR_ERR(trans);
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
ret = do_chunk_alloc(trans, root->fs_info->extent_root,
|
|
|
|
bytes + 2 * 1024 * 1024,
|
|
|
|
alloc_target, 0);
|
|
|
|
btrfs_end_transaction(trans, root);
|
2011-01-05 10:07:18 +00:00
|
|
|
if (ret < 0) {
|
|
|
|
if (ret != -ENOSPC)
|
|
|
|
return ret;
|
|
|
|
else
|
|
|
|
goto commit_trans;
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2009-09-22 18:45:50 +00:00
|
|
|
if (!data_sinfo) {
|
|
|
|
btrfs_set_inode_space_info(root, inode);
|
|
|
|
data_sinfo = BTRFS_I(inode)->space_info;
|
|
|
|
}
|
2009-02-20 16:00:09 +00:00
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
spin_unlock(&data_sinfo->lock);
|
|
|
|
|
2009-02-20 15:59:53 +00:00
|
|
|
/* commit the current transaction and try again */
|
2011-01-05 10:07:18 +00:00
|
|
|
commit_trans:
|
2009-09-29 22:38:44 +00:00
|
|
|
if (!committed && !root->fs_info->open_ioctl_trans) {
|
2009-02-20 15:59:53 +00:00
|
|
|
committed = 1;
|
|
|
|
trans = btrfs_join_transaction(root, 1);
|
2010-05-16 14:48:46 +00:00
|
|
|
if (IS_ERR(trans))
|
|
|
|
return PTR_ERR(trans);
|
2009-02-20 15:59:53 +00:00
|
|
|
ret = btrfs_commit_transaction(trans, root);
|
|
|
|
if (ret)
|
|
|
|
return ret;
|
|
|
|
goto again;
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-26 15:31:00 +00:00
|
|
|
#if 0 /* I hope we never need this code again, just in case */
|
2010-05-16 14:49:58 +00:00
|
|
|
printk(KERN_ERR "no space left, need %llu, %llu bytes_used, "
|
|
|
|
"%llu bytes_reserved, " "%llu bytes_pinned, "
|
|
|
|
"%llu bytes_readonly, %llu may use %llu total\n",
|
|
|
|
(unsigned long long)bytes,
|
2009-04-21 19:38:29 +00:00
|
|
|
(unsigned long long)data_sinfo->bytes_used,
|
|
|
|
(unsigned long long)data_sinfo->bytes_reserved,
|
|
|
|
(unsigned long long)data_sinfo->bytes_pinned,
|
|
|
|
(unsigned long long)data_sinfo->bytes_readonly,
|
|
|
|
(unsigned long long)data_sinfo->bytes_may_use,
|
|
|
|
(unsigned long long)data_sinfo->total_bytes);
|
2010-05-26 15:31:00 +00:00
|
|
|
#endif
|
2009-02-20 16:00:09 +00:00
|
|
|
return -ENOSPC;
|
|
|
|
}
|
|
|
|
data_sinfo->bytes_may_use += bytes;
|
|
|
|
BTRFS_I(inode)->reserved_bytes += bytes;
|
|
|
|
spin_unlock(&data_sinfo->lock);
|
|
|
|
|
2009-09-11 20:12:44 +00:00
|
|
|
return 0;
|
|
|
|
}
|
2009-02-20 16:00:09 +00:00
|
|
|
|
|
|
|
/*
|
2010-05-16 14:48:47 +00:00
|
|
|
* called when we are clearing an delalloc extent from the
|
|
|
|
* inode's io_tree or there was an error for whatever reason
|
|
|
|
* after calling btrfs_check_data_free_space
|
2009-02-20 16:00:09 +00:00
|
|
|
*/
|
2010-05-16 14:48:47 +00:00
|
|
|
void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
|
2009-10-08 00:44:34 +00:00
|
|
|
{
|
2010-05-16 14:48:47 +00:00
|
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
2009-02-20 16:00:09 +00:00
|
|
|
struct btrfs_space_info *data_sinfo;
|
2009-10-08 00:44:34 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
/* make sure bytes are sectorsize aligned */
|
|
|
|
bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
|
2009-10-08 00:44:34 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
data_sinfo = BTRFS_I(inode)->space_info;
|
|
|
|
spin_lock(&data_sinfo->lock);
|
|
|
|
data_sinfo->bytes_may_use -= bytes;
|
|
|
|
BTRFS_I(inode)->reserved_bytes -= bytes;
|
|
|
|
spin_unlock(&data_sinfo->lock);
|
2009-10-08 00:44:34 +00:00
|
|
|
}
|
|
|
|
|
2009-04-21 21:40:57 +00:00
|
|
|
static void force_metadata_allocation(struct btrfs_fs_info *info)
|
2009-10-08 00:44:34 +00:00
|
|
|
{
|
2009-04-21 21:40:57 +00:00
|
|
|
struct list_head *head = &info->space_info;
|
|
|
|
struct btrfs_space_info *found;
|
2009-10-08 00:44:34 +00:00
|
|
|
|
2009-04-21 21:40:57 +00:00
|
|
|
rcu_read_lock();
|
|
|
|
list_for_each_entry_rcu(found, head, list) {
|
|
|
|
if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
|
|
|
|
found->force_alloc = 1;
|
2009-10-08 00:44:34 +00:00
|
|
|
}
|
2009-04-21 21:40:57 +00:00
|
|
|
rcu_read_unlock();
|
2009-10-08 00:44:34 +00:00
|
|
|
}
|
|
|
|
|
2010-10-26 17:37:56 +00:00
|
|
|
static int should_alloc_chunk(struct btrfs_root *root,
|
|
|
|
struct btrfs_space_info *sinfo, u64 alloc_bytes)
|
2009-10-08 17:34:05 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
|
2010-10-26 17:37:56 +00:00
|
|
|
u64 thresh;
|
2009-10-08 00:44:34 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (sinfo->bytes_used + sinfo->bytes_reserved +
|
|
|
|
alloc_bytes + 256 * 1024 * 1024 < num_bytes)
|
|
|
|
return 0;
|
2009-10-08 00:44:34 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (sinfo->bytes_used + sinfo->bytes_reserved +
|
|
|
|
alloc_bytes < div_factor(num_bytes, 8))
|
|
|
|
return 0;
|
2009-10-08 17:34:05 +00:00
|
|
|
|
2010-10-26 17:37:56 +00:00
|
|
|
thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
|
|
|
|
thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
|
|
|
|
|
|
|
|
if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
|
2010-10-15 19:23:48 +00:00
|
|
|
return 0;
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
return 1;
|
2009-10-08 17:34:05 +00:00
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
static int do_chunk_alloc(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *extent_root, u64 alloc_bytes,
|
2008-05-24 18:04:53 +00:00
|
|
|
u64 flags, int force)
|
2009-09-11 20:12:44 +00:00
|
|
|
{
|
2008-03-24 19:01:59 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
2009-04-21 21:40:57 +00:00
|
|
|
struct btrfs_fs_info *fs_info = extent_root->fs_info;
|
2009-09-11 20:12:44 +00:00
|
|
|
int ret = 0;
|
|
|
|
|
2009-04-21 21:40:57 +00:00
|
|
|
mutex_lock(&fs_info->chunk_mutex);
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2008-11-18 02:11:30 +00:00
|
|
|
flags = btrfs_reduce_alloc_profile(extent_root, flags);
|
2008-04-28 19:29:52 +00:00
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
space_info = __find_space_info(extent_root->fs_info, flags);
|
2008-03-25 20:50:33 +00:00
|
|
|
if (!space_info) {
|
|
|
|
ret = update_space_info(extent_root->fs_info, flags,
|
|
|
|
0, 0, &space_info);
|
|
|
|
BUG_ON(ret);
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
2008-03-24 19:01:59 +00:00
|
|
|
BUG_ON(!space_info);
|
2009-09-11 20:12:44 +00:00
|
|
|
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_lock(&space_info->lock);
|
2009-09-11 20:12:44 +00:00
|
|
|
if (space_info->force_alloc)
|
2008-05-24 18:04:53 +00:00
|
|
|
force = 1;
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
if (space_info->full) {
|
|
|
|
spin_unlock(&space_info->lock);
|
2008-06-25 20:01:30 +00:00
|
|
|
goto out;
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
|
|
|
|
2010-10-26 17:37:56 +00:00
|
|
|
if (!force && !should_alloc_chunk(extent_root, space_info,
|
|
|
|
alloc_bytes)) {
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_unlock(&space_info->lock);
|
2008-06-25 20:01:30 +00:00
|
|
|
goto out;
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_unlock(&space_info->lock);
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-09-16 20:19:09 +00:00
|
|
|
/*
|
|
|
|
* If we have mixed data/metadata chunks we want to make sure we keep
|
|
|
|
* allocating mixed chunks instead of individual chunks.
|
|
|
|
*/
|
|
|
|
if (btrfs_mixed_space_info(space_info))
|
|
|
|
flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
|
|
|
|
|
2009-04-21 21:40:57 +00:00
|
|
|
/*
|
|
|
|
* if we're doing a data chunk, go ahead and make sure that
|
|
|
|
* we keep a reasonable number of metadata chunks allocated in the
|
|
|
|
* FS as well.
|
|
|
|
*/
|
2009-09-11 20:12:44 +00:00
|
|
|
if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
|
2009-04-21 21:40:57 +00:00
|
|
|
fs_info->data_chunk_allocations++;
|
|
|
|
if (!(fs_info->data_chunk_allocations %
|
|
|
|
fs_info->metadata_ratio))
|
|
|
|
force_metadata_allocation(fs_info);
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
|
|
|
|
2008-11-18 02:11:30 +00:00
|
|
|
ret = btrfs_alloc_chunk(trans, extent_root, flags);
|
2009-09-11 20:12:44 +00:00
|
|
|
spin_lock(&space_info->lock);
|
|
|
|
if (ret)
|
2008-03-24 19:01:59 +00:00
|
|
|
space_info->full = 1;
|
2010-05-16 14:46:25 +00:00
|
|
|
else
|
|
|
|
ret = 1;
|
2009-09-11 20:12:44 +00:00
|
|
|
space_info->force_alloc = 0;
|
|
|
|
spin_unlock(&space_info->lock);
|
|
|
|
out:
|
2008-11-12 19:34:12 +00:00
|
|
|
mutex_unlock(&extent_root->fs_info->chunk_mutex);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
return ret;
|
2008-03-24 19:01:59 +00:00
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
|
|
|
/*
|
2010-05-16 14:46:25 +00:00
|
|
|
* shrink metadata reservation for delalloc
|
2009-09-11 20:12:44 +00:00
|
|
|
*/
|
2010-05-16 14:46:25 +00:00
|
|
|
static int shrink_delalloc(struct btrfs_trans_handle *trans,
|
2010-10-15 19:18:40 +00:00
|
|
|
struct btrfs_root *root, u64 to_reclaim, int sync)
|
2010-05-16 14:46:25 +00:00
|
|
|
{
|
2010-05-16 14:48:47 +00:00
|
|
|
struct btrfs_block_rsv *block_rsv;
|
2010-10-15 19:18:40 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
2010-05-16 14:46:25 +00:00
|
|
|
u64 reserved;
|
|
|
|
u64 max_reclaim;
|
|
|
|
u64 reclaimed = 0;
|
2011-01-21 21:10:01 +00:00
|
|
|
long time_left;
|
2010-05-16 14:46:25 +00:00
|
|
|
int pause = 1;
|
2010-10-26 17:40:45 +00:00
|
|
|
int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
|
2011-01-21 21:10:01 +00:00
|
|
|
int loops = 0;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
block_rsv = &root->fs_info->delalloc_block_rsv;
|
2010-10-15 19:18:40 +00:00
|
|
|
space_info = block_rsv->space_info;
|
2010-10-26 17:40:45 +00:00
|
|
|
|
|
|
|
smp_mb();
|
2010-10-15 19:18:40 +00:00
|
|
|
reserved = space_info->bytes_reserved;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
|
|
|
if (reserved == 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
max_reclaim = min(reserved, to_reclaim);
|
|
|
|
|
2011-01-21 21:10:01 +00:00
|
|
|
while (loops < 1024) {
|
2010-10-26 17:40:45 +00:00
|
|
|
/* have the flusher threads jump in and do some IO */
|
|
|
|
smp_mb();
|
|
|
|
nr_pages = min_t(unsigned long, nr_pages,
|
|
|
|
root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
|
|
|
|
writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
|
2010-05-16 14:46:25 +00:00
|
|
|
|
2010-10-15 19:18:40 +00:00
|
|
|
spin_lock(&space_info->lock);
|
2011-01-21 21:10:01 +00:00
|
|
|
if (reserved > space_info->bytes_reserved) {
|
|
|
|
loops = 0;
|
2010-10-15 19:18:40 +00:00
|
|
|
reclaimed += reserved - space_info->bytes_reserved;
|
2011-01-21 21:10:01 +00:00
|
|
|
} else {
|
|
|
|
loops++;
|
|
|
|
}
|
2010-10-15 19:18:40 +00:00
|
|
|
reserved = space_info->bytes_reserved;
|
|
|
|
spin_unlock(&space_info->lock);
|
2010-05-16 14:46:25 +00:00
|
|
|
|
|
|
|
if (reserved == 0 || reclaimed >= max_reclaim)
|
|
|
|
break;
|
|
|
|
|
|
|
|
if (trans && trans->transaction->blocked)
|
|
|
|
return -EAGAIN;
|
2010-10-26 17:40:45 +00:00
|
|
|
|
|
|
|
__set_current_state(TASK_INTERRUPTIBLE);
|
2011-01-21 21:10:01 +00:00
|
|
|
time_left = schedule_timeout(pause);
|
|
|
|
|
|
|
|
/* We were interrupted, exit */
|
|
|
|
if (time_left)
|
|
|
|
break;
|
|
|
|
|
2010-10-26 17:40:45 +00:00
|
|
|
pause <<= 1;
|
|
|
|
if (pause > HZ / 10)
|
|
|
|
pause = HZ / 10;
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
}
|
|
|
|
return reclaimed >= to_reclaim;
|
|
|
|
}
|
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
/*
|
|
|
|
* Retries tells us how many times we've called reserve_metadata_bytes. The
|
|
|
|
* idea is if this is the first call (retries == 0) then we will add to our
|
|
|
|
* reserved count if we can't make the allocation in order to hold our place
|
|
|
|
* while we go and try and free up space. That way for retries > 1 we don't try
|
|
|
|
* and add space, we just check to see if the amount of unused space is >= the
|
|
|
|
* total space, meaning that our reservation is valid.
|
|
|
|
*
|
|
|
|
* However if we don't intend to retry this reservation, pass -1 as retries so
|
|
|
|
* that it short circuits this logic.
|
|
|
|
*/
|
|
|
|
static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_block_rsv *block_rsv,
|
|
|
|
u64 orig_bytes, int flush)
|
2009-09-11 20:12:44 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
struct btrfs_space_info *space_info = block_rsv->space_info;
|
2010-10-15 20:52:49 +00:00
|
|
|
u64 unused;
|
|
|
|
u64 num_bytes = orig_bytes;
|
|
|
|
int retries = 0;
|
|
|
|
int ret = 0;
|
|
|
|
bool reserved = false;
|
2010-10-26 16:52:53 +00:00
|
|
|
bool committed = false;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
again:
|
|
|
|
ret = -ENOSPC;
|
|
|
|
if (reserved)
|
|
|
|
num_bytes = 0;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
spin_lock(&space_info->lock);
|
|
|
|
unused = space_info->bytes_used + space_info->bytes_reserved +
|
|
|
|
space_info->bytes_pinned + space_info->bytes_readonly +
|
|
|
|
space_info->bytes_may_use;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
/*
|
|
|
|
* The idea here is that we've not already over-reserved the block group
|
|
|
|
* then we can go ahead and save our reservation first and then start
|
|
|
|
* flushing if we need to. Otherwise if we've already overcommitted
|
|
|
|
* lets start flushing stuff first and then come back and try to make
|
|
|
|
* our reservation.
|
|
|
|
*/
|
|
|
|
if (unused <= space_info->total_bytes) {
|
2010-11-12 23:17:56 +00:00
|
|
|
unused = space_info->total_bytes - unused;
|
2010-10-15 20:52:49 +00:00
|
|
|
if (unused >= num_bytes) {
|
|
|
|
if (!reserved)
|
|
|
|
space_info->bytes_reserved += orig_bytes;
|
|
|
|
ret = 0;
|
|
|
|
} else {
|
|
|
|
/*
|
|
|
|
* Ok set num_bytes to orig_bytes since we aren't
|
|
|
|
* overocmmitted, this way we only try and reclaim what
|
|
|
|
* we need.
|
|
|
|
*/
|
|
|
|
num_bytes = orig_bytes;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
/*
|
|
|
|
* Ok we're over committed, set num_bytes to the overcommitted
|
|
|
|
* amount plus the amount of bytes that we need for this
|
|
|
|
* reservation.
|
|
|
|
*/
|
|
|
|
num_bytes = unused - space_info->total_bytes +
|
|
|
|
(orig_bytes * (retries + 1));
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
/*
|
|
|
|
* Couldn't make our reservation, save our place so while we're trying
|
|
|
|
* to reclaim space we can actually use it instead of somebody else
|
|
|
|
* stealing it from us.
|
|
|
|
*/
|
|
|
|
if (ret && !reserved) {
|
|
|
|
space_info->bytes_reserved += orig_bytes;
|
|
|
|
reserved = true;
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
spin_unlock(&space_info->lock);
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
if (!ret)
|
|
|
|
return 0;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
if (!flush)
|
|
|
|
goto out;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
/*
|
|
|
|
* We do synchronous shrinking since we don't actually unreserve
|
|
|
|
* metadata until after the IO is completed.
|
|
|
|
*/
|
|
|
|
ret = shrink_delalloc(trans, root, num_bytes, 1);
|
|
|
|
if (ret > 0)
|
|
|
|
return 0;
|
|
|
|
else if (ret < 0)
|
|
|
|
goto out;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
/*
|
|
|
|
* So if we were overcommitted it's possible that somebody else flushed
|
|
|
|
* out enough space and we simply didn't have enough space to reclaim,
|
|
|
|
* so go back around and try again.
|
|
|
|
*/
|
|
|
|
if (retries < 2) {
|
|
|
|
retries++;
|
|
|
|
goto again;
|
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
|
|
|
|
spin_lock(&space_info->lock);
|
2010-10-15 20:52:49 +00:00
|
|
|
/*
|
|
|
|
* Not enough space to be reclaimed, don't bother committing the
|
|
|
|
* transaction.
|
|
|
|
*/
|
|
|
|
if (space_info->bytes_pinned < orig_bytes)
|
|
|
|
ret = -ENOSPC;
|
|
|
|
spin_unlock(&space_info->lock);
|
|
|
|
if (ret)
|
|
|
|
goto out;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
ret = -EAGAIN;
|
2010-10-26 16:52:53 +00:00
|
|
|
if (trans || committed)
|
2010-10-15 20:52:49 +00:00
|
|
|
goto out;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
ret = -ENOSPC;
|
|
|
|
trans = btrfs_join_transaction(root, 1);
|
|
|
|
if (IS_ERR(trans))
|
|
|
|
goto out;
|
|
|
|
ret = btrfs_commit_transaction(trans, root);
|
2010-10-26 16:52:53 +00:00
|
|
|
if (!ret) {
|
|
|
|
trans = NULL;
|
|
|
|
committed = true;
|
2010-10-15 20:52:49 +00:00
|
|
|
goto again;
|
2010-10-26 16:52:53 +00:00
|
|
|
}
|
2010-10-15 20:52:49 +00:00
|
|
|
|
|
|
|
out:
|
|
|
|
if (reserved) {
|
|
|
|
spin_lock(&space_info->lock);
|
|
|
|
space_info->bytes_reserved -= orig_bytes;
|
|
|
|
spin_unlock(&space_info->lock);
|
2010-05-16 14:46:25 +00:00
|
|
|
}
|
2009-02-20 15:59:53 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_block_rsv *block_rsv;
|
|
|
|
if (root->ref_cows)
|
|
|
|
block_rsv = trans->block_rsv;
|
|
|
|
else
|
|
|
|
block_rsv = root->block_rsv;
|
|
|
|
|
|
|
|
if (!block_rsv)
|
|
|
|
block_rsv = &root->fs_info->empty_block_rsv;
|
|
|
|
|
|
|
|
return block_rsv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
|
|
|
|
u64 num_bytes)
|
|
|
|
{
|
|
|
|
int ret = -ENOSPC;
|
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
if (block_rsv->reserved >= num_bytes) {
|
|
|
|
block_rsv->reserved -= num_bytes;
|
|
|
|
if (block_rsv->reserved < block_rsv->size)
|
|
|
|
block_rsv->full = 0;
|
|
|
|
ret = 0;
|
|
|
|
}
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
|
|
|
|
u64 num_bytes, int update_size)
|
|
|
|
{
|
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
block_rsv->reserved += num_bytes;
|
|
|
|
if (update_size)
|
|
|
|
block_rsv->size += num_bytes;
|
|
|
|
else if (block_rsv->reserved >= block_rsv->size)
|
|
|
|
block_rsv->full = 1;
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
|
|
|
|
struct btrfs_block_rsv *dest, u64 num_bytes)
|
|
|
|
{
|
|
|
|
struct btrfs_space_info *space_info = block_rsv->space_info;
|
|
|
|
|
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
if (num_bytes == (u64)-1)
|
|
|
|
num_bytes = block_rsv->size;
|
|
|
|
block_rsv->size -= num_bytes;
|
|
|
|
if (block_rsv->reserved >= block_rsv->size) {
|
|
|
|
num_bytes = block_rsv->reserved - block_rsv->size;
|
|
|
|
block_rsv->reserved = block_rsv->size;
|
|
|
|
block_rsv->full = 1;
|
|
|
|
} else {
|
|
|
|
num_bytes = 0;
|
|
|
|
}
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
|
|
|
|
if (num_bytes > 0) {
|
|
|
|
if (dest) {
|
2011-01-24 21:43:19 +00:00
|
|
|
spin_lock(&dest->lock);
|
|
|
|
if (!dest->full) {
|
|
|
|
u64 bytes_to_add;
|
|
|
|
|
|
|
|
bytes_to_add = dest->size - dest->reserved;
|
|
|
|
bytes_to_add = min(num_bytes, bytes_to_add);
|
|
|
|
dest->reserved += bytes_to_add;
|
|
|
|
if (dest->reserved >= dest->size)
|
|
|
|
dest->full = 1;
|
|
|
|
num_bytes -= bytes_to_add;
|
|
|
|
}
|
|
|
|
spin_unlock(&dest->lock);
|
|
|
|
}
|
|
|
|
if (num_bytes) {
|
2010-05-16 14:46:25 +00:00
|
|
|
spin_lock(&space_info->lock);
|
|
|
|
space_info->bytes_reserved -= num_bytes;
|
|
|
|
spin_unlock(&space_info->lock);
|
2009-02-20 15:59:53 +00:00
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
}
|
2009-02-20 15:59:53 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
|
|
|
|
struct btrfs_block_rsv *dst, u64 num_bytes)
|
|
|
|
{
|
|
|
|
int ret;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = block_rsv_use_bytes(src, num_bytes);
|
|
|
|
if (ret)
|
|
|
|
return ret;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
block_rsv_add_bytes(dst, num_bytes, 1);
|
2009-09-11 20:12:44 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
|
2009-09-11 20:12:44 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
memset(rsv, 0, sizeof(*rsv));
|
|
|
|
spin_lock_init(&rsv->lock);
|
|
|
|
atomic_set(&rsv->usage, 1);
|
|
|
|
rsv->priority = 6;
|
|
|
|
INIT_LIST_HEAD(&rsv->list);
|
|
|
|
}
|
|
|
|
|
|
|
|
struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_block_rsv *block_rsv;
|
|
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
|
|
|
|
if (!block_rsv)
|
|
|
|
return NULL;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
btrfs_init_block_rsv(block_rsv);
|
|
|
|
block_rsv->space_info = __find_space_info(fs_info,
|
|
|
|
BTRFS_BLOCK_GROUP_METADATA);
|
|
|
|
return block_rsv;
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
void btrfs_free_block_rsv(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_rsv *rsv)
|
|
|
|
{
|
|
|
|
if (rsv && atomic_dec_and_test(&rsv->usage)) {
|
|
|
|
btrfs_block_rsv_release(root, rsv, (u64)-1);
|
|
|
|
if (!rsv->durable)
|
|
|
|
kfree(rsv);
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2010-05-16 14:46:25 +00:00
|
|
|
* make the block_rsv struct be able to capture freed space.
|
|
|
|
* the captured space will re-add to the the block_rsv struct
|
|
|
|
* after transaction commit
|
2009-09-11 20:12:44 +00:00
|
|
|
*/
|
2010-05-16 14:46:25 +00:00
|
|
|
void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
|
|
|
|
struct btrfs_block_rsv *block_rsv)
|
2009-09-11 20:12:44 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
block_rsv->durable = 1;
|
|
|
|
mutex_lock(&fs_info->durable_block_rsv_mutex);
|
|
|
|
list_add_tail(&block_rsv->list, &fs_info->durable_block_rsv_list);
|
|
|
|
mutex_unlock(&fs_info->durable_block_rsv_mutex);
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_block_rsv *block_rsv,
|
2010-10-15 20:52:49 +00:00
|
|
|
u64 num_bytes)
|
2010-05-16 14:46:25 +00:00
|
|
|
{
|
|
|
|
int ret;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (num_bytes == 0)
|
|
|
|
return 0;
|
2010-10-15 20:52:49 +00:00
|
|
|
|
|
|
|
ret = reserve_metadata_bytes(trans, root, block_rsv, num_bytes, 1);
|
2010-05-16 14:46:25 +00:00
|
|
|
if (!ret) {
|
|
|
|
block_rsv_add_bytes(block_rsv, num_bytes, 1);
|
|
|
|
return 0;
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
return ret;
|
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_block_rsv *block_rsv,
|
|
|
|
u64 min_reserved, int min_factor)
|
|
|
|
{
|
|
|
|
u64 num_bytes = 0;
|
|
|
|
int commit_trans = 0;
|
|
|
|
int ret = -ENOSPC;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (!block_rsv)
|
|
|
|
return 0;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
if (min_factor > 0)
|
|
|
|
num_bytes = div_factor(block_rsv->size, min_factor);
|
|
|
|
if (min_reserved > num_bytes)
|
|
|
|
num_bytes = min_reserved;
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (block_rsv->reserved >= num_bytes) {
|
|
|
|
ret = 0;
|
|
|
|
} else {
|
|
|
|
num_bytes -= block_rsv->reserved;
|
|
|
|
if (block_rsv->durable &&
|
|
|
|
block_rsv->freed[0] + block_rsv->freed[1] >= num_bytes)
|
|
|
|
commit_trans = 1;
|
|
|
|
}
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
if (!ret)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (block_rsv->refill_used) {
|
2010-10-15 20:52:49 +00:00
|
|
|
ret = reserve_metadata_bytes(trans, root, block_rsv,
|
|
|
|
num_bytes, 0);
|
2010-05-16 14:46:25 +00:00
|
|
|
if (!ret) {
|
|
|
|
block_rsv_add_bytes(block_rsv, num_bytes, 0);
|
|
|
|
return 0;
|
2009-02-20 15:59:53 +00:00
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (commit_trans) {
|
|
|
|
if (trans)
|
|
|
|
return -EAGAIN;
|
|
|
|
|
|
|
|
trans = btrfs_join_transaction(root, 1);
|
|
|
|
BUG_ON(IS_ERR(trans));
|
|
|
|
ret = btrfs_commit_transaction(trans, root);
|
|
|
|
return 0;
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
2009-09-11 20:12:44 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
return -ENOSPC;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
|
|
|
|
struct btrfs_block_rsv *dst_rsv,
|
|
|
|
u64 num_bytes)
|
|
|
|
{
|
|
|
|
return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
|
|
|
|
}
|
|
|
|
|
|
|
|
void btrfs_block_rsv_release(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_rsv *block_rsv,
|
|
|
|
u64 num_bytes)
|
|
|
|
{
|
|
|
|
struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
|
|
|
|
if (global_rsv->full || global_rsv == block_rsv ||
|
|
|
|
block_rsv->space_info != global_rsv->space_info)
|
|
|
|
global_rsv = NULL;
|
|
|
|
block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2010-05-16 14:49:58 +00:00
|
|
|
* helper to calculate size of global block reservation.
|
|
|
|
* the desired value is sum of space used by extent tree,
|
|
|
|
* checksum tree and root tree
|
2009-02-20 16:00:09 +00:00
|
|
|
*/
|
2010-05-16 14:49:58 +00:00
|
|
|
static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
|
2009-02-20 16:00:09 +00:00
|
|
|
{
|
2010-05-16 14:49:58 +00:00
|
|
|
struct btrfs_space_info *sinfo;
|
|
|
|
u64 num_bytes;
|
|
|
|
u64 meta_used;
|
|
|
|
u64 data_used;
|
|
|
|
int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
|
|
|
|
#if 0
|
|
|
|
/*
|
|
|
|
* per tree used space accounting can be inaccuracy, so we
|
|
|
|
* can't rely on it.
|
|
|
|
*/
|
|
|
|
spin_lock(&fs_info->extent_root->accounting_lock);
|
|
|
|
num_bytes = btrfs_root_used(&fs_info->extent_root->root_item);
|
|
|
|
spin_unlock(&fs_info->extent_root->accounting_lock);
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
spin_lock(&fs_info->csum_root->accounting_lock);
|
|
|
|
num_bytes += btrfs_root_used(&fs_info->csum_root->root_item);
|
|
|
|
spin_unlock(&fs_info->csum_root->accounting_lock);
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
spin_lock(&fs_info->tree_root->accounting_lock);
|
|
|
|
num_bytes += btrfs_root_used(&fs_info->tree_root->root_item);
|
|
|
|
spin_unlock(&fs_info->tree_root->accounting_lock);
|
|
|
|
#endif
|
|
|
|
sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
|
|
|
|
spin_lock(&sinfo->lock);
|
|
|
|
data_used = sinfo->bytes_used;
|
|
|
|
spin_unlock(&sinfo->lock);
|
2009-09-22 18:45:50 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
|
|
|
|
spin_lock(&sinfo->lock);
|
2010-10-15 19:13:32 +00:00
|
|
|
if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
|
|
|
|
data_used = 0;
|
2010-05-16 14:49:58 +00:00
|
|
|
meta_used = sinfo->bytes_used;
|
|
|
|
spin_unlock(&sinfo->lock);
|
2010-03-19 14:38:13 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
|
|
|
|
csum_size * 2;
|
|
|
|
num_bytes += div64_u64(data_used + meta_used, 50);
|
2009-02-20 15:59:53 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
if (num_bytes * 3 > meta_used)
|
|
|
|
num_bytes = div64_u64(meta_used, 3);
|
2010-03-19 14:38:13 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
|
|
|
|
}
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
|
|
|
|
{
|
|
|
|
struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
|
|
|
|
struct btrfs_space_info *sinfo = block_rsv->space_info;
|
|
|
|
u64 num_bytes;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
num_bytes = calc_global_metadata_size(fs_info);
|
2009-09-22 18:45:50 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
spin_lock(&sinfo->lock);
|
2009-02-20 15:59:53 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
block_rsv->size = num_bytes;
|
2009-02-20 15:59:53 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
|
2010-10-15 19:13:32 +00:00
|
|
|
sinfo->bytes_reserved + sinfo->bytes_readonly +
|
|
|
|
sinfo->bytes_may_use;
|
2010-05-16 14:49:58 +00:00
|
|
|
|
|
|
|
if (sinfo->total_bytes > num_bytes) {
|
|
|
|
num_bytes = sinfo->total_bytes - num_bytes;
|
|
|
|
block_rsv->reserved += num_bytes;
|
|
|
|
sinfo->bytes_reserved += num_bytes;
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
if (block_rsv->reserved >= block_rsv->size) {
|
|
|
|
num_bytes = block_rsv->reserved - block_rsv->size;
|
|
|
|
sinfo->bytes_reserved -= num_bytes;
|
|
|
|
block_rsv->reserved = block_rsv->size;
|
|
|
|
block_rsv->full = 1;
|
|
|
|
}
|
|
|
|
#if 0
|
|
|
|
printk(KERN_INFO"global block rsv size %llu reserved %llu\n",
|
|
|
|
block_rsv->size, block_rsv->reserved);
|
|
|
|
#endif
|
|
|
|
spin_unlock(&sinfo->lock);
|
|
|
|
spin_unlock(&block_rsv->lock);
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
|
2009-02-20 16:00:09 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
|
|
|
|
fs_info->chunk_block_rsv.space_info = space_info;
|
|
|
|
fs_info->chunk_block_rsv.priority = 10;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
|
2010-05-16 14:49:58 +00:00
|
|
|
fs_info->global_block_rsv.space_info = space_info;
|
|
|
|
fs_info->global_block_rsv.priority = 10;
|
|
|
|
fs_info->global_block_rsv.refill_used = 1;
|
|
|
|
fs_info->delalloc_block_rsv.space_info = space_info;
|
2010-05-16 14:46:25 +00:00
|
|
|
fs_info->trans_block_rsv.space_info = space_info;
|
|
|
|
fs_info->empty_block_rsv.space_info = space_info;
|
|
|
|
fs_info->empty_block_rsv.priority = 10;
|
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
|
|
|
|
fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
|
|
|
|
fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
|
|
|
|
fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
|
2010-05-16 14:46:25 +00:00
|
|
|
fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
|
2010-05-16 14:49:58 +00:00
|
|
|
|
|
|
|
btrfs_add_durable_block_rsv(fs_info, &fs_info->global_block_rsv);
|
|
|
|
|
|
|
|
btrfs_add_durable_block_rsv(fs_info, &fs_info->delalloc_block_rsv);
|
|
|
|
|
|
|
|
update_global_block_rsv(fs_info);
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
|
2009-02-20 16:00:09 +00:00
|
|
|
{
|
2010-05-16 14:49:58 +00:00
|
|
|
block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
|
|
|
|
WARN_ON(fs_info->delalloc_block_rsv.size > 0);
|
|
|
|
WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
|
|
|
|
WARN_ON(fs_info->trans_block_rsv.size > 0);
|
|
|
|
WARN_ON(fs_info->trans_block_rsv.reserved > 0);
|
|
|
|
WARN_ON(fs_info->chunk_block_rsv.size > 0);
|
|
|
|
WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
|
2010-05-16 14:46:25 +00:00
|
|
|
}
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
static u64 calc_trans_metadata_size(struct btrfs_root *root, int num_items)
|
|
|
|
{
|
|
|
|
return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
|
|
|
|
3 * num_items;
|
|
|
|
}
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
2010-10-15 20:52:49 +00:00
|
|
|
int num_items)
|
2010-05-16 14:48:46 +00:00
|
|
|
{
|
|
|
|
u64 num_bytes;
|
|
|
|
int ret;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
if (num_items == 0 || root->fs_info->chunk_root == root)
|
|
|
|
return 0;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
num_bytes = calc_trans_metadata_size(root, num_items);
|
|
|
|
ret = btrfs_block_rsv_add(trans, root, &root->fs_info->trans_block_rsv,
|
2010-10-15 20:52:49 +00:00
|
|
|
num_bytes);
|
2010-05-16 14:48:46 +00:00
|
|
|
if (!ret) {
|
|
|
|
trans->bytes_reserved += num_bytes;
|
|
|
|
trans->block_rsv = &root->fs_info->trans_block_rsv;
|
|
|
|
}
|
|
|
|
return ret;
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root)
|
2009-02-20 16:00:09 +00:00
|
|
|
{
|
2010-05-16 14:48:46 +00:00
|
|
|
if (!trans->bytes_reserved)
|
|
|
|
return;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
|
|
|
|
btrfs_block_rsv_release(root, trans->block_rsv,
|
|
|
|
trans->bytes_reserved);
|
|
|
|
trans->bytes_reserved = 0;
|
|
|
|
}
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
|
|
|
|
struct inode *inode)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
|
|
|
struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
|
|
|
|
struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* one for deleting orphan item, one for updating inode and
|
|
|
|
* two for calling btrfs_truncate_inode_items.
|
|
|
|
*
|
|
|
|
* btrfs_truncate_inode_items is a delete operation, it frees
|
|
|
|
* more space than it uses in most cases. So two units of
|
|
|
|
* metadata space should be enough for calling it many times.
|
|
|
|
* If all of the metadata space is used, we can commit
|
|
|
|
* transaction and use space it freed.
|
|
|
|
*/
|
|
|
|
u64 num_bytes = calc_trans_metadata_size(root, 4);
|
|
|
|
return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
|
2009-02-20 16:00:09 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
void btrfs_orphan_release_metadata(struct inode *inode)
|
2009-04-21 21:40:57 +00:00
|
|
|
{
|
2010-05-16 14:49:58 +00:00
|
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
|
|
|
u64 num_bytes = calc_trans_metadata_size(root, 4);
|
|
|
|
btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
|
|
|
|
}
|
2009-04-21 21:40:57 +00:00
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_pending_snapshot *pending)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = pending->root;
|
|
|
|
struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
|
|
|
|
struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
|
|
|
|
/*
|
|
|
|
* two for root back/forward refs, two for directory entries
|
|
|
|
* and one for root of the snapshot.
|
|
|
|
*/
|
|
|
|
u64 num_bytes = calc_trans_metadata_size(root, 5);
|
|
|
|
dst_rsv->space_info = src_rsv->space_info;
|
|
|
|
return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
|
2009-04-21 21:40:57 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes)
|
2008-03-24 19:01:59 +00:00
|
|
|
{
|
2010-05-16 14:48:47 +00:00
|
|
|
return num_bytes >>= 3;
|
|
|
|
}
|
2008-11-12 19:34:12 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
|
|
|
struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
|
|
|
|
u64 to_reserve;
|
|
|
|
int nr_extents;
|
|
|
|
int ret;
|
2008-03-24 19:01:59 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
if (btrfs_transaction_in_commit(root->fs_info))
|
|
|
|
schedule_timeout(1);
|
2008-04-28 19:29:52 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
num_bytes = ALIGN(num_bytes, root->sectorsize);
|
2010-10-15 20:52:49 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
spin_lock(&BTRFS_I(inode)->accounting_lock);
|
|
|
|
nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents) + 1;
|
|
|
|
if (nr_extents > BTRFS_I(inode)->reserved_extents) {
|
|
|
|
nr_extents -= BTRFS_I(inode)->reserved_extents;
|
|
|
|
to_reserve = calc_trans_metadata_size(root, nr_extents);
|
|
|
|
} else {
|
|
|
|
nr_extents = 0;
|
|
|
|
to_reserve = 0;
|
2008-03-25 20:50:33 +00:00
|
|
|
}
|
2010-10-15 20:52:49 +00:00
|
|
|
spin_unlock(&BTRFS_I(inode)->accounting_lock);
|
2008-03-24 19:01:59 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
to_reserve += calc_csum_metadata_size(inode, num_bytes);
|
2010-10-15 20:52:49 +00:00
|
|
|
ret = reserve_metadata_bytes(NULL, root, block_rsv, to_reserve, 1);
|
|
|
|
if (ret)
|
2010-05-16 14:48:47 +00:00
|
|
|
return ret;
|
2008-03-24 19:01:59 +00:00
|
|
|
|
2010-10-15 20:52:49 +00:00
|
|
|
spin_lock(&BTRFS_I(inode)->accounting_lock);
|
2010-05-16 14:48:47 +00:00
|
|
|
BTRFS_I(inode)->reserved_extents += nr_extents;
|
|
|
|
atomic_inc(&BTRFS_I(inode)->outstanding_extents);
|
|
|
|
spin_unlock(&BTRFS_I(inode)->accounting_lock);
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
block_rsv_add_bytes(block_rsv, to_reserve, 1);
|
|
|
|
|
|
|
|
if (block_rsv->size > 512 * 1024 * 1024)
|
2010-10-15 19:18:40 +00:00
|
|
|
shrink_delalloc(NULL, root, to_reserve, 0);
|
2010-05-16 14:48:47 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
|
|
|
u64 to_free;
|
|
|
|
int nr_extents;
|
|
|
|
|
|
|
|
num_bytes = ALIGN(num_bytes, root->sectorsize);
|
|
|
|
atomic_dec(&BTRFS_I(inode)->outstanding_extents);
|
|
|
|
|
|
|
|
spin_lock(&BTRFS_I(inode)->accounting_lock);
|
|
|
|
nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents);
|
|
|
|
if (nr_extents < BTRFS_I(inode)->reserved_extents) {
|
|
|
|
nr_extents = BTRFS_I(inode)->reserved_extents - nr_extents;
|
|
|
|
BTRFS_I(inode)->reserved_extents -= nr_extents;
|
|
|
|
} else {
|
|
|
|
nr_extents = 0;
|
2009-04-21 21:40:57 +00:00
|
|
|
}
|
2010-05-16 14:48:47 +00:00
|
|
|
spin_unlock(&BTRFS_I(inode)->accounting_lock);
|
2009-04-21 21:40:57 +00:00
|
|
|
|
2010-05-16 14:48:47 +00:00
|
|
|
to_free = calc_csum_metadata_size(inode, num_bytes);
|
|
|
|
if (nr_extents > 0)
|
|
|
|
to_free += calc_trans_metadata_size(root, nr_extents);
|
|
|
|
|
|
|
|
btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
|
|
|
|
to_free);
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = btrfs_check_data_free_space(inode, num_bytes);
|
2009-01-06 02:25:51 +00:00
|
|
|
if (ret)
|
2010-05-16 14:48:47 +00:00
|
|
|
return ret;
|
|
|
|
|
|
|
|
ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
|
|
|
|
if (ret) {
|
|
|
|
btrfs_free_reserved_data_space(inode, num_bytes);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
|
|
|
|
{
|
|
|
|
btrfs_delalloc_release_metadata(inode, num_bytes);
|
|
|
|
btrfs_free_reserved_data_space(inode, num_bytes);
|
2008-03-24 19:01:59 +00:00
|
|
|
}
|
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
static int update_block_group(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
2010-05-16 14:46:25 +00:00
|
|
|
u64 bytenr, u64 num_bytes, int alloc)
|
2007-04-26 20:46:15 +00:00
|
|
|
{
|
2010-06-21 18:48:16 +00:00
|
|
|
struct btrfs_block_group_cache *cache = NULL;
|
2007-04-26 20:46:15 +00:00
|
|
|
struct btrfs_fs_info *info = root->fs_info;
|
2007-10-15 20:15:53 +00:00
|
|
|
u64 total = num_bytes;
|
2007-04-26 20:46:15 +00:00
|
|
|
u64 old_val;
|
2007-10-15 20:15:53 +00:00
|
|
|
u64 byte_in_group;
|
2010-06-21 18:48:16 +00:00
|
|
|
int factor;
|
2007-05-08 00:03:49 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
/* block accounting for super block */
|
|
|
|
spin_lock(&info->delalloc_lock);
|
|
|
|
old_val = btrfs_super_bytes_used(&info->super_copy);
|
|
|
|
if (alloc)
|
|
|
|
old_val += num_bytes;
|
|
|
|
else
|
|
|
|
old_val -= num_bytes;
|
|
|
|
btrfs_set_super_bytes_used(&info->super_copy, old_val);
|
|
|
|
spin_unlock(&info->delalloc_lock);
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (total) {
|
2007-10-15 20:15:53 +00:00
|
|
|
cache = btrfs_lookup_block_group(info, bytenr);
|
2008-11-12 19:19:50 +00:00
|
|
|
if (!cache)
|
2007-04-26 20:46:15 +00:00
|
|
|
return -1;
|
2010-05-16 14:46:24 +00:00
|
|
|
if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID10))
|
|
|
|
factor = 2;
|
|
|
|
else
|
|
|
|
factor = 1;
|
2010-08-25 20:54:15 +00:00
|
|
|
/*
|
|
|
|
* If this block group has free space cache written out, we
|
|
|
|
* need to make sure to load it if we are removing space. This
|
|
|
|
* is because we need the unpinning stage to actually add the
|
|
|
|
* space back to the block group, otherwise we will leak space.
|
|
|
|
*/
|
|
|
|
if (!alloc && cache->cached == BTRFS_CACHE_NO)
|
2010-12-08 14:15:11 +00:00
|
|
|
cache_block_group(cache, trans, NULL, 1);
|
2010-06-21 18:48:16 +00:00
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
byte_in_group = bytenr - cache->key.objectid;
|
|
|
|
WARN_ON(byte_in_group > cache->key.offset);
|
2007-04-26 20:46:15 +00:00
|
|
|
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_lock(&cache->space_info->lock);
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_lock(&cache->lock);
|
2010-06-21 18:48:16 +00:00
|
|
|
|
|
|
|
if (btrfs_super_cache_generation(&info->super_copy) != 0 &&
|
|
|
|
cache->disk_cache_state < BTRFS_DC_CLEAR)
|
|
|
|
cache->disk_cache_state = BTRFS_DC_CLEAR;
|
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
cache->dirty = 1;
|
2007-04-26 20:46:15 +00:00
|
|
|
old_val = btrfs_block_group_used(&cache->item);
|
2007-10-15 20:15:53 +00:00
|
|
|
num_bytes = min(total, cache->key.offset - byte_in_group);
|
2007-04-27 14:08:34 +00:00
|
|
|
if (alloc) {
|
2007-10-15 20:15:53 +00:00
|
|
|
old_val += num_bytes;
|
2009-09-11 20:11:19 +00:00
|
|
|
btrfs_set_block_group_used(&cache->item, old_val);
|
|
|
|
cache->reserved -= num_bytes;
|
|
|
|
cache->space_info->bytes_reserved -= num_bytes;
|
2010-05-16 14:46:24 +00:00
|
|
|
cache->space_info->bytes_used += num_bytes;
|
|
|
|
cache->space_info->disk_used += num_bytes * factor;
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_unlock(&cache->lock);
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_unlock(&cache->space_info->lock);
|
2007-04-27 14:08:34 +00:00
|
|
|
} else {
|
2007-10-15 20:15:53 +00:00
|
|
|
old_val -= num_bytes;
|
2008-07-23 03:06:41 +00:00
|
|
|
btrfs_set_block_group_used(&cache->item, old_val);
|
2010-05-16 14:46:25 +00:00
|
|
|
cache->pinned += num_bytes;
|
|
|
|
cache->space_info->bytes_pinned += num_bytes;
|
2008-03-24 19:01:59 +00:00
|
|
|
cache->space_info->bytes_used -= num_bytes;
|
2010-05-16 14:46:24 +00:00
|
|
|
cache->space_info->disk_used -= num_bytes * factor;
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_unlock(&cache->lock);
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
spin_unlock(&cache->space_info->lock);
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
set_extent_dirty(info->pinned_extents,
|
|
|
|
bytenr, bytenr + num_bytes - 1,
|
|
|
|
GFP_NOFS | __GFP_NOFAIL);
|
2007-04-27 14:08:34 +00:00
|
|
|
}
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(cache);
|
2007-10-15 20:15:53 +00:00
|
|
|
total -= num_bytes;
|
|
|
|
bytenr += num_bytes;
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
2008-03-24 19:01:59 +00:00
|
|
|
|
2008-05-07 15:43:44 +00:00
|
|
|
static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
|
|
|
|
{
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_block_group_cache *cache;
|
2008-12-11 21:30:39 +00:00
|
|
|
u64 bytenr;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
|
|
|
cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
|
|
|
|
if (!cache)
|
2008-05-07 15:43:44 +00:00
|
|
|
return 0;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2008-12-11 21:30:39 +00:00
|
|
|
bytenr = cache->key.objectid;
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(cache);
|
2008-12-11 21:30:39 +00:00
|
|
|
|
|
|
|
return bytenr;
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
static int pin_down_extent(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *cache,
|
|
|
|
u64 bytenr, u64 num_bytes, int reserved)
|
2007-11-16 19:57:08 +00:00
|
|
|
{
|
2009-09-11 20:11:19 +00:00
|
|
|
spin_lock(&cache->space_info->lock);
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
cache->pinned += num_bytes;
|
|
|
|
cache->space_info->bytes_pinned += num_bytes;
|
|
|
|
if (reserved) {
|
|
|
|
cache->reserved -= num_bytes;
|
|
|
|
cache->space_info->bytes_reserved -= num_bytes;
|
|
|
|
}
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
spin_unlock(&cache->space_info->lock);
|
Btrfs: change how we unpin extents
We are racy with async block caching and unpinning extents. This patch makes
things much less complicated by only unpinning the extent if the block group is
cached. We check the block_group->cached var under the block_group->lock spin
lock. If it is set to BTRFS_CACHE_FINISHED then we update the pinned counters,
and unpin the extent and add the free space back. If it is not set to this, we
start the caching of the block group so the next time we unpin extents we can
unpin the extent. This keeps us from racing with the async caching threads,
lets us kill the fs wide async thread counter, and keeps us from having to set
DELALLOC bits for every extent we hit if there are caching kthreads going.
One thing that needed to be changed was btrfs_free_super_mirror_extents. Now
instead of just looking for LOCKED extents, we also look for DIRTY extents,
since we could have left some extents pinned in the previous transaction that
will never get freed now that we are unmounting, which would cause us to leak
memory. So btrfs_free_super_mirror_extents has been changed to
btrfs_free_pinned_extents, and it will clear the extents locked for the super
mirror, and any remaining pinned extents that may be present. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-27 17:57:01 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
set_extent_dirty(root->fs_info->pinned_extents, bytenr,
|
|
|
|
bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
|
|
|
|
return 0;
|
|
|
|
}
|
Btrfs: change how we unpin extents
We are racy with async block caching and unpinning extents. This patch makes
things much less complicated by only unpinning the extent if the block group is
cached. We check the block_group->cached var under the block_group->lock spin
lock. If it is set to BTRFS_CACHE_FINISHED then we update the pinned counters,
and unpin the extent and add the free space back. If it is not set to this, we
start the caching of the block group so the next time we unpin extents we can
unpin the extent. This keeps us from racing with the async caching threads,
lets us kill the fs wide async thread counter, and keeps us from having to set
DELALLOC bits for every extent we hit if there are caching kthreads going.
One thing that needed to be changed was btrfs_free_super_mirror_extents. Now
instead of just looking for LOCKED extents, we also look for DIRTY extents,
since we could have left some extents pinned in the previous transaction that
will never get freed now that we are unmounting, which would cause us to leak
memory. So btrfs_free_super_mirror_extents has been changed to
btrfs_free_pinned_extents, and it will clear the extents locked for the super
mirror, and any remaining pinned extents that may be present. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-27 17:57:01 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
/*
|
|
|
|
* this function must be called within transaction
|
|
|
|
*/
|
|
|
|
int btrfs_pin_extent(struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, int reserved)
|
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *cache;
|
Btrfs: change how we unpin extents
We are racy with async block caching and unpinning extents. This patch makes
things much less complicated by only unpinning the extent if the block group is
cached. We check the block_group->cached var under the block_group->lock spin
lock. If it is set to BTRFS_CACHE_FINISHED then we update the pinned counters,
and unpin the extent and add the free space back. If it is not set to this, we
start the caching of the block group so the next time we unpin extents we can
unpin the extent. This keeps us from racing with the async caching threads,
lets us kill the fs wide async thread counter, and keeps us from having to set
DELALLOC bits for every extent we hit if there are caching kthreads going.
One thing that needed to be changed was btrfs_free_super_mirror_extents. Now
instead of just looking for LOCKED extents, we also look for DIRTY extents,
since we could have left some extents pinned in the previous transaction that
will never get freed now that we are unmounting, which would cause us to leak
memory. So btrfs_free_super_mirror_extents has been changed to
btrfs_free_pinned_extents, and it will clear the extents locked for the super
mirror, and any remaining pinned extents that may be present. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-27 17:57:01 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
cache = btrfs_lookup_block_group(root->fs_info, bytenr);
|
|
|
|
BUG_ON(!cache);
|
|
|
|
|
|
|
|
pin_down_extent(root, cache, bytenr, num_bytes, reserved);
|
|
|
|
|
|
|
|
btrfs_put_block_group(cache);
|
2009-09-11 20:11:19 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
/*
|
|
|
|
* update size of reserved extents. this function may return -EAGAIN
|
|
|
|
* if 'reserve' is true or 'sinfo' is false.
|
|
|
|
*/
|
|
|
|
static int update_reserved_bytes(struct btrfs_block_group_cache *cache,
|
|
|
|
u64 num_bytes, int reserve, int sinfo)
|
2009-09-11 20:11:19 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
int ret = 0;
|
|
|
|
if (sinfo) {
|
|
|
|
struct btrfs_space_info *space_info = cache->space_info;
|
|
|
|
spin_lock(&space_info->lock);
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (reserve) {
|
|
|
|
if (cache->ro) {
|
|
|
|
ret = -EAGAIN;
|
|
|
|
} else {
|
|
|
|
cache->reserved += num_bytes;
|
|
|
|
space_info->bytes_reserved += num_bytes;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
if (cache->ro)
|
|
|
|
space_info->bytes_readonly += num_bytes;
|
|
|
|
cache->reserved -= num_bytes;
|
|
|
|
space_info->bytes_reserved -= num_bytes;
|
|
|
|
}
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
spin_unlock(&space_info->lock);
|
2009-09-11 20:11:19 +00:00
|
|
|
} else {
|
2010-05-16 14:46:25 +00:00
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (cache->ro) {
|
|
|
|
ret = -EAGAIN;
|
|
|
|
} else {
|
|
|
|
if (reserve)
|
|
|
|
cache->reserved += num_bytes;
|
|
|
|
else
|
|
|
|
cache->reserved -= num_bytes;
|
|
|
|
}
|
|
|
|
spin_unlock(&cache->lock);
|
2007-11-16 19:57:08 +00:00
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
return ret;
|
2007-11-16 19:57:08 +00:00
|
|
|
}
|
2007-04-26 20:46:15 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root)
|
2008-09-26 14:05:48 +00:00
|
|
|
{
|
|
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control *next;
|
|
|
|
struct btrfs_caching_control *caching_ctl;
|
|
|
|
struct btrfs_block_group_cache *cache;
|
2008-09-26 14:05:48 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
down_write(&fs_info->extent_commit_sem);
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
list_for_each_entry_safe(caching_ctl, next,
|
|
|
|
&fs_info->caching_block_groups, list) {
|
|
|
|
cache = caching_ctl->block_group;
|
|
|
|
if (block_group_cache_done(cache)) {
|
|
|
|
cache->last_byte_to_unpin = (u64)-1;
|
|
|
|
list_del_init(&caching_ctl->list);
|
|
|
|
put_caching_control(caching_ctl);
|
2008-09-26 14:05:48 +00:00
|
|
|
} else {
|
2009-09-11 20:11:19 +00:00
|
|
|
cache->last_byte_to_unpin = caching_ctl->progress;
|
2008-09-26 14:05:48 +00:00
|
|
|
}
|
|
|
|
}
|
2009-09-11 20:11:19 +00:00
|
|
|
|
|
|
|
if (fs_info->pinned_extents == &fs_info->freed_extents[0])
|
|
|
|
fs_info->pinned_extents = &fs_info->freed_extents[1];
|
|
|
|
else
|
|
|
|
fs_info->pinned_extents = &fs_info->freed_extents[0];
|
|
|
|
|
|
|
|
up_write(&fs_info->extent_commit_sem);
|
2010-05-16 14:49:58 +00:00
|
|
|
|
|
|
|
update_global_block_rsv(fs_info);
|
2008-09-26 14:05:48 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
|
2007-06-28 19:57:36 +00:00
|
|
|
{
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
|
|
struct btrfs_block_group_cache *cache = NULL;
|
|
|
|
u64 len;
|
2007-06-28 19:57:36 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
while (start <= end) {
|
|
|
|
if (!cache ||
|
|
|
|
start >= cache->key.objectid + cache->key.offset) {
|
|
|
|
if (cache)
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
cache = btrfs_lookup_block_group(fs_info, start);
|
|
|
|
BUG_ON(!cache);
|
|
|
|
}
|
|
|
|
|
|
|
|
len = cache->key.objectid + cache->key.offset - start;
|
|
|
|
len = min(len, end + 1 - start);
|
|
|
|
|
|
|
|
if (start < cache->last_byte_to_unpin) {
|
|
|
|
len = min(len, cache->last_byte_to_unpin - start);
|
|
|
|
btrfs_add_free_space(cache, start, len);
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
start += len;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
spin_lock(&cache->space_info->lock);
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
cache->pinned -= len;
|
|
|
|
cache->space_info->bytes_pinned -= len;
|
2010-05-16 14:46:25 +00:00
|
|
|
if (cache->ro) {
|
|
|
|
cache->space_info->bytes_readonly += len;
|
|
|
|
} else if (cache->reserved_pinned > 0) {
|
|
|
|
len = min(len, cache->reserved_pinned);
|
|
|
|
cache->reserved_pinned -= len;
|
|
|
|
cache->space_info->bytes_reserved += len;
|
|
|
|
}
|
2009-09-11 20:11:19 +00:00
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
spin_unlock(&cache->space_info->lock);
|
2007-06-28 19:57:36 +00:00
|
|
|
}
|
2009-09-11 20:11:19 +00:00
|
|
|
|
|
|
|
if (cache)
|
|
|
|
btrfs_put_block_group(cache);
|
2007-06-28 19:57:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_root *root)
|
2007-03-07 01:08:01 +00:00
|
|
|
{
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
|
|
struct extent_io_tree *unpin;
|
2010-05-16 14:46:25 +00:00
|
|
|
struct btrfs_block_rsv *block_rsv;
|
|
|
|
struct btrfs_block_rsv *next_rsv;
|
2007-10-15 20:15:26 +00:00
|
|
|
u64 start;
|
|
|
|
u64 end;
|
2010-05-16 14:46:25 +00:00
|
|
|
int idx;
|
2007-03-07 01:08:01 +00:00
|
|
|
int ret;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
if (fs_info->pinned_extents == &fs_info->freed_extents[0])
|
|
|
|
unpin = &fs_info->freed_extents[1];
|
|
|
|
else
|
|
|
|
unpin = &fs_info->freed_extents[0];
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (1) {
|
2007-10-15 20:15:26 +00:00
|
|
|
ret = find_first_extent_bit(unpin, 0, &start, &end,
|
|
|
|
EXTENT_DIRTY);
|
|
|
|
if (ret)
|
2007-03-07 01:08:01 +00:00
|
|
|
break;
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
|
|
|
|
ret = btrfs_discard_extent(root, start, end + 1 - start);
|
|
|
|
|
2007-10-15 20:15:26 +00:00
|
|
|
clear_extent_dirty(unpin, start, end, GFP_NOFS);
|
2009-09-11 20:11:19 +00:00
|
|
|
unpin_extent_range(root, start, end);
|
2009-03-13 15:00:37 +00:00
|
|
|
cond_resched();
|
2007-03-07 01:08:01 +00:00
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
mutex_lock(&fs_info->durable_block_rsv_mutex);
|
|
|
|
list_for_each_entry_safe(block_rsv, next_rsv,
|
|
|
|
&fs_info->durable_block_rsv_list, list) {
|
2009-10-14 13:38:28 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
idx = trans->transid & 0x1;
|
|
|
|
if (block_rsv->freed[idx] > 0) {
|
|
|
|
block_rsv_add_bytes(block_rsv,
|
|
|
|
block_rsv->freed[idx], 0);
|
|
|
|
block_rsv->freed[idx] = 0;
|
|
|
|
}
|
|
|
|
if (atomic_read(&block_rsv->usage) == 0) {
|
|
|
|
btrfs_block_rsv_release(root, block_rsv, (u64)-1);
|
2008-09-23 17:14:14 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (block_rsv->freed[0] == 0 &&
|
|
|
|
block_rsv->freed[1] == 0) {
|
|
|
|
list_del_init(&block_rsv->list);
|
|
|
|
kfree(block_rsv);
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
btrfs_block_rsv_release(root, block_rsv, 0);
|
2007-03-26 14:15:30 +00:00
|
|
|
}
|
2007-03-27 15:05:53 +00:00
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
mutex_unlock(&fs_info->durable_block_rsv_mutex);
|
2008-09-23 17:14:14 +00:00
|
|
|
|
2007-03-22 16:13:20 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
|
|
|
u64 root_objectid, u64 owner_objectid,
|
|
|
|
u64 owner_offset, int refs_to_drop,
|
|
|
|
struct btrfs_delayed_extent_op *extent_op)
|
2007-03-07 01:08:01 +00:00
|
|
|
{
|
2007-03-12 20:22:34 +00:00
|
|
|
struct btrfs_key key;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_path *path;
|
2007-03-21 00:35:03 +00:00
|
|
|
struct btrfs_fs_info *info = root->fs_info;
|
|
|
|
struct btrfs_root *extent_root = info->extent_root;
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *leaf;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_extent_item *ei;
|
|
|
|
struct btrfs_extent_inline_ref *iref;
|
2007-03-07 01:08:01 +00:00
|
|
|
int ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int is_data;
|
2008-02-18 21:33:44 +00:00
|
|
|
int extent_slot = 0;
|
|
|
|
int found_extent = 0;
|
|
|
|
int num_to_del = 1;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u32 item_size;
|
|
|
|
u64 refs;
|
2007-03-07 16:50:24 +00:00
|
|
|
|
2007-04-02 15:20:42 +00:00
|
|
|
path = btrfs_alloc_path();
|
2007-06-22 18:16:25 +00:00
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
2007-04-05 14:38:44 +00:00
|
|
|
|
2008-04-21 16:01:38 +00:00
|
|
|
path->reada = 1;
|
2009-03-13 15:00:37 +00:00
|
|
|
path->leave_spinning = 1;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
|
|
|
|
BUG_ON(!is_data && refs_to_drop != 1);
|
|
|
|
|
|
|
|
ret = lookup_extent_backref(trans, extent_root, path, &iref,
|
|
|
|
bytenr, num_bytes, parent,
|
|
|
|
root_objectid, owner_objectid,
|
|
|
|
owner_offset);
|
2007-12-11 14:25:06 +00:00
|
|
|
if (ret == 0) {
|
2008-02-18 21:33:44 +00:00
|
|
|
extent_slot = path->slots[0];
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
while (extent_slot >= 0) {
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key,
|
2008-02-18 21:33:44 +00:00
|
|
|
extent_slot);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (key.objectid != bytenr)
|
2008-02-18 21:33:44 +00:00
|
|
|
break;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (key.type == BTRFS_EXTENT_ITEM_KEY &&
|
|
|
|
key.offset == num_bytes) {
|
2008-02-18 21:33:44 +00:00
|
|
|
found_extent = 1;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (path->slots[0] - extent_slot > 5)
|
|
|
|
break;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
extent_slot--;
|
2008-02-18 21:33:44 +00:00
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
|
|
|
|
if (found_extent && item_size < sizeof(*ei))
|
|
|
|
found_extent = 0;
|
|
|
|
#endif
|
2008-09-23 17:14:14 +00:00
|
|
|
if (!found_extent) {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BUG_ON(iref);
|
2009-03-13 14:10:06 +00:00
|
|
|
ret = remove_extent_backref(trans, extent_root, path,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
NULL, refs_to_drop,
|
|
|
|
is_data);
|
2008-09-23 17:14:14 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
btrfs_release_path(extent_root, path);
|
2009-03-13 15:00:37 +00:00
|
|
|
path->leave_spinning = 1;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
key.objectid = bytenr;
|
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
key.offset = num_bytes;
|
|
|
|
|
2008-09-23 17:14:14 +00:00
|
|
|
ret = btrfs_search_slot(trans, extent_root,
|
|
|
|
&key, path, -1, 1);
|
2008-11-12 19:19:50 +00:00
|
|
|
if (ret) {
|
|
|
|
printk(KERN_ERR "umm, got %d back from search"
|
2009-01-06 02:25:51 +00:00
|
|
|
", was looking for %llu\n", ret,
|
|
|
|
(unsigned long long)bytenr);
|
2008-11-12 19:19:50 +00:00
|
|
|
btrfs_print_leaf(extent_root, path->nodes[0]);
|
|
|
|
}
|
2008-09-23 17:14:14 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
extent_slot = path->slots[0];
|
|
|
|
}
|
2007-12-11 14:25:06 +00:00
|
|
|
} else {
|
|
|
|
btrfs_print_leaf(extent_root, path->nodes[0]);
|
|
|
|
WARN_ON(1);
|
2009-01-06 02:25:51 +00:00
|
|
|
printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
"parent %llu root %llu owner %llu offset %llu\n",
|
2009-01-06 02:25:51 +00:00
|
|
|
(unsigned long long)bytenr,
|
2009-03-13 14:10:06 +00:00
|
|
|
(unsigned long long)parent,
|
2009-01-06 02:25:51 +00:00
|
|
|
(unsigned long long)root_objectid,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
(unsigned long long)owner_objectid,
|
|
|
|
(unsigned long long)owner_offset);
|
2007-12-11 14:25:06 +00:00
|
|
|
}
|
2007-10-15 20:14:19 +00:00
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
item_size = btrfs_item_size_nr(leaf, extent_slot);
|
|
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
|
|
if (item_size < sizeof(*ei)) {
|
|
|
|
BUG_ON(found_extent || extent_slot != path->slots[0]);
|
|
|
|
ret = convert_extent_item_v0(trans, extent_root, path,
|
|
|
|
owner_objectid, 0);
|
|
|
|
BUG_ON(ret < 0);
|
|
|
|
|
|
|
|
btrfs_release_path(extent_root, path);
|
|
|
|
path->leave_spinning = 1;
|
|
|
|
|
|
|
|
key.objectid = bytenr;
|
|
|
|
key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
key.offset = num_bytes;
|
|
|
|
|
|
|
|
ret = btrfs_search_slot(trans, extent_root, &key, path,
|
|
|
|
-1, 1);
|
|
|
|
if (ret) {
|
|
|
|
printk(KERN_ERR "umm, got %d back from search"
|
|
|
|
", was looking for %llu\n", ret,
|
|
|
|
(unsigned long long)bytenr);
|
|
|
|
btrfs_print_leaf(extent_root, path->nodes[0]);
|
|
|
|
}
|
|
|
|
BUG_ON(ret);
|
|
|
|
extent_slot = path->slots[0];
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
item_size = btrfs_item_size_nr(leaf, extent_slot);
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
BUG_ON(item_size < sizeof(*ei));
|
2008-02-18 21:33:44 +00:00
|
|
|
ei = btrfs_item_ptr(leaf, extent_slot,
|
2007-03-14 18:14:43 +00:00
|
|
|
struct btrfs_extent_item);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
struct btrfs_tree_block_info *bi;
|
|
|
|
BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
|
|
|
|
bi = (struct btrfs_tree_block_info *)(ei + 1);
|
|
|
|
WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
|
|
|
|
}
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
refs = btrfs_extent_refs(leaf, ei);
|
2009-03-13 14:10:06 +00:00
|
|
|
BUG_ON(refs < refs_to_drop);
|
|
|
|
refs -= refs_to_drop;
|
2007-10-15 20:14:19 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (refs > 0) {
|
|
|
|
if (extent_op)
|
|
|
|
__run_delayed_extent_op(extent_op, leaf, ei);
|
|
|
|
/*
|
|
|
|
* In the case of inline back ref, reference count will
|
|
|
|
* be updated by remove_extent_backref
|
2008-02-18 21:33:44 +00:00
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (iref) {
|
|
|
|
BUG_ON(!found_extent);
|
|
|
|
} else {
|
|
|
|
btrfs_set_extent_refs(leaf, ei, refs);
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
}
|
|
|
|
if (found_extent) {
|
|
|
|
ret = remove_extent_backref(trans, extent_root, path,
|
|
|
|
iref, refs_to_drop,
|
|
|
|
is_data);
|
2008-02-18 21:33:44 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} else {
|
|
|
|
if (found_extent) {
|
|
|
|
BUG_ON(is_data && refs_to_drop !=
|
|
|
|
extent_data_ref_count(root, path, iref));
|
|
|
|
if (iref) {
|
|
|
|
BUG_ON(path->slots[0] != extent_slot);
|
|
|
|
} else {
|
|
|
|
BUG_ON(path->slots[0] != extent_slot + 1);
|
|
|
|
path->slots[0] = extent_slot;
|
|
|
|
num_to_del = 2;
|
|
|
|
}
|
2007-03-25 15:35:08 +00:00
|
|
|
}
|
2009-03-13 15:00:37 +00:00
|
|
|
|
2008-02-18 21:33:44 +00:00
|
|
|
ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
|
|
|
|
num_to_del);
|
2008-09-23 17:14:14 +00:00
|
|
|
BUG_ON(ret);
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
btrfs_release_path(extent_root, path);
|
2008-08-12 13:13:26 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (is_data) {
|
2008-12-10 14:10:46 +00:00
|
|
|
ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
|
|
|
|
BUG_ON(ret);
|
2009-03-31 17:47:50 +00:00
|
|
|
} else {
|
|
|
|
invalidate_mapping_pages(info->btree_inode->i_mapping,
|
|
|
|
bytenr >> PAGE_CACHE_SHIFT,
|
|
|
|
(bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
|
2008-12-10 14:10:46 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = update_block_group(trans, root, bytenr, num_bytes, 0);
|
2008-12-16 18:51:01 +00:00
|
|
|
BUG_ON(ret);
|
2007-03-07 01:08:01 +00:00
|
|
|
}
|
2007-04-02 15:20:42 +00:00
|
|
|
btrfs_free_path(path);
|
2007-03-07 01:08:01 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2009-03-13 14:11:24 +00:00
|
|
|
/*
|
2010-05-16 14:46:25 +00:00
|
|
|
* when we free an block, it is possible (and likely) that we free the last
|
2009-03-13 14:11:24 +00:00
|
|
|
* delayed ref for that extent as well. This searches the delayed ref tree for
|
|
|
|
* a given extent, and if there are no other delayed refs to be processed, it
|
|
|
|
* removes it from the tree.
|
|
|
|
*/
|
|
|
|
static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 bytenr)
|
|
|
|
{
|
|
|
|
struct btrfs_delayed_ref_head *head;
|
|
|
|
struct btrfs_delayed_ref_root *delayed_refs;
|
|
|
|
struct btrfs_delayed_ref_node *ref;
|
|
|
|
struct rb_node *node;
|
2010-05-16 14:46:25 +00:00
|
|
|
int ret = 0;
|
2009-03-13 14:11:24 +00:00
|
|
|
|
|
|
|
delayed_refs = &trans->transaction->delayed_refs;
|
|
|
|
spin_lock(&delayed_refs->lock);
|
|
|
|
head = btrfs_find_delayed_ref_head(trans, bytenr);
|
|
|
|
if (!head)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
node = rb_prev(&head->node.rb_node);
|
|
|
|
if (!node)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
|
|
|
|
|
|
|
|
/* there are still entries for this ref, we can't drop it */
|
|
|
|
if (ref->bytenr == bytenr)
|
|
|
|
goto out;
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (head->extent_op) {
|
|
|
|
if (!head->must_insert_reserved)
|
|
|
|
goto out;
|
|
|
|
kfree(head->extent_op);
|
|
|
|
head->extent_op = NULL;
|
|
|
|
}
|
|
|
|
|
2009-03-13 14:11:24 +00:00
|
|
|
/*
|
|
|
|
* waiting for the lock here would deadlock. If someone else has it
|
|
|
|
* locked they are already in the process of dropping it anyway
|
|
|
|
*/
|
|
|
|
if (!mutex_trylock(&head->mutex))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* at this point we have a head with no other entries. Go
|
|
|
|
* ahead and process it.
|
|
|
|
*/
|
|
|
|
head->node.in_tree = 0;
|
|
|
|
rb_erase(&head->node.rb_node, &delayed_refs->root);
|
2009-03-13 14:17:05 +00:00
|
|
|
|
2009-03-13 14:11:24 +00:00
|
|
|
delayed_refs->num_entries--;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* we don't take a ref on the node because we're removing it from the
|
|
|
|
* tree, so we just steal the ref the tree was holding.
|
|
|
|
*/
|
2009-03-13 14:17:05 +00:00
|
|
|
delayed_refs->num_heads--;
|
|
|
|
if (list_empty(&head->cluster))
|
|
|
|
delayed_refs->num_heads_ready--;
|
|
|
|
|
|
|
|
list_del_init(&head->cluster);
|
2009-03-13 14:11:24 +00:00
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
BUG_ON(head->extent_op);
|
|
|
|
if (head->must_insert_reserved)
|
|
|
|
ret = 1;
|
|
|
|
|
|
|
|
mutex_unlock(&head->mutex);
|
2009-03-13 14:11:24 +00:00
|
|
|
btrfs_put_delayed_ref(&head->node);
|
2010-05-16 14:46:25 +00:00
|
|
|
return ret;
|
2009-03-13 14:11:24 +00:00
|
|
|
out:
|
|
|
|
spin_unlock(&delayed_refs->lock);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf,
|
|
|
|
u64 parent, int last_ref)
|
|
|
|
{
|
|
|
|
struct btrfs_block_rsv *block_rsv;
|
|
|
|
struct btrfs_block_group_cache *cache = NULL;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
|
|
|
|
ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
|
|
|
|
parent, root->root_key.objectid,
|
|
|
|
btrfs_header_level(buf),
|
|
|
|
BTRFS_DROP_DELAYED_REF, NULL);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!last_ref)
|
|
|
|
return;
|
|
|
|
|
|
|
|
block_rsv = get_block_rsv(trans, root);
|
|
|
|
cache = btrfs_lookup_block_group(root->fs_info, buf->start);
|
2010-05-31 09:04:46 +00:00
|
|
|
if (block_rsv->space_info != cache->space_info)
|
|
|
|
goto out;
|
2010-05-16 14:46:25 +00:00
|
|
|
|
|
|
|
if (btrfs_header_generation(buf) == trans->transid) {
|
|
|
|
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
|
|
|
|
ret = check_ref_cleanup(trans, root, buf->start);
|
|
|
|
if (!ret)
|
|
|
|
goto pin;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
|
|
|
|
pin_down_extent(root, cache, buf->start, buf->len, 1);
|
|
|
|
goto pin;
|
|
|
|
}
|
|
|
|
|
|
|
|
WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
|
|
|
|
|
|
|
|
btrfs_add_free_space(cache, buf->start, buf->len);
|
|
|
|
ret = update_reserved_bytes(cache, buf->len, 0, 0);
|
|
|
|
if (ret == -EAGAIN) {
|
|
|
|
/* block group became read-only */
|
|
|
|
update_reserved_bytes(cache, buf->len, 0, 1);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = 1;
|
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
if (block_rsv->reserved < block_rsv->size) {
|
|
|
|
block_rsv->reserved += buf->len;
|
|
|
|
ret = 0;
|
|
|
|
}
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
|
|
|
|
if (ret) {
|
|
|
|
spin_lock(&cache->space_info->lock);
|
|
|
|
cache->space_info->bytes_reserved -= buf->len;
|
|
|
|
spin_unlock(&cache->space_info->lock);
|
|
|
|
}
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
pin:
|
|
|
|
if (block_rsv->durable && !cache->ro) {
|
|
|
|
ret = 0;
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
if (!cache->ro) {
|
|
|
|
cache->reserved_pinned += buf->len;
|
|
|
|
ret = 1;
|
|
|
|
}
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
|
|
|
|
if (ret) {
|
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
block_rsv->freed[trans->transid & 0x1] += buf->len;
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
out:
|
|
|
|
btrfs_put_block_group(cache);
|
|
|
|
}
|
|
|
|
|
2008-06-25 20:01:30 +00:00
|
|
|
int btrfs_free_extent(struct btrfs_trans_handle *trans,
|
2008-09-23 17:14:14 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u64 root_objectid, u64 owner, u64 offset)
|
2008-06-25 20:01:30 +00:00
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
2009-03-13 14:10:06 +00:00
|
|
|
/*
|
|
|
|
* tree log blocks never actually go into the extent allocation
|
|
|
|
* tree, just update pinning info and exit early.
|
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
|
|
|
|
WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
|
2009-03-13 15:00:37 +00:00
|
|
|
/* unlocks the pinned mutex */
|
2009-09-11 20:11:19 +00:00
|
|
|
btrfs_pin_extent(root, bytenr, num_bytes, 1);
|
2009-03-13 14:10:06 +00:00
|
|
|
ret = 0;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
|
|
|
|
parent, root_objectid, (int)owner,
|
|
|
|
BTRFS_DROP_DELAYED_REF, NULL);
|
2009-03-13 14:11:24 +00:00
|
|
|
BUG_ON(ret);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} else {
|
|
|
|
ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
|
|
|
|
parent, root_objectid, owner,
|
|
|
|
offset, BTRFS_DROP_DELAYED_REF, NULL);
|
|
|
|
BUG_ON(ret);
|
2009-03-13 14:10:06 +00:00
|
|
|
}
|
2008-06-25 20:01:30 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2007-11-30 16:30:34 +00:00
|
|
|
static u64 stripe_align(struct btrfs_root *root, u64 val)
|
|
|
|
{
|
|
|
|
u64 mask = ((u64)root->stripesize - 1);
|
|
|
|
u64 ret = (val + mask) & ~mask;
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
/*
|
|
|
|
* when we wait for progress in the block group caching, its because
|
|
|
|
* our allocation attempt failed at least once. So, we must sleep
|
|
|
|
* and let some progress happen before we try again.
|
|
|
|
*
|
|
|
|
* This function will sleep at least once waiting for new free space to
|
|
|
|
* show up, and then it will check the block group free space numbers
|
|
|
|
* for our min num_bytes. Another option is to have it go ahead
|
|
|
|
* and look in the rbtree for a free extent of a given size, but this
|
|
|
|
* is a good start.
|
|
|
|
*/
|
|
|
|
static noinline int
|
|
|
|
wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
|
|
|
|
u64 num_bytes)
|
|
|
|
{
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control *caching_ctl;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
DEFINE_WAIT(wait);
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
caching_ctl = get_caching_control(cache);
|
|
|
|
if (!caching_ctl)
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
return 0;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
(cache->free_space >= num_bytes));
|
2009-09-11 20:11:19 +00:00
|
|
|
|
|
|
|
put_caching_control(caching_ctl);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static noinline int
|
|
|
|
wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
struct btrfs_caching_control *caching_ctl;
|
|
|
|
DEFINE_WAIT(wait);
|
|
|
|
|
|
|
|
caching_ctl = get_caching_control(cache);
|
|
|
|
if (!caching_ctl)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
wait_event(caching_ctl->wait, block_group_cache_done(cache));
|
|
|
|
|
|
|
|
put_caching_control(caching_ctl);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
static int get_block_group_index(struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
int index;
|
|
|
|
if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
|
|
|
|
index = 0;
|
|
|
|
else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
|
|
|
|
index = 1;
|
|
|
|
else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
|
|
|
|
index = 2;
|
|
|
|
else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
|
|
|
|
index = 3;
|
|
|
|
else
|
|
|
|
index = 4;
|
|
|
|
return index;
|
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
enum btrfs_loop_type {
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
LOOP_FIND_IDEAL = 0,
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
LOOP_CACHING_NOWAIT = 1,
|
|
|
|
LOOP_CACHING_WAIT = 2,
|
|
|
|
LOOP_ALLOC_CHUNK = 3,
|
|
|
|
LOOP_NO_EMPTY_SIZE = 4,
|
|
|
|
};
|
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
|
|
|
* walks the btree of allocated extents and find a hole of a given size.
|
|
|
|
* The key ins is changed to record the hole:
|
|
|
|
* ins->objectid == block start
|
2007-03-15 16:56:47 +00:00
|
|
|
* ins->flags = BTRFS_EXTENT_ITEM_KEY
|
2007-02-26 15:40:21 +00:00
|
|
|
* ins->offset == number of blocks
|
|
|
|
* Any available blocks before search_start are skipped.
|
|
|
|
*/
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int find_free_extent(struct btrfs_trans_handle *trans,
|
2008-01-03 15:01:48 +00:00
|
|
|
struct btrfs_root *orig_root,
|
|
|
|
u64 num_bytes, u64 empty_size,
|
|
|
|
u64 search_start, u64 search_end,
|
|
|
|
u64 hint_byte, struct btrfs_key *ins,
|
|
|
|
int data)
|
2007-02-26 15:40:21 +00:00
|
|
|
{
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
int ret = 0;
|
2009-01-06 02:25:51 +00:00
|
|
|
struct btrfs_root *root = orig_root->fs_info->extent_root;
|
2009-04-03 13:47:43 +00:00
|
|
|
struct btrfs_free_cluster *last_ptr = NULL;
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
struct btrfs_block_group_cache *block_group = NULL;
|
2008-03-24 19:02:07 +00:00
|
|
|
int empty_cluster = 2 * 1024 * 1024;
|
2008-05-24 18:04:53 +00:00
|
|
|
int allowed_chunk_alloc = 0;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
int done_chunk_alloc = 0;
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
2009-04-03 13:47:43 +00:00
|
|
|
int last_ptr_loop = 0;
|
|
|
|
int loop = 0;
|
2010-05-16 14:46:25 +00:00
|
|
|
int index = 0;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
bool found_uncached_bg = false;
|
2009-09-11 20:11:20 +00:00
|
|
|
bool failed_cluster_refill = false;
|
2009-10-06 14:04:28 +00:00
|
|
|
bool failed_alloc = false;
|
2010-09-16 20:19:09 +00:00
|
|
|
bool use_cluster = true;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
u64 ideal_cache_percent = 0;
|
|
|
|
u64 ideal_cache_offset = 0;
|
2007-02-26 15:40:21 +00:00
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
WARN_ON(num_bytes < root->sectorsize);
|
2007-04-04 19:27:52 +00:00
|
|
|
btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
ins->objectid = 0;
|
|
|
|
ins->offset = 0;
|
2007-04-04 19:27:52 +00:00
|
|
|
|
2009-04-03 14:14:19 +00:00
|
|
|
space_info = __find_space_info(root->fs_info, data);
|
2010-03-19 20:49:55 +00:00
|
|
|
if (!space_info) {
|
|
|
|
printk(KERN_ERR "No space info for %d\n", data);
|
|
|
|
return -ENOSPC;
|
|
|
|
}
|
2009-04-03 14:14:19 +00:00
|
|
|
|
2010-09-16 20:19:09 +00:00
|
|
|
/*
|
|
|
|
* If the space info is for both data and metadata it means we have a
|
|
|
|
* small filesystem and we can't use the clustering stuff.
|
|
|
|
*/
|
|
|
|
if (btrfs_mixed_space_info(space_info))
|
|
|
|
use_cluster = false;
|
|
|
|
|
2008-05-24 18:04:53 +00:00
|
|
|
if (orig_root->ref_cows || empty_size)
|
|
|
|
allowed_chunk_alloc = 1;
|
|
|
|
|
2010-09-16 20:19:09 +00:00
|
|
|
if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
|
2009-04-03 13:47:43 +00:00
|
|
|
last_ptr = &root->fs_info->meta_alloc_cluster;
|
2009-02-12 14:41:38 +00:00
|
|
|
if (!btrfs_test_opt(root, SSD))
|
|
|
|
empty_cluster = 64 * 1024;
|
2008-03-24 19:02:07 +00:00
|
|
|
}
|
|
|
|
|
2010-09-16 20:19:09 +00:00
|
|
|
if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
|
|
|
|
btrfs_test_opt(root, SSD)) {
|
2009-04-03 13:47:43 +00:00
|
|
|
last_ptr = &root->fs_info->data_alloc_cluster;
|
|
|
|
}
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2008-03-24 19:02:07 +00:00
|
|
|
if (last_ptr) {
|
2009-04-03 13:47:43 +00:00
|
|
|
spin_lock(&last_ptr->lock);
|
|
|
|
if (last_ptr->block_group)
|
|
|
|
hint_byte = last_ptr->window_start;
|
|
|
|
spin_unlock(&last_ptr->lock);
|
2008-03-24 19:02:07 +00:00
|
|
|
}
|
2009-04-03 13:47:43 +00:00
|
|
|
|
2008-05-07 15:43:44 +00:00
|
|
|
search_start = max(search_start, first_logical_byte(root, 0));
|
2008-03-24 19:02:07 +00:00
|
|
|
search_start = max(search_start, hint_byte);
|
2008-03-24 19:01:56 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (!last_ptr)
|
2009-04-03 13:47:43 +00:00
|
|
|
empty_cluster = 0;
|
|
|
|
|
2009-04-03 14:14:19 +00:00
|
|
|
if (search_start == hint_byte) {
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
ideal_cache:
|
2009-04-03 14:14:19 +00:00
|
|
|
block_group = btrfs_lookup_block_group(root->fs_info,
|
|
|
|
search_start);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
/*
|
|
|
|
* we don't want to use the block group if it doesn't match our
|
|
|
|
* allocation bits, or if its not cached.
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
*
|
|
|
|
* However if we are re-searching with an ideal block group
|
|
|
|
* picked out then we don't care that the block group is cached.
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
*/
|
|
|
|
if (block_group && block_group_bits(block_group, data) &&
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
(block_group->cached != BTRFS_CACHE_NO ||
|
|
|
|
search_start == ideal_cache_offset)) {
|
2009-04-03 14:14:19 +00:00
|
|
|
down_read(&space_info->groups_sem);
|
2009-06-04 19:34:51 +00:00
|
|
|
if (list_empty(&block_group->list) ||
|
|
|
|
block_group->ro) {
|
|
|
|
/*
|
|
|
|
* someone is removing this block group,
|
|
|
|
* we can't jump into the have_block_group
|
|
|
|
* target because our list pointers are not
|
|
|
|
* valid
|
|
|
|
*/
|
|
|
|
btrfs_put_block_group(block_group);
|
|
|
|
up_read(&space_info->groups_sem);
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
} else {
|
2010-05-16 14:46:24 +00:00
|
|
|
index = get_block_group_index(block_group);
|
2009-06-04 19:34:51 +00:00
|
|
|
goto have_block_group;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
}
|
2009-04-03 14:14:19 +00:00
|
|
|
} else if (block_group) {
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
2009-04-03 14:14:19 +00:00
|
|
|
}
|
2008-11-07 23:17:11 +00:00
|
|
|
}
|
2009-04-03 14:14:19 +00:00
|
|
|
search:
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
down_read(&space_info->groups_sem);
|
2010-05-16 14:46:24 +00:00
|
|
|
list_for_each_entry(block_group, &space_info->block_groups[index],
|
|
|
|
list) {
|
2009-04-03 14:14:18 +00:00
|
|
|
u64 offset;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
int cached;
|
2008-11-10 21:13:54 +00:00
|
|
|
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_get_block_group(block_group);
|
2009-04-03 14:14:19 +00:00
|
|
|
search_start = block_group->key.objectid;
|
2008-11-07 23:17:11 +00:00
|
|
|
|
2010-12-13 20:06:46 +00:00
|
|
|
/*
|
|
|
|
* this can happen if we end up cycling through all the
|
|
|
|
* raid types, but we want to make sure we only allocate
|
|
|
|
* for the proper type.
|
|
|
|
*/
|
|
|
|
if (!block_group_bits(block_group, data)) {
|
|
|
|
u64 extra = BTRFS_BLOCK_GROUP_DUP |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID10;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* if they asked for extra copies and this block group
|
|
|
|
* doesn't provide them, bail. This does allow us to
|
|
|
|
* fill raid0 from raid1.
|
|
|
|
*/
|
|
|
|
if ((data & extra) && !(block_group->flags & extra))
|
|
|
|
goto loop;
|
|
|
|
}
|
|
|
|
|
2009-04-03 14:14:19 +00:00
|
|
|
have_block_group:
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
u64 free_percent;
|
|
|
|
|
2010-12-08 14:15:11 +00:00
|
|
|
ret = cache_block_group(block_group, trans,
|
|
|
|
orig_root, 1);
|
2010-08-25 20:54:15 +00:00
|
|
|
if (block_group->cached == BTRFS_CACHE_FINISHED)
|
|
|
|
goto have_block_group;
|
|
|
|
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
free_percent = btrfs_block_group_used(&block_group->item);
|
|
|
|
free_percent *= 100;
|
|
|
|
free_percent = div64_u64(free_percent,
|
|
|
|
block_group->key.offset);
|
|
|
|
free_percent = 100 - free_percent;
|
|
|
|
if (free_percent > ideal_cache_percent &&
|
|
|
|
likely(!block_group->ro)) {
|
|
|
|
ideal_cache_offset = block_group->key.objectid;
|
|
|
|
ideal_cache_percent = free_percent;
|
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
/*
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
* We only want to start kthread caching if we are at
|
|
|
|
* the point where we will wait for caching to make
|
|
|
|
* progress, or if our ideal search is over and we've
|
|
|
|
* found somebody to start caching.
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
*/
|
|
|
|
if (loop > LOOP_CACHING_NOWAIT ||
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
(loop > LOOP_FIND_IDEAL &&
|
|
|
|
atomic_read(&space_info->caching_threads) < 2)) {
|
2010-12-08 14:15:11 +00:00
|
|
|
ret = cache_block_group(block_group, trans,
|
|
|
|
orig_root, 0);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
BUG_ON(ret);
|
2009-04-03 14:14:19 +00:00
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
found_uncached_bg = true;
|
|
|
|
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
/*
|
|
|
|
* If loop is set for cached only, try the next block
|
|
|
|
* group.
|
|
|
|
*/
|
|
|
|
if (loop == LOOP_FIND_IDEAL)
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
goto loop;
|
|
|
|
}
|
|
|
|
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
cached = block_group_cache_done(block_group);
|
|
|
|
if (unlikely(!cached))
|
|
|
|
found_uncached_bg = true;
|
|
|
|
|
2008-11-20 17:16:16 +00:00
|
|
|
if (unlikely(block_group->ro))
|
2009-04-03 14:14:19 +00:00
|
|
|
goto loop;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2009-09-11 20:11:20 +00:00
|
|
|
/*
|
|
|
|
* Ok we want to try and use the cluster allocator, so lets look
|
|
|
|
* there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
|
|
|
|
* have tried the cluster allocator plenty of times at this
|
|
|
|
* point and not have found anything, so we are likely way too
|
|
|
|
* fragmented for the clustering stuff to find anything, so lets
|
|
|
|
* just skip it and let the allocator find whatever block it can
|
|
|
|
* find
|
|
|
|
*/
|
|
|
|
if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
|
2009-04-03 13:47:43 +00:00
|
|
|
/*
|
|
|
|
* the refill lock keeps out other
|
|
|
|
* people trying to start a new cluster
|
|
|
|
*/
|
|
|
|
spin_lock(&last_ptr->refill_lock);
|
2009-06-04 19:34:51 +00:00
|
|
|
if (last_ptr->block_group &&
|
|
|
|
(last_ptr->block_group->ro ||
|
|
|
|
!block_group_bits(last_ptr->block_group, data))) {
|
|
|
|
offset = 0;
|
|
|
|
goto refill_cluster;
|
|
|
|
}
|
|
|
|
|
2009-04-03 13:47:43 +00:00
|
|
|
offset = btrfs_alloc_from_cluster(block_group, last_ptr,
|
|
|
|
num_bytes, search_start);
|
|
|
|
if (offset) {
|
|
|
|
/* we have a block, we're done */
|
|
|
|
spin_unlock(&last_ptr->refill_lock);
|
|
|
|
goto checks;
|
|
|
|
}
|
|
|
|
|
|
|
|
spin_lock(&last_ptr->lock);
|
|
|
|
/*
|
|
|
|
* whoops, this cluster doesn't actually point to
|
|
|
|
* this block group. Get a ref on the block
|
|
|
|
* group is does point to and try again
|
|
|
|
*/
|
|
|
|
if (!last_ptr_loop && last_ptr->block_group &&
|
|
|
|
last_ptr->block_group != block_group) {
|
|
|
|
|
|
|
|
btrfs_put_block_group(block_group);
|
|
|
|
block_group = last_ptr->block_group;
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_get_block_group(block_group);
|
2009-04-03 13:47:43 +00:00
|
|
|
spin_unlock(&last_ptr->lock);
|
|
|
|
spin_unlock(&last_ptr->refill_lock);
|
|
|
|
|
|
|
|
last_ptr_loop = 1;
|
|
|
|
search_start = block_group->key.objectid;
|
2009-06-04 19:34:51 +00:00
|
|
|
/*
|
|
|
|
* we know this block group is properly
|
|
|
|
* in the list because
|
|
|
|
* btrfs_remove_block_group, drops the
|
|
|
|
* cluster before it removes the block
|
|
|
|
* group from the list
|
|
|
|
*/
|
2009-04-03 13:47:43 +00:00
|
|
|
goto have_block_group;
|
|
|
|
}
|
|
|
|
spin_unlock(&last_ptr->lock);
|
2009-06-04 19:34:51 +00:00
|
|
|
refill_cluster:
|
2009-04-03 13:47:43 +00:00
|
|
|
/*
|
|
|
|
* this cluster didn't work out, free it and
|
|
|
|
* start over
|
|
|
|
*/
|
|
|
|
btrfs_return_cluster_to_free_space(NULL, last_ptr);
|
|
|
|
|
|
|
|
last_ptr_loop = 0;
|
|
|
|
|
|
|
|
/* allocate a cluster in this block group */
|
2009-06-10 00:28:34 +00:00
|
|
|
ret = btrfs_find_space_cluster(trans, root,
|
2009-04-03 13:47:43 +00:00
|
|
|
block_group, last_ptr,
|
|
|
|
offset, num_bytes,
|
|
|
|
empty_cluster + empty_size);
|
|
|
|
if (ret == 0) {
|
|
|
|
/*
|
|
|
|
* now pull our allocation out of this
|
|
|
|
* cluster
|
|
|
|
*/
|
|
|
|
offset = btrfs_alloc_from_cluster(block_group,
|
|
|
|
last_ptr, num_bytes,
|
|
|
|
search_start);
|
|
|
|
if (offset) {
|
|
|
|
/* we found one, proceed */
|
|
|
|
spin_unlock(&last_ptr->refill_lock);
|
|
|
|
goto checks;
|
|
|
|
}
|
2009-09-11 20:11:20 +00:00
|
|
|
} else if (!cached && loop > LOOP_CACHING_NOWAIT
|
|
|
|
&& !failed_cluster_refill) {
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
spin_unlock(&last_ptr->refill_lock);
|
|
|
|
|
2009-09-11 20:11:20 +00:00
|
|
|
failed_cluster_refill = true;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
wait_block_group_cache_progress(block_group,
|
|
|
|
num_bytes + empty_cluster + empty_size);
|
|
|
|
goto have_block_group;
|
2009-04-03 13:47:43 +00:00
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2009-04-03 13:47:43 +00:00
|
|
|
/*
|
|
|
|
* at this point we either didn't find a cluster
|
|
|
|
* or we weren't able to allocate a block from our
|
|
|
|
* cluster. Free the cluster we've been trying
|
|
|
|
* to use, and go to the next block group
|
|
|
|
*/
|
2009-09-11 20:11:20 +00:00
|
|
|
btrfs_return_cluster_to_free_space(NULL, last_ptr);
|
2009-04-03 13:47:43 +00:00
|
|
|
spin_unlock(&last_ptr->refill_lock);
|
2009-09-11 20:11:20 +00:00
|
|
|
goto loop;
|
2009-04-03 13:47:43 +00:00
|
|
|
}
|
|
|
|
|
2009-04-03 14:14:18 +00:00
|
|
|
offset = btrfs_find_space_for_alloc(block_group, search_start,
|
|
|
|
num_bytes, empty_size);
|
2009-10-06 14:04:28 +00:00
|
|
|
/*
|
|
|
|
* If we didn't find a chunk, and we haven't failed on this
|
|
|
|
* block group before, and this block group is in the middle of
|
|
|
|
* caching and we are ok with waiting, then go ahead and wait
|
|
|
|
* for progress to be made, and set failed_alloc to true.
|
|
|
|
*
|
|
|
|
* If failed_alloc is true then we've already waited on this
|
|
|
|
* block group once and should move on to the next block group.
|
|
|
|
*/
|
|
|
|
if (!offset && !failed_alloc && !cached &&
|
|
|
|
loop > LOOP_CACHING_NOWAIT) {
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
wait_block_group_cache_progress(block_group,
|
2009-10-06 14:04:28 +00:00
|
|
|
num_bytes + empty_size);
|
|
|
|
failed_alloc = true;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
goto have_block_group;
|
2009-10-06 14:04:28 +00:00
|
|
|
} else if (!offset) {
|
|
|
|
goto loop;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
2009-04-03 13:47:43 +00:00
|
|
|
checks:
|
2009-04-03 14:14:18 +00:00
|
|
|
search_start = stripe_align(root, offset);
|
2009-04-03 14:14:19 +00:00
|
|
|
/* move on to the next group */
|
2009-04-03 14:14:18 +00:00
|
|
|
if (search_start + num_bytes >= search_end) {
|
|
|
|
btrfs_add_free_space(block_group, offset, num_bytes);
|
2009-04-03 14:14:19 +00:00
|
|
|
goto loop;
|
2009-04-03 14:14:18 +00:00
|
|
|
}
|
Btrfs: nuke fs wide allocation mutex V2
This patch removes the giant fs_info->alloc_mutex and replaces it with a bunch
of little locks.
There is now a pinned_mutex, which is used when messing with the pinned_extents
extent io tree, and the extent_ins_mutex which is used with the pending_del and
extent_ins extent io trees.
The locking for the extent tree stuff was inspired by a patch that Yan Zheng
wrote to fix a race condition, I cleaned it up some and changed the locking
around a little bit, but the idea remains the same. Basically instead of
holding the extent_ins_mutex throughout the processing of an extent on the
extent_ins or pending_del trees, we just hold it while we're searching and when
we clear the bits on those trees, and lock the extent for the duration of the
operations on the extent.
Also to keep from getting hung up waiting to lock an extent, I've added a
try_lock_extent so if we cannot lock the extent, move on to the next one in the
tree and we'll come back to that one. I have tested this heavily and it does
not appear to break anything. This has to be applied on top of my
find_free_extent redo patch.
I tested this patch on top of Yan's space reblancing code and it worked fine.
The only thing that has changed since the last version is I pulled out all my
debugging stuff, apparently I forgot to run guilt refresh before I sent the
last patch out. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-04-03 14:14:19 +00:00
|
|
|
/* move on to the next group */
|
|
|
|
if (search_start + num_bytes >
|
2009-04-03 14:14:18 +00:00
|
|
|
block_group->key.objectid + block_group->key.offset) {
|
|
|
|
btrfs_add_free_space(block_group, offset, num_bytes);
|
2009-04-03 14:14:19 +00:00
|
|
|
goto loop;
|
2009-04-03 14:14:18 +00:00
|
|
|
}
|
2008-11-10 16:47:09 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ins->objectid = search_start;
|
|
|
|
ins->offset = num_bytes;
|
2009-04-03 14:14:19 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (offset < search_start)
|
|
|
|
btrfs_add_free_space(block_group, offset,
|
|
|
|
search_start - offset);
|
|
|
|
BUG_ON(offset > search_start);
|
2009-04-03 14:14:19 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = update_reserved_bytes(block_group, num_bytes, 1,
|
|
|
|
(data & BTRFS_BLOCK_GROUP_DATA));
|
|
|
|
if (ret == -EAGAIN) {
|
2009-04-03 14:14:18 +00:00
|
|
|
btrfs_add_free_space(block_group, offset, num_bytes);
|
2009-04-03 14:14:19 +00:00
|
|
|
goto loop;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
}
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
/* we are all good, lets return */
|
2009-04-03 14:14:19 +00:00
|
|
|
ins->objectid = search_start;
|
|
|
|
ins->offset = num_bytes;
|
2008-12-11 21:30:39 +00:00
|
|
|
|
2009-04-03 14:14:18 +00:00
|
|
|
if (offset < search_start)
|
|
|
|
btrfs_add_free_space(block_group, offset,
|
|
|
|
search_start - offset);
|
|
|
|
BUG_ON(offset > search_start);
|
2009-04-03 14:14:19 +00:00
|
|
|
break;
|
|
|
|
loop:
|
2009-09-11 20:11:20 +00:00
|
|
|
failed_cluster_refill = false;
|
2009-10-06 14:04:28 +00:00
|
|
|
failed_alloc = false;
|
2010-05-16 14:46:24 +00:00
|
|
|
BUG_ON(index != get_block_group_index(block_group));
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
2009-04-03 14:14:19 +00:00
|
|
|
}
|
|
|
|
up_read(&space_info->groups_sem);
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
|
|
|
|
goto search;
|
|
|
|
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
/* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
|
|
|
|
* for them to make caching progress. Also
|
|
|
|
* determine the best possible bg to cache
|
|
|
|
* LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
|
|
|
|
* caching kthreads as we move along
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
* LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
|
|
|
|
* LOOP_ALLOC_CHUNK, force a chunk allocation and try again
|
|
|
|
* LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
|
|
|
|
* again
|
2009-04-03 13:47:43 +00:00
|
|
|
*/
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE &&
|
|
|
|
(found_uncached_bg || empty_size || empty_cluster ||
|
|
|
|
allowed_chunk_alloc)) {
|
2010-05-16 14:46:24 +00:00
|
|
|
index = 0;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
found_uncached_bg = false;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
loop++;
|
|
|
|
if (!ideal_cache_percent &&
|
|
|
|
atomic_read(&space_info->caching_threads))
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
goto search;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* 1 of the following 2 things have happened so far
|
|
|
|
*
|
|
|
|
* 1) We found an ideal block group for caching that
|
|
|
|
* is mostly full and will cache quickly, so we might
|
|
|
|
* as well wait for it.
|
|
|
|
*
|
|
|
|
* 2) We searched for cached only and we didn't find
|
|
|
|
* anything, and we didn't start any caching kthreads
|
|
|
|
* either, so chances are we will loop through and
|
|
|
|
* start a couple caching kthreads, and then come back
|
|
|
|
* around and just wait for them. This will be slower
|
|
|
|
* because we will have 2 caching kthreads reading at
|
|
|
|
* the same time when we could have just started one
|
|
|
|
* and waited for it to get far enough to give us an
|
|
|
|
* allocation, so go ahead and go to the wait caching
|
|
|
|
* loop.
|
|
|
|
*/
|
|
|
|
loop = LOOP_CACHING_WAIT;
|
|
|
|
search_start = ideal_cache_offset;
|
|
|
|
ideal_cache_percent = 0;
|
|
|
|
goto ideal_cache;
|
|
|
|
} else if (loop == LOOP_FIND_IDEAL) {
|
|
|
|
/*
|
|
|
|
* Didn't find a uncached bg, wait on anything we find
|
|
|
|
* next.
|
|
|
|
*/
|
|
|
|
loop = LOOP_CACHING_WAIT;
|
|
|
|
goto search;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (loop < LOOP_CACHING_WAIT) {
|
|
|
|
loop++;
|
|
|
|
goto search;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (loop == LOOP_ALLOC_CHUNK) {
|
2009-04-03 13:47:43 +00:00
|
|
|
empty_size = 0;
|
|
|
|
empty_cluster = 0;
|
|
|
|
}
|
2009-04-03 14:14:19 +00:00
|
|
|
|
|
|
|
if (allowed_chunk_alloc) {
|
|
|
|
ret = do_chunk_alloc(trans, root, num_bytes +
|
|
|
|
2 * 1024 * 1024, data, 1);
|
|
|
|
allowed_chunk_alloc = 0;
|
Btrfs: find ideal block group for caching
This patch changes a few things. Hopefully the comments are helpfull, but
I'll try and be as verbose here.
Problem:
My fedora box was taking 1 minute and 21 seconds to boot with btrfs as root.
Part of this problem was we pick the first block group we can find and start
caching it, even if it may not have enough free space. The other problem is
we only search for cached block groups the first time around, which we won't
find any cached block groups because this is a newly mounted fs, so we end up
caching several block groups during bootup, which with alot of fragmentation
takes around 30-45 seconds to complete, which bogs down the system. So
Solution:
1) Don't cache block groups willy-nilly at first. Instead try and figure out
which block group has the most free, and therefore will take the least amount
of time to cache.
2) Don't be so picky about cached block groups. The other problem is once
we've filled up a cluster, if the block group isn't finished caching the next
time we try and do the allocation we'll completely ignore the cluster and
start searching from the beginning of the space, which makes us cache more
block groups, which slows us down even more. So instead of skipping block
groups that are not finished caching when we have a hint, only skip the block
group if it hasn't started caching yet.
There is one other tweak in here. Before if we allocated a chunk and still
couldn't find new space, we'd end up switching the space info to force another
chunk allocation. This could make us end up with way too many chunks, so keep
track of this particular case.
With this patch and my previous cluster fixes my fedora box now boots in 43
seconds, and according to the bootchart is not held up by our block group
caching at all.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-11 02:23:48 +00:00
|
|
|
done_chunk_alloc = 1;
|
|
|
|
} else if (!done_chunk_alloc) {
|
2009-04-03 14:14:19 +00:00
|
|
|
space_info->force_alloc = 1;
|
|
|
|
}
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (loop < LOOP_NO_EMPTY_SIZE) {
|
2009-04-03 13:47:43 +00:00
|
|
|
loop++;
|
2009-04-03 14:14:19 +00:00
|
|
|
goto search;
|
2009-04-03 13:47:43 +00:00
|
|
|
}
|
2009-04-03 14:14:19 +00:00
|
|
|
ret = -ENOSPC;
|
|
|
|
} else if (!ins->objectid) {
|
|
|
|
ret = -ENOSPC;
|
2007-06-26 16:20:46 +00:00
|
|
|
}
|
2008-03-24 19:01:56 +00:00
|
|
|
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
/* we found what we needed */
|
|
|
|
if (ins->objectid) {
|
|
|
|
if (!(data & BTRFS_BLOCK_GROUP_DATA))
|
2008-12-11 21:30:39 +00:00
|
|
|
trans->block_group = block_group->key.objectid;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
ret = 0;
|
2007-05-06 14:15:01 +00:00
|
|
|
}
|
|
|
|
|
2007-02-28 21:46:22 +00:00
|
|
|
return ret;
|
2007-02-26 15:40:21 +00:00
|
|
|
}
|
2008-04-28 19:29:52 +00:00
|
|
|
|
2009-09-11 20:12:44 +00:00
|
|
|
static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
|
|
|
|
int dump_block_groups)
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *cache;
|
2010-05-16 14:46:24 +00:00
|
|
|
int index = 0;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2009-09-11 20:12:44 +00:00
|
|
|
spin_lock(&info->lock);
|
2009-01-06 02:25:51 +00:00
|
|
|
printk(KERN_INFO "space_info has %llu free, is %sfull\n",
|
|
|
|
(unsigned long long)(info->total_bytes - info->bytes_used -
|
2009-09-11 20:12:44 +00:00
|
|
|
info->bytes_pinned - info->bytes_reserved -
|
2010-05-16 14:49:58 +00:00
|
|
|
info->bytes_readonly),
|
2009-01-06 02:25:51 +00:00
|
|
|
(info->full) ? "" : "not ");
|
2010-05-16 14:49:58 +00:00
|
|
|
printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
|
|
|
|
"reserved=%llu, may_use=%llu, readonly=%llu\n",
|
2009-04-21 19:38:29 +00:00
|
|
|
(unsigned long long)info->total_bytes,
|
2010-05-16 14:49:58 +00:00
|
|
|
(unsigned long long)info->bytes_used,
|
2009-04-21 19:38:29 +00:00
|
|
|
(unsigned long long)info->bytes_pinned,
|
2010-05-16 14:49:58 +00:00
|
|
|
(unsigned long long)info->bytes_reserved,
|
2009-04-21 19:38:29 +00:00
|
|
|
(unsigned long long)info->bytes_may_use,
|
2010-05-16 14:49:58 +00:00
|
|
|
(unsigned long long)info->bytes_readonly);
|
2009-09-11 20:12:44 +00:00
|
|
|
spin_unlock(&info->lock);
|
|
|
|
|
|
|
|
if (!dump_block_groups)
|
|
|
|
return;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
down_read(&info->groups_sem);
|
2010-05-16 14:46:24 +00:00
|
|
|
again:
|
|
|
|
list_for_each_entry(cache, &info->block_groups[index], list) {
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
spin_lock(&cache->lock);
|
2009-01-06 02:25:51 +00:00
|
|
|
printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
|
|
|
|
"%llu pinned %llu reserved\n",
|
|
|
|
(unsigned long long)cache->key.objectid,
|
|
|
|
(unsigned long long)cache->key.offset,
|
|
|
|
(unsigned long long)btrfs_block_group_used(&cache->item),
|
|
|
|
(unsigned long long)cache->pinned,
|
|
|
|
(unsigned long long)cache->reserved);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
btrfs_dump_free_space(cache, bytes);
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
}
|
2010-05-16 14:46:24 +00:00
|
|
|
if (++index < BTRFS_NR_RAID_TYPES)
|
|
|
|
goto again;
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
up_read(&info->groups_sem);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
}
|
2008-09-26 14:05:48 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 num_bytes, u64 min_alloc_size,
|
|
|
|
u64 empty_size, u64 hint_byte,
|
|
|
|
u64 search_end, struct btrfs_key *ins,
|
|
|
|
u64 data)
|
2007-02-26 15:40:21 +00:00
|
|
|
{
|
|
|
|
int ret;
|
2007-05-30 14:22:12 +00:00
|
|
|
u64 search_start = 0;
|
2008-06-25 20:01:30 +00:00
|
|
|
|
2009-02-20 16:00:09 +00:00
|
|
|
data = btrfs_get_alloc_profile(root, data);
|
2008-04-14 13:46:10 +00:00
|
|
|
again:
|
2008-05-24 18:04:53 +00:00
|
|
|
/*
|
|
|
|
* the only place that sets empty_size is btrfs_realloc_node, which
|
|
|
|
* is not called recursively on allocations
|
|
|
|
*/
|
2009-12-07 21:45:59 +00:00
|
|
|
if (empty_size || root->ref_cows)
|
2008-03-24 19:01:59 +00:00
|
|
|
ret = do_chunk_alloc(trans, root->fs_info->extent_root,
|
2008-05-24 18:04:53 +00:00
|
|
|
num_bytes + 2 * 1024 * 1024, data, 0);
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
WARN_ON(num_bytes < root->sectorsize);
|
|
|
|
ret = find_free_extent(trans, root, num_bytes, empty_size,
|
2010-05-16 14:46:25 +00:00
|
|
|
search_start, search_end, hint_byte,
|
|
|
|
ins, data);
|
2008-04-17 15:29:12 +00:00
|
|
|
|
2008-04-14 13:46:10 +00:00
|
|
|
if (ret == -ENOSPC && num_bytes > min_alloc_size) {
|
|
|
|
num_bytes = num_bytes >> 1;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
num_bytes = num_bytes & ~(root->sectorsize - 1);
|
2008-04-14 13:46:10 +00:00
|
|
|
num_bytes = max(num_bytes, min_alloc_size);
|
2008-05-24 18:04:53 +00:00
|
|
|
do_chunk_alloc(trans, root->fs_info->extent_root,
|
|
|
|
num_bytes, data, 1);
|
2008-04-14 13:46:10 +00:00
|
|
|
goto again;
|
|
|
|
}
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (ret == -ENOSPC) {
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_space_info *sinfo;
|
|
|
|
|
|
|
|
sinfo = __find_space_info(root->fs_info, data);
|
2009-01-06 02:25:51 +00:00
|
|
|
printk(KERN_ERR "btrfs allocation failed flags %llu, "
|
|
|
|
"wanted %llu\n", (unsigned long long)data,
|
|
|
|
(unsigned long long)num_bytes);
|
2009-09-11 20:12:44 +00:00
|
|
|
dump_space_info(sinfo, num_bytes, 1);
|
2008-06-25 20:01:30 +00:00
|
|
|
}
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
|
|
|
return ret;
|
2008-07-17 16:53:50 +00:00
|
|
|
}
|
|
|
|
|
2008-08-01 19:11:20 +00:00
|
|
|
int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
|
|
|
|
{
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_block_group_cache *cache;
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
int ret = 0;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
|
|
|
cache = btrfs_lookup_block_group(root->fs_info, start);
|
|
|
|
if (!cache) {
|
2009-01-06 02:25:51 +00:00
|
|
|
printk(KERN_ERR "Unable to find block group for %llu\n",
|
|
|
|
(unsigned long long)start);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
return -ENOSPC;
|
|
|
|
}
|
Btrfs: Fix free block discard calls down to the block layer
This is a patch to fix discard semantic to make Btrfs work with FTL and SSD.
We can improve FTL's performance by telling it which sectors are freed by file
system. But if we don't tell FTL the information of free sectors in proper
time, the transaction mechanism of Btrfs will be destroyed and Btrfs could not
roll back the previous transaction under the power loss condition.
There are some problems in the old implementation:
1, In __free_extent(), the pinned down extents should not be discarded.
2, In free_extents(), the free extents are all pinned, so they need to
be discarded in transaction committing time instead of free_extents().
3, The reserved extent used by log tree should be discard too.
This patch change discard behavior as follows:
1, For the extents which need to be free at once,
we discard them in update_block_group().
2, Delay discarding the pinned extent in btrfs_finish_extent_commit()
when committing transaction.
3, Remove discarding from free_extents() and __free_extent()
4, Add discard interface into btrfs_free_reserved_extent()
5, Discard sectors before updating the free space cache, otherwise,
FTL will destroy file system data.
2009-01-05 20:57:51 +00:00
|
|
|
|
|
|
|
ret = btrfs_discard_extent(root, start, len);
|
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
btrfs_add_free_space(cache, start, len);
|
2010-05-16 14:46:25 +00:00
|
|
|
update_reserved_bytes(cache, len, 0, 1);
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(cache);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2008-07-17 16:53:50 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
u64 flags, u64 owner, u64 offset,
|
|
|
|
struct btrfs_key *ins, int ref_mod)
|
2008-07-17 16:53:50 +00:00
|
|
|
{
|
|
|
|
int ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
2008-07-17 16:53:50 +00:00
|
|
|
struct btrfs_extent_item *extent_item;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_extent_inline_ref *iref;
|
2008-07-17 16:53:50 +00:00
|
|
|
struct btrfs_path *path;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct extent_buffer *leaf;
|
|
|
|
int type;
|
|
|
|
u32 size;
|
2007-08-09 00:17:12 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (parent > 0)
|
|
|
|
type = BTRFS_SHARED_DATA_REF_KEY;
|
|
|
|
else
|
|
|
|
type = BTRFS_EXTENT_DATA_REF_KEY;
|
2007-08-29 19:47:34 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
|
2007-12-11 14:25:06 +00:00
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
2008-02-01 19:51:59 +00:00
|
|
|
|
2009-03-13 15:00:37 +00:00
|
|
|
path->leave_spinning = 1;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
|
|
|
|
ins, size);
|
2007-06-28 19:57:36 +00:00
|
|
|
BUG_ON(ret);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
extent_item = btrfs_item_ptr(leaf, path->slots[0],
|
2008-02-01 19:51:59 +00:00
|
|
|
struct btrfs_extent_item);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_set_extent_refs(leaf, extent_item, ref_mod);
|
|
|
|
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
|
|
|
|
btrfs_set_extent_flags(leaf, extent_item,
|
|
|
|
flags | BTRFS_EXTENT_FLAG_DATA);
|
|
|
|
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
|
|
|
|
btrfs_set_extent_inline_ref_type(leaf, iref, type);
|
|
|
|
if (parent > 0) {
|
|
|
|
struct btrfs_shared_data_ref *ref;
|
|
|
|
ref = (struct btrfs_shared_data_ref *)(iref + 1);
|
|
|
|
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
|
|
|
|
btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
|
|
|
|
} else {
|
|
|
|
struct btrfs_extent_data_ref *ref;
|
|
|
|
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
|
|
|
|
btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
|
|
|
|
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
|
|
|
|
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
|
|
|
|
btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
|
|
|
|
}
|
2008-02-01 19:51:59 +00:00
|
|
|
|
|
|
|
btrfs_mark_buffer_dirty(path->nodes[0]);
|
2007-12-11 14:25:06 +00:00
|
|
|
btrfs_free_path(path);
|
2007-10-15 20:14:48 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
|
2008-02-04 15:10:13 +00:00
|
|
|
if (ret) {
|
2009-01-06 02:25:51 +00:00
|
|
|
printk(KERN_ERR "btrfs update block group failed for %llu "
|
|
|
|
"%llu\n", (unsigned long long)ins->objectid,
|
|
|
|
(unsigned long long)ins->offset);
|
2008-02-04 15:10:13 +00:00
|
|
|
BUG();
|
|
|
|
}
|
2008-07-17 16:53:50 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
u64 flags, struct btrfs_disk_key *key,
|
|
|
|
int level, struct btrfs_key *ins)
|
2008-07-17 16:53:50 +00:00
|
|
|
{
|
|
|
|
int ret;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
|
|
struct btrfs_extent_item *extent_item;
|
|
|
|
struct btrfs_tree_block_info *block_info;
|
|
|
|
struct btrfs_extent_inline_ref *iref;
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
|
2008-09-23 17:14:13 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
path->leave_spinning = 1;
|
|
|
|
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
|
|
|
|
ins, size);
|
2009-03-13 14:10:06 +00:00
|
|
|
BUG_ON(ret);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
extent_item = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_item);
|
|
|
|
btrfs_set_extent_refs(leaf, extent_item, 1);
|
|
|
|
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
|
|
|
|
btrfs_set_extent_flags(leaf, extent_item,
|
|
|
|
flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
|
|
|
|
block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
|
|
|
|
|
|
|
|
btrfs_set_tree_block_key(leaf, block_info, key);
|
|
|
|
btrfs_set_tree_block_level(leaf, block_info, level);
|
|
|
|
|
|
|
|
iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
|
|
|
|
if (parent > 0) {
|
|
|
|
BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
|
|
|
|
btrfs_set_extent_inline_ref_type(leaf, iref,
|
|
|
|
BTRFS_SHARED_BLOCK_REF_KEY);
|
|
|
|
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
|
|
|
|
} else {
|
|
|
|
btrfs_set_extent_inline_ref_type(leaf, iref,
|
|
|
|
BTRFS_TREE_BLOCK_REF_KEY);
|
|
|
|
btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
|
|
|
|
}
|
|
|
|
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
btrfs_free_path(path);
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
if (ret) {
|
|
|
|
printk(KERN_ERR "btrfs update block group failed for %llu "
|
|
|
|
"%llu\n", (unsigned long long)ins->objectid,
|
|
|
|
(unsigned long long)ins->offset);
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 root_objectid, u64 owner,
|
|
|
|
u64 offset, struct btrfs_key *ins)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
|
|
|
|
|
|
|
|
ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
|
|
|
|
0, root_objectid, owner, offset,
|
|
|
|
BTRFS_ADD_DELAYED_EXTENT, NULL);
|
2008-07-17 16:53:50 +00:00
|
|
|
return ret;
|
|
|
|
}
|
2008-09-05 20:13:11 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* this is used by the tree logging recovery code. It records that
|
|
|
|
* an extent has been allocated and makes sure to clear the free
|
|
|
|
* space cache bits as well
|
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 root_objectid, u64 owner, u64 offset,
|
|
|
|
struct btrfs_key *ins)
|
2008-09-05 20:13:11 +00:00
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control *caching_ctl;
|
|
|
|
u64 start = ins->objectid;
|
|
|
|
u64 num_bytes = ins->offset;
|
2008-09-05 20:13:11 +00:00
|
|
|
|
|
|
|
block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
|
2010-12-08 14:15:11 +00:00
|
|
|
cache_block_group(block_group, trans, NULL, 0);
|
2009-09-11 20:11:19 +00:00
|
|
|
caching_ctl = get_caching_control(block_group);
|
2008-09-05 20:13:11 +00:00
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
if (!caching_ctl) {
|
|
|
|
BUG_ON(!block_group_cache_done(block_group));
|
|
|
|
ret = btrfs_remove_free_space(block_group, start, num_bytes);
|
|
|
|
BUG_ON(ret);
|
|
|
|
} else {
|
|
|
|
mutex_lock(&caching_ctl->mutex);
|
|
|
|
|
|
|
|
if (start >= caching_ctl->progress) {
|
|
|
|
ret = add_excluded_extent(root, start, num_bytes);
|
|
|
|
BUG_ON(ret);
|
|
|
|
} else if (start + num_bytes <= caching_ctl->progress) {
|
|
|
|
ret = btrfs_remove_free_space(block_group,
|
|
|
|
start, num_bytes);
|
|
|
|
BUG_ON(ret);
|
|
|
|
} else {
|
|
|
|
num_bytes = caching_ctl->progress - start;
|
|
|
|
ret = btrfs_remove_free_space(block_group,
|
|
|
|
start, num_bytes);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
start = caching_ctl->progress;
|
|
|
|
num_bytes = ins->objectid + ins->offset -
|
|
|
|
caching_ctl->progress;
|
|
|
|
ret = add_excluded_extent(root, start, num_bytes);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
|
|
|
|
mutex_unlock(&caching_ctl->mutex);
|
|
|
|
put_caching_control(caching_ctl);
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = update_reserved_bytes(block_group, ins->offset, 1, 1);
|
|
|
|
BUG_ON(ret);
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
|
|
|
|
0, owner, offset, ins, 1);
|
2008-09-05 20:13:11 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2008-08-01 19:11:20 +00:00
|
|
|
struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
2009-02-12 19:09:45 +00:00
|
|
|
u64 bytenr, u32 blocksize,
|
|
|
|
int level)
|
2008-08-01 19:11:20 +00:00
|
|
|
{
|
|
|
|
struct extent_buffer *buf;
|
|
|
|
|
|
|
|
buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
|
|
|
|
if (!buf)
|
|
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
btrfs_set_header_generation(buf, trans->transid);
|
2009-02-12 19:09:45 +00:00
|
|
|
btrfs_set_buffer_lockdep_class(buf, level);
|
2008-08-01 19:11:20 +00:00
|
|
|
btrfs_tree_lock(buf);
|
|
|
|
clean_tree_block(trans, root, buf);
|
Btrfs: Change btree locking to use explicit blocking points
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.
So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.
This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.
We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.
The basic idea is:
btrfs_tree_lock() returns with the spin lock held
btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock. The buffer is
still considered locked by all of the btrfs code.
If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.
Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time. So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.
btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.
btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.
ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
|
|
|
|
|
|
|
btrfs_set_lock_blocking(buf);
|
2008-08-01 19:11:20 +00:00
|
|
|
btrfs_set_buffer_uptodate(buf);
|
Btrfs: Change btree locking to use explicit blocking points
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.
So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.
This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.
We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.
The basic idea is:
btrfs_tree_lock() returns with the spin lock held
btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock. The buffer is
still considered locked by all of the btrfs code.
If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.
Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time. So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.
btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.
btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.
ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
|
|
|
|
2008-09-11 20:17:57 +00:00
|
|
|
if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
|
2009-11-12 09:33:26 +00:00
|
|
|
/*
|
|
|
|
* we allow two log transactions at a time, use different
|
|
|
|
* EXENT bit to differentiate dirty pages.
|
|
|
|
*/
|
|
|
|
if (root->log_transid % 2 == 0)
|
|
|
|
set_extent_dirty(&root->dirty_log_pages, buf->start,
|
|
|
|
buf->start + buf->len - 1, GFP_NOFS);
|
|
|
|
else
|
|
|
|
set_extent_new(&root->dirty_log_pages, buf->start,
|
|
|
|
buf->start + buf->len - 1, GFP_NOFS);
|
2008-09-11 20:17:57 +00:00
|
|
|
} else {
|
|
|
|
set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
|
2008-08-01 19:11:20 +00:00
|
|
|
buf->start + buf->len - 1, GFP_NOFS);
|
2008-09-11 20:17:57 +00:00
|
|
|
}
|
2008-08-01 19:11:20 +00:00
|
|
|
trans->blocks_used++;
|
Btrfs: Change btree locking to use explicit blocking points
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.
So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.
This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.
We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.
The basic idea is:
btrfs_tree_lock() returns with the spin lock held
btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock. The buffer is
still considered locked by all of the btrfs code.
If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.
Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time. So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.
btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.
btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.
ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
|
|
|
/* this returns a buffer locked for blocking */
|
2008-08-01 19:11:20 +00:00
|
|
|
return buf;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
static struct btrfs_block_rsv *
|
|
|
|
use_block_rsv(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u32 blocksize)
|
|
|
|
{
|
|
|
|
struct btrfs_block_rsv *block_rsv;
|
2011-01-24 21:43:20 +00:00
|
|
|
struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
|
2010-05-16 14:46:25 +00:00
|
|
|
int ret;
|
|
|
|
|
|
|
|
block_rsv = get_block_rsv(trans, root);
|
|
|
|
|
|
|
|
if (block_rsv->size == 0) {
|
2010-10-15 20:52:49 +00:00
|
|
|
ret = reserve_metadata_bytes(trans, root, block_rsv,
|
|
|
|
blocksize, 0);
|
2011-01-24 21:43:20 +00:00
|
|
|
/*
|
|
|
|
* If we couldn't reserve metadata bytes try and use some from
|
|
|
|
* the global reserve.
|
|
|
|
*/
|
|
|
|
if (ret && block_rsv != global_rsv) {
|
|
|
|
ret = block_rsv_use_bytes(global_rsv, blocksize);
|
|
|
|
if (!ret)
|
|
|
|
return global_rsv;
|
|
|
|
return ERR_PTR(ret);
|
|
|
|
} else if (ret) {
|
2010-05-16 14:46:25 +00:00
|
|
|
return ERR_PTR(ret);
|
2011-01-24 21:43:20 +00:00
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
return block_rsv;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = block_rsv_use_bytes(block_rsv, blocksize);
|
|
|
|
if (!ret)
|
|
|
|
return block_rsv;
|
2011-01-24 21:43:20 +00:00
|
|
|
if (ret) {
|
|
|
|
WARN_ON(1);
|
|
|
|
ret = reserve_metadata_bytes(trans, root, block_rsv, blocksize,
|
|
|
|
0);
|
|
|
|
if (!ret) {
|
|
|
|
spin_lock(&block_rsv->lock);
|
|
|
|
block_rsv->size += blocksize;
|
|
|
|
spin_unlock(&block_rsv->lock);
|
|
|
|
return block_rsv;
|
|
|
|
} else if (ret && block_rsv != global_rsv) {
|
|
|
|
ret = block_rsv_use_bytes(global_rsv, blocksize);
|
|
|
|
if (!ret)
|
|
|
|
return global_rsv;
|
|
|
|
}
|
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
|
|
|
|
return ERR_PTR(-ENOSPC);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
|
|
|
|
{
|
|
|
|
block_rsv_add_bytes(block_rsv, blocksize, 0);
|
|
|
|
block_rsv_release_bytes(block_rsv, NULL, 0);
|
|
|
|
}
|
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
2010-05-16 14:46:25 +00:00
|
|
|
* finds a free extent and does all the dirty work required for allocation
|
|
|
|
* returns the key for the extent through ins, and a tree buffer for
|
|
|
|
* the first block of the extent through buf.
|
|
|
|
*
|
2007-02-26 15:40:21 +00:00
|
|
|
* returns the tree buffer or NULL.
|
|
|
|
*/
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_root *root, u32 blocksize,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
struct btrfs_disk_key *key, int level,
|
|
|
|
u64 hint, u64 empty_size)
|
2007-02-26 15:40:21 +00:00
|
|
|
{
|
2007-03-12 20:22:34 +00:00
|
|
|
struct btrfs_key ins;
|
2010-05-16 14:46:25 +00:00
|
|
|
struct btrfs_block_rsv *block_rsv;
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *buf;
|
2010-05-16 14:46:25 +00:00
|
|
|
u64 flags = 0;
|
|
|
|
int ret;
|
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
block_rsv = use_block_rsv(trans, root, blocksize);
|
|
|
|
if (IS_ERR(block_rsv))
|
|
|
|
return ERR_CAST(block_rsv);
|
|
|
|
|
|
|
|
ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
|
|
|
|
empty_size, hint, (u64)-1, &ins, 0);
|
2007-02-26 15:40:21 +00:00
|
|
|
if (ret) {
|
2010-05-16 14:46:25 +00:00
|
|
|
unuse_block_rsv(block_rsv, blocksize);
|
2007-06-22 18:16:25 +00:00
|
|
|
return ERR_PTR(ret);
|
2007-02-26 15:40:21 +00:00
|
|
|
}
|
2008-01-09 20:55:33 +00:00
|
|
|
|
2009-02-12 19:09:45 +00:00
|
|
|
buf = btrfs_init_new_buffer(trans, root, ins.objectid,
|
|
|
|
blocksize, level);
|
2010-05-16 14:46:25 +00:00
|
|
|
BUG_ON(IS_ERR(buf));
|
|
|
|
|
|
|
|
if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
|
|
|
|
if (parent == 0)
|
|
|
|
parent = ins.objectid;
|
|
|
|
flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
|
|
|
} else
|
|
|
|
BUG_ON(parent > 0);
|
|
|
|
|
|
|
|
if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
|
|
|
|
struct btrfs_delayed_extent_op *extent_op;
|
|
|
|
extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
|
|
|
|
BUG_ON(!extent_op);
|
|
|
|
if (key)
|
|
|
|
memcpy(&extent_op->key, key, sizeof(extent_op->key));
|
|
|
|
else
|
|
|
|
memset(&extent_op->key, 0, sizeof(extent_op->key));
|
|
|
|
extent_op->flags_to_set = flags;
|
|
|
|
extent_op->update_key = 1;
|
|
|
|
extent_op->update_flags = 1;
|
|
|
|
extent_op->is_data = 0;
|
|
|
|
|
|
|
|
ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
|
|
|
|
ins.offset, parent, root_objectid,
|
|
|
|
level, BTRFS_ADD_DELAYED_EXTENT,
|
|
|
|
extent_op);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
2007-02-26 15:40:21 +00:00
|
|
|
return buf;
|
|
|
|
}
|
2007-03-07 01:08:01 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
struct walk_control {
|
|
|
|
u64 refs[BTRFS_MAX_LEVEL];
|
|
|
|
u64 flags[BTRFS_MAX_LEVEL];
|
|
|
|
struct btrfs_key update_progress;
|
|
|
|
int stage;
|
|
|
|
int level;
|
|
|
|
int shared_level;
|
|
|
|
int update_ref;
|
|
|
|
int keep_locks;
|
2009-09-21 19:55:59 +00:00
|
|
|
int reada_slot;
|
|
|
|
int reada_count;
|
2009-06-28 01:07:35 +00:00
|
|
|
};
|
|
|
|
|
|
|
|
#define DROP_REFERENCE 1
|
|
|
|
#define UPDATE_BACKREF 2
|
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct walk_control *wc,
|
|
|
|
struct btrfs_path *path)
|
2007-03-27 10:33:00 +00:00
|
|
|
{
|
2009-09-21 19:55:59 +00:00
|
|
|
u64 bytenr;
|
|
|
|
u64 generation;
|
|
|
|
u64 refs;
|
2009-10-09 13:25:16 +00:00
|
|
|
u64 flags;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u32 nritems;
|
2009-09-21 19:55:59 +00:00
|
|
|
u32 blocksize;
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct extent_buffer *eb;
|
2007-03-27 10:33:00 +00:00
|
|
|
int ret;
|
2009-09-21 19:55:59 +00:00
|
|
|
int slot;
|
|
|
|
int nread = 0;
|
2007-03-27 10:33:00 +00:00
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
if (path->slots[wc->level] < wc->reada_slot) {
|
|
|
|
wc->reada_count = wc->reada_count * 2 / 3;
|
|
|
|
wc->reada_count = max(wc->reada_count, 2);
|
|
|
|
} else {
|
|
|
|
wc->reada_count = wc->reada_count * 3 / 2;
|
|
|
|
wc->reada_count = min_t(int, wc->reada_count,
|
|
|
|
BTRFS_NODEPTRS_PER_BLOCK(root));
|
|
|
|
}
|
2007-12-11 14:25:06 +00:00
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
eb = path->nodes[wc->level];
|
|
|
|
nritems = btrfs_header_nritems(eb);
|
|
|
|
blocksize = btrfs_level_size(root, wc->level - 1);
|
2009-02-04 14:27:02 +00:00
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
for (slot = path->slots[wc->level]; slot < nritems; slot++) {
|
|
|
|
if (nread >= wc->reada_count)
|
|
|
|
break;
|
2009-02-04 14:27:02 +00:00
|
|
|
|
2008-08-04 12:20:15 +00:00
|
|
|
cond_resched();
|
2009-09-21 19:55:59 +00:00
|
|
|
bytenr = btrfs_node_blockptr(eb, slot);
|
|
|
|
generation = btrfs_node_ptr_generation(eb, slot);
|
2008-08-04 12:20:15 +00:00
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
if (slot == path->slots[wc->level])
|
|
|
|
goto reada;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
if (wc->stage == UPDATE_BACKREF &&
|
|
|
|
generation <= root->root_key.offset)
|
2009-02-04 14:27:02 +00:00
|
|
|
continue;
|
|
|
|
|
2009-10-09 13:25:16 +00:00
|
|
|
/* We don't lock the tree block, it's OK to be racy here */
|
|
|
|
ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
|
|
|
|
&refs, &flags);
|
|
|
|
BUG_ON(ret);
|
|
|
|
BUG_ON(refs == 0);
|
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
if (wc->stage == DROP_REFERENCE) {
|
|
|
|
if (refs == 1)
|
|
|
|
goto reada;
|
2009-02-04 14:27:02 +00:00
|
|
|
|
2009-10-09 13:25:16 +00:00
|
|
|
if (wc->level == 1 &&
|
|
|
|
(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
|
|
|
|
continue;
|
2009-09-21 19:55:59 +00:00
|
|
|
if (!wc->update_ref ||
|
|
|
|
generation <= root->root_key.offset)
|
|
|
|
continue;
|
|
|
|
btrfs_node_key_to_cpu(eb, &key, slot);
|
|
|
|
ret = btrfs_comp_cpu_keys(&key,
|
|
|
|
&wc->update_progress);
|
|
|
|
if (ret < 0)
|
|
|
|
continue;
|
2009-10-09 13:25:16 +00:00
|
|
|
} else {
|
|
|
|
if (wc->level == 1 &&
|
|
|
|
(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
|
|
|
|
continue;
|
2007-03-27 10:33:00 +00:00
|
|
|
}
|
2009-09-21 19:55:59 +00:00
|
|
|
reada:
|
|
|
|
ret = readahead_tree_block(root, bytenr, blocksize,
|
|
|
|
generation);
|
|
|
|
if (ret)
|
2009-02-04 14:27:02 +00:00
|
|
|
break;
|
2009-09-21 19:55:59 +00:00
|
|
|
nread++;
|
2007-03-10 11:35:47 +00:00
|
|
|
}
|
2009-09-21 19:55:59 +00:00
|
|
|
wc->reada_slot = slot;
|
2007-03-10 11:35:47 +00:00
|
|
|
}
|
2009-06-28 01:07:35 +00:00
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
/*
|
2009-06-28 01:07:35 +00:00
|
|
|
* hepler to process tree block while walking down the tree.
|
|
|
|
*
|
|
|
|
* when wc->stage == UPDATE_BACKREF, this function updates
|
|
|
|
* back refs for pointers in the block.
|
|
|
|
*
|
|
|
|
* NOTE: return value 1 means we should stop walking down.
|
2008-10-29 18:49:05 +00:00
|
|
|
*/
|
2009-06-28 01:07:35 +00:00
|
|
|
static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_root *root,
|
2009-06-28 01:07:35 +00:00
|
|
|
struct btrfs_path *path,
|
2009-10-09 13:25:16 +00:00
|
|
|
struct walk_control *wc, int lookup_info)
|
2008-10-29 18:49:05 +00:00
|
|
|
{
|
2009-06-28 01:07:35 +00:00
|
|
|
int level = wc->level;
|
|
|
|
struct extent_buffer *eb = path->nodes[level];
|
|
|
|
u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
2008-10-29 18:49:05 +00:00
|
|
|
int ret;
|
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
if (wc->stage == UPDATE_BACKREF &&
|
|
|
|
btrfs_header_owner(eb) != root->root_key.objectid)
|
|
|
|
return 1;
|
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
/*
|
|
|
|
* when reference count of tree block is 1, it won't increase
|
|
|
|
* again. once full backref flag is set, we never clear it.
|
|
|
|
*/
|
2009-10-09 13:25:16 +00:00
|
|
|
if (lookup_info &&
|
|
|
|
((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
|
|
|
|
(wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
|
2009-06-28 01:07:35 +00:00
|
|
|
BUG_ON(!path->locks[level]);
|
|
|
|
ret = btrfs_lookup_extent_info(trans, root,
|
|
|
|
eb->start, eb->len,
|
|
|
|
&wc->refs[level],
|
|
|
|
&wc->flags[level]);
|
|
|
|
BUG_ON(ret);
|
|
|
|
BUG_ON(wc->refs[level] == 0);
|
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
if (wc->stage == DROP_REFERENCE) {
|
|
|
|
if (wc->refs[level] > 1)
|
|
|
|
return 1;
|
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
if (path->locks[level] && !wc->keep_locks) {
|
|
|
|
btrfs_tree_unlock(eb);
|
|
|
|
path->locks[level] = 0;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
/* wc->stage == UPDATE_BACKREF */
|
|
|
|
if (!(wc->flags[level] & flag)) {
|
|
|
|
BUG_ON(!path->locks[level]);
|
|
|
|
ret = btrfs_inc_ref(trans, root, eb, 1);
|
2008-10-29 18:49:05 +00:00
|
|
|
BUG_ON(ret);
|
2009-06-28 01:07:35 +00:00
|
|
|
ret = btrfs_dec_ref(trans, root, eb, 0);
|
|
|
|
BUG_ON(ret);
|
|
|
|
ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
|
|
|
|
eb->len, flag, 0);
|
|
|
|
BUG_ON(ret);
|
|
|
|
wc->flags[level] |= flag;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* the block is shared by multiple trees, so it's not good to
|
|
|
|
* keep the tree lock
|
|
|
|
*/
|
|
|
|
if (path->locks[level] && level > 0) {
|
|
|
|
btrfs_tree_unlock(eb);
|
|
|
|
path->locks[level] = 0;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
/*
|
|
|
|
* hepler to process tree block pointer.
|
|
|
|
*
|
|
|
|
* when wc->stage == DROP_REFERENCE, this function checks
|
|
|
|
* reference count of the block pointed to. if the block
|
|
|
|
* is shared and we need update back refs for the subtree
|
|
|
|
* rooted at the block, this function changes wc->stage to
|
|
|
|
* UPDATE_BACKREF. if the block is shared and there is no
|
|
|
|
* need to update back, this function drops the reference
|
|
|
|
* to the block.
|
|
|
|
*
|
|
|
|
* NOTE: return value 1 means we should stop walking down.
|
|
|
|
*/
|
|
|
|
static noinline int do_walk_down(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
2009-10-09 13:25:16 +00:00
|
|
|
struct walk_control *wc, int *lookup_info)
|
2009-09-21 19:55:59 +00:00
|
|
|
{
|
|
|
|
u64 bytenr;
|
|
|
|
u64 generation;
|
|
|
|
u64 parent;
|
|
|
|
u32 blocksize;
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct extent_buffer *next;
|
|
|
|
int level = wc->level;
|
|
|
|
int reada = 0;
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
generation = btrfs_node_ptr_generation(path->nodes[level],
|
|
|
|
path->slots[level]);
|
|
|
|
/*
|
|
|
|
* if the lower level block was created before the snapshot
|
|
|
|
* was created, we know there is no need to update back refs
|
|
|
|
* for the subtree
|
|
|
|
*/
|
|
|
|
if (wc->stage == UPDATE_BACKREF &&
|
2009-10-09 13:25:16 +00:00
|
|
|
generation <= root->root_key.offset) {
|
|
|
|
*lookup_info = 1;
|
2009-09-21 19:55:59 +00:00
|
|
|
return 1;
|
2009-10-09 13:25:16 +00:00
|
|
|
}
|
2009-09-21 19:55:59 +00:00
|
|
|
|
|
|
|
bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
|
|
|
|
blocksize = btrfs_level_size(root, level - 1);
|
|
|
|
|
|
|
|
next = btrfs_find_tree_block(root, bytenr, blocksize);
|
|
|
|
if (!next) {
|
|
|
|
next = btrfs_find_create_tree_block(root, bytenr, blocksize);
|
2010-03-25 12:37:12 +00:00
|
|
|
if (!next)
|
|
|
|
return -ENOMEM;
|
2009-09-21 19:55:59 +00:00
|
|
|
reada = 1;
|
|
|
|
}
|
|
|
|
btrfs_tree_lock(next);
|
|
|
|
btrfs_set_lock_blocking(next);
|
|
|
|
|
2009-10-09 13:25:16 +00:00
|
|
|
ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
|
|
|
|
&wc->refs[level - 1],
|
|
|
|
&wc->flags[level - 1]);
|
|
|
|
BUG_ON(ret);
|
|
|
|
BUG_ON(wc->refs[level - 1] == 0);
|
|
|
|
*lookup_info = 0;
|
2009-09-21 19:55:59 +00:00
|
|
|
|
2009-10-09 13:25:16 +00:00
|
|
|
if (wc->stage == DROP_REFERENCE) {
|
2009-09-21 19:55:59 +00:00
|
|
|
if (wc->refs[level - 1] > 1) {
|
2009-10-09 13:25:16 +00:00
|
|
|
if (level == 1 &&
|
|
|
|
(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
|
|
|
|
goto skip;
|
|
|
|
|
2009-09-21 19:55:59 +00:00
|
|
|
if (!wc->update_ref ||
|
|
|
|
generation <= root->root_key.offset)
|
|
|
|
goto skip;
|
|
|
|
|
|
|
|
btrfs_node_key_to_cpu(path->nodes[level], &key,
|
|
|
|
path->slots[level]);
|
|
|
|
ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
|
|
|
|
if (ret < 0)
|
|
|
|
goto skip;
|
|
|
|
|
|
|
|
wc->stage = UPDATE_BACKREF;
|
|
|
|
wc->shared_level = level - 1;
|
|
|
|
}
|
2009-10-09 13:25:16 +00:00
|
|
|
} else {
|
|
|
|
if (level == 1 &&
|
|
|
|
(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
|
|
|
|
goto skip;
|
2009-09-21 19:55:59 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (!btrfs_buffer_uptodate(next, generation)) {
|
|
|
|
btrfs_tree_unlock(next);
|
|
|
|
free_extent_buffer(next);
|
|
|
|
next = NULL;
|
2009-10-09 13:25:16 +00:00
|
|
|
*lookup_info = 1;
|
2009-09-21 19:55:59 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (!next) {
|
|
|
|
if (reada && level == 1)
|
|
|
|
reada_walk_down(trans, root, wc, path);
|
|
|
|
next = read_tree_block(root, bytenr, blocksize, generation);
|
|
|
|
btrfs_tree_lock(next);
|
|
|
|
btrfs_set_lock_blocking(next);
|
|
|
|
}
|
|
|
|
|
|
|
|
level--;
|
|
|
|
BUG_ON(level != btrfs_header_level(next));
|
|
|
|
path->nodes[level] = next;
|
|
|
|
path->slots[level] = 0;
|
|
|
|
path->locks[level] = 1;
|
|
|
|
wc->level = level;
|
|
|
|
if (wc->level == 1)
|
|
|
|
wc->reada_slot = 0;
|
|
|
|
return 0;
|
|
|
|
skip:
|
|
|
|
wc->refs[level - 1] = 0;
|
|
|
|
wc->flags[level - 1] = 0;
|
2009-10-09 13:25:16 +00:00
|
|
|
if (wc->stage == DROP_REFERENCE) {
|
|
|
|
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
|
|
|
|
parent = path->nodes[level]->start;
|
|
|
|
} else {
|
|
|
|
BUG_ON(root->root_key.objectid !=
|
|
|
|
btrfs_header_owner(path->nodes[level]));
|
|
|
|
parent = 0;
|
|
|
|
}
|
2009-09-21 19:55:59 +00:00
|
|
|
|
2009-10-09 13:25:16 +00:00
|
|
|
ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
|
|
|
|
root->root_key.objectid, level - 1, 0);
|
|
|
|
BUG_ON(ret);
|
2009-09-21 19:55:59 +00:00
|
|
|
}
|
|
|
|
btrfs_tree_unlock(next);
|
|
|
|
free_extent_buffer(next);
|
2009-10-09 13:25:16 +00:00
|
|
|
*lookup_info = 1;
|
2009-09-21 19:55:59 +00:00
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
/*
|
|
|
|
* hepler to process tree block while walking up the tree.
|
|
|
|
*
|
|
|
|
* when wc->stage == DROP_REFERENCE, this function drops
|
|
|
|
* reference count on the block.
|
|
|
|
*
|
|
|
|
* when wc->stage == UPDATE_BACKREF, this function changes
|
|
|
|
* wc->stage back to DROP_REFERENCE if we changed wc->stage
|
|
|
|
* to UPDATE_BACKREF previously while processing the block.
|
|
|
|
*
|
|
|
|
* NOTE: return value 1 means we should stop walking up.
|
|
|
|
*/
|
|
|
|
static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct walk_control *wc)
|
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
int ret;
|
2009-06-28 01:07:35 +00:00
|
|
|
int level = wc->level;
|
|
|
|
struct extent_buffer *eb = path->nodes[level];
|
|
|
|
u64 parent = 0;
|
|
|
|
|
|
|
|
if (wc->stage == UPDATE_BACKREF) {
|
|
|
|
BUG_ON(wc->shared_level < level);
|
|
|
|
if (level < wc->shared_level)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ret = find_next_key(path, level + 1, &wc->update_progress);
|
|
|
|
if (ret > 0)
|
|
|
|
wc->update_ref = 0;
|
|
|
|
|
|
|
|
wc->stage = DROP_REFERENCE;
|
|
|
|
wc->shared_level = -1;
|
|
|
|
path->slots[level] = 0;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* check reference count again if the block isn't locked.
|
|
|
|
* we should start walking down the tree again if reference
|
|
|
|
* count is one.
|
|
|
|
*/
|
|
|
|
if (!path->locks[level]) {
|
|
|
|
BUG_ON(level == 0);
|
|
|
|
btrfs_tree_lock(eb);
|
|
|
|
btrfs_set_lock_blocking(eb);
|
|
|
|
path->locks[level] = 1;
|
|
|
|
|
|
|
|
ret = btrfs_lookup_extent_info(trans, root,
|
|
|
|
eb->start, eb->len,
|
|
|
|
&wc->refs[level],
|
|
|
|
&wc->flags[level]);
|
2008-10-29 18:49:05 +00:00
|
|
|
BUG_ON(ret);
|
2009-06-28 01:07:35 +00:00
|
|
|
BUG_ON(wc->refs[level] == 0);
|
|
|
|
if (wc->refs[level] == 1) {
|
|
|
|
btrfs_tree_unlock(eb);
|
|
|
|
path->locks[level] = 0;
|
|
|
|
return 1;
|
|
|
|
}
|
2008-10-29 18:49:05 +00:00
|
|
|
}
|
2009-06-28 01:07:35 +00:00
|
|
|
}
|
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
/* wc->stage == DROP_REFERENCE */
|
|
|
|
BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
if (wc->refs[level] == 1) {
|
|
|
|
if (level == 0) {
|
|
|
|
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
|
|
|
|
ret = btrfs_dec_ref(trans, root, eb, 1);
|
|
|
|
else
|
|
|
|
ret = btrfs_dec_ref(trans, root, eb, 0);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
/* make block locked assertion in clean_tree_block happy */
|
|
|
|
if (!path->locks[level] &&
|
|
|
|
btrfs_header_generation(eb) == trans->transid) {
|
|
|
|
btrfs_tree_lock(eb);
|
|
|
|
btrfs_set_lock_blocking(eb);
|
|
|
|
path->locks[level] = 1;
|
|
|
|
}
|
|
|
|
clean_tree_block(trans, root, eb);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (eb == root->node) {
|
|
|
|
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
|
|
|
|
parent = eb->start;
|
|
|
|
else
|
|
|
|
BUG_ON(root->root_key.objectid !=
|
|
|
|
btrfs_header_owner(eb));
|
|
|
|
} else {
|
|
|
|
if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
|
|
|
|
parent = path->nodes[level + 1]->start;
|
|
|
|
else
|
|
|
|
BUG_ON(root->root_key.objectid !=
|
|
|
|
btrfs_header_owner(path->nodes[level + 1]));
|
2008-10-29 18:49:05 +00:00
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
|
2009-06-28 01:07:35 +00:00
|
|
|
out:
|
|
|
|
wc->refs[level] = 0;
|
|
|
|
wc->flags[level] = 0;
|
2010-05-16 14:46:25 +00:00
|
|
|
return 0;
|
2009-06-28 01:07:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct walk_control *wc)
|
|
|
|
{
|
|
|
|
int level = wc->level;
|
2009-10-09 13:25:16 +00:00
|
|
|
int lookup_info = 1;
|
2009-06-28 01:07:35 +00:00
|
|
|
int ret;
|
|
|
|
|
|
|
|
while (level >= 0) {
|
2009-10-09 13:25:16 +00:00
|
|
|
ret = walk_down_proc(trans, root, path, wc, lookup_info);
|
2009-06-28 01:07:35 +00:00
|
|
|
if (ret > 0)
|
|
|
|
break;
|
|
|
|
|
|
|
|
if (level == 0)
|
|
|
|
break;
|
|
|
|
|
2010-02-01 02:41:17 +00:00
|
|
|
if (path->slots[level] >=
|
|
|
|
btrfs_header_nritems(path->nodes[level]))
|
|
|
|
break;
|
|
|
|
|
2009-10-09 13:25:16 +00:00
|
|
|
ret = do_walk_down(trans, root, path, wc, &lookup_info);
|
2009-09-21 19:55:59 +00:00
|
|
|
if (ret > 0) {
|
|
|
|
path->slots[level]++;
|
|
|
|
continue;
|
2010-03-25 12:37:12 +00:00
|
|
|
} else if (ret < 0)
|
|
|
|
return ret;
|
2009-09-21 19:55:59 +00:00
|
|
|
level = wc->level;
|
2008-10-29 18:49:05 +00:00
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
|
2008-01-03 15:01:48 +00:00
|
|
|
struct btrfs_root *root,
|
2008-10-29 18:49:05 +00:00
|
|
|
struct btrfs_path *path,
|
2009-06-28 01:07:35 +00:00
|
|
|
struct walk_control *wc, int max_level)
|
2007-03-10 11:35:47 +00:00
|
|
|
{
|
2009-06-28 01:07:35 +00:00
|
|
|
int level = wc->level;
|
2007-03-10 11:35:47 +00:00
|
|
|
int ret;
|
2007-08-07 19:52:19 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
path->slots[level] = btrfs_header_nritems(path->nodes[level]);
|
|
|
|
while (level < max_level && path->nodes[level]) {
|
|
|
|
wc->level = level;
|
|
|
|
if (path->slots[level] + 1 <
|
|
|
|
btrfs_header_nritems(path->nodes[level])) {
|
|
|
|
path->slots[level]++;
|
2007-03-10 11:35:47 +00:00
|
|
|
return 0;
|
|
|
|
} else {
|
2009-06-28 01:07:35 +00:00
|
|
|
ret = walk_up_proc(trans, root, path, wc);
|
|
|
|
if (ret > 0)
|
|
|
|
return 0;
|
2009-02-04 14:27:02 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
if (path->locks[level]) {
|
|
|
|
btrfs_tree_unlock(path->nodes[level]);
|
|
|
|
path->locks[level] = 0;
|
2008-10-29 18:49:05 +00:00
|
|
|
}
|
2009-06-28 01:07:35 +00:00
|
|
|
free_extent_buffer(path->nodes[level]);
|
|
|
|
path->nodes[level] = NULL;
|
|
|
|
level++;
|
2007-03-10 11:35:47 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
2007-03-13 15:09:37 +00:00
|
|
|
/*
|
2009-06-28 01:07:35 +00:00
|
|
|
* drop a subvolume tree.
|
|
|
|
*
|
|
|
|
* this function traverses the tree freeing any blocks that only
|
|
|
|
* referenced by the tree.
|
|
|
|
*
|
|
|
|
* when a shared tree block is found. this function decreases its
|
|
|
|
* reference count by one. if update_ref is true, this function
|
|
|
|
* also make sure backrefs for the shared block and all lower level
|
|
|
|
* blocks are properly updated.
|
2007-03-13 15:09:37 +00:00
|
|
|
*/
|
2010-05-16 14:49:59 +00:00
|
|
|
int btrfs_drop_snapshot(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_rsv *block_rsv, int update_ref)
|
2007-03-10 11:35:47 +00:00
|
|
|
{
|
2007-04-02 15:20:42 +00:00
|
|
|
struct btrfs_path *path;
|
2009-06-28 01:07:35 +00:00
|
|
|
struct btrfs_trans_handle *trans;
|
|
|
|
struct btrfs_root *tree_root = root->fs_info->tree_root;
|
2007-08-07 19:52:19 +00:00
|
|
|
struct btrfs_root_item *root_item = &root->root_item;
|
2009-06-28 01:07:35 +00:00
|
|
|
struct walk_control *wc;
|
|
|
|
struct btrfs_key key;
|
|
|
|
int err = 0;
|
|
|
|
int ret;
|
|
|
|
int level;
|
2007-03-10 11:35:47 +00:00
|
|
|
|
2007-04-02 15:20:42 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
2007-03-10 11:35:47 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
wc = kzalloc(sizeof(*wc), GFP_NOFS);
|
|
|
|
BUG_ON(!wc);
|
|
|
|
|
2010-05-16 14:48:46 +00:00
|
|
|
trans = btrfs_start_transaction(tree_root, 0);
|
2010-05-16 14:49:59 +00:00
|
|
|
if (block_rsv)
|
|
|
|
trans->block_rsv = block_rsv;
|
2009-06-28 01:07:35 +00:00
|
|
|
|
2007-08-07 19:52:19 +00:00
|
|
|
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
|
2009-06-28 01:07:35 +00:00
|
|
|
level = btrfs_header_level(root->node);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
path->nodes[level] = btrfs_lock_root_node(root);
|
|
|
|
btrfs_set_lock_blocking(path->nodes[level]);
|
2007-08-07 19:52:19 +00:00
|
|
|
path->slots[level] = 0;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
path->locks[level] = 1;
|
2009-06-28 01:07:35 +00:00
|
|
|
memset(&wc->update_progress, 0,
|
|
|
|
sizeof(wc->update_progress));
|
2007-08-07 19:52:19 +00:00
|
|
|
} else {
|
|
|
|
btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
|
2009-06-28 01:07:35 +00:00
|
|
|
memcpy(&wc->update_progress, &key,
|
|
|
|
sizeof(wc->update_progress));
|
|
|
|
|
2007-08-07 20:15:09 +00:00
|
|
|
level = root_item->drop_level;
|
2009-06-28 01:07:35 +00:00
|
|
|
BUG_ON(level == 0);
|
2007-08-07 20:15:09 +00:00
|
|
|
path->lowest_level = level;
|
2009-06-28 01:07:35 +00:00
|
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
|
|
path->lowest_level = 0;
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
2007-08-07 19:52:19 +00:00
|
|
|
goto out;
|
|
|
|
}
|
2009-09-21 19:55:59 +00:00
|
|
|
WARN_ON(ret > 0);
|
2009-06-28 01:07:35 +00:00
|
|
|
|
2008-07-08 18:19:17 +00:00
|
|
|
/*
|
|
|
|
* unlock our path, this is safe because only this
|
|
|
|
* function is allowed to delete this snapshot
|
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
btrfs_unlock_up_safe(path, 0);
|
2009-06-28 01:07:35 +00:00
|
|
|
|
|
|
|
level = btrfs_header_level(root->node);
|
|
|
|
while (1) {
|
|
|
|
btrfs_tree_lock(path->nodes[level]);
|
|
|
|
btrfs_set_lock_blocking(path->nodes[level]);
|
|
|
|
|
|
|
|
ret = btrfs_lookup_extent_info(trans, root,
|
|
|
|
path->nodes[level]->start,
|
|
|
|
path->nodes[level]->len,
|
|
|
|
&wc->refs[level],
|
|
|
|
&wc->flags[level]);
|
|
|
|
BUG_ON(ret);
|
|
|
|
BUG_ON(wc->refs[level] == 0);
|
|
|
|
|
|
|
|
if (level == root_item->drop_level)
|
|
|
|
break;
|
|
|
|
|
|
|
|
btrfs_tree_unlock(path->nodes[level]);
|
|
|
|
WARN_ON(wc->refs[level] != 1);
|
|
|
|
level--;
|
|
|
|
}
|
2007-08-07 19:52:19 +00:00
|
|
|
}
|
2009-06-28 01:07:35 +00:00
|
|
|
|
|
|
|
wc->level = level;
|
|
|
|
wc->shared_level = -1;
|
|
|
|
wc->stage = DROP_REFERENCE;
|
|
|
|
wc->update_ref = update_ref;
|
|
|
|
wc->keep_locks = 0;
|
2009-09-21 19:55:59 +00:00
|
|
|
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
|
2009-06-28 01:07:35 +00:00
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (1) {
|
2009-06-28 01:07:35 +00:00
|
|
|
ret = walk_down_tree(trans, root, path, wc);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
2007-03-10 11:35:47 +00:00
|
|
|
break;
|
2009-06-28 01:07:35 +00:00
|
|
|
}
|
2007-03-13 15:09:37 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
|
|
|
|
if (ret < 0) {
|
|
|
|
err = ret;
|
2007-03-10 11:35:47 +00:00
|
|
|
break;
|
2009-06-28 01:07:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (ret > 0) {
|
|
|
|
BUG_ON(wc->stage != DROP_REFERENCE);
|
2008-06-25 20:01:31 +00:00
|
|
|
break;
|
|
|
|
}
|
2009-06-28 01:07:35 +00:00
|
|
|
|
|
|
|
if (wc->stage == DROP_REFERENCE) {
|
|
|
|
level = wc->level;
|
|
|
|
btrfs_node_key(path->nodes[level],
|
|
|
|
&root_item->drop_progress,
|
|
|
|
path->slots[level]);
|
|
|
|
root_item->drop_level = level;
|
|
|
|
}
|
|
|
|
|
|
|
|
BUG_ON(wc->level == 0);
|
2010-05-16 14:49:59 +00:00
|
|
|
if (btrfs_should_end_transaction(trans, tree_root)) {
|
2009-06-28 01:07:35 +00:00
|
|
|
ret = btrfs_update_root(trans, tree_root,
|
|
|
|
&root->root_key,
|
|
|
|
root_item);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
2010-05-16 14:49:59 +00:00
|
|
|
btrfs_end_transaction_throttle(trans, tree_root);
|
2010-05-16 14:48:46 +00:00
|
|
|
trans = btrfs_start_transaction(tree_root, 0);
|
2010-05-16 14:49:59 +00:00
|
|
|
if (block_rsv)
|
|
|
|
trans->block_rsv = block_rsv;
|
2009-03-13 14:17:05 +00:00
|
|
|
}
|
2007-03-10 11:35:47 +00:00
|
|
|
}
|
2009-06-28 01:07:35 +00:00
|
|
|
btrfs_release_path(root, path);
|
|
|
|
BUG_ON(err);
|
|
|
|
|
|
|
|
ret = btrfs_del_root(trans, tree_root, &root->root_key);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
2009-09-21 20:00:26 +00:00
|
|
|
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
|
|
|
|
ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
|
|
|
|
NULL, NULL);
|
|
|
|
BUG_ON(ret < 0);
|
|
|
|
if (ret > 0) {
|
2010-12-08 17:24:01 +00:00
|
|
|
/* if we fail to delete the orphan item this time
|
|
|
|
* around, it'll get picked up the next time.
|
|
|
|
*
|
|
|
|
* The most common failure here is just -ENOENT.
|
|
|
|
*/
|
|
|
|
btrfs_del_orphan_item(trans, tree_root,
|
|
|
|
root->root_key.objectid);
|
2009-09-21 20:00:26 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (root->in_radix) {
|
|
|
|
btrfs_free_fs_root(tree_root->fs_info, root);
|
|
|
|
} else {
|
|
|
|
free_extent_buffer(root->node);
|
|
|
|
free_extent_buffer(root->commit_root);
|
|
|
|
kfree(root);
|
|
|
|
}
|
2007-08-07 19:52:19 +00:00
|
|
|
out:
|
2010-05-16 14:49:59 +00:00
|
|
|
btrfs_end_transaction_throttle(trans, tree_root);
|
2009-06-28 01:07:35 +00:00
|
|
|
kfree(wc);
|
2007-04-02 15:20:42 +00:00
|
|
|
btrfs_free_path(path);
|
2009-06-28 01:07:35 +00:00
|
|
|
return err;
|
2007-03-10 11:35:47 +00:00
|
|
|
}
|
2007-04-26 20:46:15 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
/*
|
|
|
|
* drop subtree rooted at tree block 'node'.
|
|
|
|
*
|
|
|
|
* NOTE: this function will unlock and release tree block 'node'
|
|
|
|
*/
|
2008-10-29 18:49:05 +00:00
|
|
|
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *node,
|
|
|
|
struct extent_buffer *parent)
|
|
|
|
{
|
|
|
|
struct btrfs_path *path;
|
2009-06-28 01:07:35 +00:00
|
|
|
struct walk_control *wc;
|
2008-10-29 18:49:05 +00:00
|
|
|
int level;
|
|
|
|
int parent_level;
|
|
|
|
int ret = 0;
|
|
|
|
int wret;
|
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
|
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
wc = kzalloc(sizeof(*wc), GFP_NOFS);
|
|
|
|
BUG_ON(!wc);
|
|
|
|
|
2009-03-09 15:45:38 +00:00
|
|
|
btrfs_assert_tree_locked(parent);
|
2008-10-29 18:49:05 +00:00
|
|
|
parent_level = btrfs_header_level(parent);
|
|
|
|
extent_buffer_get(parent);
|
|
|
|
path->nodes[parent_level] = parent;
|
|
|
|
path->slots[parent_level] = btrfs_header_nritems(parent);
|
|
|
|
|
2009-03-09 15:45:38 +00:00
|
|
|
btrfs_assert_tree_locked(node);
|
2008-10-29 18:49:05 +00:00
|
|
|
level = btrfs_header_level(node);
|
|
|
|
path->nodes[level] = node;
|
|
|
|
path->slots[level] = 0;
|
2009-06-28 01:07:35 +00:00
|
|
|
path->locks[level] = 1;
|
|
|
|
|
|
|
|
wc->refs[parent_level] = 1;
|
|
|
|
wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
|
|
|
wc->level = level;
|
|
|
|
wc->shared_level = -1;
|
|
|
|
wc->stage = DROP_REFERENCE;
|
|
|
|
wc->update_ref = 0;
|
|
|
|
wc->keep_locks = 1;
|
2009-09-21 19:55:59 +00:00
|
|
|
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
|
2008-10-29 18:49:05 +00:00
|
|
|
|
|
|
|
while (1) {
|
2009-06-28 01:07:35 +00:00
|
|
|
wret = walk_down_tree(trans, root, path, wc);
|
|
|
|
if (wret < 0) {
|
2008-10-29 18:49:05 +00:00
|
|
|
ret = wret;
|
|
|
|
break;
|
2009-06-28 01:07:35 +00:00
|
|
|
}
|
2008-10-29 18:49:05 +00:00
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
wret = walk_up_tree(trans, root, path, wc, parent_level);
|
2008-10-29 18:49:05 +00:00
|
|
|
if (wret < 0)
|
|
|
|
ret = wret;
|
|
|
|
if (wret != 0)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
2009-06-28 01:07:35 +00:00
|
|
|
kfree(wc);
|
2008-10-29 18:49:05 +00:00
|
|
|
btrfs_free_path(path);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#if 0
|
2008-04-28 13:02:36 +00:00
|
|
|
static unsigned long calc_ra(unsigned long start, unsigned long last,
|
|
|
|
unsigned long nr)
|
|
|
|
{
|
|
|
|
return min(last, start + nr - 1);
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int relocate_inode_pages(struct inode *inode, u64 start,
|
2008-01-03 15:01:48 +00:00
|
|
|
u64 len)
|
2007-12-21 21:27:24 +00:00
|
|
|
{
|
|
|
|
u64 page_start;
|
|
|
|
u64 page_end;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
unsigned long first_index;
|
2007-12-21 21:27:24 +00:00
|
|
|
unsigned long last_index;
|
|
|
|
unsigned long i;
|
|
|
|
struct page *page;
|
2008-01-24 21:13:08 +00:00
|
|
|
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
|
2008-01-03 14:08:48 +00:00
|
|
|
struct file_ra_state *ra;
|
2008-07-24 15:57:52 +00:00
|
|
|
struct btrfs_ordered_extent *ordered;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
unsigned int total_read = 0;
|
|
|
|
unsigned int total_dirty = 0;
|
|
|
|
int ret = 0;
|
2008-01-03 14:08:48 +00:00
|
|
|
|
|
|
|
ra = kzalloc(sizeof(*ra), GFP_NOFS);
|
2011-02-01 09:17:35 +00:00
|
|
|
if (!ra)
|
|
|
|
return -ENOMEM;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
|
|
|
mutex_lock(&inode->i_mutex);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
first_index = start >> PAGE_CACHE_SHIFT;
|
2007-12-21 21:27:24 +00:00
|
|
|
last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
/* make sure the dirty trick played by the caller work */
|
|
|
|
ret = invalidate_inode_pages2_range(inode->i_mapping,
|
|
|
|
first_index, last_index);
|
|
|
|
if (ret)
|
|
|
|
goto out_unlock;
|
2008-04-28 13:02:36 +00:00
|
|
|
|
2008-01-03 14:08:48 +00:00
|
|
|
file_ra_state_init(ra, inode->i_mapping);
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
for (i = first_index ; i <= last_index; i++) {
|
|
|
|
if (total_read % ra->ra_pages == 0) {
|
2008-04-28 13:02:36 +00:00
|
|
|
btrfs_force_ra(inode->i_mapping, ra, NULL, i,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
calc_ra(i, last_index, ra->ra_pages));
|
2008-04-28 13:02:36 +00:00
|
|
|
}
|
|
|
|
total_read++;
|
2008-07-24 15:57:52 +00:00
|
|
|
again:
|
|
|
|
if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(1);
|
2007-12-21 21:27:24 +00:00
|
|
|
page = grab_cache_page(inode->i_mapping, i);
|
2008-05-07 15:43:44 +00:00
|
|
|
if (!page) {
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = -ENOMEM;
|
2007-12-21 21:27:24 +00:00
|
|
|
goto out_unlock;
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
if (!PageUptodate(page)) {
|
|
|
|
btrfs_readpage(NULL, page);
|
|
|
|
lock_page(page);
|
|
|
|
if (!PageUptodate(page)) {
|
|
|
|
unlock_page(page);
|
|
|
|
page_cache_release(page);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = -EIO;
|
2007-12-21 21:27:24 +00:00
|
|
|
goto out_unlock;
|
|
|
|
}
|
|
|
|
}
|
2008-04-28 19:29:52 +00:00
|
|
|
wait_on_page_writeback(page);
|
2008-07-24 15:57:52 +00:00
|
|
|
|
2007-12-21 21:27:24 +00:00
|
|
|
page_start = (u64)page->index << PAGE_CACHE_SHIFT;
|
|
|
|
page_end = page_start + PAGE_CACHE_SIZE - 1;
|
2008-01-24 21:13:08 +00:00
|
|
|
lock_extent(io_tree, page_start, page_end, GFP_NOFS);
|
2007-12-21 21:27:24 +00:00
|
|
|
|
2008-07-24 15:57:52 +00:00
|
|
|
ordered = btrfs_lookup_ordered_extent(inode, page_start);
|
|
|
|
if (ordered) {
|
|
|
|
unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
|
|
|
|
unlock_page(page);
|
|
|
|
page_cache_release(page);
|
|
|
|
btrfs_start_ordered_extent(inode, ordered, 1);
|
|
|
|
btrfs_put_ordered_extent(ordered);
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
set_page_extent_mapped(page);
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (i == first_index)
|
|
|
|
set_extent_bits(io_tree, page_start, page_end,
|
|
|
|
EXTENT_BOUNDARY, GFP_NOFS);
|
2008-12-19 15:59:04 +00:00
|
|
|
btrfs_set_extent_delalloc(inode, page_start, page_end);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
2008-05-07 15:43:44 +00:00
|
|
|
set_page_dirty(page);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
total_dirty++;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
2008-01-24 21:13:08 +00:00
|
|
|
unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
|
2007-12-21 21:27:24 +00:00
|
|
|
unlock_page(page);
|
|
|
|
page_cache_release(page);
|
|
|
|
}
|
|
|
|
|
|
|
|
out_unlock:
|
2008-04-28 19:29:52 +00:00
|
|
|
kfree(ra);
|
2007-12-21 21:27:24 +00:00
|
|
|
mutex_unlock(&inode->i_mutex);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
|
|
|
|
return ret;
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int relocate_data_extent(struct inode *reloc_inode,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_key *extent_key,
|
|
|
|
u64 offset)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
|
|
|
|
struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
|
|
|
|
struct extent_map *em;
|
2008-10-30 18:19:50 +00:00
|
|
|
u64 start = extent_key->objectid - offset;
|
|
|
|
u64 end = start + extent_key->offset - 1;
|
2008-05-08 17:26:18 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
em = alloc_extent_map(GFP_NOFS);
|
|
|
|
BUG_ON(!em || IS_ERR(em));
|
2008-05-08 17:26:18 +00:00
|
|
|
|
2008-10-30 18:19:50 +00:00
|
|
|
em->start = start;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
em->len = extent_key->offset;
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
em->block_len = extent_key->offset;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
em->block_start = extent_key->objectid;
|
|
|
|
em->bdev = root->fs_info->fs_devices->latest_bdev;
|
|
|
|
set_bit(EXTENT_FLAG_PINNED, &em->flags);
|
|
|
|
|
|
|
|
/* setup extent map to cheat btrfs_readpage */
|
2008-10-30 18:19:50 +00:00
|
|
|
lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
while (1) {
|
|
|
|
int ret;
|
2009-09-02 20:24:52 +00:00
|
|
|
write_lock(&em_tree->lock);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = add_extent_mapping(em_tree, em);
|
2009-09-02 20:24:52 +00:00
|
|
|
write_unlock(&em_tree->lock);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (ret != -EEXIST) {
|
|
|
|
free_extent_map(em);
|
2008-05-08 17:26:18 +00:00
|
|
|
break;
|
|
|
|
}
|
2008-10-30 18:19:50 +00:00
|
|
|
btrfs_drop_extent_cache(reloc_inode, start, end, 0);
|
2008-05-08 17:26:18 +00:00
|
|
|
}
|
2008-10-30 18:19:50 +00:00
|
|
|
unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
|
2008-05-08 17:26:18 +00:00
|
|
|
|
2008-10-30 18:19:50 +00:00
|
|
|
return relocate_inode_pages(reloc_inode, start, extent_key->offset);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_ref_path {
|
|
|
|
u64 extent_start;
|
|
|
|
u64 nodes[BTRFS_MAX_LEVEL];
|
|
|
|
u64 root_objectid;
|
|
|
|
u64 root_generation;
|
|
|
|
u64 owner_objectid;
|
|
|
|
u32 num_refs;
|
|
|
|
int lowest_level;
|
|
|
|
int current_level;
|
2008-10-29 18:49:05 +00:00
|
|
|
int shared_level;
|
|
|
|
|
|
|
|
struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
|
|
|
|
u64 new_nodes[BTRFS_MAX_LEVEL];
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
};
|
2008-07-08 18:19:17 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct disk_extent {
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
u64 ram_bytes;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
u64 disk_bytenr;
|
|
|
|
u64 disk_num_bytes;
|
|
|
|
u64 offset;
|
|
|
|
u64 num_bytes;
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
u8 compression;
|
|
|
|
u8 encryption;
|
|
|
|
u16 other_encoding;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
};
|
2008-01-03 14:08:48 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
static int is_cowonly_root(u64 root_objectid)
|
|
|
|
{
|
|
|
|
if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
|
|
|
|
root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
|
|
|
|
root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
|
|
|
|
root_objectid == BTRFS_DEV_TREE_OBJECTID ||
|
2008-12-11 01:32:51 +00:00
|
|
|
root_objectid == BTRFS_TREE_LOG_OBJECTID ||
|
|
|
|
root_objectid == BTRFS_CSUM_TREE_OBJECTID)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
return 1;
|
|
|
|
return 0;
|
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *extent_root,
|
|
|
|
struct btrfs_ref_path *ref_path,
|
|
|
|
int first_time)
|
|
|
|
{
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct btrfs_extent_ref *ref;
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_key found_key;
|
|
|
|
u64 bytenr;
|
|
|
|
u32 nritems;
|
|
|
|
int level;
|
|
|
|
int ret = 1;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
2008-05-08 17:26:18 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (first_time) {
|
|
|
|
ref_path->lowest_level = -1;
|
|
|
|
ref_path->current_level = -1;
|
2008-10-29 18:49:05 +00:00
|
|
|
ref_path->shared_level = -1;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
goto walk_up;
|
|
|
|
}
|
|
|
|
walk_down:
|
|
|
|
level = ref_path->current_level - 1;
|
|
|
|
while (level >= -1) {
|
|
|
|
u64 parent;
|
|
|
|
if (level < ref_path->lowest_level)
|
|
|
|
break;
|
2008-05-08 17:26:18 +00:00
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
if (level >= 0)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
bytenr = ref_path->nodes[level];
|
2009-01-06 02:25:51 +00:00
|
|
|
else
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
bytenr = ref_path->extent_start;
|
|
|
|
BUG_ON(bytenr == 0);
|
2008-05-08 17:26:18 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
parent = ref_path->nodes[level + 1];
|
|
|
|
ref_path->nodes[level + 1] = 0;
|
|
|
|
ref_path->current_level = level;
|
|
|
|
BUG_ON(parent == 0);
|
2008-05-24 18:04:53 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
key.objectid = bytenr;
|
|
|
|
key.offset = parent + 1;
|
|
|
|
key.type = BTRFS_EXTENT_REF_KEY;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
|
|
|
|
if (ret < 0)
|
2007-12-21 21:27:24 +00:00
|
|
|
goto out;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret == 0);
|
2008-07-08 18:19:17 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
if (path->slots[0] >= nritems) {
|
|
|
|
ret = btrfs_next_leaf(extent_root, path);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
if (ret > 0)
|
|
|
|
goto next;
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
}
|
2008-05-24 18:04:53 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
|
|
|
if (found_key.objectid == bytenr &&
|
2008-10-29 18:49:05 +00:00
|
|
|
found_key.type == BTRFS_EXTENT_REF_KEY) {
|
|
|
|
if (level < ref_path->shared_level)
|
|
|
|
ref_path->shared_level = level;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
goto found;
|
2008-10-29 18:49:05 +00:00
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
next:
|
|
|
|
level--;
|
|
|
|
btrfs_release_path(extent_root, path);
|
2008-10-30 18:25:28 +00:00
|
|
|
cond_resched();
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
/* reached lowest level */
|
|
|
|
ret = 1;
|
|
|
|
goto out;
|
|
|
|
walk_up:
|
|
|
|
level = ref_path->current_level;
|
|
|
|
while (level < BTRFS_MAX_LEVEL - 1) {
|
|
|
|
u64 ref_objectid;
|
2009-01-06 02:25:51 +00:00
|
|
|
|
|
|
|
if (level >= 0)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
bytenr = ref_path->nodes[level];
|
2009-01-06 02:25:51 +00:00
|
|
|
else
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
bytenr = ref_path->extent_start;
|
2009-01-06 02:25:51 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(bytenr == 0);
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
key.objectid = bytenr;
|
|
|
|
key.offset = 0;
|
|
|
|
key.type = BTRFS_EXTENT_REF_KEY;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
if (path->slots[0] >= nritems) {
|
|
|
|
ret = btrfs_next_leaf(extent_root, path);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
if (ret > 0) {
|
|
|
|
/* the extent was freed by someone */
|
|
|
|
if (ref_path->lowest_level == level)
|
|
|
|
goto out;
|
|
|
|
btrfs_release_path(extent_root, path);
|
|
|
|
goto walk_down;
|
|
|
|
}
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
|
|
|
if (found_key.objectid != bytenr ||
|
|
|
|
found_key.type != BTRFS_EXTENT_REF_KEY) {
|
|
|
|
/* the extent was freed by someone */
|
|
|
|
if (ref_path->lowest_level == level) {
|
|
|
|
ret = 1;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
btrfs_release_path(extent_root, path);
|
|
|
|
goto walk_down;
|
|
|
|
}
|
|
|
|
found:
|
|
|
|
ref = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_extent_ref);
|
|
|
|
ref_objectid = btrfs_ref_objectid(leaf, ref);
|
|
|
|
if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
if (first_time) {
|
|
|
|
level = (int)ref_objectid;
|
|
|
|
BUG_ON(level >= BTRFS_MAX_LEVEL);
|
|
|
|
ref_path->lowest_level = level;
|
|
|
|
ref_path->current_level = level;
|
|
|
|
ref_path->nodes[level] = bytenr;
|
|
|
|
} else {
|
|
|
|
WARN_ON(ref_objectid != level);
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
WARN_ON(level != -1);
|
|
|
|
}
|
|
|
|
first_time = 0;
|
2008-05-08 17:26:18 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (ref_path->lowest_level == level) {
|
|
|
|
ref_path->owner_objectid = ref_objectid;
|
|
|
|
ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
|
|
|
|
}
|
2008-05-08 17:26:18 +00:00
|
|
|
|
2008-07-08 18:19:17 +00:00
|
|
|
/*
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
* the block is tree root or the block isn't in reference
|
|
|
|
* counted tree.
|
2008-07-08 18:19:17 +00:00
|
|
|
*/
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (found_key.objectid == found_key.offset ||
|
|
|
|
is_cowonly_root(btrfs_ref_root(leaf, ref))) {
|
|
|
|
ref_path->root_objectid = btrfs_ref_root(leaf, ref);
|
|
|
|
ref_path->root_generation =
|
|
|
|
btrfs_ref_generation(leaf, ref);
|
|
|
|
if (level < 0) {
|
|
|
|
/* special reference from the tree log */
|
|
|
|
ref_path->nodes[0] = found_key.offset;
|
|
|
|
ref_path->current_level = 0;
|
|
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
2008-07-08 18:19:17 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
level++;
|
|
|
|
BUG_ON(ref_path->nodes[level] != 0);
|
|
|
|
ref_path->nodes[level] = found_key.offset;
|
|
|
|
ref_path->current_level = level;
|
2008-05-08 17:26:18 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
/*
|
|
|
|
* the reference was created in the running transaction,
|
|
|
|
* no need to continue walking up.
|
|
|
|
*/
|
|
|
|
if (btrfs_ref_generation(leaf, ref) == trans->transid) {
|
|
|
|
ref_path->root_objectid = btrfs_ref_root(leaf, ref);
|
|
|
|
ref_path->root_generation =
|
|
|
|
btrfs_ref_generation(leaf, ref);
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
2008-07-08 18:19:17 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_release_path(extent_root, path);
|
2008-10-30 18:25:28 +00:00
|
|
|
cond_resched();
|
2008-07-08 18:19:17 +00:00
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
/* reached max tree level, but no tree root found. */
|
|
|
|
BUG();
|
2007-12-21 21:27:24 +00:00
|
|
|
out:
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_free_path(path);
|
|
|
|
return ret;
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *extent_root,
|
|
|
|
struct btrfs_ref_path *ref_path,
|
|
|
|
u64 extent_start)
|
2008-05-07 15:43:44 +00:00
|
|
|
{
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
memset(ref_path, 0, sizeof(*ref_path));
|
|
|
|
ref_path->extent_start = extent_start;
|
2008-05-07 15:43:44 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
return __next_ref_path(trans, extent_root, ref_path, 1);
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *extent_root,
|
|
|
|
struct btrfs_ref_path *ref_path)
|
2007-12-21 21:27:24 +00:00
|
|
|
{
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
return __next_ref_path(trans, extent_root, ref_path, 0);
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int get_new_locations(struct inode *reloc_inode,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_key *extent_key,
|
|
|
|
u64 offset, int no_fragment,
|
|
|
|
struct disk_extent **extents,
|
|
|
|
int *nr_extents)
|
|
|
|
{
|
|
|
|
struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct btrfs_file_extent_item *fi;
|
2007-12-21 21:27:24 +00:00
|
|
|
struct extent_buffer *leaf;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct disk_extent *exts = *extents;
|
|
|
|
struct btrfs_key found_key;
|
|
|
|
u64 cur_pos;
|
|
|
|
u64 last_byte;
|
2007-12-21 21:27:24 +00:00
|
|
|
u32 nritems;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int nr = 0;
|
|
|
|
int max = *nr_extents;
|
|
|
|
int ret;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
WARN_ON(!no_fragment && *extents);
|
|
|
|
if (!exts) {
|
|
|
|
max = 1;
|
|
|
|
exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
|
|
|
|
if (!exts)
|
|
|
|
return -ENOMEM;
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
cur_pos = extent_key->objectid - offset;
|
|
|
|
last_byte = extent_key->objectid + extent_key->offset;
|
|
|
|
ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
|
|
|
|
cur_pos, 0);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
if (ret > 0) {
|
|
|
|
ret = -ENOENT;
|
|
|
|
goto out;
|
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
while (1) {
|
2007-12-21 21:27:24 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (path->slots[0] >= nritems) {
|
|
|
|
ret = btrfs_next_leaf(root, path);
|
2008-05-07 15:43:44 +00:00
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (ret > 0)
|
|
|
|
break;
|
2008-05-08 17:26:18 +00:00
|
|
|
leaf = path->nodes[0];
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (found_key.offset != cur_pos ||
|
|
|
|
found_key.type != BTRFS_EXTENT_DATA_KEY ||
|
|
|
|
found_key.objectid != reloc_inode->i_ino)
|
2007-12-21 21:27:24 +00:00
|
|
|
break;
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_file_extent_item);
|
|
|
|
if (btrfs_file_extent_type(leaf, fi) !=
|
|
|
|
BTRFS_FILE_EXTENT_REG ||
|
|
|
|
btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
|
2007-12-21 21:27:24 +00:00
|
|
|
break;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
if (nr == max) {
|
|
|
|
struct disk_extent *old = exts;
|
|
|
|
max *= 2;
|
|
|
|
exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
|
|
|
|
memcpy(exts, old, sizeof(*exts) * nr);
|
|
|
|
if (old != *extents)
|
|
|
|
kfree(old);
|
2008-05-07 15:43:44 +00:00
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
exts[nr].disk_bytenr =
|
|
|
|
btrfs_file_extent_disk_bytenr(leaf, fi);
|
|
|
|
exts[nr].disk_num_bytes =
|
|
|
|
btrfs_file_extent_disk_num_bytes(leaf, fi);
|
|
|
|
exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
|
|
|
|
exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
|
|
|
|
exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
|
|
|
|
exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
|
|
|
|
exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
|
|
|
|
fi);
|
2008-10-30 18:25:28 +00:00
|
|
|
BUG_ON(exts[nr].offset > 0);
|
|
|
|
BUG_ON(exts[nr].compression || exts[nr].encryption);
|
|
|
|
BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
|
2007-12-21 21:27:24 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
cur_pos += exts[nr].num_bytes;
|
|
|
|
nr++;
|
|
|
|
|
|
|
|
if (cur_pos + offset >= last_byte)
|
|
|
|
break;
|
|
|
|
|
|
|
|
if (no_fragment) {
|
|
|
|
ret = 1;
|
2007-12-21 21:27:24 +00:00
|
|
|
goto out;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
path->slots[0]++;
|
|
|
|
}
|
|
|
|
|
2008-12-19 15:59:04 +00:00
|
|
|
BUG_ON(cur_pos + offset > last_byte);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (cur_pos + offset < last_byte) {
|
|
|
|
ret = -ENOENT;
|
|
|
|
goto out;
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
out:
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_free_path(path);
|
|
|
|
if (ret) {
|
|
|
|
if (exts != *extents)
|
|
|
|
kfree(exts);
|
|
|
|
} else {
|
|
|
|
*extents = exts;
|
|
|
|
*nr_extents = nr;
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *extent_key,
|
|
|
|
struct btrfs_key *leaf_key,
|
|
|
|
struct btrfs_ref_path *ref_path,
|
|
|
|
struct disk_extent *new_extents,
|
|
|
|
int nr_extents)
|
|
|
|
{
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
struct btrfs_file_extent_item *fi;
|
|
|
|
struct inode *inode = NULL;
|
|
|
|
struct btrfs_key key;
|
|
|
|
u64 lock_start = 0;
|
|
|
|
u64 lock_end = 0;
|
|
|
|
u64 num_bytes;
|
|
|
|
u64 ext_offset;
|
2009-01-21 15:49:16 +00:00
|
|
|
u64 search_end = (u64)-1;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
u32 nritems;
|
2008-10-09 15:46:24 +00:00
|
|
|
int nr_scaned = 0;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int extent_locked = 0;
|
2008-10-30 18:25:28 +00:00
|
|
|
int extent_type;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int ret;
|
|
|
|
|
2008-10-09 15:46:24 +00:00
|
|
|
memcpy(&key, leaf_key, sizeof(key));
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
|
2008-10-09 15:46:24 +00:00
|
|
|
if (key.objectid < ref_path->owner_objectid ||
|
|
|
|
(key.objectid == ref_path->owner_objectid &&
|
|
|
|
key.type < BTRFS_EXTENT_DATA_KEY)) {
|
|
|
|
key.objectid = ref_path->owner_objectid;
|
|
|
|
key.type = BTRFS_EXTENT_DATA_KEY;
|
|
|
|
key.offset = 0;
|
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
while (1) {
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
next:
|
|
|
|
if (extent_locked && ret > 0) {
|
|
|
|
/*
|
|
|
|
* the file extent item was modified by someone
|
|
|
|
* before the extent got locked.
|
|
|
|
*/
|
|
|
|
unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
|
|
|
|
lock_end, GFP_NOFS);
|
|
|
|
extent_locked = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (path->slots[0] >= nritems) {
|
2008-10-09 15:46:24 +00:00
|
|
|
if (++nr_scaned > 2)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
break;
|
|
|
|
|
|
|
|
BUG_ON(extent_locked);
|
|
|
|
ret = btrfs_next_leaf(root, path);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
if (ret > 0)
|
|
|
|
break;
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
}
|
|
|
|
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
|
|
|
|
if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
|
|
|
|
if ((key.objectid > ref_path->owner_objectid) ||
|
|
|
|
(key.objectid == ref_path->owner_objectid &&
|
|
|
|
key.type > BTRFS_EXTENT_DATA_KEY) ||
|
2009-01-21 15:49:16 +00:00
|
|
|
key.offset >= search_end)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (inode && key.objectid != inode->i_ino) {
|
|
|
|
BUG_ON(extent_locked);
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
iput(inode);
|
|
|
|
inode = NULL;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (key.type != BTRFS_EXTENT_DATA_KEY) {
|
|
|
|
path->slots[0]++;
|
|
|
|
ret = 1;
|
|
|
|
goto next;
|
|
|
|
}
|
|
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_file_extent_item);
|
2008-10-30 18:25:28 +00:00
|
|
|
extent_type = btrfs_file_extent_type(leaf, fi);
|
|
|
|
if ((extent_type != BTRFS_FILE_EXTENT_REG &&
|
|
|
|
extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
(btrfs_file_extent_disk_bytenr(leaf, fi) !=
|
|
|
|
extent_key->objectid)) {
|
|
|
|
path->slots[0]++;
|
|
|
|
ret = 1;
|
|
|
|
goto next;
|
|
|
|
}
|
|
|
|
|
|
|
|
num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
|
|
|
|
ext_offset = btrfs_file_extent_offset(leaf, fi);
|
|
|
|
|
2009-01-21 15:49:16 +00:00
|
|
|
if (search_end == (u64)-1) {
|
|
|
|
search_end = key.offset - ext_offset +
|
|
|
|
btrfs_file_extent_ram_bytes(leaf, fi);
|
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
if (!extent_locked) {
|
|
|
|
lock_start = key.offset;
|
|
|
|
lock_end = lock_start + num_bytes - 1;
|
|
|
|
} else {
|
2008-10-30 18:19:50 +00:00
|
|
|
if (lock_start > key.offset ||
|
|
|
|
lock_end + 1 < key.offset + num_bytes) {
|
|
|
|
unlock_extent(&BTRFS_I(inode)->io_tree,
|
|
|
|
lock_start, lock_end, GFP_NOFS);
|
|
|
|
extent_locked = 0;
|
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (!inode) {
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
|
|
|
|
inode = btrfs_iget_locked(root->fs_info->sb,
|
|
|
|
key.objectid, root);
|
|
|
|
if (inode->i_state & I_NEW) {
|
|
|
|
BTRFS_I(inode)->root = root;
|
|
|
|
BTRFS_I(inode)->location.objectid =
|
|
|
|
key.objectid;
|
|
|
|
BTRFS_I(inode)->location.type =
|
|
|
|
BTRFS_INODE_ITEM_KEY;
|
|
|
|
BTRFS_I(inode)->location.offset = 0;
|
|
|
|
btrfs_read_locked_inode(inode);
|
|
|
|
unlock_new_inode(inode);
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* some code call btrfs_commit_transaction while
|
|
|
|
* holding the i_mutex, so we can't use mutex_lock
|
|
|
|
* here.
|
|
|
|
*/
|
|
|
|
if (is_bad_inode(inode) ||
|
|
|
|
!mutex_trylock(&inode->i_mutex)) {
|
|
|
|
iput(inode);
|
|
|
|
inode = NULL;
|
|
|
|
key.offset = (u64)-1;
|
|
|
|
goto skip;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!extent_locked) {
|
|
|
|
struct btrfs_ordered_extent *ordered;
|
|
|
|
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
|
|
|
|
lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
|
|
|
|
lock_end, GFP_NOFS);
|
|
|
|
ordered = btrfs_lookup_first_ordered_extent(inode,
|
|
|
|
lock_end);
|
|
|
|
if (ordered &&
|
|
|
|
ordered->file_offset <= lock_end &&
|
|
|
|
ordered->file_offset + ordered->len > lock_start) {
|
|
|
|
unlock_extent(&BTRFS_I(inode)->io_tree,
|
|
|
|
lock_start, lock_end, GFP_NOFS);
|
|
|
|
btrfs_start_ordered_extent(inode, ordered, 1);
|
|
|
|
btrfs_put_ordered_extent(ordered);
|
|
|
|
key.offset += num_bytes;
|
|
|
|
goto skip;
|
|
|
|
}
|
|
|
|
if (ordered)
|
|
|
|
btrfs_put_ordered_extent(ordered);
|
|
|
|
|
|
|
|
extent_locked = 1;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (nr_extents == 1) {
|
|
|
|
/* update extent pointer in place */
|
|
|
|
btrfs_set_file_extent_disk_bytenr(leaf, fi,
|
|
|
|
new_extents[0].disk_bytenr);
|
|
|
|
btrfs_set_file_extent_disk_num_bytes(leaf, fi,
|
|
|
|
new_extents[0].disk_num_bytes);
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
|
|
|
|
btrfs_drop_extent_cache(inode, key.offset,
|
|
|
|
key.offset + num_bytes - 1, 0);
|
|
|
|
|
|
|
|
ret = btrfs_inc_extent_ref(trans, root,
|
|
|
|
new_extents[0].disk_bytenr,
|
|
|
|
new_extents[0].disk_num_bytes,
|
|
|
|
leaf->start,
|
|
|
|
root->root_key.objectid,
|
|
|
|
trans->transid,
|
2008-10-09 15:46:24 +00:00
|
|
|
key.objectid);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
ret = btrfs_free_extent(trans, root,
|
|
|
|
extent_key->objectid,
|
|
|
|
extent_key->offset,
|
|
|
|
leaf->start,
|
|
|
|
btrfs_header_owner(leaf),
|
|
|
|
btrfs_header_generation(leaf),
|
2008-10-09 15:46:24 +00:00
|
|
|
key.objectid, 0);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
key.offset += num_bytes;
|
|
|
|
} else {
|
2008-10-30 18:25:28 +00:00
|
|
|
BUG_ON(1);
|
|
|
|
#if 0
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
u64 alloc_hint;
|
|
|
|
u64 extent_len;
|
|
|
|
int i;
|
|
|
|
/*
|
|
|
|
* drop old extent pointer at first, then insert the
|
|
|
|
* new pointers one bye one
|
|
|
|
*/
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
ret = btrfs_drop_extents(trans, root, inode, key.offset,
|
|
|
|
key.offset + num_bytes,
|
|
|
|
key.offset, &alloc_hint);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
for (i = 0; i < nr_extents; i++) {
|
|
|
|
if (ext_offset >= new_extents[i].num_bytes) {
|
|
|
|
ext_offset -= new_extents[i].num_bytes;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
extent_len = min(new_extents[i].num_bytes -
|
|
|
|
ext_offset, num_bytes);
|
|
|
|
|
|
|
|
ret = btrfs_insert_empty_item(trans, root,
|
|
|
|
path, &key,
|
|
|
|
sizeof(*fi));
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
|
|
struct btrfs_file_extent_item);
|
|
|
|
btrfs_set_file_extent_generation(leaf, fi,
|
|
|
|
trans->transid);
|
|
|
|
btrfs_set_file_extent_type(leaf, fi,
|
|
|
|
BTRFS_FILE_EXTENT_REG);
|
|
|
|
btrfs_set_file_extent_disk_bytenr(leaf, fi,
|
|
|
|
new_extents[i].disk_bytenr);
|
|
|
|
btrfs_set_file_extent_disk_num_bytes(leaf, fi,
|
|
|
|
new_extents[i].disk_num_bytes);
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
btrfs_set_file_extent_ram_bytes(leaf, fi,
|
|
|
|
new_extents[i].ram_bytes);
|
|
|
|
|
|
|
|
btrfs_set_file_extent_compression(leaf, fi,
|
|
|
|
new_extents[i].compression);
|
|
|
|
btrfs_set_file_extent_encryption(leaf, fi,
|
|
|
|
new_extents[i].encryption);
|
|
|
|
btrfs_set_file_extent_other_encoding(leaf, fi,
|
|
|
|
new_extents[i].other_encoding);
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_set_file_extent_num_bytes(leaf, fi,
|
|
|
|
extent_len);
|
|
|
|
ext_offset += new_extents[i].offset;
|
|
|
|
btrfs_set_file_extent_offset(leaf, fi,
|
|
|
|
ext_offset);
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
|
|
|
|
btrfs_drop_extent_cache(inode, key.offset,
|
|
|
|
key.offset + extent_len - 1, 0);
|
|
|
|
|
|
|
|
ret = btrfs_inc_extent_ref(trans, root,
|
|
|
|
new_extents[i].disk_bytenr,
|
|
|
|
new_extents[i].disk_num_bytes,
|
|
|
|
leaf->start,
|
|
|
|
root->root_key.objectid,
|
2008-10-09 15:46:24 +00:00
|
|
|
trans->transid, key.objectid);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
|
2008-10-09 15:46:29 +00:00
|
|
|
inode_add_bytes(inode, extent_len);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
ext_offset = 0;
|
|
|
|
num_bytes -= extent_len;
|
|
|
|
key.offset += extent_len;
|
|
|
|
|
|
|
|
if (num_bytes == 0)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
BUG_ON(i >= nr_extents);
|
2008-10-30 18:25:28 +00:00
|
|
|
#endif
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (extent_locked) {
|
|
|
|
unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
|
|
|
|
lock_end, GFP_NOFS);
|
|
|
|
extent_locked = 0;
|
|
|
|
}
|
|
|
|
skip:
|
|
|
|
if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
|
2009-01-21 15:49:16 +00:00
|
|
|
key.offset >= search_end)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
break;
|
|
|
|
|
|
|
|
cond_resched();
|
|
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
if (inode) {
|
|
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
if (extent_locked) {
|
|
|
|
unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
|
|
|
|
lock_end, GFP_NOFS);
|
|
|
|
}
|
|
|
|
iput(inode);
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf, u64 orig_start)
|
|
|
|
{
|
|
|
|
int level;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
BUG_ON(btrfs_header_generation(buf) != trans->transid);
|
|
|
|
BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
|
|
|
|
|
|
|
|
level = btrfs_header_level(buf);
|
|
|
|
if (level == 0) {
|
|
|
|
struct btrfs_leaf_ref *ref;
|
|
|
|
struct btrfs_leaf_ref *orig_ref;
|
|
|
|
|
|
|
|
orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
|
|
|
|
if (!orig_ref)
|
|
|
|
return -ENOENT;
|
|
|
|
|
|
|
|
ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
|
|
|
|
if (!ref) {
|
|
|
|
btrfs_free_leaf_ref(root, orig_ref);
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
|
|
|
ref->nritems = orig_ref->nritems;
|
|
|
|
memcpy(ref->extents, orig_ref->extents,
|
|
|
|
sizeof(ref->extents[0]) * ref->nritems);
|
|
|
|
|
|
|
|
btrfs_free_leaf_ref(root, orig_ref);
|
|
|
|
|
|
|
|
ref->root_gen = trans->transid;
|
|
|
|
ref->bytenr = buf->start;
|
|
|
|
ref->owner = btrfs_header_owner(buf);
|
|
|
|
ref->generation = btrfs_header_generation(buf);
|
2009-02-04 14:27:02 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = btrfs_add_leaf_ref(root, ref, 0);
|
|
|
|
WARN_ON(ret);
|
|
|
|
btrfs_free_leaf_ref(root, ref);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int invalidate_extent_cache(struct btrfs_root *root,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct extent_buffer *leaf,
|
|
|
|
struct btrfs_block_group_cache *group,
|
|
|
|
struct btrfs_root *target_root)
|
|
|
|
{
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct inode *inode = NULL;
|
|
|
|
struct btrfs_file_extent_item *fi;
|
2010-02-03 19:33:23 +00:00
|
|
|
struct extent_state *cached_state = NULL;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
u64 num_bytes;
|
|
|
|
u64 skip_objectid = 0;
|
|
|
|
u32 nritems;
|
|
|
|
u32 i;
|
|
|
|
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
for (i = 0; i < nritems; i++) {
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, i);
|
|
|
|
if (key.objectid == skip_objectid ||
|
|
|
|
key.type != BTRFS_EXTENT_DATA_KEY)
|
|
|
|
continue;
|
|
|
|
fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
|
|
|
|
if (btrfs_file_extent_type(leaf, fi) ==
|
|
|
|
BTRFS_FILE_EXTENT_INLINE)
|
|
|
|
continue;
|
|
|
|
if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
|
|
|
|
continue;
|
|
|
|
if (!inode || inode->i_ino != key.objectid) {
|
|
|
|
iput(inode);
|
|
|
|
inode = btrfs_ilookup(target_root->fs_info->sb,
|
|
|
|
key.objectid, target_root, 1);
|
|
|
|
}
|
|
|
|
if (!inode) {
|
|
|
|
skip_objectid = key.objectid;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
|
|
|
|
|
2010-02-03 19:33:23 +00:00
|
|
|
lock_extent_bits(&BTRFS_I(inode)->io_tree, key.offset,
|
|
|
|
key.offset + num_bytes - 1, 0, &cached_state,
|
|
|
|
GFP_NOFS);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
btrfs_drop_extent_cache(inode, key.offset,
|
|
|
|
key.offset + num_bytes - 1, 1);
|
2010-02-03 19:33:23 +00:00
|
|
|
unlock_extent_cached(&BTRFS_I(inode)->io_tree, key.offset,
|
|
|
|
key.offset + num_bytes - 1, &cached_state,
|
|
|
|
GFP_NOFS);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
cond_resched();
|
|
|
|
}
|
|
|
|
iput(inode);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *leaf,
|
|
|
|
struct btrfs_block_group_cache *group,
|
|
|
|
struct inode *reloc_inode)
|
|
|
|
{
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_key extent_key;
|
|
|
|
struct btrfs_file_extent_item *fi;
|
|
|
|
struct btrfs_leaf_ref *ref;
|
|
|
|
struct disk_extent *new_extent;
|
|
|
|
u64 bytenr;
|
|
|
|
u64 num_bytes;
|
|
|
|
u32 nritems;
|
|
|
|
u32 i;
|
|
|
|
int ext_index;
|
|
|
|
int nr_extent;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
|
|
|
|
BUG_ON(!new_extent);
|
|
|
|
|
|
|
|
ref = btrfs_lookup_leaf_ref(root, leaf->start);
|
|
|
|
BUG_ON(!ref);
|
|
|
|
|
|
|
|
ext_index = -1;
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
for (i = 0; i < nritems; i++) {
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, i);
|
|
|
|
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
|
|
|
|
continue;
|
|
|
|
fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
|
|
|
|
if (btrfs_file_extent_type(leaf, fi) ==
|
|
|
|
BTRFS_FILE_EXTENT_INLINE)
|
|
|
|
continue;
|
|
|
|
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
|
|
|
|
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
|
|
|
|
if (bytenr == 0)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
ext_index++;
|
|
|
|
if (bytenr >= group->key.objectid + group->key.offset ||
|
|
|
|
bytenr + num_bytes <= group->key.objectid)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
extent_key.objectid = bytenr;
|
|
|
|
extent_key.offset = num_bytes;
|
|
|
|
extent_key.type = BTRFS_EXTENT_ITEM_KEY;
|
|
|
|
nr_extent = 1;
|
|
|
|
ret = get_new_locations(reloc_inode, &extent_key,
|
|
|
|
group->key.objectid, 1,
|
|
|
|
&new_extent, &nr_extent);
|
|
|
|
if (ret > 0)
|
|
|
|
continue;
|
|
|
|
BUG_ON(ret < 0);
|
|
|
|
|
|
|
|
BUG_ON(ref->extents[ext_index].bytenr != bytenr);
|
|
|
|
BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
|
|
|
|
ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
|
|
|
|
ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
|
|
|
|
|
|
|
|
btrfs_set_file_extent_disk_bytenr(leaf, fi,
|
|
|
|
new_extent->disk_bytenr);
|
|
|
|
btrfs_set_file_extent_disk_num_bytes(leaf, fi,
|
|
|
|
new_extent->disk_num_bytes);
|
|
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
|
|
|
|
ret = btrfs_inc_extent_ref(trans, root,
|
|
|
|
new_extent->disk_bytenr,
|
|
|
|
new_extent->disk_num_bytes,
|
|
|
|
leaf->start,
|
|
|
|
root->root_key.objectid,
|
2008-10-09 15:46:24 +00:00
|
|
|
trans->transid, key.objectid);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret);
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = btrfs_free_extent(trans, root,
|
|
|
|
bytenr, num_bytes, leaf->start,
|
|
|
|
btrfs_header_owner(leaf),
|
|
|
|
btrfs_header_generation(leaf),
|
2008-10-09 15:46:24 +00:00
|
|
|
key.objectid, 0);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
cond_resched();
|
|
|
|
}
|
|
|
|
kfree(new_extent);
|
|
|
|
BUG_ON(ext_index + 1 != ref->nritems);
|
|
|
|
btrfs_free_leaf_ref(root, ref);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
{
|
|
|
|
struct btrfs_root *reloc_root;
|
2008-10-29 18:49:05 +00:00
|
|
|
int ret;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
if (root->reloc_root) {
|
|
|
|
reloc_root = root->reloc_root;
|
|
|
|
root->reloc_root = NULL;
|
|
|
|
list_add(&reloc_root->dead_list,
|
|
|
|
&root->fs_info->dead_reloc_roots);
|
2008-10-29 18:49:05 +00:00
|
|
|
|
|
|
|
btrfs_set_root_bytenr(&reloc_root->root_item,
|
|
|
|
reloc_root->node->start);
|
|
|
|
btrfs_set_root_level(&root->root_item,
|
|
|
|
btrfs_header_level(reloc_root->node));
|
|
|
|
memset(&reloc_root->root_item.drop_progress, 0,
|
|
|
|
sizeof(struct btrfs_disk_key));
|
|
|
|
reloc_root->root_item.drop_level = 0;
|
|
|
|
|
|
|
|
ret = btrfs_update_root(trans, root->fs_info->tree_root,
|
|
|
|
&reloc_root->root_key,
|
|
|
|
&reloc_root->root_item);
|
|
|
|
BUG_ON(ret);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_trans_handle *trans;
|
|
|
|
struct btrfs_root *reloc_root;
|
|
|
|
struct btrfs_root *prev_root = NULL;
|
|
|
|
struct list_head dead_roots;
|
|
|
|
int ret;
|
|
|
|
unsigned long nr;
|
|
|
|
|
|
|
|
INIT_LIST_HEAD(&dead_roots);
|
|
|
|
list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
|
|
|
|
|
|
|
|
while (!list_empty(&dead_roots)) {
|
|
|
|
reloc_root = list_entry(dead_roots.prev,
|
|
|
|
struct btrfs_root, dead_list);
|
|
|
|
list_del_init(&reloc_root->dead_list);
|
|
|
|
|
|
|
|
BUG_ON(reloc_root->commit_root != NULL);
|
|
|
|
while (1) {
|
|
|
|
trans = btrfs_join_transaction(root, 1);
|
2011-01-25 02:51:38 +00:00
|
|
|
BUG_ON(IS_ERR(trans));
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
mutex_lock(&root->fs_info->drop_mutex);
|
|
|
|
ret = btrfs_drop_snapshot(trans, reloc_root);
|
|
|
|
if (ret != -EAGAIN)
|
|
|
|
break;
|
|
|
|
mutex_unlock(&root->fs_info->drop_mutex);
|
|
|
|
|
|
|
|
nr = trans->blocks_used;
|
|
|
|
ret = btrfs_end_transaction(trans, root);
|
|
|
|
BUG_ON(ret);
|
|
|
|
btrfs_btree_balance_dirty(root, nr);
|
|
|
|
}
|
|
|
|
|
|
|
|
free_extent_buffer(reloc_root->node);
|
|
|
|
|
|
|
|
ret = btrfs_del_root(trans, root->fs_info->tree_root,
|
|
|
|
&reloc_root->root_key);
|
|
|
|
BUG_ON(ret);
|
|
|
|
mutex_unlock(&root->fs_info->drop_mutex);
|
|
|
|
|
|
|
|
nr = trans->blocks_used;
|
|
|
|
ret = btrfs_end_transaction(trans, root);
|
|
|
|
BUG_ON(ret);
|
|
|
|
btrfs_btree_balance_dirty(root, nr);
|
|
|
|
|
|
|
|
kfree(prev_root);
|
|
|
|
prev_root = reloc_root;
|
|
|
|
}
|
|
|
|
if (prev_root) {
|
|
|
|
btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
|
|
|
|
kfree(prev_root);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_add_dead_reloc_root(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_root *reloc_root;
|
|
|
|
struct btrfs_trans_handle *trans;
|
|
|
|
struct btrfs_key location;
|
|
|
|
int found;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
mutex_lock(&root->fs_info->tree_reloc_mutex);
|
|
|
|
ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
|
|
|
|
BUG_ON(ret);
|
|
|
|
found = !list_empty(&root->fs_info->dead_reloc_roots);
|
|
|
|
mutex_unlock(&root->fs_info->tree_reloc_mutex);
|
|
|
|
|
|
|
|
if (found) {
|
|
|
|
trans = btrfs_start_transaction(root, 1);
|
|
|
|
BUG_ON(!trans);
|
|
|
|
ret = btrfs_commit_transaction(trans, root);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
|
|
|
|
location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
|
|
|
|
location.offset = (u64)-1;
|
|
|
|
location.type = BTRFS_ROOT_ITEM_KEY;
|
|
|
|
|
|
|
|
reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
|
|
|
|
BUG_ON(!reloc_root);
|
|
|
|
btrfs_orphan_cleanup(reloc_root);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_root *reloc_root;
|
|
|
|
struct extent_buffer *eb;
|
|
|
|
struct btrfs_root_item *root_item;
|
|
|
|
struct btrfs_key root_key;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
BUG_ON(!root->ref_cows);
|
|
|
|
if (root->reloc_root)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
|
|
|
|
BUG_ON(!root_item);
|
|
|
|
|
|
|
|
ret = btrfs_copy_root(trans, root, root->commit_root,
|
|
|
|
&eb, BTRFS_TREE_RELOC_OBJECTID);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
|
|
|
|
root_key.offset = root->root_key.objectid;
|
|
|
|
root_key.type = BTRFS_ROOT_ITEM_KEY;
|
|
|
|
|
|
|
|
memcpy(root_item, &root->root_item, sizeof(root_item));
|
|
|
|
btrfs_set_root_refs(root_item, 0);
|
|
|
|
btrfs_set_root_bytenr(root_item, eb->start);
|
|
|
|
btrfs_set_root_level(root_item, btrfs_header_level(eb));
|
2008-10-29 18:49:05 +00:00
|
|
|
btrfs_set_root_generation(root_item, trans->transid);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
btrfs_tree_unlock(eb);
|
|
|
|
free_extent_buffer(eb);
|
|
|
|
|
|
|
|
ret = btrfs_insert_root(trans, root->fs_info->tree_root,
|
|
|
|
&root_key, root_item);
|
|
|
|
BUG_ON(ret);
|
|
|
|
kfree(root_item);
|
|
|
|
|
|
|
|
reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
|
|
|
|
&root_key);
|
|
|
|
BUG_ON(!reloc_root);
|
|
|
|
reloc_root->last_trans = trans->transid;
|
|
|
|
reloc_root->commit_root = NULL;
|
|
|
|
reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
|
|
|
|
|
|
|
|
root->reloc_root = reloc_root;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Core function of space balance.
|
|
|
|
*
|
|
|
|
* The idea is using reloc trees to relocate tree blocks in reference
|
2008-10-29 18:49:05 +00:00
|
|
|
* counted roots. There is one reloc tree for each subvol, and all
|
|
|
|
* reloc trees share same root key objectid. Reloc trees are snapshots
|
|
|
|
* of the latest committed roots of subvols (root->commit_root).
|
|
|
|
*
|
|
|
|
* To relocate a tree block referenced by a subvol, there are two steps.
|
|
|
|
* COW the block through subvol's reloc tree, then update block pointer
|
|
|
|
* in the subvol to point to the new block. Since all reloc trees share
|
|
|
|
* same root key objectid, doing special handing for tree blocks owned
|
|
|
|
* by them is easy. Once a tree block has been COWed in one reloc tree,
|
|
|
|
* we can use the resulting new block directly when the same block is
|
|
|
|
* required to COW again through other reloc trees. By this way, relocated
|
|
|
|
* tree blocks are shared between reloc trees, so they are also shared
|
|
|
|
* between subvols.
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
*/
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *first_key,
|
|
|
|
struct btrfs_ref_path *ref_path,
|
|
|
|
struct btrfs_block_group_cache *group,
|
|
|
|
struct inode *reloc_inode)
|
|
|
|
{
|
|
|
|
struct btrfs_root *reloc_root;
|
|
|
|
struct extent_buffer *eb = NULL;
|
|
|
|
struct btrfs_key *keys;
|
|
|
|
u64 *nodes;
|
|
|
|
int level;
|
2008-10-29 18:49:05 +00:00
|
|
|
int shared_level;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int lowest_level = 0;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
|
|
|
|
lowest_level = ref_path->owner_objectid;
|
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
if (!root->ref_cows) {
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
path->lowest_level = lowest_level;
|
|
|
|
ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
|
|
|
|
BUG_ON(ret < 0);
|
|
|
|
path->lowest_level = 0;
|
|
|
|
btrfs_release_path(root, path);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
mutex_lock(&root->fs_info->tree_reloc_mutex);
|
|
|
|
ret = init_reloc_tree(trans, root);
|
|
|
|
BUG_ON(ret);
|
|
|
|
reloc_root = root->reloc_root;
|
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
shared_level = ref_path->shared_level;
|
|
|
|
ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
keys = ref_path->node_keys;
|
|
|
|
nodes = ref_path->new_nodes;
|
|
|
|
memset(&keys[shared_level + 1], 0,
|
|
|
|
sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
|
|
|
|
memset(&nodes[shared_level + 1], 0,
|
|
|
|
sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
if (nodes[lowest_level] == 0) {
|
|
|
|
path->lowest_level = lowest_level;
|
|
|
|
ret = btrfs_search_slot(trans, reloc_root, first_key, path,
|
|
|
|
0, 1);
|
|
|
|
BUG_ON(ret);
|
|
|
|
for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
|
|
|
|
eb = path->nodes[level];
|
|
|
|
if (!eb || eb == reloc_root->node)
|
|
|
|
break;
|
|
|
|
nodes[level] = eb->start;
|
|
|
|
if (level == 0)
|
|
|
|
btrfs_item_key_to_cpu(eb, &keys[level], 0);
|
|
|
|
else
|
|
|
|
btrfs_node_key_to_cpu(eb, &keys[level], 0);
|
|
|
|
}
|
2008-11-18 02:11:30 +00:00
|
|
|
if (nodes[0] &&
|
|
|
|
ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
|
2008-10-29 18:49:05 +00:00
|
|
|
eb = path->nodes[0];
|
|
|
|
ret = replace_extents_in_leaf(trans, reloc_root, eb,
|
|
|
|
group, reloc_inode);
|
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
btrfs_release_path(reloc_root, path);
|
|
|
|
} else {
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
|
2008-10-29 18:49:05 +00:00
|
|
|
lowest_level);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
BUG_ON(ret);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* replace tree blocks in the fs tree with tree blocks in
|
|
|
|
* the reloc tree.
|
|
|
|
*/
|
|
|
|
ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
|
|
|
|
BUG_ON(ret < 0);
|
|
|
|
|
|
|
|
if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
|
2008-10-29 18:49:05 +00:00
|
|
|
ret = btrfs_search_slot(trans, reloc_root, first_key, path,
|
|
|
|
0, 0);
|
|
|
|
BUG_ON(ret);
|
|
|
|
extent_buffer_get(path->nodes[0]);
|
|
|
|
eb = path->nodes[0];
|
|
|
|
btrfs_release_path(reloc_root, path);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = invalidate_extent_cache(reloc_root, eb, group, root);
|
|
|
|
BUG_ON(ret);
|
|
|
|
free_extent_buffer(eb);
|
|
|
|
}
|
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
mutex_unlock(&root->fs_info->tree_reloc_mutex);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
path->lowest_level = 0;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *first_key,
|
|
|
|
struct btrfs_ref_path *ref_path)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = relocate_one_path(trans, root, path, first_key,
|
|
|
|
ref_path, NULL, NULL);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *extent_root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *extent_key)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
|
|
|
|
if (ret)
|
|
|
|
goto out;
|
|
|
|
ret = btrfs_del_item(trans, extent_root, path);
|
|
|
|
out:
|
|
|
|
btrfs_release_path(extent_root, path);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_ref_path *ref_path)
|
|
|
|
{
|
|
|
|
struct btrfs_key root_key;
|
|
|
|
|
|
|
|
root_key.objectid = ref_path->root_objectid;
|
|
|
|
root_key.type = BTRFS_ROOT_ITEM_KEY;
|
|
|
|
if (is_cowonly_root(ref_path->root_objectid))
|
|
|
|
root_key.offset = 0;
|
|
|
|
else
|
|
|
|
root_key.offset = (u64)-1;
|
|
|
|
|
|
|
|
return btrfs_read_fs_root_no_name(fs_info, &root_key);
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static noinline int relocate_one_extent(struct btrfs_root *extent_root,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *extent_key,
|
|
|
|
struct btrfs_block_group_cache *group,
|
|
|
|
struct inode *reloc_inode, int pass)
|
|
|
|
{
|
|
|
|
struct btrfs_trans_handle *trans;
|
|
|
|
struct btrfs_root *found_root;
|
|
|
|
struct btrfs_ref_path *ref_path = NULL;
|
|
|
|
struct disk_extent *new_extents = NULL;
|
|
|
|
int nr_extents = 0;
|
|
|
|
int loops;
|
|
|
|
int ret;
|
|
|
|
int level;
|
|
|
|
struct btrfs_key first_key;
|
|
|
|
u64 prev_block = 0;
|
|
|
|
|
|
|
|
|
|
|
|
trans = btrfs_start_transaction(extent_root, 1);
|
|
|
|
BUG_ON(!trans);
|
|
|
|
|
|
|
|
if (extent_key->objectid == 0) {
|
|
|
|
ret = del_extent_zero(trans, extent_root, path, extent_key);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
|
|
|
|
if (!ref_path) {
|
2009-01-06 02:25:51 +00:00
|
|
|
ret = -ENOMEM;
|
|
|
|
goto out;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
for (loops = 0; ; loops++) {
|
|
|
|
if (loops == 0) {
|
|
|
|
ret = btrfs_first_ref_path(trans, extent_root, ref_path,
|
|
|
|
extent_key->objectid);
|
|
|
|
} else {
|
|
|
|
ret = btrfs_next_ref_path(trans, extent_root, ref_path);
|
|
|
|
}
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
if (ret > 0)
|
|
|
|
break;
|
|
|
|
|
|
|
|
if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
|
|
|
|
ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
found_root = read_ref_root(extent_root->fs_info, ref_path);
|
|
|
|
BUG_ON(!found_root);
|
|
|
|
/*
|
|
|
|
* for reference counted tree, only process reference paths
|
|
|
|
* rooted at the latest committed root.
|
|
|
|
*/
|
|
|
|
if (found_root->ref_cows &&
|
|
|
|
ref_path->root_generation != found_root->root_key.offset)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
if (pass == 0) {
|
|
|
|
/*
|
|
|
|
* copy data extents to new locations
|
|
|
|
*/
|
|
|
|
u64 group_start = group->key.objectid;
|
|
|
|
ret = relocate_data_extent(reloc_inode,
|
|
|
|
extent_key,
|
|
|
|
group_start);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
level = 0;
|
|
|
|
} else {
|
|
|
|
level = ref_path->owner_objectid;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (prev_block != ref_path->nodes[level]) {
|
|
|
|
struct extent_buffer *eb;
|
|
|
|
u64 block_start = ref_path->nodes[level];
|
|
|
|
u64 block_size = btrfs_level_size(found_root, level);
|
|
|
|
|
|
|
|
eb = read_tree_block(found_root, block_start,
|
|
|
|
block_size, 0);
|
|
|
|
btrfs_tree_lock(eb);
|
|
|
|
BUG_ON(level != btrfs_header_level(eb));
|
|
|
|
|
|
|
|
if (level == 0)
|
|
|
|
btrfs_item_key_to_cpu(eb, &first_key, 0);
|
|
|
|
else
|
|
|
|
btrfs_node_key_to_cpu(eb, &first_key, 0);
|
|
|
|
|
|
|
|
btrfs_tree_unlock(eb);
|
|
|
|
free_extent_buffer(eb);
|
|
|
|
prev_block = block_start;
|
|
|
|
}
|
|
|
|
|
2009-02-12 19:14:53 +00:00
|
|
|
mutex_lock(&extent_root->fs_info->trans_mutex);
|
2008-12-12 15:03:26 +00:00
|
|
|
btrfs_record_root_in_trans(found_root);
|
2009-02-12 19:14:53 +00:00
|
|
|
mutex_unlock(&extent_root->fs_info->trans_mutex);
|
2008-12-12 15:03:26 +00:00
|
|
|
if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
|
|
|
|
/*
|
|
|
|
* try to update data extent references while
|
|
|
|
* keeping metadata shared between snapshots.
|
|
|
|
*/
|
|
|
|
if (pass == 1) {
|
|
|
|
ret = relocate_one_path(trans, found_root,
|
|
|
|
path, &first_key, ref_path,
|
|
|
|
group, reloc_inode);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
continue;
|
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
/*
|
|
|
|
* use fallback method to process the remaining
|
|
|
|
* references.
|
|
|
|
*/
|
|
|
|
if (!new_extents) {
|
|
|
|
u64 group_start = group->key.objectid;
|
2008-10-30 18:25:28 +00:00
|
|
|
new_extents = kmalloc(sizeof(*new_extents),
|
|
|
|
GFP_NOFS);
|
|
|
|
nr_extents = 1;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = get_new_locations(reloc_inode,
|
|
|
|
extent_key,
|
2008-10-30 18:25:28 +00:00
|
|
|
group_start, 1,
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
&new_extents,
|
|
|
|
&nr_extents);
|
2008-10-30 18:25:28 +00:00
|
|
|
if (ret)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
ret = replace_one_extent(trans, found_root,
|
|
|
|
path, extent_key,
|
|
|
|
&first_key, ref_path,
|
|
|
|
new_extents, nr_extents);
|
2008-12-12 15:03:26 +00:00
|
|
|
} else {
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
ret = relocate_tree_block(trans, found_root, path,
|
|
|
|
&first_key, ref_path);
|
|
|
|
}
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
|
|
btrfs_end_transaction(trans, extent_root);
|
|
|
|
kfree(new_extents);
|
|
|
|
kfree(ref_path);
|
|
|
|
return ret;
|
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#endif
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
2008-04-28 19:29:52 +00:00
|
|
|
static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
|
|
|
|
{
|
|
|
|
u64 num_devices;
|
|
|
|
u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
|
|
|
|
|
2010-12-13 19:56:23 +00:00
|
|
|
/*
|
|
|
|
* we add in the count of missing devices because we want
|
|
|
|
* to make sure that any RAID levels on a degraded FS
|
|
|
|
* continue to be honored.
|
|
|
|
*/
|
|
|
|
num_devices = root->fs_info->fs_devices->rw_devices +
|
|
|
|
root->fs_info->fs_devices->missing_devices;
|
|
|
|
|
2008-04-28 19:29:52 +00:00
|
|
|
if (num_devices == 1) {
|
|
|
|
stripped |= BTRFS_BLOCK_GROUP_DUP;
|
|
|
|
stripped = flags & ~stripped;
|
|
|
|
|
|
|
|
/* turn raid0 into single device chunks */
|
|
|
|
if (flags & BTRFS_BLOCK_GROUP_RAID0)
|
|
|
|
return stripped;
|
|
|
|
|
|
|
|
/* turn mirroring into duplication */
|
|
|
|
if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID10))
|
|
|
|
return stripped | BTRFS_BLOCK_GROUP_DUP;
|
|
|
|
return flags;
|
|
|
|
} else {
|
|
|
|
/* they already had raid on here, just return */
|
|
|
|
if (flags & stripped)
|
|
|
|
return flags;
|
|
|
|
|
|
|
|
stripped |= BTRFS_BLOCK_GROUP_DUP;
|
|
|
|
stripped = flags & ~stripped;
|
|
|
|
|
|
|
|
/* switch duplicated blocks with raid1 */
|
|
|
|
if (flags & BTRFS_BLOCK_GROUP_DUP)
|
|
|
|
return stripped | BTRFS_BLOCK_GROUP_RAID1;
|
|
|
|
|
|
|
|
/* turn single device chunks into raid0 */
|
|
|
|
return stripped | BTRFS_BLOCK_GROUP_RAID0;
|
|
|
|
}
|
|
|
|
return flags;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
static int set_block_group_ro(struct btrfs_block_group_cache *cache)
|
2008-05-24 18:04:53 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
struct btrfs_space_info *sinfo = cache->space_info;
|
|
|
|
u64 num_bytes;
|
|
|
|
int ret = -ENOSPC;
|
2008-05-24 18:04:53 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
if (cache->ro)
|
|
|
|
return 0;
|
2008-07-23 03:06:41 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
spin_lock(&sinfo->lock);
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
num_bytes = cache->key.offset - cache->reserved - cache->pinned -
|
|
|
|
cache->bytes_super - btrfs_block_group_used(&cache->item);
|
|
|
|
|
|
|
|
if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
|
|
|
|
sinfo->bytes_may_use + sinfo->bytes_readonly +
|
2010-12-24 11:41:52 +00:00
|
|
|
cache->reserved_pinned + num_bytes <= sinfo->total_bytes) {
|
2010-05-16 14:46:25 +00:00
|
|
|
sinfo->bytes_readonly += num_bytes;
|
|
|
|
sinfo->bytes_reserved += cache->reserved_pinned;
|
|
|
|
cache->reserved_pinned = 0;
|
|
|
|
cache->ro = 1;
|
|
|
|
ret = 0;
|
|
|
|
}
|
2010-12-24 11:41:52 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
spin_unlock(&sinfo->lock);
|
|
|
|
return ret;
|
|
|
|
}
|
2008-07-08 18:19:17 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
int btrfs_set_block_group_ro(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
2008-07-23 03:06:41 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
{
|
|
|
|
struct btrfs_trans_handle *trans;
|
|
|
|
u64 alloc_flags;
|
|
|
|
int ret;
|
2008-07-08 18:19:17 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
BUG_ON(cache->ro);
|
2008-05-24 18:04:53 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
trans = btrfs_join_transaction(root, 1);
|
|
|
|
BUG_ON(IS_ERR(trans));
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
alloc_flags = update_block_group_flags(root, cache->flags);
|
|
|
|
if (alloc_flags != cache->flags)
|
|
|
|
do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
ret = set_block_group_ro(cache);
|
|
|
|
if (!ret)
|
|
|
|
goto out;
|
|
|
|
alloc_flags = get_alloc_profile(root, cache->space_info->flags);
|
|
|
|
ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
ret = set_block_group_ro(cache);
|
|
|
|
out:
|
|
|
|
btrfs_end_transaction(trans, root);
|
|
|
|
return ret;
|
|
|
|
}
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
btrfs: fix wrong free space information of btrfs
When we store data by raid profile in btrfs with two or more different size
disks, df command shows there is some free space in the filesystem, but the
user can not write any data in fact, df command shows the wrong free space
information of btrfs.
# mkfs.btrfs -d raid1 /dev/sda9 /dev/sda10
# btrfs-show
Label: none uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
Total devices 2 FS bytes used 28.00KB
devid 1 size 5.01GB used 2.03GB path /dev/sda9
devid 2 size 10.00GB used 2.01GB path /dev/sda10
# btrfs device scan /dev/sda9 /dev/sda10
# mount /dev/sda9 /mnt
# dd if=/dev/zero of=tmpfile0 bs=4K count=9999999999
(fill the filesystem)
# sync
# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda9 btrfs 17G 8.6G 5.4G 62% /mnt
# btrfs-show
Label: none uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
Total devices 2 FS bytes used 3.99GB
devid 1 size 5.01GB used 5.01GB path /dev/sda9
devid 2 size 10.00GB used 4.99GB path /dev/sda10
It is because btrfs cannot allocate chunks when one of the pairing disks has
no space, the free space on the other disks can not be used for ever, and should
be subtracted from the total space, but btrfs doesn't subtract this space from
the total. It is strange to the user.
This patch fixes it by calcing the free space that can be used to allocate
chunks.
Implementation:
1. get all the devices free space, and align them by stripe length.
2. sort the devices by the free space.
3. check the free space of the devices,
3.1. if it is not zero, and then check the number of the devices that has
more free space than this device,
if the number of the devices is beyond the min stripe number, the free
space can be used, and add into total free space.
if the number of the devices is below the min stripe number, we can not
use the free space, the check ends.
3.2. if the free space is zero, check the next devices, goto 3.1
This implementation is just likely fake chunk allocation.
After appling this patch, df can show correct space information:
# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda9 btrfs 17G 8.6G 0 100% /mnt
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-01-05 10:07:31 +00:00
|
|
|
/*
|
|
|
|
* helper to account the unused space of all the readonly block group in the
|
|
|
|
* list. takes mirrors into account.
|
|
|
|
*/
|
|
|
|
static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
|
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
|
|
|
u64 free_bytes = 0;
|
|
|
|
int factor;
|
|
|
|
|
|
|
|
list_for_each_entry(block_group, groups_list, list) {
|
|
|
|
spin_lock(&block_group->lock);
|
|
|
|
|
|
|
|
if (!block_group->ro) {
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID10 |
|
|
|
|
BTRFS_BLOCK_GROUP_DUP))
|
|
|
|
factor = 2;
|
|
|
|
else
|
|
|
|
factor = 1;
|
|
|
|
|
|
|
|
free_bytes += (block_group->key.offset -
|
|
|
|
btrfs_block_group_used(&block_group->item)) *
|
|
|
|
factor;
|
|
|
|
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
return free_bytes;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* helper to account the unused space of all the readonly block group in the
|
|
|
|
* space_info. takes mirrors into account.
|
|
|
|
*/
|
|
|
|
u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
u64 free_bytes = 0;
|
|
|
|
|
|
|
|
spin_lock(&sinfo->lock);
|
|
|
|
|
|
|
|
for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
|
|
|
|
if (!list_empty(&sinfo->block_groups[i]))
|
|
|
|
free_bytes += __btrfs_get_ro_block_group_free_space(
|
|
|
|
&sinfo->block_groups[i]);
|
|
|
|
|
|
|
|
spin_unlock(&sinfo->lock);
|
|
|
|
|
|
|
|
return free_bytes;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
int btrfs_set_block_group_rw(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
{
|
2010-05-16 14:46:25 +00:00
|
|
|
struct btrfs_space_info *sinfo = cache->space_info;
|
|
|
|
u64 num_bytes;
|
|
|
|
|
|
|
|
BUG_ON(!cache->ro);
|
|
|
|
|
|
|
|
spin_lock(&sinfo->lock);
|
|
|
|
spin_lock(&cache->lock);
|
|
|
|
num_bytes = cache->key.offset - cache->reserved - cache->pinned -
|
|
|
|
cache->bytes_super - btrfs_block_group_used(&cache->item);
|
|
|
|
sinfo->bytes_readonly -= num_bytes;
|
|
|
|
cache->ro = 0;
|
|
|
|
spin_unlock(&cache->lock);
|
|
|
|
spin_unlock(&sinfo->lock);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
/*
|
|
|
|
* checks to see if its even possible to relocate this block group.
|
|
|
|
*
|
|
|
|
* @return - -1 if it's not a good idea to relocate this block group, 0 if its
|
|
|
|
* ok to go ahead and try.
|
|
|
|
*/
|
|
|
|
int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
{
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_block_group_cache *block_group;
|
|
|
|
struct btrfs_space_info *space_info;
|
|
|
|
struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
|
|
|
|
struct btrfs_device *device;
|
|
|
|
int full = 0;
|
|
|
|
int ret = 0;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
/* odd, couldn't find the block group, leave it alone */
|
|
|
|
if (!block_group)
|
|
|
|
return -1;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
/* no bytes used, we're good */
|
|
|
|
if (!btrfs_block_group_used(&block_group->item))
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
goto out;
|
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
space_info = block_group->space_info;
|
|
|
|
spin_lock(&space_info->lock);
|
2008-12-12 15:03:38 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
full = space_info->full;
|
2008-12-12 15:03:38 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
/*
|
|
|
|
* if this is the last block group we have in this space, we can't
|
2009-09-22 18:48:44 +00:00
|
|
|
* relocate it unless we're able to allocate a new chunk below.
|
|
|
|
*
|
|
|
|
* Otherwise, we need to make sure we have room in the space to handle
|
|
|
|
* all of the extents from this block group. If we can, we're good
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
*/
|
2009-09-22 18:48:44 +00:00
|
|
|
if ((space_info->total_bytes != block_group->key.offset) &&
|
|
|
|
(space_info->bytes_used + space_info->bytes_reserved +
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
space_info->bytes_pinned + space_info->bytes_readonly +
|
|
|
|
btrfs_block_group_used(&block_group->item) <
|
2009-09-22 18:48:44 +00:00
|
|
|
space_info->total_bytes)) {
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
spin_unlock(&space_info->lock);
|
|
|
|
goto out;
|
2008-12-12 15:03:38 +00:00
|
|
|
}
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
spin_unlock(&space_info->lock);
|
2008-08-05 03:17:27 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
/*
|
|
|
|
* ok we don't have enough space, but maybe we have free space on our
|
|
|
|
* devices to allocate new chunks for relocation, so loop through our
|
|
|
|
* alloc devices and guess if we have enough space. However, if we
|
|
|
|
* were marked as full, then we know there aren't enough chunks, and we
|
|
|
|
* can just return.
|
|
|
|
*/
|
|
|
|
ret = -1;
|
|
|
|
if (full)
|
|
|
|
goto out;
|
2008-08-05 03:17:27 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
mutex_lock(&root->fs_info->chunk_mutex);
|
|
|
|
list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
|
|
|
|
u64 min_free = btrfs_block_group_used(&block_group->item);
|
2011-01-05 10:07:26 +00:00
|
|
|
u64 dev_offset;
|
2009-03-13 14:10:06 +00:00
|
|
|
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
/*
|
|
|
|
* check to make sure we can actually find a chunk with enough
|
|
|
|
* space to fit our block group in.
|
|
|
|
*/
|
|
|
|
if (device->total_bytes > device->bytes_used + min_free) {
|
|
|
|
ret = find_free_dev_extent(NULL, device, min_free,
|
2011-01-05 10:07:26 +00:00
|
|
|
&dev_offset, NULL);
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
if (!ret)
|
2008-01-03 19:14:39 +00:00
|
|
|
break;
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
ret = -1;
|
2008-01-04 21:47:16 +00:00
|
|
|
}
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
mutex_unlock(&root->fs_info->chunk_mutex);
|
2007-12-21 21:27:24 +00:00
|
|
|
out:
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
2007-12-21 21:27:24 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2008-12-02 14:54:17 +00:00
|
|
|
static int find_first_block_group(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, struct btrfs_key *key)
|
2008-03-24 19:01:56 +00:00
|
|
|
{
|
2008-06-25 20:01:30 +00:00
|
|
|
int ret = 0;
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_key found_key;
|
|
|
|
struct extent_buffer *leaf;
|
|
|
|
int slot;
|
2007-12-21 21:27:24 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
|
|
|
|
if (ret < 0)
|
2008-06-25 20:01:30 +00:00
|
|
|
goto out;
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (1) {
|
2008-03-24 19:01:56 +00:00
|
|
|
slot = path->slots[0];
|
2007-12-21 21:27:24 +00:00
|
|
|
leaf = path->nodes[0];
|
2008-03-24 19:01:56 +00:00
|
|
|
if (slot >= btrfs_header_nritems(leaf)) {
|
|
|
|
ret = btrfs_next_leaf(root, path);
|
|
|
|
if (ret == 0)
|
|
|
|
continue;
|
|
|
|
if (ret < 0)
|
2008-06-25 20:01:30 +00:00
|
|
|
goto out;
|
2008-03-24 19:01:56 +00:00
|
|
|
break;
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
2008-03-24 19:01:56 +00:00
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, slot);
|
2007-12-21 21:27:24 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
if (found_key.objectid >= key->objectid &&
|
2008-06-25 20:01:30 +00:00
|
|
|
found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
2008-03-24 19:01:56 +00:00
|
|
|
path->slots[0]++;
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
2008-06-25 20:01:30 +00:00
|
|
|
out:
|
2008-03-24 19:01:56 +00:00
|
|
|
return ret;
|
2007-12-21 21:27:24 +00:00
|
|
|
}
|
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
|
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
|
|
|
u64 last = 0;
|
|
|
|
|
|
|
|
while (1) {
|
|
|
|
struct inode *inode;
|
|
|
|
|
|
|
|
block_group = btrfs_lookup_first_block_group(info, last);
|
|
|
|
while (block_group) {
|
|
|
|
spin_lock(&block_group->lock);
|
|
|
|
if (block_group->iref)
|
|
|
|
break;
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
block_group = next_block_group(info->tree_root,
|
|
|
|
block_group);
|
|
|
|
}
|
|
|
|
if (!block_group) {
|
|
|
|
if (last == 0)
|
|
|
|
break;
|
|
|
|
last = 0;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
inode = block_group->inode;
|
|
|
|
block_group->iref = 0;
|
|
|
|
block_group->inode = NULL;
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
iput(inode);
|
|
|
|
last = block_group->key.objectid + block_group->key.offset;
|
|
|
|
btrfs_put_block_group(block_group);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int btrfs_free_block_groups(struct btrfs_fs_info *info)
|
|
|
|
{
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
2009-03-10 16:39:20 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control *caching_ctl;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct rb_node *n;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
down_write(&info->extent_commit_sem);
|
|
|
|
while (!list_empty(&info->caching_block_groups)) {
|
|
|
|
caching_ctl = list_entry(info->caching_block_groups.next,
|
|
|
|
struct btrfs_caching_control, list);
|
|
|
|
list_del(&caching_ctl->list);
|
|
|
|
put_caching_control(caching_ctl);
|
|
|
|
}
|
|
|
|
up_write(&info->extent_commit_sem);
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
spin_lock(&info->block_group_cache_lock);
|
|
|
|
while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
|
|
|
|
block_group = rb_entry(n, struct btrfs_block_group_cache,
|
|
|
|
cache_node);
|
|
|
|
rb_erase(&block_group->cache_node,
|
|
|
|
&info->block_group_cache_tree);
|
2008-10-30 18:25:28 +00:00
|
|
|
spin_unlock(&info->block_group_cache_lock);
|
|
|
|
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
down_write(&block_group->space_info->groups_sem);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
list_del(&block_group->list);
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
up_write(&block_group->space_info->groups_sem);
|
2008-12-11 21:30:39 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (block_group->cached == BTRFS_CACHE_STARTED)
|
2009-09-11 20:11:19 +00:00
|
|
|
wait_block_group_cache_done(block_group);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
|
|
|
btrfs_remove_free_space_cache(block_group);
|
2009-11-13 20:12:59 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
2008-10-30 18:25:28 +00:00
|
|
|
|
|
|
|
spin_lock(&info->block_group_cache_lock);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
}
|
|
|
|
spin_unlock(&info->block_group_cache_lock);
|
2009-03-10 16:39:20 +00:00
|
|
|
|
|
|
|
/* now that all the block groups are freed, go through and
|
|
|
|
* free all the space_info structs. This is only called during
|
|
|
|
* the final stages of unmount, and so we know nobody is
|
|
|
|
* using them. We call synchronize_rcu() once before we start,
|
|
|
|
* just to be on the safe side.
|
|
|
|
*/
|
|
|
|
synchronize_rcu();
|
|
|
|
|
2010-05-16 14:49:58 +00:00
|
|
|
release_global_block_rsv(info);
|
|
|
|
|
2009-03-10 16:39:20 +00:00
|
|
|
while(!list_empty(&info->space_info)) {
|
|
|
|
space_info = list_entry(info->space_info.next,
|
|
|
|
struct btrfs_space_info,
|
|
|
|
list);
|
2010-05-16 14:46:25 +00:00
|
|
|
if (space_info->bytes_pinned > 0 ||
|
|
|
|
space_info->bytes_reserved > 0) {
|
|
|
|
WARN_ON(1);
|
|
|
|
dump_space_info(space_info, 0, 0);
|
|
|
|
}
|
2009-03-10 16:39:20 +00:00
|
|
|
list_del(&space_info->list);
|
|
|
|
kfree(space_info);
|
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
static void __link_block_group(struct btrfs_space_info *space_info,
|
|
|
|
struct btrfs_block_group_cache *cache)
|
|
|
|
{
|
|
|
|
int index = get_block_group_index(cache);
|
|
|
|
|
|
|
|
down_write(&space_info->groups_sem);
|
|
|
|
list_add_tail(&cache->list, &space_info->block_groups[index]);
|
|
|
|
up_write(&space_info->groups_sem);
|
|
|
|
}
|
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
int btrfs_read_block_groups(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_path *path;
|
|
|
|
int ret;
|
|
|
|
struct btrfs_block_group_cache *cache;
|
2007-05-06 14:15:01 +00:00
|
|
|
struct btrfs_fs_info *info = root->fs_info;
|
2008-03-24 19:01:59 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
2007-04-26 20:46:15 +00:00
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_key found_key;
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *leaf;
|
2010-06-21 18:48:16 +00:00
|
|
|
int need_clear = 0;
|
|
|
|
u64 cache_gen;
|
2007-10-15 20:15:19 +00:00
|
|
|
|
2007-05-06 14:15:01 +00:00
|
|
|
root = info->extent_root;
|
2007-04-26 20:46:15 +00:00
|
|
|
key.objectid = 0;
|
2008-03-24 19:01:56 +00:00
|
|
|
key.offset = 0;
|
2007-04-26 20:46:15 +00:00
|
|
|
btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
|
|
|
|
if (cache_gen != 0 &&
|
|
|
|
btrfs_super_generation(&root->fs_info->super_copy) != cache_gen)
|
|
|
|
need_clear = 1;
|
2010-09-21 18:21:34 +00:00
|
|
|
if (btrfs_test_opt(root, CLEAR_CACHE))
|
|
|
|
need_clear = 1;
|
2010-10-28 20:55:47 +00:00
|
|
|
if (!btrfs_test_opt(root, SPACE_CACHE) && cache_gen)
|
|
|
|
printk(KERN_INFO "btrfs: disk space caching is enabled\n");
|
2010-06-21 18:48:16 +00:00
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
while (1) {
|
2008-03-24 19:01:56 +00:00
|
|
|
ret = find_first_block_group(root, path, &key);
|
2010-05-16 14:46:24 +00:00
|
|
|
if (ret > 0)
|
|
|
|
break;
|
2008-03-24 19:01:56 +00:00
|
|
|
if (ret != 0)
|
|
|
|
goto error;
|
2007-10-15 20:14:19 +00:00
|
|
|
leaf = path->nodes[0];
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
2008-04-25 20:53:30 +00:00
|
|
|
cache = kzalloc(sizeof(*cache), GFP_NOFS);
|
2007-04-26 20:46:15 +00:00
|
|
|
if (!cache) {
|
2008-03-24 19:01:56 +00:00
|
|
|
ret = -ENOMEM;
|
2010-05-16 14:46:25 +00:00
|
|
|
goto error;
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
2007-05-08 00:03:49 +00:00
|
|
|
|
2008-12-11 21:30:39 +00:00
|
|
|
atomic_set(&cache->count, 1);
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_lock_init(&cache->lock);
|
2009-04-03 14:14:18 +00:00
|
|
|
spin_lock_init(&cache->tree_lock);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->fs_info = info;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
INIT_LIST_HEAD(&cache->list);
|
2009-04-03 13:47:43 +00:00
|
|
|
INIT_LIST_HEAD(&cache->cluster_list);
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
if (need_clear)
|
|
|
|
cache->disk_cache_state = BTRFS_DC_CLEAR;
|
|
|
|
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
/*
|
|
|
|
* we only want to have 32k of ram per block group for keeping
|
|
|
|
* track of free space, and if we pass 1/2 of that we want to
|
|
|
|
* start converting things over to using bitmaps
|
|
|
|
*/
|
|
|
|
cache->extents_thresh = ((1024 * 32) / 2) /
|
|
|
|
sizeof(struct btrfs_free_space);
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
read_extent_buffer(leaf, &cache->item,
|
|
|
|
btrfs_item_ptr_offset(leaf, path->slots[0]),
|
|
|
|
sizeof(cache->item));
|
2007-04-26 20:46:15 +00:00
|
|
|
memcpy(&cache->key, &found_key, sizeof(found_key));
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
key.objectid = found_key.objectid + found_key.offset;
|
|
|
|
btrfs_release_path(root, path);
|
2008-03-24 19:01:56 +00:00
|
|
|
cache->flags = btrfs_block_group_flags(&cache->item);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->sectorsize = root->sectorsize;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* check for two cases, either we are full, and therefore
|
|
|
|
* don't need to bother with the caching work since we won't
|
|
|
|
* find any space, or we are empty, and we can just add all
|
|
|
|
* the space in and be done with it. This saves us _alot_ of
|
|
|
|
* time, particularly in the full case.
|
|
|
|
*/
|
|
|
|
if (found_key.offset == btrfs_block_group_used(&cache->item)) {
|
2009-09-11 20:11:20 +00:00
|
|
|
exclude_super_stripes(root, cache);
|
2009-09-11 20:11:19 +00:00
|
|
|
cache->last_byte_to_unpin = (u64)-1;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->cached = BTRFS_CACHE_FINISHED;
|
2009-09-11 20:11:20 +00:00
|
|
|
free_excluded_extents(root, cache);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
} else if (btrfs_block_group_used(&cache->item) == 0) {
|
2009-09-11 20:11:19 +00:00
|
|
|
exclude_super_stripes(root, cache);
|
|
|
|
cache->last_byte_to_unpin = (u64)-1;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->cached = BTRFS_CACHE_FINISHED;
|
|
|
|
add_new_free_space(cache, root->fs_info,
|
|
|
|
found_key.objectid,
|
|
|
|
found_key.objectid +
|
|
|
|
found_key.offset);
|
2009-09-11 20:11:19 +00:00
|
|
|
free_excluded_extents(root, cache);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
}
|
2007-10-15 20:15:19 +00:00
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
ret = update_space_info(info, cache->flags, found_key.offset,
|
|
|
|
btrfs_block_group_used(&cache->item),
|
|
|
|
&space_info);
|
|
|
|
BUG_ON(ret);
|
|
|
|
cache->space_info = space_info;
|
2009-09-11 20:11:20 +00:00
|
|
|
spin_lock(&cache->space_info->lock);
|
2010-05-16 14:46:25 +00:00
|
|
|
cache->space_info->bytes_readonly += cache->bytes_super;
|
2009-09-11 20:11:20 +00:00
|
|
|
spin_unlock(&cache->space_info->lock);
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
__link_block_group(space_info, cache);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
|
|
|
ret = btrfs_add_block_group_cache(root->fs_info, cache);
|
|
|
|
BUG_ON(ret);
|
2008-09-30 23:24:06 +00:00
|
|
|
|
|
|
|
set_avail_alloc_bits(root->fs_info, cache->flags);
|
2008-11-18 02:11:30 +00:00
|
|
|
if (btrfs_chunk_readonly(root, cache->key.objectid))
|
2010-05-16 14:46:25 +00:00
|
|
|
set_block_group_ro(cache);
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
2010-05-16 14:46:24 +00:00
|
|
|
|
|
|
|
list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
|
|
|
|
if (!(get_alloc_profile(root, space_info->flags) &
|
|
|
|
(BTRFS_BLOCK_GROUP_RAID10 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_DUP)))
|
|
|
|
continue;
|
|
|
|
/*
|
|
|
|
* avoid allocating from un-mirrored block group if there are
|
|
|
|
* mirrored block groups.
|
|
|
|
*/
|
|
|
|
list_for_each_entry(cache, &space_info->block_groups[3], list)
|
2010-05-16 14:46:25 +00:00
|
|
|
set_block_group_ro(cache);
|
2010-05-16 14:46:24 +00:00
|
|
|
list_for_each_entry(cache, &space_info->block_groups[4], list)
|
2010-05-16 14:46:25 +00:00
|
|
|
set_block_group_ro(cache);
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
2010-05-16 14:46:25 +00:00
|
|
|
|
|
|
|
init_global_block_rsv(info);
|
2008-03-24 19:01:56 +00:00
|
|
|
ret = 0;
|
|
|
|
error:
|
2007-04-26 20:46:15 +00:00
|
|
|
btrfs_free_path(path);
|
2008-03-24 19:01:56 +00:00
|
|
|
return ret;
|
2007-04-26 20:46:15 +00:00
|
|
|
}
|
2008-03-24 19:01:59 +00:00
|
|
|
|
|
|
|
int btrfs_make_block_group(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 bytes_used,
|
2008-04-15 19:41:47 +00:00
|
|
|
u64 type, u64 chunk_objectid, u64 chunk_offset,
|
2008-03-24 19:01:59 +00:00
|
|
|
u64 size)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
struct btrfs_root *extent_root;
|
|
|
|
struct btrfs_block_group_cache *cache;
|
|
|
|
|
|
|
|
extent_root = root->fs_info->extent_root;
|
|
|
|
|
2009-03-24 14:24:20 +00:00
|
|
|
root->fs_info->last_trans_log_full_commit = trans->transid;
|
2008-09-05 20:13:11 +00:00
|
|
|
|
2008-04-25 20:53:30 +00:00
|
|
|
cache = kzalloc(sizeof(*cache), GFP_NOFS);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
if (!cache)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2008-04-15 19:41:47 +00:00
|
|
|
cache->key.objectid = chunk_offset;
|
2008-03-24 19:01:59 +00:00
|
|
|
cache->key.offset = size;
|
2008-12-11 21:30:39 +00:00
|
|
|
cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->sectorsize = root->sectorsize;
|
2010-06-21 18:48:16 +00:00
|
|
|
cache->fs_info = root->fs_info;
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* we only want to have 32k of ram per block group for keeping track
|
|
|
|
* of free space, and if we pass 1/2 of that we want to start
|
|
|
|
* converting things over to using bitmaps
|
|
|
|
*/
|
|
|
|
cache->extents_thresh = ((1024 * 32) / 2) /
|
|
|
|
sizeof(struct btrfs_free_space);
|
2008-12-11 21:30:39 +00:00
|
|
|
atomic_set(&cache->count, 1);
|
2008-07-23 03:06:41 +00:00
|
|
|
spin_lock_init(&cache->lock);
|
2009-04-03 14:14:18 +00:00
|
|
|
spin_lock_init(&cache->tree_lock);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
INIT_LIST_HEAD(&cache->list);
|
2009-04-03 13:47:43 +00:00
|
|
|
INIT_LIST_HEAD(&cache->cluster_list);
|
2008-05-24 18:04:53 +00:00
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
btrfs_set_block_group_used(&cache->item, bytes_used);
|
|
|
|
btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
|
|
|
|
cache->flags = type;
|
|
|
|
btrfs_set_block_group_flags(&cache->item, type);
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
cache->last_byte_to_unpin = (u64)-1;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
cache->cached = BTRFS_CACHE_FINISHED;
|
2009-09-11 20:11:19 +00:00
|
|
|
exclude_super_stripes(root, cache);
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
add_new_free_space(cache, root->fs_info, chunk_offset,
|
|
|
|
chunk_offset + size);
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
free_excluded_extents(root, cache);
|
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
|
|
|
|
&cache->space_info);
|
|
|
|
BUG_ON(ret);
|
2009-09-11 20:11:20 +00:00
|
|
|
|
|
|
|
spin_lock(&cache->space_info->lock);
|
2010-05-16 14:46:25 +00:00
|
|
|
cache->space_info->bytes_readonly += cache->bytes_super;
|
2009-09-11 20:11:20 +00:00
|
|
|
spin_unlock(&cache->space_info->lock);
|
|
|
|
|
2010-05-16 14:46:24 +00:00
|
|
|
__link_block_group(cache->space_info, cache);
|
2008-03-24 19:01:59 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
ret = btrfs_add_block_group_cache(root->fs_info, cache);
|
|
|
|
BUG_ON(ret);
|
2008-07-23 03:06:41 +00:00
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
|
|
|
|
sizeof(cache->item));
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
2008-04-04 19:40:00 +00:00
|
|
|
set_avail_alloc_bits(extent_root->fs_info, type);
|
2008-06-25 20:01:30 +00:00
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
return 0;
|
|
|
|
}
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 group_start)
|
|
|
|
{
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
2009-06-04 19:34:51 +00:00
|
|
|
struct btrfs_free_cluster *cluster;
|
2010-06-21 18:48:16 +00:00
|
|
|
struct btrfs_root *tree_root = root->fs_info->tree_root;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_key key;
|
2010-06-21 18:48:16 +00:00
|
|
|
struct inode *inode;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int ret;
|
2010-10-14 18:52:27 +00:00
|
|
|
int factor;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
root = root->fs_info->extent_root;
|
|
|
|
|
|
|
|
block_group = btrfs_lookup_block_group(root->fs_info, group_start);
|
|
|
|
BUG_ON(!block_group);
|
2008-11-12 19:34:12 +00:00
|
|
|
BUG_ON(!block_group->ro);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
memcpy(&key, &block_group->key, sizeof(key));
|
2010-10-14 18:52:27 +00:00
|
|
|
if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID1 |
|
|
|
|
BTRFS_BLOCK_GROUP_RAID10))
|
|
|
|
factor = 2;
|
|
|
|
else
|
|
|
|
factor = 1;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
2009-06-04 19:34:51 +00:00
|
|
|
/* make sure this block group isn't part of an allocation cluster */
|
|
|
|
cluster = &root->fs_info->data_alloc_cluster;
|
|
|
|
spin_lock(&cluster->refill_lock);
|
|
|
|
btrfs_return_cluster_to_free_space(block_group, cluster);
|
|
|
|
spin_unlock(&cluster->refill_lock);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* make sure this block group isn't part of a metadata
|
|
|
|
* allocation cluster
|
|
|
|
*/
|
|
|
|
cluster = &root->fs_info->meta_alloc_cluster;
|
|
|
|
spin_lock(&cluster->refill_lock);
|
|
|
|
btrfs_return_cluster_to_free_space(block_group, cluster);
|
|
|
|
spin_unlock(&cluster->refill_lock);
|
|
|
|
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
path = btrfs_alloc_path();
|
|
|
|
BUG_ON(!path);
|
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
inode = lookup_free_space_inode(root, block_group, path);
|
|
|
|
if (!IS_ERR(inode)) {
|
|
|
|
btrfs_orphan_add(trans, inode);
|
|
|
|
clear_nlink(inode);
|
|
|
|
/* One for the block groups ref */
|
|
|
|
spin_lock(&block_group->lock);
|
|
|
|
if (block_group->iref) {
|
|
|
|
block_group->iref = 0;
|
|
|
|
block_group->inode = NULL;
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
iput(inode);
|
|
|
|
} else {
|
|
|
|
spin_unlock(&block_group->lock);
|
|
|
|
}
|
|
|
|
/* One for our lookup ref */
|
|
|
|
iput(inode);
|
|
|
|
}
|
|
|
|
|
|
|
|
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
|
|
|
|
key.offset = block_group->key.objectid;
|
|
|
|
key.type = 0;
|
|
|
|
|
|
|
|
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
if (ret > 0)
|
|
|
|
btrfs_release_path(tree_root, path);
|
|
|
|
if (ret == 0) {
|
|
|
|
ret = btrfs_del_item(trans, tree_root, path);
|
|
|
|
if (ret)
|
|
|
|
goto out;
|
|
|
|
btrfs_release_path(tree_root, path);
|
|
|
|
}
|
|
|
|
|
2009-01-21 15:49:16 +00:00
|
|
|
spin_lock(&root->fs_info->block_group_cache_lock);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
rb_erase(&block_group->cache_node,
|
|
|
|
&root->fs_info->block_group_cache_tree);
|
2009-01-21 15:49:16 +00:00
|
|
|
spin_unlock(&root->fs_info->block_group_cache_lock);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
down_write(&block_group->space_info->groups_sem);
|
2009-06-04 19:34:51 +00:00
|
|
|
/*
|
|
|
|
* we must use list_del_init so people can check to see if they
|
|
|
|
* are still on the list after taking the semaphore
|
|
|
|
*/
|
|
|
|
list_del_init(&block_group->list);
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
up_write(&block_group->space_info->groups_sem);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
if (block_group->cached == BTRFS_CACHE_STARTED)
|
2009-09-11 20:11:19 +00:00
|
|
|
wait_block_group_cache_done(block_group);
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
|
|
|
btrfs_remove_free_space_cache(block_group);
|
|
|
|
|
2008-11-12 19:34:12 +00:00
|
|
|
spin_lock(&block_group->space_info->lock);
|
|
|
|
block_group->space_info->total_bytes -= block_group->key.offset;
|
|
|
|
block_group->space_info->bytes_readonly -= block_group->key.offset;
|
2010-10-14 18:52:27 +00:00
|
|
|
block_group->space_info->disk_total -= block_group->key.offset * factor;
|
2008-11-12 19:34:12 +00:00
|
|
|
spin_unlock(&block_group->space_info->lock);
|
2009-07-24 20:30:55 +00:00
|
|
|
|
2010-06-21 18:48:16 +00:00
|
|
|
memcpy(&key, &block_group->key, sizeof(key));
|
|
|
|
|
2009-07-24 20:30:55 +00:00
|
|
|
btrfs_clear_space_info_full(root->fs_info);
|
2008-11-12 19:34:12 +00:00
|
|
|
|
2009-04-03 13:47:43 +00:00
|
|
|
btrfs_put_block_group(block_group);
|
|
|
|
btrfs_put_block_group(block_group);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
|
|
|
|
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
|
|
|
|
if (ret > 0)
|
|
|
|
ret = -EIO;
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ret = btrfs_del_item(trans, root, path);
|
|
|
|
out:
|
|
|
|
btrfs_free_path(path);
|
|
|
|
return ret;
|
|
|
|
}
|
2011-01-06 11:30:25 +00:00
|
|
|
|
|
|
|
int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
|
|
|
|
{
|
|
|
|
return unpin_extent_range(root, start, end);
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
|
|
|
|
u64 num_bytes)
|
|
|
|
{
|
|
|
|
return btrfs_discard_extent(root, bytenr, num_bytes);
|
|
|
|
}
|