2018-04-03 17:16:55 +00:00
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/* SPDX-License-Identifier: GPL-2.0 */
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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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2018-04-03 17:16:55 +00:00
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#ifndef BTRFS_CTREE_H
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#define BTRFS_CTREE_H
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2007-02-02 14:18:22 +00:00
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2011-09-21 19:05:58 +00:00
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#include <linux/pagemap.h>
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2024-01-27 03:31:30 +00:00
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#include <linux/spinlock.h>
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#include <linux/rbtree.h>
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#include <linux/mutex.h>
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#include <linux/wait.h>
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#include <linux/list.h>
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#include <linux/atomic.h>
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#include <linux/xarray.h>
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#include <linux/refcount.h>
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#include <uapi/linux/btrfs_tree.h>
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2020-01-30 12:59:44 +00:00
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#include "locking.h"
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2022-10-24 18:46:52 +00:00
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#include "fs.h"
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2023-09-27 11:09:27 +00:00
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#include "accessors.h"
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2024-01-27 03:31:30 +00:00
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#include "extent-io-tree.h"
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2007-03-22 16:13:20 +00:00
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2024-01-27 03:31:30 +00:00
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struct extent_buffer;
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struct btrfs_block_rsv;
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2007-03-16 20:20:31 +00:00
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struct btrfs_trans_handle;
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2019-10-29 18:20:18 +00:00
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struct btrfs_block_group;
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2007-03-16 20:20:31 +00:00
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2021-03-31 10:56:21 +00:00
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/* Read ahead values for struct btrfs_path.reada */
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enum {
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READA_NONE,
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READA_BACK,
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READA_FORWARD,
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/*
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* Similar to READA_FORWARD but unlike it:
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*
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* 1) It will trigger readahead even for leaves that are not close to
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* each other on disk;
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* 2) It also triggers readahead for nodes;
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* 3) During a search, even when a node or leaf is already in memory, it
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* will still trigger readahead for other nodes and leaves that follow
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* it.
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*
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* This is meant to be used only when we know we are iterating over the
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* entire tree or a very large part of it.
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*/
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READA_FORWARD_ALWAYS,
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};
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2007-02-26 15:40:21 +00:00
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/*
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2007-03-13 14:46:10 +00:00
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* btrfs_paths remember the path taken from the root down to the leaf.
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* level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
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2007-02-26 15:40:21 +00:00
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* to any other levels that are present.
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*
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* The slots array records the index of the item or block pointer
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* used while walking the tree.
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*/
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2007-03-13 14:46:10 +00:00
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struct btrfs_path {
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2007-10-15 20:14:19 +00:00
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struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
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2007-03-13 14:46:10 +00:00
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int slots[BTRFS_MAX_LEVEL];
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2008-06-25 20:01:30 +00:00
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/* if there is real range locking, this locks field will change */
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2015-11-27 15:31:45 +00:00
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u8 locks[BTRFS_MAX_LEVEL];
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2015-11-27 15:31:38 +00:00
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u8 reada;
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2008-06-25 20:01:30 +00:00
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/* keep some upper locks as we walk down */
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2015-11-27 15:31:42 +00:00
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u8 lowest_level;
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2008-12-10 14:10:46 +00:00
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/*
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* set by btrfs_split_item, tells search_slot to keep all locks
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* and to force calls to keep space in the nodes
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*/
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2009-03-13 15:00:37 +00:00
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unsigned int search_for_split:1;
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unsigned int keep_locks:1;
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unsigned int skip_locking:1;
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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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unsigned int search_commit_root:1;
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2014-03-28 21:16:01 +00:00
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unsigned int need_commit_sem:1;
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2014-11-09 08:38:39 +00:00
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unsigned int skip_release_on_error:1;
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btrfs: correctly calculate item size used when item key collision happens
Item key collision is allowed for some item types, like dir item and
inode refs, but the overall item size is limited by the nodesize.
item size(ins_len) passed from btrfs_insert_empty_items to
btrfs_search_slot already contains size of btrfs_item.
When btrfs_search_slot reaches leaf, we'll see if we need to split leaf.
The check incorrectly reports that split leaf is required, because
it treats the space required by the newly inserted item as
btrfs_item + item data. But in item key collision case, only item data
is actually needed, the newly inserted item could merge into the existing
one. No new btrfs_item will be inserted.
And split_leaf return EOVERFLOW from following code:
if (extend && data_size + btrfs_item_size_nr(l, slot) +
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info))
return -EOVERFLOW;
In most cases, when callers receive EOVERFLOW, they either return
this error or handle in different ways. For example, in normal dir item
creation the userspace will get errno EOVERFLOW; in inode ref case
INODE_EXTREF is used instead.
However, this is not the case for rename. To avoid the unrecoverable
situation in rename, btrfs_check_dir_item_collision is called in
early phase of rename. In this function, when item key collision is
detected leaf space is checked:
data_size = sizeof(*di) + name_len;
if (data_size + btrfs_item_size_nr(leaf, slot) +
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info))
the sizeof(struct btrfs_item) + btrfs_item_size_nr(leaf, slot) here
refers to existing item size, the condition here correctly calculates
the needed size for collision case rather than the wrong case above.
The consequence of inconsistent condition check between
btrfs_check_dir_item_collision and btrfs_search_slot when item key
collision happens is that we might pass check here but fail
later at btrfs_search_slot. Rename fails and volume is forced readonly
[436149.586170] ------------[ cut here ]------------
[436149.586173] BTRFS: Transaction aborted (error -75)
[436149.586196] WARNING: CPU: 0 PID: 16733 at fs/btrfs/inode.c:9870 btrfs_rename2+0x1938/0x1b70 [btrfs]
[436149.586227] CPU: 0 PID: 16733 Comm: python Tainted: G D 4.18.0-rc5+ #1
[436149.586228] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016
[436149.586238] RIP: 0010:btrfs_rename2+0x1938/0x1b70 [btrfs]
[436149.586254] RSP: 0018:ffffa327043a7ce0 EFLAGS: 00010286
[436149.586255] RAX: 0000000000000000 RBX: ffff8d8a17d13340 RCX: 0000000000000006
[436149.586256] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff8d8a7fc164b0
[436149.586257] RBP: ffffa327043a7da0 R08: 0000000000000560 R09: 7265282064657472
[436149.586258] R10: 0000000000000000 R11: 6361736e61725420 R12: ffff8d8a0d4c8b08
[436149.586258] R13: ffff8d8a17d13340 R14: ffff8d8a33e0a540 R15: 00000000000001fe
[436149.586260] FS: 00007fa313933740(0000) GS:ffff8d8a7fc00000(0000) knlGS:0000000000000000
[436149.586261] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[436149.586262] CR2: 000055d8d9c9a720 CR3: 000000007aae0003 CR4: 00000000003606f0
[436149.586295] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[436149.586296] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[436149.586296] Call Trace:
[436149.586311] vfs_rename+0x383/0x920
[436149.586313] ? vfs_rename+0x383/0x920
[436149.586315] do_renameat2+0x4ca/0x590
[436149.586317] __x64_sys_rename+0x20/0x30
[436149.586324] do_syscall_64+0x5a/0x120
[436149.586330] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[436149.586332] RIP: 0033:0x7fa3133b1d37
[436149.586348] RSP: 002b:00007fffd3e43908 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
[436149.586349] RAX: ffffffffffffffda RBX: 00007fa3133b1d30 RCX: 00007fa3133b1d37
[436149.586350] RDX: 000055d8da06b5e0 RSI: 000055d8da225d60 RDI: 000055d8da2c4da0
[436149.586351] RBP: 000055d8da2252f0 R08: 00007fa313782000 R09: 00000000000177e0
[436149.586351] R10: 000055d8da010680 R11: 0000000000000246 R12: 00007fa313840b00
Thanks to Hans van Kranenburg for information about crc32 hash collision
tools, I was able to reproduce the dir item collision with following
python script.
https://github.com/wutzuchieh/misc_tools/blob/master/crc32_forge.py Run
it under a btrfs volume will trigger the abort transaction. It simply
creates files and rename them to forged names that leads to
hash collision.
There are two ways to fix this. One is to simply revert the patch
878f2d2cb355 ("Btrfs: fix max dir item size calculation") to make the
condition consistent although that patch is correct about the size.
The other way is to handle the leaf space check correctly when
collision happens. I prefer the second one since it correct leaf
space check in collision case. This fix will not account
sizeof(struct btrfs_item) when the item already exists.
There are two places where ins_len doesn't contain
sizeof(struct btrfs_item), however.
1. extent-tree.c: lookup_inline_extent_backref
2. file-item.c: btrfs_csum_file_blocks
to make the logic of btrfs_search_slot more clear, we add a flag
search_for_extension in btrfs_path.
This flag indicates that ins_len passed to btrfs_search_slot doesn't
contain sizeof(struct btrfs_item). When key exists, btrfs_search_slot
will use the actual size needed to calculate the required leaf space.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: ethanwu <ethanwu@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-01 09:25:12 +00:00
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/*
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* Indicate that new item (btrfs_search_slot) is extending already
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* existing item and ins_len contains only the data size and not item
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* header (ie. sizeof(struct btrfs_item) is not included).
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*/
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unsigned int search_for_extension:1;
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2022-09-12 19:27:42 +00:00
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/* Stop search if any locks need to be taken (for read) */
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unsigned int nowait:1;
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2007-02-02 14:18:22 +00:00
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};
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2022-09-14 23:04:46 +00:00
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2014-04-02 11:51:05 +00:00
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/*
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* The state of btrfs root
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*/
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2018-11-27 13:57:19 +00:00
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enum {
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/*
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* btrfs_record_root_in_trans is a multi-step process, and it can race
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* with the balancing code. But the race is very small, and only the
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* first time the root is added to each transaction. So IN_TRANS_SETUP
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* is used to tell us when more checks are required
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*/
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BTRFS_ROOT_IN_TRANS_SETUP,
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2020-05-15 06:01:40 +00:00
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/*
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* Set if tree blocks of this root can be shared by other roots.
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* Only subvolume trees and their reloc trees have this bit set.
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* Conflicts with TRACK_DIRTY bit.
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*
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* This affects two things:
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*
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* - How balance works
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* For shareable roots, we need to use reloc tree and do path
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* replacement for balance, and need various pre/post hooks for
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* snapshot creation to handle them.
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*
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* While for non-shareable trees, we just simply do a tree search
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* with COW.
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*
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* - How dirty roots are tracked
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* For shareable roots, btrfs_record_root_in_trans() is needed to
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* track them, while non-subvolume roots have TRACK_DIRTY bit, they
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* don't need to set this manually.
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*/
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BTRFS_ROOT_SHAREABLE,
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2018-11-27 13:57:19 +00:00
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BTRFS_ROOT_TRACK_DIRTY,
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2022-07-15 11:59:21 +00:00
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BTRFS_ROOT_IN_RADIX,
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2018-11-27 13:57:19 +00:00
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BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
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BTRFS_ROOT_DEFRAG_RUNNING,
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BTRFS_ROOT_FORCE_COW,
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BTRFS_ROOT_MULTI_LOG_TASKS,
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BTRFS_ROOT_DIRTY,
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2018-11-30 16:52:13 +00:00
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BTRFS_ROOT_DELETING,
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2019-01-23 07:15:14 +00:00
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/*
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* Reloc tree is orphan, only kept here for qgroup delayed subtree scan
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*
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* Set for the subvolume tree owning the reloc tree.
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*/
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BTRFS_ROOT_DEAD_RELOC_TREE,
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2019-02-06 20:46:14 +00:00
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/* Mark dead root stored on device whose cleanup needs to be resumed */
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BTRFS_ROOT_DEAD_TREE,
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btrfs: do not block inode logging for so long during transaction commit
Early on during a transaction commit we acquire the tree_log_mutex and
hold it until after we write the super blocks. But before writing the
extent buffers dirtied by the transaction and the super blocks we unblock
the transaction by setting its state to TRANS_STATE_UNBLOCKED and setting
fs_info->running_transaction to NULL.
This means that after that and before writing the super blocks, new
transactions can start. However if any transaction wants to log an inode,
it will block waiting for the transaction commit to write its dirty
extent buffers and the super blocks because the tree_log_mutex is only
released after those operations are complete, and starting a new log
transaction blocks on that mutex (at start_log_trans()).
Writing the dirty extent buffers and the super blocks can take a very
significant amount of time to complete, but we could allow the tasks
wanting to log an inode to proceed with most of their steps:
1) create the log trees
2) log metadata in the trees
3) write their dirty extent buffers
They only need to wait for the previous transaction commit to complete
(write its super blocks) before they attempt to write their super blocks,
otherwise we could end up with a corrupt filesystem after a crash.
So change start_log_trans() to use the root tree's log_mutex to serialize
for the creation of the log root tree instead of using the tree_log_mutex,
and make btrfs_sync_log() acquire the tree_log_mutex before writing the
super blocks. This allows for inode logging to wait much less time when
there is a previous transaction that is still committing, often not having
to wait at all, as by the time when we try to sync the log the previous
transaction already wrote its super blocks.
This patch belongs to a patch set that is comprised of the following
patches:
btrfs: fix race causing unnecessary inode logging during link and rename
btrfs: fix race that results in logging old extents during a fast fsync
btrfs: fix race that causes unnecessary logging of ancestor inodes
btrfs: fix race that makes inode logging fallback to transaction commit
btrfs: fix race leading to unnecessary transaction commit when logging inode
btrfs: do not block inode logging for so long during transaction commit
The following script that uses dbench was used to measure the impact of
the whole patchset:
$ cat test-dbench.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/btrfs
MOUNT_OPTIONS="-o ssd"
echo "performance" | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
mkfs.btrfs -f -m single -d single $DEV
mount $MOUNT_OPTIONS $DEV $MNT
dbench -D $MNT -t 300 64
umount $MNT
The test was run on a machine with 12 cores, 64G of ram, using a NVMe
device and a non-debug kernel configuration (Debian's default).
Before patch set:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 11277211 0.250 85.340
Close 8283172 0.002 6.479
Rename 477515 1.935 86.026
Unlink 2277936 0.770 87.071
Deltree 256 15.732 81.379
Mkdir 128 0.003 0.009
Qpathinfo 10221180 0.056 44.404
Qfileinfo 1789967 0.002 4.066
Qfsinfo 1874399 0.003 9.176
Sfileinfo 918589 0.061 10.247
Find 3951758 0.341 54.040
WriteX 5616547 0.047 85.079
ReadX 17676028 0.005 9.704
LockX 36704 0.003 1.800
UnlockX 36704 0.002 0.687
Flush 790541 14.115 676.236
Throughput 1179.19 MB/sec 64 clients 64 procs max_latency=676.240 ms
After patch set:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 12687926 0.171 86.526
Close 9320780 0.002 8.063
Rename 537253 1.444 78.576
Unlink 2561827 0.559 87.228
Deltree 374 11.499 73.549
Mkdir 187 0.003 0.005
Qpathinfo 11500300 0.061 36.801
Qfileinfo 2017118 0.002 7.189
Qfsinfo 2108641 0.003 4.825
Sfileinfo 1033574 0.008 8.065
Find 4446553 0.408 47.835
WriteX 6335667 0.045 84.388
ReadX 19887312 0.003 9.215
LockX 41312 0.003 1.394
UnlockX 41312 0.002 1.425
Flush 889233 13.014 623.259
Throughput 1339.32 MB/sec 64 clients 64 procs max_latency=623.265 ms
+12.7% throughput, -8.2% max latency
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-25 12:19:28 +00:00
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/* The root has a log tree. Used for subvolume roots and the tree root. */
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2020-06-15 09:38:44 +00:00
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BTRFS_ROOT_HAS_LOG_TREE,
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btrfs: qgroup: try to flush qgroup space when we get -EDQUOT
[PROBLEM]
There are known problem related to how btrfs handles qgroup reserved
space. One of the most obvious case is the the test case btrfs/153,
which do fallocate, then write into the preallocated range.
btrfs/153 1s ... - output mismatch (see xfstests-dev/results//btrfs/153.out.bad)
--- tests/btrfs/153.out 2019-10-22 15:18:14.068965341 +0800
+++ xfstests-dev/results//btrfs/153.out.bad 2020-07-01 20:24:40.730000089 +0800
@@ -1,2 +1,5 @@
QA output created by 153
+pwrite: Disk quota exceeded
+/mnt/scratch/testfile2: Disk quota exceeded
+/mnt/scratch/testfile2: Disk quota exceeded
Silence is golden
...
(Run 'diff -u xfstests-dev/tests/btrfs/153.out xfstests-dev/results//btrfs/153.out.bad' to see the entire diff)
[CAUSE]
Since commit c6887cd11149 ("Btrfs: don't do nocow check unless we have to"),
we always reserve space no matter if it's COW or not.
Such behavior change is mostly for performance, and reverting it is not
a good idea anyway.
For preallcoated extent, we reserve qgroup data space for it already,
and since we also reserve data space for qgroup at buffered write time,
it needs twice the space for us to write into preallocated space.
This leads to the -EDQUOT in buffered write routine.
And we can't follow the same solution, unlike data/meta space check,
qgroup reserved space is shared between data/metadata.
The EDQUOT can happen at the metadata reservation, so doing NODATACOW
check after qgroup reservation failure is not a solution.
[FIX]
To solve the problem, we don't return -EDQUOT directly, but every time
we got a -EDQUOT, we try to flush qgroup space:
- Flush all inodes of the root
NODATACOW writes will free the qgroup reserved at run_dealloc_range().
However we don't have the infrastructure to only flush NODATACOW
inodes, here we flush all inodes anyway.
- Wait for ordered extents
This would convert the preallocated metadata space into per-trans
metadata, which can be freed in later transaction commit.
- Commit transaction
This will free all per-trans metadata space.
Also we don't want to trigger flush multiple times, so here we introduce
a per-root wait list and a new root status, to ensure only one thread
starts the flushing.
Fixes: c6887cd11149 ("Btrfs: don't do nocow check unless we have to")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-13 10:50:48 +00:00
|
|
|
/* Qgroup flushing is in progress */
|
|
|
|
BTRFS_ROOT_QGROUP_FLUSHING,
|
2021-11-09 15:12:06 +00:00
|
|
|
/* We started the orphan cleanup for this root. */
|
|
|
|
BTRFS_ROOT_ORPHAN_CLEANUP,
|
2022-02-18 19:56:10 +00:00
|
|
|
/* This root has a drop operation that was started previously. */
|
|
|
|
BTRFS_ROOT_UNFINISHED_DROP,
|
btrfs: fix lockdep splat with reloc root extent buffers
We have been hitting the following lockdep splat with btrfs/187 recently
WARNING: possible circular locking dependency detected
5.19.0-rc8+ #775 Not tainted
------------------------------------------------------
btrfs/752500 is trying to acquire lock:
ffff97e1875a97b8 (btrfs-treloc-02#2){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110
but task is already holding lock:
ffff97e1875a9278 (btrfs-tree-01/1){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (btrfs-tree-01/1){+.+.}-{3:3}:
down_write_nested+0x41/0x80
__btrfs_tree_lock+0x24/0x110
btrfs_init_new_buffer+0x7d/0x2c0
btrfs_alloc_tree_block+0x120/0x3b0
__btrfs_cow_block+0x136/0x600
btrfs_cow_block+0x10b/0x230
btrfs_search_slot+0x53b/0xb70
btrfs_lookup_inode+0x2a/0xa0
__btrfs_update_delayed_inode+0x5f/0x280
btrfs_async_run_delayed_root+0x24c/0x290
btrfs_work_helper+0xf2/0x3e0
process_one_work+0x271/0x590
worker_thread+0x52/0x3b0
kthread+0xf0/0x120
ret_from_fork+0x1f/0x30
-> #1 (btrfs-tree-01){++++}-{3:3}:
down_write_nested+0x41/0x80
__btrfs_tree_lock+0x24/0x110
btrfs_search_slot+0x3c3/0xb70
do_relocation+0x10c/0x6b0
relocate_tree_blocks+0x317/0x6d0
relocate_block_group+0x1f1/0x560
btrfs_relocate_block_group+0x23e/0x400
btrfs_relocate_chunk+0x4c/0x140
btrfs_balance+0x755/0xe40
btrfs_ioctl+0x1ea2/0x2c90
__x64_sys_ioctl+0x88/0xc0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #0 (btrfs-treloc-02#2){+.+.}-{3:3}:
__lock_acquire+0x1122/0x1e10
lock_acquire+0xc2/0x2d0
down_write_nested+0x41/0x80
__btrfs_tree_lock+0x24/0x110
btrfs_lock_root_node+0x31/0x50
btrfs_search_slot+0x1cb/0xb70
replace_path+0x541/0x9f0
merge_reloc_root+0x1d6/0x610
merge_reloc_roots+0xe2/0x260
relocate_block_group+0x2c8/0x560
btrfs_relocate_block_group+0x23e/0x400
btrfs_relocate_chunk+0x4c/0x140
btrfs_balance+0x755/0xe40
btrfs_ioctl+0x1ea2/0x2c90
__x64_sys_ioctl+0x88/0xc0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Chain exists of:
btrfs-treloc-02#2 --> btrfs-tree-01 --> btrfs-tree-01/1
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(btrfs-tree-01/1);
lock(btrfs-tree-01);
lock(btrfs-tree-01/1);
lock(btrfs-treloc-02#2);
*** DEADLOCK ***
7 locks held by btrfs/752500:
#0: ffff97e292fdf460 (sb_writers#12){.+.+}-{0:0}, at: btrfs_ioctl+0x208/0x2c90
#1: ffff97e284c02050 (&fs_info->reclaim_bgs_lock){+.+.}-{3:3}, at: btrfs_balance+0x55f/0xe40
#2: ffff97e284c00878 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: btrfs_relocate_block_group+0x236/0x400
#3: ffff97e292fdf650 (sb_internal#2){.+.+}-{0:0}, at: merge_reloc_root+0xef/0x610
#4: ffff97e284c02378 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x1a8/0x5a0
#5: ffff97e284c023a0 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x1a8/0x5a0
#6: ffff97e1875a9278 (btrfs-tree-01/1){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110
stack backtrace:
CPU: 1 PID: 752500 Comm: btrfs Not tainted 5.19.0-rc8+ #775
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
dump_stack_lvl+0x56/0x73
check_noncircular+0xd6/0x100
? lock_is_held_type+0xe2/0x140
__lock_acquire+0x1122/0x1e10
lock_acquire+0xc2/0x2d0
? __btrfs_tree_lock+0x24/0x110
down_write_nested+0x41/0x80
? __btrfs_tree_lock+0x24/0x110
__btrfs_tree_lock+0x24/0x110
btrfs_lock_root_node+0x31/0x50
btrfs_search_slot+0x1cb/0xb70
? lock_release+0x137/0x2d0
? _raw_spin_unlock+0x29/0x50
? release_extent_buffer+0x128/0x180
replace_path+0x541/0x9f0
merge_reloc_root+0x1d6/0x610
merge_reloc_roots+0xe2/0x260
relocate_block_group+0x2c8/0x560
btrfs_relocate_block_group+0x23e/0x400
btrfs_relocate_chunk+0x4c/0x140
btrfs_balance+0x755/0xe40
btrfs_ioctl+0x1ea2/0x2c90
? lock_is_held_type+0xe2/0x140
? lock_is_held_type+0xe2/0x140
? __x64_sys_ioctl+0x88/0xc0
__x64_sys_ioctl+0x88/0xc0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
This isn't necessarily new, it's just tricky to hit in practice. There
are two competing things going on here. With relocation we create a
snapshot of every fs tree with a reloc tree. Any extent buffers that
get initialized here are initialized with the reloc root lockdep key.
However since it is a snapshot, any blocks that are currently in cache
that originally belonged to the fs tree will have the normal tree
lockdep key set. This creates the lock dependency of
reloc tree -> normal tree
for the extent buffer locking during the first phase of the relocation
as we walk down the reloc root to relocate blocks.
However this is problematic because the final phase of the relocation is
merging the reloc root into the original fs root. This involves
searching down to any keys that exist in the original fs root and then
swapping the relocated block and the original fs root block. We have to
search down to the fs root first, and then go search the reloc root for
the block we need to replace. This creates the dependency of
normal tree -> reloc tree
which is why lockdep complains.
Additionally even if we were to fix this particular mismatch with a
different nesting for the merge case, we're still slotting in a block
that has a owner of the reloc root objectid into a normal tree, so that
block will have its lockdep key set to the tree reloc root, and create a
lockdep splat later on when we wander into that block from the fs root.
Unfortunately the only solution here is to make sure we do not set the
lockdep key to the reloc tree lockdep key normally, and then reset any
blocks we wander into from the reloc root when we're doing the merged.
This solves the problem of having mixed tree reloc keys intermixed with
normal tree keys, and then allows us to make sure in the merge case we
maintain the lock order of
normal tree -> reloc tree
We handle this by setting a bit on the reloc root when we do the search
for the block we want to relocate, and any block we search into or COW
at that point gets set to the reloc tree key. This works correctly
because we only ever COW down to the parent node, so we aren't resetting
the key for the block we're linking into the fs root.
With this patch we no longer have the lockdep splat in btrfs/187.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-26 20:24:04 +00:00
|
|
|
/* This reloc root needs to have its buffers lockdep class reset. */
|
|
|
|
BTRFS_ROOT_RESET_LOCKDEP_CLASS,
|
2018-11-27 13:57:19 +00:00
|
|
|
};
|
2014-04-02 11:51:05 +00:00
|
|
|
|
btrfs: qgroup: Introduce per-root swapped blocks infrastructure
To allow delayed subtree swap rescan, btrfs needs to record per-root
information about which tree blocks get swapped. This patch introduces
the required infrastructure.
The designed workflow will be:
1) Record the subtree root block that gets swapped.
During subtree swap:
O = Old tree blocks
N = New tree blocks
reloc tree subvolume tree X
Root Root
/ \ / \
NA OB OA OB
/ | | \ / | | \
NC ND OE OF OC OD OE OF
In this case, NA and OA are going to be swapped, record (NA, OA) into
subvolume tree X.
2) After subtree swap.
reloc tree subvolume tree X
Root Root
/ \ / \
OA OB NA OB
/ | | \ / | | \
OC OD OE OF NC ND OE OF
3a) COW happens for OB
If we are going to COW tree block OB, we check OB's bytenr against
tree X's swapped_blocks structure.
If it doesn't fit any, nothing will happen.
3b) COW happens for NA
Check NA's bytenr against tree X's swapped_blocks, and get a hit.
Then we do subtree scan on both subtrees OA and NA.
Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND).
Then no matter what we do to subvolume tree X, qgroup numbers will
still be correct.
Then NA's record gets removed from X's swapped_blocks.
4) Transaction commit
Any record in X's swapped_blocks gets removed, since there is no
modification to swapped subtrees, no need to trigger heavy qgroup
subtree rescan for them.
This will introduce 128 bytes overhead for each btrfs_root even qgroup
is not enabled. This is to reduce memory allocations and potential
failures.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-23 07:15:16 +00:00
|
|
|
/*
|
|
|
|
* Record swapped tree blocks of a subvolume tree for delayed subtree trace
|
|
|
|
* code. For detail check comment in fs/btrfs/qgroup.c.
|
|
|
|
*/
|
|
|
|
struct btrfs_qgroup_swapped_blocks {
|
|
|
|
spinlock_t lock;
|
|
|
|
/* RM_EMPTY_ROOT() of above blocks[] */
|
|
|
|
bool swapped;
|
|
|
|
struct rb_root blocks[BTRFS_MAX_LEVEL];
|
|
|
|
};
|
|
|
|
|
2007-03-20 18:38:32 +00:00
|
|
|
/*
|
|
|
|
* in ram representation of the tree. extent_root is used for all allocations
|
2007-04-25 19:52:25 +00:00
|
|
|
* and for the extent tree extent_root root.
|
2007-03-20 18:38:32 +00:00
|
|
|
*/
|
|
|
|
struct btrfs_root {
|
2021-11-05 20:45:51 +00:00
|
|
|
struct rb_node rb_node;
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *node;
|
2008-06-25 20:01:30 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *commit_root;
|
2008-09-05 20:13:11 +00:00
|
|
|
struct btrfs_root *log_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;
|
2008-07-28 19:32:19 +00:00
|
|
|
|
2014-04-02 11:51:05 +00:00
|
|
|
unsigned long state;
|
2007-03-15 16:56:47 +00:00
|
|
|
struct btrfs_root_item root_item;
|
|
|
|
struct btrfs_key root_key;
|
2007-03-20 18:38:32 +00:00
|
|
|
struct btrfs_fs_info *fs_info;
|
2008-09-11 20:17:57 +00:00
|
|
|
struct extent_io_tree dirty_log_pages;
|
|
|
|
|
2008-06-25 20:01:30 +00:00
|
|
|
struct mutex objectid_mutex;
|
2009-01-21 17:54:03 +00:00
|
|
|
|
2010-05-16 14:46:25 +00:00
|
|
|
spinlock_t accounting_lock;
|
|
|
|
struct btrfs_block_rsv *block_rsv;
|
|
|
|
|
2008-09-05 20:13:11 +00:00
|
|
|
struct mutex log_mutex;
|
2009-01-21 17:54:03 +00:00
|
|
|
wait_queue_head_t log_writer_wait;
|
|
|
|
wait_queue_head_t log_commit_wait[2];
|
2014-02-20 10:08:58 +00:00
|
|
|
struct list_head log_ctxs[2];
|
btrfs: remove no longer needed use of log_writers for the log root tree
When syncing the log, we used to update the log root tree without holding
neither the log_mutex of the subvolume root nor the log_mutex of log root
tree.
We used to have two critical sections delimited by the log_mutex of the
log root tree, so in the first one we incremented the log_writers of the
log root tree and on the second one we decremented it and waited for the
log_writers counter to go down to zero. This was because the update of
the log root tree happened between the two critical sections.
The use of two critical sections allowed a little bit more of parallelism
and required the use of the log_writers counter, necessary to make sure
we didn't miss any log root tree update when we have multiple tasks trying
to sync the log in parallel.
However after commit 06989c799f0481 ("Btrfs: fix race updating log root
item during fsync") the log root tree update was moved into a critical
section delimited by the subvolume's log_mutex. Later another commit
moved the log tree update from that critical section into the second
critical section delimited by the log_mutex of the log root tree. Both
commits addressed different bugs.
The end result is that the first critical section delimited by the
log_mutex of the log root tree became pointless, since there's nothing
done between it and the second critical section, we just have an unlock
of the log_mutex followed by a lock operation. This means we can merge
both critical sections, as the first one does almost nothing now, and we
can stop using the log_writers counter of the log root tree, which was
incremented in the first critical section and decremented in the second
criticial section, used to make sure no one in the second critical section
started writeback of the log root tree before some other task updated it.
So just remove the mutex_unlock() followed by mutex_lock() of the log root
tree, as well as the use of the log_writers counter for the log root tree.
This patch is part of a series that has the following patches:
1/4 btrfs: only commit the delayed inode when doing a full fsync
2/4 btrfs: only commit delayed items at fsync if we are logging a directory
3/4 btrfs: stop incremening log_batch for the log root tree when syncing log
4/4 btrfs: remove no longer needed use of log_writers for the log root tree
After the entire patchset applied I saw about 12% decrease on max latency
reported by dbench. The test was done on a qemu vm, with 8 cores, 16Gb of
ram, using kvm and using a raw NVMe device directly (no intermediary fs on
the host). The test was invoked like the following:
mkfs.btrfs -f /dev/sdk
mount -o ssd -o nospace_cache /dev/sdk /mnt/sdk
dbench -D /mnt/sdk -t 300 8
umount /mnt/dsk
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-02 11:32:40 +00:00
|
|
|
/* Used only for log trees of subvolumes, not for the log root tree */
|
2009-01-21 17:54:03 +00:00
|
|
|
atomic_t log_writers;
|
|
|
|
atomic_t log_commit[2];
|
2020-07-02 11:32:31 +00:00
|
|
|
/* Used only for log trees of subvolumes, not for the log root tree */
|
2012-09-06 10:04:27 +00:00
|
|
|
atomic_t log_batch;
|
2023-10-04 10:38:49 +00:00
|
|
|
/*
|
|
|
|
* Protected by the 'log_mutex' lock but can be read without holding
|
|
|
|
* that lock to avoid unnecessary lock contention, in which case it
|
|
|
|
* should be read using btrfs_get_root_log_transid() except if it's a
|
|
|
|
* log tree in which case it can be directly accessed. Updates to this
|
|
|
|
* field should always use btrfs_set_root_log_transid(), except for log
|
|
|
|
* trees where the field can be updated directly.
|
|
|
|
*/
|
2014-02-20 10:08:56 +00:00
|
|
|
int log_transid;
|
2014-02-20 10:08:59 +00:00
|
|
|
/* No matter the commit succeeds or not*/
|
|
|
|
int log_transid_committed;
|
2023-10-04 10:38:48 +00:00
|
|
|
/*
|
|
|
|
* Just be updated when the commit succeeds. Use
|
|
|
|
* btrfs_get_root_last_log_commit() and btrfs_set_root_last_log_commit()
|
|
|
|
* to access this field.
|
|
|
|
*/
|
2014-02-20 10:08:56 +00:00
|
|
|
int last_log_commit;
|
2009-10-08 19:30:04 +00:00
|
|
|
pid_t log_start_pid;
|
2008-08-05 03:17:27 +00:00
|
|
|
|
2007-04-09 14:42:37 +00:00
|
|
|
u64 last_trans;
|
2007-10-15 20:14:19 +00:00
|
|
|
|
2020-12-07 15:32:35 +00:00
|
|
|
u64 free_objectid;
|
2011-06-14 00:00:16 +00:00
|
|
|
|
2007-08-07 20:15:09 +00:00
|
|
|
struct btrfs_key defrag_progress;
|
2008-05-24 18:04:53 +00:00
|
|
|
struct btrfs_key defrag_max;
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2020-05-15 06:01:40 +00:00
|
|
|
/* The dirty list is only used by non-shareable roots */
|
2008-03-24 19:01:56 +00:00
|
|
|
struct list_head dirty_list;
|
2008-07-24 16:17:14 +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 list_head root_list;
|
|
|
|
|
|
|
|
spinlock_t inode_lock;
|
|
|
|
/* red-black tree that keeps track of in-memory inodes */
|
|
|
|
struct rb_root inode_tree;
|
|
|
|
|
btrfs: implement delayed inode items operation
Changelog V5 -> V6:
- Fix oom when the memory load is high, by storing the delayed nodes into the
root's radix tree, and letting btrfs inodes go.
Changelog V4 -> V5:
- Fix the race on adding the delayed node to the inode, which is spotted by
Chris Mason.
- Merge Chris Mason's incremental patch into this patch.
- Fix deadlock between readdir() and memory fault, which is reported by
Itaru Kitayama.
Changelog V3 -> V4:
- Fix nested lock, which is reported by Itaru Kitayama, by updating space cache
inode in time.
Changelog V2 -> V3:
- Fix the race between the delayed worker and the task which does delayed items
balance, which is reported by Tsutomu Itoh.
- Modify the patch address David Sterba's comment.
- Fix the bug of the cpu recursion spinlock, reported by Chris Mason
Changelog V1 -> V2:
- break up the global rb-tree, use a list to manage the delayed nodes,
which is created for every directory and file, and used to manage the
delayed directory name index items and the delayed inode item.
- introduce a worker to deal with the delayed nodes.
Compare with Ext3/4, the performance of file creation and deletion on btrfs
is very poor. the reason is that btrfs must do a lot of b+ tree insertions,
such as inode item, directory name item, directory name index and so on.
If we can do some delayed b+ tree insertion or deletion, we can improve the
performance, so we made this patch which implemented delayed directory name
index insertion/deletion and delayed inode update.
Implementation:
- introduce a delayed root object into the filesystem, that use two lists to
manage the delayed nodes which are created for every file/directory.
One is used to manage all the delayed nodes that have delayed items. And the
other is used to manage the delayed nodes which is waiting to be dealt with
by the work thread.
- Every delayed node has two rb-tree, one is used to manage the directory name
index which is going to be inserted into b+ tree, and the other is used to
manage the directory name index which is going to be deleted from b+ tree.
- introduce a worker to deal with the delayed operation. This worker is used
to deal with the works of the delayed directory name index items insertion
and deletion and the delayed inode update.
When the delayed items is beyond the lower limit, we create works for some
delayed nodes and insert them into the work queue of the worker, and then
go back.
When the delayed items is beyond the upper bound, we create works for all
the delayed nodes that haven't been dealt with, and insert them into the work
queue of the worker, and then wait for that the untreated items is below some
threshold value.
- When we want to insert a directory name index into b+ tree, we just add the
information into the delayed inserting rb-tree.
And then we check the number of the delayed items and do delayed items
balance. (The balance policy is above.)
- When we want to delete a directory name index from the b+ tree, we search it
in the inserting rb-tree at first. If we look it up, just drop it. If not,
add the key of it into the delayed deleting rb-tree.
Similar to the delayed inserting rb-tree, we also check the number of the
delayed items and do delayed items balance.
(The same to inserting manipulation)
- When we want to update the metadata of some inode, we cached the data of the
inode into the delayed node. the worker will flush it into the b+ tree after
dealing with the delayed insertion and deletion.
- We will move the delayed node to the tail of the list after we access the
delayed node, By this way, we can cache more delayed items and merge more
inode updates.
- If we want to commit transaction, we will deal with all the delayed node.
- the delayed node will be freed when we free the btrfs inode.
- Before we log the inode items, we commit all the directory name index items
and the delayed inode update.
I did a quick test by the benchmark tool[1] and found we can improve the
performance of file creation by ~15%, and file deletion by ~20%.
Before applying this patch:
Create files:
Total files: 50000
Total time: 1.096108
Average time: 0.000022
Delete files:
Total files: 50000
Total time: 1.510403
Average time: 0.000030
After applying this patch:
Create files:
Total files: 50000
Total time: 0.932899
Average time: 0.000019
Delete files:
Total files: 50000
Total time: 1.215732
Average time: 0.000024
[1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3
Many thanks for Kitayama-san's help!
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: David Sterba <dave@jikos.cz>
Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Tested-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-22 10:12:22 +00:00
|
|
|
/*
|
2023-12-06 14:16:03 +00:00
|
|
|
* Xarray that keeps track of delayed nodes of every inode, protected
|
|
|
|
* by @inode_lock.
|
btrfs: implement delayed inode items operation
Changelog V5 -> V6:
- Fix oom when the memory load is high, by storing the delayed nodes into the
root's radix tree, and letting btrfs inodes go.
Changelog V4 -> V5:
- Fix the race on adding the delayed node to the inode, which is spotted by
Chris Mason.
- Merge Chris Mason's incremental patch into this patch.
- Fix deadlock between readdir() and memory fault, which is reported by
Itaru Kitayama.
Changelog V3 -> V4:
- Fix nested lock, which is reported by Itaru Kitayama, by updating space cache
inode in time.
Changelog V2 -> V3:
- Fix the race between the delayed worker and the task which does delayed items
balance, which is reported by Tsutomu Itoh.
- Modify the patch address David Sterba's comment.
- Fix the bug of the cpu recursion spinlock, reported by Chris Mason
Changelog V1 -> V2:
- break up the global rb-tree, use a list to manage the delayed nodes,
which is created for every directory and file, and used to manage the
delayed directory name index items and the delayed inode item.
- introduce a worker to deal with the delayed nodes.
Compare with Ext3/4, the performance of file creation and deletion on btrfs
is very poor. the reason is that btrfs must do a lot of b+ tree insertions,
such as inode item, directory name item, directory name index and so on.
If we can do some delayed b+ tree insertion or deletion, we can improve the
performance, so we made this patch which implemented delayed directory name
index insertion/deletion and delayed inode update.
Implementation:
- introduce a delayed root object into the filesystem, that use two lists to
manage the delayed nodes which are created for every file/directory.
One is used to manage all the delayed nodes that have delayed items. And the
other is used to manage the delayed nodes which is waiting to be dealt with
by the work thread.
- Every delayed node has two rb-tree, one is used to manage the directory name
index which is going to be inserted into b+ tree, and the other is used to
manage the directory name index which is going to be deleted from b+ tree.
- introduce a worker to deal with the delayed operation. This worker is used
to deal with the works of the delayed directory name index items insertion
and deletion and the delayed inode update.
When the delayed items is beyond the lower limit, we create works for some
delayed nodes and insert them into the work queue of the worker, and then
go back.
When the delayed items is beyond the upper bound, we create works for all
the delayed nodes that haven't been dealt with, and insert them into the work
queue of the worker, and then wait for that the untreated items is below some
threshold value.
- When we want to insert a directory name index into b+ tree, we just add the
information into the delayed inserting rb-tree.
And then we check the number of the delayed items and do delayed items
balance. (The balance policy is above.)
- When we want to delete a directory name index from the b+ tree, we search it
in the inserting rb-tree at first. If we look it up, just drop it. If not,
add the key of it into the delayed deleting rb-tree.
Similar to the delayed inserting rb-tree, we also check the number of the
delayed items and do delayed items balance.
(The same to inserting manipulation)
- When we want to update the metadata of some inode, we cached the data of the
inode into the delayed node. the worker will flush it into the b+ tree after
dealing with the delayed insertion and deletion.
- We will move the delayed node to the tail of the list after we access the
delayed node, By this way, we can cache more delayed items and merge more
inode updates.
- If we want to commit transaction, we will deal with all the delayed node.
- the delayed node will be freed when we free the btrfs inode.
- Before we log the inode items, we commit all the directory name index items
and the delayed inode update.
I did a quick test by the benchmark tool[1] and found we can improve the
performance of file creation by ~15%, and file deletion by ~20%.
Before applying this patch:
Create files:
Total files: 50000
Total time: 1.096108
Average time: 0.000022
Delete files:
Total files: 50000
Total time: 1.510403
Average time: 0.000030
After applying this patch:
Create files:
Total files: 50000
Total time: 0.932899
Average time: 0.000019
Delete files:
Total files: 50000
Total time: 1.215732
Average time: 0.000024
[1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3
Many thanks for Kitayama-san's help!
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: David Sterba <dave@jikos.cz>
Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Tested-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-22 10:12:22 +00:00
|
|
|
*/
|
2023-12-06 14:16:03 +00:00
|
|
|
struct xarray delayed_nodes;
|
2008-11-18 01:42:26 +00:00
|
|
|
/*
|
|
|
|
* right now this just gets used so that a root has its own devid
|
|
|
|
* for stat. It may be used for more later
|
|
|
|
*/
|
2011-07-07 19:44:25 +00:00
|
|
|
dev_t anon_dev;
|
2011-11-15 01:48:06 +00:00
|
|
|
|
2012-12-07 09:28:54 +00:00
|
|
|
spinlock_t root_item_lock;
|
2017-03-03 08:55:18 +00:00
|
|
|
refcount_t refs;
|
2013-05-15 07:48:22 +00:00
|
|
|
|
2014-03-06 05:55:03 +00:00
|
|
|
struct mutex delalloc_mutex;
|
2013-05-15 07:48:22 +00:00
|
|
|
spinlock_t delalloc_lock;
|
|
|
|
/*
|
|
|
|
* all of the inodes that have delalloc bytes. It is possible for
|
|
|
|
* this list to be empty even when there is still dirty data=ordered
|
|
|
|
* extents waiting to finish IO.
|
|
|
|
*/
|
|
|
|
struct list_head delalloc_inodes;
|
|
|
|
struct list_head delalloc_root;
|
|
|
|
u64 nr_delalloc_inodes;
|
2014-03-06 05:55:02 +00:00
|
|
|
|
|
|
|
struct mutex ordered_extent_mutex;
|
2013-05-15 07:48:23 +00:00
|
|
|
/*
|
|
|
|
* this is used by the balancing code to wait for all the pending
|
|
|
|
* ordered extents
|
|
|
|
*/
|
|
|
|
spinlock_t ordered_extent_lock;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* all of the data=ordered extents pending writeback
|
|
|
|
* these can span multiple transactions and basically include
|
|
|
|
* every dirty data page that isn't from nodatacow
|
|
|
|
*/
|
|
|
|
struct list_head ordered_extents;
|
|
|
|
struct list_head ordered_root;
|
|
|
|
u64 nr_ordered_extents;
|
2013-12-16 16:34:17 +00:00
|
|
|
|
2019-01-23 07:15:14 +00:00
|
|
|
/*
|
|
|
|
* Not empty if this subvolume root has gone through tree block swap
|
|
|
|
* (relocation)
|
|
|
|
*
|
|
|
|
* Will be used by reloc_control::dirty_subvol_roots.
|
|
|
|
*/
|
|
|
|
struct list_head reloc_dirty_list;
|
|
|
|
|
2013-12-16 16:34:17 +00:00
|
|
|
/*
|
|
|
|
* Number of currently running SEND ioctls to prevent
|
|
|
|
* manipulation with the read-only status via SUBVOL_SETFLAGS
|
|
|
|
*/
|
|
|
|
int send_in_progress;
|
Btrfs: fix race between send and deduplication that lead to failures and crashes
Send operates on read only trees and expects them to never change while it
is using them. This is part of its initial design, and this expection is
due to two different reasons:
1) When it was introduced, no operations were allowed to modifiy read-only
subvolumes/snapshots (including defrag for example).
2) It keeps send from having an impact on other filesystem operations.
Namely send does not need to keep locks on the trees nor needs to hold on
to transaction handles and delay transaction commits. This ends up being
a consequence of the former reason.
However the deduplication feature was introduced later (on September 2013,
while send was introduced in July 2012) and it allowed for deduplication
with destination files that belong to read-only trees (subvolumes and
snapshots).
That means that having a send operation (either full or incremental) running
in parallel with a deduplication that has the destination inode in one of
the trees used by the send operation, can result in tree nodes and leaves
getting freed and reused while send is using them. This problem is similar
to the problem solved for the root nodes getting freed and reused when a
snapshot is made against one tree that is currenly being used by a send
operation, fixed in commits [1] and [2]. These commits explain in detail
how the problem happens and the explanation is valid for any node or leaf
that is not the root of a tree as well. This problem was also discussed
and explained recently in a thread [3].
The problem is very easy to reproduce when using send with large trees
(snapshots) and just a few concurrent deduplication operations that target
files in the trees used by send. A stress test case is being sent for
fstests that triggers the issue easily. The most common error to hit is
the send ioctl return -EIO with the following messages in dmesg/syslog:
[1631617.204075] BTRFS error (device sdc): did not find backref in send_root. inode=63292, offset=0, disk_byte=5228134400 found extent=5228134400
[1631633.251754] BTRFS error (device sdc): parent transid verify failed on 32243712 wanted 24 found 27
The first one is very easy to hit while the second one happens much less
frequently, except for very large trees (in that test case, snapshots
with 100000 files having large xattrs to get deep and wide trees).
Less frequently, at least one BUG_ON can be hit:
[1631742.130080] ------------[ cut here ]------------
[1631742.130625] kernel BUG at fs/btrfs/ctree.c:1806!
[1631742.131188] invalid opcode: 0000 [#6] SMP DEBUG_PAGEALLOC PTI
[1631742.131726] CPU: 1 PID: 13394 Comm: btrfs Tainted: G B D W 5.0.0-rc8-btrfs-next-45 #1
[1631742.132265] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[1631742.133399] RIP: 0010:read_node_slot+0x122/0x130 [btrfs]
(...)
[1631742.135061] RSP: 0018:ffffb530021ebaa0 EFLAGS: 00010246
[1631742.135615] RAX: ffff93ac8912e000 RBX: 000000000000009d RCX: 0000000000000002
[1631742.136173] RDX: 000000000000009d RSI: ffff93ac564b0d08 RDI: ffff93ad5b48c000
[1631742.136759] RBP: ffffb530021ebb7d R08: 0000000000000001 R09: ffffb530021ebb7d
[1631742.137324] R10: ffffb530021eba70 R11: 0000000000000000 R12: ffff93ac87d0a708
[1631742.137900] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
[1631742.138455] FS: 00007f4cdb1528c0(0000) GS:ffff93ad76a80000(0000) knlGS:0000000000000000
[1631742.139010] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1631742.139568] CR2: 00007f5acb3d0420 CR3: 000000012be3e006 CR4: 00000000003606e0
[1631742.140131] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[1631742.140719] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[1631742.141272] Call Trace:
[1631742.141826] ? do_raw_spin_unlock+0x49/0xc0
[1631742.142390] tree_advance+0x173/0x1d0 [btrfs]
[1631742.142948] btrfs_compare_trees+0x268/0x690 [btrfs]
[1631742.143533] ? process_extent+0x1070/0x1070 [btrfs]
[1631742.144088] btrfs_ioctl_send+0x1037/0x1270 [btrfs]
[1631742.144645] _btrfs_ioctl_send+0x80/0x110 [btrfs]
[1631742.145161] ? trace_sched_stick_numa+0xe0/0xe0
[1631742.145685] btrfs_ioctl+0x13fe/0x3120 [btrfs]
[1631742.146179] ? account_entity_enqueue+0xd3/0x100
[1631742.146662] ? reweight_entity+0x154/0x1a0
[1631742.147135] ? update_curr+0x20/0x2a0
[1631742.147593] ? check_preempt_wakeup+0x103/0x250
[1631742.148053] ? do_vfs_ioctl+0xa2/0x6f0
[1631742.148510] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[1631742.148942] do_vfs_ioctl+0xa2/0x6f0
[1631742.149361] ? __fget+0x113/0x200
[1631742.149767] ksys_ioctl+0x70/0x80
[1631742.150159] __x64_sys_ioctl+0x16/0x20
[1631742.150543] do_syscall_64+0x60/0x1b0
[1631742.150931] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[1631742.151326] RIP: 0033:0x7f4cd9f5add7
(...)
[1631742.152509] RSP: 002b:00007ffe91017708 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[1631742.152892] RAX: ffffffffffffffda RBX: 0000000000000105 RCX: 00007f4cd9f5add7
[1631742.153268] RDX: 00007ffe91017790 RSI: 0000000040489426 RDI: 0000000000000007
[1631742.153633] RBP: 0000000000000007 R08: 00007f4cd9e79700 R09: 00007f4cd9e79700
[1631742.153999] R10: 00007f4cd9e799d0 R11: 0000000000000202 R12: 0000000000000003
[1631742.154365] R13: 0000555dfae53020 R14: 0000000000000000 R15: 0000000000000001
(...)
[1631742.156696] ---[ end trace 5dac9f96dcc3fd6b ]---
That BUG_ON happens because while send is using a node, that node is COWed
by a concurrent deduplication, gets freed and gets reused as a leaf (because
a transaction commit happened in between), so when it attempts to read a
slot from the extent buffer, at ctree.c:read_node_slot(), the extent buffer
contents were wiped out and it now matches a leaf (which can even belong to
some other tree now), hitting the BUG_ON(level == 0).
Fix this concurrency issue by not allowing send and deduplication to run
in parallel if both operate on the same readonly trees, returning EAGAIN
to user space and logging an exlicit warning in dmesg/syslog.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=be6821f82c3cc36e026f5afd10249988852b35ea
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6f2f0b394b54e2b159ef969a0b5274e9bbf82ff2
[3] https://lore.kernel.org/linux-btrfs/CAL3q7H7iqSEEyFaEtpRZw3cp613y+4k2Q8b4W7mweR3tZA05bQ@mail.gmail.com/
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-22 15:43:42 +00:00
|
|
|
/*
|
|
|
|
* Number of currently running deduplication operations that have a
|
|
|
|
* destination inode belonging to this root. Protected by the lock
|
|
|
|
* root_item_lock.
|
|
|
|
*/
|
|
|
|
int dedupe_in_progress;
|
2020-01-30 12:59:45 +00:00
|
|
|
/* For exclusion of snapshot creation and nocow writes */
|
|
|
|
struct btrfs_drew_lock snapshot_lock;
|
|
|
|
|
Btrfs: fix unexpected failure of nocow buffered writes after snapshotting when low on space
Commit e9894fd3e3b3 ("Btrfs: fix snapshot vs nocow writting") forced
nocow writes to fallback to COW, during writeback, when a snapshot is
created. This resulted in writes made before creating the snapshot to
unexpectedly fail with ENOSPC during writeback when success (0) was
returned to user space through the write system call.
The steps leading to this problem are:
1. When it's not possible to allocate data space for a write, the
buffered write path checks if a NOCOW write is possible. If it is,
it will not reserve space and success (0) is returned to user space.
2. Then when a snapshot is created, the root's will_be_snapshotted
atomic is incremented and writeback is triggered for all inode's that
belong to the root being snapshotted. Incrementing that atomic forces
all previous writes to fallback to COW during writeback (running
delalloc).
3. This results in the writeback for the inodes to fail and therefore
setting the ENOSPC error in their mappings, so that a subsequent
fsync on them will report the error to user space. So it's not a
completely silent data loss (since fsync will report ENOSPC) but it's
a very unexpected and undesirable behaviour, because if a clean
shutdown/unmount of the filesystem happens without previous calls to
fsync, it is expected to have the data present in the files after
mounting the filesystem again.
So fix this by adding a new atomic named snapshot_force_cow to the
root structure which prevents this behaviour and works the following way:
1. It is incremented when we start to create a snapshot after triggering
writeback and before waiting for writeback to finish.
2. This new atomic is now what is used by writeback (running delalloc)
to decide whether we need to fallback to COW or not. Because we
incremented this new atomic after triggering writeback in the
snapshot creation ioctl, we ensure that all buffered writes that
happened before snapshot creation will succeed and not fallback to
COW (which would make them fail with ENOSPC).
3. The existing atomic, will_be_snapshotted, is kept because it is used
to force new buffered writes, that start after we started
snapshotting, to reserve data space even when NOCOW is possible.
This makes these writes fail early with ENOSPC when there's no
available space to allocate, preventing the unexpected behaviour of
writeback later failing with ENOSPC due to a fallback to COW mode.
Fixes: e9894fd3e3b3 ("Btrfs: fix snapshot vs nocow writting")
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 02:30:30 +00:00
|
|
|
atomic_t snapshot_force_cow;
|
2017-12-12 07:34:34 +00:00
|
|
|
|
|
|
|
/* For qgroup metadata reserved space */
|
|
|
|
spinlock_t qgroup_meta_rsv_lock;
|
|
|
|
u64 qgroup_meta_rsv_pertrans;
|
|
|
|
u64 qgroup_meta_rsv_prealloc;
|
btrfs: qgroup: try to flush qgroup space when we get -EDQUOT
[PROBLEM]
There are known problem related to how btrfs handles qgroup reserved
space. One of the most obvious case is the the test case btrfs/153,
which do fallocate, then write into the preallocated range.
btrfs/153 1s ... - output mismatch (see xfstests-dev/results//btrfs/153.out.bad)
--- tests/btrfs/153.out 2019-10-22 15:18:14.068965341 +0800
+++ xfstests-dev/results//btrfs/153.out.bad 2020-07-01 20:24:40.730000089 +0800
@@ -1,2 +1,5 @@
QA output created by 153
+pwrite: Disk quota exceeded
+/mnt/scratch/testfile2: Disk quota exceeded
+/mnt/scratch/testfile2: Disk quota exceeded
Silence is golden
...
(Run 'diff -u xfstests-dev/tests/btrfs/153.out xfstests-dev/results//btrfs/153.out.bad' to see the entire diff)
[CAUSE]
Since commit c6887cd11149 ("Btrfs: don't do nocow check unless we have to"),
we always reserve space no matter if it's COW or not.
Such behavior change is mostly for performance, and reverting it is not
a good idea anyway.
For preallcoated extent, we reserve qgroup data space for it already,
and since we also reserve data space for qgroup at buffered write time,
it needs twice the space for us to write into preallocated space.
This leads to the -EDQUOT in buffered write routine.
And we can't follow the same solution, unlike data/meta space check,
qgroup reserved space is shared between data/metadata.
The EDQUOT can happen at the metadata reservation, so doing NODATACOW
check after qgroup reservation failure is not a solution.
[FIX]
To solve the problem, we don't return -EDQUOT directly, but every time
we got a -EDQUOT, we try to flush qgroup space:
- Flush all inodes of the root
NODATACOW writes will free the qgroup reserved at run_dealloc_range().
However we don't have the infrastructure to only flush NODATACOW
inodes, here we flush all inodes anyway.
- Wait for ordered extents
This would convert the preallocated metadata space into per-trans
metadata, which can be freed in later transaction commit.
- Commit transaction
This will free all per-trans metadata space.
Also we don't want to trigger flush multiple times, so here we introduce
a per-root wait list and a new root status, to ensure only one thread
starts the flushing.
Fixes: c6887cd11149 ("Btrfs: don't do nocow check unless we have to")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-13 10:50:48 +00:00
|
|
|
wait_queue_head_t qgroup_flush_wait;
|
2018-08-17 15:38:12 +00:00
|
|
|
|
Btrfs: prevent ioctls from interfering with a swap file
A later patch will implement swap file support for Btrfs, but before we
do that, we need to make sure that the various Btrfs ioctls cannot
change a swap file.
When a swap file is active, we must make sure that the extents of the
file are not moved and that they don't become shared. That means that
the following are not safe:
- chattr +c (enable compression)
- reflink
- dedupe
- snapshot
- defrag
Don't allow those to happen on an active swap file.
Additionally, balance, resize, device remove, and device replace are
also unsafe if they affect an active swapfile. Add a red-black tree of
block groups and devices which contain an active swapfile. Relocation
checks each block group against this tree and skips it or errors out for
balance or resize, respectively. Device remove and device replace check
the tree for the device they will operate on.
Note that we don't have to worry about chattr -C (disable nocow), which
we ignore for non-empty files, because an active swapfile must be
non-empty and can't be truncated. We also don't have to worry about
autodefrag because it's only done on COW files. Truncate and fallocate
are already taken care of by the generic code. Device add doesn't do
relocation so it's not an issue, either.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-11-03 17:28:12 +00:00
|
|
|
/* Number of active swapfiles */
|
|
|
|
atomic_t nr_swapfiles;
|
|
|
|
|
btrfs: qgroup: Introduce per-root swapped blocks infrastructure
To allow delayed subtree swap rescan, btrfs needs to record per-root
information about which tree blocks get swapped. This patch introduces
the required infrastructure.
The designed workflow will be:
1) Record the subtree root block that gets swapped.
During subtree swap:
O = Old tree blocks
N = New tree blocks
reloc tree subvolume tree X
Root Root
/ \ / \
NA OB OA OB
/ | | \ / | | \
NC ND OE OF OC OD OE OF
In this case, NA and OA are going to be swapped, record (NA, OA) into
subvolume tree X.
2) After subtree swap.
reloc tree subvolume tree X
Root Root
/ \ / \
OA OB NA OB
/ | | \ / | | \
OC OD OE OF NC ND OE OF
3a) COW happens for OB
If we are going to COW tree block OB, we check OB's bytenr against
tree X's swapped_blocks structure.
If it doesn't fit any, nothing will happen.
3b) COW happens for NA
Check NA's bytenr against tree X's swapped_blocks, and get a hit.
Then we do subtree scan on both subtrees OA and NA.
Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND).
Then no matter what we do to subvolume tree X, qgroup numbers will
still be correct.
Then NA's record gets removed from X's swapped_blocks.
4) Transaction commit
Any record in X's swapped_blocks gets removed, since there is no
modification to swapped subtrees, no need to trigger heavy qgroup
subtree rescan for them.
This will introduce 128 bytes overhead for each btrfs_root even qgroup
is not enabled. This is to reduce memory allocations and potential
failures.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-23 07:15:16 +00:00
|
|
|
/* Record pairs of swapped blocks for qgroup */
|
|
|
|
struct btrfs_qgroup_swapped_blocks swapped_blocks;
|
|
|
|
|
btrfs: fix corrupt log due to concurrent fsync of inodes with shared extents
When we have extents shared amongst different inodes in the same subvolume,
if we fsync them in parallel we can end up with checksum items in the log
tree that represent ranges which overlap.
For example, consider we have inodes A and B, both sharing an extent that
covers the logical range from X to X + 64KiB:
1) Task A starts an fsync on inode A;
2) Task B starts an fsync on inode B;
3) Task A calls btrfs_csum_file_blocks(), and the first search in the
log tree, through btrfs_lookup_csum(), returns -EFBIG because it
finds an existing checksum item that covers the range from X - 64KiB
to X;
4) Task A checks that the checksum item has not reached the maximum
possible size (MAX_CSUM_ITEMS) and then releases the search path
before it does another path search for insertion (through a direct
call to btrfs_search_slot());
5) As soon as task A releases the path and before it does the search
for insertion, task B calls btrfs_csum_file_blocks() and gets -EFBIG
too, because there is an existing checksum item that has an end
offset that matches the start offset (X) of the checksum range we want
to log;
6) Task B releases the path;
7) Task A does the path search for insertion (through btrfs_search_slot())
and then verifies that the checksum item that ends at offset X still
exists and extends its size to insert the checksums for the range from
X to X + 64KiB;
8) Task A releases the path and returns from btrfs_csum_file_blocks(),
having inserted the checksums into an existing checksum item that got
its size extended. At this point we have one checksum item in the log
tree that covers the logical range from X - 64KiB to X + 64KiB;
9) Task B now does a search for insertion using btrfs_search_slot() too,
but it finds that the previous checksum item no longer ends at the
offset X, it now ends at an of offset X + 64KiB, so it leaves that item
untouched.
Then it releases the path and calls btrfs_insert_empty_item()
that inserts a checksum item with a key offset corresponding to X and
a size for inserting a single checksum (4 bytes in case of crc32c).
Subsequent iterations end up extending this new checksum item so that
it contains the checksums for the range from X to X + 64KiB.
So after task B returns from btrfs_csum_file_blocks() we end up with
two checksum items in the log tree that have overlapping ranges, one
for the range from X - 64KiB to X + 64KiB, and another for the range
from X to X + 64KiB.
Having checksum items that represent ranges which overlap, regardless of
being in the log tree or in the chekcsums tree, can lead to problems where
checksums for a file range end up not being found. This type of problem
has happened a few times in the past and the following commits fixed them
and explain in detail why having checksum items with overlapping ranges is
problematic:
27b9a8122ff71a "Btrfs: fix csum tree corruption, duplicate and outdated checksums"
b84b8390d6009c "Btrfs: fix file read corruption after extent cloning and fsync"
40e046acbd2f36 "Btrfs: fix missing data checksums after replaying a log tree"
Since this specific instance of the problem can only happen when logging
inodes, because it is the only case where concurrent attempts to insert
checksums for the same range can happen, fix the issue by using an extent
io tree as a range lock to serialize checksum insertion during inode
logging.
This issue could often be reproduced by the test case generic/457 from
fstests. When it happens it produces the following trace:
BTRFS critical (device dm-0): corrupt leaf: root=18446744073709551610 block=30625792 slot=42, csum end range (15020032) goes beyond the start range (15015936) of the next csum item
BTRFS info (device dm-0): leaf 30625792 gen 7 total ptrs 49 free space 2402 owner 18446744073709551610
BTRFS info (device dm-0): refs 1 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 15884
item 0 key (18446744073709551606 128 13979648) itemoff 3991 itemsize 4
item 1 key (18446744073709551606 128 13983744) itemoff 3987 itemsize 4
item 2 key (18446744073709551606 128 13987840) itemoff 3983 itemsize 4
item 3 key (18446744073709551606 128 13991936) itemoff 3979 itemsize 4
item 4 key (18446744073709551606 128 13996032) itemoff 3975 itemsize 4
item 5 key (18446744073709551606 128 14000128) itemoff 3971 itemsize 4
(...)
BTRFS error (device dm-0): block=30625792 write time tree block corruption detected
------------[ cut here ]------------
WARNING: CPU: 1 PID: 15884 at fs/btrfs/disk-io.c:539 btree_csum_one_bio+0x268/0x2d0 [btrfs]
Modules linked in: btrfs dm_thin_pool ...
CPU: 1 PID: 15884 Comm: fsx Tainted: G W 5.6.0-rc7-btrfs-next-58 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btree_csum_one_bio+0x268/0x2d0 [btrfs]
Code: c7 c7 ...
RSP: 0018:ffffbb0109e6f8e0 EFLAGS: 00010296
RAX: 0000000000000000 RBX: ffffe1c0847b6080 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffffaa963988 RDI: 0000000000000001
RBP: ffff956a4f4d2000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000526 R11: 0000000000000000 R12: ffff956a5cd28bb0
R13: 0000000000000000 R14: ffff956a649c9388 R15: 000000011ed82000
FS: 00007fb419959e80(0000) GS:ffff956a7aa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000fe6d54 CR3: 0000000138696005 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
btree_submit_bio_hook+0x67/0xc0 [btrfs]
submit_one_bio+0x31/0x50 [btrfs]
btree_write_cache_pages+0x2db/0x4b0 [btrfs]
? __filemap_fdatawrite_range+0xb1/0x110
do_writepages+0x23/0x80
__filemap_fdatawrite_range+0xd2/0x110
btrfs_write_marked_extents+0x15e/0x180 [btrfs]
btrfs_sync_log+0x206/0x10a0 [btrfs]
? kmem_cache_free+0x315/0x3b0
? btrfs_log_inode+0x1e8/0xf90 [btrfs]
? __mutex_unlock_slowpath+0x45/0x2a0
? lockref_put_or_lock+0x9/0x30
? dput+0x2d/0x580
? dput+0xb5/0x580
? btrfs_sync_file+0x464/0x4d0 [btrfs]
btrfs_sync_file+0x464/0x4d0 [btrfs]
do_fsync+0x38/0x60
__x64_sys_fsync+0x10/0x20
do_syscall_64+0x5c/0x280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb41953a6d0
Code: 48 3d ...
RSP: 002b:00007ffcc86bd218 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007fb41953a6d0
RDX: 0000000000000009 RSI: 0000000000040000 RDI: 0000000000000003
RBP: 0000000000040000 R08: 0000000000000001 R09: 0000000000000009
R10: 0000000000000064 R11: 0000000000000246 R12: 0000556cf4b2c060
R13: 0000000000000100 R14: 0000000000000000 R15: 0000556cf322b420
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffffa96bdedf>] copy_process+0x74f/0x2020
softirqs last enabled at (0): [<ffffffffa96bdedf>] copy_process+0x74f/0x2020
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace d543fc76f5ad7fd8 ]---
In that trace the tree checker detected the overlapping checksum items at
the time when we triggered writeback for the log tree when syncing the
log.
Another trace that can happen is due to BUG_ON() when deleting checksum
items while logging an inode:
BTRFS critical (device dm-0): slot 81 key (18446744073709551606 128 13635584) new key (18446744073709551606 128 13635584)
BTRFS info (device dm-0): leaf 30949376 gen 7 total ptrs 98 free space 8527 owner 18446744073709551610
BTRFS info (device dm-0): refs 4 lock (w:1 r:0 bw:0 br:0 sw:1 sr:0) lock_owner 13473 current 13473
item 0 key (257 1 0) itemoff 16123 itemsize 160
inode generation 7 size 262144 mode 100600
item 1 key (257 12 256) itemoff 16103 itemsize 20
item 2 key (257 108 0) itemoff 16050 itemsize 53
extent data disk bytenr 13631488 nr 4096
extent data offset 0 nr 131072 ram 131072
(...)
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.c:3153!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
CPU: 1 PID: 13473 Comm: fsx Not tainted 5.6.0-rc7-btrfs-next-58 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btrfs_set_item_key_safe+0x1ea/0x270 [btrfs]
Code: 0f b6 ...
RSP: 0018:ffff95e3889179d0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000051 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffffb7763988 RDI: 0000000000000001
RBP: fffffffffffffff6 R08: 0000000000000000 R09: 0000000000000001
R10: 00000000000009ef R11: 0000000000000000 R12: ffff8912a8ba5a08
R13: ffff95e388917a06 R14: ffff89138dcf68c8 R15: ffff95e388917ace
FS: 00007fe587084e80(0000) GS:ffff8913baa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe587091000 CR3: 0000000126dac005 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
btrfs_del_csums+0x2f4/0x540 [btrfs]
copy_items+0x4b5/0x560 [btrfs]
btrfs_log_inode+0x910/0xf90 [btrfs]
btrfs_log_inode_parent+0x2a0/0xe40 [btrfs]
? dget_parent+0x5/0x370
btrfs_log_dentry_safe+0x4a/0x70 [btrfs]
btrfs_sync_file+0x42b/0x4d0 [btrfs]
__x64_sys_msync+0x199/0x200
do_syscall_64+0x5c/0x280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fe586c65760
Code: 00 f7 ...
RSP: 002b:00007ffe250f98b8 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 00000000000040e1 RCX: 00007fe586c65760
RDX: 0000000000000004 RSI: 0000000000006b51 RDI: 00007fe58708b000
RBP: 0000000000006a70 R08: 0000000000000003 R09: 00007fe58700cb61
R10: 0000000000000100 R11: 0000000000000246 R12: 00000000000000e1
R13: 00007fe58708b000 R14: 0000000000006b51 R15: 0000558de021a420
Modules linked in: dm_log_writes ...
---[ end trace c92a7f447a8515f5 ]---
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-18 11:14:50 +00:00
|
|
|
/* Used only by log trees, when logging csum items */
|
|
|
|
struct extent_io_tree log_csum_range;
|
|
|
|
|
btrfs: track data relocation with simple quota
Relocation data allocations are quite tricky for simple quotas. The
basic data relocation sequence is (ignoring details that aren't relevant
to this fix):
- create a fake relocation data fs root
- create a fake relocation inode in that root
- for each data extent:
- preallocate a data extent on behalf of the fake inode
- copy over the data
- for each extent
- swap the refs so that the original file extent now refers to the new
extent item
- drop the fake root, dropping its refs on the old extents, which lets
us delete them.
Done naively, this results in storing an extent item in the extent tree
whose owner_ref points at the relocation data root and a no-op squota
recording, since the reloc root is not a legit fstree. So far, that's
OK. The problem comes when you do the swap, and leave an extent item
owned by this bogus root as the real permanent extents of the file. If
the file then drops that ref, we free it and no-op account that against
the fake relocation root. Essentially, this means that relocation is
simple quota "extent laundering", since we re-own the extents into a
fake root.
Simple quotas very intentionally doesn't have a mechanism for
transferring ownership of extents, as that is exactly the complicated
thing we are trying to avoid with the new design. Further, it cannot be
correctly done in this case, since at the time you create the new
"real" refs, there is no way to know which was the original owner before
relocation unless we track it.
Therefore, it makes more sense to trick the preallocation to handle
relocation as a special case and note the proper owner ref from the
beginning. That way, we never write out an extent item without the
correct owner ref that it will eventually have.
This could be done by wiring a special root parameter all the way
through the allocation code path, but to avoid that special case
touching all the code, take advantage of the serial nature of relocation
to store the src root on the relocation root object. Then when we finish
the prealloc, if it happens to be this case, prepare the delayed ref
appropriately.
We must also add logic to handle relocating adjacent extents with
different owning roots. Those cannot be preallocated together in a
cluster as it would lose the separate ownership information.
This is obviously a smelly bit of code, but I think it is the best
solution to the problem, given the relocation implementation.
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-28 21:00:09 +00:00
|
|
|
/* Used in simple quotas, track root during relocation. */
|
|
|
|
u64 relocation_src_root;
|
|
|
|
|
2018-08-17 15:38:12 +00:00
|
|
|
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
|
|
|
|
u64 alloc_bytenr;
|
|
|
|
#endif
|
2020-01-24 14:33:00 +00:00
|
|
|
|
|
|
|
#ifdef CONFIG_BTRFS_DEBUG
|
|
|
|
struct list_head leak_list;
|
|
|
|
#endif
|
2007-03-15 16:56:47 +00:00
|
|
|
};
|
2017-05-22 10:16:11 +00:00
|
|
|
|
2022-11-15 16:16:10 +00:00
|
|
|
static inline bool btrfs_root_readonly(const struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
/* Byte-swap the constant at compile time, root_item::flags is LE */
|
|
|
|
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline bool btrfs_root_dead(const struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
/* Byte-swap the constant at compile time, root_item::flags is LE */
|
|
|
|
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline u64 btrfs_root_id(const struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
return root->root_key.objectid;
|
|
|
|
}
|
|
|
|
|
2023-10-04 10:38:49 +00:00
|
|
|
static inline int btrfs_get_root_log_transid(const struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
return READ_ONCE(root->log_transid);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_root_log_transid(struct btrfs_root *root, int log_transid)
|
|
|
|
{
|
|
|
|
WRITE_ONCE(root->log_transid, log_transid);
|
|
|
|
}
|
|
|
|
|
2023-10-04 10:38:48 +00:00
|
|
|
static inline int btrfs_get_root_last_log_commit(const struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
return READ_ONCE(root->last_log_commit);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_root_last_log_commit(struct btrfs_root *root, int commit_id)
|
|
|
|
{
|
|
|
|
WRITE_ONCE(root->last_log_commit, commit_id);
|
|
|
|
}
|
|
|
|
|
2020-09-08 10:27:22 +00:00
|
|
|
/*
|
|
|
|
* Structure that conveys information about an extent that is going to replace
|
|
|
|
* all the extents in a file range.
|
|
|
|
*/
|
|
|
|
struct btrfs_replace_extent_info {
|
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents
When cloning extents (or deduplicating) we create a transaction with a
space reservation that considers we will drop or update a single file
extent item of the destination inode (that we modify a single leaf). That
is fine for the vast majority of scenarios, however it might happen that
we need to drop many file extent items, and adjust at most two file extent
items, in the destination root, which can span multiple leafs. This will
lead to either the call to btrfs_drop_extents() to fail with ENOSPC or
the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode()
(called through clone_finish_inode_update()) to fail with ENOSPC. Such
failure results in a transaction abort, leaving the filesystem in a
read-only mode.
In order to fix this we need to follow the same approach as the hole
punching code, where we create a local reservation with 1 unit and keep
ending and starting transactions, after balancing the btree inode,
when __btrfs_drop_extents() returns ENOSPC. So fix this by making the
extent cloning call calls the recently added btrfs_punch_hole_range()
helper, which is what does the mentioned work for hole punching, and
make sure whenever we drop extent items in a transaction, we also add a
replacing file extent item, to avoid corruption (a hole) if after ending
a transaction and before starting a new one, the old transaction gets
committed and a power failure happens before we finish cloning.
A test case for fstests follows soon.
Reported-by: David Goodwin <david@codepoets.co.uk>
Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/
Reported-by: Sam Tygier <sam@tygier.co.uk>
Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/
Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 10:09:50 +00:00
|
|
|
u64 disk_offset;
|
|
|
|
u64 disk_len;
|
|
|
|
u64 data_offset;
|
|
|
|
u64 data_len;
|
|
|
|
u64 file_offset;
|
2020-09-08 10:27:21 +00:00
|
|
|
/* Pointer to a file extent item of type regular or prealloc. */
|
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents
When cloning extents (or deduplicating) we create a transaction with a
space reservation that considers we will drop or update a single file
extent item of the destination inode (that we modify a single leaf). That
is fine for the vast majority of scenarios, however it might happen that
we need to drop many file extent items, and adjust at most two file extent
items, in the destination root, which can span multiple leafs. This will
lead to either the call to btrfs_drop_extents() to fail with ENOSPC or
the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode()
(called through clone_finish_inode_update()) to fail with ENOSPC. Such
failure results in a transaction abort, leaving the filesystem in a
read-only mode.
In order to fix this we need to follow the same approach as the hole
punching code, where we create a local reservation with 1 unit and keep
ending and starting transactions, after balancing the btree inode,
when __btrfs_drop_extents() returns ENOSPC. So fix this by making the
extent cloning call calls the recently added btrfs_punch_hole_range()
helper, which is what does the mentioned work for hole punching, and
make sure whenever we drop extent items in a transaction, we also add a
replacing file extent item, to avoid corruption (a hole) if after ending
a transaction and before starting a new one, the old transaction gets
committed and a power failure happens before we finish cloning.
A test case for fstests follows soon.
Reported-by: David Goodwin <david@codepoets.co.uk>
Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/
Reported-by: Sam Tygier <sam@tygier.co.uk>
Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/
Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 10:09:50 +00:00
|
|
|
char *extent_buf;
|
btrfs: fix metadata reservation for fallocate that leads to transaction aborts
When doing an fallocate(), specially a zero range operation, we assume
that reserving 3 units of metadata space is enough, that at most we touch
one leaf in subvolume/fs tree for removing existing file extent items and
inserting a new file extent item. This assumption is generally true for
most common use cases. However when we end up needing to remove file extent
items from multiple leaves, we can end up failing with -ENOSPC and abort
the current transaction, turning the filesystem to RO mode. When this
happens a stack trace like the following is dumped in dmesg/syslog:
[ 1500.620934] ------------[ cut here ]------------
[ 1500.620938] BTRFS: Transaction aborted (error -28)
[ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs]
[ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...)
[ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1
[ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs]
[ 1500.621026] Code: 8b 40 50 f0 48 (...)
[ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286
[ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000
[ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff
[ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001
[ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000
[ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60
[ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000
[ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0
[ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1500.621049] Call Trace:
[ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs]
[ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs]
[ 1500.621108] vfs_fallocate+0x14d/0x290
[ 1500.621112] ksys_fallocate+0x3a/0x70
[ 1500.621117] __x64_sys_fallocate+0x1a/0x20
[ 1500.621120] do_syscall_64+0x33/0x80
[ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1500.621126] RIP: 0033:0x7fb5b248c477
[ 1500.621128] Code: 89 7c 24 08 (...)
[ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d
[ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477
[ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003
[ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000
[ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010
[ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003
[ 1500.621151] irq event stamp: 1026217
[ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0
[ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0
[ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606
[ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20
[ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]---
[ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left
When we use fallocate() internally, for reserving an extent for a space
cache, inode cache or relocation, we can't hit this problem since either
there aren't any file extent items to remove from the subvolume tree or
there is at most one.
When using plain fallocate() it's very unlikely, since that would require
having many file extent items representing holes for the target range and
crossing multiple leafs - we attempt to increase the range (merge) of such
file extent items when punching holes, so at most we end up with 2 file
extent items for holes at leaf boundaries.
However when using the zero range operation of fallocate() for a large
range (100+ MiB for example) that's fairly easy to trigger. The following
example reproducer triggers the issue:
$ cat reproducer.sh
#!/bin/bash
umount /dev/sdj &> /dev/null
mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null
mount /dev/sdj /mnt/sdj
# Create a 100M file with many file extent items. Punch a hole every 8K
# just to speedup the file creation - we could do 4K sequential writes
# followed by fsync (or O_SYNC) as well, but that takes a lot of time.
file_size=$((100 * 1024 * 1024))
xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar
for ((i = 0; i < $file_size; i += 8192)); do
xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar
done
# Force a transaction commit, so the zero range operation will be forced
# to COW all metadata extents it need to touch.
sync
xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar
umount /mnt/sdj
$ ./reproducer.sh
wrote 104857600/104857600 bytes at offset 0
100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec)
fallocate: No space left on device
$ dmesg
<shows the same stack trace pasted before>
To fix this use the existing infrastructure that hole punching and
extent cloning use for replacing a file range with another extent. This
deals with doing the removal of file extent items and inserting the new
one using an incremental approach, reserving more space when needed and
always ensuring we don't leave an implicit hole in the range in case
we need to do multiple iterations and a crash happens between iterations.
A test case for fstests will follow up soon.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 10:27:20 +00:00
|
|
|
/*
|
|
|
|
* Set to true when attempting to replace a file range with a new extent
|
|
|
|
* described by this structure, set to false when attempting to clone an
|
|
|
|
* existing extent into a file range.
|
|
|
|
*/
|
|
|
|
bool is_new_extent;
|
btrfs: add missing inode updates on each iteration when replacing extents
When replacing file extents, called during fallocate, hole punching,
clone and deduplication, we may not be able to replace/drop all the
target file extent items with a single transaction handle. We may get
-ENOSPC while doing it, in which case we release the transaction handle,
balance the dirty pages of the btree inode, flush delayed items and get
a new transaction handle to operate on what's left of the target range.
By dropping and replacing file extent items we have effectively modified
the inode, so we should bump its iversion and update its mtime/ctime
before we update the inode item. This is because if the transaction
we used for partially modifying the inode gets committed by someone after
we release it and before we finish the rest of the range, a power failure
happens, then after mounting the filesystem our inode has an outdated
iversion and mtime/ctime, corresponding to the values it had before we
changed it.
So add the missing iversion and mtime/ctime updates.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-06-06 09:41:18 +00:00
|
|
|
/* Indicate if we should update the inode's mtime and ctime. */
|
|
|
|
bool update_times;
|
btrfs: fix metadata reservation for fallocate that leads to transaction aborts
When doing an fallocate(), specially a zero range operation, we assume
that reserving 3 units of metadata space is enough, that at most we touch
one leaf in subvolume/fs tree for removing existing file extent items and
inserting a new file extent item. This assumption is generally true for
most common use cases. However when we end up needing to remove file extent
items from multiple leaves, we can end up failing with -ENOSPC and abort
the current transaction, turning the filesystem to RO mode. When this
happens a stack trace like the following is dumped in dmesg/syslog:
[ 1500.620934] ------------[ cut here ]------------
[ 1500.620938] BTRFS: Transaction aborted (error -28)
[ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs]
[ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...)
[ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1
[ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs]
[ 1500.621026] Code: 8b 40 50 f0 48 (...)
[ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286
[ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000
[ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff
[ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001
[ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000
[ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60
[ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000
[ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0
[ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1500.621049] Call Trace:
[ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs]
[ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs]
[ 1500.621108] vfs_fallocate+0x14d/0x290
[ 1500.621112] ksys_fallocate+0x3a/0x70
[ 1500.621117] __x64_sys_fallocate+0x1a/0x20
[ 1500.621120] do_syscall_64+0x33/0x80
[ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1500.621126] RIP: 0033:0x7fb5b248c477
[ 1500.621128] Code: 89 7c 24 08 (...)
[ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d
[ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477
[ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003
[ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000
[ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010
[ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003
[ 1500.621151] irq event stamp: 1026217
[ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0
[ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0
[ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606
[ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20
[ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]---
[ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left
When we use fallocate() internally, for reserving an extent for a space
cache, inode cache or relocation, we can't hit this problem since either
there aren't any file extent items to remove from the subvolume tree or
there is at most one.
When using plain fallocate() it's very unlikely, since that would require
having many file extent items representing holes for the target range and
crossing multiple leafs - we attempt to increase the range (merge) of such
file extent items when punching holes, so at most we end up with 2 file
extent items for holes at leaf boundaries.
However when using the zero range operation of fallocate() for a large
range (100+ MiB for example) that's fairly easy to trigger. The following
example reproducer triggers the issue:
$ cat reproducer.sh
#!/bin/bash
umount /dev/sdj &> /dev/null
mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null
mount /dev/sdj /mnt/sdj
# Create a 100M file with many file extent items. Punch a hole every 8K
# just to speedup the file creation - we could do 4K sequential writes
# followed by fsync (or O_SYNC) as well, but that takes a lot of time.
file_size=$((100 * 1024 * 1024))
xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar
for ((i = 0; i < $file_size; i += 8192)); do
xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar
done
# Force a transaction commit, so the zero range operation will be forced
# to COW all metadata extents it need to touch.
sync
xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar
umount /mnt/sdj
$ ./reproducer.sh
wrote 104857600/104857600 bytes at offset 0
100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec)
fallocate: No space left on device
$ dmesg
<shows the same stack trace pasted before>
To fix this use the existing infrastructure that hole punching and
extent cloning use for replacing a file range with another extent. This
deals with doing the removal of file extent items and inserting the new
one using an incremental approach, reserving more space when needed and
always ensuring we don't leave an implicit hole in the range in case
we need to do multiple iterations and a crash happens between iterations.
A test case for fstests will follow up soon.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-08 10:27:20 +00:00
|
|
|
/* Meaningful only if is_new_extent is true. */
|
|
|
|
int qgroup_reserved;
|
|
|
|
/*
|
|
|
|
* Meaningful only if is_new_extent is true.
|
|
|
|
* Used to track how many extent items we have already inserted in a
|
|
|
|
* subvolume tree that refer to the extent described by this structure,
|
|
|
|
* so that we know when to create a new delayed ref or update an existing
|
|
|
|
* one.
|
|
|
|
*/
|
|
|
|
int insertions;
|
Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents
When cloning extents (or deduplicating) we create a transaction with a
space reservation that considers we will drop or update a single file
extent item of the destination inode (that we modify a single leaf). That
is fine for the vast majority of scenarios, however it might happen that
we need to drop many file extent items, and adjust at most two file extent
items, in the destination root, which can span multiple leafs. This will
lead to either the call to btrfs_drop_extents() to fail with ENOSPC or
the subsequent calls to btrfs_insert_empty_item() or btrfs_update_inode()
(called through clone_finish_inode_update()) to fail with ENOSPC. Such
failure results in a transaction abort, leaving the filesystem in a
read-only mode.
In order to fix this we need to follow the same approach as the hole
punching code, where we create a local reservation with 1 unit and keep
ending and starting transactions, after balancing the btree inode,
when __btrfs_drop_extents() returns ENOSPC. So fix this by making the
extent cloning call calls the recently added btrfs_punch_hole_range()
helper, which is what does the mentioned work for hole punching, and
make sure whenever we drop extent items in a transaction, we also add a
replacing file extent item, to avoid corruption (a hole) if after ending
a transaction and before starting a new one, the old transaction gets
committed and a power failure happens before we finish cloning.
A test case for fstests follows soon.
Reported-by: David Goodwin <david@codepoets.co.uk>
Link: https://lore.kernel.org/linux-btrfs/a4a4cf31-9cf4-e52c-1f86-c62d336c9cd1@codepoets.co.uk/
Reported-by: Sam Tygier <sam@tygier.co.uk>
Link: https://lore.kernel.org/linux-btrfs/82aace9f-a1e3-1f0b-055f-3ea75f7a41a0@tygier.co.uk/
Fixes: b6f3409b2197e8f ("Btrfs: reserve sufficient space for ioctl clone")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-05 10:09:50 +00:00
|
|
|
};
|
|
|
|
|
2020-11-04 11:07:32 +00:00
|
|
|
/* Arguments for btrfs_drop_extents() */
|
|
|
|
struct btrfs_drop_extents_args {
|
|
|
|
/* Input parameters */
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If NULL, btrfs_drop_extents() will allocate and free its own path.
|
|
|
|
* If 'replace_extent' is true, this must not be NULL. Also the path
|
|
|
|
* is always released except if 'replace_extent' is true and
|
|
|
|
* btrfs_drop_extents() sets 'extent_inserted' to true, in which case
|
|
|
|
* the path is kept locked.
|
|
|
|
*/
|
|
|
|
struct btrfs_path *path;
|
|
|
|
/* Start offset of the range to drop extents from */
|
|
|
|
u64 start;
|
|
|
|
/* End (exclusive, last byte + 1) of the range to drop extents from */
|
|
|
|
u64 end;
|
|
|
|
/* If true drop all the extent maps in the range */
|
|
|
|
bool drop_cache;
|
|
|
|
/*
|
|
|
|
* If true it means we want to insert a new extent after dropping all
|
|
|
|
* the extents in the range. If this is true, the 'extent_item_size'
|
|
|
|
* parameter must be set as well and the 'extent_inserted' field will
|
|
|
|
* be set to true by btrfs_drop_extents() if it could insert the new
|
|
|
|
* extent.
|
|
|
|
* Note: when this is set to true the path must not be NULL.
|
|
|
|
*/
|
|
|
|
bool replace_extent;
|
|
|
|
/*
|
|
|
|
* Used if 'replace_extent' is true. Size of the file extent item to
|
|
|
|
* insert after dropping all existing extents in the range
|
|
|
|
*/
|
|
|
|
u32 extent_item_size;
|
|
|
|
|
|
|
|
/* Output parameters */
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Set to the minimum between the input parameter 'end' and the end
|
|
|
|
* (exclusive, last byte + 1) of the last dropped extent. This is always
|
|
|
|
* set even if btrfs_drop_extents() returns an error.
|
|
|
|
*/
|
|
|
|
u64 drop_end;
|
btrfs: update the number of bytes used by an inode atomically
There are several occasions where we do not update the inode's number of
used bytes atomically, resulting in a concurrent stat(2) syscall to report
a value of used blocks that does not correspond to a valid value, that is,
a value that does not match neither what we had before the operation nor
what we get after the operation completes.
In extreme cases it can result in stat(2) reporting zero used blocks, which
can cause problems for some userspace tools where they can consider a file
with a non-zero size and zero used blocks as completely sparse and skip
reading data, as reported/discussed a long time ago in some threads like
the following:
https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html
The cases where this can happen are the following:
-> Case 1
If we do a write (buffered or direct IO) against a file region for which
there is already an allocated extent (or multiple extents), then we have a
short time window where we can report a number of used blocks to stat(2)
that does not take into account the file region being overwritten. This
short time window happens when completing the ordered extent(s).
This happens because when we drop the extents in the write range we
decrement the inode's number of bytes and later on when we insert the new
extent(s) we increment the number of bytes in the inode, resulting in a
short time window where a stat(2) syscall can get an incorrect number of
used blocks.
If we do writes that overwrite an entire file, then we have a short time
window where we report 0 used blocks to stat(2).
Example reproducer:
$ cat reproducer-1.sh
#!/bin/bash
MNT=/mnt/sdi
DEV=/dev/sdi
stat_loop()
{
trap "wait; exit" SIGTERM
local filepath=$1
local expected=$2
local got
while :; do
got=$(stat -c %b $filepath)
if [ $got -ne $expected ]; then
echo -n "ERROR: unexpected used blocks"
echo " (got: $got expected: $expected)"
fi
done
}
mkfs.btrfs -f $DEV > /dev/null
# mkfs.xfs -f $DEV > /dev/null
# mkfs.ext4 -F $DEV > /dev/null
# mkfs.f2fs -f $DEV > /dev/null
# mkfs.reiserfs -f $DEV > /dev/null
mount $DEV $MNT
xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null
expected=$(stat -c %b $MNT/foobar)
# Create a process to keep calling stat(2) on the file and see if the
# reported number of blocks used (disk space used) changes, it should
# not because we are not increasing the file size nor punching holes.
stat_loop $MNT/foobar $expected &
loop_pid=$!
for ((i = 0; i < 50000; i++)); do
xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null
done
kill $loop_pid &> /dev/null
wait
umount $DEV
$ ./reproducer-1.sh
ERROR: unexpected used blocks (got: 0 expected: 128)
ERROR: unexpected used blocks (got: 0 expected: 128)
(...)
Note that since this is a short time window where the race can happen, the
reproducer may not be able to always trigger the bug in one run, or it may
trigger it multiple times.
-> Case 2
If we do a buffered write against a file region that does not have any
allocated extents, like a hole or beyond EOF, then during ordered extent
completion we have a short time window where a concurrent stat(2) syscall
can report a number of used blocks that does not correspond to the value
before or after the write operation, a value that is actually larger than
the value after the write completes.
This happens because once we start a buffered write into an unallocated
file range we increment the inode's 'new_delalloc_bytes', to make sure
any stat(2) call gets a correct used blocks value before delalloc is
flushed and completes. However at ordered extent completion, after we
inserted the new extent, we increment the inode's number of bytes used
with the size of the new extent, and only later, when clearing the range
in the inode's iotree, we decrement the inode's 'new_delalloc_bytes'
counter with the size of the extent. So this results in a short time
window where a concurrent stat(2) syscall can report a number of used
blocks that accounts for the new extent twice.
Example reproducer:
$ cat reproducer-2.sh
#!/bin/bash
MNT=/mnt/sdi
DEV=/dev/sdi
stat_loop()
{
trap "wait; exit" SIGTERM
local filepath=$1
local expected=$2
local got
while :; do
got=$(stat -c %b $filepath)
if [ $got -ne $expected ]; then
echo -n "ERROR: unexpected used blocks"
echo " (got: $got expected: $expected)"
fi
done
}
mkfs.btrfs -f $DEV > /dev/null
# mkfs.xfs -f $DEV > /dev/null
# mkfs.ext4 -F $DEV > /dev/null
# mkfs.f2fs -f $DEV > /dev/null
# mkfs.reiserfs -f $DEV > /dev/null
mount $DEV $MNT
touch $MNT/foobar
write_size=$((64 * 1024))
for ((i = 0; i < 16384; i++)); do
offset=$(($i * $write_size))
xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null
blocks_used=$(stat -c %b $MNT/foobar)
# Fsync the file to trigger writeback and keep calling stat(2) on it
# to see if the number of blocks used changes.
stat_loop $MNT/foobar $blocks_used &
loop_pid=$!
xfs_io -c "fsync" $MNT/foobar
kill $loop_pid &> /dev/null
wait $loop_pid
done
umount $DEV
$ ./reproducer-2.sh
ERROR: unexpected used blocks (got: 265472 expected: 265344)
ERROR: unexpected used blocks (got: 284032 expected: 283904)
(...)
Note that since this is a short time window where the race can happen, the
reproducer may not be able to always trigger the bug in one run, or it may
trigger it multiple times.
-> Case 3
Another case where such problems happen is during other operations that
replace extents in a file range with other extents. Those operations are
extent cloning, deduplication and fallocate's zero range operation.
The cause of the problem is similar to the first case. When we drop the
extents from a range, we decrement the inode's number of bytes, and later
on, after inserting the new extents we increment it. Since this is not
done atomically, a concurrent stat(2) call can see and return a number of
used blocks that is smaller than it should be, does not match the number
of used blocks before or after the clone/deduplication/zero operation.
Like for the first case, when doing a clone, deduplication or zero range
operation against an entire file, we end up having a time window where we
can report 0 used blocks to a stat(2) call.
Example reproducer:
$ cat reproducer-3.sh
#!/bin/bash
MNT=/mnt/sdi
DEV=/dev/sdi
mkfs.btrfs -f $DEV > /dev/null
# mkfs.xfs -f -m reflink=1 $DEV > /dev/null
mount $DEV $MNT
extent_size=$((64 * 1024))
num_extents=16384
file_size=$(($extent_size * $num_extents))
# File foo has many small extents.
xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \
> /dev/null
# File bar has much less extents and has exactly the same data as foo.
xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null
expected=$(stat -c %b $MNT/foo)
# Now deduplicate bar into foo. While the deduplication is in progres,
# the number of used blocks/file size reported by stat should not change
xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null &
dedupe_pid=$!
while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do
used=$(stat -c %b $MNT/foo)
if [ $used -ne $expected ]; then
echo "Unexpected blocks used: $used (expected: $expected)"
fi
done
umount $DEV
$ ./reproducer-3.sh
Unexpected blocks used: 2076800 (expected: 2097152)
Unexpected blocks used: 2097024 (expected: 2097152)
Unexpected blocks used: 2079872 (expected: 2097152)
(...)
Note that since this is a short time window where the race can happen, the
reproducer may not be able to always trigger the bug in one run, or it may
trigger it multiple times.
So fix this by:
1) Making btrfs_drop_extents() not decrement the VFS inode's number of
bytes, and instead return the number of bytes;
2) Making any code that drops extents and adds new extents update the
inode's number of bytes atomically, while holding the btrfs inode's
spinlock, which is also used by the stat(2) callback to get the inode's
number of bytes;
3) For ranges in the inode's iotree that are marked as 'delalloc new',
corresponding to previously unallocated ranges, increment the inode's
number of bytes when clearing the 'delalloc new' bit from the range,
in the same critical section that decrements the inode's
'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock.
An alternative would be to have btrfs_getattr() wait for any IO (ordered
extents in progress) and locking the whole range (0 to (u64)-1) while it
it computes the number of blocks used. But that would mean blocking
stat(2), which is a very used syscall and expected to be fast, waiting
for writes, clone/dedupe, fallocate, page reads, fiemap, etc.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 11:07:34 +00:00
|
|
|
/*
|
|
|
|
* The number of allocated bytes found in the range. This can be smaller
|
|
|
|
* than the range's length when there are holes in the range.
|
|
|
|
*/
|
|
|
|
u64 bytes_found;
|
2020-11-04 11:07:32 +00:00
|
|
|
/*
|
|
|
|
* Only set if 'replace_extent' is true. Set to true if we were able
|
|
|
|
* to insert a replacement extent after dropping all extents in the
|
|
|
|
* range, otherwise set to false by btrfs_drop_extents().
|
|
|
|
* Also, if btrfs_drop_extents() has set this to true it means it
|
|
|
|
* returned with the path locked, otherwise if it has set this to
|
|
|
|
* false it has returned with the path released.
|
|
|
|
*/
|
|
|
|
bool extent_inserted;
|
|
|
|
};
|
|
|
|
|
2017-07-24 19:14:25 +00:00
|
|
|
struct btrfs_file_private {
|
|
|
|
void *filldir_buf;
|
btrfs: fix infinite directory reads
The readdir implementation currently processes always up to the last index
it finds. This however can result in an infinite loop if the directory has
a large number of entries such that they won't all fit in the given buffer
passed to the readdir callback, that is, dir_emit() returns a non-zero
value. Because in that case readdir() will be called again and if in the
meanwhile new directory entries were added and we still can't put all the
remaining entries in the buffer, we keep repeating this over and over.
The following C program and test script reproduce the problem:
$ cat /mnt/readdir_prog.c
#include <sys/types.h>
#include <dirent.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
DIR *dir = opendir(".");
struct dirent *dd;
while ((dd = readdir(dir))) {
printf("%s\n", dd->d_name);
rename(dd->d_name, "TEMPFILE");
rename("TEMPFILE", dd->d_name);
}
closedir(dir);
}
$ gcc -o /mnt/readdir_prog /mnt/readdir_prog.c
$ cat test.sh
#!/bin/bash
DEV=/dev/sdi
MNT=/mnt/sdi
mkfs.btrfs -f $DEV &> /dev/null
#mkfs.xfs -f $DEV &> /dev/null
#mkfs.ext4 -F $DEV &> /dev/null
mount $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= 2000; i++)); do
echo -n > $MNT/testdir/file_$i
done
cd $MNT/testdir
/mnt/readdir_prog
cd /mnt
umount $MNT
This behaviour is surprising to applications and it's unlike ext4, xfs,
tmpfs, vfat and other filesystems, which always finish. In this case where
new entries were added due to renames, some file names may be reported
more than once, but this varies according to each filesystem - for example
ext4 never reported the same file more than once while xfs reports the
first 13 file names twice.
So change our readdir implementation to track the last index number when
opendir() is called and then make readdir() never process beyond that
index number. This gives the same behaviour as ext4.
Reported-by: Rob Landley <rob@landley.net>
Link: https://lore.kernel.org/linux-btrfs/2c8c55ec-04c6-e0dc-9c5c-8c7924778c35@landley.net/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217681
CC: stable@vger.kernel.org # 6.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-13 11:34:08 +00:00
|
|
|
u64 last_index;
|
btrfs: use cached state when looking for delalloc ranges with lseek
During lseek (SEEK_HOLE/DATA), whenever we find a hole or prealloc extent,
we will look for delalloc in that range, and one of the things we do for
that is to find out ranges in the inode's io_tree marked with
EXTENT_DELALLOC, using calls to count_range_bits().
Typically there's a single, or few, searches in the io_tree for delalloc
per lseek call. However it's common for applications to keep calling
lseek with SEEK_HOLE and SEEK_DATA to find where extents and holes are in
a file, read the extents and skip holes in order to avoid unnecessary IO
and save disk space by preserving holes.
One popular user is the cp utility from coreutils. Starting with coreutils
9.0, cp uses SEEK_HOLE and SEEK_DATA to iterate over the extents of a
file. Before 9.0, it used fiemap to figure out where holes and extents are
in the source file. Another popular user is the tar utility when used with
the --sparse / -S option to detect and preserve holes.
Given that the pattern is to keep calling lseek with a start offset that
matches the returned offset from the previous lseek call, we can benefit
from caching the last extent state visited in count_range_bits() and use
it for the next count_range_bits() from the next lseek call. Example,
the following strace excerpt from running tar:
$ strace tar cJSvf foo.tar.xz qemu_disk_file.raw
(...)
lseek(5, 125019574272, SEEK_HOLE) = 125024989184
lseek(5, 125024989184, SEEK_DATA) = 125024993280
lseek(5, 125024993280, SEEK_HOLE) = 125025239040
lseek(5, 125025239040, SEEK_DATA) = 125025255424
lseek(5, 125025255424, SEEK_HOLE) = 125025353728
lseek(5, 125025353728, SEEK_DATA) = 125025357824
lseek(5, 125025357824, SEEK_HOLE) = 125026766848
lseek(5, 125026766848, SEEK_DATA) = 125026770944
lseek(5, 125026770944, SEEK_HOLE) = 125027053568
(...)
Shows that pattern, which is the same as with cp from coreutils 9.0+.
So start using a cached state for the delalloc searches in lseek, and
store it in struct file's private data so that it can be reused across
lseek calls.
This change is part of a patchset that is comprised of the following
patches:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
The following test was run before and after applying the whole patchset:
$ cat test-cp.sh
#!/bin/bash
DEV=/dev/sdh
MNT=/mnt/sdh
# coreutils 8.32, cp uses fiemap to detect holes and extents
#CP_PROG=/usr/bin/cp
# coreutils 9.1, cp uses SEEK_HOLE/DATA to detect holes and extents
CP_PROG=/home/fdmanana/git/hub/coreutils/src/cp
umount $DEV &> /dev/null
mkfs.btrfs -f $DEV
mount $DEV $MNT
FILE_SIZE=$((1024 * 1024 * 1024))
echo "Creating file with a size of $((FILE_SIZE / 1024 / 1024))M"
# Create a very sparse file, where each extent has a length of 4K and
# is preceded by a 4K hole and followed by another 4K hole.
start=$(date +%s%N)
echo -n > $MNT/foobar
for ((off = 0; off < $FILE_SIZE; off += 8192)); do
xfs_io -c "pwrite -S 0xab $off 4K" $MNT/foobar > /dev/null
echo -ne "\r$off / $FILE_SIZE ..."
done
end=$(date +%s%N)
echo -e "\nFile created ($(( (end - start) / 1000000 )) milliseconds)"
start=$(date +%s%N)
$CP_PROG $MNT/foobar /dev/null
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "cp took $dur milliseconds with data/metadata cached and delalloc"
# Flush all delalloc.
sync
start=$(date +%s%N)
$CP_PROG $MNT/foobar /dev/null
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "cp took $dur milliseconds with data/metadata cached and no delalloc"
# Unmount and mount again to test the case without any metadata
# loaded in memory.
umount $MNT
mount $DEV $MNT
start=$(date +%s%N)
$CP_PROG $MNT/foobar /dev/null
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "cp took $dur milliseconds without data/metadata cached and no delalloc"
umount $MNT
The results, running on a box with a non-debug kernel (Debian's default
kernel config), were the following:
128M file, before patchset:
cp took 16574 milliseconds with data/metadata cached and delalloc
cp took 122 milliseconds with data/metadata cached and no delalloc
cp took 20144 milliseconds without data/metadata cached and no delalloc
128M file, after patchset:
cp took 6277 milliseconds with data/metadata cached and delalloc
cp took 109 milliseconds with data/metadata cached and no delalloc
cp took 210 milliseconds without data/metadata cached and no delalloc
512M file, before patchset:
cp took 14369 milliseconds with data/metadata cached and delalloc
cp took 429 milliseconds with data/metadata cached and no delalloc
cp took 88034 milliseconds without data/metadata cached and no delalloc
512M file, after patchset:
cp took 12106 milliseconds with data/metadata cached and delalloc
cp took 427 milliseconds with data/metadata cached and no delalloc
cp took 824 milliseconds without data/metadata cached and no delalloc
1G file, before patchset:
cp took 10074 milliseconds with data/metadata cached and delalloc
cp took 886 milliseconds with data/metadata cached and no delalloc
cp took 181261 milliseconds without data/metadata cached and no delalloc
1G file, after patchset:
cp took 3320 milliseconds with data/metadata cached and delalloc
cp took 880 milliseconds with data/metadata cached and no delalloc
cp took 1801 milliseconds without data/metadata cached and no delalloc
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-11 11:50:35 +00:00
|
|
|
struct extent_state *llseek_cached_state;
|
2017-07-24 19:14:25 +00:00
|
|
|
};
|
|
|
|
|
2016-06-15 13:22:56 +00:00
|
|
|
static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)
|
2016-06-15 14:33:06 +00:00
|
|
|
{
|
2017-05-22 10:16:11 +00:00
|
|
|
return info->nodesize - sizeof(struct btrfs_header);
|
2016-06-15 14:33:06 +00:00
|
|
|
}
|
|
|
|
|
2016-06-15 13:22:56 +00:00
|
|
|
static inline u32 BTRFS_MAX_ITEM_SIZE(const struct btrfs_fs_info *info)
|
2016-06-15 14:33:06 +00:00
|
|
|
{
|
2016-06-15 13:22:56 +00:00
|
|
|
return BTRFS_LEAF_DATA_SIZE(info) - sizeof(struct btrfs_item);
|
2016-06-15 14:33:06 +00:00
|
|
|
}
|
|
|
|
|
2016-06-15 13:22:56 +00:00
|
|
|
static inline u32 BTRFS_NODEPTRS_PER_BLOCK(const struct btrfs_fs_info *info)
|
2016-06-15 14:33:06 +00:00
|
|
|
{
|
2016-06-15 13:22:56 +00:00
|
|
|
return BTRFS_LEAF_DATA_SIZE(info) / sizeof(struct btrfs_key_ptr);
|
2016-06-15 14:33:06 +00:00
|
|
|
}
|
|
|
|
|
2016-06-15 13:22:56 +00:00
|
|
|
static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
|
2016-06-15 14:33:06 +00:00
|
|
|
{
|
2016-06-15 13:22:56 +00:00
|
|
|
return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
|
2016-06-15 14:33:06 +00:00
|
|
|
}
|
|
|
|
|
2016-01-21 10:25:53 +00:00
|
|
|
#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
|
2020-07-01 19:19:09 +00:00
|
|
|
((bytes) >> (fs_info)->sectorsize_bits)
|
2016-01-21 10:25:53 +00:00
|
|
|
|
2011-09-21 19:05:58 +00:00
|
|
|
static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
|
|
|
|
{
|
2015-11-07 00:28:49 +00:00
|
|
|
return mapping_gfp_constraint(mapping, ~__GFP_FS);
|
2011-09-21 19:05:58 +00:00
|
|
|
}
|
|
|
|
|
2024-01-12 18:06:16 +00:00
|
|
|
void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
|
2016-06-22 22:54:24 +00:00
|
|
|
int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
|
2014-12-08 14:01:12 +00:00
|
|
|
u64 num_bytes, u64 *actual_bytes);
|
2016-06-22 22:54:24 +00:00
|
|
|
int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);
|
2011-01-06 11:30:25 +00:00
|
|
|
|
2007-03-26 20:00:06 +00:00
|
|
|
/* ctree.c */
|
2022-09-14 15:06:38 +00:00
|
|
|
int __init btrfs_ctree_init(void);
|
|
|
|
void __cold btrfs_ctree_exit(void);
|
2023-02-08 17:46:48 +00:00
|
|
|
|
2023-02-24 03:31:26 +00:00
|
|
|
int btrfs_bin_search(struct extent_buffer *eb, int first_slot,
|
|
|
|
const struct btrfs_key *key, int *slot);
|
2023-02-08 17:46:48 +00:00
|
|
|
|
2019-10-01 17:57:39 +00:00
|
|
|
int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
|
2023-09-27 11:09:27 +00:00
|
|
|
|
|
|
|
#ifdef __LITTLE_ENDIAN
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Compare two keys, on little-endian the disk order is same as CPU order and
|
|
|
|
* we can avoid the conversion.
|
|
|
|
*/
|
|
|
|
static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk_key,
|
|
|
|
const struct btrfs_key *k2)
|
|
|
|
{
|
|
|
|
const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key;
|
|
|
|
|
|
|
|
return btrfs_comp_cpu_keys(k1, k2);
|
|
|
|
}
|
|
|
|
|
|
|
|
#else
|
|
|
|
|
|
|
|
/* Compare two keys in a memcmp fashion. */
|
|
|
|
static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk,
|
|
|
|
const struct btrfs_key *k2)
|
|
|
|
{
|
|
|
|
struct btrfs_key k1;
|
|
|
|
|
|
|
|
btrfs_disk_key_to_cpu(&k1, disk);
|
|
|
|
|
|
|
|
return btrfs_comp_cpu_keys(&k1, k2);
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
int btrfs_previous_item(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 min_objectid,
|
|
|
|
int type);
|
2014-01-12 13:38:33 +00:00
|
|
|
int btrfs_previous_extent_item(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 min_objectid);
|
2023-09-12 12:04:29 +00:00
|
|
|
void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
|
2014-11-12 04:43:09 +00:00
|
|
|
struct btrfs_path *path,
|
2017-01-18 07:24:37 +00:00
|
|
|
const struct btrfs_key *new_key);
|
2008-06-25 20:01:30 +00:00
|
|
|
struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
|
2008-06-25 20:01:31 +00:00
|
|
|
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
|
2008-06-25 20:01:31 +00:00
|
|
|
struct btrfs_key *key, int lowest_level,
|
2013-01-31 18:21:12 +00:00
|
|
|
u64 min_trans);
|
2008-06-25 20:01:31 +00:00
|
|
|
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
|
2013-01-31 18:21:12 +00:00
|
|
|
struct btrfs_path *path,
|
2008-06-25 20:01:31 +00:00
|
|
|
u64 min_trans);
|
2019-08-21 17:16:27 +00:00
|
|
|
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
|
|
|
|
int slot);
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
int btrfs_cow_block(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, struct extent_buffer *buf,
|
|
|
|
struct extent_buffer *parent, int parent_slot,
|
2020-08-20 15:46:03 +00:00
|
|
|
struct extent_buffer **cow_ret,
|
|
|
|
enum btrfs_lock_nesting nest);
|
2023-09-27 11:09:26 +00:00
|
|
|
int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf,
|
|
|
|
struct extent_buffer *parent, int parent_slot,
|
|
|
|
struct extent_buffer **cow_ret,
|
|
|
|
u64 search_start, u64 empty_size,
|
|
|
|
enum btrfs_lock_nesting nest);
|
2007-12-18 01:14:01 +00:00
|
|
|
int btrfs_copy_root(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf,
|
|
|
|
struct extent_buffer **cow_ret, u64 new_root_objectid);
|
2023-10-19 12:19:29 +00:00
|
|
|
bool btrfs_block_can_be_shared(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf);
|
2023-06-08 10:27:49 +00:00
|
|
|
int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, int level, int slot);
|
2023-09-12 12:04:29 +00:00
|
|
|
void btrfs_extend_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_path *path, u32 data_size);
|
|
|
|
void btrfs_truncate_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_path *path, u32 new_size, int from_end);
|
2008-12-10 14:10:46 +00:00
|
|
|
int btrfs_split_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
2017-01-18 07:24:37 +00:00
|
|
|
const struct btrfs_key *new_key,
|
2008-12-10 14:10:46 +00:00
|
|
|
unsigned long split_offset);
|
2009-11-12 09:33:58 +00:00
|
|
|
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
2017-01-18 07:24:37 +00:00
|
|
|
const struct btrfs_key *new_key);
|
2013-11-05 03:33:33 +00:00
|
|
|
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
|
|
|
|
u64 inum, u64 ioff, u8 key_type, struct btrfs_key *found_key);
|
2017-01-18 07:24:37 +00:00
|
|
|
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
const struct btrfs_key *key, struct btrfs_path *p,
|
|
|
|
int ins_len, int cow);
|
|
|
|
int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
|
2012-05-16 16:25:47 +00:00
|
|
|
struct btrfs_path *p, u64 time_seq);
|
2011-09-13 09:18:10 +00:00
|
|
|
int btrfs_search_slot_for_read(struct btrfs_root *root,
|
2017-01-18 07:24:37 +00:00
|
|
|
const struct btrfs_key *key,
|
|
|
|
struct btrfs_path *p, int find_higher,
|
|
|
|
int return_any);
|
2011-04-20 23:20:15 +00:00
|
|
|
void btrfs_release_path(struct btrfs_path *p);
|
2007-04-02 14:50:19 +00:00
|
|
|
struct btrfs_path *btrfs_alloc_path(void);
|
|
|
|
void btrfs_free_path(struct btrfs_path *p);
|
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
|
|
|
|
2008-01-29 20:11:36 +00:00
|
|
|
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, int slot, int nr);
|
|
|
|
static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path)
|
|
|
|
{
|
|
|
|
return btrfs_del_items(trans, root, path, path->slots[0], 1);
|
|
|
|
}
|
|
|
|
|
btrfs: loop only once over data sizes array when inserting an item batch
When inserting a batch of items into a btree, we end up looping over the
data sizes array 3 times:
1) Once in the caller of btrfs_insert_empty_items(), when it populates the
array with the data sizes for each item;
2) Once at btrfs_insert_empty_items() to sum the elements of the data
sizes array and compute the total data size;
3) And then once again at setup_items_for_insert(), where we do exactly
the same as what we do at btrfs_insert_empty_items(), to compute the
total data size.
That is not bad for small arrays, but when the arrays have hundreds of
elements, the time spent on looping is not negligible. For example when
doing batch inserts of delayed items for dir index items or when logging
a directory, it's common to have 200 to 260 dir index items in a single
batch when using a leaf size of 16K and using file names between 8 and 12
characters. For a 64K leaf size, multiply that by 4. Taking into account
that during directory logging or when flushing delayed dir index items we
can have many of those large batches, the time spent on the looping adds
up quickly.
It's also more important to avoid it at setup_items_for_insert(), since
we are holding a write lock on a leaf and, in some cases, on upper nodes
of the btree, which causes us to block other tasks that want to access
the leaf and nodes for longer than necessary.
So change the code so that setup_items_for_insert() and
btrfs_insert_empty_items() no longer compute the total data size, and
instead rely on the caller to supply it. This makes us loop over the
array only once, where we can both populate the data size array and
compute the total data size, taking advantage of spatial and temporal
locality. To make this more manageable, use a structure to contain
all the relevant details for a batch of items (keys array, data sizes
array, total data size, number of items), and use it as an argument
for btrfs_insert_empty_items() and setup_items_for_insert().
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 1/3 and performance results, and the specific tests, are
included in the changelog of patch 3/3.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-09-24 11:28:13 +00:00
|
|
|
/*
|
|
|
|
* Describes a batch of items to insert in a btree. This is used by
|
2021-09-24 11:28:14 +00:00
|
|
|
* btrfs_insert_empty_items().
|
btrfs: loop only once over data sizes array when inserting an item batch
When inserting a batch of items into a btree, we end up looping over the
data sizes array 3 times:
1) Once in the caller of btrfs_insert_empty_items(), when it populates the
array with the data sizes for each item;
2) Once at btrfs_insert_empty_items() to sum the elements of the data
sizes array and compute the total data size;
3) And then once again at setup_items_for_insert(), where we do exactly
the same as what we do at btrfs_insert_empty_items(), to compute the
total data size.
That is not bad for small arrays, but when the arrays have hundreds of
elements, the time spent on looping is not negligible. For example when
doing batch inserts of delayed items for dir index items or when logging
a directory, it's common to have 200 to 260 dir index items in a single
batch when using a leaf size of 16K and using file names between 8 and 12
characters. For a 64K leaf size, multiply that by 4. Taking into account
that during directory logging or when flushing delayed dir index items we
can have many of those large batches, the time spent on the looping adds
up quickly.
It's also more important to avoid it at setup_items_for_insert(), since
we are holding a write lock on a leaf and, in some cases, on upper nodes
of the btree, which causes us to block other tasks that want to access
the leaf and nodes for longer than necessary.
So change the code so that setup_items_for_insert() and
btrfs_insert_empty_items() no longer compute the total data size, and
instead rely on the caller to supply it. This makes us loop over the
array only once, where we can both populate the data size array and
compute the total data size, taking advantage of spatial and temporal
locality. To make this more manageable, use a structure to contain
all the relevant details for a batch of items (keys array, data sizes
array, total data size, number of items), and use it as an argument
for btrfs_insert_empty_items() and setup_items_for_insert().
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 1/3 and performance results, and the specific tests, are
included in the changelog of patch 3/3.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-09-24 11:28:13 +00:00
|
|
|
*/
|
|
|
|
struct btrfs_item_batch {
|
|
|
|
/*
|
|
|
|
* Pointer to an array containing the keys of the items to insert (in
|
|
|
|
* sorted order).
|
|
|
|
*/
|
|
|
|
const struct btrfs_key *keys;
|
|
|
|
/* Pointer to an array containing the data size for each item to insert. */
|
|
|
|
const u32 *data_sizes;
|
|
|
|
/*
|
|
|
|
* The sum of data sizes for all items. The caller can compute this while
|
|
|
|
* setting up the data_sizes array, so it ends up being more efficient
|
|
|
|
* than having btrfs_insert_empty_items() or setup_item_for_insert()
|
|
|
|
* doing it, as it would avoid an extra loop over a potentially large
|
|
|
|
* array, and in the case of setup_item_for_insert(), we would be doing
|
|
|
|
* it while holding a write lock on a leaf and often on upper level nodes
|
|
|
|
* too, unnecessarily increasing the size of a critical section.
|
|
|
|
*/
|
|
|
|
u32 total_data_size;
|
|
|
|
/* Size of the keys and data_sizes arrays (number of items in the batch). */
|
|
|
|
int nr;
|
|
|
|
};
|
|
|
|
|
2023-09-12 12:04:29 +00:00
|
|
|
void btrfs_setup_item_for_insert(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
2021-09-24 11:28:14 +00:00
|
|
|
struct btrfs_path *path,
|
|
|
|
const struct btrfs_key *key,
|
|
|
|
u32 data_size);
|
2017-01-18 07:24:37 +00:00
|
|
|
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
const struct btrfs_key *key, void *data, u32 data_size);
|
2008-01-29 20:15:18 +00:00
|
|
|
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
btrfs: loop only once over data sizes array when inserting an item batch
When inserting a batch of items into a btree, we end up looping over the
data sizes array 3 times:
1) Once in the caller of btrfs_insert_empty_items(), when it populates the
array with the data sizes for each item;
2) Once at btrfs_insert_empty_items() to sum the elements of the data
sizes array and compute the total data size;
3) And then once again at setup_items_for_insert(), where we do exactly
the same as what we do at btrfs_insert_empty_items(), to compute the
total data size.
That is not bad for small arrays, but when the arrays have hundreds of
elements, the time spent on looping is not negligible. For example when
doing batch inserts of delayed items for dir index items or when logging
a directory, it's common to have 200 to 260 dir index items in a single
batch when using a leaf size of 16K and using file names between 8 and 12
characters. For a 64K leaf size, multiply that by 4. Taking into account
that during directory logging or when flushing delayed dir index items we
can have many of those large batches, the time spent on the looping adds
up quickly.
It's also more important to avoid it at setup_items_for_insert(), since
we are holding a write lock on a leaf and, in some cases, on upper nodes
of the btree, which causes us to block other tasks that want to access
the leaf and nodes for longer than necessary.
So change the code so that setup_items_for_insert() and
btrfs_insert_empty_items() no longer compute the total data size, and
instead rely on the caller to supply it. This makes us loop over the
array only once, where we can both populate the data size array and
compute the total data size, taking advantage of spatial and temporal
locality. To make this more manageable, use a structure to contain
all the relevant details for a batch of items (keys array, data sizes
array, total data size, number of items), and use it as an argument
for btrfs_insert_empty_items() and setup_items_for_insert().
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 1/3 and performance results, and the specific tests, are
included in the changelog of patch 3/3.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-09-24 11:28:13 +00:00
|
|
|
const struct btrfs_item_batch *batch);
|
2008-01-29 20:15:18 +00:00
|
|
|
|
|
|
|
static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
2017-01-18 07:24:37 +00:00
|
|
|
const struct btrfs_key *key,
|
2008-01-29 20:15:18 +00:00
|
|
|
u32 data_size)
|
|
|
|
{
|
btrfs: loop only once over data sizes array when inserting an item batch
When inserting a batch of items into a btree, we end up looping over the
data sizes array 3 times:
1) Once in the caller of btrfs_insert_empty_items(), when it populates the
array with the data sizes for each item;
2) Once at btrfs_insert_empty_items() to sum the elements of the data
sizes array and compute the total data size;
3) And then once again at setup_items_for_insert(), where we do exactly
the same as what we do at btrfs_insert_empty_items(), to compute the
total data size.
That is not bad for small arrays, but when the arrays have hundreds of
elements, the time spent on looping is not negligible. For example when
doing batch inserts of delayed items for dir index items or when logging
a directory, it's common to have 200 to 260 dir index items in a single
batch when using a leaf size of 16K and using file names between 8 and 12
characters. For a 64K leaf size, multiply that by 4. Taking into account
that during directory logging or when flushing delayed dir index items we
can have many of those large batches, the time spent on the looping adds
up quickly.
It's also more important to avoid it at setup_items_for_insert(), since
we are holding a write lock on a leaf and, in some cases, on upper nodes
of the btree, which causes us to block other tasks that want to access
the leaf and nodes for longer than necessary.
So change the code so that setup_items_for_insert() and
btrfs_insert_empty_items() no longer compute the total data size, and
instead rely on the caller to supply it. This makes us loop over the
array only once, where we can both populate the data size array and
compute the total data size, taking advantage of spatial and temporal
locality. To make this more manageable, use a structure to contain
all the relevant details for a batch of items (keys array, data sizes
array, total data size, number of items), and use it as an argument
for btrfs_insert_empty_items() and setup_items_for_insert().
This patch is part of a small patchset that is comprised of the following
patches:
btrfs: loop only once over data sizes array when inserting an item batch
btrfs: unexport setup_items_for_insert()
btrfs: use single bulk copy operations when logging directories
This is patch 1/3 and performance results, and the specific tests, are
included in the changelog of patch 3/3.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-09-24 11:28:13 +00:00
|
|
|
struct btrfs_item_batch batch;
|
|
|
|
|
|
|
|
batch.keys = key;
|
|
|
|
batch.data_sizes = &data_size;
|
|
|
|
batch.total_data_size = data_size;
|
|
|
|
batch.nr = 1;
|
|
|
|
|
|
|
|
return btrfs_insert_empty_items(trans, root, path, &batch);
|
2008-01-29 20:15:18 +00:00
|
|
|
}
|
|
|
|
|
2012-06-11 06:29:29 +00:00
|
|
|
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
|
|
|
|
u64 time_seq);
|
2021-07-29 08:22:16 +00:00
|
|
|
|
|
|
|
int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key,
|
|
|
|
struct btrfs_path *path);
|
|
|
|
|
2022-03-09 13:50:38 +00:00
|
|
|
int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key,
|
|
|
|
struct btrfs_path *path);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Search in @root for a given @key, and store the slot found in @found_key.
|
|
|
|
*
|
|
|
|
* @root: The root node of the tree.
|
|
|
|
* @key: The key we are looking for.
|
|
|
|
* @found_key: Will hold the found item.
|
|
|
|
* @path: Holds the current slot/leaf.
|
|
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* @iter_ret: Contains the value returned from btrfs_search_slot or
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|
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* btrfs_get_next_valid_item, whichever was executed last.
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|
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*
|
|
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* The @iter_ret is an output variable that will contain the return value of
|
|
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* btrfs_search_slot, if it encountered an error, or the value returned from
|
|
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* btrfs_get_next_valid_item otherwise. That return value can be 0, if a valid
|
|
|
|
* slot was found, 1 if there were no more leaves, and <0 if there was an error.
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|
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|
*
|
|
|
|
* It's recommended to use a separate variable for iter_ret and then use it to
|
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|
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* set the function return value so there's no confusion of the 0/1/errno
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|
|
|
* values stemming from btrfs_search_slot.
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|
|
|
*/
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|
|
|
#define btrfs_for_each_slot(root, key, found_key, path, iter_ret) \
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|
|
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for (iter_ret = btrfs_search_slot(NULL, (root), (key), (path), 0, 0); \
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|
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(iter_ret) >= 0 && \
|
|
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(iter_ret = btrfs_get_next_valid_item((root), (found_key), (path))) == 0; \
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|
(path)->slots[0]++ \
|
|
|
|
)
|
|
|
|
|
2022-09-14 15:06:40 +00:00
|
|
|
int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq);
|
2021-07-26 12:15:12 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Search the tree again to find a leaf with greater keys.
|
|
|
|
*
|
|
|
|
* Returns 0 if it found something or 1 if there are no greater leaves.
|
|
|
|
* Returns < 0 on error.
|
|
|
|
*/
|
|
|
|
static inline int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
|
|
|
|
{
|
|
|
|
return btrfs_next_old_leaf(root, path, 0);
|
|
|
|
}
|
|
|
|
|
2012-06-19 13:42:25 +00:00
|
|
|
static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
|
|
|
|
{
|
|
|
|
return btrfs_next_old_item(root, p, 0);
|
|
|
|
}
|
2023-04-27 12:16:27 +00:00
|
|
|
int btrfs_leaf_free_space(const struct extent_buffer *leaf);
|
2013-05-14 10:20:43 +00:00
|
|
|
|
2012-05-29 15:06:54 +00:00
|
|
|
static inline int is_fstree(u64 rootid)
|
|
|
|
{
|
|
|
|
if (rootid == BTRFS_FS_TREE_OBJECTID ||
|
2015-02-27 08:24:23 +00:00
|
|
|
((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID &&
|
|
|
|
!btrfs_qgroup_level(rootid)))
|
2012-05-29 15:06:54 +00:00
|
|
|
return 1;
|
|
|
|
return 0;
|
|
|
|
}
|
2013-02-09 23:38:06 +00:00
|
|
|
|
2021-09-08 16:19:25 +00:00
|
|
|
static inline bool btrfs_is_data_reloc_root(const struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
return root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID;
|
|
|
|
}
|
|
|
|
|
2023-04-29 20:07:20 +00:00
|
|
|
u16 btrfs_csum_type_size(u16 type);
|
2022-11-15 16:16:14 +00:00
|
|
|
int btrfs_super_csum_size(const struct btrfs_super_block *s);
|
|
|
|
const char *btrfs_super_csum_name(u16 csum_type);
|
|
|
|
const char *btrfs_super_csum_driver(u16 csum_type);
|
|
|
|
size_t __attribute_const__ btrfs_get_num_csums(void);
|
|
|
|
|
2021-04-07 11:22:13 +00:00
|
|
|
/*
|
|
|
|
* We use page status Private2 to indicate there is an ordered extent with
|
|
|
|
* unfinished IO.
|
|
|
|
*
|
|
|
|
* Rename the Private2 accessors to Ordered, to improve readability.
|
|
|
|
*/
|
|
|
|
#define PageOrdered(page) PagePrivate2(page)
|
|
|
|
#define SetPageOrdered(page) SetPagePrivate2(page)
|
|
|
|
#define ClearPageOrdered(page) ClearPagePrivate2(page)
|
2022-02-09 20:21:39 +00:00
|
|
|
#define folio_test_ordered(folio) folio_test_private_2(folio)
|
|
|
|
#define folio_set_ordered(folio) folio_set_private_2(folio)
|
|
|
|
#define folio_clear_ordered(folio) folio_clear_private_2(folio)
|
2021-04-07 11:22:13 +00:00
|
|
|
|
2007-02-02 14:18:22 +00:00
|
|
|
#endif
|