We don't use the u_XX types anywhere, though they're defined.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove trivial comprator and open coded swap of two values.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's a simple forwarded call based on the operation that would better
fit the caller btrfs_map_block that's until now a trivial wrapper.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In doing my fsstress+EIO stress testing I started running into issues
where umount would get stuck forever because the uuid checker was
chewing through the thousands of subvolumes I had created.
We shouldn't block umount on this, simply bail if we're unmounting the
fs. We need to make sure we don't mark the UUID tree as ok, so we only
set that bit if we made it through the whole rescan operation, but
otherwise this is completely safe.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's used only during filesystem mount as such it can be made private to
disk-io.c file. Also use the occasion to move btrfs_uuid_rescan_kthread
as btrfs_check_uuid_tree is its sole caller.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_uuid_tree_iterate is called from only once place and its 2nd
argument is always btrfs_check_uuid_tree_entry. Simplify
btrfs_uuid_tree_iterate's signature by removing its 2nd argument and
directly calling btrfs_check_uuid_tree_entry. Also move the latter into
uuid-tree.h. No functional changes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Super-block reading in BTRFS is done using buffer_heads. Buffer_heads
have some drawbacks, like not being able to propagate errors from the
lower layers.
Directly use the page cache for reading the super blocks from disk or
invalidating an on-disk super block. We have to use the page cache so to
avoid races between mkfs and udev. See also 6f60cbd3ae ("btrfs: access
superblock via pagecache in scan_one_device").
This patch unwraps the buffer head API and does not change the way the
super block is actually read.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_scratch_superblocks() isn't used anywhere outside volumes.c so
remove it from the header file and mark it as static. Also move it
above it's callers so we don't need a forward declaration.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Block device mappings are never in highmem so kmap() / kunmap() calls for
pages from block devices are unneeded. Use page_address() instead of
kmap() to get to the virtual addreses.
While we're at it, read_cache_page_gfp() doesn't return NULL on error,
only an ERR_PTR, so use IS_ERR() to check for errors.
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Preparatory patch for removal of buffer_head usage in btrfs.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 668e48af7a ("btrfs: sysfs, add devid/dev_state kobject and
device attributes"), the functions btrfs_sysfs_add_device_link() and
btrfs_sysfs_rm_device_link() do more than just adding and removing the
device link as its name indicated. Rename them to be more specific
that's about the directory with the attirbutes
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are now using these for all roots, rename them to btrfs_put_root()
and btrfs_grab_root();
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all callers of btrfs_get_fs_root are subsequently calling
btrfs_grab_fs_root and handling dropping the ref when they are done
appropriately, go ahead and push btrfs_grab_fs_root up into
btrfs_get_fs_root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We lookup the uuid of arbitrary subvolumes, hold a ref on the root while
we're doing this.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All this does is call btrfs_get_fs_root() with check_ref == true. Just
use btrfs_get_fs_root() so we don't have a bunch of different helpers
that do the same thing.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Current code doesn't correctly handle the situation which arises when
a file system that has METADATA_UUID_INCOMPAT flag set and has its FSID
changed to the one in metadata uuid. This causes the incompat flag to
disappear.
In case of a power failure we could end up in a situation where part of
the disks in a multi-disk filesystem are correctly reverted to
METADATA_UUID_INCOMPAT flag unset state, while others have
METADATA_UUID_INCOMPAT set and CHANGING_FSID_V2_IN_PROGRESS.
This patch corrects the behavior required to handle the case where a
disk of the second type is scanned first, creating the necessary
btrfs_fs_devices. Subsequently, when a disk which has already completed
the transition is scanned it should overwrite the data in
btrfs_fs_devices.
Reported-by: Su Yue <Damenly_Su@gmx.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is one more cases which isn't handled by the original metadata
uuid work. Namely, when a filesystem has METADATA_UUID incompat bit and
the user decides to change the FSID to the original one e.g. have
metadata_uuid and fsid match. In case of power failure while this
operation is in progress we could end up in a situation where some of
the disks have the incompat bit removed and the other half have both
METADATA_UUID_INCOMPAT and FSID_CHANGING_IN_PROGRESS flags.
This patch handles the case where a disk that has successfully changed
its FSID such that it equals METADATA_UUID is scanned first.
Subsequently when a disk with both
METADATA_UUID_INCOMPAT/FSID_CHANGING_IN_PROGRESS flags is scanned
find_fsid_changed won't be able to find an appropriate btrfs_fs_devices.
This is done by extending find_fsid_changed to correctly find
btrfs_fs_devices whose metadata_uuid/fsid are the same and they match
the metadata_uuid of the currently scanned device.
Fixes: cc5de4e702 ("btrfs: Handle final split-brain possibility during fsid change")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reported-by: Su Yue <Damenly_Su@gmx.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
find_fsid became rather hairy with the introduction of metadata uuid
changing feature. Alleviate this by factoring out the metadata uuid
specific code in a dedicated function which deals with finding
correct fsid for a device with changed uuid.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Su Yue <Damenly_Su@gmx.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since find_fsid_inprogress should also handle the case in which an fs
didn't change its FSID make it call find_fsid directly. This makes the
code in device_list_add simpler by eliminating a conditional call of
find_fsid. No functional changes.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Su Yue <Damenly_Su@gmx.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's used only during initial block group reading to map physical
address of super block to a list of logical ones. Make it private to
block-group.c, add proper kernel doc and ensure it's exported only for
tests.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We had a report indicating that some read errors aren't reported by the
device stats in the userland. It is important to have the errors
reported in the device stat as user land scripts might depend on it to
take the reasonable corrective actions. But to debug these issue we need
to be really sure that request to reset the device stat did not come
from the userland itself. So log an info message when device error reset
happens.
For example:
BTRFS info (device sdc): device stats zeroed by btrfs(9223)
Reported-by: philip@philip-seeger.de
Link: https://www.spinics.net/lists/linux-btrfs/msg96528.html
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When discard is enabled, everytime a pinned extent is released back to
the block_group's free space cache, a discard is issued for the extent.
This is an overeager approach when it comes to discarding and helping
the SSD maintain enough free space to prevent severe garbage collection
situations.
This adds the beginning of async discard. Instead of issuing a discard
prior to returning it to the free space, it is just marked as untrimmed.
The block_group is then added to a LRU which then feeds into a workqueue
to issue discards at a much slower rate. Full discarding of unused block
groups is still done and will be addressed in a future patch of the
series.
For now, we don't persist the discard state of extents and bitmaps.
Therefore, our failure recovery mode will be to consider extents
untrimmed. This lets us handle failure and unmounting as one in the
same.
On a number of Facebook webservers, I collected data every minute
accounting the time we spent in btrfs_finish_extent_commit() (col. 1)
and in btrfs_commit_transaction() (col. 2). btrfs_finish_extent_commit()
is where we discard extents synchronously before returning them to the
free space cache.
discard=sync:
p99 total per minute p99 total per minute
Drive | extent_commit() (ms) | commit_trans() (ms)
---------------------------------------------------------------
Drive A | 434 | 1170
Drive B | 880 | 2330
Drive C | 2943 | 3920
Drive D | 4763 | 5701
discard=async:
p99 total per minute p99 total per minute
Drive | extent_commit() (ms) | commit_trans() (ms)
--------------------------------------------------------------
Drive A | 134 | 956
Drive B | 64 | 1972
Drive C | 59 | 1032
Drive D | 62 | 1200
While it's not great that the stats are cumulative over 1m, all of these
servers are running the same workload and and the delta between the two
are substantial. We are spending significantly less time in
btrfs_finish_extent_commit() which is responsible for discarding.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When closing a device, btrfs_close_one_device() first allocates a new
device, copies the device to close's name, replaces it in the dev_list
with the copy and then finally frees it.
This involves two memory allocation, which can potentially fail. As this
code path is tricky to unwind, the allocation failures where handled by
BUG_ON()s.
But this copying isn't strictly needed, all that is needed is resetting
the device in question to it's state it had after the allocation.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_close_one_device we're decrementing the number of open devices
before we're calling btrfs_close_bdev().
As there is no intermediate exit between these points in this function it
is technically OK to do so, but it makes the code a bit harder to understand.
Move both operations closer together and move the decrement step after
btrfs_close_bdev().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a user report, that cppcheck is complaining about a possible
NULL-pointer dereference in btrfs_destroy_dev_replace_tgtdev().
We're first dereferencing the 'tgtdev' variable and the later check for
the validity of the pointer with a WARN_ON(!tgtdev);
But all callers of btrfs_destroy_dev_replace_tgtdev() either explicitly
check if 'tgtdev' is non-NULL or directly allocate 'tgtdev', so the
WARN_ON() is impossible to hit. Just remove it to silence the checker's
complains.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205003
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The fstest btrfs/154 reports
[ 8675.381709] BTRFS: Transaction aborted (error -28)
[ 8675.383302] WARNING: CPU: 1 PID: 31900 at fs/btrfs/block-group.c:2038 btrfs_create_pending_block_groups+0x1e0/0x1f0 [btrfs]
[ 8675.390925] CPU: 1 PID: 31900 Comm: btrfs Not tainted 5.5.0-rc6-default+ #935
[ 8675.392780] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[ 8675.395452] RIP: 0010:btrfs_create_pending_block_groups+0x1e0/0x1f0 [btrfs]
[ 8675.402672] RSP: 0018:ffffb2090888fb00 EFLAGS: 00010286
[ 8675.404413] RAX: 0000000000000000 RBX: ffff92026dfa91c8 RCX: 0000000000000001
[ 8675.406609] RDX: 0000000000000000 RSI: ffffffff8e100899 RDI: ffffffff8e100971
[ 8675.408775] RBP: ffff920247c61660 R08: 0000000000000000 R09: 0000000000000000
[ 8675.410978] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffe4
[ 8675.412647] R13: ffff92026db74000 R14: ffff920247c616b8 R15: ffff92026dfbc000
[ 8675.413994] FS: 00007fd5e57248c0(0000) GS:ffff92027d800000(0000) knlGS:0000000000000000
[ 8675.416146] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8675.417833] CR2: 0000564aa51682d8 CR3: 000000006dcbc004 CR4: 0000000000160ee0
[ 8675.419801] Call Trace:
[ 8675.420742] btrfs_start_dirty_block_groups+0x355/0x480 [btrfs]
[ 8675.422600] btrfs_commit_transaction+0xc8/0xaf0 [btrfs]
[ 8675.424335] reset_balance_state+0x14a/0x190 [btrfs]
[ 8675.425824] btrfs_balance.cold+0xe7/0x154 [btrfs]
[ 8675.427313] ? kmem_cache_alloc_trace+0x235/0x2c0
[ 8675.428663] btrfs_ioctl_balance+0x298/0x350 [btrfs]
[ 8675.430285] btrfs_ioctl+0x466/0x2550 [btrfs]
[ 8675.431788] ? mem_cgroup_charge_statistics+0x51/0xf0
[ 8675.433487] ? mem_cgroup_commit_charge+0x56/0x400
[ 8675.435122] ? do_raw_spin_unlock+0x4b/0xc0
[ 8675.436618] ? _raw_spin_unlock+0x1f/0x30
[ 8675.438093] ? __handle_mm_fault+0x499/0x740
[ 8675.439619] ? do_vfs_ioctl+0x56e/0x770
[ 8675.441034] do_vfs_ioctl+0x56e/0x770
[ 8675.442411] ksys_ioctl+0x3a/0x70
[ 8675.443718] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 8675.445333] __x64_sys_ioctl+0x16/0x20
[ 8675.446705] do_syscall_64+0x50/0x210
[ 8675.448059] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 8675.479187] BTRFS: error (device vdb) in btrfs_create_pending_block_groups:2038: errno=-28 No space left
We now use btrfs_can_overcommit() to see if we can flip a block group
read only. Before this would fail because we weren't taking into
account the usable un-allocated space for allocating chunks. With my
patches we were allowed to do the balance, which is technically correct.
The test is trying to start balance on degraded mount. So now we're
trying to allocate a chunk and cannot because we want to allocate a
RAID1 chunk, but there's only 1 device that's available for usage. This
results in an ENOSPC.
But we shouldn't even be making it this far, we don't have enough
devices to restripe. The problem is we're using btrfs_num_devices(),
that also includes missing devices. That's not actually what we want, we
need to use rw_devices.
The chunk_mutex is not needed here, rw_devices changes only in device
add, remove or replace, all are excluded by EXCL_OP mechanism.
Fixes: e4d8ec0f65 ("Btrfs: implement online profile changing")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add stacktrace, update changelog, drop chunk_mutex ]
Signed-off-by: David Sterba <dsterba@suse.com>
The value 0 for devs_max means to spread the allocated chunks over all
available devices, eg. stripe for RAID0 or RAID5. This got mistakenly
copied to the RAID1C3/4 profiles. The intention is to have exactly 3 and
4 copies respectively.
Fixes: 47e6f7423b ("btrfs: add support for 3-copy replication (raid1c3)")
Fixes: 8d6fac0087 ("btrfs: add support for 4-copy replication (raid1c4)")
Signed-off-by: David Sterba <dsterba@suse.com>
struct btrfs_fs_devices::rotating currently is declared as an integer
variable but only used as a boolean.
Change the variable definition to bool and update to code touching it to
set 'true' and 'false'.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
struct btrfs_fs_devices::seeding currently is declared as an integer
variable but only used as a boolean.
Change the variable definition to bool and update to code touching it to
set 'true' and 'false'.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The type name is misleading, a single entry is named 'cache' while this
normally means a collection of objects. Rename that everywhere. Also the
identifier was quite long, making function prototypes harder to format.
Suggested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new raid1c3 and raid1c4 profiles are backward incompatible and the
name shall be 'raid1c34', the status can be found in the global
supported features in /sys/fs/btrfs/features or in the per-filesystem
directory.
Signed-off-by: David Sterba <dsterba@suse.com>
Add new block group profile to store 4 copies in a simliar way that
current RAID1 does. The profile attributes and constraints are defined
in the raid table and used by the same code that already handles the 2-
and 3-copy RAID1.
The minimum number of devices is 4, the maximum number of devices/chunks
that can be lost/damaged is 3. There is no comparable traditional RAID
level, the profile is added for future needs to accompany triple-parity
and beyond.
Signed-off-by: David Sterba <dsterba@suse.com>
Add new block group profile to store 3 copies in a simliar way that
current RAID1 does. The profile attributes and constraints are defined
in the raid table and used by the same code that already handles the
2-copy RAID1.
The minimum number of devices is 3, the maximum number of devices/chunks
that can be lost/damaged is 2. Like RAID6 but with 33% space
utilization.
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When deleting large files (which cross block group boundary) with
discard mount option, we find some btrfs_discard_extent() calls only
trimmed part of its space, not the whole range:
btrfs_discard_extent: type=0x1 start=19626196992 len=2144530432 trimmed=1073741824 ratio=50%
type: bbio->map_type, in above case, it's SINGLE DATA.
start: Logical address of this trim
len: Logical length of this trim
trimmed: Physically trimmed bytes
ratio: trimmed / len
Thus leaving some unused space not discarded.
[CAUSE]
When discard mount option is specified, after a transaction is fully
committed (super block written to disk), we begin to cleanup pinned
extents in the following call chain:
btrfs_commit_transaction()
|- btrfs_finish_extent_commit()
|- find_first_extent_bit(unpin, 0, &start, &end, EXTENT_DIRTY);
|- btrfs_discard_extent()
However, pinned extents are recorded in an extent_io_tree, which can
merge adjacent extent states.
When a large file gets deleted and it has adjacent file extents across
block group boundary, we will get a large merged range like this:
|<--- BG1 --->|<--- BG2 --->|
|//////|<-- Range to discard --->|/////|
To discard that range, we have the following calls:
btrfs_discard_extent()
|- btrfs_map_block()
| Returned bbio will end at BG1's end. As btrfs_map_block()
| never returns result across block group boundary.
|- btrfs_issuse_discard()
Issue discard for each stripe.
So we will only discard the range in BG1, not the remaining part in BG2.
Furthermore, this bug is not that reliably observed, for above case, if
there is no other extent in BG2, BG2 will be empty and btrfs will trim
all space of BG2, covering up the bug.
[FIX]
- Allow __btrfs_map_block_for_discard() to modify @length parameter
btrfs_map_block() uses its @length paramter to notify the caller how
many bytes are mapped in current call.
With __btrfs_map_block_for_discard() also modifing the @length,
btrfs_discard_extent() now understands when to do extra trim.
- Call btrfs_map_block() in a loop until we hit the range end Since we
now know how many bytes are mapped each time, we can iterate through
each block group boundary and issue correct trim for each range.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The old code goes:
offset = logical - em->start;
length = min_t(u64, em->len - offset, length);
Where @length calculation is dependent on offset, it can take reader
several more seconds to find it's just the same code as:
offset = logical - em->start;
length = min_t(u64, em->start + em->len - logical, length);
Use above code to make the length calculate independent from other
variable, thus slightly increase the readability.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
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>
The on-disk format of block group item makes use of the key that stores
the offset and length. This is further used in the code, although this
makes thing harder to understand. The key is also packed so the
offset/length is not properly aligned as u64.
Add start (key.objectid) and length (key.offset) members to block group
and remove the embedded key. When the item is searched or written, a
local variable for key is used.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For unknown reasons, the member 'used' in the block group struct is
stored in the b-tree item and accessed everywhere using the special
accessor helper. Let's unify it and make it a regular member and only
update the item before writing it to the tree.
The item is still being used for flags and chunk_objectid, there's some
duplication until the item is removed in following patches.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of checking if we've read a BTRFS_CHUNK_ITEM_KEY from disk and
then process it we could just bail out early if the read disk key wasn't
a BTRFS_CHUNK_ITEM_KEY.
This removes a level of indentation and makes the code nicer to read.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_may_alloc_data_chunk() we're checking if the chunk type is of
type BTRFS_BLOCK_GROUP_DATA and if it is we process it.
Instead of checking if the chunk type is a BTRFS_BLOCK_GROUP_DATA chunk
we can negate the check and bail out early if it isn't.
This makes the code a bit more readable.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we're not using btrfs_schedule_bio() anymore, delete all the
code that supported it.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_schedule_bio() hands IO off to a helper thread to do the actual
submit_bio() call. This has been used to make sure async crc and
compression helpers don't get stuck on IO submission. To maintain good
performance, over time the IO submission threads duplicated some IO
scheduler characteristics such as high and low priority IOs and they
also made some ugly assumptions about request allocation batch sizes.
All of this cost at least one extra context switch during IO submission,
and doesn't fit well with the modern blkmq IO stack. So, this commit stops
using btrfs_schedule_bio(). We may need to adjust the number of async
helper threads for crcs and compression, but long term it's a better
path.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For some reason the attribute is called __attribute_const__ and not
__const, marks functions that have no observable effects on program
state, IOW not reading pointers, just the arguments and calculating a
value. Allows the compiler to do some optimizations, based on
-Wsuggest-attribute=const . The effects are rather small, though, about
60 bytes decrese of btrfs.ko.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The attribute can mark functions supposed to be called rarely if at all
and the text can be moved to sections far from the other code. The
attribute has been added to several functions already, this patch is
based on hints given by gcc -Wsuggest-attribute=cold.
The net effect of this patch is decrease of btrfs.ko by 1000-1300,
depending on the config options.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Its very helpful if we had logged the device scanner process name to
debug the race condition between the systemd-udevd scan and the user
initiated device forget command.
This patch adds process name and pid to the scan message.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add pid to the message ]
Signed-off-by: David Sterba <dsterba@suse.com>
Replace is_power_of_2 with the helper that is self-documenting and
remove the open coded call in alloc_profile_is_valid.
Signed-off-by: David Sterba <dsterba@suse.com>
When balance reduces the number of copies of metadata, it reduces the
redundancy, use the term redundancy instead of integrity.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 9e0af23764 ("Btrfs: fix task hang under heavy compressed
write") worked around the issue that a recycled work item could get a
false dependency on the original work item due to how the workqueue code
guarantees non-reentrancy. It did so by giving different work functions
to different types of work.
However, the fixes in the previous few patches are more complete, as
they prevent a work item from being recycled at all (except for a tiny
window that the kernel workqueue code handles for us). This obsoletes
the previous fix, so we don't need the unique helpers for correctness.
The only other reason to keep them would be so they show up in stack
traces, but they always seem to be optimized to a tail call, so they
don't show up anyways. So, let's just get rid of the extra indirection.
While we're here, rename normal_work_helper() to the more informative
btrfs_work_helper().
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For SYSTEM chunks, despite the regular chunk item size limit, there is
another limit due to system chunk array size.
The extra limit was removed in a refactoring, so add it back.
Fixes: e3ecdb3fde ("btrfs: factor out devs_max setting in __btrfs_alloc_chunk")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, the command:
btrfs balance start -dconvert=single,soft .
on a Raspberry Pi produces the following kernel message:
BTRFS error (device mmcblk0p2): balance: invalid convert data profile single
This fails because we use is_power_of_2(unsigned long) to validate
the new data profile, the constant for 'single' profile uses bit 48,
and there are only 32 bits in a long on ARM.
Fix by open-coding the check using u64 variables.
Tested by completing the original balance command on several Raspberry
Pis.
Fixes: 818255feec ("btrfs: use common helper instead of open coding a bit test")
CC: stable@vger.kernel.org # 4.20+
Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
With v5.3 kernel, we can't convert to SINGLE profile:
# btrfs balance start -f -dconvert=single $mnt
ERROR: error during balancing '/mnt/btrfs': Invalid argument
# dmesg -t | tail
validate_convert_profile: data profile=0x1000000000000 allowed=0x20 is_valid=1 final=0x1000000000000 ret=1
BTRFS error (device dm-3): balance: invalid convert data profile single
[CAUSE]
With the extra debug output added, it shows that the @allowed bit is
lacking the special in-memory only SINGLE profile bit.
Thus we fail at that (profile & ~allowed) check.
This regression is caused by commit 081db89b13 ("btrfs: use raid_attr
to get allowed profiles for balance conversion") and the fact that we
don't use any bit to indicate SINGLE profile on-disk, but uses special
in-memory only bit to help distinguish different profiles.
[FIX]
Add that BTRFS_AVAIL_ALLOC_BIT_SINGLE to @allowed, so the code should be
the same as it was and fix the regression.
Reported-by: Chris Murphy <lists@colorremedies.com>
Fixes: 081db89b13 ("btrfs: use raid_attr to get allowed profiles for balance conversion")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The other dev stats functions are already there and the helpers are not
used by anything else.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Fix the fake ENOMEM return error code to the actual error in
clone_fs_devices().
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In a corrupted tree, if search for next devid finds the device with
devid = -1, then report the error -EUCLEAN back to the parent function
to fail gracefully.
The tree checker will not catch this in case the devids are created
using the following script:
umount /btrfs
dev1=/dev/sdb
dev2=/dev/sdc
mkfs.btrfs -fq -dsingle -msingle $dev1
mount $dev1 /btrfs
_fail()
{
echo $1
exit 1
}
while true; do
btrfs dev add -f $dev2 /btrfs || _fail "add failed"
btrfs dev del $dev1 /btrfs || _fail "del failed"
dev_tmp=$dev1
dev1=$dev2
dev2=$dev_tmp
done
With output:
BTRFS critical (device sdb): corrupt leaf: root=3 block=313739198464 slot=1 devid=1 invalid devid: has=507 expect=[0, 506]
BTRFS error (device sdb): block=313739198464 write time tree block corruption detected
BTRFS: error (device sdb) in btrfs_commit_transaction:2268: errno=-5 IO failure (Error while writing out transaction)
BTRFS warning (device sdb): Skipping commit of aborted transaction.
BTRFS: error (device sdb) in cleanup_transaction:1827: errno=-5 IO failure
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
[ add script and messages ]
Signed-off-by: David Sterba <dsterba@suse.com>
The btrfs_get_chunk_map() never returns NULL, it returns error pointers.
Fixes: 89b798ad1b ("btrfs: Use btrfs_get_io_geometry appropriately")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the function btrfs_init_dev_stats() goto out is not needed, because the
alloc has failed. So just return -ENOMEM.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
%found_key is not used, drop it since it hasn't been used since the
beginning in 733f4fbbc1 ("Btrfs: read device stats on mount, write
modified ones during commit").
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
__btrfs_reset_dev_stats() is a small helper function to reset devices stat
values, and is used only once, instead just open code it.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_dev_stat_reset() is an overdo in terms of wrapping. So this patch
open codes btrfs_dev_stat_reset().
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is prep work for moving all of the block group cache code into its
own file.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor comment updates ]
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Test case btrfs/156 fails since commit 302167c50b ("btrfs: don't end
the transaction for delayed refs in throttle") with ENOSPC.
[CAUSE]
The ENOSPC is reported from btrfs_can_relocate().
This function will check:
- If this block group is empty, we can relocate
- If we can enough free space, we can relocate
Above checks are valid but the following check is vague due to its
implementation:
- If and only if we can allocated a new block group to contain all the
used space, we can relocate
This design itself is OK, but the way to determine if we can allocate a
new block group is problematic.
btrfs_can_relocate() uses find_free_dev_extent() to find free space on a
device.
However find_free_dev_extent() only searches commit root and excludes
dev extents allocated in current trans, this makes it unable to use dev
extent just freed in current transaction.
So for the following example, btrfs_can_relocate() will report ENOSPC:
The example block group layout:
1M 129M 257M 385M 513M 550M
|///////|///////////|//////////| | |
// = Used bg, consider all bg is 100% used for easy calculation.
And all block groups are SINGLE, on-disk bytenr is the same as the
logical bytenr.
1) Bg in [129M, 257M) get relocated to [385M, 513M), transid=100
1M 129M 257M 385M 513M 550M
|///////| |//////////|/////////|
In transid 100, bg in [129M, 257M) get relocated to [385M, 513M)
However transid 100 is not committed yet, so in dev commit tree, we
still have the old dev extents layout:
1M 129M 257M 385M 513M 550M
|///////|///////////|//////////| | |
2) Try to relocate bg [257M, 385M)
We goes into btrfs_can_relocate(), no free space in current bgs, so we
check if we can find large enough free dev extents.
The first slot is [385M, 513M), but that is already used by new bg at
[385M, 513M), so we continue search.
The remaining slot is [512M, 550M), smaller than the bg's length 128M.
So btrfs_can_relocate report ENOSPC.
However this is over killed, in fact if we just skip btrfs_can_relocate()
check, and go into regular relocation routine, at extent reservation time,
if we can't find free extent, then we fallback to commit transaction,
which will free up the dev extents and allow new block group to be created.
[FIX]
The fix here is to remove btrfs_can_relocate() completely.
If we hit the false ENOSPC case just like btrfs/156, extent allocator
will push harder by committing transaction and we will have space for
new block group, avoiding the false ENOSPC.
If we really ran out of space, we will hit ENOSPC at
relocate_block_group(), and btrfs will just reports the ENOSPC error as
usual.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 6df9a95e63 ("Btrfs: make the chunk allocator completely
tree lockless") we search commit root of device tree to avoid deadlock.
This introduced a safety feature, find_free_dev_extent_start() won't
use dev extents which just get freed in current transaction.
This safety feature makes sure we won't allocate new block group using
just freed dev extents to break CoW.
However, this feature also makes find_free_dev_extent_start() not
reliable reporting free device space. Just add such comment to make
later viewer careful about this behavior.
This behavior makes one caller, btrfs_can_relocate() unreliable
determining the device free space.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function is only used locally in find_free_dev_extent(), no
external callers.
So unexport it.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes gcc '-Wunused-but-set-variable' warning:
fs/btrfs/volumes.c: In function __btrfs_map_block:
fs/btrfs/volumes.c:6023:6: warning:
variable offset set but not used [-Wunused-but-set-variable]
It is not used any more since commit 343abd1c0ca9 ("btrfs: Use
btrfs_get_io_geometry appropriately")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the 5.3 merge window, commit 7c7e301406 ("btrfs: sysfs: Replace
default_attrs in ktypes with groups"), we started using the member
"defaults_groups" for the kobject type "btrfs_raid_ktype". That leads
to a series of warnings when running some test cases of fstests, such
as btrfs/027, btrfs/124 and btrfs/176. The traces produced by those
warnings are like the following:
[116648.059212] kernfs: can not remove 'total_bytes', no directory
[116648.060112] WARNING: CPU: 3 PID: 28500 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x75/0x80
(...)
[116648.066482] CPU: 3 PID: 28500 Comm: umount Tainted: G W 5.3.0-rc3-btrfs-next-54 #1
(...)
[116648.069376] RIP: 0010:kernfs_remove_by_name_ns+0x75/0x80
(...)
[116648.072385] RSP: 0018:ffffabfd0090bd08 EFLAGS: 00010282
[116648.073437] RAX: 0000000000000000 RBX: ffffffffc0c11998 RCX: 0000000000000000
[116648.074201] RDX: ffff9fff603a7a00 RSI: ffff9fff603978a8 RDI: ffff9fff603978a8
[116648.074956] RBP: ffffffffc0b9ca2f R08: 0000000000000000 R09: 0000000000000001
[116648.075708] R10: ffff9ffe1f72e1c0 R11: 0000000000000000 R12: ffffffffc0b94120
[116648.076434] R13: ffffffffb3d9b4e0 R14: 0000000000000000 R15: dead000000000100
[116648.077143] FS: 00007f9cdc78a2c0(0000) GS:ffff9fff60380000(0000) knlGS:0000000000000000
[116648.077852] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[116648.078546] CR2: 00007f9fc4747ab4 CR3: 00000005c7832003 CR4: 00000000003606e0
[116648.079235] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[116648.079907] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[116648.080585] Call Trace:
[116648.081262] remove_files+0x31/0x70
[116648.081929] sysfs_remove_group+0x38/0x80
[116648.082596] sysfs_remove_groups+0x34/0x70
[116648.083258] kobject_del+0x20/0x60
[116648.083933] btrfs_free_block_groups+0x405/0x430 [btrfs]
[116648.084608] close_ctree+0x19a/0x380 [btrfs]
[116648.085278] generic_shutdown_super+0x6c/0x110
[116648.085951] kill_anon_super+0xe/0x30
[116648.086621] btrfs_kill_super+0x12/0xa0 [btrfs]
[116648.087289] deactivate_locked_super+0x3a/0x70
[116648.087956] cleanup_mnt+0xb4/0x160
[116648.088620] task_work_run+0x7e/0xc0
[116648.089285] exit_to_usermode_loop+0xfa/0x100
[116648.089933] do_syscall_64+0x1cb/0x220
[116648.090567] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[116648.091197] RIP: 0033:0x7f9cdc073b37
(...)
[116648.100046] ---[ end trace 22e24db328ccadf8 ]---
[116648.100618] ------------[ cut here ]------------
[116648.101175] kernfs: can not remove 'used_bytes', no directory
[116648.101731] WARNING: CPU: 3 PID: 28500 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x75/0x80
(...)
[116648.105649] CPU: 3 PID: 28500 Comm: umount Tainted: G W 5.3.0-rc3-btrfs-next-54 #1
(...)
[116648.107461] RIP: 0010:kernfs_remove_by_name_ns+0x75/0x80
(...)
[116648.109336] RSP: 0018:ffffabfd0090bd08 EFLAGS: 00010282
[116648.109979] RAX: 0000000000000000 RBX: ffffffffc0c119a0 RCX: 0000000000000000
[116648.110625] RDX: ffff9fff603a7a00 RSI: ffff9fff603978a8 RDI: ffff9fff603978a8
[116648.111283] RBP: ffffffffc0b9ca41 R08: 0000000000000000 R09: 0000000000000001
[116648.111940] R10: ffff9ffe1f72e1c0 R11: 0000000000000000 R12: ffffffffc0b94120
[116648.112603] R13: ffffffffb3d9b4e0 R14: 0000000000000000 R15: dead000000000100
[116648.113268] FS: 00007f9cdc78a2c0(0000) GS:ffff9fff60380000(0000) knlGS:0000000000000000
[116648.113939] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[116648.114607] CR2: 00007f9fc4747ab4 CR3: 00000005c7832003 CR4: 00000000003606e0
[116648.115286] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[116648.115966] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[116648.116649] Call Trace:
[116648.117326] remove_files+0x31/0x70
[116648.117997] sysfs_remove_group+0x38/0x80
[116648.118671] sysfs_remove_groups+0x34/0x70
[116648.119342] kobject_del+0x20/0x60
[116648.120022] btrfs_free_block_groups+0x405/0x430 [btrfs]
[116648.120707] close_ctree+0x19a/0x380 [btrfs]
[116648.121396] generic_shutdown_super+0x6c/0x110
[116648.122057] kill_anon_super+0xe/0x30
[116648.122702] btrfs_kill_super+0x12/0xa0 [btrfs]
[116648.123335] deactivate_locked_super+0x3a/0x70
[116648.123961] cleanup_mnt+0xb4/0x160
[116648.124586] task_work_run+0x7e/0xc0
[116648.125210] exit_to_usermode_loop+0xfa/0x100
[116648.125830] do_syscall_64+0x1cb/0x220
[116648.126463] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[116648.127080] RIP: 0033:0x7f9cdc073b37
(...)
[116648.135923] ---[ end trace 22e24db328ccadf9 ]---
These happen because, during the unmount path, we call kobject_del() for
raid kobjects that are not fully initialized, meaning that we set their
ktype (as btrfs_raid_ktype) through link_block_group() but we didn't set
their parent kobject, which is done through btrfs_add_raid_kobjects().
We have this split raid kobject setup since commit 75cb379d26
("btrfs: defer adding raid type kobject until after chunk relocation") in
order to avoid triggering reclaim during contextes where we can not
(either we are holding a transaction handle or some lock required by
the transaction commit path), so that we do the calls to kobject_add(),
which triggers GFP_KERNEL allocations, through btrfs_add_raid_kobjects()
in contextes where it is safe to trigger reclaim. That change expected
that a new raid kobject can only be created either when mounting the
filesystem or after raid profile conversion through the relocation path.
However, we can have new raid kobject created in other two cases at least:
1) During device replace (or scrub) after adding a device a to the
filesystem. The replace procedure (and scrub) do calls to
btrfs_inc_block_group_ro() which can allocate a new block group
with a new raid profile (because we now have more devices). This
can be triggered by test cases btrfs/027 and btrfs/176.
2) During a degraded mount trough any write path. This can be triggered
by test case btrfs/124.
Fixing this by adding extra calls to btrfs_add_raid_kobjects(), not only
makes things more complex and fragile, can also introduce deadlocks with
reclaim the following way:
1) Calling btrfs_add_raid_kobjects() at btrfs_inc_block_group_ro() or
anywhere in the replace/scrub path will cause a deadlock with reclaim
because if reclaim happens and a transaction commit is triggered,
the transaction commit path will block at btrfs_scrub_pause().
2) During degraded mounts it is essentially impossible to figure out where
to add extra calls to btrfs_add_raid_kobjects(), because allocation of
a block group with a new raid profile can happen anywhere, which means
we can't safely figure out which contextes are safe for reclaim, as
we can either hold a transaction handle or some lock needed by the
transaction commit path.
So it is too complex and error prone to have this split setup of raid
kobjects. So fix the issue by consolidating the setup of the kobjects in a
single place, at link_block_group(), and setup a nofs context there in
order to prevent reclaim being triggered by the memory allocations done
through the call chain of kobject_add().
Besides fixing the sysfs warnings during kobject_del(), this also ensures
the sysfs directories for the new raid profiles end up created and visible
to users (a bug that existed before the 5.3 commit 7c7e301406
("btrfs: sysfs: Replace default_attrs in ktypes with groups")).
Fixes: 75cb379d26 ("btrfs: defer adding raid type kobject until after chunk relocation")
Fixes: 7c7e301406 ("btrfs: sysfs: Replace default_attrs in ktypes with groups")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_get_io_geometry() calls btrfs_get_chunk_map() to acquire a reference
on a extent_map, but on normal operation it does not drop this reference
anymore.
This leads to excessive kmemleak reports.
Always call free_extent_map(), not just in the error case.
Fixes: 5f1411265e ("btrfs: Introduce btrfs_io_geometry infrastructure")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Migrate the struct definition and the one helper that's in ctree.h into
space-info.h
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Presently btrfs_map_block is used not only to do everything necessary to
map a bio to the underlying allocation profile but it's also used to
identify how much data could be written based on btrfs' stripe logic
without actually submitting anything. This is achieved by passing NULL
for 'bbio_ret' parameter.
This patch refactors all callers that require just the mapping length
by switching them to using btrfs_io_geometry instead of calling
btrfs_map_block with a special NULL value for 'bbio_ret'. No functional
change.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a structure that holds various parameters for IO calculations and a
helper that fills the values. This will help further refactoring and
reduction of functions that in some way open-coded the calculations.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Send always operates on read-only trees and always expected that while it
is in progress, nothing changes in those trees. Due to that expectation
and the fact that send is a read-only operation, it operates on commit
roots and does not hold transaction handles. However relocation can COW
nodes and leafs from read-only trees, which can cause unexpected failures
and crashes (hitting BUG_ONs). while send using a node/leaf, it gets
COWed, the transaction used to COW it is committed, a new transaction
starts, the extent previously used for that node/leaf gets allocated,
possibly for another tree, and the respective extent buffer' content
changes while send is still using it. When this happens send normally
fails with EIO being returned to user space and messages like the
following are found in dmesg/syslog:
[ 3408.699121] BTRFS error (device sdc): parent transid verify failed on 58703872 wanted 250 found 253
[ 3441.523123] BTRFS error (device sdc): did not find backref in send_root. inode=63211, offset=0, disk_byte=5222825984 found extent=5222825984
Other times, less often, we hit a BUG_ON() because an extent buffer that
send is using used to be a node, and while send is still using it, it
got COWed and got reused as a leaf while send is still using, producing
the following trace:
[ 3478.466280] ------------[ cut here ]------------
[ 3478.466282] kernel BUG at fs/btrfs/ctree.c:1806!
[ 3478.466965] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[ 3478.467635] CPU: 0 PID: 2165 Comm: btrfs Not tainted 5.0.0-btrfs-next-46 #1
[ 3478.468311] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[ 3478.469681] RIP: 0010:read_node_slot+0x122/0x130 [btrfs]
(...)
[ 3478.471758] RSP: 0018:ffffa437826bfaa0 EFLAGS: 00010246
[ 3478.472457] RAX: ffff961416ed7000 RBX: 000000000000003d RCX: 0000000000000002
[ 3478.473151] RDX: 000000000000003d RSI: ffff96141e387408 RDI: ffff961599b30000
[ 3478.473837] RBP: ffffa437826bfb8e R08: 0000000000000001 R09: ffffa437826bfb8e
[ 3478.474515] R10: ffffa437826bfa70 R11: 0000000000000000 R12: ffff9614385c8708
[ 3478.475186] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 3478.475840] FS: 00007f8e0e9cc8c0(0000) GS:ffff9615b6a00000(0000) knlGS:0000000000000000
[ 3478.476489] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3478.477127] CR2: 00007f98b67a056e CR3: 0000000005df6005 CR4: 00000000003606f0
[ 3478.477762] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3478.478385] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3478.479003] Call Trace:
[ 3478.479600] ? do_raw_spin_unlock+0x49/0xc0
[ 3478.480202] tree_advance+0x173/0x1d0 [btrfs]
[ 3478.480810] btrfs_compare_trees+0x30c/0x690 [btrfs]
[ 3478.481388] ? process_extent+0x1280/0x1280 [btrfs]
[ 3478.481954] btrfs_ioctl_send+0x1037/0x1270 [btrfs]
[ 3478.482510] _btrfs_ioctl_send+0x80/0x110 [btrfs]
[ 3478.483062] btrfs_ioctl+0x13fe/0x3120 [btrfs]
[ 3478.483581] ? rq_clock_task+0x2e/0x60
[ 3478.484086] ? wake_up_new_task+0x1f3/0x370
[ 3478.484582] ? do_vfs_ioctl+0xa2/0x6f0
[ 3478.485075] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[ 3478.485552] do_vfs_ioctl+0xa2/0x6f0
[ 3478.486016] ? __fget+0x113/0x200
[ 3478.486467] ksys_ioctl+0x70/0x80
[ 3478.486911] __x64_sys_ioctl+0x16/0x20
[ 3478.487337] do_syscall_64+0x60/0x1b0
[ 3478.487751] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 3478.488159] RIP: 0033:0x7f8e0d7d4dd7
(...)
[ 3478.489349] RSP: 002b:00007ffcf6fb4908 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[ 3478.489742] RAX: ffffffffffffffda RBX: 0000000000000105 RCX: 00007f8e0d7d4dd7
[ 3478.490142] RDX: 00007ffcf6fb4990 RSI: 0000000040489426 RDI: 0000000000000005
[ 3478.490548] RBP: 0000000000000005 R08: 00007f8e0d6f3700 R09: 00007f8e0d6f3700
[ 3478.490953] R10: 00007f8e0d6f39d0 R11: 0000000000000202 R12: 0000000000000005
[ 3478.491343] R13: 00005624e0780020 R14: 0000000000000000 R15: 0000000000000001
(...)
[ 3478.493352] ---[ end trace d5f537302be4f8c8 ]---
Another possibility, much less likely to happen, is that send will not
fail but the contents of the stream it produces may not be correct.
To avoid this, do not allow send and relocation (balance) to run in
parallel. In the long term the goal is to allow for both to be able to
run concurrently without any problems, but that will take a significant
effort in development and testing.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Preparatory patch for additional RAID1 profiles with more copies. The
mask will contain 3-copy and 4-copy, most of the checks for plain RAID1
work the same for the other profiles.
Signed-off-by: David Sterba <dsterba@suse.com>
The helper lacks the btrfs_ prefix and the parameter is the raw
blockgroup type, so none of the callers has to do the flags -> index
conversion.
Signed-off-by: David Sterba <dsterba@suse.com>
Factor the sequence of ifs to a helper, the 'data stripes' here means
the number of stripes without redundancy and parity.
Signed-off-by: David Sterba <dsterba@suse.com>
Replace open coded list of the profiles by selecting them from the
raid_attr table. The criteria are now more explicit, we need profiles
that have more than 1 copy of the data or can reconstruct the data with
a missing device.
Signed-off-by: David Sterba <dsterba@suse.com>
Iterate over the table and gather all allowed profiles for a given
number of devices, instead of open coding.
Signed-off-by: David Sterba <dsterba@suse.com>
fs_info::mapping_tree is the physical<->logical mapping tree and uses
the same underlying structure as extents, but is embedded to another
structure. There are no other members and this indirection is useless.
No functional change.
Signed-off-by: David Sterba <dsterba@suse.com>
The minimum number of devices for RAID5 is 2, though this is only a bit
expensive RAID1, and for RAID6 it's 3, which is a triple copy that works
only 3 devices.
mkfs.btrfs allows that and mounting such filesystem also works, so the
conversion via balance filters is inconsistent with the others and we
should not prevent it.
Signed-off-by: David Sterba <dsterba@suse.com>
The list of profiles in btrfs_chunk_max_errors lists DUP as a profile
DUP able to tolerate 1 device missing. Though this profile is special
with 2 copies, it still needs the device, unlike the others.
Looking at the history of changes, thre's no clear reason why DUP is
there, functions were refactored and blocks of code merged to one
helper.
d20983b40e Btrfs: fix writing data into the seed filesystem
- factor code to a helper
de11cc12df Btrfs: don't pre-allocate btrfs bio
- unrelated change, DUP still in the list with max errors 1
a236aed14c Btrfs: Deal with failed writes in mirrored configurations
- introduced the max errors, leaves DUP and RAID1 in the same group
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is used in more than one places so let's factor it out in ctree.h.
No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that these functions no longer require a handle to transaction to
inspect pending/pinned chunks the argument can be removed. At the same
time also remove any surrounding code which acquired the handle.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The pending chunks list contains chunks that are allocated in the
current transaction but haven't been created yet. The pinned chunks
list contains chunks that are being released in the current transaction.
Both describe chunks that are not reflected on disk as in use but are
unavailable just the same.
The pending chunks list is anchored by the transaction handle, which
means that we need to hold a reference to a transaction when working
with the list.
The way we use them is by iterating over both lists to perform
comparisons on the stripes they describe for each device. This is
backwards and requires that we keep a transaction handle open while
we're trimming.
This patchset adds an extent_io_tree to btrfs_device that maintains
the allocation state of the device. Extents are set dirty when
chunks are first allocated -- when the extent maps are added to the
mapping tree. They're cleared when last removed -- when the extent
maps are removed from the mapping tree. This matches the lifespan
of the pending and pinned chunks list and allows us to do trims
on unallocated space safely without pinning the transaction for what
may be a lengthy operation. We can also use this io tree to mark
which chunks have already been trimmed so we don't repeat the operation.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_device structs are freed from RCU context since device iteration
is protected by RCU. Currently this is achieved by using call_rcu since
no blocking functions are called within btrfs_free_device. Future
refactoring of pending/pinned chunks will require calling sleeping
functions.
This patch is in preparation for these changes by simply switching from
RCU callbacks to explicit calls of synchronize_rcu and calling
btrfs_free_device directly. This is functionally equivalent, making sure
that there are no readers at that time.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Chunks read from disk currently don't get their ->orig_block_len member
set, in contrast when a new chunk is allocated, the respective
extent_map's ->orig_block_len is assigned the size of the stripe of this
chunk.
Let's apply the same strategy for chunks which are read from
disk, not only does this codify the invariant that ->orig_block_len
always contains the size of the stripe for a chunk (when the em belongs
to the mapping tree). But it's also a preparatory patch for further work
around tracking chunk allocation in an extent tree rather than
pinned/pending lists.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During device shrink pinned/pending chunks (i.e. those which have been
deleted/created respectively, in the current transaction and haven't
touched disk) need to be accounted when doing device shrink. Presently
this happens after the main relocation loop in btrfs_shrink_device,
which could lead to making another go in the body of the function.
Since there is no hard requirement to perform pinned/pending chunks
handling after the relocation loop, move the code before it. This leads
to simplifying the code flow around - i.e. no need to use 'goto again'.
A notable side effect of this change is that modification of the
device's size requires a transaction to be started and committed before
the relocation loop starts. This is necessary to ensure that relocation
process sees the shrunk device size.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We currently overload the pending_chunks list to handle updating
btrfs_device->commit_bytes used. We don't actually care about the
extent mapping or even the device mapping for the chunk - we just need
the device, and we can end up processing it multiple times. The
fs_devices->resized_list does more or less the same thing, but with the
disk size. They are called consecutively during commit and have more or
less the same purpose.
We can combine the two lists into a single list that attaches to the
transaction and contains a list of devices that need updating. Since we
always add the device to a list when we change bytes_used or
disk_total_size, there's no harm in copying both values at once.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
For fuzzed image whose DEV_ITEM has invalid total_bytes as 0, then
kernel will just panic:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
#PF error: [normal kernel read fault]
PGD 800000022b2bd067 P4D 800000022b2bd067 PUD 22b2bc067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 1106 Comm: mount Not tainted 5.0.0-rc8+ #9
RIP: 0010:btrfs_verify_dev_extents+0x2a5/0x5a0
Call Trace:
open_ctree+0x160d/0x2149
btrfs_mount_root+0x5b2/0x680
[CAUSE]
If device extent verification finds a deivce with 0 total_bytes, then it
assumes it's a seed dummy, then search for seed devices.
But in this case, there is no seed device at all, causing NULL pointer.
[FIX]
Since this is caused by fuzzed image, let's go the tree-check way, just
add a new verification for device item.
Reported-by: Yoon Jungyeon <jungyeon@gatech.edu>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202691
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we have btrfs_check_chunk_valid() in tree-checker, let's do
chunk item verification in tree-checker too.
Since the tree-checker is run at endio time, if one chunk leaf fails
chunk verification, we can still retry the other copy, making btrfs more
robust to fuzzed image as we may still get a good chunk item.
Also since we have done chunk verification in tree block read time, skip
the btrfs_check_chunk_valid() call in read_one_chunk() if we're reading
chunk items from leaf.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
By function, chunk item verification is more suitable to be done inside
tree-checker.
So move btrfs_check_chunk_valid() to tree-checker.c and export it.
And since it's now moved to tree-checker, also add a better comment for
what this function is doing.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
BUG_ON(1) leads to bogus warnings from clang when
CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
fs/btrfs/volumes.c:5041:3: error: variable 'max_chunk_size' is used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
BUG_ON(1);
^~~~~~~~~
include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON'
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
^~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
# define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/btrfs/volumes.c:5046:9: note: uninitialized use occurs here
max_chunk_size);
^~~~~~~~~~~~~~
include/linux/kernel.h:860:36: note: expanded from macro 'min'
#define min(x, y) __careful_cmp(x, y, <)
^
include/linux/kernel.h:853:17: note: expanded from macro '__careful_cmp'
__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
^
include/linux/kernel.h:847:25: note: expanded from macro '__cmp_once'
typeof(y) unique_y = (y); \
^
fs/btrfs/volumes.c:5041:3: note: remove the 'if' if its condition is always true
BUG_ON(1);
^
include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON'
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
^
fs/btrfs/volumes.c:4993:20: note: initialize the variable 'max_chunk_size' to silence this warning
u64 max_chunk_size;
^
= 0
Change it to BUG() so clang can see that this code path can never
continue.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Sterba <dsterba@suse.com>
As readahead is an optimization, all errors are usually filtered out,
but still properly handled when the real read call is done. The commit
5e9d398240 ("btrfs: readpages() should submit IO as read-ahead") added
REQ_RAHEAD to readpages() because that's only used for readahead
(despite what one would expect from the callback name).
This causes a flood of messages and inflated read error stats, so skip
reporting in case it's readahead.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202403
Reported-by: LimeTech <tomm@lime-technology.com>
Fixes: 5e9d398240 ("btrfs: readpages() should submit IO as read-ahead")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: David Sterba <dsterba@suse.com>
We recently had a customer issue with a corrupted filesystem. When
trying to mount this image btrfs panicked with a division by zero in
calc_stripe_length().
The corrupt chunk had a 'num_stripes' value of 1. calc_stripe_length()
takes this value and divides it by the number of copies the RAID profile
is expected to have to calculate the amount of data stripes. As a DUP
profile is expected to have 2 copies this division resulted in 1/2 = 0.
Later then the 'data_stripes' variable is used as a divisor in the
stripe length calculation which results in a division by 0 and thus a
kernel panic.
When encountering a filesystem with a DUP block group and a
'num_stripes' value unequal to 2, refuse mounting as the image is
corrupted and will lead to unexpected behaviour.
Code inspection showed a RAID1 block group has the same issues.
Fixes: e06cd3dd7c ("Btrfs: add validadtion checks for chunk loading")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have killed volume mutex (commit: dccdb07bc9
btrfs: kill btrfs_fs_info::volume_mutex). This a trival one seems to have
escaped.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Support for a new command that can be used eg. as a command
$ btrfs device scan --forget [dev]'
(the final name may change though)
to undo the effects of 'btrfs device scan [dev]'. For this purpose
this patch proposes to use ioctl #5 as it was empty and is next to the
SCAN ioctl.
The new ioctl BTRFS_IOC_FORGET_DEV works only on the control device
(/dev/btrfs-control) to unregister one or all devices, devices that are
not mounted.
The argument is struct btrfs_ioctl_vol_args, ::name specifies the device
path. To unregister all device, the path is an empty string.
Again, the devices are removed only if they aren't part of a mounte
filesystem.
This new ioctl provides:
- release of unwanted btrfs_fs_devices and btrfs_devices structures
from memory if the device is not going to be mounted
- ability to mount filesystem in degraded mode, when one devices is
corrupted like in split brain raid1
- running test cases which would require reloading the kernel module
but this is not possible eg. due to mounted filesystem or built-in
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Both btrfs_find_device() and find_device() does the same thing except
that the latter does not take the seed device onto account in the device
scanning context. We can merge them.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Preparatory patch to add ioctl that allows to forget a device (ie.
reverse of scan).
Refactors btrfs_free_stale_devices() to obtain return status. As this
function can fail if it can't find the given path (returns -ENOENT) or
trying to delete a mounted device (returns -EBUSY).
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_find_device() accepts fs_info as an argument and retrieves
fs_devices from fs_info.
Instead use fs_devices, so that this function can be used in non-mount
(during device scanning) context as well.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_find_device_by_devspec() finds the device by @devid or by
@device_path. This patch makes code flow easy to read by open coding the
else part and renames devpath to device_path.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_find_device_missing_or_by_path() is relatively small function, and
its only parent btrfs_find_device_by_devspec() is small as well. Besides
there are a number of find_device functions. Merge
btrfs_find_device_missing_or_by_path() into its parent.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
alloc_fs_devices() can return ERR_PTR(-ENOMEM), so dereferencing its
result before the check for IS_ERR() is a bad idea.
Fixes: d1a6300282 ("btrfs: add members to fs_devices to track fsid changes")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Linux v5.0-rc1 will fail fstests/btrfs/163 with the following kernel
message:
BTRFS error (device dm-6): dev extent devid 1 physical offset 13631488 len 8388608 is beyond device boundary 0
BTRFS error (device dm-6): failed to verify dev extents against chunks: -117
BTRFS error (device dm-6): open_ctree failed
[CAUSE]
Commit cf90d884b3 ("btrfs: Introduce mount time chunk <-> dev extent
mapping check") introduced strict check on dev extents.
We use btrfs_find_device() with dev uuid and fs uuid set to NULL, and
only dependent on @devid to find the real device.
For seed devices, we call clone_fs_devices() in open_seed_devices() to
allow us search seed devices directly.
However clone_fs_devices() just populates devices with devid and dev
uuid, without populating other essential members, like disk_total_bytes.
This makes any device returned by btrfs_find_device(fs_info, devid,
NULL, NULL) is just a dummy, with 0 disk_total_bytes, and any dev
extents on the seed device will not pass the device boundary check.
[FIX]
This patch will try to verify the device returned by btrfs_find_device()
and if it's a dummy then re-search in seed devices.
Fixes: cf90d884b3 ("btrfs: Introduce mount time chunk <-> dev extent mapping check")
CC: stable@vger.kernel.org # 4.19+
Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The typos accumulate over time so once in a while time they get fixed in
a large patch.
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The first step of the rebalance process ensures there is 1MiB free on
each device. This number seems rather small. And in fact when talking to
the original authors their opinions were:
"man that's a little bonkers"
"i don't think we even need that code anymore"
"I think it was there to make sure we had room for the blank 1M at the
beginning. I bet it goes all the way back to v0"
"we just don't need any of that tho, i say we just delete it"
Clearly, this piece of code has lost its original intent throughout the
years. It doesn't really bring any real practical benefits to the
relocation process.
Additionally, this patch makes the balance process more lightweight by
removing a pair of shrink/grow operations which are rather expensive for
heavily populated filesystems. This is mainly due to shrink requiring
relocating block groups, involving heavy use of the btree.
The intermediate shrink/grow can fail and leave the filesystem in a
middle state that would need to be changed back by the user.
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Constructs like 'var & (PAGE_SIZE - 1)' or 'var & ~PAGE_MASK' can denote an
offset into a page.
So replace them by the offset_in_page() macro instead of open-coding it if
they're not used as an alignment check.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The dev-replace locking functions are now trivial wrappers around rw
semaphore that can be used directly everywhere. No functional change.
Signed-off-by: David Sterba <dsterba@suse.com>
After the rw semaphore has been added, the custom blocking using
::blocking_readers and ::read_lock_wq is redundant.
The blocking logic in __btrfs_map_block is replaced by extending the
time the semaphore is held, that has the same blocking effect on writes
as the previous custom scheme that waited until ::blocking_readers was
zero.
Signed-off-by: David Sterba <dsterba@suse.com>
This function really checks whether adding more data to the bio will
straddle a stripe/chunk. So first let's give it a more appropraite name
- btrfs_bio_fits_in_stripe. Secondly, the offset parameter was never
used to just remove it. Thirdly, pages are submitted to either btree or
data inodes so it's guaranteed that tree->ops is set so replace the
check with an ASSERT. Finally, document the parameters of the function.
No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Print a kernel log message when the balance ends, either for cancel or
completed or if it is paused.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The information about balance arguments is important for system audit,
this patch prints the textual representation when balance starts or is
resumed.
Example command:
$ btrfs balance start -f -mprofiles=raid1,convert=single,soft -dlimit=10..20,usage=50 /btrfs
Example kernel log output:
BTRFS info (device sdb): balance: start -f -dusage=50,limit=10..20 -mconvert=single,soft,profiles=raid1 -sconvert=single,soft,profiles=raid1
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog, simplify code ]
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out helper that describes block group flags from
describe_relocation. The result will not be longer than the given size.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
The available allocation bits members from struct btrfs_fs_info are
protected by a sequence lock, and when starting balance we access them
incorrectly in two different ways:
1) In the read sequence lock loop at btrfs_balance() we use the values we
read from fs_info->avail_*_alloc_bits and we can immediately do actions
that have side effects and can not be undone (printing a message and
jumping to a label). This is wrong because a retry might be needed, so
our actions must not have side effects and must be repeatable as long
as read_seqretry() returns a non-zero value. In other words, we were
essentially ignoring the sequence lock;
2) Right below the read sequence lock loop, we were reading the values
from avail_metadata_alloc_bits and avail_data_alloc_bits without any
protection from concurrent writers, that is, reading them outside of
the read sequence lock critical section.
So fix this by making sure we only read the available allocation bits
while in a read sequence lock critical section and that what we do in the
critical section is repeatable (has nothing that can not be undone) so
that any eventual retry that is needed is handled properly.
Fixes: de98ced9e7 ("Btrfs: use seqlock to protect fs_info->avail_{data, metadata, system}_alloc_bits")
Fixes: 1450612797 ("btrfs: fix a bogus warning when converting only data or metadata")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch lands the last case which needs to be handled by the fsid
change code. Namely, this is the case where a multidisk filesystem has
already undergone at least one successful fsid change i.e all disks
have the METADATA_UUID incompat bit and power failure occurs as another
fsid change is in progress. When such an event occurs, disks could be
split in 2 groups. One of the groups will have both METADATA_UUID and
CHANGING_FSID_V2 flags set coupled with old fsid/metadata_uuid pairs.
The other group of disks will have only METADATA_UUID bit set and their
fsid will be different than the one in disks in the first group. Here
we look at the following cases:
a) A disk from the first group is scanned first, so fs_devices is
created with stale fsid/metdata_uuid. Then when a disk from the
second group is scanned it needs to first check whether there exists
such an fs_devices that has fsid_change set to true (because it was
created with a disk having the CHANGING_FSID_V2 flag), the
metadata_uuid and fsid of the fs_devices will be different (since it was
created by a disk which already has had at least 1 successful fsid change)
and finally the metadata_uuid of the fs_devices will equal that of the
currently scanned disk (because metadata_uuid never really changes).
When the correct fs_devices is found the information from the scanned
disk will replace the current one in fs_devices since the scanned disk
will have higher generation number.
b) A disk from the second group is scanned so fs_devices is created
as usual with differing fsid/metdata_uid. Then when a disk from the
first group is scanned the code detects that it has both
CHANGING_FSID_V2 and METADATA_UUID flags set and will search for
fs_devices that has differing metadata_uuid/fsid and whose
metadata_uuid is the same as that of the scanned device.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit continues hardening the scanning code to handle cases where
power loss could have caused disks in a multi-disk filesystem to be
in inconsistent state. Namely handle the situation that can occur when
some of the disks in multi-disk fs have completed their fsid change i.e
they have METADATA_UUID incompat flag set, have cleared the
CHANGING_FSID_V2 flag and their fsid/metadata_uuid are different. At
the same time the other half of the disks will have their
fsid/metadata_uuid unchanged and will only have CHANGING_FSID_V2 flag.
This is handled by introducing code in the scan path which:
a) Handles the case when a device with CHANGING_FSID_V2 flag is
scanned and as a result btrfs_fs_devices is created with matching
fsid/metdata_uuid. Subsequently, when a device with completed fsid
change is scanned it will detect this via the new code in find_fsid
i.e that such an fs_devices exist that fsid_change flag is set to true,
it's metadata_uuid/fsid match and the metadata_uuid of the scanned
device matches that of the fs_devices. In this case, it's important to
note that the devices which has its fsid change completed will have a
higher generation number than the device with FSID_CHANGING_V2 flag
set, so its superblock block will be used during mount. To prevent an
assertion triggering because the sb used for mounting will have
differing fsid/metadata_uuid than the ones in the fs_devices struct
also add code in device_list_add which overwrites the values in
fs_devices.
b) Alternatively we can end up with a device that completed its
fsid change be scanned first which will create the respective
btrfs_fs_devices struct with differing fsid/metadata_uuid. In this
case when a device with FSID_CHANGING_V2 flag set is scanned it will
call the newly added find_fsid_inprogress function which will return
the correct fs_devices.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In order to gracefully handle split-brain scenario during fsid change
(which are very unlikely, yet possible), two more pieces of information
will be necessary:
1. The highest generation number among all devices registered to a
particular btrfs_fs_devices
2. A boolean flag whether a given btrfs_fs_devices was created by a
device which had the FSID_CHANGING_V2 flag set.
This is a preparatory patch and just introduces the variables as well
as code which sets them, their actual use is going to happen in a later
patch.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_fs_info structure contains a copy of the
fsid/metadata_uuid fields. Same values are also contained in the
btrfs_fs_devices structure which fs_info has a reference to. Let's
reduce duplication by removing the fields from fs_info and always refer
to the ones in fs_devices. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This field is going to be used when the user wants to change the UUID
of the filesystem without having to rewrite all metadata blocks. This
field adds another level of indirection such that when the FSID is
changed what really happens is the current UUID (the one with which the
fs was created) is copied to the 'metadata_uuid' field in the superblock
as well as a new incompat flag is set METADATA_UUID. When the kernel
detects this flag is set it knows that the superblock in fact has 2
UUIDs:
1. Is the UUID which is user-visible, currently known as FSID.
2. Metadata UUID - this is the UUID which is stamped into all on-disk
datastructures belonging to this file system.
When the new incompat flag is present device scanning checks whether
both fsid/metadata_uuid of the scanned device match any of the
registered filesystems. When the flag is not set then both UUIDs are
equal and only the FSID is retained on disk, metadata_uuid is set only
in-memory during mount.
Additionally a new metadata_uuid field is also added to the fs_info
struct. It's initialised either with the FSID in case METADATA_UUID
incompat flag is not set or with the metdata_uuid of the superblock
otherwise.
This commit introduces the new fields as well as the new incompat flag
and switches all users of the fsid to the new logic.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor updates in comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
It's unnecessary to check map->stripes[i].dev for NULL given its value
is already set and dereferenced above the the check. No functional
changes.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's not that impossible to imagine that a device OR a btrfs image is
copied just by using the dd or the cp command. Which in case both the
copies of the btrfs will have the same fsid. If on the system with
automount enabled, the copied FS gets scanned.
We have a known bug in btrfs, that we let the device path be changed
after the device has been mounted. So using this loop hole the new
copied device would appears as if its mounted immediately after it's
been copied.
For example:
Initially.. /dev/mmcblk0p4 is mounted as /
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
mmcblk0 179:0 0 29.2G 0 disk
|-mmcblk0p4 179:4 0 4G 0 part /
|-mmcblk0p2 179:2 0 500M 0 part /boot
|-mmcblk0p3 179:3 0 256M 0 part [SWAP]
`-mmcblk0p1 179:1 0 256M 0 part /boot/efi
$ btrfs fi show
Label: none uuid: 07892354-ddaa-4443-90ea-f76a06accaba
Total devices 1 FS bytes used 1.40GiB
devid 1 size 4.00GiB used 3.00GiB path /dev/mmcblk0p4
Copy mmcblk0 to sda
$ dd if=/dev/mmcblk0 of=/dev/sda
And immediately after the copy completes the change in the device
superblock is notified which the automount scans using btrfs device scan
and the new device sda becomes the mounted root device.
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 1 14.9G 0 disk
|-sda4 8:4 1 4G 0 part /
|-sda2 8:2 1 500M 0 part
|-sda3 8:3 1 256M 0 part
`-sda1 8:1 1 256M 0 part
mmcblk0 179:0 0 29.2G 0 disk
|-mmcblk0p4 179:4 0 4G 0 part
|-mmcblk0p2 179:2 0 500M 0 part /boot
|-mmcblk0p3 179:3 0 256M 0 part [SWAP]
`-mmcblk0p1 179:1 0 256M 0 part /boot/efi
$ btrfs fi show /
Label: none uuid: 07892354-ddaa-4443-90ea-f76a06accaba
Total devices 1 FS bytes used 1.40GiB
devid 1 size 4.00GiB used 3.00GiB path /dev/sda4
The bug is quite nasty that you can't either unmount /dev/sda4 or
/dev/mmcblk0p4. And the problem does not get solved until you take sda
out of the system on to another system to change its fsid using the
'btrfstune -u' command.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of hardcoding exceptions for RAID5 and RAID6 in the code, use an
nparity field in raid_attr.
Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>
RAID5 and RAID6 profile store one copy of the data, not 2 or 3. These
values are not yet used anywhere so there's no change.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 92e222df7b "btrfs: alloc_chunk: fix DUP stripe size handling"
fixed calculating the stripe_size for a new DUP chunk.
However, the same calculation reappears a bit later, and that one was
not changed yet. The resulting bug that is exposed is that the newly
allocated device extents ('stripes') can have a few MiB overlap with the
next thing stored after them, which is another device extent or the end
of the disk.
The scenario in which this can happen is:
* The block device for the filesystem is less than 10GiB in size.
* The amount of contiguous free unallocated disk space chosen to use for
chunk allocation is 20% of the total device size, or a few MiB more or
less.
An example:
- The filesystem device is 7880MiB (max_chunk_size gets set to 788MiB)
- There's 1578MiB unallocated raw disk space left in one contiguous
piece.
In this case stripe_size is first calculated as 789MiB, (half of
1578MiB).
Since 789MiB (stripe_size * data_stripes) > 788MiB (max_chunk_size), we
enter the if block. Now stripe_size value is immediately overwritten
while calculating an adjusted value based on max_chunk_size, which ends
up as 788MiB.
Next, the value is rounded up to a 16MiB boundary, 800MiB, which is
actually more than the value we had before. However, the last comparison
fails to detect this, because it's comparing the value with the total
amount of free space, which is about twice the size of stripe_size.
In the example above, this means that the resulting raw disk space being
allocated is 1600MiB, while only a gap of 1578MiB has been found. The
second device extent object for this DUP chunk will overlap for 22MiB
with whatever comes next.
The underlying problem here is that the stripe_size is reused all the
time for different things. So, when entering the code in the if block,
stripe_size is immediately overwritten with something else. If later we
decide we want to have the previous value back, then the logic to
compute it was copy pasted in again.
With this change, the value in stripe_size is not unnecessarily
destroyed, so the duplicated calculation is not needed any more.
Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The variable num_bytes is really a way too generic name for a variable
in this function. There are a dozen other variables that hold a number
of bytes as value.
Give it a name that actually describes what it does, which is holding
the size of the chunk that we're allocating.
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The variable num_bytes is used to store the chunk length of the chunk
that we're allocating. Do not reuse it for something really different in
the same function.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before btrfs_map_bio submits all stripe bios it does a number of checks
to ensure the device for every stripe is present. However, it doesn't do
a DEV_STATE_MISSING check, instead this is relegated to the lower level
btrfs_schedule_bio (in the async submission case, sync submission
doesn't check DEV_STATE_MISSING at all). Additionally
btrfs_schedule_bios does the duplicate device->bdev check which has
already been performed in btrfs_map_bio.
This patch moves the DEV_STATE_MISSING check in btrfs_map_bio and
removes the duplicate device->bdev check. Doing so ensures that no bio
cloning/submission happens for both async/sync requests in the face of
missing device. This makes the async io submission path slightly shorter
in terms of instruction count. No functional changes.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The Btrfs swap code is going to need it, so give it a btrfs_ prefix and
make it non-static.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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>
Add extra dev extent end check against device boundary.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enhance btrfs_verify_dev_extents() to remember previous checked dev
extents, so it can verify no dev extents can overlap.
Analysis from Hans:
"Imagine allocating a DATA|DUP chunk.
In the chunk allocator, we first set...
max_stripe_size = SZ_1G;
max_chunk_size = BTRFS_MAX_DATA_CHUNK_SIZE
... which is 10GiB.
Then...
/* we don't want a chunk larger than 10% of writeable space */
max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
max_chunk_size);
Imagine we only have one 7880MiB block device in this filesystem. Now
max_chunk_size is down to 788MiB.
The next step in the code is to search for max_stripe_size * dev_stripes
amount of free space on the device, which is in our example 1GiB * 2 =
2GiB. Imagine the device has exactly 1578MiB free in one contiguous
piece. This amount of bytes will be put in devices_info[ndevs - 1].max_avail
Next we recalculate the stripe_size (which is actually the device extent
length), based on the actual maximum amount of available raw disk space:
stripe_size = div_u64(devices_info[ndevs - 1].max_avail, dev_stripes);
stripe_size is now 789MiB
Next we do...
data_stripes = num_stripes / ncopies
...where data_stripes ends up as 1, because num_stripes is 2 (the amount
of device extents we're going to have), and DUP has ncopies 2.
Next there's a check...
if (stripe_size * data_stripes > max_chunk_size)
...which matches because 789MiB * 1 > 788MiB.
We go into the if code, and next is...
stripe_size = div_u64(max_chunk_size, data_stripes);
...which resets stripe_size to max_chunk_size: 788MiB
Next is a fun one...
/* bump the answer up to a 16MB boundary */
stripe_size = round_up(stripe_size, SZ_16M);
...which changes stripe_size from 788MiB to 800MiB.
We're not done changing stripe_size yet...
/* But don't go higher than the limits we found while searching
* for free extents
*/
stripe_size = min(devices_info[ndevs - 1].max_avail,
stripe_size);
This is bad. max_avail is twice the stripe_size (we need to fit 2 device
extents on the same device for DUP).
The result here is that 800MiB < 1578MiB, so it's unchanged. However,
the resulting DUP chunk will need 1600MiB disk space, which isn't there,
and the second dev_extent might extend into the next thing (next
dev_extent? end of device?) for 22MiB.
The last shown line of code relies on a situation where there's twice
the value of stripe_size present as value for the variable stripe_size
when it's DUP. This was actually the case before commit 92e222df7b
"btrfs: alloc_chunk: fix DUP stripe size handling", from which I quote:
"[...] in the meantime there's a check to see if the stripe_size does
not exceed max_chunk_size. Since during this check stripe_size is twice
the amount as intended, the check will reduce the stripe_size to
max_chunk_size if the actual correct to be used stripe_size is more than
half the amount of max_chunk_size."
In the previous version of the code, the 16MiB alignment (why is this
done, by the way?) would result in a 50% chance that it would actually
do an 8MiB alignment for the individual dev_extents, since it was
operating on double the size. Does this matter?
Does it matter that stripe_size can be set to anything which is not
16MiB aligned because of the amount of remaining available disk space
which is just taken?
What is the main purpose of this round_up?
The most straightforward thing to do seems something like...
stripe_size = min(
div_u64(devices_info[ndevs - 1].max_avail, dev_stripes),
stripe_size
)
..just putting half of the max_avail into stripe_size."
Link: https://lore.kernel.org/linux-btrfs/b3461a38-e5f8-f41d-c67c-2efac8129054@mendix.com/
Reported-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
[ add analysis from report ]
Signed-off-by: David Sterba <dsterba@suse.com>
There's a single caller and the function name does not say it's actually
taking the lock, so open coding makes it more explicit.
For now, btrfs_dev_replace_read_lock is used instead of read_lock so
it's paired with the unlocking wrapper in the same block.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helper does the same math and we take care about the special case
when flags is 0 too.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
rb_first_cached() trades an extra pointer "leftmost" for doing the
same job as rb_first() but in O(1).
As evict_inode_truncate_pages() removes all extent mapping by always
looking for the first rb entry, it's helpful to use rb_first_cached
instead.
For more details about the optimization see patch "Btrfs: delayed-refs:
use rb_first_cached for href_root".
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
