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2 months agobtrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()
robbieko [Wed, 25 Mar 2026 10:18:15 +0000 (18:18 +0800)] 
btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()

After commit 1618aa3c2e01 ("btrfs: simplify return variables in
lookup_extent_data_ref()"), the err and ret variables were merged into
a single ret variable. However, when btrfs_next_leaf() returns 0
(success), ret is overwritten from -ENOENT to 0. If the first key in
the next leaf does not match (different objectid or type), the function
returns 0 instead of -ENOENT, making the caller believe the lookup
succeeded when it did not. This can lead to operations on the wrong
extent tree item, potentially causing extent tree corruption.

Fix this by returning -ENOENT directly when the key does not match,
instead of relying on the ret variable.

Fixes: 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: robbieko <robbieko@synology.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix lost error when running device stats on multiple devices fs
Filipe Manana [Wed, 18 Mar 2026 16:17:59 +0000 (16:17 +0000)] 
btrfs: fix lost error when running device stats on multiple devices fs

Whenever we get an error updating the device stats item for a device in
btrfs_run_dev_stats() we allow the loop to go to the next device, and if
updating the stats item for the next device succeeds, we end up losing
the error we had from the previous device.

Fix this by breaking out of the loop once we get an error and make sure
it's returned to the caller. Since we are in the transaction commit path
(and in the critical section actually), returning the error will result
in a transaction abort.

Fixes: 733f4fbbc108 ("Btrfs: read device stats on mount, write modified ones during commit")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()
Goldwyn Rodrigues [Fri, 13 Mar 2026 18:11:39 +0000 (14:11 -0400)] 
btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()

If overlay is used on top of btrfs, dentry->d_sb translates to overlay's
super block and fsid assignment will lead to a crash.

Use file_inode(file)->i_sb to always get btrfs_sb.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: zlib: handle page aligned compressed size correctly
Qu Wenruo [Fri, 13 Mar 2026 08:05:26 +0000 (18:35 +1030)] 
btrfs: zlib: handle page aligned compressed size correctly

[BUG]
Since commit 3d74a7556fba ("btrfs: zlib: introduce zlib_compress_bio()
helper"), there are some reports about different crashes in zlib
compression path. One of the symptoms is list corruption like the
following:

  list_del corruption. next->prev should be fffffbb340204a08, but was ffff8d6517cb7de0. (next=fffffbb3402d62c8)
  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:65!
  Oops: invalid opcode: 0000 [#1] SMP NOPTI
  CPU: 1 UID: 0 PID: 21436 Comm: kworker/u16:7 Not tainted 7.0.0-rc2-jcg+ #1 PREEMPT
  Hardware name: LENOVO 10VGS02P00/3130, BIOS M1XKT57A 02/10/2022
  Workqueue: btrfs-delalloc btrfs_work_helper [btrfs]
  RIP: 0010:__list_del_entry_valid_or_report+0xec/0xf0
  Call Trace:
   <TASK>
   btrfs_alloc_compr_folio+0xae/0xc0 [btrfs]
   zlib_compress_bio+0x39d/0x6a0 [btrfs]
   btrfs_compress_bio+0x2e3/0x3d0 [btrfs]
   compress_file_range+0x2b0/0x660 [btrfs]
   btrfs_work_helper+0xdb/0x3e0 [btrfs]
   process_one_work+0x192/0x3d0
   worker_thread+0x19a/0x310
   kthread+0xdf/0x120
   ret_from_fork+0x22e/0x310
   ret_from_fork_asm+0x1a/0x30
   </TASK>
  ---[ end trace 0000000000000000 ]---

Other symptoms include VM_BUG_ON() during folio_put() but it's rarer.

David Sterba firstly reported this during his CI runs but unfortunately
I'm unable to hit it.

Meanwhile zstd/lzo doesn't seem to have the same problem.

[CAUSE]
During zlib_compress_bio() every time the output buffer is full, we
queue the full folio into the compressed bio, and allocate a new folio
as the output folio.

After the input has finished, we loop through zlib_deflate() with
Z_FINISH to flush all output.

And when that is done, we still need to check if the last folio has any
content, and if so we still need to queue that part into the compressed
bio.

The problem is in the final folio handling, if the final folio is full
(for x86_64 the folio size is 4K), the length to queue is calculated by

  u32 cur_len = offset_in_folio(out_folio, workspace->strm.total_out);

But since total_out is 4K aligned, the resulted @cur_len will be 0, then
we hit the bio_add_folio(), which has a quirk that if bio_add_folio()
got an length 0, it will still queue the folio into the bio, but return
false.

In that case we go to out: tag, which calls btrfs_free_compr_folio() to
release @out_folio, which may put the out folio into the btrfs global
pool list.

On the other hand, that @out_folio is already added to the
compressed bio, and will later be released again by
cleanup_compressed_bio(), which results double release.

And if this time we still need to put the folio into the btrfs global
pool list, it will result a list corruption because it's already in the
list.

[FIX]
Instead of offset_inside_folio(), directly use the difference between
strm.total_out and bi_size.
So that if the last folio is completely full, we can still properly
queue the full folio other than queueing zero byte.

Fixes: 3d74a7556fba ("btrfs: zlib: introduce zlib_compress_bio() helper")
Reported-by: David Sterba <dsterba@suse.com>
Reported-by: Jean-Christophe Guillain <jean-christophe@guillain.net>
Reported-by: syzbot+3c4d8371d65230f852a2@syzkaller.appspotmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221176
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix leak of kobject name for sub-group space_info
Shin'ichiro Kawasaki [Sun, 1 Mar 2026 12:17:04 +0000 (21:17 +0900)] 
btrfs: fix leak of kobject name for sub-group space_info

When create_space_info_sub_group() allocates elements of
space_info->sub_group[], kobject_init_and_add() is called for each
element via btrfs_sysfs_add_space_info_type(). However, when
check_removing_space_info() frees these elements, it does not call
btrfs_sysfs_remove_space_info() on them. As a result, kobject_put() is
not called and the associated kobj->name objects are leaked.

This memory leak is reproduced by running the blktests test case
zbd/009 on kernels built with CONFIG_DEBUG_KMEMLEAK. The kmemleak
feature reports the following error:

unreferenced object 0xffff888112877d40 (size 16):
  comm "mount", pid 1244, jiffies 4294996972
  hex dump (first 16 bytes):
    64 61 74 61 2d 72 65 6c 6f 63 00 c4 c6 a7 cb 7f  data-reloc......
  backtrace (crc 53ffde4d):
    __kmalloc_node_track_caller_noprof+0x619/0x870
    kstrdup+0x42/0xc0
    kobject_set_name_vargs+0x44/0x110
    kobject_init_and_add+0xcf/0x150
    btrfs_sysfs_add_space_info_type+0xfc/0x210 [btrfs]
    create_space_info_sub_group.constprop.0+0xfb/0x1b0 [btrfs]
    create_space_info+0x211/0x320 [btrfs]
    btrfs_init_space_info+0x15a/0x1b0 [btrfs]
    open_ctree+0x33c7/0x4a50 [btrfs]
    btrfs_get_tree.cold+0x9f/0x1ee [btrfs]
    vfs_get_tree+0x87/0x2f0
    vfs_cmd_create+0xbd/0x280
    __do_sys_fsconfig+0x3df/0x990
    do_syscall_64+0x136/0x1540
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

To avoid the leak, call btrfs_sysfs_remove_space_info() instead of
kfree() for the elements.

Fixes: f92ee31e031c ("btrfs: introduce btrfs_space_info sub-group")
Link: https://lore.kernel.org/linux-block/b9488881-f18d-4f47-91a5-3c9bf63955a5@wdc.com/
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix zero size inode with non-zero size after log replay
Filipe Manana [Tue, 17 Feb 2026 14:46:50 +0000 (14:46 +0000)] 
btrfs: fix zero size inode with non-zero size after log replay

When logging that an inode exists, as part of logging a new name or
logging new dir entries for a directory, we always set the generation of
the logged inode item to 0. This is to signal during log replay (in
overwrite_item()), that we should not set the i_size since we only logged
that an inode exists, so the i_size of the inode in the subvolume tree
must be preserved (as when we log new names or that an inode exists, we
don't log extents).

This works fine except when we have already logged an inode in full mode
or it's the first time we are logging an inode created in a past
transaction, that inode has a new i_size of 0 and then we log a new name
for the inode (due to a new hardlink or a rename), in which case we log
an i_size of 0 for the inode and a generation of 0, which causes the log
replay code to not update the inode's i_size to 0 (in overwrite_item()).

An example scenario:

  mkdir /mnt/dir
  xfs_io -f -c "pwrite 0 64K" /mnt/dir/foo

  sync

  xfs_io -c "truncate 0" -c "fsync" /mnt/dir/foo

  ln /mnt/dir/foo /mnt/dir/bar

  xfs_io -c "fsync" /mnt/dir

  <power fail>

After log replay the file remains with a size of 64K. This is because when
we first log the inode, when we fsync file foo, we log its current i_size
of 0, and then when we create a hard link we log again the inode in exists
mode (LOG_INODE_EXISTS) but we set a generation of 0 for the inode item we
add to the log tree, so during log replay overwrite_item() sees that the
generation is 0 and i_size is 0 so we skip updating the inode's i_size
from 64K to 0.

Fix this by making sure at fill_inode_item() we always log the real
generation of the inode if it was logged in the current transaction with
the i_size we logged before. Also if an inode created in a previous
transaction is logged in exists mode only, make sure we log the i_size
stored in the inode item located from the commit root, so that if we log
multiple times that the inode exists we get the correct i_size.

A test case for fstests will follow soon.

Reported-by: Vyacheslav Kovalevsky <slava.kovalevskiy.2014@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/af8c15fa-4e41-4bb2-885c-0bc4e97532a6@gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix super block offset in error message in btrfs_validate_super()
Mark Harmstone [Tue, 17 Feb 2026 17:35:42 +0000 (17:35 +0000)] 
btrfs: fix super block offset in error message in btrfs_validate_super()

Fix the superblock offset mismatch error message in
btrfs_validate_super(): we changed it so that it considers all the
superblocks, but the message still assumes we're only looking at the
first one.

The change from %u to %llu is because we're changing from a constant to
a u64.

Fixes: 069ec957c35e ("btrfs: Refactor btrfs_check_super_valid")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: reject root items with drop_progress and zero drop_level
ZhengYuan Huang [Thu, 12 Mar 2026 00:14:43 +0000 (08:14 +0800)] 
btrfs: reject root items with drop_progress and zero drop_level

[BUG]
When recovering relocation at mount time, merge_reloc_root() and
btrfs_drop_snapshot() both use BUG_ON(level == 0) to guard against
an impossible state: a non-zero drop_progress combined with a zero
drop_level in a root_item, which can be triggered:

------------[ cut here ]------------
kernel BUG at fs/btrfs/relocation.c:1545!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 283 ... Tainted: 6.18.0+ #16 PREEMPT(voluntary)
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Ubuntu 24.04 PC v2, BIOS 1.16.3-debian-1.16.3-2
RIP: 0010:merge_reloc_root+0x1266/0x1650 fs/btrfs/relocation.c:1545
Code: ffff0000 00004589 d7e9acfa ffffe8a1 79bafebe 02000000
Call Trace:
 merge_reloc_roots+0x295/0x890 fs/btrfs/relocation.c:1861
 btrfs_recover_relocation+0xd6e/0x11d0 fs/btrfs/relocation.c:4195
 btrfs_start_pre_rw_mount+0xa4d/0x1810 fs/btrfs/disk-io.c:3130
 open_ctree+0x5824/0x5fe0 fs/btrfs/disk-io.c:3640
 btrfs_fill_super fs/btrfs/super.c:987 [inline]
 btrfs_get_tree_super fs/btrfs/super.c:1951 [inline]
 btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline]
 btrfs_get_tree+0x111c/0x2190 fs/btrfs/super.c:2128
 vfs_get_tree+0x9a/0x370 fs/super.c:1758
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3642 [inline]
 do_new_mount fs/namespace.c:3718 [inline]
 path_mount+0x5b8/0x1ea0 fs/namespace.c:4028
 do_mount fs/namespace.c:4041 [inline]
 __do_sys_mount fs/namespace.c:4229 [inline]
 __se_sys_mount fs/namespace.c:4206 [inline]
 __x64_sys_mount+0x282/0x320 fs/namespace.c:4206
 ...
RIP: 0033:0x7f969c9a8fde
Code: 0f1f4000 48c7c2b0 fffffff7 d8648902 b8ffffff ffc3660f
---[ end trace 0000000000000000 ]---

The bug is reproducible on 7.0.0-rc2-next-20260310 with our dynamic
metadata fuzzing tool that corrupts btrfs metadata at runtime.

[CAUSE]
A non-zero drop_progress.objectid means an interrupted
btrfs_drop_snapshot() left a resume point on disk, and in that case
drop_level must be greater than 0 because the checkpoint is only
saved at internal node levels.

Although this invariant is enforced when the kernel writes the root
item, it is not validated when the root item is read back from disk.
That allows on-disk corruption to provide an invalid state with
drop_progress.objectid != 0 and drop_level == 0.

When relocation recovery later processes such a root item,
merge_reloc_root() reads drop_level and hits BUG_ON(level == 0). The
same invalid metadata can also trigger the corresponding BUG_ON() in
btrfs_drop_snapshot().

[FIX]
Fix this by validating the root_item invariant in tree-checker when
reading root items from disk: if drop_progress.objectid is non-zero,
drop_level must also be non-zero. Reject such malformed metadata with
-EUCLEAN before it reaches merge_reloc_root() or btrfs_drop_snapshot()
and triggers the BUG_ON.

After the fix, the same corruption is correctly rejected by tree-checker
and the BUG_ON is no longer triggered.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: ZhengYuan Huang <gality369@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: check block group before marking it unused in balance_remap_chunks()
Mark Harmstone [Thu, 19 Feb 2026 19:19:00 +0000 (19:19 +0000)] 
btrfs: check block group before marking it unused in balance_remap_chunks()

Fix a potential segfault in balance_remap_chunks(): if we quit early
because btrfs_inc_block_group_ro() fails, all the remaining items in the
chunks list will still have their bg value set to NULL. It's thus not
safe to dereference this pointer without checking first.

Reported-by: Chris Mason <clm@fb.com>
Link: https://lore.kernel.org/linux-btrfs/20260125120717.1578828-1-clm@meta.com/
Fixes: 81e5a4551c32 ("btrfs: allow balancing remap tree")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: hold block group reference during entire move_existing_remap()
Mark Harmstone [Thu, 19 Feb 2026 17:03:53 +0000 (17:03 +0000)] 
btrfs: hold block group reference during entire move_existing_remap()

There is a potential use-after-free in move_existing_remap(): we're calling
btrfs_put_block_group() on dest_bg, then passing it to
btrfs_add_block_group_free_space() a few lines later.

Fix this by getting the BG at the start of the function and putting it
near the end. This also means we're not doing a lookup twice for the
same thing.

Reported-by: Chris Mason <clm@fb.com>
Link: https://lore.kernel.org/linux-btrfs/20260125123908.2096548-1-clm@meta.com/
Fixes: bbea42dfb91f ("btrfs: move existing remaps before relocating block group")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix an incorrect ASSERT() condition inside lzo_decompress_bio()
Qu Wenruo [Thu, 19 Feb 2026 08:21:14 +0000 (18:51 +1030)] 
btrfs: fix an incorrect ASSERT() condition inside lzo_decompress_bio()

[BUG]
When running btrfs/284 with 64K page size and 4K fs block size, it
crashes with the following ASSERT() triggered:

  BTRFS info (device dm-3): use lzo compression, level 1
  assertion failed: folio_size(fi.folio) == sectorsize :: 0, in lzo.c:450
  ------------[ cut here ]------------
  kernel BUG at lzo.c:450!
  Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
  CPU: 4 UID: 0 PID: 329 Comm: kworker/u37:2 Tainted: G           OE       6.19.0-rc8-custom+ #185 PREEMPT(voluntary)
  Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
  Workqueue: btrfs-endio simple_end_io_work [btrfs]
  pc : lzo_decompress_bio+0x61c/0x630 [btrfs]
  lr : lzo_decompress_bio+0x61c/0x630 [btrfs]
  Call trace:
   lzo_decompress_bio+0x61c/0x630 [btrfs] (P)
   end_bbio_compressed_read+0x2a8/0x2c0 [btrfs]
   btrfs_bio_end_io+0xc4/0x258 [btrfs]
   btrfs_check_read_bio+0x424/0x7e0 [btrfs]
   simple_end_io_work+0x40/0xa8 [btrfs]
   process_one_work+0x168/0x3f0
   worker_thread+0x25c/0x398
   kthread+0x154/0x250
   ret_from_fork+0x10/0x20
  Code: 912a2021 b0000e00 91246000 940244e9 (d4210000)
  ---[ end trace 0000000000000000 ]---

[CAUSE]
Commit 37cc07cab7dc ("btrfs: lzo: use folio_iter to handle
lzo_decompress_bio()") added the ASSERT() to make sure the folio size
matches the fs block size.

But the check is completely wrong, the original intention is to make
sure for bs > ps cases, we always got a large folio that covers a full fs
block.

However for bs < ps cases, a folio can never be smaller than page size,
and the ASSERT() gets triggered immediately.

[FIX]
Check the folio size against @min_folio_size instead, which will never
be smaller than PAGE_SIZE, and still cover bs > ps cases.

Fixes: 37cc07cab7dc ("btrfs: lzo: use folio_iter to handle lzo_decompress_bio()")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix an incorrect ASSERT() condition inside zstd_decompress_bio()
Qu Wenruo [Thu, 19 Feb 2026 08:21:13 +0000 (18:51 +1030)] 
btrfs: fix an incorrect ASSERT() condition inside zstd_decompress_bio()

[BUG]
When running btrfs/284 with 64K page size and 4K fs block size, it
crashes with the following ASSERT() triggered:

  assertion failed: folio_size(fi.folio) == blocksize :: 0, in fs/btrfs/zstd.c:603
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/zstd.c:603!
  Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
  CPU: 2 UID: 0 PID: 1183 Comm: kworker/u35:4 Not tainted 6.19.0-rc8-custom+ #185 PREEMPT(voluntary)
  Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
  Workqueue: btrfs-endio simple_end_io_work [btrfs]
  pc : zstd_decompress_bio+0x4f0/0x508 [btrfs]
  lr : zstd_decompress_bio+0x4f0/0x508 [btrfs]
  Call trace:
   zstd_decompress_bio+0x4f0/0x508 [btrfs] (P)
   end_bbio_compressed_read+0x260/0x2c0 [btrfs]
   btrfs_bio_end_io+0xc4/0x258 [btrfs]
   btrfs_check_read_bio+0x424/0x7e0 [btrfs]
   simple_end_io_work+0x40/0xa8 [btrfs]
   process_one_work+0x168/0x3f0
   worker_thread+0x25c/0x398
   kthread+0x154/0x250
   ret_from_fork+0x10/0x20
  ---[ end trace 0000000000000000 ]---

[CAUSE]
Commit 1914b94231e9 ("btrfs: zstd: use folio_iter to handle
zstd_decompress_bio()") added the ASSERT() to make sure the folio size
matches the fs block size.

But the check is completely wrong, the original intention is to make
sure for bs > ps cases, we always got a large folio that covers a full fs
block.

However for bs < ps cases, a folio can never be smaller than page size,
and the ASSERT() gets triggered immediately.

[FIX]
Check the folio size against @min_folio_size instead, which will never
be smaller than PAGE_SIZE, and still cover bs > ps cases.

Fixes: 1914b94231e9 ("btrfs: zstd: use folio_iter to handle zstd_decompress_bio()")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: do not touch page cache for encoded writes
Qu Wenruo [Thu, 19 Feb 2026 08:21:12 +0000 (18:51 +1030)] 
btrfs: do not touch page cache for encoded writes

[BUG]
When running btrfs/284, the following ASSERT() will be triggered with
64K page size and 4K fs block size:

  assertion failed: folio_test_writeback(folio) :: 0, in subpage.c:476
  ------------[ cut here ]------------
  kernel BUG at subpage.c:476!
  Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
  CPU: 4 UID: 0 PID: 2313 Comm: kworker/u37:2 Tainted: G           OE       6.19.0-rc8-custom+ #185 PREEMPT(voluntary)
  Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
  Workqueue: btrfs-endio simple_end_io_work [btrfs]
  pc : btrfs_subpage_clear_writeback+0x148/0x160 [btrfs]
  lr : btrfs_subpage_clear_writeback+0x148/0x160 [btrfs]
  Call trace:
   btrfs_subpage_clear_writeback+0x148/0x160 [btrfs] (P)
   btrfs_folio_clamp_clear_writeback+0xb4/0xd0 [btrfs]
   end_compressed_writeback+0xe0/0x1e0 [btrfs]
   end_bbio_compressed_write+0x1e8/0x218 [btrfs]
   btrfs_bio_end_io+0x108/0x258 [btrfs]
   simple_end_io_work+0x68/0xa8 [btrfs]
   process_one_work+0x168/0x3f0
   worker_thread+0x25c/0x398
   kthread+0x154/0x250
   ret_from_fork+0x10/0x20
  ---[ end trace 0000000000000000 ]---

[CAUSE]
The offending bio is from an encoded write, where the compressed data is
directly written as a data extent, without touching the page cache.

However the encoded write still utilizes the regular buffered write path
for compressed data, by setting the compressed_bio::writeback flag.

When that flag is set, at end_bbio_compressed_write() btrfs will go
clearing the writeback flag of the folios in the page cache.

However for bs < ps cases, the subpage helper has one extra check to make
sure the folio has a writeback flag set in the first place.

But since it's an encoded write, we never go through page
cache, thus the folio has no writeback flag and triggers the ASSERT().

[FIX]
Do not set compressed_bio::writeback flag for encoded writes, and change
the ASSERT() in btrfs_submit_compressed_write() to make sure that flag
is not set.

Fixes: e1bc83f8b157 ("btrfs: get rid of compressed_folios[] usage for encoded writes")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: fix a bug that makes encoded write bio larger than expected
Qu Wenruo [Thu, 19 Feb 2026 08:21:11 +0000 (18:51 +1030)] 
btrfs: fix a bug that makes encoded write bio larger than expected

[BUG]
When running btrfs/284 with 64K page size and 4K fs block size, the
following ASSERT() can be triggered:

  assertion failed: cb->bbio.bio.bi_iter.bi_size == disk_num_bytes :: 0, in inode.c:9991
  ------------[ cut here ]------------
  kernel BUG at inode.c:9991!
  Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
  CPU: 5 UID: 0 PID: 6787 Comm: btrfs Tainted: G           OE       6.19.0-rc8-custom+ #1 PREEMPT(voluntary)
  Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
  pc : btrfs_do_encoded_write+0x9b0/0x9c0 [btrfs]
  lr : btrfs_do_encoded_write+0x9b0/0x9c0 [btrfs]
  Call trace:
   btrfs_do_encoded_write+0x9b0/0x9c0 [btrfs] (P)
   btrfs_do_write_iter+0x1d8/0x208 [btrfs]
   btrfs_ioctl_encoded_write+0x3c8/0x6d0 [btrfs]
   btrfs_ioctl+0xeb0/0x2b60 [btrfs]
   __arm64_sys_ioctl+0xac/0x110
   invoke_syscall.constprop.0+0x64/0xe8
   el0_svc_common.constprop.0+0x40/0xe8
   do_el0_svc+0x24/0x38
   el0_svc+0x3c/0x1b8
   el0t_64_sync_handler+0xa0/0xe8
   el0t_64_sync+0x1a4/0x1a8
  Code: 91180021 90001080 9111a000 94039d54 (d4210000)
  ---[ end trace 0000000000000000 ]---

[CAUSE]
After commit e1bc83f8b157 ("btrfs: get rid of compressed_folios[] usage
for encoded writes"), the encoded write is changed to copy the content
from the iov into a folio, and queue the folio into the compressed bio.

However we always queue the full folio into the compressed bio, which
can make the compressed bio larger than the on-disk extent, if the folio
size is larger than the fs block size.

Although we have an ASSERT() to catch such problem, for kernels without
CONFIG_BTRFS_ASSERT, such larger than expected bio will just be
submitted, possibly overwrite the next data extent, causing data
corruption.

[FIX]
Instead of blindly queuing the full folio into the compressed bio, only
queue the rounded up range, which is the old behavior before that
offending commit.
This also means we no longer need to zero the tailing range until the
folio end (but still to the block boundary), as such range will not be
submitted anyway.

And since we're here, add a final ASSERT() into
btrfs_submit_compressed_write() as the last safety net for kernels with
btrfs assertions enabled

Fixes: e1bc83f8b157 ("btrfs: get rid of compressed_folios[] usage for encoded writes")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: reserve enough transaction items for qgroup ioctls
Filipe Manana [Fri, 13 Feb 2026 16:08:53 +0000 (16:08 +0000)] 
btrfs: reserve enough transaction items for qgroup ioctls

Currently our qgroup ioctls don't reserve any space, they just do a
transaction join, which does not reserve any space, neither for the quota
tree updates nor for the delayed refs generated when updating the quota
tree. The quota root uses the global block reserve, which is fine most of
the time since we don't expect a lot of updates to the quota root, or to
be too close to -ENOSPC such that other critical metadata updates need to
resort to the global reserve.

However this is not optimal, as not reserving proper space may result in a
transaction abort due to not reserving space for delayed refs and then
abusing the use of the global block reserve.

For example, the following reproducer (which is unlikely to model any
real world use case, but just to illustrate the problem), triggers such a
transaction abort due to -ENOSPC when running delayed refs:

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/nullb0
  MNT=/mnt/nullb0

  umount $DEV &> /dev/null
  # Limit device to 1G so that it's much faster to reproduce the issue.
  mkfs.btrfs -f -b 1G $DEV
  mount -o commit=600 $DEV $MNT

  fallocate -l 800M $MNT/filler
  btrfs quota enable $MNT

  for ((i = 1; i <= 400000; i++)); do
      btrfs qgroup create 1/$i $MNT
  done

  umount $MNT

When running this, we can see in dmesg/syslog that a transaction abort
happened:

  [436.490] BTRFS error (device nullb0): failed to run delayed ref for logical 30408704 num_bytes 16384 type 176 action 1 ref_mod 1: -28
  [436.493] ------------[ cut here ]------------
  [436.494] BTRFS: Transaction aborted (error -28)
  [436.495] WARNING: fs/btrfs/extent-tree.c:2247 at btrfs_run_delayed_refs+0xd9/0x110 [btrfs], CPU#4: umount/2495372
  [436.497] Modules linked in: btrfs loop (...)
  [436.508] CPU: 4 UID: 0 PID: 2495372 Comm: umount Tainted: G        W           6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
  [436.510] Tainted: [W]=WARN
  [436.511] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [436.513] RIP: 0010:btrfs_run_delayed_refs+0xdf/0x110 [btrfs]
  [436.514] Code: 0f 82 ea (...)
  [436.518] RSP: 0018:ffffd511850b7d78 EFLAGS: 00010292
  [436.519] RAX: 00000000ffffffe4 RBX: ffff8f120dad37e0 RCX: 0000000002040001
  [436.520] RDX: 0000000000000002 RSI: 00000000ffffffe4 RDI: ffffffffc090fd80
  [436.522] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffffc04d1867
  [436.523] R10: ffff8f18dc1fffa8 R11: 0000000000000003 R12: ffff8f173aa89400
  [436.524] R13: 0000000000000000 R14: ffff8f173aa89400 R15: 0000000000000000
  [436.526] FS:  00007fe59045d840(0000) GS:ffff8f192e22e000(0000) knlGS:0000000000000000
  [436.527] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [436.528] CR2: 00007fe5905ff2b0 CR3: 000000060710a002 CR4: 0000000000370ef0
  [436.530] Call Trace:
  [436.530]  <TASK>
  [436.530]  btrfs_commit_transaction+0x73/0xc00 [btrfs]
  [436.531]  ? btrfs_attach_transaction_barrier+0x1e/0x70 [btrfs]
  [436.532]  sync_filesystem+0x7a/0x90
  [436.533]  generic_shutdown_super+0x28/0x180
  [436.533]  kill_anon_super+0x12/0x40
  [436.534]  btrfs_kill_super+0x12/0x20 [btrfs]
  [436.534]  deactivate_locked_super+0x2f/0xb0
  [436.534]  cleanup_mnt+0xea/0x180
  [436.535]  task_work_run+0x58/0xa0
  [436.535]  exit_to_user_mode_loop+0xed/0x480
  [436.536]  ? __x64_sys_umount+0x68/0x80
  [436.536]  do_syscall_64+0x2a5/0xf20
  [436.537]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [436.537] RIP: 0033:0x7fe5906b6217
  [436.538] Code: 0d 00 f7 (...)
  [436.540] RSP: 002b:00007ffcd87a61f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  [436.541] RAX: 0000000000000000 RBX: 00005618b9ecadc8 RCX: 00007fe5906b6217
  [436.541] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005618b9ecb100
  [436.542] RBP: 0000000000000000 R08: 00007ffcd87a4fe0 R09: 00000000ffffffff
  [436.544] R10: 0000000000000103 R11: 0000000000000246 R12: 00007fe59081626c
  [436.544] R13: 00005618b9ecb100 R14: 0000000000000000 R15: 00005618b9ecacc0
  [436.545]  </TASK>
  [436.545] ---[ end trace 0000000000000000 ]---

Fix this by changing the qgroup ioctls to use start transaction instead of
joining so that proper space is reserved for the delayed refs generated
for the updates to the quota root. This way we don't get any transaction
abort.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: check for NULL root after calls to btrfs_csum_root()
Filipe Manana [Sun, 8 Feb 2026 19:43:01 +0000 (19:43 +0000)] 
btrfs: check for NULL root after calls to btrfs_csum_root()

btrfs_csum_root() can return a NULL pointer in case the root we are
looking for is not in the rb tree that tracks roots. So add checks to
every caller that is missing such check to log a message and return
an error.

Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/20260208161657.3972997-1-clm@meta.com/
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: check for NULL root after calls to btrfs_extent_root()
Filipe Manana [Sun, 8 Feb 2026 19:24:16 +0000 (19:24 +0000)] 
btrfs: check for NULL root after calls to btrfs_extent_root()

btrfs_extent_root() can return a NULL pointer in case the root we are
looking for is not in the rb tree that tracks roots. So add checks to
every caller that is missing such check to log a message and return
an error. The same applies to callers of btrfs_block_group_root(),
since it calls btrfs_extent_root().

Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/20260208161657.3972997-1-clm@meta.com/
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: tree-checker: fix misleading root drop_level error message
ZhengYuan Huang [Thu, 12 Mar 2026 00:33:21 +0000 (08:33 +0800)] 
btrfs: tree-checker: fix misleading root drop_level error message

Fix tree-checker error message to report "invalid root drop_level"
instead of the misleading "invalid root level".

Fixes: 259ee7754b67 ("btrfs: tree-checker: Add ROOT_ITEM check")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: ZhengYuan Huang <gality369@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: log new dentries when logging parent dir of a conflicting inode
Filipe Manana [Tue, 3 Mar 2026 16:57:43 +0000 (16:57 +0000)] 
btrfs: log new dentries when logging parent dir of a conflicting inode

If we log the parent directory of a conflicting inode, we are not logging
the new dentries of the directory, so when we finish we have the parent
directory's inode marked as logged but we did not log its new dentries.
As a consequence if the parent directory is explicitly fsynced later and
it does not have any new changes since we logged it, the fsync is a no-op
and after a power failure the new dentries are missing.

Example scenario:

  $ mkdir foo

  $ sync

  $rmdir foo

  $ mkdir dir1
  $ mkdir dir2

  # A file with the same name and parent as the directory we just deleted
  # and was persisted in a past transaction. So the deleted directory's
  # inode is a conflicting inode of this new file's inode.
  $ touch foo

  $ ln foo dir2/link

  # The fsync on dir2 will log the parent directory (".") because the
  # conflicting inode (deleted directory) does not exists anymore, but it
  # it does not log its new dentries (dir1).
  $ xfs_io -c "fsync" dir2

  # This fsync on the parent directory is no-op, since the previous fsync
  # logged it (but without logging its new dentries).
  $ xfs_io -c "fsync" .

  <power failure>

  # After log replay dir1 is missing.

Fix this by ensuring we log new dir dentries whenever we log the parent
directory of a no longer existing conflicting inode.

A test case for fstests will follow soon.

Reported-by: Vyacheslav Kovalevsky <slava.kovalevskiy.2014@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/182055fa-e9ce-4089-9f5f-4b8a23e8dd91@gmail.com/
Fixes: a3baaf0d786e ("Btrfs: fix fsync after succession of renames and unlink/rmdir")
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: don't take device_list_mutex when querying zone info
Johannes Thumshirn [Tue, 3 Mar 2026 10:53:46 +0000 (11:53 +0100)] 
btrfs: don't take device_list_mutex when querying zone info

Shin'ichiro reported sporadic hangs when running generic/013 in our CI
system. When enabling lockdep, there is a lockdep splat when calling
btrfs_get_dev_zone_info_all_devices() in the mount path that can be
triggered by i.e. generic/013:

  ======================================================
  WARNING: possible circular locking dependency detected
  7.0.0-rc1+ #355 Not tainted
  ------------------------------------------------------
  mount/1043 is trying to acquire lock:
  ffff8881020b5470 (&vblk->vdev_mutex){+.+.}-{4:4}, at: virtblk_report_zones+0xda/0x430

  but task is already holding lock:
  ffff888102a738e0 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: btrfs_get_dev_zone_info_all_devices+0x45/0x90

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #4 (&fs_devs->device_list_mutex){+.+.}-{4:4}:
 __mutex_lock+0xa3/0x1360
 btrfs_create_pending_block_groups+0x1f4/0x9d0
 __btrfs_end_transaction+0x3e/0x2e0
 btrfs_zoned_reserve_data_reloc_bg+0x2f8/0x390
 open_ctree+0x1934/0x23db
 btrfs_get_tree.cold+0x105/0x26c
 vfs_get_tree+0x28/0xb0
 __do_sys_fsconfig+0x324/0x680
 do_syscall_64+0x92/0x4f0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #3 (btrfs_trans_num_extwriters){++++}-{0:0}:
 join_transaction+0xc2/0x5c0
 start_transaction+0x17c/0xbc0
 btrfs_zoned_reserve_data_reloc_bg+0x2b4/0x390
 open_ctree+0x1934/0x23db
 btrfs_get_tree.cold+0x105/0x26c
 vfs_get_tree+0x28/0xb0
 __do_sys_fsconfig+0x324/0x680
 do_syscall_64+0x92/0x4f0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #2 (btrfs_trans_num_writers){++++}-{0:0}:
 lock_release+0x163/0x4b0
 __btrfs_end_transaction+0x1c7/0x2e0
 btrfs_dirty_inode+0x6f/0xd0
 touch_atime+0xe5/0x2c0
 btrfs_file_mmap_prepare+0x65/0x90
 __mmap_region+0x4b9/0xf00
 mmap_region+0xf7/0x120
 do_mmap+0x43d/0x610
 vm_mmap_pgoff+0xd6/0x190
 ksys_mmap_pgoff+0x7e/0xc0
 do_syscall_64+0x92/0x4f0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #1 (&mm->mmap_lock){++++}-{4:4}:
 __might_fault+0x68/0xa0
 _copy_to_user+0x22/0x70
 blkdev_copy_zone_to_user+0x22/0x40
 virtblk_report_zones+0x282/0x430
 blkdev_report_zones_ioctl+0xfd/0x130
 blkdev_ioctl+0x20f/0x2c0
 __x64_sys_ioctl+0x86/0xd0
 do_syscall_64+0x92/0x4f0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #0 (&vblk->vdev_mutex){+.+.}-{4:4}:
 __lock_acquire+0x1522/0x2680
 lock_acquire+0xd5/0x2f0
 __mutex_lock+0xa3/0x1360
 virtblk_report_zones+0xda/0x430
 blkdev_report_zones_cached+0x162/0x190
 btrfs_get_dev_zones+0xdc/0x2e0
 btrfs_get_dev_zone_info+0x219/0xe80
 btrfs_get_dev_zone_info_all_devices+0x62/0x90
 open_ctree+0x1200/0x23db
 btrfs_get_tree.cold+0x105/0x26c
 vfs_get_tree+0x28/0xb0
 __do_sys_fsconfig+0x324/0x680
 do_syscall_64+0x92/0x4f0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

  other info that might help us debug this:

  Chain exists of:
    &vblk->vdev_mutex --> btrfs_trans_num_extwriters --> &fs_devs->device_list_mutex

   Possible unsafe locking scenario:

 CPU0                    CPU1
 ----                    ----
    lock(&fs_devs->device_list_mutex);
 lock(btrfs_trans_num_extwriters);
 lock(&fs_devs->device_list_mutex);
    lock(&vblk->vdev_mutex);

   *** DEADLOCK ***

  3 locks held by mount/1043:
   #0: ffff88811063e878 (&fc->uapi_mutex){+.+.}-{4:4}, at: __do_sys_fsconfig+0x2ae/0x680
   #1: ffff88810cb9f0e8 (&type->s_umount_key#31/1){+.+.}-{4:4}, at: alloc_super+0xc0/0x3e0
   #2: ffff888102a738e0 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: btrfs_get_dev_zone_info_all_devices+0x45/0x90

  stack backtrace:
  CPU: 2 UID: 0 PID: 1043 Comm: mount Not tainted 7.0.0-rc1+ #355 PREEMPT(full)
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-9.fc43 06/10/2025
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5b/0x80
   print_circular_bug.cold+0x18d/0x1d8
   check_noncircular+0x10d/0x130
   __lock_acquire+0x1522/0x2680
   ? vmap_small_pages_range_noflush+0x3ef/0x820
   lock_acquire+0xd5/0x2f0
   ? virtblk_report_zones+0xda/0x430
   ? lock_is_held_type+0xcd/0x130
   __mutex_lock+0xa3/0x1360
   ? virtblk_report_zones+0xda/0x430
   ? virtblk_report_zones+0xda/0x430
   ? __pfx_copy_zone_info_cb+0x10/0x10
   ? virtblk_report_zones+0xda/0x430
   virtblk_report_zones+0xda/0x430
   ? __pfx_copy_zone_info_cb+0x10/0x10
   blkdev_report_zones_cached+0x162/0x190
   ? __pfx_copy_zone_info_cb+0x10/0x10
   btrfs_get_dev_zones+0xdc/0x2e0
   btrfs_get_dev_zone_info+0x219/0xe80
   btrfs_get_dev_zone_info_all_devices+0x62/0x90
   open_ctree+0x1200/0x23db
   btrfs_get_tree.cold+0x105/0x26c
   ? rcu_is_watching+0x18/0x50
   vfs_get_tree+0x28/0xb0
   __do_sys_fsconfig+0x324/0x680
   do_syscall_64+0x92/0x4f0
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
  RIP: 0033:0x7f615e27a40e
  RSP: 002b:00007fff11b18fb8 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
  RAX: ffffffffffffffda RBX: 000055572e92ab10 RCX: 00007f615e27a40e
  RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
  RBP: 00007fff11b19100 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  R13: 000055572e92bc40 R14: 00007f615e3faa60 R15: 000055572e92bd08
   </TASK>

Don't hold the device_list_mutex while calling into
btrfs_get_dev_zone_info() in btrfs_get_dev_zone_info_all_devices() to
mitigate the issue. This is safe, as no other thread can touch the device
list at the moment of execution.

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2 months agobtrfs: pass 'verbose' parameter to btrfs_relocate_block_group
Johannes Thumshirn [Fri, 27 Feb 2026 13:12:24 +0000 (14:12 +0100)] 
btrfs: pass 'verbose' parameter to btrfs_relocate_block_group

Function `btrfs_relocate_chunk()` always passes verbose=true to
`btrfs_relocate_block_group()` instead of the `verbose` parameter passed
into it by it's callers.

While user initiated rebalancing should be logged in the Kernel's log
buffer. This causes excessive log spamming from automatic rebalancing,
e.g. on zoned filesystems running low on usable space.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove duplicated definition of btrfs_printk_in_rcu()
Filipe Manana [Fri, 27 Feb 2026 12:09:47 +0000 (12:09 +0000)] 
btrfs: remove duplicated definition of btrfs_printk_in_rcu()

It's defined twice in a row for the !CONFIG_PRINTK case, so remove one
of the duplicates.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove unnecessary transaction abort in the received subvol ioctl
Filipe Manana [Fri, 27 Feb 2026 00:05:08 +0000 (00:05 +0000)] 
btrfs: remove unnecessary transaction abort in the received subvol ioctl

If we fail to remove an item from the uuid tree, we don't need to abort
the transaction since we have not done any change before. So remove that
transaction abort.

Reviewed-by: Anand Jain <asj@kernel.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: abort transaction on failure to update root in the received subvol ioctl
Filipe Manana [Fri, 27 Feb 2026 00:02:33 +0000 (00:02 +0000)] 
btrfs: abort transaction on failure to update root in the received subvol ioctl

If we failed to update the root we don't abort the transaction, which is
wrong since we already used the transaction to remove an item from the
uuid tree.

Fixes: dd5f9615fc5c ("Btrfs: maintain subvolume items in the UUID tree")
CC: stable@vger.kernel.org # 3.12+
Reviewed-by: Anand Jain <asj@kernel.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix transaction abort on set received ioctl due to item overflow
Filipe Manana [Thu, 26 Feb 2026 23:41:07 +0000 (23:41 +0000)] 
btrfs: fix transaction abort on set received ioctl due to item overflow

If the set received ioctl fails due to an item overflow when attempting to
add the BTRFS_UUID_KEY_RECEIVED_SUBVOL we have to abort the transaction
since we did some metadata updates before.

This means that if a user calls this ioctl with the same received UUID
field for a lot of subvolumes, we will hit the overflow, trigger the
transaction abort and turn the filesystem into RO mode. A malicious user
could exploit this, and this ioctl does not even requires that a user
has admin privileges (CAP_SYS_ADMIN), only that he/she owns the subvolume.

Fix this by doing an early check for item overflow before starting a
transaction. This is also race safe because we are holding the subvol_sem
semaphore in exclusive (write) mode.

A test case for fstests will follow soon.

Fixes: dd5f9615fc5c ("Btrfs: maintain subvolume items in the UUID tree")
CC: stable@vger.kernel.org # 3.12+
Reviewed-by: Anand Jain <asj@kernel.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix transaction abort when snapshotting received subvolumes
Filipe Manana [Mon, 23 Feb 2026 16:19:31 +0000 (16:19 +0000)] 
btrfs: fix transaction abort when snapshotting received subvolumes

Currently a user can trigger a transaction abort by snapshotting a
previously received snapshot a bunch of times until we reach a
BTRFS_UUID_KEY_RECEIVED_SUBVOL item overflow (the maximum item size we
can store in a leaf). This is very likely not common in practice, but
if it happens, it turns the filesystem into RO mode. The snapshot, send
and set_received_subvol and subvol_setflags (used by receive) don't
require CAP_SYS_ADMIN, just inode_owner_or_capable(). A malicious user
could use this to turn a filesystem into RO mode and disrupt a system.

Reproducer script:

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/sdi
  MNT=/mnt/sdi

  # Use smallest node size to make the test faster.
  mkfs.btrfs -f --nodesize 4K $DEV
  mount $DEV $MNT

  # Create a subvolume and set it to RO so that it can be used for send.
  btrfs subvolume create $MNT/sv
  touch $MNT/sv/foo
  btrfs property set $MNT/sv ro true

  # Send and receive the subvolume into snaps/sv.
  mkdir $MNT/snaps
  btrfs send $MNT/sv | btrfs receive $MNT/snaps

  # Now snapshot the received subvolume, which has a received_uuid, a
  # lot of times to trigger the leaf overflow.
  total=500
  for ((i = 1; i <= $total; i++)); do
      echo -ne "\rCreating snapshot $i/$total"
      btrfs subvolume snapshot -r $MNT/snaps/sv $MNT/snaps/sv_$i > /dev/null
  done
  echo

  umount $MNT

When running the test:

  $ ./test.sh
  (...)
  Create subvolume '/mnt/sdi/sv'
  At subvol /mnt/sdi/sv
  At subvol sv
  Creating snapshot 496/500ERROR: Could not create subvolume: Value too large for defined data type
  Creating snapshot 497/500ERROR: Could not create subvolume: Read-only file system
  Creating snapshot 498/500ERROR: Could not create subvolume: Read-only file system
  Creating snapshot 499/500ERROR: Could not create subvolume: Read-only file system
  Creating snapshot 500/500ERROR: Could not create subvolume: Read-only file system

And in dmesg/syslog:

  $ dmesg
  (...)
  [251067.627338] BTRFS warning (device sdi): insert uuid item failed -75 (0x4628b21c4ac8d898, 0x2598bee2b1515c91) type 252!
  [251067.629212] ------------[ cut here ]------------
  [251067.630033] BTRFS: Transaction aborted (error -75)
  [251067.630871] WARNING: fs/btrfs/transaction.c:1907 at create_pending_snapshot.cold+0x52/0x465 [btrfs], CPU#10: btrfs/615235
  [251067.632851] Modules linked in: btrfs dm_zero (...)
  [251067.644071] CPU: 10 UID: 0 PID: 615235 Comm: btrfs Tainted: G        W           6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
  [251067.646165] Tainted: [W]=WARN
  [251067.646733] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [251067.648735] RIP: 0010:create_pending_snapshot.cold+0x55/0x465 [btrfs]
  [251067.649984] Code: f0 48 0f (...)
  [251067.653313] RSP: 0018:ffffce644908fae8 EFLAGS: 00010292
  [251067.653987] RAX: 00000000ffffff01 RBX: ffff8e5639e63a80 RCX: 00000000ffffffd3
  [251067.655042] RDX: ffff8e53faa76b00 RSI: 00000000ffffffb5 RDI: ffffffffc0919750
  [251067.656077] RBP: ffffce644908fbd8 R08: 0000000000000000 R09: ffffce644908f820
  [251067.657068] R10: ffff8e5adc1fffa8 R11: 0000000000000003 R12: ffff8e53c0431bd0
  [251067.658050] R13: ffff8e5414593600 R14: ffff8e55efafd000 R15: 00000000ffffffb5
  [251067.659019] FS:  00007f2a4944b3c0(0000) GS:ffff8e5b27dae000(0000) knlGS:0000000000000000
  [251067.660115] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [251067.660943] CR2: 00007ffc5aa57898 CR3: 00000005813a2003 CR4: 0000000000370ef0
  [251067.661972] Call Trace:
  [251067.662292]  <TASK>
  [251067.662653]  create_pending_snapshots+0x97/0xc0 [btrfs]
  [251067.663413]  btrfs_commit_transaction+0x26e/0xc00 [btrfs]
  [251067.664257]  ? btrfs_qgroup_convert_reserved_meta+0x35/0x390 [btrfs]
  [251067.665238]  ? _raw_spin_unlock+0x15/0x30
  [251067.665837]  ? record_root_in_trans+0xa2/0xd0 [btrfs]
  [251067.666531]  btrfs_mksubvol+0x330/0x580 [btrfs]
  [251067.667145]  btrfs_mksnapshot+0x74/0xa0 [btrfs]
  [251067.667827]  __btrfs_ioctl_snap_create+0x194/0x1d0 [btrfs]
  [251067.668595]  btrfs_ioctl_snap_create_v2+0x107/0x130 [btrfs]
  [251067.669479]  btrfs_ioctl+0x1580/0x2690 [btrfs]
  [251067.670093]  ? count_memcg_events+0x6d/0x180
  [251067.670849]  ? handle_mm_fault+0x1a0/0x2a0
  [251067.671652]  __x64_sys_ioctl+0x92/0xe0
  [251067.672406]  do_syscall_64+0x50/0xf20
  [251067.673129]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [251067.674096] RIP: 0033:0x7f2a495648db
  [251067.674812] Code: 00 48 89 (...)
  [251067.678227] RSP: 002b:00007ffc5aa57840 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [251067.679691] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f2a495648db
  [251067.681145] RDX: 00007ffc5aa588b0 RSI: 0000000050009417 RDI: 0000000000000004
  [251067.682511] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
  [251067.683842] R10: 000000000000000a R11: 0000000000000246 R12: 00007ffc5aa59910
  [251067.685176] R13: 00007ffc5aa588b0 R14: 0000000000000004 R15: 0000000000000006
  [251067.686524]  </TASK>
  [251067.686972] ---[ end trace 0000000000000000 ]---
  [251067.687890] BTRFS: error (device sdi state A) in create_pending_snapshot:1907: errno=-75 unknown
  [251067.689049] BTRFS info (device sdi state EA): forced readonly
  [251067.689054] BTRFS warning (device sdi state EA): Skipping commit of aborted transaction.
  [251067.690119] BTRFS: error (device sdi state EA) in cleanup_transaction:2043: errno=-75 unknown
  [251067.702028] BTRFS info (device sdi state EA): last unmount of filesystem 46dc3975-30a2-4a69-a18f-418b859cccda

Fix this by ignoring -EOVERFLOW errors from btrfs_uuid_tree_add() in the
snapshot creation code when attempting to add the
BTRFS_UUID_KEY_RECEIVED_SUBVOL item. This is OK because it's not critical
and we are still able to delete the snapshot, as snapshot/subvolume
deletion ignores if a BTRFS_UUID_KEY_RECEIVED_SUBVOL is missing (see
inode.c:btrfs_delete_subvolume()). As for send/receive, we can still do
send/receive operations since it always peeks the first root ID in the
existing BTRFS_UUID_KEY_RECEIVED_SUBVOL (it could peek any since all
snapshots have the same content), and even if the key is missing, it
falls back to searching by BTRFS_UUID_KEY_SUBVOL key.

A test case for fstests will be sent soon.

Fixes: dd5f9615fc5c ("Btrfs: maintain subvolume items in the UUID tree")
CC: stable@vger.kernel.org # 3.12+
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: fix transaction abort on file creation due to name hash collision
Filipe Manana [Thu, 26 Feb 2026 11:05:43 +0000 (11:05 +0000)] 
btrfs: fix transaction abort on file creation due to name hash collision

If we attempt to create several files with names that result in the same
hash, we have to pack them in same dir item and that has a limit inherent
to the leaf size. However if we reach that limit, we trigger a transaction
abort and turns the filesystem into RO mode. This allows for a malicious
user to disrupt a system, without the need to have administration
privileges/capabilities.

Reproducer:

  $ cat exploit-hash-collisions.sh
  #!/bin/bash

  DEV=/dev/sdi
  MNT=/mnt/sdi

  # Use smallest node size to make the test faster and require fewer file
  # names that result in hash collision.
  mkfs.btrfs -f --nodesize 4K $DEV
  mount $DEV $MNT

  # List of names that result in the same crc32c hash for btrfs.
  declare -a names=(
   'foobar'
   '%a8tYkxfGMLWRGr55QSeQc4PBNH9PCLIvR6jZnkDtUUru1t@RouaUe_L:@xGkbO3nCwvLNYeK9vhE628gss:T$yZjZ5l-Nbd6CbC$M=hqE-ujhJICXyIxBvYrIU9-TDC'
   'AQci3EUB%shMsg-N%frgU:02ByLs=IPJU0OpgiWit5nexSyxZDncY6WB:=zKZuk5Zy0DD$Ua78%MelgBuMqaHGyKsJUFf9s=UW80PcJmKctb46KveLSiUtNmqrMiL9-Y0I_l5Fnam04CGIg=8@U:Z'
   'CvVqJpJzueKcuA$wqwePfyu7VxuWNN3ho$p0zi2H8QFYK$7YlEqOhhb%:hHgjhIjW5vnqWHKNP4'
   'ET:vk@rFU4tsvMB0$C_p=xQHaYZjvoF%-BTc%wkFW8yaDAPcCYoR%x$FH5O:'
   'HwTon%v7SGSP4FE08jBwwiu5aot2CFKXHTeEAa@38fUcNGOWvE@Mz6WBeDH_VooaZ6AgsXPkVGwy9l@@ZbNXabUU9csiWrrOp0MWUdfi$EZ3w9GkIqtz7I_eOsByOkBOO'
   'Ij%2VlFGXSuPvxJGf5UWy6O@1svxGha%b@=%wjkq:CIgE6u7eJOjmQY5qTtxE2Rjbis9@us'
   'KBkjG5%9R8K9sOG8UTnAYjxLNAvBmvV5vz3IiZaPmKuLYO03-6asI9lJ_j4@6Xo$KZicaLWJ3Pv8XEwVeUPMwbHYWwbx0pYvNlGMO9F:ZhHAwyctnGy%_eujl%WPd4U2BI7qooOSr85J-C2V$LfY'
   'NcRfDfuUQ2=zP8K3CCF5dFcpfiOm6mwenShsAb_F%n6GAGC7fT2JFFn:c35X-3aYwoq7jNX5$ZJ6hI3wnZs$7KgGi7wjulffhHNUxAT0fRRLF39vJ@NvaEMxsMO'
   'Oj42AQAEzRoTxa5OuSKIr=A_lwGMy132v4g3Pdq1GvUG9874YseIFQ6QU'
   'Ono7avN5GjC:_6dBJ_'
   'WHmN2gnmaN-9dVDy4aWo:yNGFzz8qsJyJhWEWcud7$QzN2D9R0efIWWEdu5kwWr73NZm4=@CoCDxrrZnRITr-kGtU_cfW2:%2_am'
   'WiFnuTEhAG9FEC6zopQmj-A-$LDQ0T3WULz%ox3UZAPybSV6v1Z$b4L_XBi4M4BMBtJZpz93r9xafpB77r:lbwvitWRyo$odnAUYlYMmU4RvgnNd--e=I5hiEjGLETTtaScWlQp8mYsBovZwM2k'
   'XKyH=OsOAF3p%uziGF_ZVr$ivrvhVgD@1u%5RtrV-gl_vqAwHkK@x7YwlxX3qT6WKKQ%PR56NrUBU2dOAOAdzr2=5nJuKPM-T-$ZpQfCL7phxQbUcb:BZOTPaFExc-qK-gDRCDW2'
   'd3uUR6OFEwZr%ns1XH_@tbxA@cCPmbBRLdyh7p6V45H$P2$F%w0RqrD3M0g8aGvWpoTFMiBdOTJXjD:JF7=h9a_43xBywYAP%r$SPZi%zDg%ql-KvkdUCtF9OLaQlxmd'
   'ePTpbnit%hyNm@WELlpKzNZYOzOTf8EQ$sEfkMy1VOfIUu3coyvIr13-Y7Sv5v-Ivax2Go_GQRFMU1b3362nktT9WOJf3SpT%z8sZmM3gvYQBDgmKI%%RM-G7hyrhgYflOw%z::ZRcv5O:lDCFm'
   'evqk743Y@dvZAiG5J05L_ROFV@$2%rVWJ2%3nxV72-W7$e$-SK3tuSHA2mBt$qloC5jwNx33GmQUjD%akhBPu=VJ5g$xhlZiaFtTrjeeM5x7dt4cHpX0cZkmfImndYzGmvwQG:$euFYmXn$_2rA9mKZ'
   'gkgUtnihWXsZQTEkrMAWIxir09k3t7jk_IK25t1:cy1XWN0GGqC%FrySdcmU7M8MuPO_ppkLw3=Dfr0UuBAL4%GFk2$Ma10V1jDRGJje%Xx9EV2ERaWKtjpwiZwh0gCSJsj5UL7CR8RtW5opCVFKGGy8Cky'
   'hNgsG_8lNRik3PvphqPm0yEH3P%%fYG:kQLY=6O-61Wa6nrV_WVGR6TLB09vHOv%g4VQRP8Gzx7VXUY1qvZyS'
   'isA7JVzN12xCxVPJZ_qoLm-pTBuhjjHMvV7o=F:EaClfYNyFGlsfw-Kf%uxdqW-kwk1sPl2vhbjyHU1A6$hz'
   'kiJ_fgcdZFDiOptjgH5PN9-PSyLO4fbk_:u5_2tz35lV_iXiJ6cx7pwjTtKy-XGaQ5IefmpJ4N_ZqGsqCsKuqOOBgf9LkUdffHet@Wu'
   'lvwtxyhE9:%Q3UxeHiViUyNzJsy:fm38pg_b6s25JvdhOAT=1s0$pG25x=LZ2rlHTszj=gN6M4zHZYr_qrB49i=pA--@WqWLIuX7o1S_SfS@2FSiUZN'
   'rC24cw3UBDZ=5qJBUMs9e$=S4Y94ni%Z8639vnrGp=0Hv4z3dNFL0fBLmQ40=EYIY:Z=SLc@QLMSt2zsss2ZXrP7j4='
   'uwGl2s-fFrf@GqS=DQqq2I0LJSsOmM%xzTjS:lzXguE3wChdMoHYtLRKPvfaPOZF2fER@j53evbKa7R%A7r4%YEkD=kicJe@SFiGtXHbKe4gCgPAYbnVn'
   'UG37U6KKua2bgc:IHzRs7BnB6FD:2Mt5Cc5NdlsW%$1tyvnfz7S27FvNkroXwAW:mBZLA1@qa9WnDbHCDmQmfPMC9z-Eq6QT0jhhPpqyymaD:R02ghwYo%yx7SAaaq-:x33LYpei$5g8DMl3C'
   'y2vjek0FE1PDJC0qpfnN:x8k2wCFZ9xiUF2ege=JnP98R%wxjKkdfEiLWvQzmnW'
   '8-HCSgH5B%K7P8_jaVtQhBXpBk:pE-$P7ts58U0J@iR9YZntMPl7j$s62yAJO@_9eanFPS54b=UTw$94C-t=HLxT8n6o9P=QnIxq-f1=Ne2dvhe6WbjEQtc'
   'YPPh:IFt2mtR6XWSmjHptXL_hbSYu8bMw-JP8@PNyaFkdNFsk$M=xfL6LDKCDM-mSyGA_2MBwZ8Dr4=R1D%7-mCaaKGxb990jzaagRktDTyp'
   '9hD2ApKa_t_7x-a@GCG28kY:7$M@5udI1myQ$x5udtggvagmCQcq9QXWRC5hoB0o-_zHQUqZI5rMcz_kbMgvN5jr63LeYA4Cj-c6F5Ugmx6DgVf@2Jqm%MafecpgooqreJ53P-QTS'
  )

  # Now create files with all those names in the same parent directory.
  # It should not fail since a 4K leaf has enough space for them.
  for name in "${names[@]}"; do
       touch $MNT/$name
  done

  # Now add one more file name that causes a crc32c hash collision.
  # This should fail, but it should not turn the filesystem into RO mode
  # (which could be exploited by malicious users) due to a transaction
  # abort.
  touch $MNT/'W6tIm-VK2@BGC@IBfcgg6j_p:pxp_QUqtWpGD5Ok_GmijKOJJt'

  # Check that we are able to create another file, with a name that does not cause
  # a crc32c hash collision.
  echo -n "hello world" > $MNT/baz

  # Unmount and mount again, verify file baz exists and with the right content.
  umount $MNT
  mount $DEV $MNT
  echo "File baz content: $(cat $MNT/baz)"

  umount $MNT

When running the reproducer:

  $ ./exploit-hash-collisions.sh
  (...)
  touch: cannot touch '/mnt/sdi/W6tIm-VK2@BGC@IBfcgg6j_p:pxp_QUqtWpGD5Ok_GmijKOJJt': Value too large for defined data type
  ./exploit-hash-collisions.sh: line 57: /mnt/sdi/baz: Read-only file system
  cat: /mnt/sdi/baz: No such file or directory
  File baz content:

And the transaction abort stack trace in dmesg/syslog:

  $ dmesg
  (...)
  [758240.509761] ------------[ cut here ]------------
  [758240.510668] BTRFS: Transaction aborted (error -75)
  [758240.511577] WARNING: fs/btrfs/inode.c:6854 at btrfs_create_new_inode+0x805/0xb50 [btrfs], CPU#6: touch/888644
  [758240.513513] Modules linked in: btrfs dm_zero (...)
  [758240.523221] CPU: 6 UID: 0 PID: 888644 Comm: touch Tainted: G        W           6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
  [758240.524621] Tainted: [W]=WARN
  [758240.525037] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [758240.526331] RIP: 0010:btrfs_create_new_inode+0x80b/0xb50 [btrfs]
  [758240.527093] Code: 0f 82 cf (...)
  [758240.529211] RSP: 0018:ffffce64418fbb48 EFLAGS: 00010292
  [758240.529935] RAX: 00000000ffffffd3 RBX: 0000000000000000 RCX: 00000000ffffffb5
  [758240.531040] RDX: 0000000d04f33e06 RSI: 00000000ffffffb5 RDI: ffffffffc0919dd0
  [758240.531920] RBP: ffffce64418fbc10 R08: 0000000000000000 R09: 00000000ffffffb5
  [758240.532928] R10: 0000000000000000 R11: ffff8e52c0000000 R12: ffff8e53eee7d0f0
  [758240.533818] R13: ffff8e57f70932a0 R14: ffff8e5417629568 R15: 0000000000000000
  [758240.534664] FS:  00007f1959a2a740(0000) GS:ffff8e5b27cae000(0000) knlGS:0000000000000000
  [758240.535821] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [758240.536644] CR2: 00007f1959b10ce0 CR3: 000000012a2cc005 CR4: 0000000000370ef0
  [758240.537517] Call Trace:
  [758240.537828]  <TASK>
  [758240.538099]  btrfs_create_common+0xbf/0x140 [btrfs]
  [758240.538760]  path_openat+0x111a/0x15b0
  [758240.539252]  do_filp_open+0xc2/0x170
  [758240.539699]  ? preempt_count_add+0x47/0xa0
  [758240.540200]  ? __virt_addr_valid+0xe4/0x1a0
  [758240.540800]  ? __check_object_size+0x1b3/0x230
  [758240.541661]  ? alloc_fd+0x118/0x180
  [758240.542315]  do_sys_openat2+0x70/0xd0
  [758240.543012]  __x64_sys_openat+0x50/0xa0
  [758240.543723]  do_syscall_64+0x50/0xf20
  [758240.544462]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [758240.545397] RIP: 0033:0x7f1959abc687
  [758240.546019] Code: 48 89 fa (...)
  [758240.548522] RSP: 002b:00007ffe16ff8690 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
  [758240.566278] RAX: ffffffffffffffda RBX: 00007f1959a2a740 RCX: 00007f1959abc687
  [758240.567068] RDX: 0000000000000941 RSI: 00007ffe16ffa333 RDI: ffffffffffffff9c
  [758240.567860] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
  [758240.568707] R10: 00000000000001b6 R11: 0000000000000202 R12: 0000561eec7c4b90
  [758240.569712] R13: 0000561eec7c311f R14: 00007ffe16ffa333 R15: 0000000000000000
  [758240.570758]  </TASK>
  [758240.571040] ---[ end trace 0000000000000000 ]---
  [758240.571681] BTRFS: error (device sdi state A) in btrfs_create_new_inode:6854: errno=-75 unknown
  [758240.572899] BTRFS info (device sdi state EA): forced readonly

Fix this by checking for hash collision, and if the adding a new name is
possible, early in btrfs_create_new_inode() before we do any tree updates,
so that we don't need to abort the transaction if we cannot add the new
name due to the leaf size limit.

A test case for fstests will be sent soon.

Fixes: caae78e03234 ("btrfs: move common inode creation code into btrfs_create_new_inode()")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: read key again after incrementing slot in move_existing_remaps()
Mark Harmstone [Wed, 25 Feb 2026 10:36:06 +0000 (10:36 +0000)] 
btrfs: read key again after incrementing slot in move_existing_remaps()

Fix move_existing_remaps() so that if we increment the slot because the
key we encounter isn't a REMAP_BACKREF, we don't reuse the objectid and
offset of the old item.

Link: https://lore.kernel.org/linux-btrfs/20260125123908.2096548-1-clm@meta.com/
Reported-by: Chris Mason <clm@fb.com>
Fixes: bbea42dfb91f ("btrfs: move existing remaps before relocating block group")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: add missing RCU unlock in error path in try_release_subpage_extent_buffer()
Bart Van Assche [Wed, 25 Feb 2026 19:59:58 +0000 (11:59 -0800)] 
btrfs: add missing RCU unlock in error path in try_release_subpage_extent_buffer()

Call rcu_read_lock() before exiting the loop in
try_release_subpage_extent_buffer() because there is a rcu_read_unlock()
call past the loop.

This has been detected by the Clang thread-safety analyzer.

Fixes: ad580dfa388f ("btrfs: fix subpage deadlock in try_release_subpage_extent_buffer()")
CC: stable@vger.kernel.org # 6.18+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: set BTRFS_ROOT_ORPHAN_CLEANUP during subvol create
Boris Burkov [Tue, 24 Feb 2026 22:25:35 +0000 (14:25 -0800)] 
btrfs: set BTRFS_ROOT_ORPHAN_CLEANUP during subvol create

We have recently observed a number of subvolumes with broken dentries.
ls-ing the parent dir looks like:

drwxrwxrwt 1 root root 16 Jan 23 16:49 .
drwxr-xr-x 1 root root 24 Jan 23 16:48 ..
d????????? ? ?    ?     ?            ? broken_subvol

and similarly stat-ing the file fails.

In this state, deleting the subvol fails with ENOENT, but attempting to
create a new file or subvol over it errors out with EEXIST and even
aborts the fs. Which leaves us a bit stuck.

dmesg contains a single notable error message reading:
"could not do orphan cleanup -2"

2 is ENOENT and the error comes from the failure handling path of
btrfs_orphan_cleanup(), with the stack leading back up to
btrfs_lookup().

btrfs_lookup
btrfs_lookup_dentry
btrfs_orphan_cleanup // prints that message and returns -ENOENT

After some detailed inspection of the internal state, it became clear
that:
- there are no orphan items for the subvol
- the subvol is otherwise healthy looking, it is not half-deleted or
  anything, there is no drop progress, etc.
- the subvol was created a while ago and does the meaningful first
  btrfs_orphan_cleanup() call that sets BTRFS_ROOT_ORPHAN_CLEANUP much
  later.
- after btrfs_orphan_cleanup() fails, btrfs_lookup_dentry() returns -ENOENT,
  which results in a negative dentry for the subvolume via
  d_splice_alias(NULL, dentry), leading to the observed behavior. The
  bug can be mitigated by dropping the dentry cache, at which point we
  can successfully delete the subvolume if we want.

i.e.,
btrfs_lookup()
  btrfs_lookup_dentry()
    if (!sb_rdonly(inode->vfs_inode)->vfs_inode)
    btrfs_orphan_cleanup(sub_root)
      test_and_set_bit(BTRFS_ROOT_ORPHAN_CLEANUP)
      btrfs_search_slot() // finds orphan item for inode N
      ...
      prints "could not do orphan cleanup -2"
  if (inode == ERR_PTR(-ENOENT))
    inode = NULL;
  return d_splice_alias(NULL, dentry) // NEGATIVE DENTRY for valid subvolume

btrfs_orphan_cleanup() does test_and_set_bit(BTRFS_ROOT_ORPHAN_CLEANUP)
on the root when it runs, so it cannot run more than once on a given
root, so something else must run concurrently. However, the obvious
routes to deleting an orphan when nlinks goes to 0 should not be able to
run without first doing a lookup into the subvolume, which should run
btrfs_orphan_cleanup() and set the bit.

The final important observation is that create_subvol() calls
d_instantiate_new() but does not set BTRFS_ROOT_ORPHAN_CLEANUP, so if
the dentry cache gets dropped, the next lookup into the subvolume will
make a real call into btrfs_orphan_cleanup() for the first time. This
opens up the possibility of concurrently deleting the inode/orphan items
but most typical evict() paths will be holding a reference on the parent
dentry (child dentry holds parent->d_lockref.count via dget in
d_alloc(), released in __dentry_kill()) and prevent the parent from
being removed from the dentry cache.

The one exception is delayed iputs. Ordered extent creation calls
igrab() on the inode. If the file is unlinked and closed while those
refs are held, iput() in __dentry_kill() decrements i_count but does
not trigger eviction (i_count > 0). The child dentry is freed and the
subvol dentry's d_lockref.count drops to 0, making it evictable while
the inode is still alive.

Since there are two races (the race between writeback and unlink and
the race between lookup and delayed iputs), and there are too many moving
parts, the following three diagrams show the complete picture.
(Only the second and third are races)

Phase 1:
Create Subvol in dentry cache without BTRFS_ROOT_ORPHAN_CLEANUP set

btrfs_mksubvol()
  lookup_one_len()
    __lookup_slow()
      d_alloc_parallel()
        __d_alloc() // d_lockref.count = 1
  create_subvol(dentry)
    // doesn't touch the bit..
    d_instantiate_new(dentry, inode) // dentry in cache with d_lockref.count == 1

Phase 2:
Create a delayed iput for a file in the subvol but leave the subvol in
state where its dentry can be evicted (d_lockref.count == 0)

T1 (task)                    T2 (writeback)                   T3 (OE workqueue)

write() // dirty pages
                              btrfs_writepages()
                                btrfs_run_delalloc_range()
                                  cow_file_range()
                                    btrfs_alloc_ordered_extent()
                                      igrab() // i_count: 1 -> 2
btrfs_unlink_inode()
  btrfs_orphan_add()
close()
  __fput()
    dput()
      finish_dput()
        __dentry_kill()
          dentry_unlink_inode()
            iput() // 2 -> 1
          --parent->d_lockref.count // 1 -> 0; evictable
                                                                finish_ordered_fn()
                                                                  btrfs_finish_ordered_io()
                                                                    btrfs_put_ordered_extent()
                                                                      btrfs_add_delayed_iput()

Phase 3:
Once the delayed iput is pending and the subvol dentry is evictable,
the shrinker can free it, causing the next lookup to go through
btrfs_lookup() and call btrfs_orphan_cleanup() for the first time.
If the cleaner kthread processes the delayed iput concurrently, the
two race:

  T1 (shrinker)              T2 (cleaner kthread)                          T3 (lookup)

  super_cache_scan()
    prune_dcache_sb()
      __dentry_kill()
      // subvol dentry freed
                              btrfs_run_delayed_iputs()
                                iput()  // i_count -> 0
                                  evict()  // sets I_FREEING
                                    btrfs_evict_inode()
                                      // truncation loop
                                                                            btrfs_lookup()
                                                                              btrfs_lookup_dentry()
                                                                                btrfs_orphan_cleanup()
                                                                                  // first call (bit never set)
                                                                                  btrfs_iget()
                                                                                    // blocks on I_FREEING

                                      btrfs_orphan_del()
                                      // inode freed
                                                                                    // returns -ENOENT
                                                                                  btrfs_del_orphan_item()
                                                                                    // -ENOENT
                                                                                // "could not do orphan cleanup -2"
                                                                            d_splice_alias(NULL, dentry)
                                                                            // negative dentry for valid subvol

The most straightforward fix is to ensure the invariant that a dentry
for a subvolume can exist if and only if that subvolume has
BTRFS_ROOT_ORPHAN_CLEANUP set on its root (and is known to have no
orphans or ran btrfs_orphan_cleanup()).

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zoned: move btrfs_zoned_reserve_data_reloc_bg() after kthread start
Johannes Thumshirn [Tue, 24 Feb 2026 12:51:13 +0000 (13:51 +0100)] 
btrfs: zoned: move btrfs_zoned_reserve_data_reloc_bg() after kthread start

btrfs_zoned_reserve_data_reloc_bg() is called on each mount of a file
system and allocates a new block-group, to assign it to be the dedicated
relocation target, if no pre-existing usable block-group for this task is
found.

If for some reason the transaction is aborted, btrfs_end_transaction()
will wake up the transaction kthread. But the transaction kthread is not
yet initialized at the time btrfs_zoned_reserve_data_reloc_bg() is
called, leading to the following NULL-pointer dereference:

  RSP: 0018:ffffc9000c617c98 EFLAGS: 00010046
  RAX: 0000000000000000 RBX: 000000000000073c RCX: 0000000000000002
  RDX: 0000000000000001 RSI: 0000000000000003 RDI: 0000000000000001
  RBP: 0000000000000207 R08: ffffffff8223c71d R09: 0000000000000635
  R10: ffff888108588000 R11: 0000000000000003 R12: 0000000000000003
  R13: 000000000000073c R14: 0000000000000000 R15: ffff888114dd6000
  FS:  00007f2993745840(0000) GS:ffff8882b508d000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000000000000073c CR3: 0000000121a82006 CR4: 0000000000770eb0
  PKRU: 55555554
  Call Trace:
   <TASK>
   try_to_wake_up (./include/linux/spinlock.h:557 kernel/sched/core.c:4106)
   __btrfs_end_transaction (fs/btrfs/transaction.c:1115 (discriminator 2))
   btrfs_zoned_reserve_data_reloc_bg (fs/btrfs/zoned.c:2840)
   open_ctree (fs/btrfs/disk-io.c:3588)
   btrfs_get_tree.cold (fs/btrfs/super.c:982 fs/btrfs/super.c:1944 fs/btrfs/super.c:2087 fs/btrfs/super.c:2121)
   vfs_get_tree (fs/super.c:1752)
   __do_sys_fsconfig (fs/fsopen.c:231 fs/fsopen.c:295 fs/fsopen.c:473)
   do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)
  RIP: 0033:0x7f299392740e

Move the call to btrfs_zoned_reserve_data_reloc_bg() after the
transaction_kthread has been initialized to fix this problem.

Fixes: 694ce5e143d6 ("btrfs: zoned: reserve data_reloc block group on mount")
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: hold space_info->lock when clearing periodic reclaim ready
Sun YangKai [Mon, 9 Feb 2026 12:53:39 +0000 (20:53 +0800)] 
btrfs: hold space_info->lock when clearing periodic reclaim ready

btrfs_set_periodic_reclaim_ready() requires space_info->lock to be held,
as enforced by lockdep_assert_held(). However, btrfs_reclaim_sweep() was
calling it after do_reclaim_sweep() returns, at which point
space_info->lock is no longer held.

Fix this by explicitly acquiring space_info->lock before clearing the
periodic reclaim ready flag in btrfs_reclaim_sweep().

Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/20260208182556.891815-1-clm@meta.com/
Fixes: 19eff93dc738 ("btrfs: fix periodic reclaim condition")
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Sun YangKai <sunk67188@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: print-tree: add remap tree definitions
Mark Harmstone [Mon, 9 Feb 2026 18:00:14 +0000 (18:00 +0000)] 
btrfs: print-tree: add remap tree definitions

Add the definitions for the remap tree to print-tree.c, so that we get
more useful information if a tree is dumped to dmesg.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: check block group lookup in remove_range_from_remap_tree()
Mark Harmstone [Thu, 19 Feb 2026 14:30:59 +0000 (14:30 +0000)] 
btrfs: check block group lookup in remove_range_from_remap_tree()

Add a check in remove_range_from_remap_tree() after we call
btrfs_lookup_block_group(), to check if it is NULL. This shouldn't
happen, but if it does we at least get an error rather than a segfault.

Reported-by: Chris Mason <clm@fb.com>
Link: https://lore.kernel.org/linux-btrfs/20260125125129.2245240-1-clm@meta.com/
Fixes: 979e1dc3d69e ("btrfs: handle deletions from remapped block group")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix transaction handle leaks in btrfs_last_identity_remap_gone()
Mark Harmstone [Thu, 19 Feb 2026 14:16:02 +0000 (14:16 +0000)] 
btrfs: fix transaction handle leaks in btrfs_last_identity_remap_gone()

btrfs_abort_transaction(), unlike btrfs_commit_transaction(), doesn't
also free the transaction handle. Fix the instances in
btrfs_last_identity_remap_gone() where we're also leaking the
transaction on abort.

Reported-by: Chris Mason <clm@fb.com>
Link: https://lore.kernel.org/linux-btrfs/20260125125129.2245240-1-clm@meta.com/
Fixes: 979e1dc3d69e ("btrfs: handle deletions from remapped block group")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix chunk map leak in btrfs_map_block() after btrfs_translate_remap()
Mark Harmstone [Fri, 20 Feb 2026 12:52:56 +0000 (12:52 +0000)] 
btrfs: fix chunk map leak in btrfs_map_block() after btrfs_translate_remap()

If the call to btrfs_translate_remap() in btrfs_map_block() returns an
error code, we were leaking the chunk map. Fix it by jumping to out
rather than returning directly.

Reported-by: Chris Mason <clm@fb.com>
Link: https://lore.kernel.org/linux-btrfs/20260125125830.2352988-1-clm@meta.com/
Fixes: 18ba64992871 ("btrfs: redirect I/O for remapped block groups")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix chunk map leak in btrfs_map_block() after btrfs_chunk_map_num_copies()
Mark Harmstone [Fri, 20 Feb 2026 12:53:17 +0000 (12:53 +0000)] 
btrfs: fix chunk map leak in btrfs_map_block() after btrfs_chunk_map_num_copies()

Fix a chunk map leak in btrfs_map_block(): if we return early with -EINVAL,
we're not freeing the chunk map that we've just looked up.

Fixes: 0ae653fbec2b ("btrfs: reduce chunk_map lookups in btrfs_map_block()")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix compat mask in error messages in btrfs_check_features()
Mark Harmstone [Tue, 17 Feb 2026 17:46:41 +0000 (17:46 +0000)] 
btrfs: fix compat mask in error messages in btrfs_check_features()

Commit d7f67ac9a928 ("btrfs: relax block-group-tree feature dependency
checks") introduced a regression when it comes to handling unsupported
incompat or compat_ro flags. Beforehand we only printed the flags that
we didn't recognize, afterwards we printed them all, which is less
useful. Fix the error handling so it behaves like it used to.

Fixes: d7f67ac9a928 ("btrfs: relax block-group-tree feature dependency checks")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: print correct subvol num if active swapfile prevents deletion
Mark Harmstone [Tue, 17 Feb 2026 17:32:39 +0000 (17:32 +0000)] 
btrfs: print correct subvol num if active swapfile prevents deletion

Fix the error message in btrfs_delete_subvolume() if we can't delete a
subvolume because it has an active swapfile: we were printing the number
of the parent rather than the target.

Fixes: 60021bd754c6 ("btrfs: prevent subvol with swapfile from being deleted")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix warning in scrub_verify_one_metadata()
Mark Harmstone [Tue, 17 Feb 2026 17:46:13 +0000 (17:46 +0000)] 
btrfs: fix warning in scrub_verify_one_metadata()

Commit b471965fdb2d ("btrfs: fix replace/scrub failure with
metadata_uuid") fixed the comparison in scrub_verify_one_metadata() to
use metadata_uuid rather than fsid, but left the warning as it was. Fix
it so it matches what we're doing.

Fixes: b471965fdb2d ("btrfs: fix replace/scrub failure with metadata_uuid")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix objectid value in error message in check_extent_data_ref()
Mark Harmstone [Tue, 17 Feb 2026 14:39:46 +0000 (14:39 +0000)] 
btrfs: fix objectid value in error message in check_extent_data_ref()

Fix a copy-paste error in check_extent_data_ref(): we're printing root
as in the message above, we should be printing objectid.

Fixes: f333a3c7e832 ("btrfs: tree-checker: validate dref root and objectid")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix incorrect key offset in error message in check_dev_extent_item()
Mark Harmstone [Tue, 17 Feb 2026 10:21:44 +0000 (10:21 +0000)] 
btrfs: fix incorrect key offset in error message in check_dev_extent_item()

Fix the error message in check_dev_extent_item(), when an overlapping
stripe is encountered. For dev extents, objectid is the disk number and
offset the physical address, so prev_key->objectid should actually be
prev_key->offset.

(I can't take any credit for this one - this was discovered by Chris and
his friend Claude.)

Reported-by: Chris Mason <clm@fb.com>
Fixes: 008e2512dc56 ("btrfs: tree-checker: add dev extent item checks")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix error message order of parameters in btrfs_delete_delayed_dir_index()
Mark Harmstone [Tue, 17 Feb 2026 18:25:42 +0000 (18:25 +0000)] 
btrfs: fix error message order of parameters in btrfs_delete_delayed_dir_index()

Fix the error message in btrfs_delete_delayed_dir_index() if
__btrfs_add_delayed_item() fails: the message says root, inode, index,
error, but we're actually passing index, root, inode, error.

Fixes: adc1ef55dc04 ("btrfs: add details to error messages at btrfs_delete_delayed_dir_index()")
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: don't commit the super block when unmounting a shutdown filesystem
Miquel Sabaté Solà [Mon, 16 Feb 2026 00:22:52 +0000 (01:22 +0100)] 
btrfs: don't commit the super block when unmounting a shutdown filesystem

When unmounting a filesystem we will try, among many other things, to
commit the super block. On a filesystem that was shutdown, though, this
will always fail with -EROFS as writes are forbidden on this context;
and an error will be reported.

Don't commit the super block on this situation, which should be fine as
the filesystem is frozen before shutdown and, therefore, it should be at
a consistent state.

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: free pages on error in btrfs_uring_read_extent()
Miquel Sabaté Solà [Mon, 16 Feb 2026 21:12:15 +0000 (22:12 +0100)] 
btrfs: free pages on error in btrfs_uring_read_extent()

In this function the 'pages' object is never freed in the hopes that it is
picked up by btrfs_uring_read_finished() whenever that executes in the
future. But that's just the happy path. Along the way previous
allocations might have gone wrong, or we might not get -EIOCBQUEUED from
btrfs_encoded_read_regular_fill_pages(). In all these cases, we go to a
cleanup section that frees all memory allocated by this function without
assuming any deferred execution, and this also needs to happen for the
'pages' allocation.

Fixes: 34310c442e17 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)")
Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: fix referenced/exclusive check in squota_check_parent_usage()
Boris Burkov [Wed, 11 Feb 2026 19:01:25 +0000 (11:01 -0800)] 
btrfs: fix referenced/exclusive check in squota_check_parent_usage()

We compared rfer_cmpr against excl_cmpr_sum instead of rfer_cmpr_sum
which is confusing.

I expect that
rfer_cmpr == excl_cmpr in squota, but it is much better to be consistent
in case of any surprises or bugs.

Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/cover.1764796022.git.boris@bur.io/T/#mccb231643ffd290b44a010d4419474d280be5537
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove pointless WARN_ON() in cache_save_setup()
Filipe Manana [Tue, 10 Feb 2026 14:23:29 +0000 (14:23 +0000)] 
btrfs: remove pointless WARN_ON() in cache_save_setup()

This WARN_ON(ret) is never executed since the previous if statement makes
us jump into the 'out_put' label when ret is not zero. The existing
transaction abort inside the if statement also gives us a stack trace,
so we don't need to move the WARN_ON(ret) into the if statement either.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: convert log messages to error level in btrfs_replay_log()
Filipe Manana [Mon, 9 Feb 2026 09:49:49 +0000 (09:49 +0000)] 
btrfs: convert log messages to error level in btrfs_replay_log()

We are logging messages as warnings but they should really have an error
level instead, as if the respective conditions are met the mount will
fail. So convert them to error level and also log the error code returned
by read_tree_block().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove btrfs_handle_fs_error() after failure to recover log trees
Filipe Manana [Mon, 9 Feb 2026 15:47:57 +0000 (15:47 +0000)] 
btrfs: remove btrfs_handle_fs_error() after failure to recover log trees

There is no need to call btrfs_handle_fs_error() (which we are trying to
deprecate) if we fail to recover log trees:

1) Such a failure results in failing the mount immediately;

2) If the recovery started a transaction before failing, it has already
   aborted the transaction down in the call chain.

So remove the btrfs_handle_fs_error() call, replace it with an error
message and assert that the FS is in error state (so that no partial
updates are committed due to a transaction that was not aborted).

Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: remove redundant warning message in btrfs_check_uuid_tree()
Filipe Manana [Mon, 9 Feb 2026 15:37:41 +0000 (15:37 +0000)] 
btrfs: remove redundant warning message in btrfs_check_uuid_tree()

If we fail to start the UUID rescan kthread, btrfs_check_uuid_tree() logs
an error message and returns the error to the single caller, open_ctree().

This however is redundant since the caller already logs an error message,
which is also more informative since it logs the error code. Some remove
the warning message from btrfs_check_uuid_tree() as it doesn't add any
value.

Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: change warning messages to error level in open_ctree()
Filipe Manana [Mon, 9 Feb 2026 15:27:14 +0000 (15:27 +0000)] 
btrfs: change warning messages to error level in open_ctree()

Failure to read the fs root results in a mount error, but we log a warning
message. Same goes for checking the UUID tree, an error results in a mount
failure but we log a warning message. Change the level of the logged
messages from warning to error.

Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: fix a double release on reserved extents in cow_one_range()
Qu Wenruo [Mon, 9 Feb 2026 03:31:45 +0000 (14:01 +1030)] 
btrfs: fix a double release on reserved extents in cow_one_range()

[BUG]
Commit c28214bde6da ("btrfs: refactor the main loop of
cow_file_range()") refactored the handling of COWing one range.

However it changed the error handling of the reserved extent.

The old cleanup looks like this:

out_drop_extent_cache:
btrfs_drop_extent_map_range(inode, start, start + cur_alloc_size - 1, false);
out_reserve:
btrfs_dec_block_group_reservations(fs_info, ins.objectid);
btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, true);
[...]
clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
     EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
page_ops = PAGE_UNLOCK | PAGE_START_WRITEBACK | PAGE_END_WRITEBACK;
/*
 * For the range (2). If we reserved an extent for our delalloc range
 * (or a subrange) and failed to create the respective ordered extent,
 * then it means that when we reserved the extent we decremented the
 * extent's size from the data space_info's bytes_may_use counter and
 * incremented the space_info's bytes_reserved counter by the same
 * amount. We must make sure extent_clear_unlock_delalloc() does not try
 * to decrement again the data space_info's bytes_may_use counter,
 * therefore we do not pass it the flag EXTENT_CLEAR_DATA_RESV.
 */
if (cur_alloc_size) {
        extent_clear_unlock_delalloc(inode, start,
                                     start + cur_alloc_size - 1,
                                     locked_folio, &cached, clear_bits,
                                     page_ops);
        btrfs_qgroup_free_data(inode, NULL, start, cur_alloc_size, NULL);
}

Which only calls EXTENT_CLEAR_META_RESV.
As the reserved extent is properly handled by
btrfs_free_reserved_extent().

However the new cleanup is:

extent_clear_unlock_delalloc(inode, file_offset, cur_end, locked_folio, cached,
     EXTENT_LOCKED | EXTENT_DELALLOC |
     EXTENT_DELALLOC_NEW |
     EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
     PAGE_UNLOCK | PAGE_START_WRITEBACK |
     PAGE_END_WRITEBACK);
btrfs_qgroup_free_data(inode, NULL, file_offset, cur_len, NULL);
btrfs_dec_block_group_reservations(fs_info, ins->objectid);
btrfs_free_reserved_extent(fs_info, ins->objectid, ins->offset, true);

The flag EXTENT_DO_ACCOUNTING implies both EXTENT_CLEAR_META_RESV and
EXTENT_CLEAR_DATA_RESV, which will release the bytes_may_use, which
later btrfs_free_reserved_extent() will do again, causing incorrect
double release (and may underflow bytes_may_use).

[FIX]
Use EXTENT_CLEAR_META_RESV to replace EXTENT_DO_ACCOUNTING, and add back
the comments on why we only use EXTENT_CLEAR_META_RESV.

Fixes: c28214bde6da ("btrfs: refactor the main loop of cow_file_range()")
Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/20260208184920.1102719-1-clm@meta.com/
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: handle discard errors in in btrfs_finish_extent_commit()
Jingkai Tan [Thu, 22 Jan 2026 21:14:10 +0000 (21:14 +0000)] 
btrfs: handle discard errors in in btrfs_finish_extent_commit()

Coverity (ID: 1226842) reported that the return value of
btrfs_discard_extent() is assigned to ret but is immediately
overwritten by unpin_extent_range() without being checked.

Use the same error handling that is done later in the same function.

Signed-off-by: Jingkai Tan <contact@jingk.ai>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not found
Filipe Manana [Wed, 4 Feb 2026 17:15:53 +0000 (17:15 +0000)] 
btrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not found

If btrfs_search_slot_for_read() returns 1, it means we did not find any
key greater than or equals to the key we asked for, meaning we have
reached the end of the tree and therefore the path is not valid. If
this happens we need to break out of the loop and stop, instead of
continuing and accessing an invalid path.

Fixes: 5223cc60b40a ("btrfs: drop the path before adding qgroup items when enabling qgroups")
Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: fix lost error return in btrfs_find_orphan_roots()
Filipe Manana [Sun, 8 Feb 2026 19:48:14 +0000 (19:48 +0000)] 
btrfs: fix lost error return in btrfs_find_orphan_roots()

If the call to btrfs_get_fs_root() returns an error different from -ENOENT
we break out of the loop and then return 0, losing the error. Fix this
by returning the error instead of breaking from the loop.

Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/20260208185321.1128472-1-clm@meta.com/
Fixes: 8670a25ecb2f ("btrfs: use single return variable in btrfs_find_orphan_roots()")
Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: fix lost return value on error in finish_verity()
Filipe Manana [Sun, 8 Feb 2026 18:30:08 +0000 (18:30 +0000)] 
btrfs: fix lost return value on error in finish_verity()

If btrfs_update_inode() or del_orphan() fail, we jump to the 'end_trans'
label and then return 0 instead of the error returned by one of those
calls. Fix this and return the error.

Fixes: 61fb7f04ee06 ("btrfs: remove out label in finish_verity()")
Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-btrfs/20260208161129.3888234-1-clm@meta.com/
Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: change unaligned root messages to error level in btrfs_validate_super()
Filipe Manana [Tue, 3 Feb 2026 15:59:26 +0000 (15:59 +0000)] 
btrfs: change unaligned root messages to error level in btrfs_validate_super()

If the root nodes for the chunk root, tree root or log root are not sector
size aligned, we are logging a warning message but these are in fact
errors that makes the super block validation fail. So change the level of
the messages from warning to error.

Reviewed-by: Qu Wenruo <wqu@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>
3 months agobtrfs: use the correct type to initialize block reserve for delayed refs
Filipe Manana [Tue, 3 Feb 2026 18:03:35 +0000 (18:03 +0000)] 
btrfs: use the correct type to initialize block reserve for delayed refs

When initializing the delayed refs block reserve for a transaction handle
we are passing a type of BTRFS_BLOCK_RSV_DELOPS, which is meant for
delayed items and not for delayed refs. The correct type for delayed refs
is BTRFS_BLOCK_RSV_DELREFS.

On release of any excess space reserved in a local delayed refs reserve,
we also should transfer that excess space to the global block reserve
(it it's full, we return to the space info for general availability).

By initializing a transaction's local delayed refs block reserve with a
type of BTRFS_BLOCK_RSV_DELOPS, we were also causing any excess space
released from the delayed block reserve (fs_info->delayed_block_rsv, used
for delayed inodes and items) to be transferred to the global block
reserve instead of the global delayed refs block reserve. This was an
unintentional change in commit 28270e25c69a ("btrfs: always reserve space
for delayed refs when starting transaction"), but it's not particularly
serious as things tend to cancel out each other most of the time and it's
relatively rare to be anywhere near exhaustion of the global reserve.

Fix this by initializing a transaction's local delayed refs reserve with
a type of BTRFS_BLOCK_RSV_DELREFS and making btrfs_block_rsv_release()
attempt to transfer unused space from such a reserve into the global block
reserve, just as we did before that commit for when the block reserve is
a delayed refs rsv.

Reported-by: Alex Lyakas <alex.lyakas@zadara.com>
Link: https://lore.kernel.org/linux-btrfs/CAOcd+r0FHG5LWzTSu=LknwSoqxfw+C00gFAW7fuX71+Z5AfEew@mail.gmail.com/
Fixes: 28270e25c69a ("btrfs: always reserve space for delayed refs when starting transaction")
Reviewed-by: Alex Lyakas <alex.lyakas@zadara.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()
Qu Wenruo [Tue, 27 Jan 2026 05:16:55 +0000 (15:46 +1030)] 
btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()

[BUG]
There is a bug report that when btrfs hits ENOSPC error in a critical
path, btrfs flips RO (this part is expected, although the ENOSPC bug
still needs to be addressed).

The problem is after the RO flip, if there is a read repair pending, we
can hit the ASSERT() inside btrfs_repair_io_failure() like the following:

  BTRFS info (device vdc): relocating block group 30408704 flags metadata|raid1
  ------------[ cut here ]------------
  BTRFS: Transaction aborted (error -28)
  WARNING: fs/btrfs/extent-tree.c:3235 at __btrfs_free_extent.isra.0+0x453/0xfd0, CPU#1: btrfs/383844
  Modules linked in: kvm_intel kvm irqbypass
  [...]
  ---[ end trace 0000000000000000 ]---
  BTRFS info (device vdc state EA): 2 enospc errors during balance
  BTRFS info (device vdc state EA): balance: ended with status: -30
  BTRFS error (device vdc state EA): parent transid verify failed on logical 30556160 mirror 2 wanted 8 found 6
  BTRFS error (device vdc state EA): bdev /dev/nvme0n1 errs: wr 0, rd 0, flush 0, corrupt 10, gen 0
  [...]
  assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938
  ------------[ cut here ]------------
  assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938
  kernel BUG at fs/btrfs/bio.c:938!
  Oops: invalid opcode: 0000 [#1] SMP NOPTI
  CPU: 0 UID: 0 PID: 868 Comm: kworker/u8:13 Tainted: G        W        N  6.19.0-rc6+ #4788 PREEMPT(full)
  Tainted: [W]=WARN, [N]=TEST
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
  Workqueue: btrfs-endio simple_end_io_work
  RIP: 0010:btrfs_repair_io_failure.cold+0xb2/0x120
  RSP: 0000:ffffc90001d2bcf0 EFLAGS: 00010246
  RAX: 0000000000000051 RBX: 0000000000001000 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffffffff8305cf42 RDI: 00000000ffffffff
  RBP: 0000000000000002 R08: 00000000fffeffff R09: ffffffff837fa988
  R10: ffffffff8327a9e0 R11: 6f69747265737361 R12: ffff88813018d310
  R13: ffff888168b8a000 R14: ffffc90001d2bd90 R15: ffff88810a169000
  FS:  0000000000000000(0000) GS:ffff8885e752c000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  ------------[ cut here ]------------

[CAUSE]
The cause of -ENOSPC error during the test case btrfs/124 is still
unknown, although it's known that we still have cases where metadata can
be over-committed but can not be fulfilled correctly, thus if we hit
such ENOSPC error inside a critical path, we have no choice but abort
the current transaction.

This will mark the fs read-only.

The problem is inside the btrfs_repair_io_failure() path that we require
the fs not to be mount read-only. This is normally fine, but if we are
doing a read-repair meanwhile the fs flips RO due to a critical error,
we can enter btrfs_repair_io_failure() with super block set to
read-only, thus triggering the above crash.

[FIX]
Just replace the ASSERT() with a proper return if the fs is already
read-only.

Reported-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-btrfs/20260126045555.GB31641@lst.de/
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: reset block group size class when it becomes empty
Jiasheng Jiang [Wed, 14 Jan 2026 01:13:38 +0000 (01:13 +0000)] 
btrfs: reset block group size class when it becomes empty

Block group size classes are managed consistently everywhere.
Currently, btrfs_use_block_group_size_class() sets a block group's size
class to specialize it for a specific allocation size. However, this
size class remains "stale" even if the block group becomes completely
empty (both used and reserved bytes reach zero).

This happens in two scenarios:

1. When space reservations are freed (e.g., due to errors or transaction
   aborts) via btrfs_free_reserved_bytes().
2. When the last extent in a block group is freed via
   btrfs_update_block_group().

While size classes are advisory, a stale size class can cause
find_free_extent to unnecessarily skip candidate block groups during
initial search loops. This undermines the purpose of size classes to
reduce fragmentation by keeping block groups restricted to a specific
size class when they could be reused for any size.

Fix this by resetting the size class to BTRFS_BG_SZ_NONE whenever a
block group's used and reserved counts both reach zero. This ensures
that empty block groups are fully available for any allocation size in
the next cycle.

Fixes: 52bb7a2166af ("btrfs: introduce size class to block group allocator")
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: replace BUG() with error handling in __btrfs_balance()
Adarsh Das [Tue, 3 Feb 2026 17:23:57 +0000 (22:53 +0530)] 
btrfs: replace BUG() with error handling in __btrfs_balance()

We search with offset (u64)-1 which should never match exactly.
Previously this was handled with BUG(). Now logs an error
and return -EUCLEAN.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Adarsh Das <adarshdas950@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: handle unexpected exact match in btrfs_set_inode_index_count()
Adarsh Das [Tue, 3 Feb 2026 17:23:56 +0000 (22:53 +0530)] 
btrfs: handle unexpected exact match in btrfs_set_inode_index_count()

We search with offset (u64)-1 which should never match exactly.
Previously the code silently returned success without setting the index
count. Now logs an error and return -EUCLEAN instead.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Adarsh Das <adarshdas950@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>,
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: get rid of compressed_bio::compressed_folios[]
Qu Wenruo [Thu, 29 Jan 2026 03:23:46 +0000 (13:53 +1030)] 
btrfs: get rid of compressed_bio::compressed_folios[]

Now there is no one utilizing that member, we can safely remove it along
with compressed_bio::nr_folios member. The size is reduced from 352 to
336 bytes on x86_64.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: get rid of compressed_folios[] usage for encoded writes
Qu Wenruo [Thu, 29 Jan 2026 03:23:45 +0000 (13:53 +1030)] 
btrfs: get rid of compressed_folios[] usage for encoded writes

Currently only encoded writes utilized btrfs_submit_compressed_write(),
which utilized compressed_bio::compressed_folios[] array.

Change the only call site to call the new helper,
btrfs_alloc_compressed_write(), to allocate a compressed bio, then queue
needed folios into that bio, and finally call
btrfs_submit_compressed_write() to submit the compressed bio.

This change has one hidden benefit, previously we used
btrfs_alloc_folio_array() for the folios of
btrfs_submit_compressed_read(), which doesn't utilize the compression
page pool for bs == ps cases.

Now we call btrfs_alloc_compr_folio() which will benefit from the page pool.

The other obvious benefit is that we no longer need to allocate an array
to hold all those folios, thus one less error path.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: get rid of compressed_folios[] usage for compressed read
Qu Wenruo [Thu, 29 Jan 2026 03:23:44 +0000 (13:53 +1030)] 
btrfs: get rid of compressed_folios[] usage for compressed read

Currently btrfs_submit_compressed_read() still uses
compressed_bio::compressed_folios[] array.

Change it to allocate each folio and queue them into the compressed bio
so that we do not need to allocate that array.

Considering how small each compressed read bio is (less than 128KiB), we
do not benefit that much from btrfs_alloc_folio_array() anyway,
while we may benefit more from btrfs_alloc_compr_folio() by using
the global folio pool.

So changing from btrfs_alloc_folio_array() to btrfs_alloc_compr_folio()
in a loop should still be fine.

This removes one error path, and paves the way to completely remove
compressed_folios[] array.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove the old btrfs_compress_folios() infrastructure
Qu Wenruo [Thu, 29 Jan 2026 03:23:43 +0000 (13:53 +1030)] 
btrfs: remove the old btrfs_compress_folios() infrastructure

Since it's been replaced by btrfs_compress_bio(), remove all involved
functions.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: switch to btrfs_compress_bio() interface for compressed writes
Qu Wenruo [Thu, 29 Jan 2026 03:23:42 +0000 (13:53 +1030)] 
btrfs: switch to btrfs_compress_bio() interface for compressed writes

This switch has the following benefits:

- A single structure to handle all compression

  No more extra members like compressed_folios[] nor compress_type, all
  those members.

  This means the structure of async_extent is much smaller.

- Simpler error handling

  A single cleanup_compressed_bio() will handle everything, no extra
  compressed_folios[] array to bother.

Some extra notes:

- Compressed folios releasing

  Now we go bio_for_each_folio_all() loop to release the folios of the
  bio. This will work for both the old compressed_folios[] array and the
  new pure bio method.

  For old compressed_folios[], all folios of that array is queued into
  the bio, thus releasing the folios from the bio is the same as
  releasing each folio of that array. We just need to be sure no double
  releasing from the array and bio.

  For the new pure bio method, that array is NULL, just usual folio
  releasing of the bio.

  The only extra note is for end_bbio_compressed_read(), as the folios
  are allocated using btrfs_alloc_folio_array(), thus the folios should
  only be released by regular folio_put(), not btrfs_free_compr_folio().

- Rounding up the bio to block size

  We cannot simply increase bi_size, as that will not increase the
  length of the last bvec.

  Thus we have to properly add the last part into the bio.
  This will be done by the helper, round_up_last_block().

  The reason we do not round those bios up at compression time is to get
  the unaligned compressed size, so that they can be utilized for
  inline extents.
  If we round the bios up at *_compress_bio(), then every compressed bio
  will be larger than or equal to one fs block, resulting no inline
  compressed extent.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: introduce btrfs_compress_bio() helper
Qu Wenruo [Thu, 29 Jan 2026 03:23:41 +0000 (13:53 +1030)] 
btrfs: introduce btrfs_compress_bio() helper

The helper will allocate a new compressed_bio, do the compression, and
return it to the caller.

This greatly simplifies the compression path, as we no longer need to
allocate a folio array thus no extra error path, furthermore the
compressed bio structure can be utilized for submission with very minor
modifications (like rounding up the bi_size and populate the bi_sector).

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zlib: introduce zlib_compress_bio() helper
Qu Wenruo [Thu, 29 Jan 2026 03:23:40 +0000 (13:53 +1030)] 
btrfs: zlib: introduce zlib_compress_bio() helper

The new helper has the following enhancements against the existing
zlib_compress_folios()

- Much smaller parameter list

  No more shared IN/OUT members, no need to pre-allocate a
  compressed_folios[] array.

  Just a workspace and compressed_bio pointer, everything we need can be
  extracted from that @cb pointer.

- Ready-to-be-submitted compressed bio

  Although the caller still needs to do some common works like
  rounding up and zeroing the tailing part of the last fs block.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zstd: introduce zstd_compress_bio() helper
Qu Wenruo [Thu, 29 Jan 2026 03:23:39 +0000 (13:53 +1030)] 
btrfs: zstd: introduce zstd_compress_bio() helper

The new helper has the following enhancements against the existing
zstd_compress_folios()

- Much smaller parameter list

  No more shared IN/OUT members, no need to pre-allocate a
  compressed_folios[] array.

  Just a workspace and compressed_bio pointer, everything we need can be
  extracted from that @cb pointer.

- Ready-to-be-submitted compressed bio

  Although the caller still needs to do some common works like
  rounding up and zeroing the tailing part of the last fs block.

Overall the workflow is the same as zstd_compress_folios(), but with
some minor changes:

- @start/@len is now constant
  For the current input file offset, use @start + @tot_in instead.

  The original change of @start and @len makes it pretty hard to know
  what value we're really comparing to.

- No more @cur_len
  It's only utilized when switching input buffer.
  Directly use btrfs_calc_input_length() instead.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: lzo: introduce lzo_compress_bio() helper
Qu Wenruo [Thu, 29 Jan 2026 03:23:38 +0000 (13:53 +1030)] 
btrfs: lzo: introduce lzo_compress_bio() helper

The new helper has the following enhancements against the existing
lzo_compress_folios()

- Much smaller parameter list

  No more shared IN/OUT members, no need to pre-allocate a
  compressed_folios[] array.

  Just a workspace list header and a compressed_bio pointer.

  Everything else can be fetched from that @cb pointer.

- Read-to-be-submitted compressed bio

  Although the caller still needs to do some common works like
  rounding up and zeroing the tailing part of the last fs block.

Some workloads are specific to lZO that is not needed with other
multi-run compression interfaces:

- Need to write a LZO header or segment header

  Use the new write_and_queue_folio() helper to do the bio_add_folio()
  call and folio switching.

- Need to update the LZO header after compression is done

  Use bio_first_folio_all() to grab the first folio and update the header.

- Extra corner case of error handling

  This can happen when we have queued part of a folio and hit an error.
  In that case those folios will be released by the bio.
  Thus we can only release the folio that has no queued part.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zoned: factor out the zone loading part into a testable function
Naohiro Aota [Mon, 26 Jan 2026 05:49:52 +0000 (14:49 +0900)] 
btrfs: zoned: factor out the zone loading part into a testable function

Separate btrfs_load_block_group_* calling path into a function, so that it
can be an entry point of unit test.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: add cleanup function for btrfs_free_chunk_map
Naohiro Aota [Mon, 26 Jan 2026 05:49:51 +0000 (14:49 +0900)] 
btrfs: add cleanup function for btrfs_free_chunk_map

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: tests: add cleanup functions for test specific functions
Naohiro Aota [Mon, 26 Jan 2026 05:49:50 +0000 (14:49 +0900)] 
btrfs: tests: add cleanup functions for test specific functions

Add auto-cleanup helper functions for btrfs_free_dummy_fs_info and
btrfs_free_dummy_block_group.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: raid56: fix memory leak of btrfs_raid_bio::stripe_uptodate_bitmap
Filipe Manana [Fri, 30 Jan 2026 17:06:45 +0000 (17:06 +0000)] 
btrfs: raid56: fix memory leak of btrfs_raid_bio::stripe_uptodate_bitmap

We allocate the bitmap but we never free it in free_raid_bio_pointers().
Fix this by adding a bitmap_free() call against the stripe_uptodate_bitmap
of a raid bio.

Fixes: 1810350b04ef ("btrfs: raid56: move sector_ptr::uptodate into a dedicated bitmap")
Reported-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-btrfs/20260126045315.GA31641@lst.de/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: tests: add unit tests for pending extent walking functions
Boris Burkov [Fri, 30 Jan 2026 00:11:22 +0000 (16:11 -0800)] 
btrfs: tests: add unit tests for pending extent walking functions

I ran into another sort of trivial bug in v1 of the patch and concluded
that these functions really ought to be unit tested.

These two functions form the core of searching the chunk allocation
pending extent bitmap and have relatively easily definable semantics, so
unit testing them can help ensure the correctness of chunk allocation.

I also made a minor unrelated fix in volumes.h to properly forward
declare btrfs_space_info. Because of the order of the includes in the
new test, this was actually hitting a latent build warning.

Note:
This is an early example for me of a commit authored in part by an AI
agent, so I wanted to more clear about what I did. I defined a
trivial test and explained the set of tests I wanted to the agent and it
produced the large set of test cases seen here. I then checked each test
case to make sure it matched the description and simplified the
constants and numbers until they looked reasonable to me. I then checked
the looping logic to make sure it made sense to the original spirit of
the trivial test. Finally, carefully combed over all the lines it wrote
to loop over the tests it generated to make sure they followed our code
style guide.

Assisted-by: Claude:claude-opus-4-5
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation
Boris Burkov [Fri, 30 Jan 2026 00:11:21 +0000 (16:11 -0800)] 
btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation

I have been observing a number of systems aborting at
insert_dev_extents() in btrfs_create_pending_block_groups(). The
following is a sample stack trace of such an abort coming from forced
chunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this
can theoretically happen to any DUP chunk allocation.

  [81.801] ------------[ cut here ]------------
  [81.801] BTRFS: Transaction aborted (error -17)
  [81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319
  [81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk
  [81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE
  [81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014
  [81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs]
  [81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282
  [81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000
  [81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0
  [81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007
  [81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000
  [81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000
  [81.809] FS:  00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000
  [81.809] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0
  [81.810] Call Trace:
  [81.810]  <TASK>
  [81.810]  __btrfs_end_transaction+0x3e/0x2b0 [btrfs]
  [81.811]  btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs]
  [81.811]  kernfs_fop_write_iter+0x15f/0x240
  [81.812]  vfs_write+0x264/0x500
  [81.812]  ksys_write+0x6c/0xe0
  [81.812]  do_syscall_64+0x66/0x770
  [81.812]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [81.813] RIP: 0033:0x7fec6be66197
  [81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
  [81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197
  [81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001
  [81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000
  [81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
  [81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0
  [81.817]  </TASK>
  [81.817] irq event stamp: 20039
  [81.818] hardirqs last  enabled at (20047): [<ffffffff99a68302>] __up_console_sem+0x52/0x60
  [81.818] hardirqs last disabled at (20056): [<ffffffff99a682e7>] __up_console_sem+0x37/0x60
  [81.819] softirqs last  enabled at (19470): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0
  [81.819] softirqs last disabled at (19463): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0
  [81.820] ---[ end trace 0000000000000000 ]---
  [81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists

Inspecting these aborts with drgn, I observed a pattern of overlapping
chunk_maps. Note how stripe 1 of the first chunk overlaps in physical
address with stripe 0 of the second chunk.

Physical Start     Physical End       Length       Logical            Type                 Stripe
----------------------------------------------------------------------------------------------------
0x0000000102500000 0x0000000142500000 1.0G         0x0000000641d00000 META|DUP             0/2
0x0000000142500000 0x0000000182500000 1.0G         0x0000000641d00000 META|DUP             1/2
0x0000000142500000 0x0000000182500000 1.0G         0x0000000601d00000 META|DUP             0/2
0x0000000182500000 0x00000001c2500000 1.0G         0x0000000601d00000 META|DUP             1/2

Now how could this possibly happen? All chunk allocation is protected by
the chunk_mutex so racing allocations should see a consistent view of
the CHUNK_ALLOCATED bit in the chunk allocation extent-io-tree
(device->alloc_state as set by chunk_map_device_set_bits()) The tree
itself is protected by a spin lock, and clearing/setting the bits is
always protected by fs_info->mapping_tree_lock, so no race is apparent.

It turns out that there is a subtle bug in the logic regarding chunk
allocations that have happened in the current transaction, known as
"pending extents". The chunk allocation as defined in
find_free_dev_extent() is a loop which searches the commit root of the
dev_root and looks for gaps between DEV_EXTENT items. For those gaps, it
then checks alloc_state bitmap for any pending extents and adjusts the
hole that it finds accordingly. However, the logic in that adjustment
assumes that the first pending extent is the only one in that range.

e.g., given a layout with two non-consecutive pending extents in a hole
passed to dev_extent_hole_check() via *hole_start and *hole_size:

  |----pending A----|    real hole     |----pending B----|
           |           candidate hole        |
      *hole_start                         *hole_start + *hole_size

the code incorrectly returns a "hole" from the end of pending extent A
until the passed in hole end, failing to account for pending B.

However, it is not entirely obvious that it is actually possible to
produce such a layout. I was able to reproduce it, but with some
contortions: I continued to use the force chunk allocation sysfs file
and I introduced a long delay (10 seconds) into the start of the cleaner
thread. I also prevented the unused bgs cleaning logic from ever
deleting metadata bgs. These help make it easier to deterministically
produce the condition but shouldn't really matter if you imagine the
conditions happening by race/luck. Allocations/frees can happen
concurrently with the cleaner thread preparing to process an unused
extent and both create some used chunks with an unused chunk
interleaved, all during one transaction. Then btrfs_delete_unused_bgs()
sees the unused one and clears it, leaving a range with several pending
chunk allocations and a gap in the middle.

The basic idea is that the unused_bgs cleanup work happens on a worker
so if we allocate 3 block groups in one transaction, then the cleaner
work kicked off by the previous transaction comes through and deletes
the middle one of the 3, then the commit root shows no dev extents and
we have the bad pattern in the extent-io-tree. One final consideration
is that the code happens to loop to the next hole if there are no more
extents at all, so we need one more dev extent way past the area we are
working in. Something like the following demonstrates the technique:

  # push the BG frontier out to 20G
  fallocate -l 20G $mnt/foo
  # allocate one more that will prevent the "no more dev extents" luck
  fallocate -l 1G $mnt/sticky
  # sync
  sync
  # clear out the allocation area
  rm $mnt/foo
  sync
  _cleaner
  # let everything quiesce
  sleep 20
  sync

  # dev tree should have one bg 20G out and the rest at the beginning..
  # sort of like an empty FS but with a random sticky chunk.

  # kick off the cleaner in the background, remember it will sleep 10s
  # before doing interesting work
  _cleaner &

  sleep 3

  # create 3 trivial block groups, all empty, all immediately marked as unused.
  echo 1 > "$(_btrfs_sysfs_space_info $dev metadata)/force_chunk_alloc"
  echo 1 > "$(_btrfs_sysfs_space_info $dev data)/force_chunk_alloc"
  echo 1 > "$(_btrfs_sysfs_space_info $dev metadata)/force_chunk_alloc"

  # let the cleaner thread definitely finish, it will remove the data bg
  sleep 10

  # this allocation sees the non-consecutive pending metadata chunks with
  # data chunk gap of 1G and allocates a 2G extent in that hole. ENOSPC!
  echo 1 > "$(_btrfs_sysfs_space_info $dev metadata)/force_chunk_alloc"

As for the fix, it is not that obvious. I could not see a trivial way to
do it even by adding backup loops into find_free_dev_extent(), so I
opted to change the semantics of dev_extent_hole_check() to not stop
looping until it finds a sufficiently big hole. For clarity, this also
required changing the helper function contains_pending_extent() into two
new helpers which find the first pending extent and the first suitable
hole in a range.

I attempted to clean up the documentation and range calculations to be
as consistent and clear as possible for the future.

I also looked at the zoned case and concluded that the loop there is
different and not to be unified with this one. As far as I can tell, the
zoned check will only further constrain the hole so looping back to find
more holes is acceptable. Though given that zoned really only appends, I
find it highly unlikely that it is susceptible to this bug.

Fixes: 1b9845081633 ("Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole")
Reported-by: Dimitrios Apostolou <jimis@gmx.net>
Closes: https://lore.kernel.org/linux-btrfs/q7760374-q1p4-029o-5149-26p28421s468@tzk.arg/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix transaction commit blocking during trim of unallocated space
jinbaohong [Wed, 28 Jan 2026 07:06:41 +0000 (07:06 +0000)] 
btrfs: fix transaction commit blocking during trim of unallocated space

When trimming unallocated space, btrfs_trim_fs() holds the device_list_mutex
for the entire duration while iterating through all devices. On large
filesystems with significant unallocated space, this operation can take
minutes to hours on large storage systems.

This causes a problem because btrfs_run_dev_stats(), which is called
during transaction commit, also requires device_list_mutex:

  btrfs_trim_fs()
    mutex_lock(&fs_devices->device_list_mutex)
    list_for_each_entry(device, ...)
      btrfs_trim_free_extents(device)
    mutex_unlock(&fs_devices->device_list_mutex)

  commit_transaction()
    btrfs_run_dev_stats()
      mutex_lock(&fs_devices->device_list_mutex)  // blocked!
      ...

While trim is running, all transaction commits are blocked waiting for
the mutex.

Fix this by refactoring btrfs_trim_free_extents() to process devices in
bounded chunks (up to 2GB per iteration) and release device_list_mutex
between chunks.

Signed-off-by: robbieko <robbieko@synology.com>
Signed-off-by: jinbaohong <jinbaohong@synology.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: handle user interrupt properly in btrfs_trim_fs()
jinbaohong [Wed, 28 Jan 2026 07:06:40 +0000 (07:06 +0000)] 
btrfs: handle user interrupt properly in btrfs_trim_fs()

When a fatal signal is pending or the process is freezing,
btrfs_trim_block_group() and btrfs_trim_free_extents() return -ERESTARTSYS.
Currently this is treated as a regular error: the loops continue to the
next iteration and count it as a block group or device failure.

Instead, break out of the loops immediately and return -ERESTARTSYS to
userspace without counting it as a failure. Also skip the device loop
entirely if the block group loop was interrupted.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: jinbaohong <jinbaohong@synology.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: preserve first error in btrfs_trim_fs()
jinbaohong [Wed, 28 Jan 2026 07:06:39 +0000 (07:06 +0000)] 
btrfs: preserve first error in btrfs_trim_fs()

When multiple block groups or devices fail during trim, preserve the
first error encountered rather than the last one. The first error is
typically more useful for debugging as it represents the original
failure, while subsequent errors may be cascading effects.

Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: jinbaohong <jinbaohong@synology.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: continue trimming remaining devices on failure
jinbaohong [Wed, 28 Jan 2026 07:06:38 +0000 (07:06 +0000)] 
btrfs: continue trimming remaining devices on failure

Commit 93bba24d4b5a ("btrfs: Enhance btrfs_trim_fs function to handle
error better") intended to make device trimming continue even if one
device fails, tracking failures and reporting them at the end. However,
it used 'break' instead of 'continue', causing the loop to exit on the
first device failure.

Fix this by replacing 'break' with 'continue'.

Fixes: 93bba24d4b5a ("btrfs: Enhance btrfs_trim_fs function to handle error better")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: jinbaohong <jinbaohong@synology.com>
Reviewed-by: Filipe Manana <fdmanana@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>
3 months agobtrfs: do not BUG_ON() in btrfs_remove_block_group()
Filipe Manana [Fri, 23 Jan 2026 10:05:12 +0000 (10:05 +0000)] 
btrfs: do not BUG_ON() in btrfs_remove_block_group()

There's no need to BUG_ON(), we can just abort the transaction and return
an error.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: abort transaction on error in btrfs_remove_block_group()
Filipe Manana [Fri, 23 Jan 2026 09:49:57 +0000 (09:49 +0000)] 
btrfs: abort transaction on error in btrfs_remove_block_group()

When btrfs_remove_block_group() fails we abort the transaction in its
single caller (btrfs_remove_chunk()). This makes it harder to find out
where exactly the failure happened, as several steps inside
btrfs_remove_block_group() can fail.

So make btrfs_remove_block_group() abort the transaction whenever an
error happens, instead of aborting in its caller.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix block_group_tree dirty_list corruption
Boris Burkov [Tue, 23 Dec 2025 00:15:44 +0000 (16:15 -0800)] 
btrfs: fix block_group_tree dirty_list corruption

When the incompat flag EXTENT_TREE_V2 is set, we unconditionally add the
block group tree to the switch_commits list before calling
switch_commit_roots, as we do for the tree root and the chunk root.
However, the block group tree uses normal root dirty tracking and in any
transaction that does an allocation and dirties a block group, the block
group root will already be linked to a list by the dirty_list field and
this use of list_add_tail() is invalid and corrupts the prev/next
members of block_group_root->dirty_list.

This is apparent on a subsequent list_del on the prev if we enable
CONFIG_DEBUG_LIST:

  [32.1571] ------------[ cut here ]------------
  [32.1572] list_del corruption. next->prev should beffff958890202538, but was ffff9588992bd538. (next=ffff958890201538)
  [32.1575] WARNING: lib/list_debug.c:65 at 0x0, CPU#3: sync/607
  [32.1583] CPU: 3 UID: 0 PID: 607 Comm: sync Not tainted 6.18.0 #24PREEMPT(none)
  [32.1585] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS1.17.0-4.fc41 04/01/2014
  [32.1587] RIP: 0010:__list_del_entry_valid_or_report+0x108/0x120
  [32.1593] RSP: 0018:ffffaa288287fdd0 EFLAGS: 00010202
  [32.1594] RAX: 0000000000000001 RBX: ffff95889326e800 RCX:ffff958890201538
  [32.1596] RDX: ffff9588992bd538 RSI: ffff958890202538 RDI:ffffffff82a41e00
  [32.1597] RBP: ffff958890202538 R08: ffffffff828fc1e8 R09:00000000ffffefff
  [32.1599] R10: ffffffff8288c200 R11: ffffffff828e4200 R12:ffff958890201538
  [32.1601] R13: ffff95889326e958 R14: ffff958895c24000 R15:ffff958890202538
  [32.1603] FS:  00007f0c28eb5740(0000) GS:ffff958af2bd2000(0000)knlGS:0000000000000000
  [32.1605] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [32.1607] CR2: 00007f0c28e8a3cc CR3: 0000000109942005 CR4:0000000000370ef0
  [32.1609] Call Trace:
  [32.1610]  <TASK>
  [32.1611]  switch_commit_roots+0x82/0x1d0 [btrfs]
  [32.1615]  btrfs_commit_transaction+0x968/0x1550 [btrfs]
  [32.1618]  ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs]
  [32.1621]  __iterate_supers+0xe8/0x190
  [32.1622]  ? __pfx_sync_fs_one_sb+0x10/0x10
  [32.1623]  ksys_sync+0x63/0xb0
  [32.1624]  __do_sys_sync+0xe/0x20
  [32.1625]  do_syscall_64+0x73/0x450
  [32.1626]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [32.1627] RIP: 0033:0x7f0c28d05d2b
  [32.1632] RSP: 002b:00007ffc9d988048 EFLAGS: 00000246 ORIG_RAX:00000000000000a2
  [32.1634] RAX: ffffffffffffffda RBX: 00007ffc9d988228 RCX:00007f0c28d05d2b
  [32.1636] RDX: 00007f0c28e02301 RSI: 00007ffc9d989b21 RDI:00007f0c28dba90d
  [32.1637] RBP: 0000000000000001 R08: 0000000000000001 R09:0000000000000000
  [32.1639] R10: 0000000000000000 R11: 0000000000000246 R12:000055b96572cb80
  [32.1641] R13: 000055b96572b19f R14: 00007f0c28dfa434 R15:000055b96572b034
  [32.1643]  </TASK>
  [32.1644] irq event stamp: 0
  [32.1644] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
  [32.1646] hardirqs last disabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260
  [32.1648] softirqs last  enabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260
  [32.1650] softirqs last disabled at (0): [<0000000000000000>] 0x0
  [32.1652] ---[ end trace 0000000000000000 ]---

Furthermore, this list corruption eventually (when we happen to add a
new block group) results in getting the switch_commits and
dirty_cowonly_roots lists mixed up and attempting to call update_root
on the tree root which can't be found in the tree root, resulting in a
transaction abort:

  [87.8269] BTRFS critical (device nvme1n1): unable to find root key (1 0 0) in tree 1
  [87.8272] ------------[ cut here ]------------
  [87.8274] BTRFS: Transaction aborted (error -117)
  [87.8275] WARNING: fs/btrfs/root-tree.c:153 at 0x0, CPU#4: sync/703
  [87.8285] CPU: 4 UID: 0 PID: 703 Comm: sync Not tainted 6.18.0 #25 PREEMPT(none)
  [87.8287] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-4.fc41 04/01/2014
  [87.8289] RIP: 0010:btrfs_update_root+0x296/0x790 [btrfs]
  [87.8295] RSP: 0018:ffffa58d035dfd60 EFLAGS: 00010282
  [87.8297] RAX: ffff9a59126ddb68 RBX: ffff9a59126dc000 RCX: 0000000000000000
  [87.8299] RDX: 0000000000000000 RSI: 00000000ffffff8b RDI: ffffffffc0b28270
  [87.8301] RBP: ffff9a5904aec000 R08: 0000000000000000 R09: 00000000ffffefff
  [87.8303] R10: ffffffff9ac8c200 R11: ffffffff9ace4200 R12: 0000000000000001
  [87.8305] R13: ffff9a59041740e8 R14: ffff9a5904aec1f7 R15: ffff9a590fdefaf0
  [87.8307] FS:  00007f54cde6b740(0000) GS:ffff9a5b5a81c000(0000) knlGS:0000000000000000
  [87.8309] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [87.8310] CR2: 00007f54cde403cc CR3: 0000000112902004 CR4: 0000000000370ef0
  [87.8312] Call Trace:
  [87.8313]  <TASK>
  [87.8314]  ? _raw_spin_unlock+0x23/0x40
  [87.8315]  commit_cowonly_roots+0x1ad/0x250 [btrfs]
  [87.8317]  ? btrfs_commit_transaction+0x79b/0x1560 [btrfs]
  [87.8320]  btrfs_commit_transaction+0x8aa/0x1560 [btrfs]
  [87.8322]  ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs]
  [87.8325]  __iterate_supers+0xf1/0x170
  [87.8326]  ? __pfx_sync_fs_one_sb+0x10/0x10
  [87.8327]  ksys_sync+0x63/0xb0
  [87.8328]  __do_sys_sync+0xe/0x20
  [87.8329]  do_syscall_64+0x73/0x450
  [87.8330]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [87.8331] RIP: 0033:0x7f54cdd05d2b
  [87.8336] RSP: 002b:00007fff1b58ff78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
  [87.8338] RAX: ffffffffffffffda RBX: 00007fff1b590158 RCX: 00007f54cdd05d2b
  [87.8340] RDX: 00007f54cde02301 RSI: 00007fff1b592b66 RDI: 00007f54cddba90d
  [87.8342] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
  [87.8344] R10: 0000000000000000 R11: 0000000000000246 R12: 000055e07ca96b80
  [87.8346] R13: 000055e07ca9519f R14: 00007f54cddfa434 R15: 000055e07ca95034
  [87.8348]  </TASK>
  [87.8348] irq event stamp: 0
  [87.8349] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
  [87.8351] hardirqs last disabled at (0): [<ffffffff99698797>] copy_process+0xb37/0x21e0
  [87.8353] softirqs last  enabled at (0): [<ffffffff99698797>] copy_process+0xb37/0x21e0
  [87.8355] softirqs last disabled at (0): [<0000000000000000>] 0x0
  [87.8357] ---[ end trace 0000000000000000 ]---
  [87.8358] BTRFS: error (device nvme1n1 state A) in btrfs_update_root:153: errno=-117 Filesystem corrupted
  [87.8360] BTRFS info (device nvme1n1 state EA): forced readonly
  [87.8362] BTRFS warning (device nvme1n1 state EA): Skipping commit of aborted transaction.
  [87.8364] BTRFS: error (device nvme1n1 state EA) in cleanup_transaction:2037: errno=-117 Filesystem corrupted

Since the block group tree was pulled out of the extent tree and uses
normal root dirty tracking, remove the offending extra list_add. This
fixes the list corruption and the resulting fs corruption.

Fixes: 14033b08a029 ("btrfs: don't save block group root into super block")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: fix copying the flags of btrfs_bio after split
Johannes Thumshirn [Mon, 26 Jan 2026 08:05:24 +0000 (09:05 +0100)] 
btrfs: fix copying the flags of btrfs_bio after split

When a btrfs_bio gets split, only 'bbio->csum_search_commit_root' gets
copied to the new btrfs_bio, all the other flags don't.

When a bio is split in btrfs_submit_chunk(), btrfs_split_bio() creates
the new split bio via btrfs_bio_init() which zeroes the struct with
memset. Looking at btrfs_split_bio(), it copies csum_search_commit_root
from the original but does not copy can_use_append.

After the split, the code does:

    bbio = split;
    bio = &bbio->bio;

This means the split bio (with can_use_append = false) gets submitted,
not the original. In btrfs_submit_dev_bio(), the condition:

    if (btrfs_bio(bio)->can_use_append && btrfs_dev_is_sequential(...))

Will be false for the split bio even when writing to a sequential zone.
Does the split bio need to inherit can_use_append from the original? The
old code used a local variable use_append which persisted across the
split.

Copy the rest of the flags as well.

Link: https://lore.kernel.org/linux-btrfs/20260125132120.2525146-1-clm@meta.com/
Reported-by: Chris Mason <clm@meta.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zoned: use local fs_info variable in btrfs_load_block_group_dup()
Johannes Thumshirn [Fri, 23 Jan 2026 08:14:44 +0000 (09:14 +0100)] 
btrfs: zoned: use local fs_info variable in btrfs_load_block_group_dup()

btrfs_load_block_group_dup() has a local pointer to fs_info, yet the
error prints dereference fs_info from the block_group.

Use local fs_info variable to make the code more uniform.

Reviewed-by: Daniel Vacek <neelx@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.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>
3 months agobtrfs: zoned: fixup last alloc pointer after extent removal for RAID0/10
Naohiro Aota [Fri, 23 Jan 2026 12:41:36 +0000 (21:41 +0900)] 
btrfs: zoned: fixup last alloc pointer after extent removal for RAID0/10

When a block group is composed of a sequential write zone and a
conventional zone, we recover the (pseudo) write pointer of the
conventional zone using the end of the last allocated position.

However, if the last extent in a block group is removed, the last extent
position will be smaller than the other real write pointer position.
Then, that will cause an error due to mismatch of the write pointers.

We can fixup this case by moving the alloc_offset to the corresponding
write pointer position.

Fixes: 568220fa9657 ("btrfs: zoned: support RAID0/1/10 on top of raid stripe tree")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zoned: fixup last alloc pointer after extent removal for DUP
Naohiro Aota [Fri, 23 Jan 2026 12:41:35 +0000 (21:41 +0900)] 
btrfs: zoned: fixup last alloc pointer after extent removal for DUP

When a block group is composed of a sequential write zone and a
conventional zone, we recover the (pseudo) write pointer of the
conventional zone using the end of the last allocated position.

However, if the last extent in a block group is removed, the last extent
position will be smaller than the other real write pointer position.
Then, that will cause an error due to mismatch of the write pointers.

We can fixup this case by moving the alloc_offset to the corresponding
write pointer position.

Fixes: c0d90a79e8e6 ("btrfs: zoned: fix alloc_offset calculation for partly conventional block groups")
CC: stable@vger.kernel.org # 6.16+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: zoned: fixup last alloc pointer after extent removal for RAID1
Naohiro Aota [Wed, 17 Dec 2025 11:14:04 +0000 (20:14 +0900)] 
btrfs: zoned: fixup last alloc pointer after extent removal for RAID1

When a block group is composed of a sequential write zone and a
conventional zone, we recover the (pseudo) write pointer of the
conventional zone using the end of the last allocated position.

However, if the last extent in a block group is removed, the last extent
position will be smaller than the other real write pointer position.
Then, that will cause an error due to mismatch of the write pointers.

We can fixup this case by moving the alloc_offset to the corresponding
write pointer position.

Fixes: 568220fa9657 ("btrfs: zoned: support RAID0/1/10 on top of raid stripe tree")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in btrfs_wait_for_commit()
Filipe Manana [Tue, 20 Jan 2026 20:07:32 +0000 (20:07 +0000)] 
btrfs: remove out label in btrfs_wait_for_commit()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in btrfs_init_space_info()
Filipe Manana [Tue, 20 Jan 2026 20:06:57 +0000 (20:06 +0000)] 
btrfs: remove out label in btrfs_init_space_info()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in btrfs_check_rw_degradable()
Filipe Manana [Tue, 20 Jan 2026 20:06:20 +0000 (20:06 +0000)] 
btrfs: remove out label in btrfs_check_rw_degradable()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in finish_verity()
Filipe Manana [Tue, 20 Jan 2026 20:05:43 +0000 (20:05 +0000)] 
btrfs: remove out label in finish_verity()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in scrub_find_fill_first_stripe()
Filipe Manana [Tue, 20 Jan 2026 20:05:02 +0000 (20:05 +0000)] 
btrfs: remove out label in scrub_find_fill_first_stripe()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in lzo_decompress()
Filipe Manana [Tue, 20 Jan 2026 20:04:26 +0000 (20:04 +0000)] 
btrfs: remove out label in lzo_decompress()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in btrfs_mark_extent_written()
Filipe Manana [Tue, 20 Jan 2026 20:03:45 +0000 (20:03 +0000)] 
btrfs: remove out label in btrfs_mark_extent_written()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in btrfs_csum_file_blocks()
Filipe Manana [Tue, 20 Jan 2026 20:02:51 +0000 (20:02 +0000)] 
btrfs: remove out label in btrfs_csum_file_blocks()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out_failed label in find_lock_delalloc_range()
Filipe Manana [Tue, 20 Jan 2026 20:01:31 +0000 (20:01 +0000)] 
btrfs: remove out_failed label in find_lock_delalloc_range()

There is no point in having the label since all it does is return the
value in the 'found' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove out label in load_extent_tree_free()
Filipe Manana [Tue, 20 Jan 2026 19:59:13 +0000 (19:59 +0000)] 
btrfs: remove out label in load_extent_tree_free()

There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 months agobtrfs: remove pointless out labels from uuid-tree.c
Filipe Manana [Tue, 20 Jan 2026 19:58:06 +0000 (19:58 +0000)] 
btrfs: remove pointless out labels from uuid-tree.c

Some functions (btrfs_uuid_iter_rem() and btrfs_check_uuid_tree_entry())
have an 'out' label that does nothing but return, making it pointless.
Simplify this by removing the label and returning instead of gotos plus
setting the 'ret' variable.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>