<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/fs, branch v4.19.283</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v4.19.283</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v4.19.283'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2023-05-17T09:13:27+00:00</updated>
<entry>
<title>ext4: fix invalid free tracking in ext4_xattr_move_to_block()</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2023-04-30T07:04:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=f30f3391d089dc91aef91d08f4b04a6c0df2b067'/>
<id>urn:sha1:f30f3391d089dc91aef91d08f4b04a6c0df2b067</id>
<content type='text'>
commit b87c7cdf2bed4928b899e1ce91ef0d147017ba45 upstream.

In ext4_xattr_move_to_block(), the value of the extended attribute
which we need to move to an external block may be allocated by
kvmalloc() if the value is stored in an external inode.  So at the end
of the function the code tried to check if this was the case by
testing entry-&gt;e_value_inum.

However, at this point, the pointer to the xattr entry is no longer
valid, because it was removed from the original location where it had
been stored.  So we could end up calling kvfree() on a pointer which
was not allocated by kvmalloc(); or we could also potentially leak
memory by not freeing the buffer when it should be freed.  Fix this by
storing whether it should be freed in a separate variable.

Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230430160426.581366-1-tytso@mit.edu
Link: https://syzkaller.appspot.com/bug?id=5c2aee8256e30b55ccf57312c16d88417adbd5e1
Link: https://syzkaller.appspot.com/bug?id=41a6b5d4917c0412eb3b3c3c604965bed7d7420b
Reported-by: syzbot+64b645917ce07d89bde5@syzkaller.appspotmail.com
Reported-by: syzbot+0d042627c4f2ad332195@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>ext4: remove a BUG_ON in ext4_mb_release_group_pa()</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2023-04-29T20:14:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ef16d8a1798db1a1604ac44ca1bd73ec6bebf483'/>
<id>urn:sha1:ef16d8a1798db1a1604ac44ca1bd73ec6bebf483</id>
<content type='text'>
commit 463808f237cf73e98a1a45ff7460c2406a150a0b upstream.

If a malicious fuzzer overwrites the ext4 superblock while it is
mounted such that the s_first_data_block is set to a very large
number, the calculation of the block group can underflow, and trigger
a BUG_ON check.  Change this to be an ext4_warning so that we don't
crash the kernel.

Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230430154311.579720-3-tytso@mit.edu
Reported-by: syzbot+e2efa3efc15a1c9e95c3@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=69b28112e098b070f639efb356393af3ffec4220
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>ext4: bail out of ext4_xattr_ibody_get() fails for any reason</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2023-05-12T19:16:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c012309abecb6f9e2f628c0dbf7c74d06ef2640a'/>
<id>urn:sha1:c012309abecb6f9e2f628c0dbf7c74d06ef2640a</id>
<content type='text'>
commit 2a534e1d0d1591e951f9ece2fb460b2ff92edabd upstream.

In ext4_update_inline_data(), if ext4_xattr_ibody_get() fails for any
reason, it's best if we just fail as opposed to stumbling on,
especially if the failure is EFSCORRUPTED.

Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>ext4: add bounds checking in get_max_inline_xattr_value_size()</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2023-05-12T19:11:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3d7b8fbcd2273e2b9f4c6de5ce2f4c0cd3cb1205'/>
<id>urn:sha1:3d7b8fbcd2273e2b9f4c6de5ce2f4c0cd3cb1205</id>
<content type='text'>
commit 2220eaf90992c11d888fe771055d4de330385f01 upstream.

Normally the extended attributes in the inode body would have been
checked when the inode is first opened, but if someone is writing to
the block device while the file system is mounted, it's possible for
the inode table to get corrupted.  Add bounds checking to avoid
reading beyond the end of allocated memory if this happens.

Reported-by: syzbot+1966db24521e5f6e23f7@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=1966db24521e5f6e23f7
Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>ext4: improve error recovery code paths in __ext4_remount()</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2023-05-06T02:20:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=37302d4c2724dc92be5f90a3718eafa29834d586'/>
<id>urn:sha1:37302d4c2724dc92be5f90a3718eafa29834d586</id>
<content type='text'>
commit 4c0b4818b1f636bc96359f7817a2d8bab6370162 upstream.

If there are failures while changing the mount options in
__ext4_remount(), we need to restore the old mount options.

This commit fixes two problem.  The first is there is a chance that we
will free the old quota file names before a potential failure leading
to a use-after-free.  The second problem addressed in this commit is
if there is a failed read/write to read-only transition, if the quota
has already been suspended, we need to renable quota handling.

Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230506142419.984260-2-tytso@mit.edu
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>ext4: avoid a potential slab-out-of-bounds in ext4_group_desc_csum</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Tudor Ambarus</name>
<email>tudor.ambarus@linaro.org</email>
</author>
<published>2023-05-04T12:15:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a733c466cedd1013a41fd8908d5810f2c161072f'/>
<id>urn:sha1:a733c466cedd1013a41fd8908d5810f2c161072f</id>
<content type='text'>
commit 4f04351888a83e595571de672e0a4a8b74f4fb31 upstream.

When modifying the block device while it is mounted by the filesystem,
syzbot reported the following:

BUG: KASAN: slab-out-of-bounds in crc16+0x206/0x280 lib/crc16.c:58
Read of size 1 at addr ffff888075f5c0a8 by task syz-executor.2/15586

CPU: 1 PID: 15586 Comm: syz-executor.2 Not tainted 6.2.0-rc5-syzkaller-00205-gc96618275234 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
 print_address_description+0x74/0x340 mm/kasan/report.c:306
 print_report+0x107/0x1f0 mm/kasan/report.c:417
 kasan_report+0xcd/0x100 mm/kasan/report.c:517
 crc16+0x206/0x280 lib/crc16.c:58
 ext4_group_desc_csum+0x81b/0xb20 fs/ext4/super.c:3187
 ext4_group_desc_csum_set+0x195/0x230 fs/ext4/super.c:3210
 ext4_mb_clear_bb fs/ext4/mballoc.c:6027 [inline]
 ext4_free_blocks+0x191a/0x2810 fs/ext4/mballoc.c:6173
 ext4_remove_blocks fs/ext4/extents.c:2527 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2710 [inline]
 ext4_ext_remove_space+0x24ef/0x46a0 fs/ext4/extents.c:2958
 ext4_ext_truncate+0x177/0x220 fs/ext4/extents.c:4416
 ext4_truncate+0xa6a/0xea0 fs/ext4/inode.c:4342
 ext4_setattr+0x10c8/0x1930 fs/ext4/inode.c:5622
 notify_change+0xe50/0x1100 fs/attr.c:482
 do_truncate+0x200/0x2f0 fs/open.c:65
 handle_truncate fs/namei.c:3216 [inline]
 do_open fs/namei.c:3561 [inline]
 path_openat+0x272b/0x2dd0 fs/namei.c:3714
 do_filp_open+0x264/0x4f0 fs/namei.c:3741
 do_sys_openat2+0x124/0x4e0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_creat fs/open.c:1402 [inline]
 __se_sys_creat fs/open.c:1396 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1396
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f72f8a8c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f72f97e3168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f72f8bac050 RCX: 00007f72f8a8c0c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280
RBP: 00007f72f8ae7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd165348bf R14: 00007f72f97e3300 R15: 0000000000022000

Replace
	le16_to_cpu(sbi-&gt;s_es-&gt;s_desc_size)
with
	sbi-&gt;s_desc_size

It reduces ext4's compiled text size, and makes the code more efficient
(we remove an extra indirect reference and a potential byte
swap on big endian systems), and there is no downside. It also avoids the
potential KASAN / syzkaller failure, as a bonus.

Reported-by: syzbot+fc51227e7100c9294894@syzkaller.appspotmail.com
Reported-by: syzbot+8785e41224a3afd04321@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=70d28d11ab14bd7938f3e088365252aa923cff42
Link: https://syzkaller.appspot.com/bug?id=b85721b38583ecc6b5e72ff524c67302abbc30f3
Link: https://lore.kernel.org/all/000000000000ece18705f3b20934@google.com/
Fixes: 717d50e4971b ("Ext4: Uninitialized Block Groups")
Cc: stable@vger.kernel.org
Signed-off-by: Tudor Ambarus &lt;tudor.ambarus@linaro.org&gt;
Link: https://lore.kernel.org/r/20230504121525.3275886-1-tudor.ambarus@linaro.org
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>ext4: fix WARNING in mb_find_extent</title>
<updated>2023-05-17T09:13:27+00:00</updated>
<author>
<name>Ye Bin</name>
<email>yebin10@huawei.com</email>
</author>
<published>2023-01-16T02:00:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=775b00ba23f6f916fe2ac60c5ff7fd0fe4f28d0d'/>
<id>urn:sha1:775b00ba23f6f916fe2ac60c5ff7fd0fe4f28d0d</id>
<content type='text'>
commit fa08a7b61dff8a4df11ff1e84abfc214b487caf7 upstream.

Syzbot found the following issue:

EXT4-fs: Warning: mounting with data=journal disables delayed allocation, dioread_nolock, O_DIRECT and fast_commit support!
EXT4-fs (loop0): orphan cleanup on readonly fs
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5067 at fs/ext4/mballoc.c:1869 mb_find_extent+0x8a1/0xe30
Modules linked in:
CPU: 1 PID: 5067 Comm: syz-executor307 Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:mb_find_extent+0x8a1/0xe30 fs/ext4/mballoc.c:1869
RSP: 0018:ffffc90003c9e098 EFLAGS: 00010293
RAX: ffffffff82405731 RBX: 0000000000000041 RCX: ffff8880783457c0
RDX: 0000000000000000 RSI: 0000000000000041 RDI: 0000000000000040
RBP: 0000000000000040 R08: ffffffff82405723 R09: ffffed10053c9402
R10: ffffed10053c9402 R11: 1ffff110053c9401 R12: 0000000000000000
R13: ffffc90003c9e538 R14: dffffc0000000000 R15: ffffc90003c9e2cc
FS:  0000555556665300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056312f6796f8 CR3: 0000000022437000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 &lt;TASK&gt;
 ext4_mb_complex_scan_group+0x353/0x1100 fs/ext4/mballoc.c:2307
 ext4_mb_regular_allocator+0x1533/0x3860 fs/ext4/mballoc.c:2735
 ext4_mb_new_blocks+0xddf/0x3db0 fs/ext4/mballoc.c:5605
 ext4_ext_map_blocks+0x1868/0x6880 fs/ext4/extents.c:4286
 ext4_map_blocks+0xa49/0x1cc0 fs/ext4/inode.c:651
 ext4_getblk+0x1b9/0x770 fs/ext4/inode.c:864
 ext4_bread+0x2a/0x170 fs/ext4/inode.c:920
 ext4_quota_write+0x225/0x570 fs/ext4/super.c:7105
 write_blk fs/quota/quota_tree.c:64 [inline]
 get_free_dqblk+0x34a/0x6d0 fs/quota/quota_tree.c:130
 do_insert_tree+0x26b/0x1aa0 fs/quota/quota_tree.c:340
 do_insert_tree+0x722/0x1aa0 fs/quota/quota_tree.c:375
 do_insert_tree+0x722/0x1aa0 fs/quota/quota_tree.c:375
 do_insert_tree+0x722/0x1aa0 fs/quota/quota_tree.c:375
 dq_insert_tree fs/quota/quota_tree.c:401 [inline]
 qtree_write_dquot+0x3b6/0x530 fs/quota/quota_tree.c:420
 v2_write_dquot+0x11b/0x190 fs/quota/quota_v2.c:358
 dquot_acquire+0x348/0x670 fs/quota/dquot.c:444
 ext4_acquire_dquot+0x2dc/0x400 fs/ext4/super.c:6740
 dqget+0x999/0xdc0 fs/quota/dquot.c:914
 __dquot_initialize+0x3d0/0xcf0 fs/quota/dquot.c:1492
 ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
 ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5516 [inline]
 ext4_fill_super+0x81cd/0x8700 fs/ext4/super.c:5644
 get_tree_bdev+0x400/0x620 fs/super.c:1282
 vfs_get_tree+0x88/0x270 fs/super.c:1489
 do_new_mount+0x289/0xad0 fs/namespace.c:3145
 do_mount fs/namespace.c:3488 [inline]
 __do_sys_mount fs/namespace.c:3697 [inline]
 __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3674
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Add some debug information:
mb_find_extent: mb_find_extent block=41, order=0 needed=64 next=0 ex=0/41/1@3735929054 64 64 7
block_bitmap: ff 3f 0c 00 fc 01 00 00 d2 3d 00 00 00 00 00 00 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

Acctually, blocks per group is 64, but block bitmap indicate at least has
128 blocks. Now, ext4_validate_block_bitmap() didn't check invalid block's
bitmap if set.
To resolve above issue, add check like fsck "Padding at end of block bitmap is
not set".

Cc: stable@kernel.org
Reported-by: syzbot+68223fe9f6c95ad43bed@syzkaller.appspotmail.com
Signed-off-by: Ye Bin &lt;yebin10@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20230116020015.1506120-1-yebin@huaweicloud.com
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>cifs: fix pcchunk length type in smb2_copychunk_range</title>
<updated>2023-05-17T09:13:25+00:00</updated>
<author>
<name>Pawel Witek</name>
<email>pawel.ireneusz.witek@gmail.com</email>
</author>
<published>2023-05-05T15:14:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b7687d8ad13f3f0cd2addd2d679df0250eed48c5'/>
<id>urn:sha1:b7687d8ad13f3f0cd2addd2d679df0250eed48c5</id>
<content type='text'>
commit d66cde50c3c868af7abddafce701bb86e4a93039 upstream.

Change type of pcchunk-&gt;Length from u32 to u64 to match
smb2_copychunk_range arguments type. Fixes the problem where performing
server-side copy with CIFS_IOC_COPYCHUNK_FILE ioctl resulted in incomplete
copy of large files while returning -EINVAL.

Fixes: 9bf0c9cd4314 ("CIFS: Fix SMB2/SMB3 Copy offload support (refcopy) for large files")
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Pawel Witek &lt;pawel.ireneusz.witek@gmail.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>btrfs: print-tree: parent bytenr must be aligned to sector size</title>
<updated>2023-05-17T09:13:25+00:00</updated>
<author>
<name>Anastasia Belova</name>
<email>abelova@astralinux.ru</email>
</author>
<published>2023-04-26T11:53:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4199d58c73cf7f568c4f1e9c5192f4fda2afe22b'/>
<id>urn:sha1:4199d58c73cf7f568c4f1e9c5192f4fda2afe22b</id>
<content type='text'>
commit c87f318e6f47696b4040b58f460d5c17ea0280e6 upstream.

Check nodesize to sectorsize in alignment check in print_extent_item.
The comment states that and this is correct, similar check is done
elsewhere in the functions.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: ea57788eb76d ("btrfs: require only sector size alignment for parent eb bytenr")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo &lt;wqu@suse.com&gt;
Signed-off-by: Anastasia Belova &lt;abelova@astralinux.ru&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>btrfs: fix btrfs_prev_leaf() to not return the same key twice</title>
<updated>2023-05-17T09:13:25+00:00</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2023-04-12T10:33:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=561bf5cc3a0bb83cfbdabf03e5a1d69fcadb9cc5'/>
<id>urn:sha1:561bf5cc3a0bb83cfbdabf03e5a1d69fcadb9cc5</id>
<content type='text'>
commit 6f932d4ef007d6a4ae03badcb749fbb8f49196f6 upstream.

A call to btrfs_prev_leaf() may end up returning a path that points to the
same item (key) again. This happens if while btrfs_prev_leaf(), after we
release the path, a concurrent insertion happens, which moves items off
from a sibling into the front of the previous leaf, and an item with the
computed previous key does not exists.

For example, suppose we have the two following leaves:

  Leaf A

  -------------------------------------------------------------
  | ...   key (300 96 10)   key (300 96 15)   key (300 96 16) |
  -------------------------------------------------------------
              slot 20             slot 21             slot 22

  Leaf B

  -------------------------------------------------------------
  | key (300 96 20)   key (300 96 21)   key (300 96 22)   ... |
  -------------------------------------------------------------
      slot 0             slot 1             slot 2

If we call btrfs_prev_leaf(), from btrfs_previous_item() for example, with
a path pointing to leaf B and slot 0 and the following happens:

1) At btrfs_prev_leaf() we compute the previous key to search as:
   (300 96 19), which is a key that does not exists in the tree;

2) Then we call btrfs_release_path() at btrfs_prev_leaf();

3) Some other task inserts a key at leaf A, that sorts before the key at
   slot 20, for example it has an objectid of 299. In order to make room
   for the new key, the key at slot 22 is moved to the front of leaf B.
   This happens at push_leaf_right(), called from split_leaf().

   After this leaf B now looks like:

  --------------------------------------------------------------------------------
  | key (300 96 16)    key (300 96 20)   key (300 96 21)   key (300 96 22)   ... |
  --------------------------------------------------------------------------------
       slot 0              slot 1             slot 2             slot 3

4) At btrfs_prev_leaf() we call btrfs_search_slot() for the computed
   previous key: (300 96 19). Since the key does not exists,
   btrfs_search_slot() returns 1 and with a path pointing to leaf B
   and slot 1, the item with key (300 96 20);

5) This makes btrfs_prev_leaf() return a path that points to slot 1 of
   leaf B, the same key as before it was called, since the key at slot 0
   of leaf B (300 96 16) is less than the computed previous key, which is
   (300 96 19);

6) As a consequence btrfs_previous_item() returns a path that points again
   to the item with key (300 96 20).

For some users of btrfs_prev_leaf() or btrfs_previous_item() this may not
be functional a problem, despite not making sense to return a new path
pointing again to the same item/key. However for a caller such as
tree-log.c:log_dir_items(), this has a bad consequence, as it can result
in not logging some dir index deletions in case the directory is being
logged without holding the inode's VFS lock (logging triggered while
logging a child inode for example) - for the example scenario above, in
case the dir index keys 17, 18 and 19 were deleted in the current
transaction.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Signed-off-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
