linux-stable.git/fs/ext4/super.c, branch linux-5.4.y

ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()

2025-10-29T13:00:01+00:00

[ Upstream commit 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 ]

Unlike other strings in the ext4 superblock, we rely on tune2fs to
make sure s_mount_opts is NUL terminated.  Harden
parse_apply_sb_mount_options() by treating s_mount_opts as a potential
__nonstring.

Cc: stable@vger.kernel.org
Fixes: 8b67f04ab9de ("ext4: Add mount options in superblock")
Reviewed-by: Jan Kara 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Theodore Ts'o 
Message-ID: <20250916-tune2fs-v2-1-d594dc7486f0@mit.edu>
Signed-off-by: Theodore Ts'o 
[ applied to ext4_fill_super() instead of parse_apply_sb_mount_options() ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ext4: don't over-report free space or inodes in statvfs

2025-05-02T05:39:24+00:00

[ Upstream commit f87d3af7419307ae26e705a2b2db36140db367a2 ]

This fixes an analogus bug that was fixed in xfs in commit
4b8d867ca6e2 ("xfs: don't over-report free space or inodes in
statvfs") where statfs can report misleading / incorrect information
where project quota is enabled, and the free space is less than the
remaining quota.

This commit will resolve a test failure in generic/762 which tests for
this bug.

Cc: stable@kernel.org
Fixes: 689c958cbe6b ("ext4: add project quota support")
Signed-off-by: Theodore Ts'o 
Reviewed-by: "Darrick J. Wong" 
Signed-off-by: Sasha Levin

ext4: code cleanup for ext4_statfs_project()

2025-05-02T05:39:24+00:00

[ Upstream commit a08fe66e4a0e12a3df982b28059f3a90e0f1b31e ]

Calling min_not_zero() to simplify complicated prjquota
limit comparison in ext4_statfs_project().

Signed-off-by: Chengguang Xu 
Link: https://lore.kernel.org/r/20200210082445.2379-1-cgxu519@mykernel.net
Signed-off-by: Theodore Ts'o 
Stable-dep-of: f87d3af74193 ("ext4: don't over-report free space or inodes in statvfs")
Signed-off-by: Sasha Levin

ext4: simplify checking quota limits in ext4_statfs()

2025-05-02T05:39:24+00:00

[ Upstream commit 46d36880d1c6f9b9a0cbaf90235355ea1f4cab96 ]

Coverity reports that conditions checking quota limits in ext4_statfs()
contain dead code. Indeed it is right and current conditions can be
simplified.

Link: https://lore.kernel.org/r/20200130111148.10766-1-jack@suse.cz
Reported-by: Coverity 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Stable-dep-of: f87d3af74193 ("ext4: don't over-report free space or inodes in statvfs")
Signed-off-by: Sasha Levin

ext4: protect ext4_release_dquot against freezing

2025-05-02T05:39:11+00:00

[ Upstream commit 530fea29ef82e169cd7fe048c2b7baaeb85a0028 ]

Protect ext4_release_dquot against freezing so that we
don't try to start a transaction when FS is frozen, leading
to warnings.

Further, avoid taking the freeze protection if a transaction
is already running so that we don't need end up in a deadlock
as described in

  46e294efc355 ext4: fix deadlock with fs freezing and EA inodes

Suggested-by: Jan Kara 
Signed-off-by: Ojaswin Mujoo 
Reviewed-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20241121123855.645335-3-ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: supress data-race warnings in ext4_free_inodes_{count,set}()

2024-12-14T18:44:35+00:00

commit 902cc179c931a033cd7f4242353aa2733bf8524c upstream.

find_group_other() and find_group_orlov() read *_lo, *_hi with
ext4_free_inodes_count without additional locking. This can cause
data-race warning, but since the lock is held for most writes and free
inodes value is generally not a problem even if it is incorrect, it is
more appropriate to use READ_ONCE()/WRITE_ONCE() than to add locking.

==================================================================
BUG: KCSAN: data-race in ext4_free_inodes_count / ext4_free_inodes_set

write to 0xffff88810404300e of 2 bytes by task 6254 on cpu 1:
 ext4_free_inodes_set+0x1f/0x80 fs/ext4/super.c:405
 __ext4_new_inode+0x15ca/0x2200 fs/ext4/ialloc.c:1216
 ext4_symlink+0x242/0x5a0 fs/ext4/namei.c:3391
 vfs_symlink+0xca/0x1d0 fs/namei.c:4615
 do_symlinkat+0xe3/0x340 fs/namei.c:4641
 __do_sys_symlinkat fs/namei.c:4657 [inline]
 __se_sys_symlinkat fs/namei.c:4654 [inline]
 __x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4654
 x64_sys_call+0x1dda/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:267
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

read to 0xffff88810404300e of 2 bytes by task 6257 on cpu 0:
 ext4_free_inodes_count+0x1c/0x80 fs/ext4/super.c:349
 find_group_other fs/ext4/ialloc.c:594 [inline]
 __ext4_new_inode+0x6ec/0x2200 fs/ext4/ialloc.c:1017
 ext4_symlink+0x242/0x5a0 fs/ext4/namei.c:3391
 vfs_symlink+0xca/0x1d0 fs/namei.c:4615
 do_symlinkat+0xe3/0x340 fs/namei.c:4641
 __do_sys_symlinkat fs/namei.c:4657 [inline]
 __se_sys_symlinkat fs/namei.c:4654 [inline]
 __x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4654
 x64_sys_call+0x1dda/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:267
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Cc: stable@vger.kernel.org
Signed-off-by: Jeongjun Park 
Reviewed-by: Andreas Dilger 
Link: https://patch.msgid.link/20241003125337.47283-1-aha310510@gmail.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: Fix reusing stale buffer heads from last failed mounting

2023-08-11T09:53:44+00:00

[ Upstream commit 26fb5290240dc31cae99b8b4dd2af7f46dfcba6b ]

Following process makes ext4 load stale buffer heads from last failed
mounting in a new mounting operation:
mount_bdev
 ext4_fill_super
 | ext4_load_and_init_journal
 |  ext4_load_journal
 |   jbd2_journal_load
 |    load_superblock
 |     journal_get_superblock
 |      set_buffer_verified(bh) // buffer head is verified
 |   jbd2_journal_recover // failed caused by EIO
 | goto failed_mount3a // skip 'sb->s_root' initialization
 deactivate_locked_super
  kill_block_super
   generic_shutdown_super
    if (sb->s_root)
    // false, skip ext4_put_super->invalidate_bdev->
    // invalidate_mapping_pages->mapping_evict_folio->
    // filemap_release_folio->try_to_free_buffers, which
    // cannot drop buffer head.
   blkdev_put
    blkdev_put_whole
     if (atomic_dec_and_test(&bdev->bd_openers))
     // false, systemd-udev happens to open the device. Then
     // blkdev_flush_mapping->kill_bdev->truncate_inode_pages->
     // truncate_inode_folio->truncate_cleanup_folio->
     // folio_invalidate->block_invalidate_folio->
     // filemap_release_folio->try_to_free_buffers will be skipped,
     // dropping buffer head is missed again.

Second mount:
ext4_fill_super
 ext4_load_and_init_journal
  ext4_load_journal
   ext4_get_journal
    jbd2_journal_init_inode
     journal_init_common
      bh = getblk_unmovable
       bh = __find_get_block // Found stale bh in last failed mounting
      journal->j_sb_buffer = bh
   jbd2_journal_load
    load_superblock
     journal_get_superblock
      if (buffer_verified(bh))
      // true, skip journal->j_format_version = 2, value is 0
    jbd2_journal_recover
     do_one_pass
      next_log_block += count_tags(journal, bh)
      // According to journal_tag_bytes(), 'tag_bytes' calculating is
      // affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3()
      // returns false because 'j->j_format_version >= 2' is not true,
      // then we get wrong next_log_block. The do_one_pass may exit
      // early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'.

The filesystem is corrupted here, journal is partially replayed, and
new journal sequence number actually is already used by last mounting.

The invalidate_bdev() can drop all buffer heads even racing with bare
reading block device(eg. systemd-udev), so we can fix it by invalidating
bdev in error handling path in __ext4_fill_super().

Fetch a reproducer in [Link].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171
Fixes: 25ed6e8a54df ("jbd2: enable journal clients to enable v2 checksumming")
Cc: stable@vger.kernel.org # v3.5
Signed-off-by: Zhihao Cheng 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20230315013128.3911115-2-chengzhihao1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: rename journal_dev to s_journal_dev inside ext4_sb_info

2023-08-11T09:53:44+00:00

[ Upstream commit ee7ed3aa0f08621dbf897d2a98dc6f2c7e7d0335 ]

Rename journal_dev to s_journal_dev inside ext4_sb_info, keep
the naming rules consistent with other variables, which is
convenient for code reading and writing.

Signed-off-by: Chunguang Xu 
Reviewed-by: Andreas Dilger 
Reviewed-by: Ritesh Harjani 
Link: https://lore.kernel.org/r/1600916623-544-1-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: 26fb5290240d ("ext4: Fix reusing stale buffer heads from last failed mounting")
Signed-off-by: Sasha Levin

ext4: improve error recovery code paths in __ext4_remount()

2023-05-17T09:36:03+00:00

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 
Signed-off-by: Greg Kroah-Hartman

ext4: avoid a potential slab-out-of-bounds in ext4_group_desc_csum

2023-05-17T09:36:03+00:00

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:
 
 __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 <48> 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->s_es->s_desc_size)
with
	sbi->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 
Link: https://lore.kernel.org/r/20230504121525.3275886-1-tudor.ambarus@linaro.org
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman