linux-stable.git/fs/fat/misc.c, branch linux-rolling-lts

fat: restore original value when fat_ent_write failed

2026-09-07T15:22:34+00:00

commit 64d9183203eebe33de6188b70a8c1e91f52885db upstream.

fat_ent_write() may have committed the new link to the primary FAT but
then failed on the mirror copy, leaving the chain pointing to new_dclus
even though the caller will free it.  Restore the original value to keep
the chain consistent.

Link: https://lore.kernel.org/20260525085649.781643-1-n05ec@lzu.edu.cn
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Yemu Lu 
Signed-off-by: Ren Wei 
Reported-by: Yuan Tan 
Reported-by: Yifan Wu 
Reported-by: Juefei Pu 
Reported-by: Xin Liu 
Acked-by: OGAWA Hirofumi 
Cc: Christian Brauner 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

fat: fix too many log in fat_chain_add()

2025-08-02T19:01:40+00:00

This log was excessive for a serial console.  So use the ratelimited
version instead.

Link: https://lkml.kernel.org/r/87qzy611d9.fsf@mail.parknet.co.jp
Signed-off-by: OGAWA Hirofumi 
Reported-by: syzbot+fa7ef54f66c189c04b73@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=fa7ef54f66c189c04b73
Cc: Namjae Jeon 
Cc: Sungjong Seo 
Signed-off-by: Andrew Morton

fat: convert to new timestamp accessors

2023-10-18T12:08:03+00:00

Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20231004185347.80880-35-jlayton@kernel.org
Tested-by: Klara Modin 
Signed-off-by: Christian Brauner

fs: drop the timespec64 argument from update_time

2023-08-11T07:04:57+00:00

Now that all of the update_time operations are prepared for it, we can
drop the timespec64 argument from the update_time operation. Do that and
remove it from some associated functions like inode_update_time and
inode_needs_update_time.

Signed-off-by: Jeff Layton 
Reviewed-by: Jan Kara 
Message-Id: <20230807-mgctime-v7-8-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner

fat: make fat_update_time get its own timestamp

2023-08-11T07:04:56+00:00

In later patches, we're going to drop the "now" parameter from the
update_time operation. Fix fat_update_time to fetch its own timestamp.
It turns out that this is easily done by just passing a NULL timestamp
pointer to fat_truncate_time.

Signed-off-by: Jeff Layton 
Acked-by: OGAWA Hirofumi 
Reviewed-by: Jan Kara 
Reviewed-by: Frank Sorenson 
Message-Id: <20230810-ctime-fat-v1-2-327598fd1de8@kernel.org>
Signed-off-by: Christian Brauner

fat: remove i_version handling from fat_update_time

2023-08-11T07:04:56+00:00

commit 6bb885ecd746 (fat: add functions to update and truncate
timestamps appropriately") added an update_time routine for fat. That
patch added a section for handling the S_VERSION bit, even though FAT
doesn't enable SB_I_VERSION and the S_VERSION bit will never be set when
calling it.

Remove the section for handling S_VERSION since it's effectively dead
code, and will be problematic vs. future changes.

Cc: Frank Sorenson 
Signed-off-by: Jeff Layton 
Acked-by: OGAWA Hirofumi 
Reviewed-by: Jan Kara 
Reviewed-by: Frank Sorenson 
Message-Id: <20230810-ctime-fat-v1-1-327598fd1de8@kernel.org>
Signed-off-by: Christian Brauner

fat: convert to ctime accessor functions

2023-07-24T08:29:59+00:00

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Signed-off-by: Jeff Layton 
Message-Id: <20230705190309.579783-42-jlayton@kernel.org>
Signed-off-by: Christian Brauner

fat: remove time truncations in vfat_create/vfat_mkdir

2022-05-19T21:10:31+00:00

All the timestamps in vfat_create() and vfat_mkdir() come from
fat_time_fat2unix() which ensures time granularity.  We don't need to
truncate them to fit FAT's format.

Moreover, fat_truncate_crtime() and fat_timespec64_trunc_10ms() are also
removed because there is no caller anymore.

Link: https://lkml.kernel.org/r/20220503152536.2503003-4-cccheng@synology.com
Signed-off-by: Chung-Chiang Cheng 
Acked-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton

fat: ignore ctime updates, and keep ctime identical to mtime in memory

2022-05-19T21:10:31+00:00

FAT supports creation time but not change time, and there was no
corresponding timestamp for creation time in previous VFS.  The original
implementation took the compromise of saving the in-memory change time
into the on-disk creation time field, but this would lead to compatibility
issues with non-linux systems.

To address this issue, this patch changes the behavior of ctime.  It will
no longer be loaded and stored from the creation time on disk.  Instead of
that, it'll be consistent with the in-memory mtime and share the same
on-disk field.  All updates to mtime will also be applied to ctime in
memory, while all updates to ctime will be ignored.

Link: https://lkml.kernel.org/r/20220503152536.2503003-2-cccheng@synology.com
Signed-off-by: Chung-Chiang Cheng 
Acked-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton

fat: split fat_truncate_time() into separate functions

2022-05-19T21:10:31+00:00

Separate fat_truncate_time() to each timestamps for later creation time
work.

This patch does not introduce any functional changes, it's merely
refactoring change.

Link: https://lkml.kernel.org/r/20220503152536.2503003-1-cccheng@synology.com
Signed-off-by: Chung-Chiang Cheng 
Acked-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton