[f2fs-dev] [PATCH v2] f2fs: quota: fix stale lock holder on remount failure

[f2fs-dev] [PATCH v2] f2fs: quota: fix stale lock holder on remount failure

[Jianan Huang]

F2FS remount can fail while duplicating a journalled quota file name.

f2fs_remount()
- sbi->umount_lock_holder = current
- kstrdup(F2FS_OPTION(sbi).s_qf_names[i])
  : fails
- free previously duplicated names
- return -ENOMEM

The direct return leaves umount_lock_holder pointing at the failed
remount context.  A later checkpoint may then wrongly treat another
context as the s_umount lock holder.

Add a restore_holder cleanup path and use it before returning -ENOMEM.

Fixes: eb85c2410d6f ("f2fs: quota: fix to avoid warning in dquot_writeback_dquots()")
Signed-off-by: Jianan Huang <jnhuang95@gmail.com>
---
Changes since v1:
- add restore_holder cleanup label.

 fs/f2fs/super.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1314b6ccced9..867c82192078 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2864,7 +2864,8 @@ static int __f2fs_remount(struct fs_context *fc, struct super_block *sb)
 			if (!org_mount_opt.s_qf_names[i]) {
 				for (j = 0; j < i; j++)
 					kfree(org_mount_opt.s_qf_names[j]);
-				return -ENOMEM;
+				err = -ENOMEM;
+				goto restore_holder;
 			}
 		} else {
 			org_mount_opt.s_qf_names[i] = NULL;
@@ -3125,6 +3126,7 @@ static int __f2fs_remount(struct fs_context *fc, struct super_block *sb)
 	sbi->mount_opt = org_mount_opt;
 	sb->s_flags = old_sb_flags;
 
+restore_holder:
 	sbi->umount_lock_holder = NULL;
 	return err;
 }
-- 
2.43.0



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Re: [f2fs-dev] [PATCH v2] f2fs: quota: fix stale lock holder on remount failure

[Chao Yu via Linux-f2fs-devel]

On 9/9/26 19:46, Jianan Huang wrote:
> F2FS remount can fail while duplicating a journalled quota file name.
> 
> f2fs_remount()
> - sbi->umount_lock_holder = current
> - kstrdup(F2FS_OPTION(sbi).s_qf_names[i])
>   : fails
> - free previously duplicated names
> - return -ENOMEM
> 
> The direct return leaves umount_lock_holder pointing at the failed
> remount context.  A later checkpoint may then wrongly treat another
> context as the s_umount lock holder.
> 
> Add a restore_holder cleanup path and use it before returning -ENOMEM.
> 
> Fixes: eb85c2410d6f ("f2fs: quota: fix to avoid warning in dquot_writeback_dquots()")
> Signed-off-by: Jianan Huang <jnhuang95@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,


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Re: [f2fs-dev] [PATCH v2] f2fs: quota: fix stale lock holder on remount failure

[patchwork-bot+f2fs--- via Linux-f2fs-devel]

Hello:

This patch was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:

On Wed,  9 Sep 2026 19:46:14 +0800 you wrote:
> F2FS remount can fail while duplicating a journalled quota file name.
> 
> f2fs_remount()
> - sbi->umount_lock_holder = current
> - kstrdup(F2FS_OPTION(sbi).s_qf_names[i])
>   : fails
> - free previously duplicated names
> - return -ENOMEM
> 
> [...]

Here is the summary with links:
  - [f2fs-dev,v2] f2fs: quota: fix stale lock holder on remount failure
    https://git.kernel.org/jaegeuk/f2fs/c/3f140a60c92a

You are awesome, thank you!
-- 
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