[PATCH AUTOSEL 5.10 14/27] vfs: make freeze_super abort when sync_filesystem returns error

Sasha Levin
2022-02-09T18:44:21Z

From: "Darrick J. Wong" <djwong@kernel.org>

[ Upstream commit 2719c7160dcfaae1f73a1c0c210ad3281c19022e ]

If we fail to synchronize the filesystem while preparing to freeze the
fs, abort the freeze.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/super.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/super.c b/fs/super.c
index 20f1707807bbd..bae3fe80f852e 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1667,11 +1667,9 @@ static void lockdep_sb_freeze_acquire(struct super_block *sb)
percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
}

-static void sb_freeze_unlock(struct super_block *sb)
+static void sb_freeze_unlock(struct super_block *sb, int level)
{
- int level;
-
- for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--)
+ for (level--; level >= 0; level--)
percpu_up_write(sb->s_writers.rw_sem + level);
}

@@ -1742,7 +1740,14 @@ int freeze_super(struct super_block *sb)
sb_wait_write(sb, SB_FREEZE_PAGEFAULT);

/* All writers are done so after syncing there won't be dirty data */
- sync_filesystem(sb);
+ ret = sync_filesystem(sb);
+ if (ret) {
+ sb->s_writers.frozen = SB_UNFROZEN;
+ sb_freeze_unlock(sb, SB_FREEZE_PAGEFAULT);
+ wake_up(&sb->s_writers.wait_unfrozen);
+ deactivate_locked_super(sb);
+ return ret;
+ }

/* Now wait for internal filesystem counter */
sb->s_writers.frozen = SB_FREEZE_FS;
@@ -1754,7 +1759,7 @@ int freeze_super(struct super_block *sb)
printk(KERN_ERR
"VFS:Filesystem freeze failed\n");
sb->s_writers.frozen = SB_UNFROZEN;
- sb_freeze_unlock(sb);
+ sb_freeze_unlock(sb, SB_FREEZE_FS);
wake_up(&sb->s_writers.wait_unfrozen);
deactivate_locked_super(sb);
return ret;
@@ -1805,7 +1810,7 @@ static int thaw_super_locked(struct super_block *sb)
}

sb->s_writers.frozen = SB_UNFROZEN;
- sb_freeze_unlock(sb);
+ sb_freeze_unlock(sb, SB_FREEZE_FS);
out:
wake_up(&sb->s_writers.wait_unfrozen);
deactivate_locked_super(sb);
--
2.34.1