vfs: make freeze_super abort when sync_filesystem returns error

BugLink: https://bugs.launchpad.net/bugs/1963890
[ 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>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/fs/super.c b/fs/super.c
index a1f82dfd1b39a3bd76a102709af77226f3b5e833..87379bb1f7a3029eeddac6f091933ec1c37f5e34 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -1616,11 +1616,9 @@ 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);
 }
 
@@ -1691,7 +1689,14 @@ 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;
@@ -1703,7 +1708,7 @@ 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;
@@ -1748,7 +1753,7 @@ 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);