freeze_bdev() will bail but leave the bd_fsfreeze_count incremented
if the get_active_super() does not find the superblock on our
super_blocks list to match.
This issue has been present since v2.6.29 during the introduction of the
ioctl_fsfreeze() and ioctl_fsthaw() via commit fcccf502540e3 ("filesystem
freeze: implement generic freeze feature").
I am not aware of any existing races which have triggered this
situation, however, if it does trigger it could mean leaving a
superblock with bd_fsfreeze_count always positive.
Fixes: fcccf502540e3 ("filesystem freeze: implement generic freeze feature")
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
---
fs/block_dev.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b54966679833..7a532aa58c07 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -507,8 +507,10 @@ struct super_block *freeze_bdev(struct block_device *bdev)
}
sb = get_active_super(bdev);
- if (!sb)
+ if (!sb) {
+ bdev->bd_fsfreeze_count--;
goto out;
+ }
if (sb->s_op->freeze_super)
error = sb->s_op->freeze_super(sb);
else
--
2.16.3
