Btrfs: fix lockdep warning

The locking order for stuff is

__sb_start_write
ordered_mutex

but with sync() we don't do __sb_start_write for some strange reason, which
means that our iput in wait_ordered_extents could start a transaction which does
the __sb_start_write while we're holding the ordered_mutex.  Fix this by using
delayed iput in sync.  Thanks,

Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5dc54ae..a4807ce 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -866,7 +866,7 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
                return 0;
        }
 
-       btrfs_wait_ordered_extents(root, 0);
+       btrfs_wait_ordered_extents(root, 1);
 
        trans = btrfs_attach_transaction_barrier(root);
        if (IS_ERR(trans)) {