Btrfs: fix warning when creating snapshots

Creating snapshot passes extent_root to commit its transaction,
but it can lead to the warning of checking root for quota in
the __btrfs_end_transaction() when someone else is committing
the current transaction.  Since we've recorded the needed root
in trans_handle, just use it to get rid of the warning.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index fedede1fe178..c4a1531c52d8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -626,14 +626,13 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 
         btrfs_trans_release_metadata(trans, root);
         trans->block_rsv = NULL;
-        /*
-         * the same root has to be passed to start_transaction and
-         * end_transaction. Subvolume quota depends on this.
-         */
-        WARN_ON(trans->root != root);
 
         if (trans->qgroup_reserved) {
-                btrfs_qgroup_free(root, trans->qgroup_reserved);
+                /*
+                 * the same root has to be passed here between start_transaction
+                 * and end_transaction. Subvolume quota depends on this.
+                 */
+                btrfs_qgroup_free(trans->root, trans->qgroup_reserved);
                 trans->qgroup_reserved = 0;
         }