btrfs: simplify cleanup after error in btrfs_create_tree

Since leaf is already NULL, and no other branch will go to fail_unlock,
the fail_unlock label is useless and can be removed
Signed-off-by: NPeng Hao <flyingpeng@tencent.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -1197,7 +1197,7 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 	if (IS_ERR(leaf)) {
 		ret = PTR_ERR(leaf);
 		leaf = NULL;
-		goto fail_unlock;
+		goto fail;
 	}
 
 	root->node = leaf;
@@ -1232,9 +1232,6 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 
 	return root;
 
-fail_unlock:
-	if (leaf)
-		btrfs_tree_unlock(leaf);
 fail:
 	btrfs_put_root(root);