diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 360a728a639fec403893c6847e1f7859a47dff13..024ea4fb33036ed33ef191a4f61a7606455cea52 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -141,7 +141,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 	int ret;
 	int slot;
 	unsigned long ptr;
-	int old_len;
+	u32 old_len;
 
 	path = btrfs_alloc_path();
 	if (!path)