btrfs: Fixed declaration of old_len

old_len is used to store the return value of btrfs_item_size_nr(). The return value of btrfs_item_size_nr() is of type u32. To improve code correctness and avoid mixing signed and unsigned integers I've changed old_len to be of type u32 as well.

---
 fs/btrfs/root-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 360a728..024ea4f 100644
@@ -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)

2.5.0