diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index cf32651876bf970abb78bb963ff3f8b522eb7554..ef8809c1e69c3896655a64ee43d6713f7fc1f3ab 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -720,6 +720,9 @@ static int balance_level(struct btrfs_trans_handle *trans,
 		/* promote the child to a root */
 		child = read_node_slot(root, mid, 0);
 		BUG_ON(!child);
+		ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
+		BUG_ON(ret);
+
 		root->node = child;
 		path->nodes[level] = NULL;
 		clean_tree_block(trans, root, mid);