(BTREE_FOREGROUND_MERGE_THRESHOLD(c) + \
(BTREE_FOREGROUND_MERGE_THRESHOLD(c) << 2))
-#define btree_node_root(_c, _b) ((_c)->btree_roots[(_b)->btree_id].b)
+#define btree_node_root(_c, _b) ((_c)->btree_roots[(_b)->c.btree_id].b)
void bch2_btree_node_to_text(struct printbuf *, struct bch_fs *,
struct btree *);