diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c
index 6e4afb2b5441..63fc59742a13 100644
--- a/fs/bcachefs/btree_cache.c
+++ b/fs/bcachefs/btree_cache.c
@@ -880,13 +880,18 @@ static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans,
 	struct bch_fs *c = trans->c;
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b;
-
 	if (unlikely(level >= BTREE_MAX_DEPTH)) {
 		int ret = bch2_fs_topology_error(c, "attempting to get btree node at level %u, >= max depth %u",
 						 level, BTREE_MAX_DEPTH);
 		return ERR_PTR(ret);
 	}
 
+	if (unlikely(btree_id >= BTREE_ID_NR_MAX)) {
+		int ret = bch2_fs_topology_error(c, "invalid btree id %u (max %u)",
+				btree_id, BTREE_ID_NR_MAX);
+		return ERR_PTR(ret);
+	}
+
 	if (unlikely(!bkey_is_btree_ptr(&k->k))) {
 		struct printbuf buf = PRINTBUF;
 		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k));