bcachefs: add missing bch2_btree_iter_node_drop() call

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -819,14 +819,6 @@ void bch2_btree_iter_node_drop(struct btree_iter *iter, struct btree *b)
 	struct btree_iter *linked;
 	unsigned level = b->level;
 
-	/* caller now responsible for unlocking @b */
-
-	BUG_ON(iter->l[level].b != b);
-	BUG_ON(!btree_node_intent_locked(iter, level));
-
-	iter->l[level].b = BTREE_ITER_NOT_END;
-	mark_btree_node_unlocked(iter, level);
-
 	trans_for_each_iter(iter->trans, linked)
 		if (linked->l[level].b == b) {
 			__btree_node_unlock(linked, level);

fs/bcachefs/btree_update_interior.c

@@ -1429,6 +1429,7 @@ static void btree_split(struct btree_update *as, struct btree *b,
 
 	/* Successful split, update the iterator to point to the new nodes: */
 
+	six_lock_increment(&b->lock, SIX_LOCK_intent);
 	bch2_btree_iter_node_drop(iter, b);
 	if (n3)
 		bch2_btree_iter_node_replace(iter, n3);
@@ -1740,7 +1741,10 @@ void __bch2_foreground_maybe_merge(struct bch_fs *c,
 
 	bch2_open_buckets_put(c, &n->ob);
 
+	six_lock_increment(&b->lock, SIX_LOCK_intent);
 	bch2_btree_iter_node_drop(iter, b);
+	bch2_btree_iter_node_drop(iter, m);
+
 	bch2_btree_iter_node_replace(iter, n);
 
 	bch2_btree_iter_verify(iter, n);
@@ -1838,6 +1842,7 @@ static int __btree_node_rewrite(struct bch_fs *c, struct btree_iter *iter,
 
 	bch2_open_buckets_put(c, &n->ob);
 
+	six_lock_increment(&b->lock, SIX_LOCK_intent);
 	bch2_btree_iter_node_drop(iter, b);
 	bch2_btree_iter_node_replace(iter, n);
 	bch2_btree_node_free_inmem(c, b, iter);