bcachefs: Fix return code from btree_path_traverse_one()

trans->restarted is a positive error code, not the usual negative
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -1079,7 +1079,7 @@ static int btree_path_traverse_one(struct btree_trans *trans,
 				   unsigned long trace_ip)
 {
 	unsigned depth_want = path->level;
-	int ret = trans->restarted;
+	int ret = -((int) trans->restarted);
 
 	if (unlikely(ret))
 		goto out;

fs/bcachefs/btree_iter.h

@@ -359,6 +359,11 @@ __btree_iter_peek_node_and_restart(struct btree_trans *trans, struct btree_iter
 	return b;
 }
 
+/*
+ * XXX
+ * this does not handle transaction restarts from bch2_btree_iter_next_node()
+ * correctly
+ */
 #define __for_each_btree_node(_trans, _iter, _btree_id, _start,		\
 			      _locks_want, _depth, _flags, _b, _ret)	\
 	for (bch2_trans_node_iter_init((_trans), &(_iter), (_btree_id),	\