ftl: return -1 when no root could be found

source/ftl/map.c

@@ -286,15 +286,17 @@ static int find_root(struct ftl_map *map, uint32_t group)
 {
 	struct ftl_page_desc page_desc;
 	uint32_t upage;
+	int ret = -1;
 
 	upage = group << map->log2_pages_per_group;
 
 	while (read_page_desc(map, &page_desc, upage) == 0) {
 		map->root = upage;
+		ret = 0;
 		upage = next_upage(map, upage);
 	}
 
-	return 0;
+	return ret;
 }
 
 /* Attempts to find the first free page within a page group by looking for the