49 	struct list_head lower;  member
224 				  struct backref_node, lower);  in backref_cache_cleanup()
247 		INIT_LIST_HEAD(&node->lower);  in alloc_backref_node()
365 	struct backref_node *lower;  in walk_down_backref()  local
370 		lower = edge->node[LOWER];  in walk_down_backref()
371 		if (list_is_last(&edge->list[LOWER], &lower->upper)) {  in walk_down_backref()
409 	list_del(&node->lower);  in drop_backref_node()
447 		if (list_empty(&upper->lower)) {  in remove_backref_node()
448 			list_add_tail(&upper->lower, &cache->leaves);  in remove_backref_node()
661 	struct backref_node *lower;  in build_backref_tree()  local
904 		lower = cur;  in build_backref_tree()
911 				       lower->bytenr);  in build_backref_tree()
913 					list_add(&lower->list, &useless);  in build_backref_tree()
915 					lower->root = root;  in build_backref_tree()
936 				upper->level = lower->level + 1;  in build_backref_tree()
973 			list_add_tail(&edge->list[LOWER], &lower->upper);  in build_backref_tree()
974 			edge->node[LOWER] = lower;  in build_backref_tree()
979 			lower = upper;  in build_backref_tree()
1019 		list_add_tail(&node->lower, &cache->leaves);  in build_backref_tree()
1031 			lower = edge->node[LOWER];  in build_backref_tree()
1033 			if (list_empty(&lower->upper))  in build_backref_tree()
1034 				list_add(&lower->list, &useless);  in build_backref_tree()
1040 				list_del_init(&upper->lower);  in build_backref_tree()
1044 			list_add_tail(&edge->list[UPPER], &upper->lower);  in build_backref_tree()
1071 		list_add_tail(&edge->list[UPPER], &upper->lower);  in build_backref_tree()
1089 			list_del_init(&upper->lower);  in build_backref_tree()
1092 		while (!list_empty(&upper->lower)) {  in build_backref_tree()
1093 			edge = list_entry(upper->lower.next,  in build_backref_tree()
1097 			lower = edge->node[LOWER];  in build_backref_tree()
1100 			if (list_empty(&lower->upper))  in build_backref_tree()
1101 				list_add(&lower->list, &useless);  in build_backref_tree()
1117 			lower = list_entry(useless.next,  in build_backref_tree()
1119 			list_del_init(&lower->list);  in build_backref_tree()
1126 			lower = edge->node[LOWER];  in build_backref_tree()
1134 			if (list_empty(&lower->upper) &&  in build_backref_tree()
1135 			    RB_EMPTY_NODE(&lower->rb_node))  in build_backref_tree()
1136 				list_add(&lower->list, &useless);  in build_backref_tree()
1149 			lower = list_entry(useless.next,  in build_backref_tree()
1151 			list_del_init(&lower->list);  in build_backref_tree()
1152 			if (lower == node)  in build_backref_tree()
1154 			free_backref_node(cache, lower);  in build_backref_tree()
1218 		list_for_each_entry(edge, &node->lower, list[UPPER]) {  in clone_backref_node()
1226 				      &new_node->lower);  in clone_backref_node()
1229 		list_add_tail(&new_node->lower, &cache->leaves);  in clone_backref_node()
1238 		list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {  in clone_backref_node()
1245 	while (!list_empty(&new_node->lower)) {  in clone_backref_node()
1246 		new_edge = list_entry(new_node->lower.next,  in clone_backref_node()