56 	struct list_head upper;  member
253 		INIT_LIST_HEAD(&node->upper);  in alloc_backref_node()
353 	while (!list_empty(&node->upper)) {  in walk_up_backref()
354 		edge = list_entry(node->upper.next,  in walk_up_backref()
377 		if (list_is_last(&edge->list[LOWER], &lower->upper)) {  in walk_down_backref()
411 	BUG_ON(!list_empty(&node->upper));  in drop_backref_node()
427 	struct backref_node *upper;  in remove_backref_node()  local
434 	while (!list_empty(&node->upper)) {  in remove_backref_node()
435 		edge = list_entry(node->upper.next, struct backref_edge,  in remove_backref_node()
437 		upper = edge->node[UPPER];  in remove_backref_node()
442 		if (RB_EMPTY_NODE(&upper->rb_node)) {  in remove_backref_node()
443 			BUG_ON(!list_empty(&node->upper));  in remove_backref_node()
445 			node = upper;  in remove_backref_node()
453 		if (list_empty(&upper->lower)) {  in remove_backref_node()
454 			list_add_tail(&upper->lower, &cache->leaves);  in remove_backref_node()
455 			upper->lowest = 1;  in remove_backref_node()
689 	struct backref_node *upper;  local
745 	if (!list_empty(&cur->upper)) {
750 		ASSERT(list_is_singular(&cur->upper));
751 		edge = list_entry(cur->upper.next, struct backref_edge,
856 				upper = alloc_backref_node(cache);
857 				if (!upper) {
862 				upper->bytenr = key.offset;
863 				upper->level = cur->level + 1;
870 				upper = rb_entry(rb_node, struct backref_node,
872 				ASSERT(upper->checked);
875 			list_add_tail(&edge->list[LOWER], &cur->upper);
877 			edge->node[UPPER] = upper;
949 				upper = alloc_backref_node(cache);
950 				if (!upper) {
955 				upper->bytenr = eb->start;
956 				upper->owner = btrfs_header_owner(eb);
957 				upper->level = lower->level + 1;
960 					upper->cowonly = 1;
967 					upper->checked = 0;
969 					upper->checked = 1;
977 				if (!upper->checked && need_check) {
982 					if (upper->checked)
987 				upper = rb_entry(rb_node, struct backref_node,
989 				ASSERT(upper->checked);
991 				if (!upper->owner)
992 					upper->owner = btrfs_header_owner(eb);
994 			list_add_tail(&edge->list[LOWER], &lower->upper);
996 			edge->node[UPPER] = upper;
1000 			lower = upper;
1001 			upper = NULL;
1043 	list_for_each_entry(edge, &node->upper, list[LOWER])
1049 		upper = edge->node[UPPER];
1050 		if (upper->detached) {
1054 			if (list_empty(&lower->upper))
1059 		if (!RB_EMPTY_NODE(&upper->rb_node)) {
1060 			if (upper->lowest) {
1061 				list_del_init(&upper->lower);
1062 				upper->lowest = 0;
1065 			list_add_tail(&edge->list[UPPER], &upper->lower);
1069 		if (!upper->checked) {
1078 		if (cowonly != upper->cowonly) {
1085 			rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1086 					      &upper->rb_node);
1089 						   upper->bytenr);
1092 		list_add_tail(&edge->list[UPPER], &upper->lower);
1094 		list_for_each_entry(edge, &upper->upper, list[LOWER])
1104 		upper = list_entry(useless.next, struct backref_node, list);
1105 		list_del_init(&upper->list);
1106 		ASSERT(list_empty(&upper->upper));
1107 		if (upper == node)
1109 		if (upper->lowest) {
1110 			list_del_init(&upper->lower);
1111 			upper->lowest = 0;
1113 		while (!list_empty(&upper->lower)) {
1114 			edge = list_entry(upper->lower.next,
1121 			if (list_empty(&lower->upper))
1124 		__mark_block_processed(rc, upper);
1125 		if (upper->level > 0) {
1126 			list_add(&upper->list, &cache->detached);
1127 			upper->detached = 1;
1129 			rb_erase(&upper->rb_node, &cache->rb_root);
1130 			free_backref_node(cache, upper);
1148 			upper = edge->node[UPPER];
1155 			if (list_empty(&lower->upper) &&
1159 			if (!RB_EMPTY_NODE(&upper->rb_node))
1163 			list_for_each_entry(edge, &upper->upper, list[LOWER])
1165 			if (list_empty(&upper->upper))
1166 				list_add(&upper->list, &useless);
1257 				      &new_edge->node[LOWER]->upper);
2578 			if (list_empty(&next->upper))
2581 			edge = list_entry(next->upper.next,
2641 	struct backref_node *upper;  local
2657 	list_for_each_entry(edge, &node->upper, list[LOWER]) {
2660 		upper = edge->node[UPPER];
2661 		root = select_reloc_root(trans, rc, upper, edges);
2664 		if (upper->eb && !upper->locked) {
2666 				ret = btrfs_bin_search(upper->eb, key,
2667 						       upper->level, &slot);
2669 				bytenr = btrfs_node_blockptr(upper->eb, slot);
2673 			drop_node_buffer(upper);
2676 		if (!upper->eb) {
2684 			if (!upper->eb) {
2685 				upper->eb = path->nodes[upper->level];
2686 				path->nodes[upper->level] = NULL;
2688 				BUG_ON(upper->eb != path->nodes[upper->level]);
2691 			upper->locked = 1;
2692 			path->locks[upper->level] = 0;
2694 			slot = path->slots[upper->level];
2697 			ret = btrfs_bin_search(upper->eb, key, upper->level,
2702 		bytenr = btrfs_node_blockptr(upper->eb, slot);
2711 		generation = btrfs_node_ptr_generation(upper->eb, slot);
2722 			ret = btrfs_cow_block(trans, root, eb, upper->eb,
2732 			btrfs_set_node_blockptr(upper->eb, slot,
2734 			btrfs_set_node_ptr_generation(upper->eb, slot,
2736 			btrfs_mark_buffer_dirty(upper->eb);
2740 						upper->eb->start,
2741 						btrfs_header_owner(upper->eb),
2745 			ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2749 		if (!upper->pending)
2750 			drop_node_buffer(upper);
2752 			unlock_node_buffer(upper);
2846 			if (list_empty(&next->upper))
2849 			edge = list_entry(next->upper.next,