em1              4085 fs/btrfs/tree-log.c 	struct extent_map *em1, *em2;
em1              4087 fs/btrfs/tree-log.c 	em1 = list_entry(a, struct extent_map, list);
em1              4090 fs/btrfs/tree-log.c 	if (em1->start < em2->start)
em1              4092 fs/btrfs/tree-log.c 	else if (em1->start > em2->start)