BTRFS_DELAYED_NODE_IN_LIST
if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {
clear_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags);
if (!test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) {