btrfs_pin_extent
btrfs_pin_extent(trans, node->bytenr, node->num_bytes);
btrfs_pin_extent(trans, node->bytenr, node->num_bytes);
btrfs_pin_extent(trans, head->bytenr, head->num_bytes);
btrfs_pin_extent(trans, ref->bytenr, ref->num_bytes);
btrfs_pin_extent(trans, ins->objectid, ins->offset);
int btrfs_pin_extent(struct btrfs_trans_handle *trans, u64 bytenr, u64 num);