make_thread_read_only
vdo_prepare_completion(completion, make_thread_read_only,
make_thread_read_only, thread_id,
vdo_prepare_completion(completion, make_thread_read_only,
make_thread_read_only, thread_id, NULL);
make_thread_read_only(¬ifier->completion);
vdo_launch_completion_callback(¬ifier->completion, make_thread_read_only, 0);