static void raise_barrier(struct r1conf *conf)
{
	spin_lock_irq(&conf->resync_lock);

	pr_info("%s: raise_barrier(1): conf->barrier=%d conf->nr_waiting=%d conf->nr_pending=%d conf->pending_count=%d\n", mdname(conf->mddev), conf->barrier, conf->nr_waiting, conf->nr_pending, conf->pending_count);

	/* Wait until no block IO is waiting */
	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
			    conf->resync_lock);

	/* block any new IO from starting */
	conf->barrier++;

	pr_info("%s: raise_barrier(2): conf->barrier=%d conf->nr_waiting=%d conf->nr_pending=%d conf->pending_count=%d\n", mdname(conf->mddev), conf->barrier, conf->nr_waiting, conf->nr_pending, conf->pending_count);

	/* Now wait for all pending IO to complete */
	wait_event_lock_irq(conf->wait_barrier,
			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
			    conf->resync_lock);

	pr_info("%s: raise_barrier(3): conf->barrier=%d conf->nr_waiting=%d conf->nr_pending=%d conf->pending_count=%d\n", mdname(conf->mddev), conf->barrier, conf->nr_waiting, conf->nr_pending, conf->pending_count);

	spin_unlock_irq(&conf->resync_lock);
}

static void wait_barrier(struct r1conf *conf)
{
	int waited = 0;
	
	spin_lock_irq(&conf->resync_lock);
	if (conf->barrier) {
		conf->nr_waiting++;

		waited = 1;
		pr_info("%s: wait_barrier(PID=%d,1) conf->barrier=%d conf->nr_waiting=%d conf->nr_pending=%d conf->pending_count=%d\n", mdname(conf->mddev), current->pid, 
			    conf->barrier, conf->nr_waiting, conf->nr_pending, conf->pending_count);
		if (conf->nr_pending && current->bio_list && !bio_list_empty(current->bio_list))
			dump_stack();

		/* Wait for the barrier to drop.
		 * However if there are already pending
		 * requests (preventing the barrier from
		 * rising completely), and the
		 * pre-process bio queue isn't empty,
		 * then don't wait, as we need to empty
		 * that queue to get the nr_pending
		 * count down.
		 */
		wait_event_lock_irq(conf->wait_barrier,
				    !conf->barrier ||
				    (conf->nr_pending &&
				     current->bio_list &&
				     !bio_list_empty(current->bio_list)),
				    conf->resync_lock);
		conf->nr_waiting--;
	}
	conf->nr_pending++;

	if (waited)
		pr_info("%s: wait_barrier(PID=%d,2) conf->barrier=%d conf->nr_waiting=%d conf->nr_pending=%d conf->pending_count=%d\n", mdname(conf->mddev), current->pid, 
			    conf->barrier, conf->nr_waiting, conf->nr_pending, conf->pending_count);

	spin_unlock_irq(&conf->resync_lock);
}