Commit 04788507 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon
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dm raid1: add framework to hold bios during suspend 



Add framework to delay bios until a suspend and then resubmit them with
either DM_ENDIO_REQUEUE (if the suspend was noflush) or complete them
with -EIO.  I/O barrier support will use this.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: default avatarTakahiro Yasui <tyasui@redhat.com>
Tested-by: default avatarTakahiro Yasui <tyasui@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 64b30c46

drivers/md/dm-raid1.c

+41 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ struct mirror_set { 
	struct bio_list reads;

	struct bio_list writes;

	struct bio_list failures;

	struct bio_list holds;	/* bios are waiting until suspend */



	struct dm_region_hash *rh;

	struct dm_kcopyd_client *kcopyd_client;
@@ -450,6 +451,27 @@ static void map_region(struct dm_io_region *io, struct mirror *m, 
	io->count = bio->bi_size >> 9;

}



static void hold_bio(struct mirror_set *ms, struct bio *bio)

{

	/*

	 * If device is suspended, complete the bio.

	 */

	if (atomic_read(&ms->suspend)) {

		if (dm_noflush_suspending(ms->ti))

			bio_endio(bio, DM_ENDIO_REQUEUE);

		else

			bio_endio(bio, -EIO);

		return;

	}



	/*

	 * Hold bio until the suspend is complete.

	 */

	spin_lock_irq(&ms->lock);

	bio_list_add(&ms->holds, bio);

	spin_unlock_irq(&ms->lock);

}



/*-----------------------------------------------------------------

 * Reads

 *---------------------------------------------------------------*/
@@ -1225,6 +1247,9 @@ static void mirror_presuspend(struct dm_target *ti) 
	struct mirror_set *ms = (struct mirror_set *) ti->private;

	struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);



	struct bio_list holds;

	struct bio *bio;



	atomic_set(&ms->suspend, 1);



	/*
@@ -1247,6 +1272,22 @@ static void mirror_presuspend(struct dm_target *ti) 
	 * we know that all of our I/O has been pushed.

	 */

	flush_workqueue(ms->kmirrord_wq);



	/*

	 * Now set ms->suspend is set and the workqueue flushed, no more

	 * entries can be added to ms->hold list, so process it.

	 *

	 * Bios can still arrive concurrently with or after this

	 * presuspend function, but they cannot join the hold list

	 * because ms->suspend is set.

	 */

	spin_lock_irq(&ms->lock);

	holds = ms->holds;

	bio_list_init(&ms->holds);

	spin_unlock_irq(&ms->lock);



	while ((bio = bio_list_pop(&holds)))

		hold_bio(ms, bio);

}



static void mirror_postsuspend(struct dm_target *ti)