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Commit fc9739c6 authored by NeilBrown's avatar NeilBrown
Browse files

md: add takeover support for converting raid6 back into raid5 



If a raid6 is still in the layout that comes from converting raid5
into a raid6. this will allow us to convert it back again.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent e9d4758f

drivers/md/raid5.c

+35 −0
Original line number Diff line number Diff line
@@ -4912,6 +4912,39 @@ static void *raid5_takeover_raid1(mddev_t *mddev) 
	return setup_conf(mddev);

}



static void *raid5_takeover_raid6(mddev_t *mddev)

{

	int new_layout;



	switch (mddev->layout) {

	case ALGORITHM_LEFT_ASYMMETRIC_6:

		new_layout = ALGORITHM_LEFT_ASYMMETRIC;

		break;

	case ALGORITHM_RIGHT_ASYMMETRIC_6:

		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;

		break;

	case ALGORITHM_LEFT_SYMMETRIC_6:

		new_layout = ALGORITHM_LEFT_SYMMETRIC;

		break;

	case ALGORITHM_RIGHT_SYMMETRIC_6:

		new_layout = ALGORITHM_RIGHT_SYMMETRIC;

		break;

	case ALGORITHM_PARITY_0_6:

		new_layout = ALGORITHM_PARITY_0;

		break;

	case ALGORITHM_PARITY_N:

		new_layout = ALGORITHM_PARITY_N;

		break;

	default:

		return ERR_PTR(-EINVAL);

	}

	mddev->new_level = 5;

	mddev->new_layout = new_layout;

	mddev->delta_disks = -1;

	mddev->raid_disks -= 1;

	return setup_conf(mddev);

}





static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk)

{
@@ -4972,6 +5005,8 @@ static void *raid5_takeover(mddev_t *mddev) 
		mddev->new_level = 5;

		return setup_conf(mddev);

	}

	if (mddev->level == 6)

		return raid5_takeover_raid6(mddev);



	return ERR_PTR(-EINVAL);

}