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Commit b3546035 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: allow layout/chunksize to be changed on an active 2-drive raid5. 



2-drive raid5's aren't very interesting.  But if you are converting
a raid1 into a raid5, you will at least temporarily have one.  And
that it a good time to set the layout/chunksize for the new RAID5
if you aren't happy with the defaults.

layout and chunksize don't actually affect the placement of data
on a 2-drive raid5, so we just do some internal book-keeping.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent d562b0c4

drivers/md/md.c

+24 −13
Original line number Diff line number Diff line
@@ -2771,12 +2771,18 @@ layout_store(mddev_t *mddev, const char *buf, size_t len) 
	if (!*buf || (*e && *e != '\n'))

		return -EINVAL;



	if (mddev->pers)

	if (mddev->pers) {

		int err;

		if (mddev->pers->reconfig == NULL)

			return -EBUSY;



		err = mddev->pers->reconfig(mddev, n, -1);

		if (err)

			return err;

	} else {

		mddev->new_layout = n;

		if (mddev->reshape_position == MaxSector)

			mddev->layout = n;

	}

	return len;

}

static struct md_sysfs_entry md_layout =
@@ -2833,19 +2839,24 @@ chunk_size_show(mddev_t *mddev, char *page) 
static ssize_t

chunk_size_store(mddev_t *mddev, const char *buf, size_t len)

{

	/* can only set chunk_size if array is not yet active */

	char *e;

	unsigned long n = simple_strtoul(buf, &e, 10);



	if (!*buf || (*e && *e != '\n'))

		return -EINVAL;



	if (mddev->pers)

	if (mddev->pers) {

		int err;

		if (mddev->pers->reconfig == NULL)

			return -EBUSY;



		err = mddev->pers->reconfig(mddev, -1, n);

		if (err)

			return err;

	} else {

		mddev->new_chunk = n;

		if (mddev->reshape_position == MaxSector)

			mddev->chunk_size = n;

	}

	return len;

}

static struct md_sysfs_entry md_chunk_size =

drivers/md/raid5.c

+42 −0
Original line number Diff line number Diff line
@@ -4913,6 +4913,47 @@ static void *raid5_takeover_raid1(mddev_t *mddev) 
}





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

{

	/* Currently the layout and chunk size can only be changed

	 * for a 2-drive raid array, as in that case no data shuffling

	 * is required.

	 * Later we might validate these and set new_* so a reshape

	 * can complete the change.

	 */

	raid5_conf_t *conf = mddev_to_conf(mddev);



	if (new_layout >= 0 && !algorithm_valid_raid5(new_layout))

		return -EINVAL;

	if (new_chunk > 0) {

		if (new_chunk & (new_chunk-1))

			/* not a power of 2 */

			return -EINVAL;

		if (new_chunk < PAGE_SIZE)

			return -EINVAL;

		if (mddev->array_sectors & ((new_chunk>>9)-1))

			/* not factor of array size */

			return -EINVAL;

	}



	/* They look valid */



	if (mddev->raid_disks != 2)

		return -EINVAL;



	if (new_layout >= 0) {

		conf->algorithm = new_layout;

		mddev->layout = mddev->new_layout = new_layout;

	}

	if (new_chunk > 0) {

		conf->chunk_size = new_chunk;

		mddev->chunk_size = mddev->new_chunk = new_chunk;

	}

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	md_wakeup_thread(mddev->thread);

	return 0;

}



static void *raid5_takeover(mddev_t *mddev)

{

	/* raid5 can take over:
@@ -5023,6 +5064,7 @@ static struct mdk_personality raid5_personality = 
#endif

	.quiesce	= raid5_quiesce,

	.takeover	= raid5_takeover,

	.reconfig	= raid5_reconfig,

};



static struct mdk_personality raid4_personality =