On Fri, 29 Jan 2010 14:54:10 +0000
"Trela, Maciej" <Maciej.Trela@xxxxxxxxx> wrote:
> +static void *raid0_takeover_raid10(mddev_t *mddev)
> +{
> + mdk_rdev_t *rdev;
> +
> + /* Check layout:
> + * assuming that far_copies is 1 and disks number is even
> + * also all mirrors must be already degraded
> + */
> + if ((mddev->layout >> 8) != 1) {
> + printk(KERN_ERR "error: Raid0 cannot takover layout: %x\n", mddev->layout);
> + return ERR_PTR(-EINVAL);
> + }
> + if (mddev->raid_disks & 1) {
> + printk(KERN_ERR "error: Raid0 cannot takover Raid10 with odd disk number.\n");
> + return ERR_PTR(-EINVAL);
> + }
> + if (mddev->degraded != (mddev->raid_disks>>1)) {
> + printk(KERN_ERR "error: All mirrors must be already degraded!\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + /* Set new parameters */
> + mddev->new_level = 0;
> + mddev->raid_disks -= mddev->degraded;
> + mddev->delta_disks = -mddev->degraded;
> + mddev->degraded = 0;
> + /* make sure it will be not marked as dirty */
> + mddev->recovery_cp = MaxSector;
> +
> + list_for_each_entry(rdev, &mddev->disks, same_set) {
> + rdev->raid_disk /= 2;
> + }
You assume here that near_copies is 2, but you never check for that.
Also - and this applies to raid5 and raid10 - the devices may not be all the
same size. raid5 and raid10 will just use the size of the smallest device,
but raid0 won't. For for a seamless conversion, you need to handle the case
that the devices are not the same size. Either disallow that case, or make
use of the extra space.
NeilBrown
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
