Add check to determine if a device needs full resync or if partial resync will do

RAID 5 was assuming that if a device was not In_sync, it must undergo a full
resync.  We add a check to see if 'saved_raid_disk' is the same as 'raid_disk'.
If it is, we can safely skip the full resync and rely on the bitmap for
partial recovery instead.  This is the legitimate purpose of 'saved_raid_disk',
from md.h:
int saved_raid_disk;            /* role that device used to have in the
                                 * array and could again if we did a partial
                                 * resync from the bitmap
                                 */

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Jonathan Brassow 2011-06-08 18:00:28 -05:00 коммит произвёл NeilBrown
Родитель 9c81075f43
Коммит d6b212f4b1
1 изменённых файлов: 1 добавлений и 1 удалений

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@ -4858,7 +4858,7 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
printk(KERN_INFO "md/raid:%s: device %s operational as raid"
" disk %d\n",
mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
} else
} else if (rdev->saved_raid_disk != raid_disk)
/* Cannot rely on bitmap to complete recovery */
conf->fullsync = 1;
}