From: NeilBrown Recent patch for raid6 reshape had a change missing that showed up in subsequent review. Many places in the raid5 code used "conf->raid_disks-1" to mean "number of data disks". With raid6 that had to be changed to "conf->raid_disk - conf->max_degraded" or similar. One place was missed. This bug means that if a raid6 reshape were aborted in the middle the recorded position would be wrong. On restart it would either fail (as the position wasn't on an appropriate boundary) or would leave a section of the array unreshaped, causing data corruption. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- drivers/md/raid5.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN drivers/md/raid5.c~md-fix-for-raid6-reshape drivers/md/raid5.c --- a/drivers/md/raid5.c~md-fix-for-raid6-reshape +++ a/drivers/md/raid5.c @@ -3071,7 +3071,7 @@ static sector_t reshape_request(mddev_t release_stripe(sh); } spin_lock_irq(&conf->device_lock); - conf->expand_progress = (sector_nr + i)*(conf->raid_disks-1); + conf->expand_progress = (sector_nr + i) * new_data_disks); spin_unlock_irq(&conf->device_lock); /* Ok, those stripe are ready. We can start scheduling * reads on the source stripes. _