> -----Original Message----- > From: NeilBrown [mailto:neilb@xxxxxxx] > Sent: Wednesday, December 14, 2011 5:42 AM > To: Kwolek, Adam > Cc: linux-raid@xxxxxxxxxxxxxxx > Subject: Re: Raid0 expansion problem in md > > On Tue, 13 Dec 2011 15:45:30 +0000 "Kwolek, Adam" > <adam.kwolek@xxxxxxxxx> > wrote: > > > Hi Neil, > > > > On the latest md neil_for-linus branch I've found raid0 migration problem. > > During OLCE in user space everything goes fine, but in kernel process is not > moved forward. > > /older md works fine/ > > > > It is stopped in md in reshape_request() in line (near raid5.c:3957) > > wait_event(conf->wait_for_overlap, > > atomic_read(&conf->reshape_stripes)==0); > > > > I've found that this problem is a side effect of patch: > > md/raid5: abort any pending parity operations when array fails. > > and added line in this patch: > > sh->reconstruct_state = 0; > > > > During OLCE we are going inside because condition > > if (s.failed > conf->max_degraded) with values: > > locked=1 uptodate=5 to_read=0 to_write=0 failed=2 failed_num=4,1 > > > > and sh->reconstruct_state is set to 0 (reconstruct_state_idle) from 6 > > (reconstruct_state_result) When sh->reconstruct_state is not reset raid0 > migration is executed without problem. > > Problem is probably in not executed code for finishing reconstruction > > (around raid5.c:3300) > > > > In our case field s.failed should not reach value 2 but we've got it for > failed_num = 4,1. > > It seems that '1' is failed disk for stripe in old array geometry and 4 is failed > disk for stripe in new array geometry. > > This means that degradation during reshape is counted two times /final > stripe degradation is sum of old and new geometry degradation/. > > When we reading (from old array) and writing (to new geometry) a > > degraded stripe and degradation is on different positions (raid0 OLCE case) > analyse_stripe() gives us false failure information. Possible that we should > have old_failed and new_failed counters to know in what geometry > (old/new) failure occurs. > > > > > > Here is reproduction script: > > > > export IMSM_NO_PLATFORM=1 > > #create container > > mdadm -C /dev/md/imsm0 -amd -e imsm -n 4 /dev/sdb /dev/sdc /dev/sde > > /dev/sdd -R #create array mdadm -C /dev/md/raid0vol_0 -amd -l 0 > > --chunk 64 --size 1048 -n 1 /dev/sdb -R --force #start reshape mdadm > > --grow /dev/md/imsm0 --raid-devices 4 > > > > > > Please let me know your opinion. > > Thanks for the excellent problem report. > > I think it is best fixed by the following patch. > I also need to fixed up the calculate of 'degraded' so it doesn't say '2' in this > case, which is confusing. Then I'll commit the fixes. > > > Thanks, > NeilBrown Yes this helps :) Thanks Neil, BR Adam > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 31670f8..858fdbb > 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -3065,11 +3065,17 @@ static void analyse_stripe(struct stripe_head *sh, > struct stripe_head_state *s) > } > } else if (test_bit(In_sync, &rdev->flags)) > set_bit(R5_Insync, &dev->flags); > - else { > + else if (sh->sector + STRIPE_SECTORS <= rdev- > >recovery_offset) > /* in sync if before recovery_offset */ > - if (sh->sector + STRIPE_SECTORS <= rdev- > >recovery_offset) > - set_bit(R5_Insync, &dev->flags); > - } > + set_bit(R5_Insync, &dev->flags); > + else if (test_bit(R5_UPTODATE, &dev->flags) && > + test_bit(R5_Expanded, &dev->flags)) > + /* If we've reshaped into here, we assume it is > Insync. > + * We will shortly update recovery_offset to make > + * it official. > + */ > + set_bit(R5_Insync, &dev->flags); > + > if (rdev && test_bit(R5_WriteError, &dev->flags)) { > clear_bit(R5_Insync, &dev->flags); > if (!test_bit(Faulty, &rdev->flags)) { -- 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
