Re: [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup file

[Oleksandr Shchirskyi <oleksandr.shchirskyi@linux.intel.com>]

On 4/1/2021 10:49 PM, Jes Sorensen wrote:
> On 3/26/21 7:59 AM, Nigel Croxon wrote:> ----- Original Message ----->
> From: "Oleksandr Shchirskyi" <oleksandr.shchirskyi@linux.intel.com>> To:
> "Nigel Croxon" <ncroxon@redhat.com>
>> Cc: linux-raid@vger.kernel.org, "Mariusz Tkaczyk" <mariusz.tkaczyk@linux.intel.com>, "Jes Sorensen" <jes@trained-monkey.org>
>> Sent: Tuesday, March 23, 2021 4:58:27 PM
>> Subject: Re: [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup file
>>
>> On 3/23/2021 5:36 PM, Nigel Croxon wrote:
>>> Oleksandr,
>>> Can you post your dmesg output when running the commands?
>>>
>>> I've back down from 5.11 to 5.8 and I still see:
>>> [  +0.042694] md/raid0:md126: raid5 must have missing parity disk!
>>> [  +0.000001] md: md126: raid0 would not accept array
>>>
>>> Thanks, Nigel
>>
>> Hello Nigel,
>>
>> I've switched to 4.18.0-240.el8.x86_64 kernel (I have RHEL8.3) and I still
>> have the same results, issue is still easily reproducible when patch
>> 4ae96c8 is applied.
>>
>> Cropped test logs with and w/o your patch:
>>
>> # git log -n1 --oneline
>> f94df5c (HEAD -> master, origin/master, origin/HEAD) imsm: support for
>> third Sata controller
>> # make clean; make; make install-systemd; make install
>> # mdadm -CR imsm0 -e imsm -n4 /dev/nvme[0-3]n1 && mdadm -CR volume -l0
>> --chunk 64 --size=10G --raid-devices=1 /dev/nvme0n1 --force
>> # mdadm -G /dev/md/imsm0 -n2
>> # dmesg -c
>> [  393.530389] md126: detected capacity change from 0 to 10737418240
>> [  407.139318] md/raid:md126: device nvme0n1 operational as raid disk 0
>> [  407.153920] md/raid:md126: raid level 4 active with 1 out of 2 devices,
>> algorithm 5
>> [  407.246037] md: reshape of RAID array md126
>> [  407.357940] md: md126: reshape interrupted.
>> [  407.388144] md: reshape of RAID array md126
>> [  407.398737] md: md126: reshape interrupted.
>> [  407.403486] md: reshape of RAID array md126
>> [  459.414250] md: md126: reshape done.
>> # cat /proc/mdstat
>> Personalities : [raid0] [raid6] [raid5] [raid4]
>> md126 : active raid4 nvme3n1[2] nvme0n1[0]
>>         10485760 blocks super external:/md127/0 level 4, 64k chunk,
>> algorithm 0 [3/2] [UU_]
>>
>> md127 : inactive nvme3n1[3](S) nvme2n1[2](S) nvme1n1[1](S) nvme0n1[0](S)
>>         4420 blocks super external:imsm
>>
>> unused devices: <none>
>>
>> # mdadm -Ss; wipefs -a /dev/nvme[0-3]n1
>> # dmesg -C
>> # git revert 4ae96c802203ec3cfbb089240c56d61f7f4661b3
>> # make clean; make; make install-systemd; make install
>> # mdadm -CR imsm0 -e imsm -n4 /dev/nvme[0-3]n1 && mdadm -CR volume -l0
>> --chunk 64 --size=10G --raid-devices=1 /dev/nvme0n1 --force
>> # mdadm -G /dev/md/imsm0 -n2
>> # dmesg -c
>> [  623.772039] md126: detected capacity change from 0 to 10737418240
>> [  644.823245] md/raid:md126: device nvme0n1 operational as raid disk 0
>> [  644.838542] md/raid:md126: raid level 4 active with 1 out of 2 devices,
>> algorithm 5
>> [  644.928672] md: reshape of RAID array md126
>> [  697.405351] md: md126: reshape done.
>> [  697.409659] md126: detected capacity change from 10737418240 to 21474836480
>> # cat /proc/mdstat
>> Personalities : [raid0] [raid6] [raid5] [raid4]
>> md126 : active raid0 nvme3n1[2] nvme0n1[0]
>>         20971520 blocks super external:/md127/0 64k chunks
>>
>> md127 : inactive nvme3n1[3](S) nvme2n1[2](S) nvme1n1[1](S) nvme0n1[0](S)
>>         4420 blocks super external:imsm
>>
>>
>> Do you need more detailed logs? My system/drives configuration details?
>>
>> Regards,
>> Oleksandr Shchirskyi
>>
>>
>>
>>
>>  From f0c80c8e90b2ce113b6e22f919659430d3d20efa Mon Sep 17 00:00:00 2001
>> From: Nigel Croxon <ncroxon@redhat.com>
>> Date: Fri, 26 Mar 2021 07:56:10 -0400
>> Subject: [PATCH] mdadm: fix growing containers
>>
>> This fixes growing containers which was broken with
>> commit 4ae96c802203ec3c (mdadm: fix reshape from RAID5 to RAID6 with
>> backup file)
>>
>> The issue being that containers use the function
>> wait_for_reshape_isms and expect a number value and not a
>> string value of "max".  The change is to test for external
>> before setting the correct value.
>>
>> Signed-off-by: Nigel Croxon <ncroxon@redhat.com>
> 
> I was about to revert the problematic patch. Oleksandr, can you confirm
> if it resolves the issues you were seeing?
> 
> Thanks,
> Jes
> 

Hi Jes,

Yes, I can confirm that the issue has been resolved with this patch.

Thanks,
Oleksandr Shchirskyi