From: Nigel Croxon <ncroxon@redhat.com>
To: Oleksandr Shchirskyi <oleksandr.shchirskyi@linux.intel.com>
Cc: linux-raid@vger.kernel.org, "Tkaczyk,
Mariusz" <mariusz.tkaczyk@linux.intel.com>,
Jes Sorensen <jes@trained-monkey.org>
Subject: Re: [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup file
Date: Mon, 22 Mar 2021 12:47:05 -0400 [thread overview]
Message-ID: <2D9512A3-9D7B-4044-B4E2-5733A05CA9FE@redhat.com> (raw)
In-Reply-To: <08b71ea7-bdd3-722d-d18f-aa065b8756c0@linux.intel.com>
Jes,
Can we have a revert until the issue has been resolved for all?
Thanks Oleskandr for the diagnose.
-Nigel
> On Mar 22, 2021, at 12:21 PM, Oleksandr Shchirskyi <oleksandr.shchirskyi@linux.intel.com> wrote:
>
> Hello Nigel,
>
> I have collected more info regarding this issue.
> I can confirm what Mariusz said, it's a regression caused by patch 4ae96c802203
> The reason for failure during the reshape, is that in this patch sync_max value is set to max, but the function wait_for_reshape_imsm, used in some reshape scenarios, relies on this parameter, and doesn't expect, that value can be max. This leads to reshaping fail.
> Here's an example of a debug log from this method, when the issue is hit:
>
> mdadm: wait_for_reshape_imsm: wrong next position to set 4096 (2048)
> mdadm: imsm_manage_reshape: wait_for_reshape_imsm returned error!
>
> With this patch reverted, the issue is not observed. See my logs below:
>
> # 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 -D /dev/md/volume /dev/md/volume:
> Container : /dev/md/imsm0, member 0
> Raid Level : raid0
> Array Size : 10485760 (10.00 GiB 10.74 GB)
> Raid Devices : 1
> Total Devices : 1
> State : clean
> ...
> # mdadm -G /dev/md/imsm0 -n2
> # mdadm -D /dev/md/volume
> /dev/md/volume:
> Container : /dev/md/imsm0, member 0
> Raid Level : raid4
> Array Size : 10485760 (10.00 GiB 10.74 GB)
> Used Dev Size : 10485760 (10.00 GiB 10.74 GB)
> Raid Devices : 3
> Total Devices : 2
> State : clean, degraded
> ...
> # git revert 4ae96c802203ec3cfbb089240c56d61f7f4661b3
> Auto-merging Grow.c
> [master 1166854] Revert "mdadm: fix reshape from RAID5 to RAID6 with backup file"
> 1 file changed, 2 insertions(+), 5 deletions(-)
> # mdadm -Ss; wipefs -a /dev/nvme[0-3]n1
> # 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
> # mdadm -D /dev/md/volume
> /dev/md/volume:
> Container : /dev/md/imsm0, member 0
> Raid Level : raid0
> Array Size : 20971520 (20.00 GiB 21.47 GB)
> Raid Devices : 2
> Total Devices : 2
>
> State : clean
> ...
> #
>
> On 3/16/2021 4:59 PM, Nigel Croxon wrote:
>> ----- Original Message -----
>> From: "Mariusz Tkaczyk" <mariusz.tkaczyk@linux.intel.com>
>> To: "Jes Sorensen" <jes@trained-monkey.org>, "Nigel Croxon" <ncroxon@redhat=
>> .com>, linux-raid@vger.kernel.org, xni@redhat.com
>> Sent: Tuesday, March 16, 2021 10:54:22 AM
>> Subject: Re: [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup fil=
>> e
>> Hello Nigel,
>> Blame told us, that yours patch introduce regression in following
>> scenario:
>> #mdadm -CR imsm0 -e imsm -n4 /dev/nvme[0125]n1
>> #mdadm -CR volume -l0 --chunk 64 --raid-devices=3D1 /dev/nvme0n1 --force
>> #mdadm -G /dev/md/imsm0 -n2
>> At the end of reshape, level doesn't back to RAID0.
>> Could you look into it?
>> Let me know, if you need support.
>> Thanks,
>> Mariusz
>> I=E2=80=99m trying your situation without my patch (its reverted) and I=E2=
>> =80=99m not seeing success.
>> See the dmesg log.
>> [root@fedora33 mdadmupstream]# mdadm -CR volume -l0 --chunk 64 --raid-devic=
>> es=3D1 /dev/nvme0n1 --force
>> mdadm: /dev/nvme0n1 appears to be part of a raid array:
>> level=3Dcontainer devices=3D0 ctime=3DWed Dec 31 19:00:00 1969
>> mdadm: Creating array inside imsm container md127
>> mdadm: array /dev/md/volume started.
>> [root@fedora33 mdadmupstream]# cat /proc/mdstat=20
>> Personalities : [raid6] [raid5] [raid4] [raid0]=20
>> md126 : active raid0 nvme0n1[0]
>> 500102144 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
>> unused devices: <none>
>> [root@fedora33 mdadmupstream]# mdadm -G /dev/md/imsm0 -n2
>> [root@fedora33 mdadmupstream]# cat /proc/mdstat=20
>> Personalities : [raid6] [raid5] [raid4] [raid0]=20
>> md126 : active raid4 nvme3n1[2] nvme0n1[0]
>> 500102144 blocks super external:-md127/0 level 4, 64k chunk, algorithm=
>> 5 [2/1] [U_]
>> md127 : inactive nvme3n1[3](S) nvme2n1[2](S) nvme1n1[1](S) nvme0n1[0](S)
>> 4420 blocks super external:imsm
>> unused devices: <none>
>> dmesg says:
>> [Mar16 11:46] md/raid:md126: device nvme0n1 operational as raid disk 0
>> [ +0.011147] md/raid:md126: raid level 4 active with 1 out of 2 devices, a=
>> lgorithm 5
>> [ +0.044605] md/raid0:md126: raid5 must have missing parity disk!
>> [ +0.000002] md: md126: raid0 would not accept array
>> -Nigel
>
> --
> Regards,
> Oleksandr Shchirskyi
>
next prev parent reply other threads:[~2021-03-22 16:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <764426808.38181143.1615910368475.JavaMail.zimbra () redhat ! com>
2021-03-22 16:21 ` [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup file Oleksandr Shchirskyi
2021-03-22 16:47 ` Nigel Croxon [this message]
2021-03-22 17:16 ` Nigel Croxon
2021-03-22 17:41 ` Oleksandr Shchirskyi
2021-03-23 16:36 ` Nigel Croxon
2021-03-23 20:58 ` Oleksandr Shchirskyi
2021-03-26 11:59 ` Nigel Croxon
2021-04-01 20:49 ` Jes Sorensen
2021-04-02 9:40 ` Oleksandr Shchirskyi
2021-04-06 18:31 ` Jes Sorensen
2021-01-20 20:05 Nigel Croxon
2021-02-16 14:28 ` Nigel Croxon
2021-02-26 22:06 ` Jes Sorensen
2021-03-16 14:54 ` Tkaczyk, Mariusz
2021-03-16 15:21 ` Nigel Croxon
2021-03-16 15:51 ` Nigel Croxon
2021-03-16 15:59 ` Nigel Croxon
2021-03-17 8:34 ` Tkaczyk, Mariusz
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