----- Original Message ----- From: "Oleksandr Shchirskyi" <oleksandr.shchirskyi@xxxxxxxxxxxxxxx> To: "Nigel Croxon" <ncroxon@xxxxxxxxxx> Cc: linux-raid@xxxxxxxxxxxxxxx, "Mariusz Tkaczyk" <mariusz.tkaczyk@xxxxxxxxxxxxxxx>, "Jes Sorensen" <jes@xxxxxxxxxxxxxxxxxx> Sent: Monday, March 22, 2021 1:41:17 PM Subject: Re: [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup file dmesg output for my test scenario with you patch applied: [534716.791252] md126: detected capacity change from 0 to 41943040 [534716.797684] md: md126 still in use. [534716.803334] md: md126 stopped. [534716.829098] md: md127 stopped. [534718.036483] md126: detected capacity change from 20971520 to 0 [534741.743609] md/raid:md126: device nvme0n1 operational as raid disk 0 [534741.762739] md/raid:md126: raid level 4 active with 1 out of 2 devices, algorithm 5 [534741.822765] md: reshape of RAID array md126 [534747.144197] md: md126: reshape interrupted. [534747.149098] md: reshape of RAID array md126 [534747.566093] md: md126: reshape interrupted. [534747.570979] md: reshape of RAID array md126 [534793.916521] md: md126: reshape done. and w/o: [534907.642262] md126: detected capacity change from 0 to 20971520 [534907.648697] md: md126 still in use. [534907.654340] md: md126 stopped. [534907.679414] md: md127 stopped. [534911.985080] md126: detected capacity change from 20971520 to 0 [534922.920777] md/raid:md126: device nvme0n1 operational as raid disk 0 [534922.940442] md/raid:md126: raid level 4 active with 1 out of 2 devices, algorithm 5 [534922.995454] md: reshape of RAID array md126 [534975.643237] md: md126: reshape done. [534975.669424] md126: detected capacity change from 41943040 to 20971520 Not sure what is causing errors you see. btw, I'm working on md-next 5.11.0 kernel from 02/24 On 3/22/2021 6:16 PM, Nigel Croxon wrote: > > > ----- Original Message ----- > From: "Oleksandr Shchirskyi" <oleksandr.shchirskyi@xxxxxxxxxxxxxxx> > To: "Nigel Croxon" <ncroxon@xxxxxxxxxx>, linux-raid@xxxxxxxxxxxxxxx > Cc: "Mariusz Tkaczyk" <mariusz.tkaczyk@xxxxxxxxxxxxxxx>, "Jes Sorensen" <jes@xxxxxxxxxxxxxxxxxx> > Sent: Monday, March 22, 2021 12:21:11 PM > Subject: Re: [PATCH] mdadm: fix reshape from RAID5 to RAID6 with backup file > > 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@xxxxxxxxxxxxxxx> >> To: "Jes Sorensen" <jes@xxxxxxxxxxxxxxxxxx>, "Nigel Croxon" <ncroxon@redhat= >> .com>, linux-raid@xxxxxxxxxxxxxxx, xni@xxxxxxxxxx >> 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 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
