Re: [PATCH 1/1] async_xor: It should add src_offs when dropping destination page

[Xiao Ni <xni@redhat.com>]

On 04/26/2021 02:32 PM, Song Liu wrote:
> On Sun, Apr 25, 2021 at 2:23 AM Xiao Ni <xni@redhat.com> wrote:
>> Now we support sharing one page if PAGE_SIZE is not equal stripe size. To support this,
>> it needs to support calculating xor value with different offsets for each r5dev. One
>> offset array is used to record those offsets.
>>
>> In RMW mode, parity page is used as a source page. It sets ASYNC_TX_XOR_DROP_DST before
>> calculating xor value in ops_run_prexor5. So it needs to add src_list and src_offs at
>> the same time. Now it only needs src_list. So the xor value which is calculated is wrong.
>> It can cause data corruption problem.
>>
>> I can reproduce this problem 100% on a POWER8 machine. The steps are:
>> mdadm -CR /dev/md0 -l5 -n3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --size=3G
>> mkfs.xfs /dev/md0
>> mount /dev/md0 /mnt/test
>> mount: /mnt/test: mount(2) system call failed: Structure needs cleaning.
>>
> Thanks for the fix! Applied to md-next.
>
> A few nits for future patches:
>
>> Fixes: 29bcff787 ("md/raid5: add new xor function to support different page offset")
> Please use "Fixes" with the first 12 characters of the hash: 29bcff787a25.
>
> Also please run checkpatch.pl for the patch. In this one, it complains:
>
> WARNING: Possible unwrapped commit description (prefer a maximum 75
> chars per line)
>
> Thanks,
> Song

Thanks for reminding me. I'll do this next time.

Regards
Xiao