Re: Backporting of series xfs/iomap: fix data corruption due to stale cached iomap

[Frederick Lawler <fred@cloudflare.com>]

Hi Amir and Luis

On 7/20/23 1:30 PM, Luis Chamberlain wrote:
> On Thu, Jul 20, 2023 at 09:45:14AM +0300, Amir Goldstein wrote:
>> On Wed, Jul 19, 2023 at 11:37 PM Ignat Korchagin <ignat@cloudflare.com> wrote:
>>>
>>> Circling back on this. So far it seems that the patchset in question
>>> does fix the issues of rocksdb corruption as we haven't seen them for
>>> some time on our test group. We're happy to dedicate some efforts now
>>> to get them officially backported to 6.1 according to the process. We
>>> did try basic things with kdevops and would like to learn more. Fred
>>> (cc-ed here) is happy to drive the effort and be the primary contact
>>> on this. Could you, please, guide us/him on the process?
>>>
>>
>> Hi Fred,
>>
>> I'd love to help you get started with kdevops and xfs testing.
>> However, I am going on vacation tomorrow for three weeks,
>> so I'll just drop a few pointers and let the others help you out.
>>
>> Luis (@mcgrof) is your best point of contact for kdevops.
> 
> I'm happy to help.
> 
>> Chandan should be able to help you with xfs backporting questions.
>>
>> Better yet, use the discord channel:
>>    https://bit.ly/linux-kdevops-chat
>>
>> Someone is almost always available to answer questions there.
> 
> Indeed and also on irc.oftc.net on #kdevops too if you prefer IRC.
> But discord seems to be more happening for kdevops these days.
> 
>> TESTING:
>> --------------
>> The most challenging part of running fstests with kdevops is
>> establishing the baseline (which tests pass in current 6.1.y per xfs config),
>> but the baseline for that has already been established and committed
>> in kdevops repo.
>>
>> There is a little quirk, that the baseline is associated only with exact
>> kernel version, hence commits like:
>> * c4e3de1 bootlinux: add expunge link for v6.1.39
> 
> Indeed so our latest baseline is in
> 
> workflows/fstests/expunges/6.1.39/xfs/unassigned/
> 
>> Make sure that you test your patches against one of those tags
>> or add new symlinks to other tags.
>> Start by running a sanity test without your patches, because different
>> running environments and kdevops configs may disagree on the baseline.
> 
> You want to first run at least one loop to confirm your setup is fine
> and that you don't find any other failures other than the ones above.
> 
>> You can use kdevops to either run local VMs with libvirt or launch
>> cloud VMs with terraform - you need to configure this and more
>> during the 'make menuconfig' step.
>> Attaching my kdevops config (for libvirt guests) as a reference.
> 
> Please read:
> 
> https://github.com/linux-kdevops/kdevops
> https://github.com/linux-kdevops/kdevops/blob/master/docs/requirements.md
> https://github.com/linux-kdevops/kdevops/blob/master/docs/kdevops-first-run.md
> https://github.com/linux-kdevops/kdevops/blob/master/docs/kdevops-mirror.md
> 
> And the video demonstrations. Then I'm happy to schedule some time to
> cover anything the docs didn't cover, in particular to help you test new
> patches you wish to backport for a stable kernel and the testing
> criteria for that.
> 
>    Luis

This is all fantastic! I just joined the discord and will likely begin 
work on this tomorrow. I've already setup kdevops and ran through some 
selftests earlier this week. I still need to watch the video however. 
I'll reach out in Discord after I give a crack at what's presented so far.

Fred