Re: [PATCH 3/3] btrfs: test mount fails on physical device with configured dm volume

From: Anand Jain <anand.jain@oracle.com>
To: Filipe Manana <fdmanana@kernel.org>
Cc: fstests@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 3/3] btrfs: test mount fails on physical device with configured dm volume
Date: Fri, 8 Mar 2024 19:05:11 +0530	[thread overview]
Message-ID: <290e74fe-d199-4c8c-bf02-f7003232dad9@oracle.com> (raw)
In-Reply-To: <CAL3q7H4HV-UBd9hEKB1+isH2H4TThsx0DnvfYxsY+=BB64PqqA@mail.gmail.com>

On 3/8/24 18:00, Filipe Manana wrote:
> On Thu, Mar 7, 2024 at 4:46 PM Anand Jain <anand.jain@oracle.com> wrote:
>>
>>
>>> I'm also not convinced that we need this test, because the bug could
>>> be reliably reproduced by running all existing tests or just a subset
>>> of the tests as I reported there.
>>
>> This test case was motivated by btrfs/159; and recent report;
>> yep, most of the lines here are taken from btrfs/159.
> 
> Ok, so it's motivated by what I reported, triggered by btrfs/159 but
> only when other tests are run before it.
> 
>> However, I wanted a test case in the tempfsid group which
>> exercises multi-node-same-physical;
> 
> Sure. It's just that we could trigger the issue simply by running all
> existing tests, or just a subset as I reported before [1].
> It was fully deterministic and David could reproduce it after the report too.
> 
> What surprises me is that no one noticed this before and at some stage
> the faulty patch was about to be sent to Linus.
> 
>>
>> If there are no objections, I am going to add the tempfsid group to
>> btrfs/159 for now.
> 
> That is confusing, please don't.
> btrfs/159 doesn't test tempfsid, it existed for many years before the
> tempfsid feature (introduced in the 6.7 kernel),
> it just happens that it triggers the issue if other fstests are run before it.
> 
> That would also be pointless because running btrfs/159 alone doesn't
> trigger the bug, so running "./check -g tempfsid" wouldn't cause 159
> to fail.
> 
> Between that and a new test case that is somewhat redundant, I'd
> rather have the new test case with proper documentation/comments.
> 

I have converted this test case into a generic one. Now, XFS, ext4,
and Btrfs (after a patch) match the golden output. I'll be sending
the btrfs kernel patch along with it.

Thanks, Anand

> Thanks.
> 
> [1] https://lore.kernel.org/linux-btrfs/CAL3q7H5wx5rKmSzGWP7mRqaSfAY88g=35N4OBrbJB61rK0mt2w@mail.gmail.com/
> 
>>
>> Thanks, Anand