[PATCH blktests v3 2/2] md: add regression test for "md/md-bitmap: fix writing non bitmap pages"

[Ofir Gal]

On 7/17/24 10:41, Shinichiro Kawasaki wrote:
> Hi Ofir, thank you for this v3 series. The two patches look good to me, except
> one unclear point below.
>
> On Jul 16, 2024 / 14:50, Ofir Gal wrote:
> [...]
>> diff --git a/tests/md/001 b/tests/md/001
>> new file mode 100755
>> index 0000000..e9578e8
>> --- /dev/null
>> +++ b/tests/md/001
>> @@ -0,0 +1,85 @@
>> +#!/bin/bash
>> +# SPDX-License-Identifier: GPL-3.0+
>> +# Copyright (C) 2024 Ofir Gal
>> +#
>> +# The bug is "visible" only when the underlying device of the raid is a network
>> +# block device that utilize MSG_SPLICE_PAGES. nvme-tcp is used as the network device.
>> +#
>> +# Regression test for patch "md/md-bitmap: fix writing non bitmap pages" and
>> +# for patch "nvme-tcp: use sendpages_ok() instead of sendpage_ok()"
>
> The cover letter of the series says that the new test case is the regression
> test for the patch "md/md-bitmap: fix writing non bitmap pages". On the other
> hand, the comment above says that this test case is for the two patches. Which
> is correct? (Or which is more accurate?)
>
> When I ran this test case, it failed on the kernel v6.10, which is expected.
> Then I applied the 1st patch "md/md-bitmap: fix writing non bitmap pages" only
> to the v6.10 kernel, and the test case passed. It passed without the 2nd patch
> "nvme-tcp: use sendpages_ok() instead of sendpage_ok()". So, I'm not sure if
> this test case is the regression test for the 2nd patch.
Sorry for the confusion, either one of the patches solves the issue.

The "md/md-bitmap: fix writing non bitmap pages" patch fix the root
cause issue. md-bitmap sent contiguous pages that it didn't allocate,
that happened to be a page list that consists of non-slub and slub
pages.

The nvme-tcp assumed there won't be a mixed IO of slub and
non-slub in order to turn on MSG_SPLICE_PAGES, "nvme-tcp: use
sendpages_ok() instead of sendpage_ok()" patch address this assumption
by checking each page instead of the first page.

I think it's more accurate to say this regression test for the 1st
patch, we can probably make a separate regression test for the 2nd
patch.

I can change the comment to prevent confusion.