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Date:   Wed, 20 Jul 2022 07:42:25 -0400
From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Zorro Lang <zlang@redhat.com>
Cc:     Jeremy Bongio <bongiojp@gmail.com>, linux-ext4@vger.kernel.org,
        fstests@vger.kernel.org, "Darrick J . Wong" <djwong@kernel.org>
Subject: Re: [PATCH v5] ext4/056: add a check to make sure ext4 uuid ioctls
 get/set during fsstress.
Message-ID: <YtfqIVEi7g4fFpqU@mit.edu>
References: <20220720000256.239531-1-bongiojp@gmail.com>
 <20220720100949.dttc5qbmy4qziz65@zlang-mailbox>
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On Wed, Jul 20, 2022 at 06:09:49PM +0800, Zorro Lang wrote:
> On Tue, Jul 19, 2022 at 05:02:56PM -0700, Jeremy Bongio wrote:
> > +# Override the default cleanup function.
> > +_cleanup()
> > +{
> > +        cd /
> > +        rm -r -f $tmp.*
> > +        kill -9 $fsstress_pid 2>/dev/null;
> > +        wait $fsstress_pid > /dev/null 2>&1
> 
> I think "wait" is enough. With this change, it's good to me.

The kill -9 is needed, because otherwise the test will run for a
**very** long time.  The reason for it is because of the -n 999999 in
fstress_args:

> > +# Begin fsstress while modifying UUID
> > +fsstress_args=$(_scale_fsstress_args -d $SCRATCH_MNT -p 15 -n 999999)
> > +$FSSTRESS_PROG $fsstress_args > /dev/null 2>&1 &
> > +fsstress_pid=$!

We could adjust the number of loops to a more reasonable number, but
then test becomes less reliable, since depending on the storage device
(e.g., cheap USB thumb drive found in the checkout counter at a
convenience store, vs. a high-end NVMe SSD) and the overall speed of
the system, a different number of loops will be needed.

Given that we're *only* using the fsstress as an antogonist while we
are changing the UUID of the file system 20 times, killing the
fsstress once we're done with the UUID runs is sufficient, I would
argue.

Also, Jeremy, it looks like you haven't updated your xfstests-dev
repository in a few weeks.  Since you started this project, ext4/056
has been assigned, and there has been some new helper programs added
which caused patch conflicts in src/Makefile and in .gitignore.  They
were pretty trivial to fix up the patch conflicts (which I've done in
my xfstests-dev tree), but it's best practice to rebase on top of
origin/for-next and re-test just to make sure there haven't been some
major change in the fstests common scripts that might catch your test
out.

Also, feel free to add my:

Reviewed-by: Theodore Ts'o <tytso@mit.edu>

Cheers,

						- Ted