Re: [PATCH] generic/70: Use scratch device instead of test.

[Dave Chinner <david@fromorbit.com>]

On Thu, Aug 19, 2021 at 05:56:31PM +0300, Nikolay Borisov wrote:
> 
> 
> On 19.08.21 г. 18:00, Zorro Lang wrote:
> > On Thu, Aug 19, 2021 at 04:13:55PM +0300, Nikolay Borisov wrote:
> >> At the end of the test the fsstress work dir is deleted, this suggests
> >> the test really requires a scratch device and not a test device. Change
> >> it accordingly.
> >>
> >> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> >> ---
> > 
> > Hmm... is there any more specific reasons to explain why have to change this
> > TEST_DIR to SCRATCH_MNT? For example, this test hit ENOSPC in TEST_DIR, or
> > it takes too much time to remove $TEST_DIR/fsstress in _cleanup, or use
> > SCRATCH_DEV can cover more things, and so on. I think more specific reason
> > can help to push this patch be merged. After all there's not a rule says
> > if a case don't need to keep its work dir, then must use SCRATCH_DEV. Except
> > the maintainer is more inclined to accept that :)
> 
> None of the reasons above, I just thought that stuff in $TEST_DEV lives
> there so that it can simulate an 'aging' system. In this case this
> doesn't seem to be the reason for it as we delete everything.

That's most certainly aging the filesystem. Just because the test
deletes everything it wrote doesn't mean that the filesystem is
unchanged after the test runs. e.g. log structured or COW filesytems
can have very different structures at the end of the test, even
though the current view of the filesystem appears unchanged...

IOWs, tests that don't require a specific filesystem configuration
should be run on the test device, not the scratch device...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com