Re: [xfstests PATCH 0/2] update test_dummy_encryption testing in ext4/053

[Lukas Czerner <lczerner@redhat.com>]

On Wed, May 18, 2022 at 03:01:08PM -0700, Eric Biggers wrote:
> Zorro, can you fix your email configuration?  Your emails have a
> Mail-Followup-To header that excludes you, so replying doesn't work correctly;
> I had to manually fix the recipients list.  If you're using mutt, you need to
> add 'set followup_to = no' to your muttrc.
> 
> On Thu, May 19, 2022 at 02:16:07AM +0800, Zorro Lang wrote:
> > > > 
> > > > And I saw some discussion under this patchset, and no any RVB, so I'm wondering
> > > > if you are still working/changing on it?
> > > > 
> > > 
> > > I might add a check for kernel version >= 5.19 in patch 1.  Otherwise I'm not
> > > planning any more changes.
> > 
> > Actually I don't think the kernel version check (in fstests) is a good method. Better
> > to check a behavior/feature directly likes those "_require_*" functions.
> > 
> > Why ext4/053 need >=5.12 or even >=5.19, what features restrict that? If some
> > features testing might break the garden image (.out file), we can refer to
> > _link_out_file(). Or even split this case to several small cases, make ext4/053
> > only test old stable behaviors. Then use other cases to test new features,
> > and use _require_$feature_you_test for them (avoid the kernel version
> > restriction).
> 
> This has been discussed earlier in this thread as well as on the patch that
> added ext4/053 originally.  ext4/053 has been gated on version >= 5.12 since the
> beginning.  Kernel version checks are certainly bad in general, but ext4/053 is
> a very nit-picky test intended to detect if anything changed, where a change
> does not necessarily mean a bug.  So maybe the kernel version check makes sense
> there.  Lukas, any thoughts about the issues you encountered when running
> ext4/053 on older kernels?

No I haven't encountered any problems, it works fine. I think kernel
version gating in this case it's adequate technical solution for the
problem we have. We want this test to be very nitpicky so that we really
do notice user facing mount behavior change on one hand, while we still
want to have some flexibility.

> 
> If you don't want a >= 5.19 version check for the test_dummy_encryption test
> case as well, then I'd rather treat the kernel patch
> "ext4: only allow test_dummy_encryption when supported" as a bug fix and
> backport it to the LTS kernels.  The patch is fixing the mount option to work
> the way it should have worked originally.  Either that or we just remove the
> test_dummy_encryption test case as Ted suggested.

Both is fine with me, but I would have a preference to treat it as a bug
fix and let the test fail on older kernels without the patch.

-Lukas

> 
> - Eric
>