Re: [PATCH] shared/005,7: fix making sure debugfs sets negative i_size && add strict check for dd

[Eryu Guan <eguan@redhat.com>]

On Wed, Feb 22, 2017 at 12:56:54PM +0800, Xiao Yang wrote:
> On 2017/02/22 12:20, Eryu Guan wrote:
> > On Mon, Feb 20, 2017 at 01:02:59PM +0800, Xiao Yang wrote:
> > > 1) If the kernel bug has been fixed, stat command fails to get i_size
> > >     and reports "Structure needs cleaning".  So we use debugfs -R "stat"
> > >     instead of stat command to make sure debugfs sets negative i_size.
> > >     These cases have been broken by commit 0e13e40b247a1 ("shared/005,7:
> > >     make sure debugfs sets negative i_size").
> > > 
> > > 2) shared/007 passes unexpectedly on RHEL6.8GA and RHEL6.9Beta
> > >     because of invalid argument. When debugfs fails to set i_size
> > >     to -512, dd with direct flag fails and reports "invalid argument".
> > >     So we can add strict check.
> > But you've already added the check for i_size and _notrun if debugfs
> > failed to set i_size to -512, there's no chance for dd to hit EINVAL.
> > And I think any error dd is hitting is acceptable, as long as test runs
> > (which means i_size was set to -1/-512 successfully). So I don't think
> > we need the check on dd's output. Did I miss anything?
> Hi Eryu
> 
> Thanks for your comments.
> 
> xfs/134 passed unexpectedly on RHEL7.3GA because dd hits ENOSPC.  So I think

Hmm, xfs/134 hits ENOSPC even on 4.9 kernel (where xfs/133 triggers
kernel BUG_ON), so I think the buffer I/O tests are targeded regression
tests and the dio tests are nice-to-have tests.

> all of these cases should fail instead of pass when hitting  unexpected
> error.
> Do you think whether we only check on dd's output of xfs/133,4 or remove
> all? :-)

IMO, what we're going to test is to make sure kernel doesn't hang or
crash when dealing with negative i_size, any error is acceptable as long
as kernel could detect this corruption without crashing or hanging.

Thanks,
Eryu