Re: Enlarging w/ xfs_growfs: XFS_IOC_FSGROWFSDATA xfsctl failed: Inappropriate ioctl for device

[Nick Bowler <nbowler@draconx.ca>]

On 2018-12-13, Dave Chinner <david@fromorbit.com> wrote:
> On Wed, Dec 12, 2018 at 11:49:36PM -0500, Nick Bowler wrote:
>> To expand on this, for each structure which my RFC patchset feeds up to
>> the native handler, I first checked them by manual inspection and then
>> double checked using the following program; we can compile with both
>> -mx32 and -m64 and check that the output is identical.
>
> So, turn that into an xfstest so that it is always run, diffs the
> output between compat/native depending on which one is used complete
> with guards that break the test when we add a new ioctl. We already
> we have a test that is for explicitly checking that structures on disk
> are the same for 32/64 bit architectures: tests/xfs/122
[...]
> Then we'll have tests that will fail if we ever change an ioctl or
> add a new one and don't add it to the test. That guarantees we won't
> ever forget about this....

OK, I will give it a shot to implement such a test.  A possible issue is
that developers might not have a working x32 build or runtime environment
so the test might not get run a lot.  But hopefully people adding brand
new ioctls don't introduce brand new compat problems; one can dream, right?

Thanks,
  Nick