Re: [PATCH] generic/071: require falloc -k

[Eryu Guan <eguan@redhat.com>]

On Tue, Jul 19, 2016 at 10:30:47AM +0200, Christoph Hellwig wrote:
> On Mon, Jul 18, 2016 at 11:49:57PM -0700, Eric Sandeen wrote:
> > Some tests actually do run xfs_io on a real file, but we probably
> > don't want to go that way.
> > 
> > The test for finding it in help output seems way too specific,
> > 
> > _require_xfs_io_command "pwrite" "-Z"
> > 
> > fails as well because it doesn't hit the specific format in
> > the grep.
> > 
> > What if we loosen up the test; is this too loose? (look for param
> > preceded by whitespace or square bracket)
> 
> Seems like it's not loose enough as it still tries to run the test
> on NFS.

For this NFSv4.2 case, I think we have to actually run "falloc -k" to
check whether the underlying fs supports (FALLOC_FL_KEEP_SIZE) or not.

Current check in _require_xfs_io_command only checks whether xfs_io
knows the given option, not the underlying fs. And in this NFSv4.2 case,
NFSv4.2 supports fallocate(2), and xfs_io falloc command knows "-k"
option, so test runs on NFS.

Thanks,
Eryu