Re: [PATCH] generic/038: require fallocate support and test for trim support

[Dave Chinner <david@fromorbit.com>]

On Mon, Dec 15, 2014 at 04:45:10PM -0500, Theodore Ts'o wrote:
> On Tue, Dec 16, 2014 at 07:49:15AM +1100, Dave Chinner wrote:
> > On Mon, Dec 15, 2014 at 11:26:35PM +0100, Dushan Tcholich wrote:
> > > Add tests for allocate support and test if TRIM really works on tested 
> > > partition.
> > > 
> > > Signed-off-by: Dushan Tcholich <dusanc@gmail.com>
> > > 
> > > --- xfstests.orig/tests/generic/038	2014-12-14 15:18:00.000000000 +0100
> > > +++ xfstests/tests/generic/038	2014-12-15 23:21:11.000000000 +0100
> > > @@ -70,6 +70,10 @@
> > >  _supported_os Linux
> > >  _require_scratch
> > >  _require_fstrim
> > > +_require_xfs_io_command "falloc"
> > > +_require_xfs_io_command "truncate"
> > 
> > No need to test for the truncate command as it's supported in all
> > versions of xfs_io people use. falloc, OTOH, isn't supported on oler
> > distros that people still need to run QA on, and hence that check is
> > required....
> 
> I've also been using '_require_xfs_io_command "falloc"' to test
> whether the file system supports fallocate(2).  So for example, in the
> patch that I sent out today, I'm checking not just whether xfs_io
> supports "falloc", but whether the file system under test (at least
> with a specific configuration, such as ext4 in ext3 compatibility
> mode) supports fallocate(2).  Do you consider that a valid thing to
> do?

Yes, that's it's intent. From the 2009 patch that introduced
checks for fallocate support:

+# check that xfs_io, glibc, kernel, and filesystem all (!) support
+# fallocate
+#
+_require_xfs_io_falloc()

i.e. the one function checks the entire stack for fallocate support.
That's not going to change.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com