Re: [PATCH v6 3/3] xfs: add support for FALLOC_FL_WRITE_ZEROES

On Thu, Jun 18, 2026 at 02:00:16AM -0700, Christoph Hellwig wrote:
> On Wed, Jun 17, 2026 at 11:44:47AM +0200, Pankaj Raghav (Samsung) wrote:
> > > Maybe we also want xfstests that try unaligned FALLOC_FL_WRITE_ZEROES
> > > and make sure no existing data before the range is lost and the
> > > entire range is zeroed?
> > > 
> > 
> > I added FALLOC_FL_WRITE_ZEROES support to ltp (both fsx and fsstress).
> > For example, generic/363 tests for unaligned writes and checks for any
> > stale data. By default, I think we do unaligned reads, writes and
> > truncate in fsx.
> 
> But I guess not unaligned FALLOC_FL_WRITE_ZEROES?

        -r readbdy: 4096 would make reads page aligned (default 1)
        -t truncbdy: 4096 would make truncates page aligned (default 1)
        -w writebdy: 4096 would make writes page aligned (default 1)

FALLOC_FL_WRITE_ZEROES comes under truncate. So I would assume we also
do that. That is how I also found the issue with offset > EOF. I will
take a look or else, I will add a test case to test this condition!

Thanks.
--
Pankaj