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

Christoph Hellwig <[email protected]> Thu, 18 Jun 2026 02:36:00 -0700
Newsgroups org.kernel.vger.linux-api,org.kernel.vger.linux-fsdevel,org.kernel.vger.linux-xfs
Message-ID <[email protected]>
On Thu, Jun 18, 2026 at 11:28:15AM +0200, Pankaj Raghav (Samsung) wrote:
> > 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!

A targeted test using xfs_io that does FALLOC_FL_WRITE_ZEROES on an
unaligned range and then checks that the data around it is preserved
while the unaligned data in the range is zeroed would also be useful.