preadv2/pwritev2 updates

[Christoph Hellwig]

On Thu, Oct 02, 2014 at 08:26:37AM +1000, Dave Chinner wrote:
> On Wed, Oct 01, 2014 at 11:04:51PM +0200, Christoph Hellwig wrote:
> > Hi Miklos,
> > 
> > attached are the patches that go on top of your
> > "[RFC v3 0/4] vfs: Non-blockling buffered fs read (page cache only)"
> > series.  The first one adds RWF_NONBLOCK to XFS, the other two
> > add a new RWF_DSYNC flag that adds a per-operation O_DSYNC flag.
> 
> Christoph, any plans to add these new syscalls to xfs_io and
> data integrity tests for the new RWF_DSYNC flag?

I've got some hacked up xfs_io support, but Milosz was planning a
slight revision of the syscall interface that I'm still waiting for.

How would you want to automatically test for data integrity?  That requires
a powerfail or crash unfortunately and we don't have good infrastructure
for that yet.  I've tested it by adding a printk that RWF_DSYNC triggers
the same code path as O_DSYNC.