[Virtio-fs] [PATCH] virtiofsd: enable PARALLEL_DIROPS during INIT

[Dr. David Alan Gilbert]

* Miklos Szeredi (mszeredi at redhat.com) wrote:
> On Fri, Jun 7, 2019 at 8:33 PM Dr. David Alan Gilbert
> <dgilbert at redhat.com> wrote:
> >
> > * Liu Bo (bo.liu at linux.alibaba.com) wrote:
> > > On Fri, Jun 07, 2019 at 04:21:47PM +0100, Dr. David Alan Gilbert wrote:
> > > > * Liu Bo (bo.liu at linux.alibaba.com) wrote:
> > > > > lookup is a RO operations, PARALLEL_DIROPS can be enabled.
> > > > >
> > > > > Signed-off-by: Liu Bo <bo.liu at linux.alibaba.com>
> > > >
> > > > I'm not too sure what this is doing; and why doesn't upstream libfuse
> > > > have this?
> > >
> > > I'm not sure why libfuse doesn't include the capability, but AFAICT this
> > > is needed for practical use.
> >
> > Miklos: Do you know what the rules are around PARALLEL_DIROPS and why
> > the upstream libfuse doesn't have it eanbled?
> 
> Not sure why libfuse3 wouldn't have it enabled by default, probably an
> omission.  Having said that, the reason this is opt in is that old
> filesystems might rely on the serialized behavior, so back
> compatibility requires that we have this turned off by default, so now
> libfuse3 has the same problem...

So for us (virtio-fs) is it always safe?

Dave

> Thanks,
> Miklos
--
Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK