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

[Liu Bo]

On Fri, Jun 07, 2019 at 08:23:46PM +0100, Dr. David Alan Gilbert wrote:
> * 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?
>

FYI, my first round of limited testing (dbench4, fsmark, fstests) didn't say no.

thanks,
-liubo