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Date: Mon, 10 Jun 2019 10:04:30 +0100
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Subject: Re: [Virtio-fs] [PATCH] virtiofsd: enable PARALLEL_DIROPS during
	INIT
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To: Miklos Szeredi <mszeredi@redhat.com>
Cc: virtio-fs@redhat.com

* Miklos Szeredi (mszeredi@redhat.com) wrote:
> On Fri, Jun 7, 2019 at 9:23 PM Dr. David Alan Gilbert
> <dgilbert@redhat.com> wrote:
> >
> > * Miklos Szeredi (mszeredi@redhat.com) wrote:
> > > On Fri, Jun 7, 2019 at 8:33 PM Dr. David Alan Gilbert
> > > <dgilbert@redhat.com> wrote:
> > > >
> > > > * Liu Bo (bo.liu@linux.alibaba.com) wrote:
> > > > > On Fri, Jun 07, 2019 at 04:21:47PM +0100, Dr. David Alan Gilbert wrote:
> > > > > > * Liu Bo (bo.liu@linux.alibaba.com) wrote:
> > > > > > > lookup is a RO operations, PARALLEL_DIROPS can be enabled.
> > > > > > >
> > > > > > > Signed-off-by: Liu Bo <bo.liu@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?
> 
> Yes, since no shared data is used between readdir instances.

OK, in that case

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

and added to my tree.


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