Re: [PATCH v11 00/20] nfs/nfsd: add support for localio

NeilBrown
2024-07-05T22:08:19Z

On Fri, 05 Jul 2024, Christoph Hellwig wrote:
> On Thu, Jul 04, 2024 at 02:31:46PM -0400, Mike Snitzer wrote:
> > Some new layout misses the entire point of having localio work for
> > NFSv3 and NFSv4. NFSv3 is very ubiquitous.
>
> I'm getting tird of bringing up this "oh NFSv3" again and again without
> any explanation of why that matters for communication insides the
> same Linux kernel instance with a kernel that obviously requires
> patching. Why is running an obsolete protocol inside the same OS
> instance required. Maybe it is, but if so it needs a very good
> explanation.

I would like to see a good explanation for why NOT NFSv3.
I don't think NFSv3 is obsolete. The first dictionary is "No longer in
use." which certainly doesn't apply.
I think "deprecated" is a more relevant term. I believe that NFSv2 has
been deprecated. I believe that NFSv4.0 should be deprecated. But I
don't see any reason to consider NFSv3 to be deprecated.

>
> > And in this localio series, flexfiles is trained to use localio.
> > (Which you apparently don't recognize or care about because nfsd
> > doesn't have flexfiles server support).
>
> And you fail to explain why it matters. You are trying to sell this
> code, you better have an explanation why it's complicated and convoluted
> as hell. So far we are running in circles but there has been no clear
> explanation of use cases.

Please avoid sweeping statements like "complicated and convoluted"
without backing them up with specifics.
I don't particularly want to defend the current localio protocol, and I
certainly see a number of points which can and must be improved. But it
isn't clear to me that the big picture is either complicated or
convoluted. Please provide details.

Thanks,
NeilBrown