[PATCH v2 0/4] NFSv1 support

[Simon Glass]

Hi Peter,

On Sat, 25 Mar 2023 at 02:14, Peter Robinson <pbrobinson at gmail.com> wrote:
>
> On Fri, Mar 24, 2023 at 1:05 PM Christian Gmeiner
> <christian.gmeiner at gmail.com> wrote:
> >
> > Hi Peter
> >
> > > >
> > > > Hi Peter,
> > > >
> > > > Am Fr., 24. März 2023 um 11:10 Uhr schrieb Peter Robinson
> > > > <pbrobinson at gmail.com>:
> > > > >
> > > > > On Fri, Mar 24, 2023 at 9:35 AM Christian Gmeiner
> > > > > <christian.gmeiner at gmail.com> wrote:
> > > > > >
> > > > > > Hi Peter,
> > > > > >
> > > > > > > >
> > > > > > > > This patch series adds support for NFSv1 and is more
> > > > > > > > or less a rebased version of an older series.
> > > > > > > >
> > > > > > > > During V1 there was a discussion if it really makes sense
> > > > > > > > to bring more features into the network stack of U-Boot as it
> > > > > > > > is just a bootloader. As TCP support landed I thought I might
> > > > > > > > give this patch series another try.
> > > > > > >
> > > > > > > So the real question is what use does this bring? TCP is useful
> > > > > > > because it can enable support for modern features like UEFI HTTP boot.
> > > > > > > What is the use of NFSc1? The Linux kernel is removing support for
> > > > > > > NFSv2 and according to wikipedia v1 was only ever used internally to
> > > > > > > Sun so I'm not sure what the wider use of this functionality would be?
> > > > > > >
> > > > > >
> > > > > > You know there are other operating systems used in the wild. One of them is
> > > > > > vxworks. The company I work for supports software versions for more than 10
> > > > > > years and customers do not want to update to newer software versions
> > > > > > as the process
> > > > > > of approval for wind turbines/parks is very costly and time intensive.
> > > > > > For security
> > > > > > issues we provide patches for older versions that the customers are
> > > > > > switching to.
> > > > >
> > > > > Are there deployments that are updating to new versions of U-Boot that
> > > > > require NFSv1 though?
> > > > >
> > > >
> > > > Sadly, yes .. There are so called drop-in replacements for "processor
> > > > modules" where
> > > > we update the old design (e.g. AMD LX800 based 26G MHz one) to a new
> > > > recent Intel SoC.
> > > > Our customer can order a replacement HW for the old LX800 based design
> > > > and they get
> > > > the new one with fully compatible software.
> > > >
> > > > > > We are shipping devices right now which are based on vxworks 5. Some
> > > > > > customers are using our "processor modules" as NFS server for e.g. other
> > > > > > "processor modules" to boot from. If you want/need I can go into further details
> > > > > > about our use case.
> > > > >
> > > > > So they're using a 25 year old version of vxworks with the latest
> > > > > version of U-Boot? And vxworks supports only NFSv1, and not NFSv2,
> > > > > which has been out since 1989 and was the first version that even Sun
> > > > > supported publicly?
> > > > >
> > > >
> > > > There are newer versions of NFS supported on more recent vxworks
> > > > versions but as our
> > > > customers do not want to change software of an approved wind turbine we need to
> > > > support the old feature.
> > > >
> > > > Also we are allowed to include only critical fixes in patch version,
> > > > which can be used
> > > > without the whole approval process. For any new feature our customer would
> > > > need to redo the whole approval process.
> > >
> > > Yet they allow you to update the entire version of U-Boot to the latest one?
> >
> > U-Boot is used as coreboot payload and both together are the bios. None of our
> > customers do bios updates in the field as the risk of bricking the
> > device is too high.
> >
> > >
> > > I understand how the process works when they don't want to change
> > > things, but it doesn't make sense to update U-Boot to the latest
> > > version yet not other pieces of the infrastructure. NFSv1 was
> > > basically obsolete from the outset because Sun's first public release
> > > was v2.
> > >
> > > It doesn't make sense to me to upstream a long obsolete version, and
> > > no doubt insecure, version of a protocol which is seemingly used by a
> > > single customer of yours.
> >
> > I am fine with that decision .. but I hope you know that NFSv2 is an
> > insecure version too!
>
> Oh I'm well aware of that, it's at least been more widely reviewed and
> the issues are better known. Personally I've never particularly seen
> the point of NFS in a firmware at all. These days I think HTTP would
> provide equivalence of functionality with the better support for
> things like proxy/caching/CDN and other such functionality.

But here we are talking about supporting old software. So it doesn't
much matter that HTTP is now available.

Regards,
Simon


>
> > >
> > > > >
> > > > > > So I know It is a quite specific use case but we want to upstream most
> > > > > > of our downstream
> > > > > > patches.
> > > > > >
> > > > > > Btw. if this patch series will not land does this mean NFSv2 will die too soon?
> > > > >
> > > > > At least NFSv2 is supported to some degree whereas it seems NFSv1 is
> > > > > something that's special to vxworks, how are people supposed to test
> > > > > it? I don't see any tests in your patchset and I'm not sure how it's
> > > > > useful outside of the legacy vxmworks use case.
> > > > >
> > > >
> > > > I thought that this unit test topic will pop up and we have written
> > > > some last week. I will
> > > > include them in the next version of this patchset.
> > > >
> > > > Btw why are there no NFSv2, NFSv3 unit tests in U-Boot? How are people
> > > > supposed to
> > > > test it?
> > >
> > > The NFSv2 code was contributed before it was decided that new
> > > functionality should come with tests that can run in CI.
> > >
> > > Where would the NFSv1 server come from for this for testing in CI?
> >
> > You convinced me to stop thinking about upstreaming NFSv1 support.
> >
> > --
> > thanks
> > --
> > Christian Gmeiner, MSc
> >
> > https://christian-gmeiner.info/privacypolicy