[U-Boot] [PATCH 1/4] nfs: convert supported_nfs_versions bitfield to an enum

[Joe Hershberger]

Hi Christian,

On Mon, Oct 1, 2018 at 8:57 AM Christian Gmeiner
<christian.gmeiner at gmail.com> wrote:
>
> Hi Wolfgang
>
> >
> > In message <20181001094646.11539-1-christian.gmeiner at gmail.com> you wrote:
> > > From: Thomas RIENOESSL <thomas.rienoessl at bachmann.info>
> > >
> > > Prep. work to support nfs v1.
> >
> > Hm... as you are putting efforts into NFS support...
> >
> > Here comes a more general question:
> >
> > I wonder if it's worth the work on NFS at all, or if we should
> > remove NFS support from U-Boot alltogether?
> >
> > 1) We support only NFS v2 (and v3) in U-Boot, and most standard Linux
> >    distros support only v4 in their default configurations.
> >
>
> Linux is not the only operating system used in the world. My NFSv1
> server runs on a vxWorks 5 device which
> I need to support - sadly.
>
> > 2) We support only UDP, but most standard Linux distros support only
> >    TCP in their default configurations (see [1])
> >
> >    [1] http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=commitdiff;h=fbd7623dd8d5e418e7cb369d4026d5368f7c46a6
> >
> > Try a NFS download from any recent Linux distro (i. e. one including
> > nfs-utils 2.3.1 or later)...
> >
>
> That is true.
>
> >
> > I feel a half-way solution is unsatisfactory, but the way for the
> > Real Thing (TM) is a pretty long one...
> >
> > The fact that nobody compained yet that NFS stopped working fo him
> > suggests that there are only very, very few users of NFS at all.
> > If one of these is willing to step up and fix this for real, he is
> > of course more than welcome.  But if not - should we not remove the
> > more or less obsolete code?
> >
>
> As u-boot is lacking TCP support this is quite a challenging task. I
> have seen some work in progress
> patches, which I have reviewed and hoped that it helps to get them
> further.

I'm trying to get those patches into a state that they are acceptable,
but currently they are pretty brittle. I've not actually seen them
work, though the contributor says they do in some case. I had to do
some work to have the series just not break UDP functionality, so we
have more work to do there.

> I am also
> interested in using ftp directly in u-boot. At the moment we are using
> uip as tcp stack and hacked
> together a ftp client.

I was contemplating if using something like that or lwip would be
better than rolling our own, but my concern is both how configurable
those stacks are to make them lean as well as adding an external
dependency / forking their code into our repo. Not excited about
either.

> If you want to remove nfs all together I need to keep nfs in our
> downstream repo which is kinda sad but
> doable.

I think that if it is in use by you, then it's ok to keep around...
especially if you are contributing to make it more capable. I would
ask that you come up with a way to test the functionality in one of
the travis tests.

Cheers,
-Joe

> --
> greets
> --
> Christian Gmeiner, MSc
>
> https://christian-gmeiner.info
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