Mount NFSv4.1/NFSv4.2 filesystem in barebox?

Mount NFSv4.1/NFSv4.2 filesystem in barebox?

[Martin Wege]

Hello!

Does barebox have support to mount a NFSv4.1/NFSv.2 filesystem?

Thanks,
Martin

Re: Mount NFSv4.1/NFSv4.2 filesystem in barebox?

[Ahmad Fatoum]

Hello Martin,

On 10/25/26 22:07, Martin Wege wrote:
> Hello!
> 
> Does barebox have support to mount a NFSv4.1/NFSv.2 filesystem?

No, the barebox support is for NFSv3 over UDP. This does not prevent you
from using NFSv4/TCP during kernel boot up for the rootfs however.

We would like to support NFSv4 eventually, but given that the we had
to fix a fair share of security issues with the current network stack
and NFSv3 implementation, we should to try to avoid repeating this
in future.

Incidentally, I just created a PR for rust support in barebox:
https://github.com/barebox/barebox/pull/96

The goal is to add smoltcp as TCP/IP stack on top of it.

Then we can look towards supporting TCP protocols like HTTP and NFSv4,
but it will take a while.

This may be the third time that someone asked for NFSv4 support on the
mailing list and it would be useful to know how are you going to use it
and where NFSv3/UDP falls short. Is this because you are using Linux
kernel-nfs-server and NFSv3/UDP is not enabled by your distro or is it
because of something else?

Cheers,
Ahmad

> 
> Thanks,
> Martin
> 


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Re: Mount NFSv4.1/NFSv4.2 filesystem in barebox?

[Martin Wege]

On Mon, Oct 26, 2026 at 8:57 AM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>
> Hello Martin,
>
> On 10/25/26 22:07, Martin Wege wrote:
> > Hello!
> >
> > Does barebox have support to mount a NFSv4.1/NFSv.2 filesystem?
>
> No, the barebox support is for NFSv3 over UDP. This does not prevent you
> from using NFSv4/TCP during kernel boot up for the rootfs however.
>
> We would like to support NFSv4 eventually, but given that the we had
> to fix a fair share of security issues with the current network stack
> and NFSv3 implementation, we should to try to avoid repeating this
> in future.
>
> Incidentally, I just created a PR for rust support in barebox:
> https://github.com/barebox/barebox/pull/96
>
> The goal is to add smoltcp as TCP/IP stack on top of it.
>
> Then we can look towards supporting TCP protocols like HTTP and NFSv4,
> but it will take a while.
>
> This may be the third time that someone asked for NFSv4 support on the
> mailing list and it would be useful to know how are you going to use it
> and where NFSv3/UDP falls short. Is this because you are using Linux
> kernel-nfs-server and NFSv3/UDP is not enabled by your distro or is it
> because of something else?

Four issues:
1. NIST2 requirements basically EXCLUDE NFSv2/NFSv3 over UDP
2. NFSv2 and to some extent NFSv3+NFSv4.0 are declared as "obsolete"
by IETF, which again is an issue for NIST2. The whole thing has been
"red flagged" by certification authorities now several times.
3. NFSv2/NFSv3 over UDP is FRAGILE like frozen glass in a volcano
4. NFSv4.1 has much better performance and features which would make
starting through a bigger initramfs faster. Example: You would prefer
that your glass cockpit in a plan reboots a bit faster if something
went wrong (power outage) mid-flight.

Thanks,
Martin