Re: nfs hang

On Thu, Nov 13, 2025 at 4:51 PM Mark Millard <marklmi@yahoo.com> wrote:
>
> Ronald Klop <ronald_at_FreeBSD.org> wrote on
> Date: Thu, 13 Nov 2025 17:17:48 UTC :
>
> > Op 13-11-2025 om 14:06 schreef Rick Macklem:
> > > On Thu, Nov 13, 2025 at 2:45 AM Ronald Klop <ronald@freebsd.org> wrote:
> > >>
> > >> Op 13-11-2025 om 11:41 schreef Ronald Klop:
> > >>> . . .
> > >>>
> > >>>
> > >>
> > >>
> > >> . . .
> > > Do you have more than one client mounting the file system?
> > > If you do, make sure they all have different /etc/hostid's.
> > > (Cloning a system disk without deleting /etc/hostid can
> > > result in multiple clients with the same /etc/hostid. That
> > > mean they are "the same client" to the NFSv4 server
> > > and that can cause the above.)
> > >
> > > If this is not the problem, I don't know why you'd see the
> > > above but I suspect the above explains the hang.
> > >
> > > rick
> > >
> >
> >
> > Two clients. Both have different /etc/hostid.
> >
> > I noticed that the procstat stacks start with "null_reclaim". And poudriere null-mounts the nfs mounts in the poudriere-jails.
>
> Do the poudriere jails on each host use the host's /etc/hostid (by content)?
>
> Any worries about needing poudriere jail /etc/hostid content uniqueness?
From NFSv4's point of view, /etc/hostid is used at mount time.
The client will use the one outside of any jail, since that is where the
mount is done from.

Now, although I was thinking about the client (since that is where
the hangs occur), it might be an issue if you were running the nfsd
in multiple jails that have the same /etc/hostid as well.
--> The server identifies itself to the client via the /etc/hostid and
     a different identity means different server.
     However, it could be a problem if the servers in different jails
     return the "same server" from the same /etc/hostid.

I'll admit it as been years since I did the "run nfsd in a vnet jail"
code and I don't remember if the use of /etc/hostid is vnet'd or
not.

rick

>
> > Could nfs+nullfs give some trouble? Or maybe it is just nullfs that hangs everything and the nfs stuff is just a result of it.
> >
> > At the same moment I had git hanging on a non-NFS mount. See attachment for the procstat which also includes nfs-calls.
>
> ===
> Mark Millard
> marklmi at yahoo.com
>