Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso <carnil@debian.org>]

Hi Steve,

On Tue, Oct 08, 2024 at 06:12:58AM -0400, Steve Dickson wrote:
> 
> 
> On 10/3/24 12:58 PM, Salvatore Bonaccorso wrote:
> > Hi Steve, hi linux-nfs people,
> > 
> > it got reported twice in Debian that  NFSv4 referrals are broken when
> > junction support is disabled. The two reports are at:
> > 
> > https://bugs.debian.org/1035908
> > https://bugs.debian.org/1083098
> > 
> > While arguably having junction support seems to be the preferred
> > option, the bug (or maybe unintended behaviour) arises when junction
> > support is not enabled (this for instance is the case in the Debian
> > stable/bookworm version, as we cannot simply do such changes in a
> > stable release; note later relases will have it enabled).
> > 
> > The "breakage" seems to be introduced with 15dc0bead10d ("exportd:
> > Moved cache upcalls routines  into libexport.a"), so
> > nfs-utils-2-5-3-rc6 as this will mask behind the #ifdef
> > HAVE_JUNCTION_SUPPORT's code which seems needed to support the refer=
> > in /etc/exports.
> > 
> > I had a quick conversation with Cuck offliste about this, and I can
> > hopefully state with his word, that yes, while nfsref is the direction
> > we want to go, we do not want to actually disable refer= in
> > /etc/exports.
> +1
> 
> > 
> > Steve, what do you think? I'm not sure on the best patch for this,
> > maybe reverting the parts masking behind #ifdef HAVE_JUNCTION_SUPPORT
> > which are touched in 15dc0bead10d would be enough?
> Yeah there is a lot of change with 15dc0bead10d
> 
> Let me look into this... At the up coming Bake-a-ton [1]

Thanks a lot for that, looking forward then to a fix which we might
backport in Debian to the older version as well.

Regards,
Salvatore