Re: NFSv4 referrals broken when not enabling junction support

[Steve Dickson <steved@redhat.com>]

On 11/25/24 11:57 PM, Salvatore Bonaccorso wrote:
> Hi Steve,
> 
> On Sat, Oct 26, 2024 at 09:04:01AM -0400, Steve Dickson wrote:
>>
>>
>> On 10/25/24 4:14 PM, Salvatore Bonaccorso wrote:
>>> Hi Steve,
>>>
>>> On Sun, Oct 20, 2024 at 04:37:10PM +0200, Salvatore Bonaccorso wrote:
>>>> 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.
>>>
>>> Hope the Bake-a-ton was productive :)
>>>
>>> Did you had a chance to look at this issue beeing there?
>> Yes I did... and we did talk about the problem.... still looking into it.
> 
> Reviewing the open bugs in Debian I remembered of this one. If you
> have already a POC implementation/bugfix available, would it help if I
> prod at least the two reporters in Debian to test the changes?
> 
> Thanks a lot for your work, it is really appreciated!
I was not able to reproduce this at the Bakeathon
with the latest nfs-utils... and today I took another
look today...

Would mind showing me the step that cause the error
and what is the error?

tia,

steved.