NFSv4 referrals broken when not enabling junction support

NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

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.

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?

Thanks a lot already in advance!

Regards,
Salvatore

Re: NFSv4 referrals broken when not enabling junction support

[Steve Dickson]

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]

steved.

[1] http://www.nfsv4bat.org/Events/2024/Oct/BAT/index.html

Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

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

Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

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?

Regards,
Salvatore

Re: NFSv4 referrals broken when not enabling junction support

[Steve Dickson]

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.

steved.
> 
> Regards,
> Salvatore
> 

Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

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.

Many thanks for the update!

Regards,
Salvatore

Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

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!

Regards,
Salvatore

Re: NFSv4 referrals broken when not enabling junction support

[Steve Dickson]

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.

Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

Hi Steve,

On Mon, Dec 02, 2024 at 01:26:46PM -0500, Steve Dickson wrote:
> 
> 
> 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?

Let me ask the two reporters in Debian, Cc'ed.

Sam, Anton can you provide here how to reproduce the issue with
nfs-utils which you reported?

Context:
- https://bugs.debian.org/1035908
- https://bugs.debian.org/1083098

Regards,
Salvatore

Re: NFSv4 referrals broken when not enabling junction support

[Steve Dickson]

On 12/2/24 2:46 PM, Salvatore Bonaccorso wrote:
> Hi Steve,
> 
> On Mon, Dec 02, 2024 at 01:26:46PM -0500, Steve Dickson wrote:
>>
>>
>> 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?
> 
> Let me ask the two reporters in Debian, Cc'ed.
> 
> Sam, Anton can you provide here how to reproduce the issue with
> nfs-utils which you reported?
> 
Please note setting "enable-junction=no" does disable
the referral code. aka in dump_to_cache()

#ifdef HAVE_JUNCTION_SUPPORT
         write_fsloc(&bp, &blen, exp);
#endif

So unless I'm not understanding something (which is very possible :-) )
disabling junctions also disables referrals.

steved.

> Context:
> - https://bugs.debian.org/1035908
> - https://bugs.debian.org/1083098
> 
> Regards,
> Salvatore
> 

Re: NFSv4 referrals broken when not enabling junction support

[Chuck Lever III]

> On Dec 2, 2024, at 2:46 PM, Salvatore Bonaccorso <carnil@debian.org> wrote:
> 
> Hi Steve,
> 
> On Mon, Dec 02, 2024 at 01:26:46PM -0500, Steve Dickson wrote:
>> 
>> 
>> 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?
> 
> Let me ask the two reporters in Debian, Cc'ed.
> 
> Sam, Anton can you provide here how to reproduce the issue with
> nfs-utils which you reported?
> 
> Context:
> - https://bugs.debian.org/1035908
> - https://bugs.debian.org/1083098

I was able to reproduce this by building nfs-utils
from scratch with the "--disable-junction" configure
option. Install the server-side user space components
from this build.

Then add a "refer=" export option and try to use that
export from a client.


--
Chuck Lever

Re: NFSv4 referrals broken when not enabling junction support

[Chuck Lever III]

> On Dec 2, 2024, at 2:57 PM, Steve Dickson <steved@redhat.com> wrote:
> 
> 
> 
> On 12/2/24 2:46 PM, Salvatore Bonaccorso wrote:
>> Hi Steve,
>> On Mon, Dec 02, 2024 at 01:26:46PM -0500, Steve Dickson wrote:
>>> 
>>> 
>>> 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?
>> Let me ask the two reporters in Debian, Cc'ed.
>> Sam, Anton can you provide here how to reproduce the issue with
>> nfs-utils which you reported?
> Please note setting "enable-junction=no" does disable
> the referral code. aka in dump_to_cache()
> 
> #ifdef HAVE_JUNCTION_SUPPORT
>        write_fsloc(&bp, &blen, exp);
> #endif
> 
> So unless I'm not understanding something (which is very possible :-) )
> disabling junctions also disables referrals.

Disabling junction support is not supposed to disable referrals.
Referrals worked long before junction support was added, and
stopped working in this configuration with the commit that
Salvatore bisected to.


> steved.
> 
>> Context:
>> - https://bugs.debian.org/1035908
>> - https://bugs.debian.org/1083098
>> Regards,
>> Salvatore
> 

--
Chuck Lever

Re: NFSv4 referrals broken when not enabling junction support

[Salvatore Bonaccorso]

Hi Steve,


On Mon, Dec 02, 2024 at 02:57:54PM -0500, Steve Dickson wrote:
> 
> 
> On 12/2/24 2:46 PM, Salvatore Bonaccorso wrote:
> > Hi Steve,
> > 
> > On Mon, Dec 02, 2024 at 01:26:46PM -0500, Steve Dickson wrote:
> > > 
> > > 
> > > 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?
> > 
> > Let me ask the two reporters in Debian, Cc'ed.
> > 
> > Sam, Anton can you provide here how to reproduce the issue with
> > nfs-utils which you reported?
> > 
> Please note setting "enable-junction=no" does disable
> the referral code. aka in dump_to_cache()
> 
> #ifdef HAVE_JUNCTION_SUPPORT
>         write_fsloc(&bp, &blen, exp);
> #endif
> 
> So unless I'm not understanding something (which is very possible :-) )
> disabling junctions also disables referrals.

yes, and this is actually the problem reported here. If you have
distribution which cannot enable (yet) junction support, then referral
support regressed after 15dc0bead10d ("exportd: Moved cache upcalls
routines into libexport.a").

It was argued that, while is is clear that enabling junction support
is the preferred option (and we have done so in later versions in
Debian), when this is not enabled, and after nfs-utils-2-5-3-rc6, this
regressed in the referrals support.

My understanding is that Chuck in principle agrees that this is to be
considered a bug.

Hope this helps?

Regards,
Salvatore

[nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Scott Mayhew]

Commit 15dc0bea ("exportd: Moved cache upcalls routines into
libexport.a") caused write_fsloc() to be elided when junction support is
disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
be around actual junction code).

Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 support/export/cache.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/support/export/cache.c b/support/export/cache.c
index 6c0a44a3..3a8e57cf 100644
--- a/support/export/cache.c
+++ b/support/export/cache.c
@@ -34,10 +34,7 @@
 #include "pseudoflavors.h"
 #include "xcommon.h"
 #include "reexport.h"
-
-#ifdef HAVE_JUNCTION_SUPPORT
 #include "fsloc.h"
-#endif
 
 #ifdef USE_BLKID
 #include "blkid/blkid.h"
@@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
 	*dp = d;
 }
 
-#ifdef HAVE_JUNCTION_SUPPORT
 static void write_fsloc(char **bp, int *blen, struct exportent *ep)
 {
 	struct servers *servers;
@@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
 	qword_addint(bp, blen, servers->h_referral);
 	release_replicas(servers);
 }
-#endif
 
 static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
 {
@@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
 		qword_addint(&bp, &blen, exp->e_anongid);
 		qword_addint(&bp, &blen, fsidnum);
 
-#ifdef HAVE_JUNCTION_SUPPORT
 		write_fsloc(&bp, &blen, exp);
-#endif
 		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
 		if (exp->e_uuid == NULL || different_fs) {
 			char u[16];
-- 
2.46.2

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Roland Mainz]

On Mon, Dec 2, 2024 at 9:30 PM Scott Mayhew <smayhew@redhat.com> wrote:
> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
> libexport.a") caused write_fsloc() to be elided when junction support is
> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
> be around actual junction code).
>
> Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
[snip]

Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>

----

Bye,
Roland
-- 
  __ .  . __
 (o.\ \/ /.o) roland.mainz@nrubsig.org
  \__\/\/__/  MPEG specialist, C&&JAVA&&Sun&&Unix programmer
  /O /==\ O\  TEL +49 641 3992797
 (;O/ \/ \O;)

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Chuck Lever]

On Mon, Dec 02, 2024 at 03:30:46PM -0500, Scott Mayhew wrote:
> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
> libexport.a") caused write_fsloc() to be elided when junction support is
> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
> be around actual junction code).

I agree, this looks like an unintended regression in 15dc0bea.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>

I suggest adding:

Link: https://bugs.debian.org/1035908
Link: https://bugs.debian.org/1083098

> Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
> ---
>  support/export/cache.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/support/export/cache.c b/support/export/cache.c
> index 6c0a44a3..3a8e57cf 100644
> --- a/support/export/cache.c
> +++ b/support/export/cache.c
> @@ -34,10 +34,7 @@
>  #include "pseudoflavors.h"
>  #include "xcommon.h"
>  #include "reexport.h"
> -
> -#ifdef HAVE_JUNCTION_SUPPORT
>  #include "fsloc.h"
> -#endif
>  
>  #ifdef USE_BLKID
>  #include "blkid/blkid.h"
> @@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
>  	*dp = d;
>  }
>  
> -#ifdef HAVE_JUNCTION_SUPPORT
>  static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>  {
>  	struct servers *servers;
> @@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>  	qword_addint(bp, blen, servers->h_referral);
>  	release_replicas(servers);
>  }
> -#endif
>  
>  static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
>  {
> @@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
>  		qword_addint(&bp, &blen, exp->e_anongid);
>  		qword_addint(&bp, &blen, fsidnum);
>  
> -#ifdef HAVE_JUNCTION_SUPPORT
>  		write_fsloc(&bp, &blen, exp);
> -#endif
>  		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
>  		if (exp->e_uuid == NULL || different_fs) {
>  			char u[16];
> -- 
> 2.46.2
> 
> 

-- 
Chuck Lever

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Steve Dickson]

Hey,

On 12/2/24 3:30 PM, Scott Mayhew wrote:
> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
> libexport.a") caused write_fsloc() to be elided when junction support is
> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
> be around actual junction code).
Why not just take the enable_junction config variable
out of configure.ac as well?

If we want junctions/referrals (which are the same)
IMHO... on all the time... Lets not be able to
turn them off at all?

Point being... if we are going remove 3 of the 4
HAVE_JUNCTION_SUPPORT ifdefs... let get ride of
all of them.

steved.
> 
> Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
> ---
>   support/export/cache.c | 7 -------
>   1 file changed, 7 deletions(-)
> 
> diff --git a/support/export/cache.c b/support/export/cache.c
> index 6c0a44a3..3a8e57cf 100644
> --- a/support/export/cache.c
> +++ b/support/export/cache.c
> @@ -34,10 +34,7 @@
>   #include "pseudoflavors.h"
>   #include "xcommon.h"
>   #include "reexport.h"
> -
> -#ifdef HAVE_JUNCTION_SUPPORT
>   #include "fsloc.h"
> -#endif
>   
>   #ifdef USE_BLKID
>   #include "blkid/blkid.h"
> @@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
>   	*dp = d;
>   }
>   
> -#ifdef HAVE_JUNCTION_SUPPORT
>   static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>   {
>   	struct servers *servers;
> @@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>   	qword_addint(bp, blen, servers->h_referral);
>   	release_replicas(servers);
>   }
> -#endif
>   
>   static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
>   {
> @@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
>   		qword_addint(&bp, &blen, exp->e_anongid);
>   		qword_addint(&bp, &blen, fsidnum);
>   
> -#ifdef HAVE_JUNCTION_SUPPORT
>   		write_fsloc(&bp, &blen, exp);
> -#endif
>   		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
>   		if (exp->e_uuid == NULL || different_fs) {
>   			char u[16];

Re: NFSv4 referrals broken when not enabling junction support

[Steve Dickson]

On 12/2/24 3:02 PM, Chuck Lever III wrote:
> 
> 
>> On Dec 2, 2024, at 2:57 PM, Steve Dickson <steved@redhat.com> wrote:
>>
>>
>>
>> On 12/2/24 2:46 PM, Salvatore Bonaccorso wrote:
>>> Hi Steve,
>>> On Mon, Dec 02, 2024 at 01:26:46PM -0500, Steve Dickson wrote:
>>>>
>>>>
>>>> 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?
>>> Let me ask the two reporters in Debian, Cc'ed.
>>> Sam, Anton can you provide here how to reproduce the issue with
>>> nfs-utils which you reported?
>> Please note setting "enable-junction=no" does disable
>> the referral code. aka in dump_to_cache()
>>
>> #ifdef HAVE_JUNCTION_SUPPORT
>>         write_fsloc(&bp, &blen, exp);
>> #endif
>>
>> So unless I'm not understanding something (which is very possible :-) )
>> disabling junctions also disables referrals.
> 
> Disabling junction support is not supposed to disable referrals.
> Referrals worked long before junction support was added, and
> stopped working in this configuration with the commit that
> Salvatore bisected to.
Got it... thanks!

steved.
> 
> 
>> steved.
>>
>>> Context:
>>> - https://bugs.debian.org/1035908
>>> - https://bugs.debian.org/1083098
>>> Regards,
>>> Salvatore
>>
> 
> --
> Chuck Lever
> 
> 

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Steve Dickson]

On 12/2/24 4:41 PM, Chuck Lever wrote:
> On Mon, Dec 02, 2024 at 03:30:46PM -0500, Scott Mayhew wrote:
>> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
>> libexport.a") caused write_fsloc() to be elided when junction support is
>> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
>> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
>> be around actual junction code).
> 
> I agree, this looks like an unintended regression in 15dc0bea.
> 
> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
> 
> I suggest adding:
> 
> Link: https://bugs.debian.org/1035908
> Link: https://bugs.debian.org/1083098
> 
>> Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
>> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fair enough... I'm also going to tone down
the "bogus" to "unnecessary"... Lets keep it civil.

steved.

>> ---
>>   support/export/cache.c | 7 -------
>>   1 file changed, 7 deletions(-)
>>
>> diff --git a/support/export/cache.c b/support/export/cache.c
>> index 6c0a44a3..3a8e57cf 100644
>> --- a/support/export/cache.c
>> +++ b/support/export/cache.c
>> @@ -34,10 +34,7 @@
>>   #include "pseudoflavors.h"
>>   #include "xcommon.h"
>>   #include "reexport.h"
>> -
>> -#ifdef HAVE_JUNCTION_SUPPORT
>>   #include "fsloc.h"
>> -#endif
>>   
>>   #ifdef USE_BLKID
>>   #include "blkid/blkid.h"
>> @@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
>>   	*dp = d;
>>   }
>>   
>> -#ifdef HAVE_JUNCTION_SUPPORT
>>   static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>>   {
>>   	struct servers *servers;
>> @@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>>   	qword_addint(bp, blen, servers->h_referral);
>>   	release_replicas(servers);
>>   }
>> -#endif
>>   
>>   static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
>>   {
>> @@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
>>   		qword_addint(&bp, &blen, exp->e_anongid);
>>   		qword_addint(&bp, &blen, fsidnum);
>>   
>> -#ifdef HAVE_JUNCTION_SUPPORT
>>   		write_fsloc(&bp, &blen, exp);
>> -#endif
>>   		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
>>   		if (exp->e_uuid == NULL || different_fs) {
>>   			char u[16];
>> -- 
>> 2.46.2
>>
>>
> 

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Scott Mayhew]

On Mon, 02 Dec 2024, Steve Dickson wrote:

> Hey,
> 
> On 12/2/24 3:30 PM, Scott Mayhew wrote:
> > Commit 15dc0bea ("exportd: Moved cache upcalls routines into
> > libexport.a") caused write_fsloc() to be elided when junction support is
> > disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
> > that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
> > be around actual junction code).
> Why not just take the enable_junction config variable
> out of configure.ac as well?
> 
> If we want junctions/referrals (which are the same)
> IMHO... on all the time... Lets not be able to
> turn them off at all?
> 
> Point being... if we are going remove 3 of the 4
> HAVE_JUNCTION_SUPPORT ifdefs... let get ride of
> all of them.

Junctions and referrals are _not_ the same.  A junction is one mechanism
that can be used to generate a referral.  The other way to generate a
referral is with an export entry, and that is the method that stopped
working after 15dc0bea.

When you set up a referral via an export entry you use the refer=
export option, and the directory must be a mountpoint so that nfsd will
consult the export cache when the client tries to access the directory.

For example, I set up the following in /etc/exports:

/export *(rw,insecure,no_root_squash)
/export/ref     *(rw,insecure,no_root_squash,refer=/export@192.168.124.66)

After the client tries to access /export/ref, this is what I see when I
dump the export cache without my fix:

[root@rawhide ~]# cat /proc/net/rpc/nfsd.export/content
#path domain(flags)
/       *(ro,insecure,no_root_squash,sync,no_wdelay,no_subtree_check,v4root,fsid=0,sec=1)
/export *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)
/export/ref     *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)

Notice there's no refer= option.  So when the client does a LOOKUP of
/export/ref, the server treats it as a normal directory... it doesn't
return NFS4ERR_MOVED and so the client doesn't know to query
fs_locations.

Here is what the export cache looks like with my fix:

[root@rawhide ~]# cat /proc/net/rpc/nfsd.export/content
#path domain(flags)
/export *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)
/       *(ro,insecure,no_root_squash,sync,no_wdelay,no_subtree_check,v4root,fsid=0,sec=1)
/export/ref     *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,refer=/export@192.168.124.66,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)

Note the refer= option is present, and the referral works normally.

A junction is basically a fancy directory that has the user/group/other
mode bits set to 0 and the sticky bit turned on.  The original mode bits
are stored in the trusted.junction.mode extended attribute and the
referral information is stored in the trusted.junction.nfs extended
attribute.

Continuing with my previous example, I have this in my /etc/exports

[root@rawhide ~]# cat /etc/exports
/export *(rw,insecure,no_root_squash)
/export/ref     *(rw,insecure,no_root_squash,refer=/export@192.168.124.66)

Let's add a referral using a junction.

[root@rawhide ~]# nfsref add /export/junc 192.168.124.66 /export
Created junction /export/junc

In this case, /export/junc didn't previously exist, so the nfsref tool
created it.  If /export/junc did already exist, then the original mode
would be stored in the trusted.junction.mode and the original contents
of the directory would be hidden from the client (as well as
non-privileged users on the server).

You can look up the referral info using 'nfsref lookup':

[root@rawhide ~]# nfsref lookup /export/junc
192.168.124.66:/export

        NFS port:       2049
        Valid for:      0
        Currency:       -1
        Flags:          varsub(false)
        GenFlags:       writable(false), going(false), split(true)
        TransFlags:     rdma(true)
        Class:          simul(0), handle(0), fileid(0)
        Class:          writever(0), change(0), readdir(0)
        Read:           rank(0), order(0)
        Write:          rank(0), order(0)

Or you can just use getfattr if you want to see the raw xml:

[root@rawhide ~]# getfattr --only-values -d -m trusted.junction.nfs /export/junc
getfattr: Removing leading '/' from absolute path names
<?xml version="1.0" encoding="UTF-8"?>
<junction>
  <savedmode bits="755"/>
  <fileset>
    <location>
      <host name="192.168.124.66"/>
      <path>
        <component>export</component>
      </path>
      <currency>-1</currency>
      <genflags writable="false" going="false" split="true"/>
      <transflags rdma="true"/>
      <class simul="0" handle="0" fileid="0" writever="0" change="0" readdir="0"/>
      <read rank="0" order="0"/>
      <write rank="0" order="0"/>
      <flags varsub="false"/>
      <validfor>0</validfor>
    </location>
  </fileset>
</junction>

Note that since the /export/junc referral is stored in a junction, it
doesn't appear in the export info:

[root@rawhide ~]# exportfs -v
/export         <world>(sync,wdelay,hide,no_subtree_check,sec=sys,rw,insecure,no_root_squash,no_all_squash)
/export/ref     <world>(sync,wdelay,hide,no_subtree_check,refer=/export@192.168.124.66,sec=sys,rw,insecure,no_root_squash,no_all_squash)

From the client's standpoint, both style referrals work the same:

root@aion:~# mount 192.168.124.26:/export /mnt/t
root@aion:~# ls /mnt/t
junc  ref
root@aion:~# ls /mnt/t/ref
file
root@aion:~# cat /mnt/t/ref/file
I am on the referral server.
root@aion:~# grep nfs4 /proc/mounts
192.168.124.26:/export /mnt/t nfs4 rw,relatime,vers=4.2,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.26 0 0
192.168.124.66:/export /mnt/t/ref nfs4 rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.66 0 0
root@aion:~# ls /mnt/t/junc
file
root@aion:~# cat /mnt/t/junc/file
I am on the referral server.
root@aion:~# grep nfs4 /proc/mounts
192.168.124.26:/export /mnt/t nfs4 rw,relatime,vers=4.2,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.26 0 0
192.168.124.66:/export /mnt/t/ref nfs4 rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.66 0 0
192.168.124.66:/export /mnt/t/junc nfs4 rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.66 0 0


So if you want to get rid of that last #ifdef HAVE_JUNCTION_SUPPORT
then you have 2 options:

a) get rid of junctions entirely, leaving users with only the old
(relatively speaking) method for configuring referrals
b) force all packagers of nfs-utils to pull in the extra dependencies
needed to support junctions, which is the exact opposite of what the
Debian folks are requesting.

Or you can take the patch and we can continue to have both style
referrals.

-Scott
> 
> steved.
> > 
> > Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
> > Signed-off-by: Scott Mayhew <smayhew@redhat.com>
> > ---
> >   support/export/cache.c | 7 -------
> >   1 file changed, 7 deletions(-)
> > 
> > diff --git a/support/export/cache.c b/support/export/cache.c
> > index 6c0a44a3..3a8e57cf 100644
> > --- a/support/export/cache.c
> > +++ b/support/export/cache.c
> > @@ -34,10 +34,7 @@
> >   #include "pseudoflavors.h"
> >   #include "xcommon.h"
> >   #include "reexport.h"
> > -
> > -#ifdef HAVE_JUNCTION_SUPPORT
> >   #include "fsloc.h"
> > -#endif
> >   #ifdef USE_BLKID
> >   #include "blkid/blkid.h"
> > @@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
> >   	*dp = d;
> >   }
> > -#ifdef HAVE_JUNCTION_SUPPORT
> >   static void write_fsloc(char **bp, int *blen, struct exportent *ep)
> >   {
> >   	struct servers *servers;
> > @@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
> >   	qword_addint(bp, blen, servers->h_referral);
> >   	release_replicas(servers);
> >   }
> > -#endif
> >   static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
> >   {
> > @@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
> >   		qword_addint(&bp, &blen, exp->e_anongid);
> >   		qword_addint(&bp, &blen, fsidnum);
> > -#ifdef HAVE_JUNCTION_SUPPORT
> >   		write_fsloc(&bp, &blen, exp);
> > -#endif
> >   		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
> >   		if (exp->e_uuid == NULL || different_fs) {
> >   			char u[16];
> 

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Steve Dickson]

On 12/3/24 7:43 AM, Scott Mayhew wrote:
> On Mon, 02 Dec 2024, Steve Dickson wrote:
> 
>> Hey,
>>
>> On 12/2/24 3:30 PM, Scott Mayhew wrote:
>>> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
>>> libexport.a") caused write_fsloc() to be elided when junction support is
>>> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
>>> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
>>> be around actual junction code).
>> Why not just take the enable_junction config variable
>> out of configure.ac as well?
>>
>> If we want junctions/referrals (which are the same)
>> IMHO... on all the time... Lets not be able to
>> turn them off at all?
>>
>> Point being... if we are going remove 3 of the 4
>> HAVE_JUNCTION_SUPPORT ifdefs... let get ride of
>> all of them.
> 
> Junctions and referrals are _not_ the same.  A junction is one mechanism
> that can be used to generate a referral.  The other way to generate a
> referral is with an export entry, and that is the method that stopped
> working after 15dc0bea.
> 
> When you set up a referral via an export entry you use the refer=
> export option, and the directory must be a mountpoint so that nfsd will
> consult the export cache when the client tries to access the directory.
> 
> For example, I set up the following in /etc/exports:
> 
> /export *(rw,insecure,no_root_squash)
> /export/ref     *(rw,insecure,no_root_squash,refer=/export@192.168.124.66)
> 
> After the client tries to access /export/ref, this is what I see when I
> dump the export cache without my fix:
> 
> [root@rawhide ~]# cat /proc/net/rpc/nfsd.export/content
> #path domain(flags)
> /       *(ro,insecure,no_root_squash,sync,no_wdelay,no_subtree_check,v4root,fsid=0,sec=1)
> /export *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)
> /export/ref     *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)
> 
> Notice there's no refer= option.  So when the client does a LOOKUP of
> /export/ref, the server treats it as a normal directory... it doesn't
> return NFS4ERR_MOVED and so the client doesn't know to query
> fs_locations.
> 
> Here is what the export cache looks like with my fix:
> 
> [root@rawhide ~]# cat /proc/net/rpc/nfsd.export/content
> #path domain(flags)
> /export *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)
> /       *(ro,insecure,no_root_squash,sync,no_wdelay,no_subtree_check,v4root,fsid=0,sec=1)
> /export/ref     *(rw,insecure,no_root_squash,sync,wdelay,no_subtree_check,refer=/export@192.168.124.66,uuid=c4eeda84:ea1a4dcd:a043fdc1:372d7878,sec=1)
> 
> Note the refer= option is present, and the referral works normally.
> 
> A junction is basically a fancy directory that has the user/group/other
> mode bits set to 0 and the sticky bit turned on.  The original mode bits
> are stored in the trusted.junction.mode extended attribute and the
> referral information is stored in the trusted.junction.nfs extended
> attribute.
> 
> Continuing with my previous example, I have this in my /etc/exports
> 
> [root@rawhide ~]# cat /etc/exports
> /export *(rw,insecure,no_root_squash)
> /export/ref     *(rw,insecure,no_root_squash,refer=/export@192.168.124.66)
> 
> Let's add a referral using a junction.
> 
> [root@rawhide ~]# nfsref add /export/junc 192.168.124.66 /export
> Created junction /export/junc
> 
> In this case, /export/junc didn't previously exist, so the nfsref tool
> created it.  If /export/junc did already exist, then the original mode
> would be stored in the trusted.junction.mode and the original contents
> of the directory would be hidden from the client (as well as
> non-privileged users on the server).
> 
> You can look up the referral info using 'nfsref lookup':
> 
> [root@rawhide ~]# nfsref lookup /export/junc
> 192.168.124.66:/export
> 
>          NFS port:       2049
>          Valid for:      0
>          Currency:       -1
>          Flags:          varsub(false)
>          GenFlags:       writable(false), going(false), split(true)
>          TransFlags:     rdma(true)
>          Class:          simul(0), handle(0), fileid(0)
>          Class:          writever(0), change(0), readdir(0)
>          Read:           rank(0), order(0)
>          Write:          rank(0), order(0)
> 
> Or you can just use getfattr if you want to see the raw xml:
> 
> [root@rawhide ~]# getfattr --only-values -d -m trusted.junction.nfs /export/junc
> getfattr: Removing leading '/' from absolute path names
> <?xml version="1.0" encoding="UTF-8"?>
> <junction>
>    <savedmode bits="755"/>
>    <fileset>
>      <location>
>        <host name="192.168.124.66"/>
>        <path>
>          <component>export</component>
>        </path>
>        <currency>-1</currency>
>        <genflags writable="false" going="false" split="true"/>
>        <transflags rdma="true"/>
>        <class simul="0" handle="0" fileid="0" writever="0" change="0" readdir="0"/>
>        <read rank="0" order="0"/>
>        <write rank="0" order="0"/>
>        <flags varsub="false"/>
>        <validfor>0</validfor>
>      </location>
>    </fileset>
> </junction>
> 
> Note that since the /export/junc referral is stored in a junction, it
> doesn't appear in the export info:
> 
> [root@rawhide ~]# exportfs -v
> /export         <world>(sync,wdelay,hide,no_subtree_check,sec=sys,rw,insecure,no_root_squash,no_all_squash)
> /export/ref     <world>(sync,wdelay,hide,no_subtree_check,refer=/export@192.168.124.66,sec=sys,rw,insecure,no_root_squash,no_all_squash)
> 
>  From the client's standpoint, both style referrals work the same:
> 
> root@aion:~# mount 192.168.124.26:/export /mnt/t
> root@aion:~# ls /mnt/t
> junc  ref
> root@aion:~# ls /mnt/t/ref
> file
> root@aion:~# cat /mnt/t/ref/file
> I am on the referral server.
> root@aion:~# grep nfs4 /proc/mounts
> 192.168.124.26:/export /mnt/t nfs4 rw,relatime,vers=4.2,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.26 0 0
> 192.168.124.66:/export /mnt/t/ref nfs4 rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.66 0 0
> root@aion:~# ls /mnt/t/junc
> file
> root@aion:~# cat /mnt/t/junc/file
> I am on the referral server.
> root@aion:~# grep nfs4 /proc/mounts
> 192.168.124.26:/export /mnt/t nfs4 rw,relatime,vers=4.2,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.26 0 0
> 192.168.124.66:/export /mnt/t/ref nfs4 rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.66 0 0
> 192.168.124.66:/export /mnt/t/junc nfs4 rw,relatime,vers=4.2,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.124.1,local_lock=none,addr=192.168.124.66 0 0
> 
> 
> So if you want to get rid of that last #ifdef HAVE_JUNCTION_SUPPORT
> then you have 2 options:
> 
> a) get rid of junctions entirely, leaving users with only the old
> (relatively speaking) method for configuring referrals
> b) force all packagers of nfs-utils to pull in the extra dependencies
> needed to support junctions, which is the exact opposite of what the
> Debian folks are requesting.
> 
> Or you can take the patch and we can continue to have both style
> referrals.
Very good explanation... we should put this on linux-nfs.org on
how to uses both junctions and referrals...

I'll let the distros decide how they want to deal with this.

thanks!

steved.

> 
> -Scott
>>
>> steved.
>>>
>>> Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
>>> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
>>> ---
>>>    support/export/cache.c | 7 -------
>>>    1 file changed, 7 deletions(-)
>>>
>>> diff --git a/support/export/cache.c b/support/export/cache.c
>>> index 6c0a44a3..3a8e57cf 100644
>>> --- a/support/export/cache.c
>>> +++ b/support/export/cache.c
>>> @@ -34,10 +34,7 @@
>>>    #include "pseudoflavors.h"
>>>    #include "xcommon.h"
>>>    #include "reexport.h"
>>> -
>>> -#ifdef HAVE_JUNCTION_SUPPORT
>>>    #include "fsloc.h"
>>> -#endif
>>>    #ifdef USE_BLKID
>>>    #include "blkid/blkid.h"
>>> @@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
>>>    	*dp = d;
>>>    }
>>> -#ifdef HAVE_JUNCTION_SUPPORT
>>>    static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>>>    {
>>>    	struct servers *servers;
>>> @@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>>>    	qword_addint(bp, blen, servers->h_referral);
>>>    	release_replicas(servers);
>>>    }
>>> -#endif
>>>    static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
>>>    {
>>> @@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
>>>    		qword_addint(&bp, &blen, exp->e_anongid);
>>>    		qword_addint(&bp, &blen, fsidnum);
>>> -#ifdef HAVE_JUNCTION_SUPPORT
>>>    		write_fsloc(&bp, &blen, exp);
>>> -#endif
>>>    		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
>>>    		if (exp->e_uuid == NULL || different_fs) {
>>>    			char u[16];
>>
> 

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Chuck Lever III]

> On Dec 2, 2024, at 10:19 PM, Steve Dickson <SteveD@redhat.com> wrote:
> 
> Hey,
> 
> On 12/2/24 3:30 PM, Scott Mayhew wrote:
>> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
>> libexport.a") caused write_fsloc() to be elided when junction support is
>> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
>> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
>> be around actual junction code).
> Why not just take the enable_junction config variable
> out of configure.ac as well?

It's not generally good practice, but I will break up your
sentence below to reply to each bit. There is something to
unpack in each part.


> If we want junctions/referrals (which are the same)
> IMHO...

Junctions and refer= are related, but they aren't
the same. As Scott demonstrated, a junction is a file
system object that stores NFSv4 referral information.
The "refer=" export option stores that information in
/etc/exports.

The common part of these two mechanisms resides in
NFSD, which turns that information into the response
to a GETATTR(fs_locations).


> on all the time...

We want "refer=" on all the time, yes.

Junction support has to be enabled manually. This is
because it depends on libxml2, which not every distro
wants to, or can, pull into its nfs-utils package.

That is in fact exactly how Salvatore is using this
option. The stable version of Debian's nfs-utils
package does not want libxml2, so junction support is
disabled there. But they /do/ want "refer=" support.


> Lets not be able to turn them off at all?

That would be nice, but it's not yet practical for
every distro to enable it.

I am told that Debian unstable's nfs-utils will
enable junction support, and has added the libxml2
dependency successfully.

We will get there eventually.


> Point being... if we are going remove 3 of the 4
> HAVE_JUNCTION_SUPPORT ifdefs... let get ride of
> all of them.


--
Chuck Lever

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Steve Dickson]

Hey!

On 12/3/24 9:28 AM, Chuck Lever III wrote:
> 
> 
>> On Dec 2, 2024, at 10:19 PM, Steve Dickson <SteveD@redhat.com> wrote:
>>
>> Hey,
>>
>> On 12/2/24 3:30 PM, Scott Mayhew wrote:
>>> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
>>> libexport.a") caused write_fsloc() to be elided when junction support is
>>> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
>>> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
>>> be around actual junction code).
>> Why not just take the enable_junction config variable
>> out of configure.ac as well?
> 
> It's not generally good practice, but I will break up your
> sentence below to reply to each bit. There is something to
> unpack in each part.
I agree not being a good practice... But sometimes
config switches out live their usefulness...
Basically that's what I was thinking

> 
> 
>> If we want junctions/referrals (which are the same)
>> IMHO...
> 
> Junctions and refer= are related, but they aren't
> the same. As Scott demonstrated, a junction is a file
> system object that stores NFSv4 referral information.
> The "refer=" export option stores that information in
> /etc/exports.
Is there a point to have both ways?
What is the advantage of one way over the other?

> 
> The common part of these two mechanisms resides in
> NFSD, which turns that information into the response
> to a GETATTR(fs_locations).
Right... both ways use the same protocol.

> 
> 
>> on all the time...
> 
> We want "refer=" on all the time, yes.
Fine.. Scott's patch will be in the coming releases.

> 
> Junction support has to be enabled manually. This is
> because it depends on libxml2, which not every distro
> wants to, or can, pull into its nfs-utils package.
Yeah... libxml2 seems to be an Fedora only thing.

> 
> That is in fact exactly how Salvatore is using this
> option. The stable version of Debian's nfs-utils
> package does not want libxml2, so junction support is
> disabled there. But they /do/ want "refer=" support.
Yeah... The bug has been around for a while
(pre-pandemic ;-) ) so it appears somebody is
starting to use referrals...

> 
> 
>> Lets not be able to turn them off at all?
> 
> That would be nice, but it's not yet practical for
> every distro to enable it.
Understood.

> 
> I am told that Debian unstable's nfs-utils will
> enable junction support, and has added the libxml2
> dependency successfully.
> 
> We will get there eventually.
Patches are welcome! :-)

steved.

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Chuck Lever III]

> On Dec 3, 2024, at 11:02 AM, Steve Dickson <steved@redhat.com> wrote:
> 
> Hey!
> 
> On 12/3/24 9:28 AM, Chuck Lever III wrote:
>>> On Dec 2, 2024, at 10:19 PM, Steve Dickson <SteveD@redhat.com> wrote:
>>> 
>>> Hey,
>>> 
>>> On 12/2/24 3:30 PM, Scott Mayhew wrote:
>>>> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
>>>> libexport.a") caused write_fsloc() to be elided when junction support is
>>>> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
>>>> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
>>>> be around actual junction code).
>>> Why not just take the enable_junction config variable
>>> out of configure.ac as well?
>> It's not generally good practice, but I will break up your
>> sentence below to reply to each bit. There is something to
>> unpack in each part.
> I agree not being a good practice... But sometimes
> config switches out live their usefulness...
> Basically that's what I was thinking

Sometimes. But --enable-junctions is not there yet.


>>> If we want junctions/referrals (which are the same)
>>> IMHO...
>> Junctions and refer= are related, but they aren't
>> the same. As Scott demonstrated, a junction is a file
>> system object that stores NFSv4 referral information.
>> The "refer=" export option stores that information in
>> /etc/exports.
> Is there a point to have both ways?

"refer=" is the classic way of doing this, but was added
only as an experiment, back in the day.

I added junction support as part of the FedFS effort, a
decade ago. At that time, we decided that junctions,
via the nfsref command, would be the "one way".

We have to wait for distros to pick up junction support
before deprecating "refer=" because there are still
active users of "refer=". Debian stable is one of the
distros that is blocking the complete deprecation of
"refer=".

We also want a better mechanism for kernel/user space
interaction to enable full support for IPv6 addresses
and alternate ports in referrals.

So, work in progress. We want to have "one way" but
there are always some road blocks that make it slower
than just toggling a switch.


--
Chuck Lever

Re: [nfs-utils PATCH] exports: Fix referrals when --enable-junction=no

[Steve Dickson]

On 12/2/24 3:30 PM, Scott Mayhew wrote:
> Commit 15dc0bea ("exportd: Moved cache upcalls routines into
> libexport.a") caused write_fsloc() to be elided when junction support is
> disabled.  Get rid of the bogus #ifdef HAVE_JUNCTION_SUPPORT blocks so
> that referrals work again (the only #ifdef HAVE_JUNCTION_SUPPORT should
> be around actual junction code).
> 
> Fixes: 15dc0bea ("exportd: Moved cache upcalls routines into libexport.a")
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Committed (tag: nfs-utils-2-8-2-rc4)

steved.

> ---
>   support/export/cache.c | 7 -------
>   1 file changed, 7 deletions(-)
> 
> diff --git a/support/export/cache.c b/support/export/cache.c
> index 6c0a44a3..3a8e57cf 100644
> --- a/support/export/cache.c
> +++ b/support/export/cache.c
> @@ -34,10 +34,7 @@
>   #include "pseudoflavors.h"
>   #include "xcommon.h"
>   #include "reexport.h"
> -
> -#ifdef HAVE_JUNCTION_SUPPORT
>   #include "fsloc.h"
> -#endif
>   
>   #ifdef USE_BLKID
>   #include "blkid/blkid.h"
> @@ -999,7 +996,6 @@ static void nfsd_retry_fh(struct delayed *d)
>   	*dp = d;
>   }
>   
> -#ifdef HAVE_JUNCTION_SUPPORT
>   static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>   {
>   	struct servers *servers;
> @@ -1022,7 +1018,6 @@ static void write_fsloc(char **bp, int *blen, struct exportent *ep)
>   	qword_addint(bp, blen, servers->h_referral);
>   	release_replicas(servers);
>   }
> -#endif
>   
>   static void write_secinfo(char **bp, int *blen, struct exportent *ep, int flag_mask, int extra_flag)
>   {
> @@ -1120,9 +1115,7 @@ static int dump_to_cache(int f, char *buf, int blen, char *domain,
>   		qword_addint(&bp, &blen, exp->e_anongid);
>   		qword_addint(&bp, &blen, fsidnum);
>   
> -#ifdef HAVE_JUNCTION_SUPPORT
>   		write_fsloc(&bp, &blen, exp);
> -#endif
>   		write_secinfo(&bp, &blen, exp, flag_mask, do_fsidnum ? NFSEXP_FSID : 0);
>   		if (exp->e_uuid == NULL || different_fs) {
>   			char u[16];