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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Steve Dickson <steved@redhat.com>
CC:     Richard Weinberger <richard@nod.at>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        david <david@sigma-star.at>, Bruce Fields <bfields@fieldses.org>,
        "luis.turcitu@appsbroker.com" <luis.turcitu@appsbroker.com>,
        "david.young@appsbroker.com" <david.young@appsbroker.com>,
        "david.oberhollenzer@sigma-star.at" 
        <david.oberhollenzer@sigma-star.at>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        "chris.chilvers@appsbroker.com" <chris.chilvers@appsbroker.com>
Subject: Re: [PATCH 1/5] Implement reexport helper library
Thread-Topic: [PATCH 1/5] Implement reexport helper library
Thread-Index: AQHYXgHgoneWG2g3iEC82B/y61YHaq0YKM4AgAAEiICAAARAAIAAA7gAgABh+QCAAAhdAA==
Date:   Tue, 10 May 2022 20:37:56 +0000
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> On May 10, 2022, at 4:08 PM, Steve Dickson <steved@redhat.com> wrote:
>=20
> On 5/10/22 10:17 AM, Chuck Lever III wrote:
>>> On May 10, 2022, at 10:04 AM, Steve Dickson <steved@redhat.com> wrote:
>>>=20
>>> Hey!
>>>=20
>>> On 5/10/22 9:48 AM, Chuck Lever III wrote:
>>>>> On May 10, 2022, at 9:32 AM, Steve Dickson <steved@redhat.com> wrote:
>>>>>=20
>>>>> Hello,
>>>>>=20
>>>>> On 5/2/22 4:50 AM, Richard Weinberger wrote:
>>>>>> This internal library contains code that will be used by various
>>>>>> tools within the nfs-utils package to deal better with NFS re-export=
,
>>>>>> especially cross mounts.
>>>>>> Signed-off-by: Richard Weinberger <richard@nod.at>
>>>>>> ---
>>>>>>  configure.ac                 |  12 ++
>>>>>>  support/Makefile.am          |   4 +
>>>>>>  support/reexport/Makefile.am |   6 +
>>>>>>  support/reexport/reexport.c  | 285 ++++++++++++++++++++++++++++++++=
+++
>>>>>>  support/reexport/reexport.h  |  39 +++++
>>>>>>  5 files changed, 346 insertions(+)
>>>>>>  create mode 100644 support/reexport/Makefile.am
>>>>>>  create mode 100644 support/reexport/reexport.c
>>>>>>  create mode 100644 support/reexport/reexport.h
>>>>>> diff --git a/configure.ac b/configure.ac
>>>>>> index 93626d62..86bf8ba9 100644
>>>>>> --- a/configure.ac
>>>>>> +++ b/configure.ac
>>>>>> @@ -274,6 +274,17 @@ AC_ARG_ENABLE(nfsv4server,
>>>>>>  	fi
>>>>>>  	AM_CONDITIONAL(CONFIG_NFSV4SERVER, [test "$enable_nfsv4server" =3D=
 "yes" ])
>>>>>>  +AC_ARG_ENABLE(reexport,
>>>>>> +	[AC_HELP_STRING([--enable-reexport],
>>>>>> +			[enable support for re-exporting NFS mounts  @<:@default=3Dno@:>=
@])],
>>>>>> +	enable_reexport=3D$enableval,
>>>>>> +	enable_reexport=3D"no")
>>>>>> +	if test "$enable_reexport" =3D yes; then
>>>>>> +		AC_DEFINE(HAVE_REEXPORT_SUPPORT, 1,
>>>>>> +                          [Define this if you want NFS re-export su=
pport compiled in])
>>>>>> +	fi
>>>>>> +	AM_CONDITIONAL(CONFIG_REEXPORT, [test "$enable_reexport" =3D "yes"=
 ])
>>>>>> +
>>>>> To get this moving I'm going to add a --disable-reexport flag
>>>> Hi Steve, no-one has given a reason why disabling support
>>>> for re-exports would be necessary. Therefore, can't this
>>>> switch just be removed?
>>> The precedence has been that we used --disable-XXX flag
>>> a lot in configure.ac... -nfsv4, -nfsv41, etc...
>>> I'm just following along with that.
>> I get that... but no-one has given a technical reason
>> why disabling this code would even be necessary.
> Nobody has see the code yet... :-)
>=20
> There is a lot of churn in these patch.
>=20
>>> Yes, at this point, nobody is asking to turn it off but
>>> in future somebody may want to... due some security hole
>>> or just make the footprint of the package smaller.
>> I'll bite. What is the added footprint of this patch
>> series? I didn't think there was a new library dependency
>> or anything like that...
> Well mountd is now using an database and there
> is a static reexport lib that a number daemons
> and command like with...

nfs-utils already depends on sqlite for the nfsd
cltrack stuff, so I don't really see an additional
dependency for nfs-utils there.

However, there is a configure.ac switch that says
if there's no sqlite in the build environment,
then nfsdcltrack is entirely disabled. I guess
the build environment needs to deal correctly
with that situation and re-export support.


--
Chuck Lever