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Date: Fri, 26 Jun 2015 13:58:35 -0400
Message-ID: <CAHQdGtSS7+Vu4fS9_-UkkoE7AcjsAC8HSqT=LhT32A-kc5UnOA@mail.gmail.com>
Subject: Re: Mount regression between 4.0.4 client and 2.6.35 server
From: Trond Myklebust <trond.myklebust@primarydata.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Benjamin Coddington <bcodding@redhat.com>,
        Anders Blomdell <anders.blomdell@control.lth.se>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
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On Fri, Jun 26, 2015 at 1:50 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> On Fri, Jun 26, 2015 at 08:17:30AM -0400, Benjamin Coddington wrote:
>> On Thu, 18 Jun 2015, Trond Myklebust wrote:
>>
>> > On Thu, Jun 18, 2015 at 4:04 AM, Anders Blomdell
>> > <anders.blomdell@control.lth.se> wrote:
>> > >
>> > > I have a problem with a 4.0.4 client refusing to mount from a 2.6.35 server
>> > > due to NFS4ERR_INVAL returned during nfs4_discover_server_trunking. See
>> > > https://bugzilla.redhat.com/show_bug.cgi?id=1228272.
>> >
>> >
>> > Why should we change the clients if the server is in clear and obvious
>> > violation of the spec?
>>
>>
>> What's happening here is knfsd older than 2.6.38 will return NFS4ERR_INVAL
>> for EXCHANGE_ID that has EXCHGID4_FLAG_BIND_PRINC_STATEID set in the
>> request.
>
> Note that intentionally left off by default until 3.11, exactly because
> I thought there was a high risk of incompatibility with future clients
> at that point.
>
>> Should the client's use of stateid/princ binding be optional/configureable?
>
> So, perhaps there's other reasons for doing this, but we're not going to
> justify it for compatibility with out-of-spec behavior in older
> experimental server code.

The protocol gives the server the option of rejecting the client's
request for bind_princ_stateid by simply turning off the flag in its
reply. See https://tools.ietf.org/html/rfc5661#section-18.35.3

> Possibly more annoying is that Solaris servers (I don't know which
> versions, I just have one report that says "Solaris 10") are also
> returning GARBAGE_ARGS instead of NFS4ERR_MINOR_VERS_MISMATCH on
> attempts to use 4.2.