From: NeilBrown <neilb@suse.com>
To: Trond Myklebust <trondmy@primarydata.com>,
        "jlayton\@poochiereds.net" <jlayton@poochiereds.net>,
        "linux-nfs\@vger.kernel.org" <linux-nfs@vger.kernel.org>
Date: Wed, 08 Mar 2017 07:09:26 +1100
Cc: "hch\@infradead.org" <hch@infradead.org>
Subject: Re: Confused by pnfs LAYOUTRETURN - seeking clarity.
In-Reply-To: <1488847700.2913.1.camel@primarydata.com>
References: <87shmvnzh7.fsf@notabene.neil.brown.name> <1488569105.2997.1.camel@poochiereds.net> <87r32bjbzq.fsf@notabene.neil.brown.name> <1488847700.2913.1.camel@primarydata.com>
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On Tue, Mar 07 2017, Trond Myklebust wrote:

> Hi Neil,
>
> On Mon, 2017-03-06 at 14:54 +1100, NeilBrown wrote:
...
>>=20
>> So the Netapp filer is clearly doing the wrong thing, as we doesn't
>> send
>> CB_LAYOUTRECALL.=C2=A0=C2=A0But I'm far from convinced that Linux is doi=
ng the
>> right thing by replying NFS4ERR_NOMATCHING_LAYOUT.
>>=20
>> However, I'm not going to try to "fix" anything here.=C2=A0=C2=A0Hopeful=
ly we
>> can
>> manage to stumble forward.
>>=20
>
> Please see RFC5661, Section 12.5.5.1 https://tools.ietf.org/html/rfc566
> 1#section-12.5.5.1
>
> That section has a full documentation of what the server should
> interpret NFS4ERR_NOMATCHING_LAYOUT to mean, and should explain why the
> Linux client behaviour is quite correct w.r.t. the spec.
> There are a couple of errata to consider too, but they mainly try to
> nail down the expected behaviour for a couple of corner cases.

Thanks for that.  The last too sentences to suggest that
NFS4ERR_NOMATCHING_LAYOUT isn't really an error, and the whole
discusses how the server and client can reasonably have different
understandings of the current set of layouts.

Thanks,
NeilBrown

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