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From:   "Frank Filz" <ffilzlnx@mindspring.com>
To:     "'J. Bruce Fields'" <bfields@fieldses.org>,
        "'Jeff Layton'" <jlayton@kernel.org>
Cc:     <steved@redhat.com>, <linux-nfs@vger.kernel.org>,
        <jfajerski@suse.com>
References: <20190510215445.1823-1-jlayton@kernel.org> <20190511135442.GA15721@fieldses.org> <593884facebf2ebcafcbe577845a961abbaa9928.camel@kernel.org> <20190513134457.GA13359@fieldses.org>
In-Reply-To: <20190513134457.GA13359@fieldses.org>
Subject: RE: [PATCH] manpage: explain why showmount doesn't really work against a v4-only server
Date:   Mon, 13 May 2019 07:19:57 -0700
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> On Mon, May 13, 2019 at 09:29:42AM -0400, Jeff Layton wrote:
> > Yeah, that certainly wouldn't hurt. I'd suggest we add that in a
> > separate patch though.
> 
> Agreed.
> 
> > We will need to spell this out in the manpage either way. At least
> > with ganesha, you can export some filesystems via v3 and others via v4
> > only, and the MNT service there will only report the v3 ones. In that
> > case, you have a reachable service, but the v4-only filesystems will
> > be missing from showmount's output.
> 
> That doesn't sound like a great idea to me, but maybe you have no choice
if for
> some reason you want to allow simultaneous support for v3-only clients and
for
> filesystems that require long filehandles?  Ugh.
> 
> Anyway, this kind of warning doesn't have to catch every odd case.

Good conversation.

Another thing worth noting in the warning also is that some servers (Ganesha
for sure) will not list exports to showmount that the client issuing the
showmount doesn't have access to (and for NFSv4 they won't show up in the
directory listing).

Obviously the warning can't be perfect, but at least highlighting that the
issue of what exports are visible is complicated.

Frank