Subject: Re: [RFC PATCH 1/5] sunrpc: don't wait for write before allowing
 reads from use-gss-proxy file
From: Simo Sorce <simo@redhat.com>
To: Jeff Layton <jlayton@redhat.com>
Cc: NeilBrown <neilb@suse.de>, "J. Bruce Fields" <bfields@fieldses.org>,
        linux-nfs@vger.kernel.org
In-Reply-To: <20140105204516.51aa31ad@corrin.poochiereds.net>
References: <1388579314-15255-1-git-send-email-jlayton@redhat.com>
	 <1388579314-15255-2-git-send-email-jlayton@redhat.com>
	 <20140102212149.GC28219@fieldses.org>
	 <20140106093744.14fc3670@notabene.brown>
	 <20140105204516.51aa31ad@corrin.poochiereds.net>
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Date: Mon, 06 Jan 2014 01:36:13 -0500
Message-ID: <1388990173.26102.69.camel@willson.li.ssimo.org>
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Sender: linux-nfs-owner@vger.kernel.org

On Sun, 2014-01-05 at 20:45 -0500, Jeff Layton wrote:
> On Mon, 6 Jan 2014 09:37:44 +1100
> NeilBrown <neilb@suse.de> wrote:
> 
> > On Thu, 2 Jan 2014 16:21:50 -0500 "J. Bruce Fields" <bfields@fieldses.org>
> > wrote:
> > 
> > > On Wed, Jan 01, 2014 at 07:28:30AM -0500, Jeff Layton wrote:
> > > > It doesn't make much sense to make reads from this procfile hang. As
> > > > far as I can tell, only gssproxy itself will open this file and it
> > > > never reads from it. Change it to just give the present setting of
> > > > sn->use_gss_proxy without waiting for anything.
> > > 
> > > I think my *only* reason for doing this was to give a simple way to wait
> > > for gss-proxy to start (just wait for a read to return).
> > > 
> > > As long as gss-proxy has some way to say "I'm up and running", and as
> > > long as that comes after writing to use-gss-proxy, we're fine.
> > > 
> > 
> > 
> > Only tangentially related to the above email .....
> > 
> > I had a look at this new-fangled gssproxy thing and while it mostly seems
> > like a good idea, I find the hard-coding of "/var/run/gssproxy.sock" in the
> > kernel source .... disturbing.
> > You never know when some user-space might want to change that - maybe to
> > "/run/gssproxy.sock" (unlikely I know - but possible).
> > 
> > Probably the easiest would be to hand the path to the kernel.
> > 
> > e.g. instead  of writing '1' to "use-gss-proxy", we could 
> >   echo /my/path/gss-proxy-sock > /proc/net/rpc/use-gss-proxy
> > 
> > Then you could even use an 'abstract' socket name if you wanted. i.e. one
> > starting with a nul and which doesn't exist anywhere in the filesystem.
> > I would feel a lot more comfortable with that than with the current
> > hard-coding.
> > 
> 
> I like that idea -- particularly if you keep the legacy behavior that
> writing a '1' to the file makes it default to /var/run/gssproxy.sock so
> we don't break compatability with older gssproxy releases.

I have no problem adding this to gss-proxy but I wonder if it is really
that important.

In what case gss-proxy will not be able to create a file
named /var/run/gssproxy.sock ? The only case would be for the distro to
outlaw creating a path named /var/run, note that /var/run does not need
to be the same as /run for gssproxy to be able to create a socket.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York