Re: [RFC PATCH 1/5] sunrpc: don't wait for write before allowing reads from use-gss-proxy file

["J. Bruce Fields" <bfields@fieldses.org>]

On Mon, Jan 06, 2014 at 01:36:13AM -0500, Simo Sorce wrote:
> 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.

Well, I suppose we could fix the hard-coded kernel paths but still leave
it hard-coded in gss-proxy until someone demonstrated a need for it to
be configurable.

I like the principle but don't see this as a very high priority.

--b.