Re: [RFC] new client gssd upcall

[Trond Myklebust <Trond.Myklebust@netapp.com>]

On Tue, 2008-06-17 at 17:36 -0400, J. Bruce Fields wrote:
> On Mon, Jun 16, 2008 at 10:28:59AM -0400, Jeff Layton wrote:
> > On Fri, 13 Jun 2008 18:50:37 -0400
> > "J. Bruce Fields" <bfields@citi.umich.edu> wrote:
> > 
> > > The client needs a new more estensible text-based upcall to gssd, to
> > > make it easier to support some features that are needed for new krb5
> > > enctypes, for callbacks, etc.
> > > 
> > > We will have to continue to support the old upcall for backwards
> > > compatibility with older gssd's.  To simplify upgrades, as well as
> > > testing and debugging, it would help if we can upgrade gssd without
> > > having to choose at boot (or module-load) time whether we want the new
> > > or the old upcall.
> > > 
> > > That means that when gssd opens an rpc upcall pipe, we'd like to just
> > > start using whichever version it chose immediately--ideally without
> > > having to wait the 30 seconds that it would normally take for upcalls
> > > already queued on the wrong upcall pipe to time out.
> > > 
> > > The following patches do that by queueing the upcalls on whichever of
> > > the two upcall pipes (the new one and the old one) that somebody holds
> > > open.  If nobody's opened anything yet, then upcalls are provisionally
> > > queued on the new pipe.  I add a pipe_open method to allow the gss code
> > > to keep track of which pipe is open, to prevent anyone from attempting
> > > to open both pipes at once, and to cancel any upcalls that got queued to
> > > the wrong pipe.
> > > 
> > > I did some minimal testing with the old upcall, but haven't tested the
> > > new upcall yet.  (Olga, could you do that?)  So this is just an RFC at
> > > this point.
> > > 
> > > --b.
> > 
> > Has any thought been given to moving all of the rpc_pipefs upcalls to use
> > the keyctl API that David Howells did? It seems like that would be better
> > suited to this sort of application than rpc_pipefs...
> 
> I haven't looked at it.  I've just assumed that since Trond and Kevin
> have both looked at both API's, then there must be some good reason
> we're not using it....

Kevin has spent quite some time working on the keyring support, but as
far as I understand the amount of time he can continue to spend working
for CITI has recently been heavily reduced...

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com