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 Thu, Jan 02, 2014 at 05:26:51PM -0500, Jeff Layton 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).
> > 
> 
> What wasn't clear to me is what would be doing this read.
> 
> I'll take it from your comment then that patch #1 is acceptable?

Yes.  Thanks!

> > 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.
> > 
> 
> I'll let Simo confirm that that's what gssproxy does, but yes that is
> the desired behavior. Typically this is done by ensuring that the parent
> process when daemon()-izing doesn't exit until everything is ready.
> 
> If gssproxy does need to be changed for that, we have a library routine
> now in nfs-utils that does this that you can likely copy (see
> mydaemon()).

>From a quick skim: looks like gss-proxy does this in init_server().  So
I think it might need something like the below?

(Untested.  I spent a total of maybe five minutes looking at this code
so have no idea what I'm doing.)

--b.

diff --git a/proxy/src/gssproxy.c b/proxy/src/gssproxy.c
index 1fca922..a7cbd7c 100644
--- a/proxy/src/gssproxy.c
+++ b/proxy/src/gssproxy.c
@@ -97,6 +97,12 @@ int main(int argc, const char *argv[])
         exit(EXIT_FAILURE);
     }
 
+    /*
+     * special call to tell the Linux kernel gss-proxy is available.
+     * Note this must be done before nfsd is started.
+     */
+    init_proc_nfsd(gpctx->config);
+
     init_server(gpctx->config->daemonize);
 
     write_pid();
@@ -139,9 +145,6 @@ int main(int argc, const char *argv[])
         }
     }
 
-    /* special call to tell the Linux kernel gss-proxy is available */
-    init_proc_nfsd(gpctx->config);
-
     ret = gp_workers_init(gpctx);
     if (ret) {
         exit(EXIT_FAILURE);