[PATCH] knfsd: Correctly handle error condition from lockd_up

If lockd_up fails - what should we expect?  Do we have to later call
lockd_down?

Well the nfs client thinks "no", the nfs server thinks "yes".  lockd thinks
"yes".

The only answer that really makes sense is "no" !!

So:
  Make lockd_up only increment  nlmsvc_users on success.
  Make nfsd handle errors from lockd_up properly.
  Make sure lockd_up(0) never fails when lockd is running
    so that the 'reclaimer' call to lockd_up doesn't need to
    be error checked.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/lockd/clntlock.c

@@ -202,7 +202,7 @@ reclaimer(void *ptr)
 	/* This one ensures that our parent doesn't terminate while the
 	 * reclaim is in progress */
 	lock_kernel();
-	lockd_up(0);
+	lockd_up(0); /* note: this cannot fail as lockd is already running */
 
 	nlmclnt_prepare_reclaim(host);
 	/* First, reclaim all locks that have been marked. */

fs/lockd/svc.c

@@ -253,16 +253,12 @@ lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 	int			error = 0;
 
 	mutex_lock(&nlmsvc_mutex);
-	/*
-	 * Unconditionally increment the user count ... this is
-	 * the number of clients who _want_ a lockd process.
-	 */
-	nlmsvc_users++; 
 	/*
 	 * Check whether we're already up and running.
 	 */
 	if (nlmsvc_pid) {
-		error = make_socks(nlmsvc_serv, proto);
+		if (proto)
+			error = make_socks(nlmsvc_serv, proto);
 		goto out;
 	}
 
@@ -270,7 +266,7 @@ lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 	 * Sanity check: if there's no pid,
 	 * we should be the first user ...
 	 */
-	if (nlmsvc_users > 1)
+	if (nlmsvc_users)
 		printk(KERN_WARNING
 			"lockd_up: no pid, %d users??\n", nlmsvc_users);
 
@@ -302,6 +298,8 @@ lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 destroy_and_out:
 	svc_destroy(serv);
 out:
+	if (!error)
+		nlmsvc_users++;
 	mutex_unlock(&nlmsvc_mutex);
 	return error;
 }

fs/nfsd/nfssvc.c

@@ -221,18 +221,22 @@ static int nfsd_init_socks(int port)
 	if (!list_empty(&nfsd_serv->sv_permsocks))
 		return 0;
 
-	error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
-	if (error < 0)
-		return error;
 	error = lockd_up(IPPROTO_UDP);
+	if (error >= 0) {
+		error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
+		if (error < 0)
+			lockd_down();
+	}
 	if (error < 0)
 		return error;
 
 #ifdef CONFIG_NFSD_TCP
-	error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
-	if (error < 0)
-		return error;
 	error = lockd_up(IPPROTO_TCP);
+	if (error >= 0) {
+		error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
+		if (error < 0)
+			lockd_down();
+	}
 	if (error < 0)
 		return error;
 #endif