[PATCH] knfsd: be more selective in which sockets lockd listens on

Currently lockd listens on UDP always, and TCP if CONFIG_NFSD_TCP is set.

However as lockd performs services of the client as well, this is a problem.
If CONFIG_NfSD_TCP is not set, and a tcp mount is used, the server will not be
able to call back to lockd.

So:
 - add an option to lockd_up saying which protocol is needed
 - Always open sockets for which an explicit port was given, otherwise
   only open a socket of the type required
 - Change nfsd to do one lockd_up per socket rather than one per thread.

This
 - removes the dependancy on CONFIG_NFSD_TCP
 - means that lockd may open sockets other than at startup
 - means that lockd will *not* listen on UDP if the only
   mounts are TCP mount (and nfsd hasn't started).

The latter is the only one that concerns me at all - I don't know if this
might be a problem with some servers.

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();
+	lockd_up(0);
 
 	nlmclnt_prepare_reclaim(host);
 	/* First, reclaim all locks that have been marked. */

fs/lockd/svc.c

@@ -31,6 +31,7 @@
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/svc.h>
 #include <linux/sunrpc/svcsock.h>
+#include <net/ip.h>
 #include <linux/lockd/lockd.h>
 #include <linux/nfs.h>
 
@@ -46,6 +47,7 @@ EXPORT_SYMBOL(nlmsvc_ops);
 static DEFINE_MUTEX(nlmsvc_mutex);
 static unsigned int		nlmsvc_users;
 static pid_t			nlmsvc_pid;
+static struct svc_serv		*nlmsvc_serv;
 int				nlmsvc_grace_period;
 unsigned long			nlmsvc_timeout;
 
@@ -112,6 +114,7 @@ lockd(struct svc_rqst *rqstp)
 	 * Let our maker know we're running.
 	 */
 	nlmsvc_pid = current->pid;
+	nlmsvc_serv = serv;
 	complete(&lockd_start_done);
 
 	daemonize("lockd");
@@ -189,6 +192,7 @@ lockd(struct svc_rqst *rqstp)
 			nlmsvc_invalidate_all();
 		nlm_shutdown_hosts();
 		nlmsvc_pid = 0;
+		nlmsvc_serv = NULL;
 	} else
 		printk(KERN_DEBUG
 			"lockd: new process, skipping host shutdown\n");
@@ -205,11 +209,42 @@ lockd(struct svc_rqst *rqstp)
 	module_put_and_exit(0);
 }
 
+
+static int find_socket(struct svc_serv *serv, int proto)
+{
+	struct svc_sock *svsk;
+	int found = 0;
+	list_for_each_entry(svsk, &serv->sv_permsocks, sk_list)
+		if (svsk->sk_sk->sk_protocol == proto) {
+			found = 1;
+			break;
+		}
+	return found;
+}
+
+static int make_socks(struct svc_serv *serv, int proto)
+{
+	/* Make any sockets that are needed but not present.
+	 * If nlm_udpport or nlm_tcpport were set as module
+	 * options, make those sockets unconditionally
+	 */
+	int err = 0;
+	if (proto == IPPROTO_UDP || nlm_udpport)
+		if (!find_socket(serv, IPPROTO_UDP))
+			err = svc_makesock(serv, IPPROTO_UDP, nlm_udpport);
+	if (err)
+		return err;
+	if (proto == IPPROTO_TCP || nlm_tcpport)
+		if (!find_socket(serv, IPPROTO_TCP))
+			err= svc_makesock(serv, IPPROTO_TCP, nlm_tcpport);
+	return err;
+}
+
 /*
  * Bring up the lockd process if it's not already up.
  */
 int
-lockd_up(void)
+lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 {
 	static int		warned;
 	struct svc_serv *	serv;
@@ -224,8 +259,10 @@ lockd_up(void)
 	/*
 	 * Check whether we're already up and running.
 	 */
-	if (nlmsvc_pid)
+	if (nlmsvc_pid) {
+		error = make_socks(nlmsvc_serv, proto);
 		goto out;
+	}
 
 	/*
 	 * Sanity check: if there's no pid,
@@ -242,11 +279,7 @@ lockd_up(void)
 		goto out;
 	}
 
-	if ((error = svc_makesock(serv, IPPROTO_UDP, nlm_udpport)) < 0 
+	if ((error = make_socks(serv, proto)) < 0) {
-#ifdef CONFIG_NFSD_TCP
-	 || (error = svc_makesock(serv, IPPROTO_TCP, nlm_tcpport)) < 0
-#endif
-		) {
 		if (warned++ == 0) 
 			printk(KERN_WARNING
 				"lockd_up: makesock failed, error=%d\n", error);

fs/nfs/client.c

@@ -460,7 +460,8 @@ static int nfs_start_lockd(struct nfs_server *server)
 		goto out;
 	if (server->flags & NFS_MOUNT_NONLM)
 		goto out;
-	error = lockd_up();
+	error = lockd_up((server->flags & NFS_MOUNT_TCP) ?
+			IPPROTO_TCP : IPPROTO_UDP);
 	if (error < 0)
 		server->flags |= NFS_MOUNT_NONLM;
 	else

fs/nfsd/nfssvc.c

@@ -134,6 +134,9 @@ static int killsig;	/* signal that was used to kill last nfsd */
 static void nfsd_last_thread(struct svc_serv *serv)
 {
 	/* When last nfsd thread exits we need to do some clean-up */
+	struct svc_sock *svsk;
+	list_for_each_entry(svsk, &serv->sv_permsocks, sk_list)
+		lockd_down();
 	nfsd_serv = NULL;
 	nfsd_racache_shutdown();
 	nfs4_state_shutdown();
@@ -218,11 +221,16 @@ nfsd_svc(unsigned short port, int nrservs)
 		error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
 		if (error < 0)
 			goto failure;
-
+		error = lockd_up(IPPROTO_UDP);
+		if (error < 0)
+			goto failure;
 #ifdef CONFIG_NFSD_TCP
 		error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
 		if (error < 0)
 			goto failure;
+		error = lockd_up(IPPROTO_TCP);
+		if (error < 0)
+			goto failure;
 #endif
 		do_gettimeofday(&nfssvc_boot);		/* record boot time */
 	} else
@@ -306,8 +314,6 @@ nfsd(struct svc_rqst *rqstp)
 
 	nfsdstats.th_cnt++;
 
-	lockd_up();				/* start lockd */
-
 	me.task = current;
 	list_add(&me.list, &nfsd_list);
 
@@ -364,13 +370,11 @@ nfsd(struct svc_rqst *rqstp)
 				break;
 		killsig = signo;
 	}
-	/* Clear signals before calling lockd_down() and svc_exit_thread() */
+	/* Clear signals before calling svc_exit_thread() */
 	flush_signals(current);
 
 	lock_kernel();
 
-	/* Release lockd */
-	lockd_down();
 	list_del(&me.list);
 	nfsdstats.th_cnt --;
 

include/linux/lockd/bind.h

@@ -30,7 +30,7 @@ extern struct nlmsvc_binding *	nlmsvc_ops;
  * Functions exported by the lockd module
  */
 extern int	nlmclnt_proc(struct inode *, int, struct file_lock *);
-extern int	lockd_up(void);
+extern int	lockd_up(int proto);
 extern void	lockd_down(void);
 
 #endif /* LINUX_LOCKD_BIND_H */