NFS: convert proto= option to use netids rather than a protoname

Solaris uses netids as values for the proto= option, so that when
someone specifies "tcp6" they get traffic over TCP + IPv6. Until
recently, this has never really been an issue for Linux since it didn't
support NFS over IPv6. The netid and the protocol name were generally
always the same (modulo any strange configuration in /etc/netconfig).

The solaris manpage documents their proto= option as:

    proto= _netid_ | rdma

This patch is intended to bring Linux closer to how the Solaris proto=
option works, by declaring a static netid mapping in the kernel and
converting the proto= and mountproto= options to follow it and display
the proper values in /proc/mounts.

Much of this functionality will need to be provided by a userspace
mount.nfs patch. Chuck Lever has a patch to change mount.nfs in
the same way. In principle, we could do *all* of this in userspace but
that would mean that the options in /proc/mounts may not match the
options used by userspace.

The alternative to the static mapping here is to add a mechanism to
upcall to userspace for netid's. I'm not opposed to that option, but
it'll probably mean more overhead (and quite a bit more code). Rather
than shoot for that at first, I figured it was probably better to
start simply.

Comments welcome.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/super.c

@@ -175,14 +175,16 @@ static const match_table_t nfs_mount_option_tokens = {
 };
 
 enum {
-	Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
+	Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
 
 	Opt_xprt_err
 };
 
 static const match_table_t nfs_xprt_protocol_tokens = {
 	{ Opt_xprt_udp, "udp" },
+	{ Opt_xprt_udp6, "udp6" },
 	{ Opt_xprt_tcp, "tcp" },
+	{ Opt_xprt_tcp6, "tcp6" },
 	{ Opt_xprt_rdma, "rdma" },
 
 	{ Opt_xprt_err, NULL }
@@ -492,6 +494,45 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 	return sec_flavours[i].str;
 }
 
+static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
+				  int showdefaults)
+{
+	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
+
+	seq_printf(m, ",mountproto=");
+	switch (sap->sa_family) {
+	case AF_INET:
+		switch (nfss->mountd_protocol) {
+		case IPPROTO_UDP:
+			seq_printf(m, RPCBIND_NETID_UDP);
+			break;
+		case IPPROTO_TCP:
+			seq_printf(m, RPCBIND_NETID_TCP);
+			break;
+		default:
+			if (showdefaults)
+				seq_printf(m, "auto");
+		}
+		break;
+	case AF_INET6:
+		switch (nfss->mountd_protocol) {
+		case IPPROTO_UDP:
+			seq_printf(m, RPCBIND_NETID_UDP6);
+			break;
+		case IPPROTO_TCP:
+			seq_printf(m, RPCBIND_NETID_TCP6);
+			break;
+		default:
+			if (showdefaults)
+				seq_printf(m, "auto");
+		}
+		break;
+	default:
+		if (showdefaults)
+			seq_printf(m, "auto");
+	}
+}
+
 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
 				    int showdefaults)
 {
@@ -518,17 +559,7 @@ static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
 	if (nfss->mountd_port || showdefaults)
 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
 
-	switch (nfss->mountd_protocol) {
-	case IPPROTO_UDP:
-		seq_printf(m, ",mountproto=udp");
-		break;
-	case IPPROTO_TCP:
-		seq_printf(m, ",mountproto=tcp");
-		break;
-	default:
-		if (showdefaults)
-			seq_printf(m, ",mountproto=auto");
-	}
+	nfs_show_mountd_netid(m, nfss, showdefaults);
 }
 
 /*
@@ -578,7 +609,7 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
 			seq_puts(m, nfs_infop->nostr);
 	}
 	seq_printf(m, ",proto=%s",
-		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
+		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
 	if (version == 4) {
 		if (nfss->port != NFS_PORT)
 			seq_printf(m, ",port=%u", nfss->port);
@@ -883,6 +914,8 @@ static int nfs_parse_mount_options(char *raw,
 {
 	char *p, *string, *secdata;
 	int rc, sloppy = 0, invalid_option = 0;
+	unsigned short protofamily = AF_UNSPEC;
+	unsigned short mountfamily = AF_UNSPEC;
 
 	if (!raw) {
 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
@@ -1228,12 +1261,17 @@ static int nfs_parse_mount_options(char *raw,
 			token = match_token(string,
 					    nfs_xprt_protocol_tokens, args);
 
+			protofamily = AF_INET;
 			switch (token) {
+			case Opt_xprt_udp6:
+				protofamily = AF_INET6;
 			case Opt_xprt_udp:
 				mnt->flags &= ~NFS_MOUNT_TCP;
 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 				kfree(string);
 				break;
+			case Opt_xprt_tcp6:
+				protofamily = AF_INET6;
 			case Opt_xprt_tcp:
 				mnt->flags |= NFS_MOUNT_TCP;
 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
@@ -1261,10 +1299,15 @@ static int nfs_parse_mount_options(char *raw,
 					    nfs_xprt_protocol_tokens, args);
 			kfree(string);
 
+			mountfamily = AF_INET;
 			switch (token) {
+			case Opt_xprt_udp6:
+				mountfamily = AF_INET6;
 			case Opt_xprt_udp:
 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 				break;
+			case Opt_xprt_tcp6:
+				mountfamily = AF_INET6;
 			case Opt_xprt_tcp:
 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 				break;
@@ -1363,8 +1406,33 @@ static int nfs_parse_mount_options(char *raw,
 	if (!sloppy && invalid_option)
 		return 0;
 
+	/*
+	 * verify that any proto=/mountproto= options match the address
+	 * familiies in the addr=/mountaddr= options.
+	 */
+	if (protofamily != AF_UNSPEC &&
+	    protofamily != mnt->nfs_server.address.ss_family)
+		goto out_proto_mismatch;
+
+	if (mountfamily != AF_UNSPEC) {
+		if (mnt->mount_server.addrlen) {
+			if (mountfamily != mnt->mount_server.address.ss_family)
+				goto out_mountproto_mismatch;
+		} else {
+			if (mountfamily != mnt->nfs_server.address.ss_family)
+				goto out_mountproto_mismatch;
+		}
+	}
+
 	return 1;
 
+out_mountproto_mismatch:
+	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
+			 "option\n");
+	return 0;
+out_proto_mismatch:
+	printk(KERN_INFO "NFS: server address does not match proto= option\n");
+	return 0;
 out_invalid_address:
 	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
 	return 0;