util-linux/util-linux-2.12-mount_nfs_tcp.patch

Index: util-linux-ng-2.12r+2.13pre7/mount/nfs.5
===================================================================
--- util-linux-ng-2.12r+2.13pre7.orig/mount/nfs.5
+++ util-linux-ng-2.12r+2.13pre7/mount/nfs.5
@@ -199,11 +199,11 @@ writing to common filesystem on the serv
 .TP 1.5i
 .I tcp
 Mount the NFS filesystem using the TCP protocol instead of the
-default UDP protocol.  Many NFS servers only support UDP.
+UDP protocol. This is the default, but in case it fails (many NFS servers only
+support UDP) it will fallback and try UDP.
 .TP 1.5i
 .I udp
-Mount the NFS filesystem using the UDP protocol.  This
-is the default.
+Mount the NFS filesystem using the UDP protocol.
 .TP 1.5i
 .I noacl
 Assume no extended access control mechanisms like POSIX ACLs are used
@@ -227,8 +227,5 @@ interrupted.
 The posix, and nocto options are parsed by mount
 but currently are silently ignored.
 .P
-The tcp and namlen options are implemented but are not currently
-supported by the Linux kernel.
-.P
 The umount command should notify the server
 when an NFS filesystem is unmounted.
Index: util-linux-ng-2.12r+2.13pre7/mount/nfsmount.c
===================================================================
--- util-linux-ng-2.12r+2.13pre7.orig/mount/nfsmount.c
+++ util-linux-ng-2.12r+2.13pre7/mount/nfsmount.c
@@ -317,7 +317,7 @@ int nfsmount(const char *spec, const cha
 	noacl = 0;
 	noac = 0;
 	retry = 10000;		/* 10000 minutes ~ 1 week */
-	tcp = 0;
+	tcp = 2;
 
 	mountprog = MOUNTPROG;
 	mountvers = 0;
@@ -437,6 +437,8 @@ int nfsmount(const char *spec, const cha
 			}
 		}
 	}
+
+retry_udp:
 	proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;
 
 	data.flags = (soft ? NFS_MOUNT_SOFT : 0)
@@ -740,7 +742,13 @@ int nfsmount(const char *spec, const cha
 		 * '0' for port (service unavailable), we then exit,
 		 * notifying the user, rather than hanging up mount.
 		 */
-		if (port == 0 && tcp == 1) {
+		if (port == 0 && tcp) {
+			if (tcp == 2) {
+				fprintf(stderr, "nfs server reported tcp not available, falling back to udp\n");
+				close(fsock);
+				tcp = 0;
+				goto retry_udp;
+			}
 			perror(_("nfs server reported service unavailable"));
 			goto fail;
 		}