NFS: dont allow minorversion= opt when vers != 4

Don't allow invalid 'vers' and 'minorversion' combinations in mount options,
such as "vers=3,minorversion=1".
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/super.c

@@ -1531,6 +1531,9 @@ static int nfs_parse_mount_options(char *raw,
 	if (!sloppy && invalid_option)
 		return 0;
 
+	if (mnt->minorversion && mnt->version != 4)
+		goto out_minorversion_mismatch;
+
 	/*
 	 * verify that any proto=/mountproto= options match the address
 	 * familiies in the addr=/mountaddr= options.
@@ -1564,6 +1567,10 @@ static int nfs_parse_mount_options(char *raw,
 out_invalid_value:
 	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
 	return 0;
+out_minorversion_mismatch:
+	printk(KERN_INFO "NFS: mount option vers=%u does not support "
+			 "minorversion=%u\n", mnt->version, mnt->minorversion);
+	return 0;
 out_nomem:
 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
 	return 0;