NFSv4.2: Added NFS v4.2 support to the NFS client

This enable NFSv4.2 support. To enable this code the
CONFIG_NFS_V4_2 Kconfig define needs to be set and
the -o v4.2 mount option need to be used.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 59461c9..e7ee629 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -166,9 +166,9 @@
 	if (unlikely(p == NULL))
 		return htonl(NFS4ERR_RESOURCE);
 	hdr->minorversion = ntohl(*p++);
-	/* Check minor version is zero or one. */
-	if (hdr->minorversion <= 1) {
-		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 */
+	/* Check minor version is zero or one or two. */
+	if (hdr->minorversion <= 2) {
+		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 and v4.2 */
 	} else {
 		pr_warn_ratelimited("NFS: %s: NFSv4 server callback with "
 			"illegal minor version %u!\n",