2 files changed, 36 insertions, 2 deletions

diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index 41cf8934f4e7..84326e9fb47a 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -32,6 +32,8 @@ enum nfs4_callback_opnum {
         OP_CB_WANTS_CANCELLED = 12,
         OP_CB_NOTIFY_LOCK   = 13,
         OP_CB_NOTIFY_DEVICEID = 14,
+/* Callback operations new to NFSv4.2 */
+        OP_CB_OFFLOAD = 15,
         OP_CB_ILLEGAL = 10044,
 };
 
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 77c0b881520f..d450c21bc382 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -786,6 +786,26 @@ static void nfs4_cb_free_slot(struct cb_process_state *cps)
 }
 #endif /* CONFIG_NFS_V4_1 */
 
+#ifdef CONFIG_NFS_V4_2
+static __be32
+preprocess_nfs42_op(int nop, unsigned int op_nr, struct callback_op **op)
+{
+        __be32 status = preprocess_nfs41_op(nop, op_nr, op);
+        if (status != htonl(NFS4ERR_OP_ILLEGAL))
+                return status;
+
+        if (op_nr == OP_CB_OFFLOAD)
+                return htonl(NFS4ERR_NOTSUPP);
+        return htonl(NFS4ERR_OP_ILLEGAL);
+}
+#else /* CONFIG_NFS_V4_2 */
+static __be32
+preprocess_nfs42_op(int nop, unsigned int op_nr, struct callback_op **op)
+{
+        return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
+}
+#endif /* CONFIG_NFS_V4_2 */
+
 static __be32
 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
 {
@@ -820,8 +840,20 @@ static __be32 process_op(int nop, struct svc_rqst *rqstp,
         dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
                 __func__, cps->minorversion, nop, op_nr);
 
-        status = cps->minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
-                                preprocess_nfs4_op(op_nr, &op);
+        switch (cps->minorversion) {
+        case 0:
+                status = preprocess_nfs4_op(op_nr, &op);
+                break;
+        case 1:
+                status = preprocess_nfs41_op(nop, op_nr, &op);
+                break;
+        case 2:
+                status = preprocess_nfs42_op(nop, op_nr, &op);
+                break;
+        default:
+                status = htonl(NFS4ERR_MINOR_VERS_MISMATCH);
+        }
+
         if (status == htonl(NFS4ERR_OP_ILLEGAL))
                 op_nr = OP_CB_ILLEGAL;
         if (status)