6 files changed, 39 insertions, 4 deletions
diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 13ca196385f5..a048928340a7 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -104,6 +104,15 @@ config NFS_V4_1
 
 	  If unsure, say N.
 
+config NFS_V4_2
+	bool "NFS client support for NFSv4.2"
+	depends on NFS_V4_1
+	help
+	  This option enables support for minor version 2 of the NFSv4 protocol
+	  in the kernel's NFS client.
+
+	  If unsure, say N.
+
 config PNFS_FILE_LAYOUT
 	tristate
 	depends on NFS_V4_1
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index cff089a412c7..78e368d8186d 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -282,6 +282,7 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct n
 			ret = nfs4_callback_up_net(serv, net);
 			break;
 		case 1:
+		case 2:
 			ret = nfs41_callback_up_net(serv, net);
 			break;
 		default:
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 59461c957d9d..e7ee62929811 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -166,9 +166,9 @@ static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound
 	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",
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 947b0c908aa9..2a297eeda474 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -66,6 +66,11 @@ struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
 	if (err)
 		goto error;
 
+	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
+		err = -EINVAL;
+		goto error;
+	}
+
 	spin_lock_init(&clp->cl_lock);
 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8fbc10054115..abf46f4b5d19 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7004,11 +7004,26 @@ static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
 };
 #endif
 
+#if defined(CONFIG_NFS_V4_2)
+static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
+	.minor_version = 2,
+	.call_sync = nfs4_call_sync_sequence,
+	.match_stateid = nfs41_match_stateid,
+	.find_root_sec = nfs41_find_root_sec,
+	.reboot_recovery_ops = &nfs41_reboot_recovery_ops,
+	.nograce_recovery_ops = &nfs41_nograce_recovery_ops,
+	.state_renewal_ops = &nfs41_state_renewal_ops,
+};
+#endif
+
 const struct nfs4_minor_version_ops *nfs_v4_minor_ops[] = {
 	[0] = &nfs_v4_0_minor_ops,
 #if defined(CONFIG_NFS_V4_1)
 	[1] = &nfs_v4_1_minor_ops,
 #endif
+#if defined(CONFIG_NFS_V4_2)
+	[2] = &nfs_v4_2_minor_ops,
+#endif
 };
 
 const struct inode_operations nfs4_dir_inode_operations = {
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index c1bbb53d444a..2e94f2168b03 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -269,7 +269,7 @@ static match_table_t nfs_local_lock_tokens = {
 
 enum {
 	Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
-	Opt_vers_4_1,
+	Opt_vers_4_1, Opt_vers_4_2,
 
 	Opt_vers_err
 };
@@ -280,6 +280,7 @@ static match_table_t nfs_vers_tokens = {
 	{ Opt_vers_4, "4" },
 	{ Opt_vers_4_0, "4.0" },
 	{ Opt_vers_4_1, "4.1" },
+	{ Opt_vers_4_2, "4.2" },
 
 	{ Opt_vers_err, NULL }
 };
@@ -1097,6 +1098,10 @@ static int nfs_parse_version_string(char *string,
 		mnt->version = 4;
 		mnt->minorversion = 1;
 		break;
+	case Opt_vers_4_2:
+		mnt->version = 4;
+		mnt->minorversion = 2;
+		break;
 	default:
 		return 0;
 	}