NFS: Make v2 configurable

With this patch NFS v2 can be disabled during Kconfig.  I default the
option to "y" to match the current behavior.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 27 insertions, 4 deletions

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 2a0e6c599147..66b0f4cb520f 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -29,6 +29,16 @@ config NFS_FS
 
           If unsure, say N.
 
+config NFS_V2
+        bool "NFS client support for NFS version 2"
+        depends on NFS_FS
+        default y
+        help
+          This option enables support for version 2 of the NFS protocol
+          (RFC 1094) in the kernel's NFS client.
+
+          If unsure, say Y.
+
 config NFS_V3
         bool "NFS client support for NFS version 3"
         depends on NFS_FS
diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index b58613d0abb3..7ddd45d9f170 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -4,11 +4,12 @@
 
 obj-$(CONFIG_NFS_FS) += nfs.o
 
-nfs-y                   := client.o dir.o file.o getroot.o inode.o super.o nfs2xdr.o \
-                           direct.o pagelist.o proc.o read.o symlink.o unlink.o \
+nfs-y                   := client.o dir.o file.o getroot.o inode.o super.o \
+                           direct.o pagelist.o read.o symlink.o unlink.o \
                            write.o namespace.o mount_clnt.o \
                            dns_resolve.o cache_lib.o
 nfs-$(CONFIG_ROOT_NFS)  += nfsroot.o
+nfs-$(CONFIG_NFS_V2)    += proc.o nfs2xdr.o
 nfs-$(CONFIG_NFS_V3)    += nfs3proc.o nfs3xdr.o
 nfs-$(CONFIG_NFS_V3_ACL)        += nfs3acl.o
 nfs-$(CONFIG_NFS_V4)    += nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index a8f8de618d73..8f1c65210afb 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -90,7 +90,9 @@ static bool nfs4_disable_idmapping = true;
  * RPC cruft for NFS
  */
 static const struct rpc_version *nfs_version[5] = {
+#ifdef CONFIG_NFS_V2
         [2]                     = &nfs_version2,
+#endif
 #ifdef CONFIG_NFS_V3
         [3]                     = &nfs_version3,
 #endif
@@ -847,7 +849,7 @@ static int nfs_init_server(struct nfs_server *server,
                 .hostname = data->nfs_server.hostname,
                 .addr = (const struct sockaddr *)&data->nfs_server.address,
                 .addrlen = data->nfs_server.addrlen,
-                .rpc_ops = &nfs_v2_clientops,
+                .rpc_ops = NULL,
                 .proto = data->nfs_server.protocol,
                 .net = data->net,
         };
@@ -857,10 +859,20 @@ static int nfs_init_server(struct nfs_server *server,
 
         dprintk("--> nfs_init_server()\n");
 
+        switch (data->version) {
+#ifdef CONFIG_NFS_V2
+        case 2:
+                cl_init.rpc_ops = &nfs_v2_clientops;
+                break;
+#endif
 #ifdef CONFIG_NFS_V3
-        if (data->version == 3)
+        case 3:
                 cl_init.rpc_ops = &nfs_v3_clientops;
+                break;
 #endif
+        default:
+                return -EPROTONOSUPPORT;
+        }
 
         nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
                         data->timeo, data->retrans);