NFS: Allow the "nfs" file system type to support NFSv4

When mounting an "nfs" type file system, recognize "v4," "vers=4," or
"nfsvers=4" mount options, and convert the file system to "nfs4" under
the covers.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[trondmy: fixed up binary mount code so it sets the 'version' field too]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 47 insertions, 2 deletions

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 5e686a4d744..e21b1bb9972 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -68,6 +68,7 @@ struct nfs_parsed_mount_data {
         unsigned int            auth_flavor_len;
         rpc_authflavor_t        auth_flavors[1];
         char                    *client_address;
+        unsigned int            version;
         unsigned int            minorversion;
         char                    *fscache_uniq;
 
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index c105e12197c..34b1ccf51ad 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -73,7 +73,7 @@ enum {
         Opt_cto, Opt_nocto,
         Opt_ac, Opt_noac,
         Opt_lock, Opt_nolock,
-        Opt_v2, Opt_v3,
+        Opt_v2, Opt_v3, Opt_v4,
         Opt_udp, Opt_tcp, Opt_rdma,
         Opt_acl, Opt_noacl,
         Opt_rdirplus, Opt_nordirplus,
@@ -127,6 +127,7 @@ static const match_table_t nfs_mount_option_tokens = {
         { Opt_nolock, "nolock" },
         { Opt_v2, "v2" },
         { Opt_v3, "v3" },
+        { Opt_v4, "v4" },
         { Opt_udp, "udp" },
         { Opt_tcp, "tcp" },
         { Opt_rdma, "rdma" },
@@ -934,10 +935,18 @@ static int nfs_parse_mount_options(char *raw,
                         break;
                 case Opt_v2:
                         mnt->flags &= ~NFS_MOUNT_VER3;
+                        mnt->version = 2;
                         break;
                 case Opt_v3:
                         mnt->flags |= NFS_MOUNT_VER3;
+                        mnt->version = 3;
                         break;
+#ifdef CONFIG_NFS_V4
+                case Opt_v4:
+                        mnt->flags &= ~NFS_MOUNT_VER3;
+                        mnt->version = 4;
+                        break;
+#endif
                 case Opt_udp:
                         mnt->flags &= ~NFS_MOUNT_TCP;
                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
@@ -1151,10 +1160,18 @@ static int nfs_parse_mount_options(char *raw,
                         switch (option) {
                         case NFS2_VERSION:
                                 mnt->flags &= ~NFS_MOUNT_VER3;
+                                mnt->version = 2;
                                 break;
                         case NFS3_VERSION:
                                 mnt->flags |= NFS_MOUNT_VER3;
+                                mnt->version = 3;
+                                break;
+#ifdef CONFIG_NFS_V4
+                        case NFS4_VERSION:
+                                mnt->flags &= ~NFS_MOUNT_VER3;
+                                mnt->version = 4;
                                 break;
+#endif
                         default:
                                 goto out_invalid_value;
                         }
@@ -1629,6 +1646,7 @@ static int nfs_validate_mount_data(void *options,
         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
         args->auth_flavors[0]   = RPC_AUTH_UNIX;
         args->auth_flavor_len   = 1;
+        args->minorversion      = 0;
 
         switch (data->version) {
         case 1:
@@ -1650,8 +1668,11 @@ static int nfs_validate_mount_data(void *options,
                         if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
                                 goto out_invalid_fh;
                         mntfh->size = data->root.size;
-                } else
+                        args->version = 3;
+                } else {
                         mntfh->size = NFS2_FHSIZE;
+                        args->version = 2;
+                }
 
 
                 memcpy(mntfh->data, data->root.data, mntfh->size);
@@ -1726,6 +1747,14 @@ static int nfs_validate_mount_data(void *options,
                 if (!nfs_verify_server_address(sap))
                         goto out_no_address;
 
+                if (args->version == 4)
+#ifdef CONFIG_NFS_V4
+                        return nfs4_validate_text_mount_data(options,
+                                                             args, dev_name);
+#else
+                        goto out_v4_not_compiled;
+#endif
+
                 nfs_set_default_port(sap, args->nfs_server.port, 0);
 
                 nfs_set_mount_transport_protocol(args);
@@ -1774,6 +1803,12 @@ out_v3_not_compiled:
         return -EPROTONOSUPPORT;
 #endif /* !CONFIG_NFS_V3 */
 
+#ifndef CONFIG_NFS_V4
+out_v4_not_compiled:
+        dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
+        return -EPROTONOSUPPORT;
+#endif /* !CONFIG_NFS_V4 */
+
 out_nomem:
         dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
         return -ENOMEM;
@@ -2069,6 +2104,14 @@ static int nfs_get_sb(struct file_system_type *fs_type,
         if (error < 0)
                 goto out;
 
+#ifdef CONFIG_NFS_V4
+        if (data->version == 4) {
+                error = nfs4_try_mount(flags, dev_name, data, mnt);
+                kfree(data->client_address);
+                goto out;
+        }
+#endif  /* CONFIG_NFS_V4 */
+
         /* Get a volume representation */
         server = nfs_create_server(data, mntfh);
         if (IS_ERR(server)) {
@@ -2320,6 +2363,7 @@ static int nfs4_validate_mount_data(void *options,
         args->nfs_server.port   = NFS_UNSPEC_PORT;
         args->auth_flavors[0]   = RPC_AUTH_UNIX;
         args->auth_flavor_len   = 1;
+        args->version           = 4;
         args->minorversion      = 0;
 
         switch (data->version) {