NFS: Extend the -overs= mount option to allow 4.x minorversions

Allow the user to mount an NFSv4.0 or NFSv4.1 partition using a
standard syntax of '-overs=4.0', or '-overs=4.1' rather than the
more cumbersome '-overs=4,minorversion=1'.

See also the earlier patch by Dros Adamson, which added the
Linux-specific syntax '-ov4.0', '-ov4.1'.

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

1 files changed, 62 insertions, 22 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 8154accd1168..ab58bb9b6115 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -98,10 +98,10 @@ enum {
         Opt_namelen,
         Opt_mountport,
         Opt_mountvers,
-        Opt_nfsvers,
         Opt_minorversion,
 
         /* Mount options that take string arguments */
+        Opt_nfsvers,
         Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
         Opt_addr, Opt_mountaddr, Opt_clientaddr,
         Opt_lookupcache,
@@ -166,9 +166,10 @@ static const match_table_t nfs_mount_option_tokens = {
         { Opt_namelen, "namlen=%s" },
         { Opt_mountport, "mountport=%s" },
         { Opt_mountvers, "mountvers=%s" },
+        { Opt_minorversion, "minorversion=%s" },
+
         { Opt_nfsvers, "nfsvers=%s" },
         { Opt_nfsvers, "vers=%s" },
-        { Opt_minorversion, "minorversion=%s" },
 
         { Opt_sec, "sec=%s" },
         { Opt_proto, "proto=%s" },
@@ -262,6 +263,22 @@ static match_table_t nfs_local_lock_tokens = {
         { Opt_local_lock_err, NULL }
 };
 
+enum {
+        Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
+        Opt_vers_4_1,
+
+        Opt_vers_err
+};
+
+static match_table_t nfs_vers_tokens = {
+        { Opt_vers_2, "2" },
+        { Opt_vers_3, "3" },
+        { Opt_vers_4, "4" },
+        { Opt_vers_4_0, "4.0" },
+        { Opt_vers_4_1, "4.1" },
+
+        { Opt_vers_err, NULL }
+};
 
 static void nfs_umount_begin(struct super_block *);
 static int  nfs_statfs(struct dentry *, struct kstatfs *);
@@ -1064,6 +1081,40 @@ static int nfs_parse_security_flavors(char *value,
         return 1;
 }
 
+static int nfs_parse_version_string(char *string,
+                struct nfs_parsed_mount_data *mnt,
+                substring_t *args)
+{
+        mnt->flags &= ~NFS_MOUNT_VER3;
+        switch (match_token(string, nfs_vers_tokens, args)) {
+        case Opt_vers_2:
+                mnt->version = 2;
+                break;
+        case Opt_vers_3:
+                mnt->flags |= NFS_MOUNT_VER3;
+                mnt->version = 3;
+                break;
+        case Opt_vers_4:
+                /* Backward compatibility option. In future,
+                 * the mount program should always supply
+                 * a NFSv4 minor version number.
+                 */
+                mnt->version = 4;
+                break;
+        case Opt_vers_4_0:
+                mnt->version = 4;
+                mnt->minorversion = 0;
+                break;
+        case Opt_vers_4_1:
+                mnt->version = 4;
+                mnt->minorversion = 1;
+                break;
+        default:
+                return 0;
+        }
+        return 1;
+}
+
 static int nfs_get_option_str(substring_t args[], char **option)
 {
         kfree(*option);
@@ -1317,26 +1368,6 @@ static int nfs_parse_mount_options(char *raw,
                                 goto out_invalid_value;
                         mnt->mount_server.version = option;
                         break;
-                case Opt_nfsvers:
-                        if (nfs_get_option_ul(args, &option))
-                                goto out_invalid_value;
-                        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;
-                        case NFS4_VERSION:
-                                mnt->flags &= ~NFS_MOUNT_VER3;
-                                mnt->version = 4;
-                                break;
-                        default:
-                                goto out_invalid_value;
-                        }
-                        break;
                 case Opt_minorversion:
                         if (nfs_get_option_ul(args, &option))
                                 goto out_invalid_value;
@@ -1348,6 +1379,15 @@ static int nfs_parse_mount_options(char *raw,
                 /*
                  * options that take text values
                  */
+                case Opt_nfsvers:
+                        string = match_strdup(args);
+                        if (string == NULL)
+                                goto out_nomem;
+                        rc = nfs_parse_version_string(string, mnt, args);
+                        kfree(string);
+                        if (!rc)
+                                goto out_invalid_value;
+                        break;
                 case Opt_sec:
                         string = match_strdup(args);
                         if (string == NULL)