NFS: Allow the "nfs" file system type to support NFSv4
[pandora-kernel.git] / fs / nfs / super.c
index 26127b6..34b1ccf 100644 (file)
@@ -42,6 +42,8 @@
 #include <linux/smp_lock.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
+#include <linux/mnt_namespace.h>
+#include <linux/namei.h>
 #include <linux/nfs_idmap.h>
 #include <linux/vfs.h>
 #include <linux/inet.h>
@@ -71,7 +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,
@@ -90,6 +92,7 @@ enum {
        Opt_mountport,
        Opt_mountvers,
        Opt_nfsvers,
+       Opt_minorversion,
 
        /* Mount options that take string arguments */
        Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
@@ -124,6 +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" },
@@ -139,22 +143,23 @@ static const match_table_t nfs_mount_option_tokens = {
        { Opt_fscache_uniq, "fsc=%s" },
        { Opt_nofscache, "nofsc" },
 
-       { Opt_port, "port=%u" },
-       { Opt_rsize, "rsize=%u" },
-       { Opt_wsize, "wsize=%u" },
-       { Opt_bsize, "bsize=%u" },
-       { Opt_timeo, "timeo=%u" },
-       { Opt_retrans, "retrans=%u" },
-       { Opt_acregmin, "acregmin=%u" },
-       { Opt_acregmax, "acregmax=%u" },
-       { Opt_acdirmin, "acdirmin=%u" },
-       { Opt_acdirmax, "acdirmax=%u" },
-       { Opt_actimeo, "actimeo=%u" },
-       { Opt_namelen, "namlen=%u" },
-       { Opt_mountport, "mountport=%u" },
-       { Opt_mountvers, "mountvers=%u" },
-       { Opt_nfsvers, "nfsvers=%u" },
-       { Opt_nfsvers, "vers=%u" },
+       { Opt_port, "port=%s" },
+       { Opt_rsize, "rsize=%s" },
+       { Opt_wsize, "wsize=%s" },
+       { Opt_bsize, "bsize=%s" },
+       { Opt_timeo, "timeo=%s" },
+       { Opt_retrans, "retrans=%s" },
+       { Opt_acregmin, "acregmin=%s" },
+       { Opt_acregmax, "acregmax=%s" },
+       { Opt_acdirmin, "acdirmin=%s" },
+       { Opt_acdirmax, "acdirmax=%s" },
+       { Opt_actimeo, "actimeo=%s" },
+       { Opt_namelen, "namlen=%s" },
+       { Opt_mountport, "mountport=%s" },
+       { Opt_mountvers, "mountvers=%s" },
+       { Opt_nfsvers, "nfsvers=%s" },
+       { Opt_nfsvers, "vers=%s" },
+       { Opt_minorversion, "minorversion=%s" },
 
        { Opt_sec, "sec=%s" },
        { Opt_proto, "proto=%s" },
@@ -268,12 +273,20 @@ static const struct super_operations nfs_sops = {
 };
 
 #ifdef CONFIG_NFS_V4
+static int nfs4_validate_text_mount_data(void *options,
+       struct nfs_parsed_mount_data *args, const char *dev_name);
+static int nfs4_try_mount(int flags, const char *dev_name,
+       struct nfs_parsed_mount_data *data, struct vfsmount *mnt);
 static int nfs4_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+static int nfs4_remote_get_sb(struct file_system_type *fs_type,
+       int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
+static int nfs4_remote_referral_get_sb(struct file_system_type *fs_type,
+       int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 static void nfs4_kill_super(struct super_block *sb);
 
 static struct file_system_type nfs4_fs_type = {
@@ -284,6 +297,14 @@ static struct file_system_type nfs4_fs_type = {
        .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
+static struct file_system_type nfs4_remote_fs_type = {
+       .owner          = THIS_MODULE,
+       .name           = "nfs4",
+       .get_sb         = nfs4_remote_get_sb,
+       .kill_sb        = nfs4_kill_super,
+       .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
 struct file_system_type nfs4_xdev_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "nfs4",
@@ -292,6 +313,14 @@ struct file_system_type nfs4_xdev_fs_type = {
        .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
+static struct file_system_type nfs4_remote_referral_fs_type = {
+       .owner          = THIS_MODULE,
+       .name           = "nfs4",
+       .get_sb         = nfs4_remote_referral_get_sb,
+       .kill_sb        = nfs4_kill_super,
+       .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
 struct file_system_type nfs4_referral_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "nfs4",
@@ -514,7 +543,6 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
                const char *nostr;
        } nfs_info[] = {
                { NFS_MOUNT_SOFT, ",soft", ",hard" },
-               { NFS_MOUNT_INTR, ",intr", ",nointr" },
                { NFS_MOUNT_POSIX, ",posix", "" },
                { NFS_MOUNT_NOCTO, ",nocto", "" },
                { NFS_MOUNT_NOAC, ",noac", "" },
@@ -719,127 +747,23 @@ static int nfs_verify_server_address(struct sockaddr *addr)
        }
        }
 
+       dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
        return 0;
 }
 
-static void nfs_parse_ipv4_address(char *string, size_t str_len,
-                                  struct sockaddr *sap, size_t *addr_len)
-{
-       struct sockaddr_in *sin = (struct sockaddr_in *)sap;
-       u8 *addr = (u8 *)&sin->sin_addr.s_addr;
-
-       if (str_len <= INET_ADDRSTRLEN) {
-               dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
-                               (int)str_len, string);
-
-               sin->sin_family = AF_INET;
-               *addr_len = sizeof(*sin);
-               if (in4_pton(string, str_len, addr, '\0', NULL))
-                       return;
-       }
-
-       sap->sa_family = AF_UNSPEC;
-       *addr_len = 0;
-}
-
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
-static int nfs_parse_ipv6_scope_id(const char *string, const size_t str_len,
-                                  const char *delim,
-                                  struct sockaddr_in6 *sin6)
-{
-       char *p;
-       size_t len;
-
-       if ((string + str_len) == delim)
-               return 1;
-
-       if (*delim != IPV6_SCOPE_DELIMITER)
-               return 0;
-
-       if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
-               return 0;
-
-       len = (string + str_len) - delim - 1;
-       p = kstrndup(delim + 1, len, GFP_KERNEL);
-       if (p) {
-               unsigned long scope_id = 0;
-               struct net_device *dev;
-
-               dev = dev_get_by_name(&init_net, p);
-               if (dev != NULL) {
-                       scope_id = dev->ifindex;
-                       dev_put(dev);
-               } else {
-                       if (strict_strtoul(p, 10, &scope_id) == 0) {
-                               kfree(p);
-                               return 0;
-                       }
-               }
-
-               kfree(p);
-
-               sin6->sin6_scope_id = scope_id;
-               dfprintk(MOUNT, "NFS: IPv6 scope ID = %lu\n", scope_id);
-               return 1;
-       }
-
-       return 0;
-}
-
-static void nfs_parse_ipv6_address(char *string, size_t str_len,
-                                  struct sockaddr *sap, size_t *addr_len)
-{
-       struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
-       u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
-       const char *delim;
-
-       if (str_len <= INET6_ADDRSTRLEN) {
-               dfprintk(MOUNT, "NFS: parsing IPv6 address %*s\n",
-                               (int)str_len, string);
-
-               sin6->sin6_family = AF_INET6;
-               *addr_len = sizeof(*sin6);
-               if (in6_pton(string, str_len, addr,
-                                       IPV6_SCOPE_DELIMITER, &delim) != 0) {
-                       if (nfs_parse_ipv6_scope_id(string, str_len,
-                                                       delim, sin6) != 0)
-                               return;
-               }
-       }
-
-       sap->sa_family = AF_UNSPEC;
-       *addr_len = 0;
-}
-#else
-static void nfs_parse_ipv6_address(char *string, size_t str_len,
-                                  struct sockaddr *sap, size_t *addr_len)
-{
-       sap->sa_family = AF_UNSPEC;
-       *addr_len = 0;
-}
-#endif
-
 /*
- * Construct a sockaddr based on the contents of a string that contains
- * an IP address in presentation format.
- *
- * If there is a problem constructing the new sockaddr, set the address
- * family to AF_UNSPEC.
+ * Select between a default port value and a user-specified port value.
+ * If a zero value is set, then autobind will be used.
  */
-void nfs_parse_ip_address(char *string, size_t str_len,
-                                struct sockaddr *sap, size_t *addr_len)
+static void nfs_set_default_port(struct sockaddr *sap, const int parsed_port,
+                                const unsigned short default_port)
 {
-       unsigned int i, colons;
+       unsigned short port = default_port;
 
-       colons = 0;
-       for (i = 0; i < str_len; i++)
-               if (string[i] == ':')
-                       colons++;
+       if (parsed_port != NFS_UNSPEC_PORT)
+               port = parsed_port;
 
-       if (colons >= 2)
-               nfs_parse_ipv6_address(string, str_len, sap, addr_len);
-       else
-               nfs_parse_ipv4_address(string, str_len, sap, addr_len);
+       rpc_set_port(sap, port);
 }
 
 /*
@@ -881,8 +805,6 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
 
 /*
  * Parse the value of the 'sec=' option.
- *
- * The flavor_len setting is for v4 mounts.
  */
 static int nfs_parse_security_flavors(char *value,
                                      struct nfs_parsed_mount_data *mnt)
@@ -893,61 +815,46 @@ static int nfs_parse_security_flavors(char *value,
 
        switch (match_token(value, nfs_secflavor_tokens, args)) {
        case Opt_sec_none:
-               mnt->auth_flavor_len = 0;
                mnt->auth_flavors[0] = RPC_AUTH_NULL;
                break;
        case Opt_sec_sys:
-               mnt->auth_flavor_len = 0;
                mnt->auth_flavors[0] = RPC_AUTH_UNIX;
                break;
        case Opt_sec_krb5:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
                break;
        case Opt_sec_krb5i:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
                break;
        case Opt_sec_krb5p:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
                break;
        case Opt_sec_lkey:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
                break;
        case Opt_sec_lkeyi:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
                break;
        case Opt_sec_lkeyp:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
                break;
        case Opt_sec_spkm:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
                break;
        case Opt_sec_spkmi:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
                break;
        case Opt_sec_spkmp:
-               mnt->auth_flavor_len = 1;
                mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
                break;
        default:
                return 0;
        }
 
+       mnt->auth_flavor_len = 1;
        return 1;
 }
 
-static void nfs_parse_invalid_value(const char *option)
-{
-       dfprintk(MOUNT, "NFS:   bad value specified for %s option\n", option);
-}
-
 /*
  * Error-check and convert a string of mount options from user space into
  * a data structure.  The whole mount string is processed; bad options are
@@ -958,7 +865,7 @@ static int nfs_parse_mount_options(char *raw,
                                   struct nfs_parsed_mount_data *mnt)
 {
        char *p, *string, *secdata;
-       int rc, sloppy = 0, errors = 0;
+       int rc, sloppy = 0, invalid_option = 0;
 
        if (!raw) {
                dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
@@ -982,7 +889,8 @@ static int nfs_parse_mount_options(char *raw,
 
        while ((p = strsep(&raw, ",")) != NULL) {
                substring_t args[MAX_OPT_ARGS];
-               int option, token;
+               unsigned long option;
+               int token;
 
                if (!*p)
                        continue;
@@ -1027,10 +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;
@@ -1091,126 +1007,187 @@ static int nfs_parse_mount_options(char *raw,
                 * options that take numeric values
                 */
                case Opt_port:
-                       if (match_int(args, &option) ||
-                           option < 0 || option > USHORT_MAX) {
-                               errors++;
-                               nfs_parse_invalid_value("port");
-                       } else
-                               mnt->nfs_server.port = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0 || option > USHORT_MAX)
+                               goto out_invalid_value;
+                       mnt->nfs_server.port = option;
                        break;
                case Opt_rsize:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("rsize");
-                       } else
-                               mnt->rsize = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->rsize = option;
                        break;
                case Opt_wsize:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("wsize");
-                       } else
-                               mnt->wsize = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->wsize = option;
                        break;
                case Opt_bsize:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("bsize");
-                       } else
-                               mnt->bsize = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->bsize = option;
                        break;
                case Opt_timeo:
-                       if (match_int(args, &option) || option <= 0) {
-                               errors++;
-                               nfs_parse_invalid_value("timeo");
-                       } else
-                               mnt->timeo = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0 || option == 0)
+                               goto out_invalid_value;
+                       mnt->timeo = option;
                        break;
                case Opt_retrans:
-                       if (match_int(args, &option) || option <= 0) {
-                               errors++;
-                               nfs_parse_invalid_value("retrans");
-                       } else
-                               mnt->retrans = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0 || option == 0)
+                               goto out_invalid_value;
+                       mnt->retrans = option;
                        break;
                case Opt_acregmin:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("acregmin");
-                       } else
-                               mnt->acregmin = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->acregmin = option;
                        break;
                case Opt_acregmax:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("acregmax");
-                       } else
-                               mnt->acregmax = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->acregmax = option;
                        break;
                case Opt_acdirmin:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("acdirmin");
-                       } else
-                               mnt->acdirmin = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->acdirmin = option;
                        break;
                case Opt_acdirmax:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("acdirmax");
-                       } else
-                               mnt->acdirmax = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->acdirmax = option;
                        break;
                case Opt_actimeo:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("actimeo");
-                       } else
-                               mnt->acregmin = mnt->acregmax =
-                               mnt->acdirmin = mnt->acdirmax = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->acregmin = mnt->acregmax =
+                       mnt->acdirmin = mnt->acdirmax = option;
                        break;
                case Opt_namelen:
-                       if (match_int(args, &option) || option < 0) {
-                               errors++;
-                               nfs_parse_invalid_value("namlen");
-                       } else
-                               mnt->namlen = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       mnt->namlen = option;
                        break;
                case Opt_mountport:
-                       if (match_int(args, &option) ||
-                           option < 0 || option > USHORT_MAX) {
-                               errors++;
-                               nfs_parse_invalid_value("mountport");
-                       } else
-                               mnt->mount_server.port = option;
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0 || option > USHORT_MAX)
+                               goto out_invalid_value;
+                       mnt->mount_server.port = option;
                        break;
                case Opt_mountvers:
-                       if (match_int(args, &option) ||
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0 ||
                            option < NFS_MNT_VERSION ||
-                           option > NFS_MNT3_VERSION) {
-                               errors++;
-                               nfs_parse_invalid_value("mountvers");
-                       } else
-                               mnt->mount_server.version = option;
+                           option > NFS_MNT3_VERSION)
+                               goto out_invalid_value;
+                       mnt->mount_server.version = option;
                        break;
                case Opt_nfsvers:
-                       if (match_int(args, &option)) {
-                               errors++;
-                               nfs_parse_invalid_value("nfsvers");
-                               break;
-                       }
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               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;
+#ifdef CONFIG_NFS_V4
+                       case NFS4_VERSION:
+                               mnt->flags &= ~NFS_MOUNT_VER3;
+                               mnt->version = 4;
                                break;
+#endif
                        default:
-                               errors++;
-                               nfs_parse_invalid_value("nfsvers");
+                               goto out_invalid_value;
                        }
                        break;
+               case Opt_minorversion:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       rc = strict_strtoul(string, 10, &option);
+                       kfree(string);
+                       if (rc != 0)
+                               goto out_invalid_value;
+                       if (option > NFS4_MAX_MINOR_VERSION)
+                               goto out_invalid_value;
+                       mnt->minorversion = option;
+                       break;
 
                /*
                 * options that take text values
@@ -1222,9 +1199,9 @@ static int nfs_parse_mount_options(char *raw,
                        rc = nfs_parse_security_flavors(string, mnt);
                        kfree(string);
                        if (!rc) {
-                               errors++;
                                dfprintk(MOUNT, "NFS:   unrecognized "
                                                "security flavor\n");
+                               return 0;
                        }
                        break;
                case Opt_proto:
@@ -1238,23 +1215,25 @@ static int nfs_parse_mount_options(char *raw,
                        case Opt_xprt_udp:
                                mnt->flags &= ~NFS_MOUNT_TCP;
                                mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+                               kfree(string);
                                break;
                        case Opt_xprt_tcp:
                                mnt->flags |= NFS_MOUNT_TCP;
                                mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+                               kfree(string);
                                break;
                        case Opt_xprt_rdma:
                                /* vector side protocols to TCP */
                                mnt->flags |= NFS_MOUNT_TCP;
                                mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
                                xprt_load_transport(string);
+                               kfree(string);
                                break;
                        default:
-                               errors++;
                                dfprintk(MOUNT, "NFS:   unrecognized "
                                                "transport protocol\n");
+                               return 0;
                        }
-                       kfree(string);
                        break;
                case Opt_mountproto:
                        string = match_strdup(args);
@@ -1273,20 +1252,23 @@ static int nfs_parse_mount_options(char *raw,
                                break;
                        case Opt_xprt_rdma: /* not used for side protocols */
                        default:
-                               errors++;
                                dfprintk(MOUNT, "NFS:   unrecognized "
                                                "transport protocol\n");
+                               return 0;
                        }
                        break;
                case Opt_addr:
                        string = match_strdup(args);
                        if (string == NULL)
                                goto out_nomem;
-                       nfs_parse_ip_address(string, strlen(string),
-                                            (struct sockaddr *)
-                                               &mnt->nfs_server.address,
-                                            &mnt->nfs_server.addrlen);
+                       mnt->nfs_server.addrlen =
+                               rpc_pton(string, strlen(string),
+                                       (struct sockaddr *)
+                                       &mnt->nfs_server.address,
+                                       sizeof(mnt->nfs_server.address));
                        kfree(string);
+                       if (mnt->nfs_server.addrlen == 0)
+                               goto out_invalid_address;
                        break;
                case Opt_clientaddr:
                        string = match_strdup(args);
@@ -1306,11 +1288,14 @@ static int nfs_parse_mount_options(char *raw,
                        string = match_strdup(args);
                        if (string == NULL)
                                goto out_nomem;
-                       nfs_parse_ip_address(string, strlen(string),
-                                            (struct sockaddr *)
-                                               &mnt->mount_server.address,
-                                            &mnt->mount_server.addrlen);
+                       mnt->mount_server.addrlen =
+                               rpc_pton(string, strlen(string),
+                                       (struct sockaddr *)
+                                       &mnt->mount_server.address,
+                                       sizeof(mnt->mount_server.address));
                        kfree(string);
+                       if (mnt->mount_server.addrlen == 0)
+                               goto out_invalid_address;
                        break;
                case Opt_lookupcache:
                        string = match_strdup(args);
@@ -1331,9 +1316,9 @@ static int nfs_parse_mount_options(char *raw,
                                        mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
                                        break;
                                default:
-                                       errors++;
                                        dfprintk(MOUNT, "NFS:   invalid "
                                                        "lookupcache argument\n");
+                                       return 0;
                        };
                        break;
 
@@ -1351,20 +1336,23 @@ static int nfs_parse_mount_options(char *raw,
                        break;
 
                default:
-                       errors++;
+                       invalid_option = 1;
                        dfprintk(MOUNT, "NFS:   unrecognized mount option "
                                        "'%s'\n", p);
                }
        }
 
-       if (errors > 0) {
-               dfprintk(MOUNT, "NFS: parsing encountered %d error%s\n",
-                               errors, (errors == 1 ? "" : "s"));
-               if (!sloppy)
-                       return 0;
-       }
+       if (!sloppy && invalid_option)
+               return 0;
+
        return 1;
 
+out_invalid_address:
+       printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
+       return 0;
+out_invalid_value:
+       printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
+       return 0;
 out_nomem:
        printk(KERN_INFO "NFS: not enough memory to parse option\n");
        return 0;
@@ -1374,6 +1362,52 @@ out_security_failure:
        return 0;
 }
 
+/*
+ * Match the requested auth flavors with the list returned by
+ * the server.  Returns zero and sets the mount's authentication
+ * flavor on success; returns -EACCES if server does not support
+ * the requested flavor.
+ */
+static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
+                            struct nfs_mount_request *request)
+{
+       unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
+
+       /*
+        * Certain releases of Linux's mountd return an empty
+        * flavor list.  To prevent behavioral regression with
+        * these servers (ie. rejecting mounts that used to
+        * succeed), revert to pre-2.6.32 behavior (no checking)
+        * if the returned flavor list is empty.
+        */
+       if (server_authlist_len == 0)
+               return 0;
+
+       /*
+        * We avoid sophisticated negotiating here, as there are
+        * plenty of cases where we can get it wrong, providing
+        * either too little or too much security.
+        *
+        * RFC 2623, section 2.7 suggests we SHOULD prefer the
+        * flavor listed first.  However, some servers list
+        * AUTH_NULL first.  Our caller plants AUTH_SYS, the
+        * preferred default, in args->auth_flavors[0] if user
+        * didn't specify sec= mount option.
+        */
+       for (i = 0; i < args->auth_flavor_len; i++)
+               for (j = 0; j < server_authlist_len; j++)
+                       if (args->auth_flavors[i] == request->auth_flavs[j]) {
+                               dfprintk(MOUNT, "NFS: using auth flavor %d\n",
+                                       request->auth_flavs[j]);
+                               args->auth_flavors[0] = request->auth_flavs[j];
+                               return 0;
+                       }
+
+       dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
+       nfs_umount(request);
+       return -EACCES;
+}
+
 /*
  * Use the remote server's MOUNT service to request the NFS file handle
  * corresponding to the provided path.
@@ -1381,6 +1415,8 @@ out_security_failure:
 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
                         struct nfs_fh *root_fh)
 {
+       rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
+       unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
        struct nfs_mount_request request = {
                .sap            = (struct sockaddr *)
                                                &args->mount_server.address,
@@ -1388,6 +1424,8 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args,
                .protocol       = args->mount_server.protocol,
                .fh             = root_fh,
                .noresvport     = args->flags & NFS_MOUNT_NORESVPORT,
+               .auth_flav_len  = &server_authlist_len,
+               .auth_flavs     = server_authlist,
        };
        int status;
 
@@ -1413,23 +1451,25 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args,
                args->mount_server.addrlen = args->nfs_server.addrlen;
        }
        request.salen = args->mount_server.addrlen;
-
-       /*
-        * autobind will be used if mount_server.port == 0
-        */
-       nfs_set_port(request.sap, args->mount_server.port);
+       nfs_set_default_port(request.sap, args->mount_server.port, 0);
 
        /*
         * Now ask the mount server to map our export path
         * to a file handle.
         */
        status = nfs_mount(&request);
-       if (status == 0)
-               return 0;
+       if (status != 0) {
+               dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
+                               request.hostname, status);
+               return status;
+       }
 
-       dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
-                       request.hostname, status);
-       return status;
+       /*
+        * MNTv1 (NFSv2) does not support auth flavor negotiation.
+        */
+       if (args->mount_server.version != NFS_MNT3_VERSION)
+               return 0;
+       return nfs_walk_authlist(args, &request);
 }
 
 static int nfs_parse_simple_hostname(const char *dev_name,
@@ -1589,6 +1629,7 @@ static int nfs_validate_mount_data(void *options,
                                   const char *dev_name)
 {
        struct nfs_mount_data *data = (struct nfs_mount_data *)options;
+       struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
 
        if (data == NULL)
                goto out_no_data;
@@ -1600,10 +1641,12 @@ static int nfs_validate_mount_data(void *options,
        args->acregmax          = NFS_DEF_ACREGMAX;
        args->acdirmin          = NFS_DEF_ACDIRMIN;
        args->acdirmax          = NFS_DEF_ACDIRMAX;
-       args->mount_server.port = 0;    /* autobind unless user sets port */
-       args->nfs_server.port   = 0;    /* autobind unless user sets port */
+       args->mount_server.port = NFS_UNSPEC_PORT;
+       args->nfs_server.port   = NFS_UNSPEC_PORT;
        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:
@@ -1625,8 +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);
@@ -1648,11 +1694,9 @@ static int nfs_validate_mount_data(void *options,
                args->acdirmin          = data->acdirmin;
                args->acdirmax          = data->acdirmax;
 
-               memcpy(&args->nfs_server.address, &data->addr,
-                      sizeof(data->addr));
+               memcpy(sap, &data->addr, sizeof(data->addr));
                args->nfs_server.addrlen = sizeof(data->addr);
-               if (!nfs_verify_server_address((struct sockaddr *)
-                                               &args->nfs_server.address))
+               if (!nfs_verify_server_address(sap))
                        goto out_no_address;
 
                if (!(data->flags & NFS_MOUNT_TCP))
@@ -1700,12 +1744,18 @@ static int nfs_validate_mount_data(void *options,
                if (nfs_parse_mount_options((char *)options, args) == 0)
                        return -EINVAL;
 
-               if (!nfs_verify_server_address((struct sockaddr *)
-                                               &args->nfs_server.address))
+               if (!nfs_verify_server_address(sap))
                        goto out_no_address;
 
-               nfs_set_port((struct sockaddr *)&args->nfs_server.address,
-                               args->nfs_server.port);
+               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);
 
@@ -1753,6 +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;
@@ -2048,6 +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)) {
@@ -2240,6 +2304,42 @@ static void nfs4_fill_super(struct super_block *sb)
        nfs_initialise_sb(sb);
 }
 
+static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
+{
+       args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3);
+}
+
+static int nfs4_validate_text_mount_data(void *options,
+                                        struct nfs_parsed_mount_data *args,
+                                        const char *dev_name)
+{
+       struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
+
+       nfs_set_default_port(sap, args->nfs_server.port, NFS_PORT);
+
+       nfs_validate_transport_protocol(args);
+
+       nfs4_validate_mount_flags(args);
+
+       if (args->auth_flavor_len > 1) {
+               dfprintk(MOUNT,
+                        "NFS4: Too many RPC auth flavours specified\n");
+               return -EINVAL;
+       }
+
+       if (args->client_address == NULL) {
+               dfprintk(MOUNT,
+                        "NFS4: mount program didn't pass callback address\n");
+               return -EINVAL;
+       }
+
+       return nfs_parse_devname(dev_name,
+                                  &args->nfs_server.hostname,
+                                  NFS4_MAXNAMLEN,
+                                  &args->nfs_server.export_path,
+                                  NFS4_MAXPATHLEN);
+}
+
 /*
  * Validate NFSv4 mount options
  */
@@ -2247,7 +2347,7 @@ static int nfs4_validate_mount_data(void *options,
                                    struct nfs_parsed_mount_data *args,
                                    const char *dev_name)
 {
-       struct sockaddr_in *ap;
+       struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
        struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
        char *c;
 
@@ -2260,22 +2360,22 @@ static int nfs4_validate_mount_data(void *options,
        args->acregmax          = NFS_DEF_ACREGMAX;
        args->acdirmin          = NFS_DEF_ACDIRMIN;
        args->acdirmax          = NFS_DEF_ACDIRMAX;
-       args->nfs_server.port   = NFS_PORT; /* 2049 unless user set port= */
+       args->nfs_server.port   = NFS_UNSPEC_PORT;
        args->auth_flavors[0]   = RPC_AUTH_UNIX;
-       args->auth_flavor_len   = 0;
+       args->auth_flavor_len   = 1;
+       args->version           = 4;
+       args->minorversion      = 0;
 
        switch (data->version) {
        case 1:
-               ap = (struct sockaddr_in *)&args->nfs_server.address;
                if (data->host_addrlen > sizeof(args->nfs_server.address))
                        goto out_no_address;
                if (data->host_addrlen == 0)
                        goto out_no_address;
                args->nfs_server.addrlen = data->host_addrlen;
-               if (copy_from_user(ap, data->host_addr, data->host_addrlen))
+               if (copy_from_user(sap, data->host_addr, data->host_addrlen))
                        return -EFAULT;
-               if (!nfs_verify_server_address((struct sockaddr *)
-                                               &args->nfs_server.address))
+               if (!nfs_verify_server_address(sap))
                        goto out_no_address;
 
                if (data->auth_flavourlen) {
@@ -2321,37 +2421,14 @@ static int nfs4_validate_mount_data(void *options,
                nfs_validate_transport_protocol(args);
 
                break;
-       default: {
-               int status;
-
+       default:
                if (nfs_parse_mount_options((char *)options, args) == 0)
                        return -EINVAL;
 
-               if (!nfs_verify_server_address((struct sockaddr *)
-                                               &args->nfs_server.address))
+               if (!nfs_verify_server_address(sap))
                        return -EINVAL;
 
-               nfs_set_port((struct sockaddr *)&args->nfs_server.address,
-                               args->nfs_server.port);
-
-               nfs_validate_transport_protocol(args);
-
-               if (args->auth_flavor_len > 1)
-                       goto out_inval_auth;
-
-               if (args->client_address == NULL)
-                       goto out_no_client_address;
-
-               status = nfs_parse_devname(dev_name,
-                                          &args->nfs_server.hostname,
-                                          NFS4_MAXNAMLEN,
-                                          &args->nfs_server.export_path,
-                                          NFS4_MAXPATHLEN);
-               if (status < 0)
-                       return status;
-
-               break;
-               }
+               return nfs4_validate_text_mount_data(options, args, dev_name);
        }
 
        return 0;
@@ -2368,19 +2445,15 @@ out_inval_auth:
 out_no_address:
        dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
        return -EINVAL;
-
-out_no_client_address:
-       dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
-       return -EINVAL;
 }
 
 /*
- * Get the superblock for an NFS4 mountpoint
+ * Get the superblock for the NFS4 root partition
  */
-static int nfs4_get_sb(struct file_system_type *fs_type,
+static int nfs4_remote_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
 {
-       struct nfs_parsed_mount_data *data;
+       struct nfs_parsed_mount_data *data = raw_data;
        struct super_block *s;
        struct nfs_server *server;
        struct nfs_fh *mntfh;
@@ -2391,18 +2464,12 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
        };
        int error = -ENOMEM;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
        mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
        if (data == NULL || mntfh == NULL)
                goto out_free_fh;
 
        security_init_mnt_opts(&data->lsm_opts);
 
-       /* Validate the mount data */
-       error = nfs4_validate_mount_data(raw_data, data, dev_name);
-       if (error < 0)
-               goto out;
-
        /* Get a volume representation */
        server = nfs4_create_server(data, mntfh);
        if (IS_ERR(server)) {
@@ -2415,7 +2482,7 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
                compare_super = NULL;
 
        /* Get a superblock - note that we may end up sharing one that already exists */
-       s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
+       s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto out_free;
@@ -2452,14 +2519,9 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
        error = 0;
 
 out:
-       kfree(data->client_address);
-       kfree(data->nfs_server.export_path);
-       kfree(data->nfs_server.hostname);
-       kfree(data->fscache_uniq);
        security_free_mnt_opts(&data->lsm_opts);
 out_free_fh:
        kfree(mntfh);
-       kfree(data);
        return error;
 
 out_free:
@@ -2473,16 +2535,153 @@ error_splat_super:
        goto out;
 }
 
+static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
+               int flags, void *data, const char *hostname)
+{
+       struct vfsmount *root_mnt;
+       char *root_devname;
+       size_t len;
+
+       len = strlen(hostname) + 3;
+       root_devname = kmalloc(len, GFP_KERNEL);
+       if (root_devname == NULL)
+               return ERR_PTR(-ENOMEM);
+       snprintf(root_devname, len, "%s:/", hostname);
+       root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
+       kfree(root_devname);
+       return root_mnt;
+}
+
+static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
+{
+       char *page = (char *) __get_free_page(GFP_KERNEL);
+       char *devname, *tmp;
+
+       if (page == NULL)
+               return;
+       devname = nfs_path(path->mnt->mnt_devname,
+                       path->mnt->mnt_root, path->dentry,
+                       page, PAGE_SIZE);
+       if (devname == NULL)
+               goto out_freepage;
+       tmp = kstrdup(devname, GFP_KERNEL);
+       if (tmp == NULL)
+               goto out_freepage;
+       kfree(mnt->mnt_devname);
+       mnt->mnt_devname = tmp;
+out_freepage:
+       free_page((unsigned long)page);
+}
+
+static int nfs_follow_remote_path(struct vfsmount *root_mnt,
+               const char *export_path, struct vfsmount *mnt_target)
+{
+       struct mnt_namespace *ns_private;
+       struct nameidata nd;
+       struct super_block *s;
+       int ret;
+
+       ns_private = create_mnt_ns(root_mnt);
+       ret = PTR_ERR(ns_private);
+       if (IS_ERR(ns_private))
+               goto out_mntput;
+
+       ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
+                       export_path, LOOKUP_FOLLOW, &nd);
+
+       put_mnt_ns(ns_private);
+
+       if (ret != 0)
+               goto out_err;
+
+       s = nd.path.mnt->mnt_sb;
+       atomic_inc(&s->s_active);
+       mnt_target->mnt_sb = s;
+       mnt_target->mnt_root = dget(nd.path.dentry);
+
+       /* Correct the device pathname */
+       nfs_fix_devname(&nd.path, mnt_target);
+
+       path_put(&nd.path);
+       down_write(&s->s_umount);
+       return 0;
+out_mntput:
+       mntput(root_mnt);
+out_err:
+       return ret;
+}
+
+static int nfs4_try_mount(int flags, const char *dev_name,
+                        struct nfs_parsed_mount_data *data,
+                        struct vfsmount *mnt)
+{
+       char *export_path;
+       struct vfsmount *root_mnt;
+       int error;
+
+       dfprintk(MOUNT, "--> nfs4_try_mount()\n");
+
+       export_path = data->nfs_server.export_path;
+       data->nfs_server.export_path = "/";
+       root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
+                       data->nfs_server.hostname);
+       data->nfs_server.export_path = export_path;
+
+       error = PTR_ERR(root_mnt);
+       if (IS_ERR(root_mnt))
+               goto out;
+
+       error = nfs_follow_remote_path(root_mnt, export_path, mnt);
+
+out:
+       dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
+                       error != 0 ? " [error]" : "");
+       return error;
+}
+
+/*
+ * Get the superblock for an NFS4 mountpoint
+ */
+static int nfs4_get_sb(struct file_system_type *fs_type,
+       int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
+{
+       struct nfs_parsed_mount_data *data;
+       int error = -ENOMEM;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (data == NULL)
+               goto out_free_data;
+
+       /* Validate the mount data */
+       error = nfs4_validate_mount_data(raw_data, data, dev_name);
+       if (error < 0)
+               goto out;
+
+       error = nfs4_try_mount(flags, dev_name, data, mnt);
+
+out:
+       kfree(data->client_address);
+       kfree(data->nfs_server.export_path);
+       kfree(data->nfs_server.hostname);
+       kfree(data->fscache_uniq);
+out_free_data:
+       kfree(data);
+       dprintk("<-- nfs4_get_sb() = %d%s\n", error,
+                       error != 0 ? " [error]" : "");
+       return error;
+}
+
 static void nfs4_kill_super(struct super_block *sb)
 {
        struct nfs_server *server = NFS_SB(sb);
 
+       dprintk("--> %s\n", __func__);
        nfs_super_return_all_delegations(sb);
        kill_anon_super(sb);
-
        nfs4_renewd_prepare_shutdown(server);
        nfs_fscache_release_super_cookie(sb);
        nfs_free_server(server);
+       dprintk("<-- %s\n", __func__);
 }
 
 /*
@@ -2568,12 +2767,9 @@ error_splat_super:
        return error;
 }
 
-/*
- * Create an NFS4 server record on referral traversal
- */
-static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
-                               const char *dev_name, void *raw_data,
-                               struct vfsmount *mnt)
+static int nfs4_remote_referral_get_sb(struct file_system_type *fs_type,
+               int flags, const char *dev_name, void *raw_data,
+               struct vfsmount *mnt)
 {
        struct nfs_clone_mount *data = raw_data;
        struct super_block *s;
@@ -2652,4 +2848,36 @@ error_splat_super:
        return error;
 }
 
+/*
+ * Create an NFS4 server record on referral traversal
+ */
+static int nfs4_referral_get_sb(struct file_system_type *fs_type,
+               int flags, const char *dev_name, void *raw_data,
+               struct vfsmount *mnt)
+{
+       struct nfs_clone_mount *data = raw_data;
+       char *export_path;
+       struct vfsmount *root_mnt;
+       int error;
+
+       dprintk("--> nfs4_referral_get_sb()\n");
+
+       export_path = data->mnt_path;
+       data->mnt_path = "/";
+
+       root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
+                       flags, data, data->hostname);
+       data->mnt_path = export_path;
+
+       error = PTR_ERR(root_mnt);
+       if (IS_ERR(root_mnt))
+               goto out;
+
+       error = nfs_follow_remote_path(root_mnt, export_path, mnt);
+out:
+       dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
+                       error != 0 ? " [error]" : "");
+       return error;
+}
+
 #endif /* CONFIG_NFS_V4 */