NFS: Treat "intr" and "nointr" options as deprecated
[safe/jmp/linux-2.6] / fs / nfs / super.c
index baf75e9..f824c41 100644 (file)
@@ -33,6 +33,8 @@
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/stats.h>
 #include <linux/sunrpc/metrics.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/sunrpc/xprtrdma.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_mount.h>
 #include <linux/nfs4_mount.h>
 #include <linux/nfs_idmap.h>
 #include <linux/vfs.h>
 #include <linux/inet.h>
+#include <linux/in6.h>
+#include <net/ipv6.h>
 #include <linux/nfs_xdr.h>
 #include <linux/magic.h>
+#include <linux/parser.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
 
 #define NFSDBG_FACILITY                NFSDBG_VFS
 
-static void nfs_umount_begin(struct vfsmount *, int);
+enum {
+       /* Mount options that take no arguments */
+       Opt_soft, Opt_hard,
+       Opt_posix, Opt_noposix,
+       Opt_cto, Opt_nocto,
+       Opt_ac, Opt_noac,
+       Opt_lock, Opt_nolock,
+       Opt_v2, Opt_v3,
+       Opt_udp, Opt_tcp, Opt_rdma,
+       Opt_acl, Opt_noacl,
+       Opt_rdirplus, Opt_nordirplus,
+       Opt_sharecache, Opt_nosharecache,
+
+       /* Mount options that take integer arguments */
+       Opt_port,
+       Opt_rsize, Opt_wsize, Opt_bsize,
+       Opt_timeo, Opt_retrans,
+       Opt_acregmin, Opt_acregmax,
+       Opt_acdirmin, Opt_acdirmax,
+       Opt_actimeo,
+       Opt_namelen,
+       Opt_mountport,
+       Opt_mountvers,
+       Opt_nfsvers,
+
+       /* Mount options that take string arguments */
+       Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
+       Opt_addr, Opt_mountaddr, Opt_clientaddr,
+
+       /* Mount options that are ignored */
+       Opt_userspace, Opt_deprecated,
+
+       Opt_err
+};
+
+static match_table_t nfs_mount_option_tokens = {
+       { Opt_userspace, "bg" },
+       { Opt_userspace, "fg" },
+       { Opt_userspace, "retry=%s" },
+
+       { Opt_soft, "soft" },
+       { Opt_hard, "hard" },
+       { Opt_deprecated, "intr" },
+       { Opt_deprecated, "nointr" },
+       { Opt_posix, "posix" },
+       { Opt_noposix, "noposix" },
+       { Opt_cto, "cto" },
+       { Opt_nocto, "nocto" },
+       { Opt_ac, "ac" },
+       { Opt_noac, "noac" },
+       { Opt_lock, "lock" },
+       { Opt_nolock, "nolock" },
+       { Opt_v2, "v2" },
+       { Opt_v3, "v3" },
+       { Opt_udp, "udp" },
+       { Opt_tcp, "tcp" },
+       { Opt_rdma, "rdma" },
+       { Opt_acl, "acl" },
+       { Opt_noacl, "noacl" },
+       { Opt_rdirplus, "rdirplus" },
+       { Opt_nordirplus, "nordirplus" },
+       { Opt_sharecache, "sharecache" },
+       { Opt_nosharecache, "nosharecache" },
+
+       { 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_sec, "sec=%s" },
+       { Opt_proto, "proto=%s" },
+       { Opt_mountproto, "mountproto=%s" },
+       { Opt_addr, "addr=%s" },
+       { Opt_clientaddr, "clientaddr=%s" },
+       { Opt_mounthost, "mounthost=%s" },
+       { Opt_mountaddr, "mountaddr=%s" },
+
+       { Opt_err, NULL }
+};
+
+enum {
+       Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
+
+       Opt_xprt_err
+};
+
+static match_table_t nfs_xprt_protocol_tokens = {
+       { Opt_xprt_udp, "udp" },
+       { Opt_xprt_tcp, "tcp" },
+       { Opt_xprt_rdma, "rdma" },
+
+       { Opt_xprt_err, NULL }
+};
+
+enum {
+       Opt_sec_none, Opt_sec_sys,
+       Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
+       Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
+       Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
+
+       Opt_sec_err
+};
+
+static match_table_t nfs_secflavor_tokens = {
+       { Opt_sec_none, "none" },
+       { Opt_sec_none, "null" },
+       { Opt_sec_sys, "sys" },
+
+       { Opt_sec_krb5, "krb5" },
+       { Opt_sec_krb5i, "krb5i" },
+       { Opt_sec_krb5p, "krb5p" },
+
+       { Opt_sec_lkey, "lkey" },
+       { Opt_sec_lkeyi, "lkeyi" },
+       { Opt_sec_lkeyp, "lkeyp" },
+
+       { Opt_sec_spkm, "spkm3" },
+       { Opt_sec_spkmi, "spkm3i" },
+       { Opt_sec_spkmp, "spkm3p" },
+
+       { Opt_sec_err, NULL }
+};
+
+
+static void nfs_umount_begin(struct super_block *);
 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
@@ -65,6 +206,8 @@ static int nfs_get_sb(struct file_system_type *, int, const char *, void *, stru
 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
                int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 static void nfs_kill_super(struct super_block *);
+static void nfs_put_super(struct super_block *);
+static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 
 static struct file_system_type nfs_fs_type = {
        .owner          = THIS_MODULE,
@@ -86,11 +229,13 @@ static const struct super_operations nfs_sops = {
        .alloc_inode    = nfs_alloc_inode,
        .destroy_inode  = nfs_destroy_inode,
        .write_inode    = nfs_write_inode,
+       .put_super      = nfs_put_super,
        .statfs         = nfs_statfs,
        .clear_inode    = nfs_clear_inode,
        .umount_begin   = nfs_umount_begin,
        .show_options   = nfs_show_options,
        .show_stats     = nfs_show_stats,
+       .remount_fs     = nfs_remount,
 };
 
 #ifdef CONFIG_NFS_V4
@@ -135,10 +280,14 @@ static const struct super_operations nfs4_sops = {
        .umount_begin   = nfs_umount_begin,
        .show_options   = nfs_show_options,
        .show_stats     = nfs_show_stats,
+       .remount_fs     = nfs_remount,
 };
 #endif
 
-static struct shrinker *acl_shrinker;
+static struct shrinker acl_shrinker = {
+       .shrink         = nfs_access_cache_shrinker,
+       .seeks          = DEFAULT_SEEKS,
+};
 
 /*
  * Register the NFS filesystems
@@ -159,7 +308,7 @@ int __init register_nfs_fs(void)
        if (ret < 0)
                goto error_2;
 #endif
-       acl_shrinker = set_shrinker(DEFAULT_SEEKS, nfs_access_cache_shrinker);
+       register_shrinker(&acl_shrinker);
        return 0;
 
 #ifdef CONFIG_NFS_V4
@@ -177,15 +326,36 @@ error_0:
  */
 void __exit unregister_nfs_fs(void)
 {
-       if (acl_shrinker != NULL)
-               remove_shrinker(acl_shrinker);
+       unregister_shrinker(&acl_shrinker);
 #ifdef CONFIG_NFS_V4
        unregister_filesystem(&nfs4_fs_type);
-       nfs_unregister_sysctl();
 #endif
+       nfs_unregister_sysctl();
        unregister_filesystem(&nfs_fs_type);
 }
 
+void nfs_sb_active(struct nfs_server *server)
+{
+       atomic_inc(&server->active);
+}
+
+void nfs_sb_deactive(struct nfs_server *server)
+{
+       if (atomic_dec_and_test(&server->active))
+               wake_up(&server->active_wq);
+}
+
+static void nfs_put_super(struct super_block *sb)
+{
+       struct nfs_server *server = NFS_SB(sb);
+       /*
+        * Make sure there are no outstanding ops to this server.
+        * If so, wait for them to finish before allowing the
+        * unmount to continue.
+        */
+       wait_event(server->active_wq, atomic_read(&server->active) == 0);
+}
+
 /*
  * Deliver file system statistics to userspace
  */
@@ -238,7 +408,7 @@ static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
        return 0;
 
  out_err:
-       dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
+       dprintk("%s: statfs error = %d\n", __func__, -error);
        unlock_kernel();
        return error;
 }
@@ -274,10 +444,52 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
        return sec_flavours[i].str;
 }
 
+static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
+                                   int showdefaults)
+{
+       struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
+
+       switch (sap->sa_family) {
+       case AF_INET: {
+               struct sockaddr_in *sin = (struct sockaddr_in *)sap;
+               seq_printf(m, ",mountaddr=" NIPQUAD_FMT,
+                               NIPQUAD(sin->sin_addr.s_addr));
+               break;
+       }
+       case AF_INET6: {
+               struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
+               seq_printf(m, ",mountaddr=" NIP6_FMT,
+                               NIP6(sin6->sin6_addr));
+               break;
+       }
+       default:
+               if (showdefaults)
+                       seq_printf(m, ",mountaddr=unspecified");
+       }
+
+       if (nfss->mountd_version || showdefaults)
+               seq_printf(m, ",mountvers=%u", nfss->mountd_version);
+       if (nfss->mountd_port || showdefaults)
+               seq_printf(m, ",mountport=%u", nfss->mountd_port);
+
+       switch (nfss->mountd_protocol) {
+       case IPPROTO_UDP:
+               seq_printf(m, ",mountproto=udp");
+               break;
+       case IPPROTO_TCP:
+               seq_printf(m, ",mountproto=tcp");
+               break;
+       default:
+               if (showdefaults)
+                       seq_printf(m, ",mountproto=auto");
+       }
+}
+
 /*
  * Describe the mount options in force on this server representation
  */
-static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
+static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
+                                  int showdefaults)
 {
        static const struct proc_nfs_info {
                int flag;
@@ -285,51 +497,60 @@ 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", "" },
+               { NFS_MOUNT_INTR, ",intr", ",nointr" },
+               { NFS_MOUNT_POSIX, ",posix", "" },
                { NFS_MOUNT_NOCTO, ",nocto", "" },
                { NFS_MOUNT_NOAC, ",noac", "" },
                { NFS_MOUNT_NONLM, ",nolock", "" },
                { NFS_MOUNT_NOACL, ",noacl", "" },
                { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
+               { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
                { 0, NULL, NULL }
        };
        const struct proc_nfs_info *nfs_infop;
        struct nfs_client *clp = nfss->nfs_client;
-       char buf[12];
-       const char *proto;
-
-       seq_printf(m, ",vers=%d", clp->rpc_ops->version);
-       seq_printf(m, ",rsize=%d", nfss->rsize);
-       seq_printf(m, ",wsize=%d", nfss->wsize);
+       u32 version = clp->rpc_ops->version;
+
+       seq_printf(m, ",vers=%u", version);
+       seq_printf(m, ",rsize=%u", nfss->rsize);
+       seq_printf(m, ",wsize=%u", nfss->wsize);
+       if (nfss->bsize != 0)
+               seq_printf(m, ",bsize=%u", nfss->bsize);
+       seq_printf(m, ",namlen=%u", nfss->namelen);
        if (nfss->acregmin != 3*HZ || showdefaults)
-               seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
+               seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
        if (nfss->acregmax != 60*HZ || showdefaults)
-               seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
+               seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
        if (nfss->acdirmin != 30*HZ || showdefaults)
-               seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
+               seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
        if (nfss->acdirmax != 60*HZ || showdefaults)
-               seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
+               seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
        for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
                if (nfss->flags & nfs_infop->flag)
                        seq_puts(m, nfs_infop->str);
                else
                        seq_puts(m, nfs_infop->nostr);
        }
-       switch (nfss->client->cl_xprt->prot) {
-               case IPPROTO_TCP:
-                       proto = "tcp";
-                       break;
-               case IPPROTO_UDP:
-                       proto = "udp";
-                       break;
-               default:
-                       snprintf(buf, sizeof(buf), "%u", nfss->client->cl_xprt->prot);
-                       proto = buf;
-       }
-       seq_printf(m, ",proto=%s", proto);
-       seq_printf(m, ",timeo=%lu", 10U * clp->retrans_timeo / HZ);
-       seq_printf(m, ",retrans=%u", clp->retrans_count);
+       seq_printf(m, ",proto=%s",
+                  rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
+       if (version == 4) {
+               if (nfss->port != NFS_PORT)
+                       seq_printf(m, ",port=%u", nfss->port);
+       } else
+               if (nfss->port)
+                       seq_printf(m, ",port=%u", nfss->port);
+
+       seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
+       seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
        seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
+
+       if (version != 4)
+               nfs_show_mountd_options(m, nfss, showdefaults);
+
+#ifdef CONFIG_NFS_V4
+       if (clp->rpc_ops->version == 4)
+               seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
+#endif
 }
 
 /*
@@ -341,8 +562,9 @@ static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 
        nfs_show_mount_options(m, nfss, 0);
 
-       seq_puts(m, ",addr=");
-       seq_escape(m, nfss->nfs_client->cl_hostname, " \t\n\\");
+       seq_printf(m, ",addr=%s",
+                       rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
+                                                       RPC_DISPLAY_ADDR));
 
        return 0;
 }
@@ -373,13 +595,13 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 
        seq_printf(m, "\n\tcaps:\t");
        seq_printf(m, "caps=0x%x", nfss->caps);
-       seq_printf(m, ",wtmult=%d", nfss->wtmult);
-       seq_printf(m, ",dtsize=%d", nfss->dtsize);
-       seq_printf(m, ",bsize=%d", nfss->bsize);
-       seq_printf(m, ",namelen=%d", nfss->namelen);
+       seq_printf(m, ",wtmult=%u", nfss->wtmult);
+       seq_printf(m, ",dtsize=%u", nfss->dtsize);
+       seq_printf(m, ",bsize=%u", nfss->bsize);
+       seq_printf(m, ",namlen=%u", nfss->namelen);
 
 #ifdef CONFIG_NFS_V4
-       if (nfss->nfs_client->cl_nfsversion == 4) {
+       if (nfss->nfs_client->rpc_ops->version == 4) {
                seq_printf(m, "\n\tnfsv4:\t");
                seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
                seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
@@ -390,9 +612,9 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
        /*
         * Display security flavor in effect for this mount
         */
-       seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
+       seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
        if (auth->au_flavor)
-               seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
+               seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
 
        /*
         * Display superblock I/O counters
@@ -428,15 +650,11 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
  * Begin unmount by attempting to remove all automounted mountpoints we added
  * in response to xdev traversals and referrals
  */
-static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
+static void nfs_umount_begin(struct super_block *sb)
 {
-       struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
+       struct nfs_server *server = NFS_SB(sb);
        struct rpc_clnt *rpc;
 
-       shrink_submounts(vfsmnt, &nfs_automount_list);
-
-       if (!(flags & MNT_FORCE))
-               return;
        /* -EIO all pending I/O */
        rpc = server->client_acl;
        if (!IS_ERR(rpc))
@@ -447,16 +665,40 @@ static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
 }
 
 /*
- * Sanity-check a server address provided by the mount command
+ * Set the port number in an address.  Be agnostic about the address family.
+ */
+static void nfs_set_port(struct sockaddr *sap, unsigned short port)
+{
+       switch (sap->sa_family) {
+       case AF_INET: {
+               struct sockaddr_in *ap = (struct sockaddr_in *)sap;
+               ap->sin_port = htons(port);
+               break;
+       }
+       case AF_INET6: {
+               struct sockaddr_in6 *ap = (struct sockaddr_in6 *)sap;
+               ap->sin6_port = htons(port);
+               break;
+       }
+       }
+}
+
+/*
+ * Sanity-check a server address provided by the mount command.
+ *
+ * Address family must be initialized, and address must not be
+ * the ANY address for that family.
  */
 static int nfs_verify_server_address(struct sockaddr *addr)
 {
        switch (addr->sa_family) {
        case AF_INET: {
-               struct sockaddr_in *sa = (struct sockaddr_in *) addr;
-               if (sa->sin_addr.s_addr != INADDR_ANY)
-                       return 1;
-               break;
+               struct sockaddr_in *sa = (struct sockaddr_in *)addr;
+               return sa->sin_addr.s_addr != htonl(INADDR_ANY);
+       }
+       case AF_INET6: {
+               struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
+               return !ipv6_addr_any(sa);
        }
        }
 
@@ -464,15 +706,535 @@ static int nfs_verify_server_address(struct sockaddr *addr)
 }
 
 /*
+ * Parse string addresses passed in via a mount option,
+ * and construct a sockaddr based on the result.
+ *
+ * If address parsing fails, set the sockaddr's address
+ * family to AF_UNSPEC to force nfs_verify_server_address()
+ * to punt the mount.
+ */
+static void nfs_parse_server_address(char *value,
+                                    struct sockaddr *sap,
+                                    size_t *len)
+{
+       if (strchr(value, ':')) {
+               struct sockaddr_in6 *ap = (struct sockaddr_in6 *)sap;
+               u8 *addr = (u8 *)&ap->sin6_addr.in6_u;
+
+               ap->sin6_family = AF_INET6;
+               *len = sizeof(*ap);
+               if (in6_pton(value, -1, addr, '\0', NULL))
+                       return;
+       } else {
+               struct sockaddr_in *ap = (struct sockaddr_in *)sap;
+               u8 *addr = (u8 *)&ap->sin_addr.s_addr;
+
+               ap->sin_family = AF_INET;
+               *len = sizeof(*ap);
+               if (in4_pton(value, -1, addr, '\0', NULL))
+                       return;
+       }
+
+       sap->sa_family = AF_UNSPEC;
+       *len = 0;
+}
+
+/*
+ * Error-check and convert a string of mount options from user space into
+ * a data structure
+ */
+static int nfs_parse_mount_options(char *raw,
+                                  struct nfs_parsed_mount_data *mnt)
+{
+       char *p, *string, *secdata;
+       int rc;
+
+       if (!raw) {
+               dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
+               return 1;
+       }
+       dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
+
+       secdata = alloc_secdata();
+       if (!secdata)
+               goto out_nomem;
+
+       rc = security_sb_copy_data(raw, secdata);
+       if (rc)
+               goto out_security_failure;
+
+       rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
+       if (rc)
+               goto out_security_failure;
+
+       free_secdata(secdata);
+
+       while ((p = strsep(&raw, ",")) != NULL) {
+               substring_t args[MAX_OPT_ARGS];
+               int option, token;
+
+               if (!*p)
+                       continue;
+
+               dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
+
+               token = match_token(p, nfs_mount_option_tokens, args);
+               switch (token) {
+               case Opt_soft:
+                       mnt->flags |= NFS_MOUNT_SOFT;
+                       break;
+               case Opt_hard:
+                       mnt->flags &= ~NFS_MOUNT_SOFT;
+                       break;
+               case Opt_posix:
+                       mnt->flags |= NFS_MOUNT_POSIX;
+                       break;
+               case Opt_noposix:
+                       mnt->flags &= ~NFS_MOUNT_POSIX;
+                       break;
+               case Opt_cto:
+                       mnt->flags &= ~NFS_MOUNT_NOCTO;
+                       break;
+               case Opt_nocto:
+                       mnt->flags |= NFS_MOUNT_NOCTO;
+                       break;
+               case Opt_ac:
+                       mnt->flags &= ~NFS_MOUNT_NOAC;
+                       break;
+               case Opt_noac:
+                       mnt->flags |= NFS_MOUNT_NOAC;
+                       break;
+               case Opt_lock:
+                       mnt->flags &= ~NFS_MOUNT_NONLM;
+                       break;
+               case Opt_nolock:
+                       mnt->flags |= NFS_MOUNT_NONLM;
+                       break;
+               case Opt_v2:
+                       mnt->flags &= ~NFS_MOUNT_VER3;
+                       break;
+               case Opt_v3:
+                       mnt->flags |= NFS_MOUNT_VER3;
+                       break;
+               case Opt_udp:
+                       mnt->flags &= ~NFS_MOUNT_TCP;
+                       mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+                       mnt->timeo = 7;
+                       mnt->retrans = 5;
+                       break;
+               case Opt_tcp:
+                       mnt->flags |= NFS_MOUNT_TCP;
+                       mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+                       mnt->timeo = 600;
+                       mnt->retrans = 2;
+                       break;
+               case Opt_rdma:
+                       mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
+                       mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
+                       mnt->timeo = 600;
+                       mnt->retrans = 2;
+                       break;
+               case Opt_acl:
+                       mnt->flags &= ~NFS_MOUNT_NOACL;
+                       break;
+               case Opt_noacl:
+                       mnt->flags |= NFS_MOUNT_NOACL;
+                       break;
+               case Opt_rdirplus:
+                       mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
+                       break;
+               case Opt_nordirplus:
+                       mnt->flags |= NFS_MOUNT_NORDIRPLUS;
+                       break;
+               case Opt_sharecache:
+                       mnt->flags &= ~NFS_MOUNT_UNSHARED;
+                       break;
+               case Opt_nosharecache:
+                       mnt->flags |= NFS_MOUNT_UNSHARED;
+                       break;
+
+               case Opt_port:
+                       if (match_int(args, &option))
+                               return 0;
+                       if (option < 0 || option > 65535)
+                               return 0;
+                       mnt->nfs_server.port = option;
+                       break;
+               case Opt_rsize:
+                       if (match_int(args, &mnt->rsize))
+                               return 0;
+                       break;
+               case Opt_wsize:
+                       if (match_int(args, &mnt->wsize))
+                               return 0;
+                       break;
+               case Opt_bsize:
+                       if (match_int(args, &option))
+                               return 0;
+                       if (option < 0)
+                               return 0;
+                       mnt->bsize = option;
+                       break;
+               case Opt_timeo:
+                       if (match_int(args, &mnt->timeo))
+                               return 0;
+                       break;
+               case Opt_retrans:
+                       if (match_int(args, &mnt->retrans))
+                               return 0;
+                       break;
+               case Opt_acregmin:
+                       if (match_int(args, &mnt->acregmin))
+                               return 0;
+                       break;
+               case Opt_acregmax:
+                       if (match_int(args, &mnt->acregmax))
+                               return 0;
+                       break;
+               case Opt_acdirmin:
+                       if (match_int(args, &mnt->acdirmin))
+                               return 0;
+                       break;
+               case Opt_acdirmax:
+                       if (match_int(args, &mnt->acdirmax))
+                               return 0;
+                       break;
+               case Opt_actimeo:
+                       if (match_int(args, &option))
+                               return 0;
+                       if (option < 0)
+                               return 0;
+                       mnt->acregmin =
+                       mnt->acregmax =
+                       mnt->acdirmin =
+                       mnt->acdirmax = option;
+                       break;
+               case Opt_namelen:
+                       if (match_int(args, &mnt->namlen))
+                               return 0;
+                       break;
+               case Opt_mountport:
+                       if (match_int(args, &option))
+                               return 0;
+                       if (option < 0 || option > 65535)
+                               return 0;
+                       mnt->mount_server.port = option;
+                       break;
+               case Opt_mountvers:
+                       if (match_int(args, &option))
+                               return 0;
+                       if (option < 0)
+                               return 0;
+                       mnt->mount_server.version = option;
+                       break;
+               case Opt_nfsvers:
+                       if (match_int(args, &option))
+                               return 0;
+                       switch (option) {
+                       case 2:
+                               mnt->flags &= ~NFS_MOUNT_VER3;
+                               break;
+                       case 3:
+                               mnt->flags |= NFS_MOUNT_VER3;
+                               break;
+                       default:
+                               goto out_unrec_vers;
+                       }
+                       break;
+
+               case Opt_sec:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       token = match_token(string, nfs_secflavor_tokens, args);
+                       kfree(string);
+
+                       /*
+                        * The flags setting is for v2/v3.  The flavor_len
+                        * setting is for v4.  v2/v3 also need to know the
+                        * difference between NULL and UNIX.
+                        */
+                       switch (token) {
+                       case Opt_sec_none:
+                               mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 0;
+                               mnt->auth_flavors[0] = RPC_AUTH_NULL;
+                               break;
+                       case Opt_sec_sys:
+                               mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 0;
+                               mnt->auth_flavors[0] = RPC_AUTH_UNIX;
+                               break;
+                       case Opt_sec_krb5:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
+                               break;
+                       case Opt_sec_krb5i:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
+                               break;
+                       case Opt_sec_krb5p:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
+                               break;
+                       case Opt_sec_lkey:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
+                               break;
+                       case Opt_sec_lkeyi:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
+                               break;
+                       case Opt_sec_lkeyp:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
+                               break;
+                       case Opt_sec_spkm:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
+                               break;
+                       case Opt_sec_spkmi:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
+                               break;
+                       case Opt_sec_spkmp:
+                               mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+                               mnt->auth_flavor_len = 1;
+                               mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
+                               break;
+                       default:
+                               goto out_unrec_sec;
+                       }
+                       break;
+               case Opt_proto:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       token = match_token(string,
+                                           nfs_xprt_protocol_tokens, args);
+                       kfree(string);
+
+                       switch (token) {
+                       case Opt_xprt_udp:
+                               mnt->flags &= ~NFS_MOUNT_TCP;
+                               mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+                               mnt->timeo = 7;
+                               mnt->retrans = 5;
+                               break;
+                       case Opt_xprt_tcp:
+                               mnt->flags |= NFS_MOUNT_TCP;
+                               mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+                               mnt->timeo = 600;
+                               mnt->retrans = 2;
+                               break;
+                       case Opt_xprt_rdma:
+                               /* vector side protocols to TCP */
+                               mnt->flags |= NFS_MOUNT_TCP;
+                               mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
+                               mnt->timeo = 600;
+                               mnt->retrans = 2;
+                               break;
+                       default:
+                               goto out_unrec_xprt;
+                       }
+                       break;
+               case Opt_mountproto:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       token = match_token(string,
+                                           nfs_xprt_protocol_tokens, args);
+                       kfree(string);
+
+                       switch (token) {
+                       case Opt_xprt_udp:
+                               mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
+                               break;
+                       case Opt_xprt_tcp:
+                               mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
+                               break;
+                       case Opt_xprt_rdma: /* not used for side protocols */
+                       default:
+                               goto out_unrec_xprt;
+                       }
+                       break;
+               case Opt_addr:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       nfs_parse_server_address(string, (struct sockaddr *)
+                                                &mnt->nfs_server.address,
+                                                &mnt->nfs_server.addrlen);
+                       kfree(string);
+                       break;
+               case Opt_clientaddr:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       kfree(mnt->client_address);
+                       mnt->client_address = string;
+                       break;
+               case Opt_mounthost:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       kfree(mnt->mount_server.hostname);
+                       mnt->mount_server.hostname = string;
+                       break;
+               case Opt_mountaddr:
+                       string = match_strdup(args);
+                       if (string == NULL)
+                               goto out_nomem;
+                       nfs_parse_server_address(string, (struct sockaddr *)
+                                                &mnt->mount_server.address,
+                                                &mnt->mount_server.addrlen);
+                       kfree(string);
+                       break;
+
+               case Opt_userspace:
+               case Opt_deprecated:
+                       dfprintk(MOUNT, "NFS:   ignoring mount option "
+                                       "'%s'\n", p);
+                       break;
+
+               default:
+                       goto out_unknown;
+               }
+       }
+
+       nfs_set_port((struct sockaddr *)&mnt->nfs_server.address,
+                               mnt->nfs_server.port);
+
+       return 1;
+
+out_nomem:
+       printk(KERN_INFO "NFS: not enough memory to parse option\n");
+       return 0;
+out_security_failure:
+       free_secdata(secdata);
+       printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
+       return 0;
+out_unrec_vers:
+       printk(KERN_INFO "NFS: unrecognized NFS version number\n");
+       return 0;
+
+out_unrec_xprt:
+       printk(KERN_INFO "NFS: unrecognized transport protocol\n");
+       return 0;
+
+out_unrec_sec:
+       printk(KERN_INFO "NFS: unrecognized security flavor\n");
+       return 0;
+
+out_unknown:
+       printk(KERN_INFO "NFS: unknown mount option: %s\n", p);
+       return 0;
+}
+
+/*
+ * Use the remote server's MOUNT service to request the NFS file handle
+ * corresponding to the provided path.
+ */
+static int nfs_try_mount(struct nfs_parsed_mount_data *args,
+                        struct nfs_fh *root_fh)
+{
+       struct sockaddr *sap = (struct sockaddr *)&args->mount_server.address;
+       char *hostname;
+       int status;
+
+       if (args->mount_server.version == 0) {
+               if (args->flags & NFS_MOUNT_VER3)
+                       args->mount_server.version = NFS_MNT3_VERSION;
+               else
+                       args->mount_server.version = NFS_MNT_VERSION;
+       }
+
+       if (args->mount_server.hostname)
+               hostname = args->mount_server.hostname;
+       else
+               hostname = args->nfs_server.hostname;
+
+       /*
+        * Construct the mount server's address.
+        */
+       if (args->mount_server.address.ss_family == AF_UNSPEC) {
+               memcpy(sap, &args->nfs_server.address,
+                      args->nfs_server.addrlen);
+               args->mount_server.addrlen = args->nfs_server.addrlen;
+       }
+
+       /*
+        * autobind will be used if mount_server.port == 0
+        */
+       nfs_set_port(sap, args->mount_server.port);
+
+       /*
+        * Now ask the mount server to map our export path
+        * to a file handle.
+        */
+       status = nfs_mount(sap,
+                          args->mount_server.addrlen,
+                          hostname,
+                          args->nfs_server.export_path,
+                          args->mount_server.version,
+                          args->mount_server.protocol,
+                          root_fh);
+       if (status == 0)
+               return 0;
+
+       dfprintk(MOUNT, "NFS: unable to mount server %s, error %d",
+                       hostname, status);
+       return status;
+}
+
+/*
  * Validate the NFS2/NFS3 mount data
  * - fills in the mount root filehandle
+ *
+ * For option strings, user space handles the following behaviors:
+ *
+ * + DNS: mapping server host name to IP address ("addr=" option)
+ *
+ * + failure mode: how to behave if a mount request can't be handled
+ *   immediately ("fg/bg" option)
+ *
+ * + retry: how often to retry a mount request ("retry=" option)
+ *
+ * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
+ *   mountproto=tcp after mountproto=udp, and so on
  */
-static int nfs_validate_mount_data(struct nfs_mount_data *data,
-                                  struct nfs_fh *mntfh)
+static int nfs_validate_mount_data(void *options,
+                                  struct nfs_parsed_mount_data *args,
+                                  struct nfs_fh *mntfh,
+                                  const char *dev_name)
 {
+       struct nfs_mount_data *data = (struct nfs_mount_data *)options;
+
        if (data == NULL)
                goto out_no_data;
 
+       args->flags             = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
+       args->rsize             = NFS_MAX_FILE_IO_SIZE;
+       args->wsize             = NFS_MAX_FILE_IO_SIZE;
+       args->timeo             = 600;
+       args->retrans           = 2;
+       args->acregmin          = 3;
+       args->acregmax          = 60;
+       args->acdirmin          = 30;
+       args->acdirmax          = 60;
+       args->mount_server.port = 0;    /* autobind unless user sets port */
+       args->mount_server.protocol = XPRT_TRANSPORT_UDP;
+       args->nfs_server.port   = 0;    /* autobind unless user sets port */
+       args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+
        switch (data->version) {
        case 1:
                data->namlen = 0;
@@ -489,34 +1251,119 @@ static int nfs_validate_mount_data(struct nfs_mount_data *data,
        case 5:
                memset(data->context, 0, sizeof(data->context));
        case 6:
-               if (data->flags & NFS_MOUNT_VER3)
+               if (data->flags & NFS_MOUNT_VER3) {
+                       if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
+                               goto out_invalid_fh;
                        mntfh->size = data->root.size;
-               else
+               else
                        mntfh->size = NFS2_FHSIZE;
 
-               if (mntfh->size > sizeof(mntfh->data))
-                       goto out_invalid_fh;
 
                memcpy(mntfh->data, data->root.data, mntfh->size);
                if (mntfh->size < sizeof(mntfh->data))
                        memset(mntfh->data + mntfh->size, 0,
                               sizeof(mntfh->data) - mntfh->size);
+
+               /*
+                * Translate to nfs_parsed_mount_data, which nfs_fill_super
+                * can deal with.
+                */
+               args->flags             = data->flags;
+               args->rsize             = data->rsize;
+               args->wsize             = data->wsize;
+               args->timeo             = data->timeo;
+               args->retrans           = data->retrans;
+               args->acregmin          = data->acregmin;
+               args->acregmax          = data->acregmax;
+               args->acdirmin          = data->acdirmin;
+               args->acdirmax          = data->acdirmax;
+
+               memcpy(&args->nfs_server.address, &data->addr,
+                      sizeof(data->addr));
+               args->nfs_server.addrlen = sizeof(data->addr);
+               if (!nfs_verify_server_address((struct sockaddr *)
+                                               &args->nfs_server.address))
+                       goto out_no_address;
+
+               if (!(data->flags & NFS_MOUNT_TCP))
+                       args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+               /* N.B. caller will free nfs_server.hostname in all cases */
+               args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
+               args->namlen            = data->namlen;
+               args->bsize             = data->bsize;
+               args->auth_flavors[0]   = data->pseudoflavor;
+               if (!args->nfs_server.hostname)
+                       goto out_nomem;
+
+               /*
+                * The legacy version 6 binary mount data from userspace has a
+                * field used only to transport selinux information into the
+                * the kernel.  To continue to support that functionality we
+                * have a touch of selinux knowledge here in the NFS code. The
+                * userspace code converted context=blah to just blah so we are
+                * converting back to the full string selinux understands.
+                */
+               if (data->context[0]){
+#ifdef CONFIG_SECURITY_SELINUX
+                       int rc;
+                       char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
+                       if (!opts_str)
+                               return -ENOMEM;
+                       strcpy(opts_str, "context=");
+                       data->context[NFS_MAX_CONTEXT_LEN] = '\0';
+                       strcat(opts_str, &data->context[0]);
+                       rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
+                       kfree(opts_str);
+                       if (rc)
+                               return rc;
+#else
+                       return -EINVAL;
+#endif
+               }
+
                break;
-       default:
-               goto out_bad_version;
+       default: {
+               unsigned int len;
+               char *c;
+               int status;
+
+               if (nfs_parse_mount_options((char *)options, args) == 0)
+                       return -EINVAL;
+
+               if (!nfs_verify_server_address((struct sockaddr *)
+                                               &args->nfs_server.address))
+                       goto out_no_address;
+
+               c = strchr(dev_name, ':');
+               if (c == NULL)
+                       return -EINVAL;
+               len = c - dev_name;
+               /* N.B. caller will free nfs_server.hostname in all cases */
+               args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
+               if (!args->nfs_server.hostname)
+                       goto out_nomem;
+
+               c++;
+               if (strlen(c) > NFS_MAXPATHLEN)
+                       return -ENAMETOOLONG;
+               args->nfs_server.export_path = c;
+
+               status = nfs_try_mount(args, mntfh);
+               if (status)
+                       return status;
+
+               break;
+               }
        }
 
-       if (!(data->flags & NFS_MOUNT_SECFLAVOUR))
-               data->pseudoflavor = RPC_AUTH_UNIX;
+       if (!(args->flags & NFS_MOUNT_SECFLAVOUR))
+               args->auth_flavors[0] = RPC_AUTH_UNIX;
 
 #ifndef CONFIG_NFS_V3
-       if (data->flags & NFS_MOUNT_VER3)
+       if (args->flags & NFS_MOUNT_VER3)
                goto out_v3_not_compiled;
 #endif /* !CONFIG_NFS_V3 */
 
-       if (!nfs_verify_server_address((struct sockaddr *) &data->addr))
-               goto out_no_address;
-
        return 0;
 
 out_no_data:
@@ -532,17 +1379,16 @@ out_no_sec:
        dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
        return -EINVAL;
 
-out_bad_version:
-       dfprintk(MOUNT, "NFS: bad nfs_mount_data version %d\n",
-                data->version);
-       return -EINVAL;
-
 #ifndef CONFIG_NFS_V3
 out_v3_not_compiled:
        dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
        return -EPROTONOSUPPORT;
 #endif /* !CONFIG_NFS_V3 */
 
+out_nomem:
+       dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
+       return -ENOMEM;
+
 out_no_address:
        dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
        return -EINVAL;
@@ -552,6 +1398,79 @@ out_invalid_fh:
        return -EINVAL;
 }
 
+static int
+nfs_compare_remount_data(struct nfs_server *nfss,
+                        struct nfs_parsed_mount_data *data)
+{
+       if (data->flags != nfss->flags ||
+           data->rsize != nfss->rsize ||
+           data->wsize != nfss->wsize ||
+           data->retrans != nfss->client->cl_timeout->to_retries ||
+           data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
+           data->acregmin != nfss->acregmin / HZ ||
+           data->acregmax != nfss->acregmax / HZ ||
+           data->acdirmin != nfss->acdirmin / HZ ||
+           data->acdirmax != nfss->acdirmax / HZ ||
+           data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
+           data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
+           memcmp(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
+                  data->nfs_server.addrlen) != 0)
+               return -EINVAL;
+
+       return 0;
+}
+
+static int
+nfs_remount(struct super_block *sb, int *flags, char *raw_data)
+{
+       int error;
+       struct nfs_server *nfss = sb->s_fs_info;
+       struct nfs_parsed_mount_data *data;
+       struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
+       struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
+
+       /*
+        * Userspace mount programs that send binary options generally send
+        * them populated with default values. We have no way to know which
+        * ones were explicitly specified. Fall back to legacy behavior and
+        * just return success.
+        */
+       if ((sb->s_type == &nfs4_fs_type && options4->version == 1) ||
+           (sb->s_type == &nfs_fs_type && options->version >= 1 &&
+            options->version <= 6))
+               return 0;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (data == NULL)
+               return -ENOMEM;
+
+       /* fill out struct with values from existing mount */
+       data->flags = nfss->flags;
+       data->rsize = nfss->rsize;
+       data->wsize = nfss->wsize;
+       data->retrans = nfss->client->cl_timeout->to_retries;
+       data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
+       data->acregmin = nfss->acregmin / HZ;
+       data->acregmax = nfss->acregmax / HZ;
+       data->acdirmin = nfss->acdirmin / HZ;
+       data->acdirmax = nfss->acdirmax / HZ;
+       data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
+       data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
+       memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
+               data->nfs_server.addrlen);
+
+       /* overwrite those values with any that were specified */
+       error = nfs_parse_mount_options((char *)options, data);
+       if (error < 0)
+               goto out;
+
+       /* compare new mount options with old ones */
+       error = nfs_compare_remount_data(nfss, data);
+out:
+       kfree(data);
+       return error;
+}
+
 /*
  * Initialise the common bits of the superblock
  */
@@ -578,7 +1497,8 @@ static inline void nfs_initialise_sb(struct super_block *sb)
 /*
  * Finish setting up an NFS2/3 superblock
  */
-static void nfs_fill_super(struct super_block *sb, struct nfs_mount_data *data)
+static void nfs_fill_super(struct super_block *sb,
+                          struct nfs_parsed_mount_data *data)
 {
        struct nfs_server *server = NFS_SB(sb);
 
@@ -623,11 +1543,51 @@ static void nfs_clone_super(struct super_block *sb,
        nfs_initialise_sb(sb);
 }
 
-static int nfs_set_super(struct super_block *s, void *_server)
+#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
+
+static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
+{
+       const struct nfs_server *a = s->s_fs_info;
+       const struct rpc_clnt *clnt_a = a->client;
+       const struct rpc_clnt *clnt_b = b->client;
+
+       if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
+               goto Ebusy;
+       if (a->nfs_client != b->nfs_client)
+               goto Ebusy;
+       if (a->flags != b->flags)
+               goto Ebusy;
+       if (a->wsize != b->wsize)
+               goto Ebusy;
+       if (a->rsize != b->rsize)
+               goto Ebusy;
+       if (a->acregmin != b->acregmin)
+               goto Ebusy;
+       if (a->acregmax != b->acregmax)
+               goto Ebusy;
+       if (a->acdirmin != b->acdirmin)
+               goto Ebusy;
+       if (a->acdirmax != b->acdirmax)
+               goto Ebusy;
+       if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
+               goto Ebusy;
+       return 1;
+Ebusy:
+       return 0;
+}
+
+struct nfs_sb_mountdata {
+       struct nfs_server *server;
+       int mntflags;
+};
+
+static int nfs_set_super(struct super_block *s, void *data)
 {
-       struct nfs_server *server = _server;
+       struct nfs_sb_mountdata *sb_mntdata = data;
+       struct nfs_server *server = sb_mntdata->server;
        int ret;
 
+       s->s_flags = sb_mntdata->mntflags;
        s->s_fs_info = server;
        ret = set_anon_super(s, server);
        if (ret == 0)
@@ -635,15 +1595,62 @@ static int nfs_set_super(struct super_block *s, void *_server)
        return ret;
 }
 
+static int nfs_compare_super_address(struct nfs_server *server1,
+                                    struct nfs_server *server2)
+{
+       struct sockaddr *sap1, *sap2;
+
+       sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
+       sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
+
+       if (sap1->sa_family != sap2->sa_family)
+               return 0;
+
+       switch (sap1->sa_family) {
+       case AF_INET: {
+               struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
+               struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
+               if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
+                       return 0;
+               if (sin1->sin_port != sin2->sin_port)
+                       return 0;
+               break;
+       }
+       case AF_INET6: {
+               struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
+               struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
+               if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
+                       return 0;
+               if (sin1->sin6_port != sin2->sin6_port)
+                       return 0;
+               break;
+       }
+       default:
+               return 0;
+       }
+
+       return 1;
+}
+
 static int nfs_compare_super(struct super_block *sb, void *data)
 {
-       struct nfs_server *server = data, *old = NFS_SB(sb);
+       struct nfs_sb_mountdata *sb_mntdata = data;
+       struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
+       int mntflags = sb_mntdata->mntflags;
 
-       if (old->nfs_client != server->nfs_client)
+       if (!nfs_compare_super_address(old, server))
+               return 0;
+       /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
+       if (old->flags & NFS_MOUNT_UNSHARED)
                return 0;
        if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
                return 0;
-       return 1;
+       return nfs_compare_mount_options(sb, server, mntflags);
+}
+
+static int nfs_bdi_register(struct nfs_server *server)
+{
+       return bdi_register_dev(&server->backing_dev_info, server->s_dev);
 }
 
 static int nfs_get_sb(struct file_system_type *fs_type,
@@ -651,25 +1658,40 @@ static int nfs_get_sb(struct file_system_type *fs_type,
 {
        struct nfs_server *server = NULL;
        struct super_block *s;
-       struct nfs_fh mntfh;
-       struct nfs_mount_data *data = raw_data;
+       struct nfs_parsed_mount_data *data;
+       struct nfs_fh *mntfh;
        struct dentry *mntroot;
-       int error;
+       int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+       struct nfs_sb_mountdata sb_mntdata = {
+               .mntflags = flags,
+       };
+       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 = nfs_validate_mount_data(data, &mntfh);
+       error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
        if (error < 0)
                goto out;
 
        /* Get a volume representation */
-       server = nfs_create_server(data, &mntfh);
+       server = nfs_create_server(data, mntfh);
        if (IS_ERR(server)) {
                error = PTR_ERR(server);
                goto out;
        }
+       sb_mntdata.server = server;
+
+       if (server->flags & NFS_MOUNT_UNSHARED)
+               compare_super = NULL;
 
        /* Get a superblock - note that we may end up sharing one that already exists */
-       s = sget(fs_type, nfs_compare_super, nfs_set_super, server);
+       s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto out_err_nosb;
@@ -678,32 +1700,47 @@ static int nfs_get_sb(struct file_system_type *fs_type,
        if (s->s_fs_info != server) {
                nfs_free_server(server);
                server = NULL;
+       } else {
+               error = nfs_bdi_register(server);
+               if (error)
+                       goto error_splat_super;
        }
 
        if (!s->s_root) {
                /* initial superblock/root creation */
-               s->s_flags = flags;
                nfs_fill_super(s, data);
        }
 
-       mntroot = nfs_get_root(s, &mntfh);
+       mntroot = nfs_get_root(s, mntfh);
        if (IS_ERR(mntroot)) {
                error = PTR_ERR(mntroot);
                goto error_splat_super;
        }
 
+       error = security_sb_set_mnt_opts(s, &data->lsm_opts);
+       if (error)
+               goto error_splat_root;
+
        s->s_flags |= MS_ACTIVE;
        mnt->mnt_sb = s;
        mnt->mnt_root = mntroot;
        error = 0;
 
 out:
+       kfree(data->nfs_server.hostname);
+       kfree(data->mount_server.hostname);
+       security_free_mnt_opts(&data->lsm_opts);
+out_free_fh:
+       kfree(mntfh);
+       kfree(data);
        return error;
 
 out_err_nosb:
        nfs_free_server(server);
        goto out;
 
+error_splat_root:
+       dput(mntroot);
 error_splat_super:
        up_write(&s->s_umount);
        deactivate_super(s);
@@ -717,6 +1754,7 @@ static void nfs_kill_super(struct super_block *s)
 {
        struct nfs_server *server = NFS_SB(s);
 
+       bdi_unregister(&server->backing_dev_info);
        kill_anon_super(s);
        nfs_free_server(server);
 }
@@ -732,6 +1770,10 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
        struct super_block *s;
        struct nfs_server *server;
        struct dentry *mntroot;
+       int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+       struct nfs_sb_mountdata sb_mntdata = {
+               .mntflags = flags,
+       };
        int error;
 
        dprintk("--> nfs_xdev_get_sb()\n");
@@ -742,9 +1784,13 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
                error = PTR_ERR(server);
                goto out_err_noserver;
        }
+       sb_mntdata.server = server;
+
+       if (server->flags & NFS_MOUNT_UNSHARED)
+               compare_super = NULL;
 
        /* Get a superblock - note that we may end up sharing one that already exists */
-       s = sget(&nfs_fs_type, nfs_compare_super, nfs_set_super, server);
+       s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto out_err_nosb;
@@ -753,11 +1799,14 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
        if (s->s_fs_info != server) {
                nfs_free_server(server);
                server = NULL;
+       } else {
+               error = nfs_bdi_register(server);
+               if (error)
+                       goto error_splat_super;
        }
 
        if (!s->s_root) {
                /* initial superblock/root creation */
-               s->s_flags = flags;
                nfs_clone_super(s, data->sb);
        }
 
@@ -766,11 +1815,19 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
                error = PTR_ERR(mntroot);
                goto error_splat_super;
        }
+       if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+               dput(mntroot);
+               error = -ESTALE;
+               goto error_splat_super;
+       }
 
        s->s_flags |= MS_ACTIVE;
        mnt->mnt_sb = s;
        mnt->mnt_root = mntroot;
 
+       /* clone any lsm security options from the parent to the new sb */
+       security_sb_clone_mnt_opts(data->sb, s);
+
        dprintk("<-- nfs_xdev_get_sb() = 0\n");
        return 0;
 
@@ -814,91 +1871,209 @@ static void nfs4_fill_super(struct super_block *sb)
 }
 
 /*
- * Get the superblock for an NFS4 mountpoint
+ * Validate NFSv4 mount options
  */
-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_validate_mount_data(void *options,
+                                   struct nfs_parsed_mount_data *args,
+                                   const char *dev_name)
 {
-       struct nfs4_mount_data *data = raw_data;
-       struct super_block *s;
-       struct nfs_server *server;
-       struct sockaddr_in addr;
-       rpc_authflavor_t authflavour;
-       struct nfs_fh mntfh;
-       struct dentry *mntroot;
-       char *p, *mntpath = NULL, *hostname = NULL, *ip_addr = NULL;
-       int error;
+       struct sockaddr_in *ap;
+       struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
+       char *c;
 
-       if (data == NULL) {
-               dprintk("%s: missing data argument\n", __FUNCTION__);
-               return -EINVAL;
-       }
-       if (data->version <= 0 || data->version > NFS4_MOUNT_VERSION) {
-               dprintk("%s: bad mount version\n", __FUNCTION__);
-               return -EINVAL;
-       }
+       if (data == NULL)
+               goto out_no_data;
 
-       /* We now require that the mount process passes the remote address */
-       if (data->host_addrlen != sizeof(addr))
-               return -EINVAL;
+       args->rsize             = NFS_MAX_FILE_IO_SIZE;
+       args->wsize             = NFS_MAX_FILE_IO_SIZE;
+       args->timeo             = 600;
+       args->retrans           = 2;
+       args->acregmin          = 3;
+       args->acregmax          = 60;
+       args->acdirmin          = 30;
+       args->acdirmax          = 60;
+       args->nfs_server.port   = NFS_PORT; /* 2049 unless user set port= */
+       args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 
-       if (copy_from_user(&addr, data->host_addr, sizeof(addr)))
-               return -EFAULT;
+       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))
+                       return -EFAULT;
+               if (!nfs_verify_server_address((struct sockaddr *)
+                                               &args->nfs_server.address))
+                       goto out_no_address;
+
+               switch (data->auth_flavourlen) {
+               case 0:
+                       args->auth_flavors[0] = RPC_AUTH_UNIX;
+                       break;
+               case 1:
+                       if (copy_from_user(&args->auth_flavors[0],
+                                          data->auth_flavours,
+                                          sizeof(args->auth_flavors[0])))
+                               return -EFAULT;
+                       break;
+               default:
+                       goto out_inval_auth;
+               }
 
-       if (!nfs_verify_server_address((struct sockaddr *) &addr)) {
-               dprintk("%s: mount program didn't pass remote IP address!\n",
-                               __FUNCTION__);
-               return -EINVAL;
-       }
+               c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
+               if (IS_ERR(c))
+                       return PTR_ERR(c);
+               args->nfs_server.hostname = c;
+
+               c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
+               if (IS_ERR(c))
+                       return PTR_ERR(c);
+               args->nfs_server.export_path = c;
+               dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
+
+               c = strndup_user(data->client_addr.data, 16);
+               if (IS_ERR(c))
+                       return PTR_ERR(c);
+               args->client_address = c;
+
+               /*
+                * Translate to nfs_parsed_mount_data, which nfs4_fill_super
+                * can deal with.
+                */
+
+               args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
+               args->rsize     = data->rsize;
+               args->wsize     = data->wsize;
+               args->timeo     = data->timeo;
+               args->retrans   = data->retrans;
+               args->acregmin  = data->acregmin;
+               args->acregmax  = data->acregmax;
+               args->acdirmin  = data->acdirmin;
+               args->acdirmax  = data->acdirmax;
+               args->nfs_server.protocol = data->proto;
 
-       /* RFC3530: The default port for NFS is 2049 */
-       if (addr.sin_port == 0)
-               addr.sin_port = htons(NFS_PORT);
-
-       /* Grab the authentication type */
-       authflavour = RPC_AUTH_UNIX;
-       if (data->auth_flavourlen != 0) {
-               if (data->auth_flavourlen != 1) {
-                       dprintk("%s: Invalid number of RPC auth flavours %d.\n",
-                                       __FUNCTION__, data->auth_flavourlen);
-                       error = -EINVAL;
-                       goto out;
+               break;
+       default: {
+               unsigned int len;
+
+               if (nfs_parse_mount_options((char *)options, args) == 0)
+                       return -EINVAL;
+
+               if (!nfs_verify_server_address((struct sockaddr *)
+                                               &args->nfs_server.address))
+                       return -EINVAL;
+
+               switch (args->auth_flavor_len) {
+               case 0:
+                       args->auth_flavors[0] = RPC_AUTH_UNIX;
+                       break;
+               case 1:
+                       break;
+               default:
+                       goto out_inval_auth;
                }
 
-               if (copy_from_user(&authflavour, data->auth_flavours,
-                                  sizeof(authflavour))) {
-                       error = -EFAULT;
-                       goto out;
+               /*
+                * Split "dev_name" into "hostname:mntpath".
+                */
+               c = strchr(dev_name, ':');
+               if (c == NULL)
+                       return -EINVAL;
+               /* while calculating len, pretend ':' is '\0' */
+               len = c - dev_name;
+               if (len > NFS4_MAXNAMLEN)
+                       return -ENAMETOOLONG;
+               /* N.B. caller will free nfs_server.hostname in all cases */
+               args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
+               if (!args->nfs_server.hostname)
+                       goto out_nomem;
+
+               c++;                    /* step over the ':' */
+               len = strlen(c);
+               if (len > NFS4_MAXPATHLEN)
+                       return -ENAMETOOLONG;
+               args->nfs_server.export_path = kstrndup(c, len, GFP_KERNEL);
+               if (!args->nfs_server.export_path)
+                       goto out_nomem;
+
+               dprintk("NFS: MNTPATH: '%s'\n", args->nfs_server.export_path);
+
+               if (args->client_address == NULL)
+                       goto out_no_client_address;
+
+               break;
                }
        }
 
-       p = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
-       if (IS_ERR(p))
-               goto out_err;
-       hostname = p;
+       return 0;
 
-       p = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
-       if (IS_ERR(p))
-               goto out_err;
-       mntpath = p;
+out_no_data:
+       dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
+       return -EINVAL;
 
-       dprintk("MNTPATH: %s\n", mntpath);
+out_inval_auth:
+       dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
+                data->auth_flavourlen);
+       return -EINVAL;
 
-       p = strndup_user(data->client_addr.data, 16);
-       if (IS_ERR(p))
-               goto out_err;
-       ip_addr = p;
+out_nomem:
+       dfprintk(MOUNT, "NFS4: not enough memory to handle mount options\n");
+       return -ENOMEM;
+
+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
+ */
+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;
+       struct super_block *s;
+       struct nfs_server *server;
+       struct nfs_fh *mntfh;
+       struct dentry *mntroot;
+       int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+       struct nfs_sb_mountdata sb_mntdata = {
+               .mntflags = flags,
+       };
+       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, hostname, &addr, mntpath, ip_addr,
-                                   authflavour, &mntfh);
+       server = nfs4_create_server(data, mntfh);
        if (IS_ERR(server)) {
                error = PTR_ERR(server);
                goto out;
        }
+       sb_mntdata.server = server;
+
+       if (server->flags & NFS4_MOUNT_UNSHARED)
+               compare_super = NULL;
 
        /* Get a superblock - note that we may end up sharing one that already exists */
-       s = sget(fs_type, nfs_compare_super, nfs_set_super, server);
+       s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto out_free;
@@ -907,39 +2082,48 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
        if (s->s_fs_info != server) {
                nfs_free_server(server);
                server = NULL;
+       } else {
+               error = nfs_bdi_register(server);
+               if (error)
+                       goto error_splat_super;
        }
 
        if (!s->s_root) {
                /* initial superblock/root creation */
-               s->s_flags = flags;
                nfs4_fill_super(s);
        }
 
-       mntroot = nfs4_get_root(s, &mntfh);
+       mntroot = nfs4_get_root(s, mntfh);
        if (IS_ERR(mntroot)) {
                error = PTR_ERR(mntroot);
                goto error_splat_super;
        }
 
+       error = security_sb_set_mnt_opts(s, &data->lsm_opts);
+       if (error)
+               goto error_splat_root;
+
        s->s_flags |= MS_ACTIVE;
        mnt->mnt_sb = s;
        mnt->mnt_root = mntroot;
        error = 0;
 
 out:
-       kfree(ip_addr);
-       kfree(mntpath);
-       kfree(hostname);
+       kfree(data->client_address);
+       kfree(data->nfs_server.export_path);
+       kfree(data->nfs_server.hostname);
+       security_free_mnt_opts(&data->lsm_opts);
+out_free_fh:
+       kfree(mntfh);
+       kfree(data);
        return error;
 
-out_err:
-       error = PTR_ERR(p);
-       goto out;
-
 out_free:
        nfs_free_server(server);
        goto out;
 
+error_splat_root:
+       dput(mntroot);
 error_splat_super:
        up_write(&s->s_umount);
        deactivate_super(s);
@@ -968,6 +2152,10 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
        struct super_block *s;
        struct nfs_server *server;
        struct dentry *mntroot;
+       int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+       struct nfs_sb_mountdata sb_mntdata = {
+               .mntflags = flags,
+       };
        int error;
 
        dprintk("--> nfs4_xdev_get_sb()\n");
@@ -978,9 +2166,13 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
                error = PTR_ERR(server);
                goto out_err_noserver;
        }
+       sb_mntdata.server = server;
+
+       if (server->flags & NFS4_MOUNT_UNSHARED)
+               compare_super = NULL;
 
        /* Get a superblock - note that we may end up sharing one that already exists */
-       s = sget(&nfs_fs_type, nfs_compare_super, nfs_set_super, server);
+       s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto out_err_nosb;
@@ -989,11 +2181,14 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
        if (s->s_fs_info != server) {
                nfs_free_server(server);
                server = NULL;
+       } else {
+               error = nfs_bdi_register(server);
+               if (error)
+                       goto error_splat_super;
        }
 
        if (!s->s_root) {
                /* initial superblock/root creation */
-               s->s_flags = flags;
                nfs4_clone_super(s, data->sb);
        }
 
@@ -1002,11 +2197,18 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
                error = PTR_ERR(mntroot);
                goto error_splat_super;
        }
+       if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+               dput(mntroot);
+               error = -ESTALE;
+               goto error_splat_super;
+       }
 
        s->s_flags |= MS_ACTIVE;
        mnt->mnt_sb = s;
        mnt->mnt_root = mntroot;
 
+       security_sb_clone_mnt_opts(data->sb, s);
+
        dprintk("<-- nfs4_xdev_get_sb() = 0\n");
        return 0;
 
@@ -1035,6 +2237,10 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
        struct nfs_server *server;
        struct dentry *mntroot;
        struct nfs_fh mntfh;
+       int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+       struct nfs_sb_mountdata sb_mntdata = {
+               .mntflags = flags,
+       };
        int error;
 
        dprintk("--> nfs4_referral_get_sb()\n");
@@ -1045,9 +2251,13 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
                error = PTR_ERR(server);
                goto out_err_noserver;
        }
+       sb_mntdata.server = server;
+
+       if (server->flags & NFS4_MOUNT_UNSHARED)
+               compare_super = NULL;
 
        /* Get a superblock - note that we may end up sharing one that already exists */
-       s = sget(&nfs_fs_type, nfs_compare_super, nfs_set_super, server);
+       s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto out_err_nosb;
@@ -1056,11 +2266,14 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
        if (s->s_fs_info != server) {
                nfs_free_server(server);
                server = NULL;
+       } else {
+               error = nfs_bdi_register(server);
+               if (error)
+                       goto error_splat_super;
        }
 
        if (!s->s_root) {
                /* initial superblock/root creation */
-               s->s_flags = flags;
                nfs4_fill_super(s);
        }
 
@@ -1069,11 +2282,18 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
                error = PTR_ERR(mntroot);
                goto error_splat_super;
        }
+       if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+               dput(mntroot);
+               error = -ESTALE;
+               goto error_splat_super;
+       }
 
        s->s_flags |= MS_ACTIVE;
        mnt->mnt_sb = s;
        mnt->mnt_root = mntroot;
 
+       security_sb_clone_mnt_opts(data->sb, s);
+
        dprintk("<-- nfs4_referral_get_sb() = 0\n");
        return 0;