git.oblomov.eu Git - linux-2.6/blob - fs/nfs/super.c

   1 /*
   2  *  linux/fs/nfs/super.c
   3  *
   4  *  Copyright (C) 1992  Rick Sladkey
   5  *
   6  *  nfs superblock handling functions
   7  *
   8  *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
   9  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
  10  *
  11  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
  12  *  J.S.Peatfield@damtp.cam.ac.uk
  13  *
  14  *  Split from inode.c by David Howells <dhowells@redhat.com>
  15  *
  16  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
  17  *   particular server are held in the same superblock
  18  * - NFS superblocks can have several effective roots to the dentry tree
  19  * - directory type roots are spliced into the tree when a path from one root reaches the root
  20  *   of another (see nfs_lookup())
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25
  26 #include <linux/time.h>
  27 #include <linux/kernel.h>
  28 #include <linux/mm.h>
  29 #include <linux/string.h>
  30 #include <linux/stat.h>
  31 #include <linux/errno.h>
  32 #include <linux/unistd.h>
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/stats.h>
  35 #include <linux/sunrpc/metrics.h>
  36 #include <linux/sunrpc/xprtsock.h>
  37 #include <linux/sunrpc/xprtrdma.h>
  38 #include <linux/nfs_fs.h>
  39 #include <linux/nfs_mount.h>
  40 #include <linux/nfs4_mount.h>
  41 #include <linux/lockd/bind.h>
  42 #include <linux/smp_lock.h>
  43 #include <linux/seq_file.h>
  44 #include <linux/mount.h>
  45 #include <linux/nfs_idmap.h>
  46 #include <linux/vfs.h>
  47 #include <linux/inet.h>
  48 #include <linux/in6.h>
  49 #include <net/ipv6.h>
  50 #include <linux/netdevice.h>
  51 #include <linux/nfs_xdr.h>
  52 #include <linux/magic.h>
  53 #include <linux/parser.h>
  54
  55 #include <asm/system.h>
  56 #include <asm/uaccess.h>
  57
  58 #include "nfs4_fs.h"
  59 #include "callback.h"
  60 #include "delegation.h"
  61 #include "iostat.h"
  62 #include "internal.h"
  63
  64 #define NFSDBG_FACILITY         NFSDBG_VFS
  65
  66 enum {
  67         /* Mount options that take no arguments */
  68         Opt_soft, Opt_hard,
  69         Opt_posix, Opt_noposix,
  70         Opt_cto, Opt_nocto,
  71         Opt_ac, Opt_noac,
  72         Opt_lock, Opt_nolock,
  73         Opt_v2, Opt_v3,
  74         Opt_udp, Opt_tcp, Opt_rdma,
  75         Opt_acl, Opt_noacl,
  76         Opt_rdirplus, Opt_nordirplus,
  77         Opt_sharecache, Opt_nosharecache,
  78
  79         /* Mount options that take integer arguments */
  80         Opt_port,
  81         Opt_rsize, Opt_wsize, Opt_bsize,
  82         Opt_timeo, Opt_retrans,
  83         Opt_acregmin, Opt_acregmax,
  84         Opt_acdirmin, Opt_acdirmax,
  85         Opt_actimeo,
  86         Opt_namelen,
  87         Opt_mountport,
  88         Opt_mountvers,
  89         Opt_nfsvers,
  90
  91         /* Mount options that take string arguments */
  92         Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
  93         Opt_addr, Opt_mountaddr, Opt_clientaddr,
  94         Opt_lookupcache,
  95
  96         /* Special mount options */
  97         Opt_userspace, Opt_deprecated, Opt_sloppy,
  98
  99         Opt_err
 100 };
 101
 102 static const match_table_t nfs_mount_option_tokens = {
 103         { Opt_userspace, "bg" },
 104         { Opt_userspace, "fg" },
 105         { Opt_userspace, "retry=%s" },
 106
 107         { Opt_sloppy, "sloppy" },
 108
 109         { Opt_soft, "soft" },
 110         { Opt_hard, "hard" },
 111         { Opt_deprecated, "intr" },
 112         { Opt_deprecated, "nointr" },
 113         { Opt_posix, "posix" },
 114         { Opt_noposix, "noposix" },
 115         { Opt_cto, "cto" },
 116         { Opt_nocto, "nocto" },
 117         { Opt_ac, "ac" },
 118         { Opt_noac, "noac" },
 119         { Opt_lock, "lock" },
 120         { Opt_nolock, "nolock" },
 121         { Opt_v2, "v2" },
 122         { Opt_v3, "v3" },
 123         { Opt_udp, "udp" },
 124         { Opt_tcp, "tcp" },
 125         { Opt_rdma, "rdma" },
 126         { Opt_acl, "acl" },
 127         { Opt_noacl, "noacl" },
 128         { Opt_rdirplus, "rdirplus" },
 129         { Opt_nordirplus, "nordirplus" },
 130         { Opt_sharecache, "sharecache" },
 131         { Opt_nosharecache, "nosharecache" },
 132
 133         { Opt_port, "port=%u" },
 134         { Opt_rsize, "rsize=%u" },
 135         { Opt_wsize, "wsize=%u" },
 136         { Opt_bsize, "bsize=%u" },
 137         { Opt_timeo, "timeo=%u" },
 138         { Opt_retrans, "retrans=%u" },
 139         { Opt_acregmin, "acregmin=%u" },
 140         { Opt_acregmax, "acregmax=%u" },
 141         { Opt_acdirmin, "acdirmin=%u" },
 142         { Opt_acdirmax, "acdirmax=%u" },
 143         { Opt_actimeo, "actimeo=%u" },
 144         { Opt_namelen, "namlen=%u" },
 145         { Opt_mountport, "mountport=%u" },
 146         { Opt_mountvers, "mountvers=%u" },
 147         { Opt_nfsvers, "nfsvers=%u" },
 148         { Opt_nfsvers, "vers=%u" },
 149
 150         { Opt_sec, "sec=%s" },
 151         { Opt_proto, "proto=%s" },
 152         { Opt_mountproto, "mountproto=%s" },
 153         { Opt_addr, "addr=%s" },
 154         { Opt_clientaddr, "clientaddr=%s" },
 155         { Opt_mounthost, "mounthost=%s" },
 156         { Opt_mountaddr, "mountaddr=%s" },
 157
 158         { Opt_lookupcache, "lookupcache=%s" },
 159
 160         { Opt_err, NULL }
 161 };
 162
 163 enum {
 164         Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
 165
 166         Opt_xprt_err
 167 };
 168
 169 static const match_table_t nfs_xprt_protocol_tokens = {
 170         { Opt_xprt_udp, "udp" },
 171         { Opt_xprt_tcp, "tcp" },
 172         { Opt_xprt_rdma, "rdma" },
 173
 174         { Opt_xprt_err, NULL }
 175 };
 176
 177 enum {
 178         Opt_sec_none, Opt_sec_sys,
 179         Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
 180         Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
 181         Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
 182
 183         Opt_sec_err
 184 };
 185
 186 static const match_table_t nfs_secflavor_tokens = {
 187         { Opt_sec_none, "none" },
 188         { Opt_sec_none, "null" },
 189         { Opt_sec_sys, "sys" },
 190
 191         { Opt_sec_krb5, "krb5" },
 192         { Opt_sec_krb5i, "krb5i" },
 193         { Opt_sec_krb5p, "krb5p" },
 194
 195         { Opt_sec_lkey, "lkey" },
 196         { Opt_sec_lkeyi, "lkeyi" },
 197         { Opt_sec_lkeyp, "lkeyp" },
 198
 199         { Opt_sec_spkm, "spkm3" },
 200         { Opt_sec_spkmi, "spkm3i" },
 201         { Opt_sec_spkmp, "spkm3p" },
 202
 203         { Opt_sec_err, NULL }
 204 };
 205
 206 enum {
 207         Opt_lookupcache_all, Opt_lookupcache_positive,
 208         Opt_lookupcache_none,
 209
 210         Opt_lookupcache_err
 211 };
 212
 213 static match_table_t nfs_lookupcache_tokens = {
 214         { Opt_lookupcache_all, "all" },
 215         { Opt_lookupcache_positive, "pos" },
 216         { Opt_lookupcache_positive, "positive" },
 217         { Opt_lookupcache_none, "none" },
 218
 219         { Opt_lookupcache_err, NULL }
 220 };
 221
 222
 223 static void nfs_umount_begin(struct super_block *);
 224 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 225 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 226 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
 227 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
 228 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
 229                 int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 230 static void nfs_kill_super(struct super_block *);
 231 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 232
 233 static struct file_system_type nfs_fs_type = {
 234         .owner          = THIS_MODULE,
 235         .name           = "nfs",
 236         .get_sb         = nfs_get_sb,
 237         .kill_sb        = nfs_kill_super,
 238         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 239 };
 240
 241 struct file_system_type nfs_xdev_fs_type = {
 242         .owner          = THIS_MODULE,
 243         .name           = "nfs",
 244         .get_sb         = nfs_xdev_get_sb,
 245         .kill_sb        = nfs_kill_super,
 246         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 247 };
 248
 249 static const struct super_operations nfs_sops = {
 250         .alloc_inode    = nfs_alloc_inode,
 251         .destroy_inode  = nfs_destroy_inode,
 252         .write_inode    = nfs_write_inode,
 253         .statfs         = nfs_statfs,
 254         .clear_inode    = nfs_clear_inode,
 255         .umount_begin   = nfs_umount_begin,
 256         .show_options   = nfs_show_options,
 257         .show_stats     = nfs_show_stats,
 258         .remount_fs     = nfs_remount,
 259 };
 260
 261 #ifdef CONFIG_NFS_V4
 262 static int nfs4_get_sb(struct file_system_type *fs_type,
 263         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 264 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
 265         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 266 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 267         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 268 static void nfs4_kill_super(struct super_block *sb);
 269
 270 static struct file_system_type nfs4_fs_type = {
 271         .owner          = THIS_MODULE,
 272         .name           = "nfs4",
 273         .get_sb         = nfs4_get_sb,
 274         .kill_sb        = nfs4_kill_super,
 275         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 276 };
 277
 278 struct file_system_type nfs4_xdev_fs_type = {
 279         .owner          = THIS_MODULE,
 280         .name           = "nfs4",
 281         .get_sb         = nfs4_xdev_get_sb,
 282         .kill_sb        = nfs4_kill_super,
 283         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 284 };
 285
 286 struct file_system_type nfs4_referral_fs_type = {
 287         .owner          = THIS_MODULE,
 288         .name           = "nfs4",
 289         .get_sb         = nfs4_referral_get_sb,
 290         .kill_sb        = nfs4_kill_super,
 291         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 292 };
 293
 294 static const struct super_operations nfs4_sops = {
 295         .alloc_inode    = nfs_alloc_inode,
 296         .destroy_inode  = nfs_destroy_inode,
 297         .write_inode    = nfs_write_inode,
 298         .statfs         = nfs_statfs,
 299         .clear_inode    = nfs4_clear_inode,
 300         .umount_begin   = nfs_umount_begin,
 301         .show_options   = nfs_show_options,
 302         .show_stats     = nfs_show_stats,
 303         .remount_fs     = nfs_remount,
 304 };
 305 #endif
 306
 307 static struct shrinker acl_shrinker = {
 308         .shrink         = nfs_access_cache_shrinker,
 309         .seeks          = DEFAULT_SEEKS,
 310 };
 311
 312 /*
 313  * Register the NFS filesystems
 314  */
 315 int __init register_nfs_fs(void)
 316 {
 317         int ret;
 318
 319         ret = register_filesystem(&nfs_fs_type);
 320         if (ret < 0)
 321                 goto error_0;
 322
 323         ret = nfs_register_sysctl();
 324         if (ret < 0)
 325                 goto error_1;
 326 #ifdef CONFIG_NFS_V4
 327         ret = register_filesystem(&nfs4_fs_type);
 328         if (ret < 0)
 329                 goto error_2;
 330 #endif
 331         register_shrinker(&acl_shrinker);
 332         return 0;
 333
 334 #ifdef CONFIG_NFS_V4
 335 error_2:
 336         nfs_unregister_sysctl();
 337 #endif
 338 error_1:
 339         unregister_filesystem(&nfs_fs_type);
 340 error_0:
 341         return ret;
 342 }
 343
 344 /*
 345  * Unregister the NFS filesystems
 346  */
 347 void __exit unregister_nfs_fs(void)
 348 {
 349         unregister_shrinker(&acl_shrinker);
 350 #ifdef CONFIG_NFS_V4
 351         unregister_filesystem(&nfs4_fs_type);
 352 #endif
 353         nfs_unregister_sysctl();
 354         unregister_filesystem(&nfs_fs_type);
 355 }
 356
 357 void nfs_sb_active(struct super_block *sb)
 358 {
 359         struct nfs_server *server = NFS_SB(sb);
 360
 361         if (atomic_inc_return(&server->active) == 1)
 362                 atomic_inc(&sb->s_active);
 363 }
 364
 365 void nfs_sb_deactive(struct super_block *sb)
 366 {
 367         struct nfs_server *server = NFS_SB(sb);
 368
 369         if (atomic_dec_and_test(&server->active))
 370                 deactivate_super(sb);
 371 }
 372
 373 /*
 374  * Deliver file system statistics to userspace
 375  */
 376 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 377 {
 378         struct nfs_server *server = NFS_SB(dentry->d_sb);
 379         unsigned char blockbits;
 380         unsigned long blockres;
 381         struct nfs_fh *fh = NFS_FH(dentry->d_inode);
 382         struct nfs_fattr fattr;
 383         struct nfs_fsstat res = {
 384                         .fattr = &fattr,
 385         };
 386         int error;
 387
 388         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 389         if (error < 0)
 390                 goto out_err;
 391         buf->f_type = NFS_SUPER_MAGIC;
 392
 393         /*
 394          * Current versions of glibc do not correctly handle the
 395          * case where f_frsize != f_bsize.  Eventually we want to
 396          * report the value of wtmult in this field.
 397          */
 398         buf->f_frsize = dentry->d_sb->s_blocksize;
 399
 400         /*
 401          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 402          * are reported in units of f_frsize.  Linux hasn't had
 403          * an f_frsize field in its statfs struct until recently,
 404          * thus historically Linux's sys_statfs reports these
 405          * fields in units of f_bsize.
 406          */
 407         buf->f_bsize = dentry->d_sb->s_blocksize;
 408         blockbits = dentry->d_sb->s_blocksize_bits;
 409         blockres = (1 << blockbits) - 1;
 410         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 411         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 412         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 413
 414         buf->f_files = res.tfiles;
 415         buf->f_ffree = res.afiles;
 416
 417         buf->f_namelen = server->namelen;
 418
 419         return 0;
 420
 421  out_err:
 422         dprintk("%s: statfs error = %d\n", __func__, -error);
 423         return error;
 424 }
 425
 426 /*
 427  * Map the security flavour number to a name
 428  */
 429 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 430 {
 431         static const struct {
 432                 rpc_authflavor_t flavour;
 433                 const char *str;
 434         } sec_flavours[] = {
 435                 { RPC_AUTH_NULL, "null" },
 436                 { RPC_AUTH_UNIX, "sys" },
 437                 { RPC_AUTH_GSS_KRB5, "krb5" },
 438                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 439                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 440                 { RPC_AUTH_GSS_LKEY, "lkey" },
 441                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 442                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 443                 { RPC_AUTH_GSS_SPKM, "spkm" },
 444                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 445                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 446                 { UINT_MAX, "unknown" }
 447         };
 448         int i;
 449
 450         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 451                 if (sec_flavours[i].flavour == flavour)
 452                         break;
 453         }
 454         return sec_flavours[i].str;
 455 }
 456
 457 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
 458                                     int showdefaults)
 459 {
 460         struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
 461
 462         switch (sap->sa_family) {
 463         case AF_INET: {
 464                 struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 465                 seq_printf(m, ",mountaddr=" NIPQUAD_FMT,
 466                                 NIPQUAD(sin->sin_addr.s_addr));
 467                 break;
 468         }
 469         case AF_INET6: {
 470                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 471                 seq_printf(m, ",mountaddr=%pI6", &sin6->sin6_addr);
 472                 break;
 473         }
 474         default:
 475                 if (showdefaults)
 476                         seq_printf(m, ",mountaddr=unspecified");
 477         }
 478
 479         if (nfss->mountd_version || showdefaults)
 480                 seq_printf(m, ",mountvers=%u", nfss->mountd_version);
 481         if (nfss->mountd_port || showdefaults)
 482                 seq_printf(m, ",mountport=%u", nfss->mountd_port);
 483
 484         switch (nfss->mountd_protocol) {
 485         case IPPROTO_UDP:
 486                 seq_printf(m, ",mountproto=udp");
 487                 break;
 488         case IPPROTO_TCP:
 489                 seq_printf(m, ",mountproto=tcp");
 490                 break;
 491         default:
 492                 if (showdefaults)
 493                         seq_printf(m, ",mountproto=auto");
 494         }
 495 }
 496
 497 /*
 498  * Describe the mount options in force on this server representation
 499  */
 500 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
 501                                    int showdefaults)
 502 {
 503         static const struct proc_nfs_info {
 504                 int flag;
 505                 const char *str;
 506                 const char *nostr;
 507         } nfs_info[] = {
 508                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 509                 { NFS_MOUNT_INTR, ",intr", ",nointr" },
 510                 { NFS_MOUNT_POSIX, ",posix", "" },
 511                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 512                 { NFS_MOUNT_NOAC, ",noac", "" },
 513                 { NFS_MOUNT_NONLM, ",nolock", "" },
 514                 { NFS_MOUNT_NOACL, ",noacl", "" },
 515                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 516                 { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
 517                 { 0, NULL, NULL }
 518         };
 519         const struct proc_nfs_info *nfs_infop;
 520         struct nfs_client *clp = nfss->nfs_client;
 521         u32 version = clp->rpc_ops->version;
 522
 523         seq_printf(m, ",vers=%u", version);
 524         seq_printf(m, ",rsize=%u", nfss->rsize);
 525         seq_printf(m, ",wsize=%u", nfss->wsize);
 526         if (nfss->bsize != 0)
 527                 seq_printf(m, ",bsize=%u", nfss->bsize);
 528         seq_printf(m, ",namlen=%u", nfss->namelen);
 529         if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
 530                 seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
 531         if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
 532                 seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
 533         if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
 534                 seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
 535         if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
 536                 seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
 537         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 538                 if (nfss->flags & nfs_infop->flag)
 539                         seq_puts(m, nfs_infop->str);
 540                 else
 541                         seq_puts(m, nfs_infop->nostr);
 542         }
 543         seq_printf(m, ",proto=%s",
 544                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
 545         if (version == 4) {
 546                 if (nfss->port != NFS_PORT)
 547                         seq_printf(m, ",port=%u", nfss->port);
 548         } else
 549                 if (nfss->port)
 550                         seq_printf(m, ",port=%u", nfss->port);
 551
 552         seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
 553         seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
 554         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 555
 556         if (version != 4)
 557                 nfs_show_mountd_options(m, nfss, showdefaults);
 558
 559 #ifdef CONFIG_NFS_V4
 560         if (clp->rpc_ops->version == 4)
 561                 seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
 562 #endif
 563 }
 564
 565 /*
 566  * Describe the mount options on this VFS mountpoint
 567  */
 568 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 569 {
 570         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 571
 572         nfs_show_mount_options(m, nfss, 0);
 573
 574         seq_printf(m, ",addr=%s",
 575                         rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
 576                                                         RPC_DISPLAY_ADDR));
 577
 578         return 0;
 579 }
 580
 581 /*
 582  * Present statistical information for this VFS mountpoint
 583  */
 584 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 585 {
 586         int i, cpu;
 587         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 588         struct rpc_auth *auth = nfss->client->cl_auth;
 589         struct nfs_iostats totals = { };
 590
 591         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 592
 593         /*
 594          * Display all mount option settings
 595          */
 596         seq_printf(m, "\n\topts:\t");
 597         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 598         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 599         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 600         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 601         nfs_show_mount_options(m, nfss, 1);
 602
 603         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 604
 605         seq_printf(m, "\n\tcaps:\t");
 606         seq_printf(m, "caps=0x%x", nfss->caps);
 607         seq_printf(m, ",wtmult=%u", nfss->wtmult);
 608         seq_printf(m, ",dtsize=%u", nfss->dtsize);
 609         seq_printf(m, ",bsize=%u", nfss->bsize);
 610         seq_printf(m, ",namlen=%u", nfss->namelen);
 611
 612 #ifdef CONFIG_NFS_V4
 613         if (nfss->nfs_client->rpc_ops->version == 4) {
 614                 seq_printf(m, "\n\tnfsv4:\t");
 615                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 616                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 617                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 618         }
 619 #endif
 620
 621         /*
 622          * Display security flavor in effect for this mount
 623          */
 624         seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
 625         if (auth->au_flavor)
 626                 seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
 627
 628         /*
 629          * Display superblock I/O counters
 630          */
 631         for_each_possible_cpu(cpu) {
 632                 struct nfs_iostats *stats;
 633
 634                 preempt_disable();
 635                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 636
 637                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 638                         totals.events[i] += stats->events[i];
 639                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 640                         totals.bytes[i] += stats->bytes[i];
 641
 642                 preempt_enable();
 643         }
 644
 645         seq_printf(m, "\n\tevents:\t");
 646         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 647                 seq_printf(m, "%lu ", totals.events[i]);
 648         seq_printf(m, "\n\tbytes:\t");
 649         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 650                 seq_printf(m, "%Lu ", totals.bytes[i]);
 651         seq_printf(m, "\n");
 652
 653         rpc_print_iostats(m, nfss->client);
 654
 655         return 0;
 656 }
 657
 658 /*
 659  * Begin unmount by attempting to remove all automounted mountpoints we added
 660  * in response to xdev traversals and referrals
 661  */
 662 static void nfs_umount_begin(struct super_block *sb)
 663 {
 664         struct nfs_server *server = NFS_SB(sb);
 665         struct rpc_clnt *rpc;
 666
 667         /* -EIO all pending I/O */
 668         rpc = server->client_acl;
 669         if (!IS_ERR(rpc))
 670                 rpc_killall_tasks(rpc);
 671         rpc = server->client;
 672         if (!IS_ERR(rpc))
 673                 rpc_killall_tasks(rpc);
 674 }
 675
 676 /*
 677  * Sanity-check a server address provided by the mount command.
 678  *
 679  * Address family must be initialized, and address must not be
 680  * the ANY address for that family.
 681  */
 682 static int nfs_verify_server_address(struct sockaddr *addr)
 683 {
 684         switch (addr->sa_family) {
 685         case AF_INET: {
 686                 struct sockaddr_in *sa = (struct sockaddr_in *)addr;
 687                 return sa->sin_addr.s_addr != htonl(INADDR_ANY);
 688         }
 689         case AF_INET6: {
 690                 struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
 691                 return !ipv6_addr_any(sa);
 692         }
 693         }
 694
 695         return 0;
 696 }
 697
 698 static void nfs_parse_ipv4_address(char *string, size_t str_len,
 699                                    struct sockaddr *sap, size_t *addr_len)
 700 {
 701         struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 702         u8 *addr = (u8 *)&sin->sin_addr.s_addr;
 703
 704         if (str_len <= INET_ADDRSTRLEN) {
 705                 dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
 706                                 (int)str_len, string);
 707
 708                 sin->sin_family = AF_INET;
 709                 *addr_len = sizeof(*sin);
 710                 if (in4_pton(string, str_len, addr, '\0', NULL))
 711                         return;
 712         }
 713
 714         sap->sa_family = AF_UNSPEC;
 715         *addr_len = 0;
 716 }
 717
 718 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 719 static int nfs_parse_ipv6_scope_id(const char *string, const size_t str_len,
 720                                    const char *delim,
 721                                    struct sockaddr_in6 *sin6)
 722 {
 723         char *p;
 724         size_t len;
 725
 726         if ((string + str_len) == delim)
 727                 return 1;
 728
 729         if (*delim != IPV6_SCOPE_DELIMITER)
 730                 return 0;
 731
 732         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
 733                 return 0;
 734
 735         len = (string + str_len) - delim - 1;
 736         p = kstrndup(delim + 1, len, GFP_KERNEL);
 737         if (p) {
 738                 unsigned long scope_id = 0;
 739                 struct net_device *dev;
 740
 741                 dev = dev_get_by_name(&init_net, p);
 742                 if (dev != NULL) {
 743                         scope_id = dev->ifindex;
 744                         dev_put(dev);
 745                 } else {
 746                         if (strict_strtoul(p, 10, &scope_id) == 0) {
 747                                 kfree(p);
 748                                 return 0;
 749                         }
 750                 }
 751
 752                 kfree(p);
 753
 754                 sin6->sin6_scope_id = scope_id;
 755                 dfprintk(MOUNT, "NFS: IPv6 scope ID = %lu\n", scope_id);
 756                 return 1;
 757         }
 758
 759         return 0;
 760 }
 761
 762 static void nfs_parse_ipv6_address(char *string, size_t str_len,
 763                                    struct sockaddr *sap, size_t *addr_len)
 764 {
 765         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 766         u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
 767         const char *delim;
 768
 769         if (str_len <= INET6_ADDRSTRLEN) {
 770                 dfprintk(MOUNT, "NFS: parsing IPv6 address %*s\n",
 771                                 (int)str_len, string);
 772
 773                 sin6->sin6_family = AF_INET6;
 774                 *addr_len = sizeof(*sin6);
 775                 if (in6_pton(string, str_len, addr,
 776                                         IPV6_SCOPE_DELIMITER, &delim) != 0) {
 777                         if (nfs_parse_ipv6_scope_id(string, str_len,
 778                                                         delim, sin6) != 0)
 779                                 return;
 780                 }
 781         }
 782
 783         sap->sa_family = AF_UNSPEC;
 784         *addr_len = 0;
 785 }
 786 #else
 787 static void nfs_parse_ipv6_address(char *string, size_t str_len,
 788                                    struct sockaddr *sap, size_t *addr_len)
 789 {
 790         sap->sa_family = AF_UNSPEC;
 791         *addr_len = 0;
 792 }
 793 #endif
 794
 795 /*
 796  * Construct a sockaddr based on the contents of a string that contains
 797  * an IP address in presentation format.
 798  *
 799  * If there is a problem constructing the new sockaddr, set the address
 800  * family to AF_UNSPEC.
 801  */
 802 void nfs_parse_ip_address(char *string, size_t str_len,
 803                                  struct sockaddr *sap, size_t *addr_len)
 804 {
 805         unsigned int i, colons;
 806
 807         colons = 0;
 808         for (i = 0; i < str_len; i++)
 809                 if (string[i] == ':')
 810                         colons++;
 811
 812         if (colons >= 2)
 813                 nfs_parse_ipv6_address(string, str_len, sap, addr_len);
 814         else
 815                 nfs_parse_ipv4_address(string, str_len, sap, addr_len);
 816 }
 817
 818 /*
 819  * Sanity check the NFS transport protocol.
 820  *
 821  */
 822 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
 823 {
 824         switch (mnt->nfs_server.protocol) {
 825         case XPRT_TRANSPORT_UDP:
 826         case XPRT_TRANSPORT_TCP:
 827         case XPRT_TRANSPORT_RDMA:
 828                 break;
 829         default:
 830                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 831         }
 832 }
 833
 834 /*
 835  * For text based NFSv2/v3 mounts, the mount protocol transport default
 836  * settings should depend upon the specified NFS transport.
 837  */
 838 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
 839 {
 840         nfs_validate_transport_protocol(mnt);
 841
 842         if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
 843             mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
 844                         return;
 845         switch (mnt->nfs_server.protocol) {
 846         case XPRT_TRANSPORT_UDP:
 847                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 848                 break;
 849         case XPRT_TRANSPORT_TCP:
 850         case XPRT_TRANSPORT_RDMA:
 851                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 852         }
 853 }
 854
 855 /*
 856  * Parse the value of the 'sec=' option.
 857  *
 858  * The flavor_len setting is for v4 mounts.
 859  */
 860 static int nfs_parse_security_flavors(char *value,
 861                                       struct nfs_parsed_mount_data *mnt)
 862 {
 863         substring_t args[MAX_OPT_ARGS];
 864
 865         dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
 866
 867         switch (match_token(value, nfs_secflavor_tokens, args)) {
 868         case Opt_sec_none:
 869                 mnt->auth_flavor_len = 0;
 870                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 871                 break;
 872         case Opt_sec_sys:
 873                 mnt->auth_flavor_len = 0;
 874                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 875                 break;
 876         case Opt_sec_krb5:
 877                 mnt->auth_flavor_len = 1;
 878                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 879                 break;
 880         case Opt_sec_krb5i:
 881                 mnt->auth_flavor_len = 1;
 882                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 883                 break;
 884         case Opt_sec_krb5p:
 885                 mnt->auth_flavor_len = 1;
 886                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 887                 break;
 888         case Opt_sec_lkey:
 889                 mnt->auth_flavor_len = 1;
 890                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 891                 break;
 892         case Opt_sec_lkeyi:
 893                 mnt->auth_flavor_len = 1;
 894                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 895                 break;
 896         case Opt_sec_lkeyp:
 897                 mnt->auth_flavor_len = 1;
 898                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 899                 break;
 900         case Opt_sec_spkm:
 901                 mnt->auth_flavor_len = 1;
 902                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 903                 break;
 904         case Opt_sec_spkmi:
 905                 mnt->auth_flavor_len = 1;
 906                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 907                 break;
 908         case Opt_sec_spkmp:
 909                 mnt->auth_flavor_len = 1;
 910                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 911                 break;
 912         default:
 913                 return 0;
 914         }
 915
 916         return 1;
 917 }
 918
 919 static void nfs_parse_invalid_value(const char *option)
 920 {
 921         dfprintk(MOUNT, "NFS:   bad value specified for %s option\n", option);
 922 }
 923
 924 /*
 925  * Error-check and convert a string of mount options from user space into
 926  * a data structure.  The whole mount string is processed; bad options are
 927  * skipped as they are encountered.  If there were no errors, return 1;
 928  * otherwise return 0 (zero).
 929  */
 930 static int nfs_parse_mount_options(char *raw,
 931                                    struct nfs_parsed_mount_data *mnt)
 932 {
 933         char *p, *string, *secdata;
 934         int rc, sloppy = 0, errors = 0;
 935
 936         if (!raw) {
 937                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 938                 return 1;
 939         }
 940         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 941
 942         secdata = alloc_secdata();
 943         if (!secdata)
 944                 goto out_nomem;
 945
 946         rc = security_sb_copy_data(raw, secdata);
 947         if (rc)
 948                 goto out_security_failure;
 949
 950         rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
 951         if (rc)
 952                 goto out_security_failure;
 953
 954         free_secdata(secdata);
 955
 956         while ((p = strsep(&raw, ",")) != NULL) {
 957                 substring_t args[MAX_OPT_ARGS];
 958                 int option, token;
 959
 960                 if (!*p)
 961                         continue;
 962
 963                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
 964
 965                 token = match_token(p, nfs_mount_option_tokens, args);
 966                 switch (token) {
 967
 968                 /*
 969                  * boolean options:  foo/nofoo
 970                  */
 971                 case Opt_soft:
 972                         mnt->flags |= NFS_MOUNT_SOFT;
 973                         break;
 974                 case Opt_hard:
 975                         mnt->flags &= ~NFS_MOUNT_SOFT;
 976                         break;
 977                 case Opt_posix:
 978                         mnt->flags |= NFS_MOUNT_POSIX;
 979                         break;
 980                 case Opt_noposix:
 981                         mnt->flags &= ~NFS_MOUNT_POSIX;
 982                         break;
 983                 case Opt_cto:
 984                         mnt->flags &= ~NFS_MOUNT_NOCTO;
 985                         break;
 986                 case Opt_nocto:
 987                         mnt->flags |= NFS_MOUNT_NOCTO;
 988                         break;
 989                 case Opt_ac:
 990                         mnt->flags &= ~NFS_MOUNT_NOAC;
 991                         break;
 992                 case Opt_noac:
 993                         mnt->flags |= NFS_MOUNT_NOAC;
 994                         break;
 995                 case Opt_lock:
 996                         mnt->flags &= ~NFS_MOUNT_NONLM;
 997                         break;
 998                 case Opt_nolock:
 999                         mnt->flags |= NFS_MOUNT_NONLM;
1000                         break;
1001                 case Opt_v2:
1002                         mnt->flags &= ~NFS_MOUNT_VER3;
1003                         break;
1004                 case Opt_v3:
1005                         mnt->flags |= NFS_MOUNT_VER3;
1006                         break;
1007                 case Opt_udp:
1008                         mnt->flags &= ~NFS_MOUNT_TCP;
1009                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1010                         break;
1011                 case Opt_tcp:
1012                         mnt->flags |= NFS_MOUNT_TCP;
1013                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1014                         break;
1015                 case Opt_rdma:
1016                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1017                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1018                         break;
1019                 case Opt_acl:
1020                         mnt->flags &= ~NFS_MOUNT_NOACL;
1021                         break;
1022                 case Opt_noacl:
1023                         mnt->flags |= NFS_MOUNT_NOACL;
1024                         break;
1025                 case Opt_rdirplus:
1026                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1027                         break;
1028                 case Opt_nordirplus:
1029                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1030                         break;
1031                 case Opt_sharecache:
1032                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
1033                         break;
1034                 case Opt_nosharecache:
1035                         mnt->flags |= NFS_MOUNT_UNSHARED;
1036                         break;
1037
1038                 /*
1039                  * options that take numeric values
1040                  */
1041                 case Opt_port:
1042                         if (match_int(args, &option) ||
1043                             option < 0 || option > USHORT_MAX) {
1044                                 errors++;
1045                                 nfs_parse_invalid_value("port");
1046                         } else
1047                                 mnt->nfs_server.port = option;
1048                         break;
1049                 case Opt_rsize:
1050                         if (match_int(args, &option) || option < 0) {
1051                                 errors++;
1052                                 nfs_parse_invalid_value("rsize");
1053                         } else
1054                                 mnt->rsize = option;
1055                         break;
1056                 case Opt_wsize:
1057                         if (match_int(args, &option) || option < 0) {
1058                                 errors++;
1059                                 nfs_parse_invalid_value("wsize");
1060                         } else
1061                                 mnt->wsize = option;
1062                         break;
1063                 case Opt_bsize:
1064                         if (match_int(args, &option) || option < 0) {
1065                                 errors++;
1066                                 nfs_parse_invalid_value("bsize");
1067                         } else
1068                                 mnt->bsize = option;
1069                         break;
1070                 case Opt_timeo:
1071                         if (match_int(args, &option) || option <= 0) {
1072                                 errors++;
1073                                 nfs_parse_invalid_value("timeo");
1074                         } else
1075                                 mnt->timeo = option;
1076                         break;
1077                 case Opt_retrans:
1078                         if (match_int(args, &option) || option <= 0) {
1079                                 errors++;
1080                                 nfs_parse_invalid_value("retrans");
1081                         } else
1082                                 mnt->retrans = option;
1083                         break;
1084                 case Opt_acregmin:
1085                         if (match_int(args, &option) || option < 0) {
1086                                 errors++;
1087                                 nfs_parse_invalid_value("acregmin");
1088                         } else
1089                                 mnt->acregmin = option;
1090                         break;
1091                 case Opt_acregmax:
1092                         if (match_int(args, &option) || option < 0) {
1093                                 errors++;
1094                                 nfs_parse_invalid_value("acregmax");
1095                         } else
1096                                 mnt->acregmax = option;
1097                         break;
1098                 case Opt_acdirmin:
1099                         if (match_int(args, &option) || option < 0) {
1100                                 errors++;
1101                                 nfs_parse_invalid_value("acdirmin");
1102                         } else
1103                                 mnt->acdirmin = option;
1104                         break;
1105                 case Opt_acdirmax:
1106                         if (match_int(args, &option) || option < 0) {
1107                                 errors++;
1108                                 nfs_parse_invalid_value("acdirmax");
1109                         } else
1110                                 mnt->acdirmax = option;
1111                         break;
1112                 case Opt_actimeo:
1113                         if (match_int(args, &option) || option < 0) {
1114                                 errors++;
1115                                 nfs_parse_invalid_value("actimeo");
1116                         } else
1117                                 mnt->acregmin = mnt->acregmax =
1118                                 mnt->acdirmin = mnt->acdirmax = option;
1119                         break;
1120                 case Opt_namelen:
1121                         if (match_int(args, &option) || option < 0) {
1122                                 errors++;
1123                                 nfs_parse_invalid_value("namlen");
1124                         } else
1125                                 mnt->namlen = option;
1126                         break;
1127                 case Opt_mountport:
1128                         if (match_int(args, &option) ||
1129                             option < 0 || option > USHORT_MAX) {
1130                                 errors++;
1131                                 nfs_parse_invalid_value("mountport");
1132                         } else
1133                                 mnt->mount_server.port = option;
1134                         break;
1135                 case Opt_mountvers:
1136                         if (match_int(args, &option) ||
1137                             option < NFS_MNT_VERSION ||
1138                             option > NFS_MNT3_VERSION) {
1139                                 errors++;
1140                                 nfs_parse_invalid_value("mountvers");
1141                         } else
1142                                 mnt->mount_server.version = option;
1143                         break;
1144                 case Opt_nfsvers:
1145                         if (match_int(args, &option)) {
1146                                 errors++;
1147                                 nfs_parse_invalid_value("nfsvers");
1148                                 break;
1149                         }
1150                         switch (option) {
1151                         case NFS2_VERSION:
1152                                 mnt->flags &= ~NFS_MOUNT_VER3;
1153                                 break;
1154                         case NFS3_VERSION:
1155                                 mnt->flags |= NFS_MOUNT_VER3;
1156                                 break;
1157                         default:
1158                                 errors++;
1159                                 nfs_parse_invalid_value("nfsvers");
1160                         }
1161                         break;
1162
1163                 /*
1164                  * options that take text values
1165                  */
1166                 case Opt_sec:
1167                         string = match_strdup(args);
1168                         if (string == NULL)
1169                                 goto out_nomem;
1170                         rc = nfs_parse_security_flavors(string, mnt);
1171                         kfree(string);
1172                         if (!rc) {
1173                                 errors++;
1174                                 dfprintk(MOUNT, "NFS:   unrecognized "
1175                                                 "security flavor\n");
1176                         }
1177                         break;
1178                 case Opt_proto:
1179                         string = match_strdup(args);
1180                         if (string == NULL)
1181                                 goto out_nomem;
1182                         token = match_token(string,
1183                                             nfs_xprt_protocol_tokens, args);
1184                         kfree(string);
1185
1186                         switch (token) {
1187                         case Opt_xprt_udp:
1188                                 mnt->flags &= ~NFS_MOUNT_TCP;
1189                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1190                                 break;
1191                         case Opt_xprt_tcp:
1192                                 mnt->flags |= NFS_MOUNT_TCP;
1193                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1194                                 break;
1195                         case Opt_xprt_rdma:
1196                                 /* vector side protocols to TCP */
1197                                 mnt->flags |= NFS_MOUNT_TCP;
1198                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1199                                 break;
1200                         default:
1201                                 errors++;
1202                                 dfprintk(MOUNT, "NFS:   unrecognized "
1203                                                 "transport protocol\n");
1204                         }
1205                         break;
1206                 case Opt_mountproto:
1207                         string = match_strdup(args);
1208                         if (string == NULL)
1209                                 goto out_nomem;
1210                         token = match_token(string,
1211                                             nfs_xprt_protocol_tokens, args);
1212                         kfree(string);
1213
1214                         switch (token) {
1215                         case Opt_xprt_udp:
1216                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1217                                 break;
1218                         case Opt_xprt_tcp:
1219                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1220                                 break;
1221                         case Opt_xprt_rdma: /* not used for side protocols */
1222                         default:
1223                                 errors++;
1224                                 dfprintk(MOUNT, "NFS:   unrecognized "
1225                                                 "transport protocol\n");
1226                         }
1227                         break;
1228                 case Opt_addr:
1229                         string = match_strdup(args);
1230                         if (string == NULL)
1231                                 goto out_nomem;
1232                         nfs_parse_ip_address(string, strlen(string),
1233                                              (struct sockaddr *)
1234                                                 &mnt->nfs_server.address,
1235                                              &mnt->nfs_server.addrlen);
1236                         kfree(string);
1237                         break;
1238                 case Opt_clientaddr:
1239                         string = match_strdup(args);
1240                         if (string == NULL)
1241                                 goto out_nomem;
1242                         kfree(mnt->client_address);
1243                         mnt->client_address = string;
1244                         break;
1245                 case Opt_mounthost:
1246                         string = match_strdup(args);
1247                         if (string == NULL)
1248                                 goto out_nomem;
1249                         kfree(mnt->mount_server.hostname);
1250                         mnt->mount_server.hostname = string;
1251                         break;
1252                 case Opt_mountaddr:
1253                         string = match_strdup(args);
1254                         if (string == NULL)
1255                                 goto out_nomem;
1256                         nfs_parse_ip_address(string, strlen(string),
1257                                              (struct sockaddr *)
1258                                                 &mnt->mount_server.address,
1259                                              &mnt->mount_server.addrlen);
1260                         kfree(string);
1261                         break;
1262                 case Opt_lookupcache:
1263                         string = match_strdup(args);
1264                         if (string == NULL)
1265                                 goto out_nomem;
1266                         token = match_token(string,
1267                                         nfs_lookupcache_tokens, args);
1268                         kfree(string);
1269                         switch (token) {
1270                                 case Opt_lookupcache_all:
1271                                         mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1272                                         break;
1273                                 case Opt_lookupcache_positive:
1274                                         mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1275                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1276                                         break;
1277                                 case Opt_lookupcache_none:
1278                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1279                                         break;
1280                                 default:
1281                                         errors++;
1282                                         dfprintk(MOUNT, "NFS:   invalid "
1283                                                         "lookupcache argument\n");
1284                         };
1285                         break;
1286
1287                 /*
1288                  * Special options
1289                  */
1290                 case Opt_sloppy:
1291                         sloppy = 1;
1292                         dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1293                         break;
1294                 case Opt_userspace:
1295                 case Opt_deprecated:
1296                         dfprintk(MOUNT, "NFS:   ignoring mount option "
1297                                         "'%s'\n", p);
1298                         break;
1299
1300                 default:
1301                         errors++;
1302                         dfprintk(MOUNT, "NFS:   unrecognized mount option "
1303                                         "'%s'\n", p);
1304                 }
1305         }
1306
1307         if (errors > 0) {
1308                 dfprintk(MOUNT, "NFS: parsing encountered %d error%s\n",
1309                                 errors, (errors == 1 ? "" : "s"));
1310                 if (!sloppy)
1311                         return 0;
1312         }
1313         return 1;
1314
1315 out_nomem:
1316         printk(KERN_INFO "NFS: not enough memory to parse option\n");
1317         return 0;
1318 out_security_failure:
1319         free_secdata(secdata);
1320         printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1321         return 0;
1322 }
1323
1324 /*
1325  * Use the remote server's MOUNT service to request the NFS file handle
1326  * corresponding to the provided path.
1327  */
1328 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1329                          struct nfs_fh *root_fh)
1330 {
1331         struct sockaddr *sap = (struct sockaddr *)&args->mount_server.address;
1332         char *hostname;
1333         int status;
1334
1335         if (args->mount_server.version == 0) {
1336                 if (args->flags & NFS_MOUNT_VER3)
1337                         args->mount_server.version = NFS_MNT3_VERSION;
1338                 else
1339                         args->mount_server.version = NFS_MNT_VERSION;
1340         }
1341
1342         if (args->mount_server.hostname)
1343                 hostname = args->mount_server.hostname;
1344         else
1345                 hostname = args->nfs_server.hostname;
1346
1347         /*
1348          * Construct the mount server's address.
1349          */
1350         if (args->mount_server.address.ss_family == AF_UNSPEC) {
1351                 memcpy(sap, &args->nfs_server.address,
1352                        args->nfs_server.addrlen);
1353                 args->mount_server.addrlen = args->nfs_server.addrlen;
1354         }
1355
1356         /*
1357          * autobind will be used if mount_server.port == 0
1358          */
1359         nfs_set_port(sap, args->mount_server.port);
1360
1361         /*
1362          * Now ask the mount server to map our export path
1363          * to a file handle.
1364          */
1365         status = nfs_mount(sap,
1366                            args->mount_server.addrlen,
1367                            hostname,
1368                            args->nfs_server.export_path,
1369                            args->mount_server.version,
1370                            args->mount_server.protocol,
1371                            root_fh);
1372         if (status == 0)
1373                 return 0;
1374
1375         dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1376                         hostname, status);
1377         return status;
1378 }
1379
1380 static int nfs_parse_simple_hostname(const char *dev_name,
1381                                      char **hostname, size_t maxnamlen,
1382                                      char **export_path, size_t maxpathlen)
1383 {
1384         size_t len;
1385         char *colon, *comma;
1386
1387         colon = strchr(dev_name, ':');
1388         if (colon == NULL)
1389                 goto out_bad_devname;
1390
1391         len = colon - dev_name;
1392         if (len > maxnamlen)
1393                 goto out_hostname;
1394
1395         /* N.B. caller will free nfs_server.hostname in all cases */
1396         *hostname = kstrndup(dev_name, len, GFP_KERNEL);
1397         if (!*hostname)
1398                 goto out_nomem;
1399
1400         /* kill possible hostname list: not supported */
1401         comma = strchr(*hostname, ',');
1402         if (comma != NULL) {
1403                 if (comma == *hostname)
1404                         goto out_bad_devname;
1405                 *comma = '\0';
1406         }
1407
1408         colon++;
1409         len = strlen(colon);
1410         if (len > maxpathlen)
1411                 goto out_path;
1412         *export_path = kstrndup(colon, len, GFP_KERNEL);
1413         if (!*export_path)
1414                 goto out_nomem;
1415
1416         dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1417         return 0;
1418
1419 out_bad_devname:
1420         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1421         return -EINVAL;
1422
1423 out_nomem:
1424         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1425         return -ENOMEM;
1426
1427 out_hostname:
1428         dfprintk(MOUNT, "NFS: server hostname too long\n");
1429         return -ENAMETOOLONG;
1430
1431 out_path:
1432         dfprintk(MOUNT, "NFS: export pathname too long\n");
1433         return -ENAMETOOLONG;
1434 }
1435
1436 /*
1437  * Hostname has square brackets around it because it contains one or
1438  * more colons.  We look for the first closing square bracket, and a
1439  * colon must follow it.
1440  */
1441 static int nfs_parse_protected_hostname(const char *dev_name,
1442                                         char **hostname, size_t maxnamlen,
1443                                         char **export_path, size_t maxpathlen)
1444 {
1445         size_t len;
1446         char *start, *end;
1447
1448         start = (char *)(dev_name + 1);
1449
1450         end = strchr(start, ']');
1451         if (end == NULL)
1452                 goto out_bad_devname;
1453         if (*(end + 1) != ':')
1454                 goto out_bad_devname;
1455
1456         len = end - start;
1457         if (len > maxnamlen)
1458                 goto out_hostname;
1459
1460         /* N.B. caller will free nfs_server.hostname in all cases */
1461         *hostname = kstrndup(start, len, GFP_KERNEL);
1462         if (*hostname == NULL)
1463                 goto out_nomem;
1464
1465         end += 2;
1466         len = strlen(end);
1467         if (len > maxpathlen)
1468                 goto out_path;
1469         *export_path = kstrndup(end, len, GFP_KERNEL);
1470         if (!*export_path)
1471                 goto out_nomem;
1472
1473         return 0;
1474
1475 out_bad_devname:
1476         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1477         return -EINVAL;
1478
1479 out_nomem:
1480         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1481         return -ENOMEM;
1482
1483 out_hostname:
1484         dfprintk(MOUNT, "NFS: server hostname too long\n");
1485         return -ENAMETOOLONG;
1486
1487 out_path:
1488         dfprintk(MOUNT, "NFS: export pathname too long\n");
1489         return -ENAMETOOLONG;
1490 }
1491
1492 /*
1493  * Split "dev_name" into "hostname:export_path".
1494  *
1495  * The leftmost colon demarks the split between the server's hostname
1496  * and the export path.  If the hostname starts with a left square
1497  * bracket, then it may contain colons.
1498  *
1499  * Note: caller frees hostname and export path, even on error.
1500  */
1501 static int nfs_parse_devname(const char *dev_name,
1502                              char **hostname, size_t maxnamlen,
1503                              char **export_path, size_t maxpathlen)
1504 {
1505         if (*dev_name == '[')
1506                 return nfs_parse_protected_hostname(dev_name,
1507                                                     hostname, maxnamlen,
1508                                                     export_path, maxpathlen);
1509
1510         return nfs_parse_simple_hostname(dev_name,
1511                                          hostname, maxnamlen,
1512                                          export_path, maxpathlen);
1513 }
1514
1515 /*
1516  * Validate the NFS2/NFS3 mount data
1517  * - fills in the mount root filehandle
1518  *
1519  * For option strings, user space handles the following behaviors:
1520  *
1521  * + DNS: mapping server host name to IP address ("addr=" option)
1522  *
1523  * + failure mode: how to behave if a mount request can't be handled
1524  *   immediately ("fg/bg" option)
1525  *
1526  * + retry: how often to retry a mount request ("retry=" option)
1527  *
1528  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1529  *   mountproto=tcp after mountproto=udp, and so on
1530  */
1531 static int nfs_validate_mount_data(void *options,
1532                                    struct nfs_parsed_mount_data *args,
1533                                    struct nfs_fh *mntfh,
1534                                    const char *dev_name)
1535 {
1536         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1537
1538         if (data == NULL)
1539                 goto out_no_data;
1540
1541         args->flags             = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1542         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1543         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1544         args->acregmin          = NFS_DEF_ACREGMIN;
1545         args->acregmax          = NFS_DEF_ACREGMAX;
1546         args->acdirmin          = NFS_DEF_ACDIRMIN;
1547         args->acdirmax          = NFS_DEF_ACDIRMAX;
1548         args->mount_server.port = 0;    /* autobind unless user sets port */
1549         args->nfs_server.port   = 0;    /* autobind unless user sets port */
1550         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1551         args->auth_flavors[0]   = RPC_AUTH_UNIX;
1552
1553         switch (data->version) {
1554         case 1:
1555                 data->namlen = 0;
1556         case 2:
1557                 data->bsize = 0;
1558         case 3:
1559                 if (data->flags & NFS_MOUNT_VER3)
1560                         goto out_no_v3;
1561                 data->root.size = NFS2_FHSIZE;
1562                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1563         case 4:
1564                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1565                         goto out_no_sec;
1566         case 5:
1567                 memset(data->context, 0, sizeof(data->context));
1568         case 6:
1569                 if (data->flags & NFS_MOUNT_VER3) {
1570                         if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1571                                 goto out_invalid_fh;
1572                         mntfh->size = data->root.size;
1573                 } else
1574                         mntfh->size = NFS2_FHSIZE;
1575
1576
1577                 memcpy(mntfh->data, data->root.data, mntfh->size);
1578                 if (mntfh->size < sizeof(mntfh->data))
1579                         memset(mntfh->data + mntfh->size, 0,
1580                                sizeof(mntfh->data) - mntfh->size);
1581
1582                 /*
1583                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1584                  * can deal with.
1585                  */
1586                 args->flags             = data->flags & NFS_MOUNT_FLAGMASK;
1587                 args->rsize             = data->rsize;
1588                 args->wsize             = data->wsize;
1589                 args->timeo             = data->timeo;
1590                 args->retrans           = data->retrans;
1591                 args->acregmin          = data->acregmin;
1592                 args->acregmax          = data->acregmax;
1593                 args->acdirmin          = data->acdirmin;
1594                 args->acdirmax          = data->acdirmax;
1595
1596                 memcpy(&args->nfs_server.address, &data->addr,
1597                        sizeof(data->addr));
1598                 args->nfs_server.addrlen = sizeof(data->addr);
1599                 if (!nfs_verify_server_address((struct sockaddr *)
1600                                                 &args->nfs_server.address))
1601                         goto out_no_address;
1602
1603                 if (!(data->flags & NFS_MOUNT_TCP))
1604                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1605                 /* N.B. caller will free nfs_server.hostname in all cases */
1606                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1607                 args->namlen            = data->namlen;
1608                 args->bsize             = data->bsize;
1609
1610                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1611                         args->auth_flavors[0] = data->pseudoflavor;
1612                 if (!args->nfs_server.hostname)
1613                         goto out_nomem;
1614
1615                 /*
1616                  * The legacy version 6 binary mount data from userspace has a
1617                  * field used only to transport selinux information into the
1618                  * the kernel.  To continue to support that functionality we
1619                  * have a touch of selinux knowledge here in the NFS code. The
1620                  * userspace code converted context=blah to just blah so we are
1621                  * converting back to the full string selinux understands.
1622                  */
1623                 if (data->context[0]){
1624 #ifdef CONFIG_SECURITY_SELINUX
1625                         int rc;
1626                         char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1627                         if (!opts_str)
1628                                 return -ENOMEM;
1629                         strcpy(opts_str, "context=");
1630                         data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1631                         strcat(opts_str, &data->context[0]);
1632                         rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1633                         kfree(opts_str);
1634                         if (rc)
1635                                 return rc;
1636 #else
1637                         return -EINVAL;
1638 #endif
1639                 }
1640
1641                 break;
1642         default: {
1643                 int status;
1644
1645                 if (nfs_parse_mount_options((char *)options, args) == 0)
1646                         return -EINVAL;
1647
1648                 if (!nfs_verify_server_address((struct sockaddr *)
1649                                                 &args->nfs_server.address))
1650                         goto out_no_address;
1651
1652                 nfs_set_port((struct sockaddr *)&args->nfs_server.address,
1653                                 args->nfs_server.port);
1654
1655                 nfs_set_mount_transport_protocol(args);
1656
1657                 status = nfs_parse_devname(dev_name,
1658                                            &args->nfs_server.hostname,
1659                                            PAGE_SIZE,
1660                                            &args->nfs_server.export_path,
1661                                            NFS_MAXPATHLEN);
1662                 if (!status)
1663                         status = nfs_try_mount(args, mntfh);
1664
1665                 kfree(args->nfs_server.export_path);
1666                 args->nfs_server.export_path = NULL;
1667
1668                 if (status)
1669                         return status;
1670
1671                 break;
1672                 }
1673         }
1674
1675 #ifndef CONFIG_NFS_V3
1676         if (args->flags & NFS_MOUNT_VER3)
1677                 goto out_v3_not_compiled;
1678 #endif /* !CONFIG_NFS_V3 */
1679
1680         return 0;
1681
1682 out_no_data:
1683         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1684         return -EINVAL;
1685
1686 out_no_v3:
1687         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1688                  data->version);
1689         return -EINVAL;
1690
1691 out_no_sec:
1692         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1693         return -EINVAL;
1694
1695 #ifndef CONFIG_NFS_V3
1696 out_v3_not_compiled:
1697         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1698         return -EPROTONOSUPPORT;
1699 #endif /* !CONFIG_NFS_V3 */
1700
1701 out_nomem:
1702         dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1703         return -ENOMEM;
1704
1705 out_no_address:
1706         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1707         return -EINVAL;
1708
1709 out_invalid_fh:
1710         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1711         return -EINVAL;
1712 }
1713
1714 static int
1715 nfs_compare_remount_data(struct nfs_server *nfss,
1716                          struct nfs_parsed_mount_data *data)
1717 {
1718         if (data->flags != nfss->flags ||
1719             data->rsize != nfss->rsize ||
1720             data->wsize != nfss->wsize ||
1721             data->retrans != nfss->client->cl_timeout->to_retries ||
1722             data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
1723             data->acregmin != nfss->acregmin / HZ ||
1724             data->acregmax != nfss->acregmax / HZ ||
1725             data->acdirmin != nfss->acdirmin / HZ ||
1726             data->acdirmax != nfss->acdirmax / HZ ||
1727             data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
1728             data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
1729             memcmp(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1730                    data->nfs_server.addrlen) != 0)
1731                 return -EINVAL;
1732
1733         return 0;
1734 }
1735
1736 static int
1737 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
1738 {
1739         int error;
1740         struct nfs_server *nfss = sb->s_fs_info;
1741         struct nfs_parsed_mount_data *data;
1742         struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
1743         struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
1744         u32 nfsvers = nfss->nfs_client->rpc_ops->version;
1745
1746         /*
1747          * Userspace mount programs that send binary options generally send
1748          * them populated with default values. We have no way to know which
1749          * ones were explicitly specified. Fall back to legacy behavior and
1750          * just return success.
1751          */
1752         if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
1753             (nfsvers <= 3 && (!options || (options->version >= 1 &&
1754                                            options->version <= 6))))
1755                 return 0;
1756
1757         data = kzalloc(sizeof(*data), GFP_KERNEL);
1758         if (data == NULL)
1759                 return -ENOMEM;
1760
1761         /* fill out struct with values from existing mount */
1762         data->flags = nfss->flags;
1763         data->rsize = nfss->rsize;
1764         data->wsize = nfss->wsize;
1765         data->retrans = nfss->client->cl_timeout->to_retries;
1766         data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
1767         data->acregmin = nfss->acregmin / HZ;
1768         data->acregmax = nfss->acregmax / HZ;
1769         data->acdirmin = nfss->acdirmin / HZ;
1770         data->acdirmax = nfss->acdirmax / HZ;
1771         data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
1772         data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
1773         memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1774                 data->nfs_server.addrlen);
1775
1776         /* overwrite those values with any that were specified */
1777         error = nfs_parse_mount_options((char *)options, data);
1778         if (error < 0)
1779                 goto out;
1780
1781         /* compare new mount options with old ones */
1782         error = nfs_compare_remount_data(nfss, data);
1783 out:
1784         kfree(data);
1785         return error;
1786 }
1787
1788 /*
1789  * Initialise the common bits of the superblock
1790  */
1791 static inline void nfs_initialise_sb(struct super_block *sb)
1792 {
1793         struct nfs_server *server = NFS_SB(sb);
1794
1795         sb->s_magic = NFS_SUPER_MAGIC;
1796
1797         /* We probably want something more informative here */
1798         snprintf(sb->s_id, sizeof(sb->s_id),
1799                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1800
1801         if (sb->s_blocksize == 0)
1802                 sb->s_blocksize = nfs_block_bits(server->wsize,
1803                                                  &sb->s_blocksize_bits);
1804
1805         if (server->flags & NFS_MOUNT_NOAC)
1806                 sb->s_flags |= MS_SYNCHRONOUS;
1807
1808         nfs_super_set_maxbytes(sb, server->maxfilesize);
1809 }
1810
1811 /*
1812  * Finish setting up an NFS2/3 superblock
1813  */
1814 static void nfs_fill_super(struct super_block *sb,
1815                            struct nfs_parsed_mount_data *data)
1816 {
1817         struct nfs_server *server = NFS_SB(sb);
1818
1819         sb->s_blocksize_bits = 0;
1820         sb->s_blocksize = 0;
1821         if (data->bsize)
1822                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1823
1824         if (server->flags & NFS_MOUNT_VER3) {
1825                 /* The VFS shouldn't apply the umask to mode bits. We will do
1826                  * so ourselves when necessary.
1827                  */
1828                 sb->s_flags |= MS_POSIXACL;
1829                 sb->s_time_gran = 1;
1830         }
1831
1832         sb->s_op = &nfs_sops;
1833         nfs_initialise_sb(sb);
1834 }
1835
1836 /*
1837  * Finish setting up a cloned NFS2/3 superblock
1838  */
1839 static void nfs_clone_super(struct super_block *sb,
1840                             const struct super_block *old_sb)
1841 {
1842         struct nfs_server *server = NFS_SB(sb);
1843
1844         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1845         sb->s_blocksize = old_sb->s_blocksize;
1846         sb->s_maxbytes = old_sb->s_maxbytes;
1847
1848         if (server->flags & NFS_MOUNT_VER3) {
1849                 /* The VFS shouldn't apply the umask to mode bits. We will do
1850                  * so ourselves when necessary.
1851                  */
1852                 sb->s_flags |= MS_POSIXACL;
1853                 sb->s_time_gran = 1;
1854         }
1855
1856         sb->s_op = old_sb->s_op;
1857         nfs_initialise_sb(sb);
1858 }
1859
1860 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1861
1862 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1863 {
1864         const struct nfs_server *a = s->s_fs_info;
1865         const struct rpc_clnt *clnt_a = a->client;
1866         const struct rpc_clnt *clnt_b = b->client;
1867
1868         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1869                 goto Ebusy;
1870         if (a->nfs_client != b->nfs_client)
1871                 goto Ebusy;
1872         if (a->flags != b->flags)
1873                 goto Ebusy;
1874         if (a->wsize != b->wsize)
1875                 goto Ebusy;
1876         if (a->rsize != b->rsize)
1877                 goto Ebusy;
1878         if (a->acregmin != b->acregmin)
1879                 goto Ebusy;
1880         if (a->acregmax != b->acregmax)
1881                 goto Ebusy;
1882         if (a->acdirmin != b->acdirmin)
1883                 goto Ebusy;
1884         if (a->acdirmax != b->acdirmax)
1885                 goto Ebusy;
1886         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1887                 goto Ebusy;
1888         return 1;
1889 Ebusy:
1890         return 0;
1891 }
1892
1893 struct nfs_sb_mountdata {
1894         struct nfs_server *server;
1895         int mntflags;
1896 };
1897
1898 static int nfs_set_super(struct super_block *s, void *data)
1899 {
1900         struct nfs_sb_mountdata *sb_mntdata = data;
1901         struct nfs_server *server = sb_mntdata->server;
1902         int ret;
1903
1904         s->s_flags = sb_mntdata->mntflags;
1905         s->s_fs_info = server;
1906         ret = set_anon_super(s, server);
1907         if (ret == 0)
1908                 server->s_dev = s->s_dev;
1909         return ret;
1910 }
1911
1912 static int nfs_compare_super_address(struct nfs_server *server1,
1913                                      struct nfs_server *server2)
1914 {
1915         struct sockaddr *sap1, *sap2;
1916
1917         sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1918         sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1919
1920         if (sap1->sa_family != sap2->sa_family)
1921                 return 0;
1922
1923         switch (sap1->sa_family) {
1924         case AF_INET: {
1925                 struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1926                 struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1927                 if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1928                         return 0;
1929                 if (sin1->sin_port != sin2->sin_port)
1930                         return 0;
1931                 break;
1932         }
1933         case AF_INET6: {
1934                 struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1935                 struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1936                 if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1937                         return 0;
1938                 if (sin1->sin6_port != sin2->sin6_port)
1939                         return 0;
1940                 break;
1941         }
1942         default:
1943                 return 0;
1944         }
1945
1946         return 1;
1947 }
1948
1949 static int nfs_compare_super(struct super_block *sb, void *data)
1950 {
1951         struct nfs_sb_mountdata *sb_mntdata = data;
1952         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1953         int mntflags = sb_mntdata->mntflags;
1954
1955         if (!nfs_compare_super_address(old, server))
1956                 return 0;
1957         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1958         if (old->flags & NFS_MOUNT_UNSHARED)
1959                 return 0;
1960         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1961                 return 0;
1962         return nfs_compare_mount_options(sb, server, mntflags);
1963 }
1964
1965 static int nfs_bdi_register(struct nfs_server *server)
1966 {
1967         return bdi_register_dev(&server->backing_dev_info, server->s_dev);
1968 }
1969
1970 static int nfs_get_sb(struct file_system_type *fs_type,
1971         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1972 {
1973         struct nfs_server *server = NULL;
1974         struct super_block *s;
1975         struct nfs_parsed_mount_data *data;
1976         struct nfs_fh *mntfh;
1977         struct dentry *mntroot;
1978         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1979         struct nfs_sb_mountdata sb_mntdata = {
1980                 .mntflags = flags,
1981         };
1982         int error = -ENOMEM;
1983
1984         data = kzalloc(sizeof(*data), GFP_KERNEL);
1985         mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
1986         if (data == NULL || mntfh == NULL)
1987                 goto out_free_fh;
1988
1989         security_init_mnt_opts(&data->lsm_opts);
1990
1991         /* Validate the mount data */
1992         error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
1993         if (error < 0)
1994                 goto out;
1995
1996         /* Get a volume representation */
1997         server = nfs_create_server(data, mntfh);
1998         if (IS_ERR(server)) {
1999                 error = PTR_ERR(server);
2000                 goto out;
2001         }
2002         sb_mntdata.server = server;
2003
2004         if (server->flags & NFS_MOUNT_UNSHARED)
2005                 compare_super = NULL;
2006
2007         /* Get a superblock - note that we may end up sharing one that already exists */
2008         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2009         if (IS_ERR(s)) {
2010                 error = PTR_ERR(s);
2011                 goto out_err_nosb;
2012         }
2013
2014         if (s->s_fs_info != server) {
2015                 nfs_free_server(server);
2016                 server = NULL;
2017         } else {
2018                 error = nfs_bdi_register(server);
2019                 if (error)
2020                         goto error_splat_super;
2021         }
2022
2023         if (!s->s_root) {
2024                 /* initial superblock/root creation */
2025                 nfs_fill_super(s, data);
2026         }
2027
2028         mntroot = nfs_get_root(s, mntfh);
2029         if (IS_ERR(mntroot)) {
2030                 error = PTR_ERR(mntroot);
2031                 goto error_splat_super;
2032         }
2033
2034         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2035         if (error)
2036                 goto error_splat_root;
2037
2038         s->s_flags |= MS_ACTIVE;
2039         mnt->mnt_sb = s;
2040         mnt->mnt_root = mntroot;
2041         error = 0;
2042
2043 out:
2044         kfree(data->nfs_server.hostname);
2045         kfree(data->mount_server.hostname);
2046         security_free_mnt_opts(&data->lsm_opts);
2047 out_free_fh:
2048         kfree(mntfh);
2049         kfree(data);
2050         return error;
2051
2052 out_err_nosb:
2053         nfs_free_server(server);
2054         goto out;
2055
2056 error_splat_root:
2057         dput(mntroot);
2058 error_splat_super:
2059         up_write(&s->s_umount);
2060         deactivate_super(s);
2061         goto out;
2062 }
2063
2064 /*
2065  * Destroy an NFS2/3 superblock
2066  */
2067 static void nfs_kill_super(struct super_block *s)
2068 {
2069         struct nfs_server *server = NFS_SB(s);
2070
2071         bdi_unregister(&server->backing_dev_info);
2072         kill_anon_super(s);
2073         nfs_free_server(server);
2074 }
2075
2076 /*
2077  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2078  */
2079 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
2080                            const char *dev_name, void *raw_data,
2081                            struct vfsmount *mnt)
2082 {
2083         struct nfs_clone_mount *data = raw_data;
2084         struct super_block *s;
2085         struct nfs_server *server;
2086         struct dentry *mntroot;
2087         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2088         struct nfs_sb_mountdata sb_mntdata = {
2089                 .mntflags = flags,
2090         };
2091         int error;
2092
2093         dprintk("--> nfs_xdev_get_sb()\n");
2094
2095         /* create a new volume representation */
2096         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2097         if (IS_ERR(server)) {
2098                 error = PTR_ERR(server);
2099                 goto out_err_noserver;
2100         }
2101         sb_mntdata.server = server;
2102
2103         if (server->flags & NFS_MOUNT_UNSHARED)
2104                 compare_super = NULL;
2105
2106         /* Get a superblock - note that we may end up sharing one that already exists */
2107         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2108         if (IS_ERR(s)) {
2109                 error = PTR_ERR(s);
2110                 goto out_err_nosb;
2111         }
2112
2113         if (s->s_fs_info != server) {
2114                 nfs_free_server(server);
2115                 server = NULL;
2116         } else {
2117                 error = nfs_bdi_register(server);
2118                 if (error)
2119                         goto error_splat_super;
2120         }
2121
2122         if (!s->s_root) {
2123                 /* initial superblock/root creation */
2124                 nfs_clone_super(s, data->sb);
2125         }
2126
2127         mntroot = nfs_get_root(s, data->fh);
2128         if (IS_ERR(mntroot)) {
2129                 error = PTR_ERR(mntroot);
2130                 goto error_splat_super;
2131         }
2132         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2133                 dput(mntroot);
2134                 error = -ESTALE;
2135                 goto error_splat_super;
2136         }
2137
2138         s->s_flags |= MS_ACTIVE;
2139         mnt->mnt_sb = s;
2140         mnt->mnt_root = mntroot;
2141
2142         /* clone any lsm security options from the parent to the new sb */
2143         security_sb_clone_mnt_opts(data->sb, s);
2144
2145         dprintk("<-- nfs_xdev_get_sb() = 0\n");
2146         return 0;
2147
2148 out_err_nosb:
2149         nfs_free_server(server);
2150 out_err_noserver:
2151         dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
2152         return error;
2153
2154 error_splat_super:
2155         up_write(&s->s_umount);
2156         deactivate_super(s);
2157         dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
2158         return error;
2159 }
2160
2161 #ifdef CONFIG_NFS_V4
2162
2163 /*
2164  * Finish setting up a cloned NFS4 superblock
2165  */
2166 static void nfs4_clone_super(struct super_block *sb,
2167                             const struct super_block *old_sb)
2168 {
2169         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2170         sb->s_blocksize = old_sb->s_blocksize;
2171         sb->s_maxbytes = old_sb->s_maxbytes;
2172         sb->s_time_gran = 1;
2173         sb->s_op = old_sb->s_op;
2174         nfs_initialise_sb(sb);
2175 }
2176
2177 /*
2178  * Set up an NFS4 superblock
2179  */
2180 static void nfs4_fill_super(struct super_block *sb)
2181 {
2182         sb->s_time_gran = 1;
2183         sb->s_op = &nfs4_sops;
2184         nfs_initialise_sb(sb);
2185 }
2186
2187 /*
2188  * Validate NFSv4 mount options
2189  */
2190 static int nfs4_validate_mount_data(void *options,
2191                                     struct nfs_parsed_mount_data *args,
2192                                     const char *dev_name)
2193 {
2194         struct sockaddr_in *ap;
2195         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2196         char *c;
2197
2198         if (data == NULL)
2199                 goto out_no_data;
2200
2201         args->rsize             = NFS_MAX_FILE_IO_SIZE;
2202         args->wsize             = NFS_MAX_FILE_IO_SIZE;
2203         args->acregmin          = NFS_DEF_ACREGMIN;
2204         args->acregmax          = NFS_DEF_ACREGMAX;
2205         args->acdirmin          = NFS_DEF_ACDIRMIN;
2206         args->acdirmax          = NFS_DEF_ACDIRMAX;
2207         args->nfs_server.port   = NFS_PORT; /* 2049 unless user set port= */
2208         args->auth_flavors[0]   = RPC_AUTH_UNIX;
2209         args->auth_flavor_len   = 0;
2210
2211         switch (data->version) {
2212         case 1:
2213                 ap = (struct sockaddr_in *)&args->nfs_server.address;
2214                 if (data->host_addrlen > sizeof(args->nfs_server.address))
2215                         goto out_no_address;
2216                 if (data->host_addrlen == 0)
2217                         goto out_no_address;
2218                 args->nfs_server.addrlen = data->host_addrlen;
2219                 if (copy_from_user(ap, data->host_addr, data->host_addrlen))
2220                         return -EFAULT;
2221                 if (!nfs_verify_server_address((struct sockaddr *)
2222                                                 &args->nfs_server.address))
2223                         goto out_no_address;
2224
2225                 if (data->auth_flavourlen) {
2226                         if (data->auth_flavourlen > 1)
2227                                 goto out_inval_auth;
2228                         if (copy_from_user(&args->auth_flavors[0],
2229                                            data->auth_flavours,
2230                                            sizeof(args->auth_flavors[0])))
2231                                 return -EFAULT;
2232                 }
2233
2234                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2235                 if (IS_ERR(c))
2236                         return PTR_ERR(c);
2237                 args->nfs_server.hostname = c;
2238
2239                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2240                 if (IS_ERR(c))
2241                         return PTR_ERR(c);
2242                 args->nfs_server.export_path = c;
2243                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2244
2245                 c = strndup_user(data->client_addr.data, 16);
2246                 if (IS_ERR(c))
2247                         return PTR_ERR(c);
2248                 args->client_address = c;
2249
2250                 /*
2251                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2252                  * can deal with.
2253                  */
2254
2255                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
2256                 args->rsize     = data->rsize;
2257                 args->wsize     = data->wsize;
2258                 args->timeo     = data->timeo;
2259                 args->retrans   = data->retrans;
2260                 args->acregmin  = data->acregmin;
2261                 args->acregmax  = data->acregmax;
2262                 args->acdirmin  = data->acdirmin;
2263                 args->acdirmax  = data->acdirmax;
2264                 args->nfs_server.protocol = data->proto;
2265                 nfs_validate_transport_protocol(args);
2266
2267                 break;
2268         default: {
2269                 int status;
2270
2271                 if (nfs_parse_mount_options((char *)options, args) == 0)
2272                         return -EINVAL;
2273
2274                 if (!nfs_verify_server_address((struct sockaddr *)
2275                                                 &args->nfs_server.address))
2276                         return -EINVAL;
2277
2278                 nfs_set_port((struct sockaddr *)&args->nfs_server.address,
2279                                 args->nfs_server.port);
2280
2281                 nfs_validate_transport_protocol(args);
2282
2283                 if (args->auth_flavor_len > 1)
2284                         goto out_inval_auth;
2285
2286                 if (args->client_address == NULL)
2287                         goto out_no_client_address;
2288
2289                 status = nfs_parse_devname(dev_name,
2290                                            &args->nfs_server.hostname,
2291                                            NFS4_MAXNAMLEN,
2292                                            &args->nfs_server.export_path,
2293                                            NFS4_MAXPATHLEN);
2294                 if (status < 0)
2295                         return status;
2296
2297                 break;
2298                 }
2299         }
2300
2301         return 0;
2302
2303 out_no_data:
2304         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2305         return -EINVAL;
2306
2307 out_inval_auth:
2308         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2309                  data->auth_flavourlen);
2310         return -EINVAL;
2311
2312 out_no_address:
2313         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2314         return -EINVAL;
2315
2316 out_no_client_address:
2317         dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
2318         return -EINVAL;
2319 }
2320
2321 /*
2322  * Get the superblock for an NFS4 mountpoint
2323  */
2324 static int nfs4_get_sb(struct file_system_type *fs_type,
2325         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2326 {
2327         struct nfs_parsed_mount_data *data;
2328         struct super_block *s;
2329         struct nfs_server *server;
2330         struct nfs_fh *mntfh;
2331         struct dentry *mntroot;
2332         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2333         struct nfs_sb_mountdata sb_mntdata = {
2334                 .mntflags = flags,
2335         };
2336         int error = -ENOMEM;
2337
2338         data = kzalloc(sizeof(*data), GFP_KERNEL);
2339         mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
2340         if (data == NULL || mntfh == NULL)
2341                 goto out_free_fh;
2342
2343         security_init_mnt_opts(&data->lsm_opts);
2344
2345         /* Validate the mount data */
2346         error = nfs4_validate_mount_data(raw_data, data, dev_name);
2347         if (error < 0)
2348                 goto out;
2349
2350         /* Get a volume representation */
2351         server = nfs4_create_server(data, mntfh);
2352         if (IS_ERR(server)) {
2353                 error = PTR_ERR(server);
2354                 goto out;
2355         }
2356         sb_mntdata.server = server;
2357
2358         if (server->flags & NFS4_MOUNT_UNSHARED)
2359                 compare_super = NULL;
2360
2361         /* Get a superblock - note that we may end up sharing one that already exists */
2362         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2363         if (IS_ERR(s)) {
2364                 error = PTR_ERR(s);
2365                 goto out_free;
2366         }
2367
2368         if (s->s_fs_info != server) {
2369                 nfs_free_server(server);
2370                 server = NULL;
2371         } else {
2372                 error = nfs_bdi_register(server);
2373                 if (error)
2374                         goto error_splat_super;
2375         }
2376
2377         if (!s->s_root) {
2378                 /* initial superblock/root creation */
2379                 nfs4_fill_super(s);
2380         }
2381
2382         mntroot = nfs4_get_root(s, mntfh);
2383         if (IS_ERR(mntroot)) {
2384                 error = PTR_ERR(mntroot);
2385                 goto error_splat_super;
2386         }
2387
2388         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2389         if (error)
2390                 goto error_splat_root;
2391
2392         s->s_flags |= MS_ACTIVE;
2393         mnt->mnt_sb = s;
2394         mnt->mnt_root = mntroot;
2395         error = 0;
2396
2397 out:
2398         kfree(data->client_address);
2399         kfree(data->nfs_server.export_path);
2400         kfree(data->nfs_server.hostname);
2401         security_free_mnt_opts(&data->lsm_opts);
2402 out_free_fh:
2403         kfree(mntfh);
2404         kfree(data);
2405         return error;
2406
2407 out_free:
2408         nfs_free_server(server);
2409         goto out;
2410
2411 error_splat_root:
2412         dput(mntroot);
2413 error_splat_super:
2414         up_write(&s->s_umount);
2415         deactivate_super(s);
2416         goto out;
2417 }
2418
2419 static void nfs4_kill_super(struct super_block *sb)
2420 {
2421         struct nfs_server *server = NFS_SB(sb);
2422
2423         nfs_return_all_delegations(sb);
2424         kill_anon_super(sb);
2425
2426         nfs4_renewd_prepare_shutdown(server);
2427         nfs_free_server(server);
2428 }
2429
2430 /*
2431  * Clone an NFS4 server record on xdev traversal (FSID-change)
2432  */
2433 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
2434                             const char *dev_name, void *raw_data,
2435                             struct vfsmount *mnt)
2436 {
2437         struct nfs_clone_mount *data = raw_data;
2438         struct super_block *s;
2439         struct nfs_server *server;
2440         struct dentry *mntroot;
2441         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2442         struct nfs_sb_mountdata sb_mntdata = {
2443                 .mntflags = flags,
2444         };
2445         int error;
2446
2447         dprintk("--> nfs4_xdev_get_sb()\n");
2448
2449         /* create a new volume representation */
2450         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2451         if (IS_ERR(server)) {
2452                 error = PTR_ERR(server);
2453                 goto out_err_noserver;
2454         }
2455         sb_mntdata.server = server;
2456
2457         if (server->flags & NFS4_MOUNT_UNSHARED)
2458                 compare_super = NULL;
2459
2460         /* Get a superblock - note that we may end up sharing one that already exists */
2461         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2462         if (IS_ERR(s)) {
2463                 error = PTR_ERR(s);
2464                 goto out_err_nosb;
2465         }
2466
2467         if (s->s_fs_info != server) {
2468                 nfs_free_server(server);
2469                 server = NULL;
2470         } else {
2471                 error = nfs_bdi_register(server);
2472                 if (error)
2473                         goto error_splat_super;
2474         }
2475
2476         if (!s->s_root) {
2477                 /* initial superblock/root creation */
2478                 nfs4_clone_super(s, data->sb);
2479         }
2480
2481         mntroot = nfs4_get_root(s, data->fh);
2482         if (IS_ERR(mntroot)) {
2483                 error = PTR_ERR(mntroot);
2484                 goto error_splat_super;
2485         }
2486         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2487                 dput(mntroot);
2488                 error = -ESTALE;
2489                 goto error_splat_super;
2490         }
2491
2492         s->s_flags |= MS_ACTIVE;
2493         mnt->mnt_sb = s;
2494         mnt->mnt_root = mntroot;
2495
2496         security_sb_clone_mnt_opts(data->sb, s);
2497
2498         dprintk("<-- nfs4_xdev_get_sb() = 0\n");
2499         return 0;
2500
2501 out_err_nosb:
2502         nfs_free_server(server);
2503 out_err_noserver:
2504         dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
2505         return error;
2506
2507 error_splat_super:
2508         up_write(&s->s_umount);
2509         deactivate_super(s);
2510         dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
2511         return error;
2512 }
2513
2514 /*
2515  * Create an NFS4 server record on referral traversal
2516  */
2517 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
2518                                 const char *dev_name, void *raw_data,
2519                                 struct vfsmount *mnt)
2520 {
2521         struct nfs_clone_mount *data = raw_data;
2522         struct super_block *s;
2523         struct nfs_server *server;
2524         struct dentry *mntroot;
2525         struct nfs_fh mntfh;
2526         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2527         struct nfs_sb_mountdata sb_mntdata = {
2528                 .mntflags = flags,
2529         };
2530         int error;
2531
2532         dprintk("--> nfs4_referral_get_sb()\n");
2533
2534         /* create a new volume representation */
2535         server = nfs4_create_referral_server(data, &mntfh);
2536         if (IS_ERR(server)) {
2537                 error = PTR_ERR(server);
2538                 goto out_err_noserver;
2539         }
2540         sb_mntdata.server = server;
2541
2542         if (server->flags & NFS4_MOUNT_UNSHARED)
2543                 compare_super = NULL;
2544
2545         /* Get a superblock - note that we may end up sharing one that already exists */
2546         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2547         if (IS_ERR(s)) {
2548                 error = PTR_ERR(s);
2549                 goto out_err_nosb;
2550         }
2551
2552         if (s->s_fs_info != server) {
2553                 nfs_free_server(server);
2554                 server = NULL;
2555         } else {
2556                 error = nfs_bdi_register(server);
2557                 if (error)
2558                         goto error_splat_super;
2559         }
2560
2561         if (!s->s_root) {
2562                 /* initial superblock/root creation */
2563                 nfs4_fill_super(s);
2564         }
2565
2566         mntroot = nfs4_get_root(s, &mntfh);
2567         if (IS_ERR(mntroot)) {
2568                 error = PTR_ERR(mntroot);
2569                 goto error_splat_super;
2570         }
2571         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2572                 dput(mntroot);
2573                 error = -ESTALE;
2574                 goto error_splat_super;
2575         }
2576
2577         s->s_flags |= MS_ACTIVE;
2578         mnt->mnt_sb = s;
2579         mnt->mnt_root = mntroot;
2580
2581         security_sb_clone_mnt_opts(data->sb, s);
2582
2583         dprintk("<-- nfs4_referral_get_sb() = 0\n");
2584         return 0;
2585
2586 out_err_nosb:
2587         nfs_free_server(server);
2588 out_err_noserver:
2589         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
2590         return error;
2591
2592 error_splat_super:
2593         up_write(&s->s_umount);
2594         deactivate_super(s);
2595         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
2596         return error;
2597 }
2598
2599 #endif /* CONFIG_NFS_V4 */