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.Cox@linux.org>, 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=" NIP6_FMT,
 472                                 NIP6(sin6->sin6_addr));
 473                 break;
 474         }
 475         default:
 476                 if (showdefaults)
 477                         seq_printf(m, ",mountaddr=unspecified");
 478         }
 479
 480         if (nfss->mountd_version || showdefaults)
 481                 seq_printf(m, ",mountvers=%u", nfss->mountd_version);
 482         if (nfss->mountd_port || showdefaults)
 483                 seq_printf(m, ",mountport=%u", nfss->mountd_port);
 484
 485         switch (nfss->mountd_protocol) {
 486         case IPPROTO_UDP:
 487                 seq_printf(m, ",mountproto=udp");
 488                 break;
 489         case IPPROTO_TCP:
 490                 seq_printf(m, ",mountproto=tcp");
 491                 break;
 492         default:
 493                 if (showdefaults)
 494                         seq_printf(m, ",mountproto=auto");
 495         }
 496 }
 497
 498 /*
 499  * Describe the mount options in force on this server representation
 500  */
 501 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
 502                                    int showdefaults)
 503 {
 504         static const struct proc_nfs_info {
 505                 int flag;
 506                 const char *str;
 507                 const char *nostr;
 508         } nfs_info[] = {
 509                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 510                 { NFS_MOUNT_INTR, ",intr", ",nointr" },
 511                 { NFS_MOUNT_POSIX, ",posix", "" },
 512                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 513                 { NFS_MOUNT_NOAC, ",noac", "" },
 514                 { NFS_MOUNT_NONLM, ",nolock", "" },
 515                 { NFS_MOUNT_NOACL, ",noacl", "" },
 516                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 517                 { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
 518                 { 0, NULL, NULL }
 519         };
 520         const struct proc_nfs_info *nfs_infop;
 521         struct nfs_client *clp = nfss->nfs_client;
 522         u32 version = clp->rpc_ops->version;
 523
 524         seq_printf(m, ",vers=%u", version);
 525         seq_printf(m, ",rsize=%u", nfss->rsize);
 526         seq_printf(m, ",wsize=%u", nfss->wsize);
 527         if (nfss->bsize != 0)
 528                 seq_printf(m, ",bsize=%u", nfss->bsize);
 529         seq_printf(m, ",namlen=%u", nfss->namelen);
 530         if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
 531                 seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
 532         if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
 533                 seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
 534         if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
 535                 seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
 536         if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
 537                 seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
 538         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 539                 if (nfss->flags & nfs_infop->flag)
 540                         seq_puts(m, nfs_infop->str);
 541                 else
 542                         seq_puts(m, nfs_infop->nostr);
 543         }
 544         seq_printf(m, ",proto=%s",
 545                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
 546         if (version == 4) {
 547                 if (nfss->port != NFS_PORT)
 548                         seq_printf(m, ",port=%u", nfss->port);
 549         } else
 550                 if (nfss->port)
 551                         seq_printf(m, ",port=%u", nfss->port);
 552
 553         seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
 554         seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
 555         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 556
 557         if (version != 4)
 558                 nfs_show_mountd_options(m, nfss, showdefaults);
 559
 560 #ifdef CONFIG_NFS_V4
 561         if (clp->rpc_ops->version == 4)
 562                 seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
 563 #endif
 564 }
 565
 566 /*
 567  * Describe the mount options on this VFS mountpoint
 568  */
 569 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 570 {
 571         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 572
 573         nfs_show_mount_options(m, nfss, 0);
 574
 575         seq_printf(m, ",addr=%s",
 576                         rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
 577                                                         RPC_DISPLAY_ADDR));
 578
 579         return 0;
 580 }
 581
 582 /*
 583  * Present statistical information for this VFS mountpoint
 584  */
 585 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 586 {
 587         int i, cpu;
 588         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 589         struct rpc_auth *auth = nfss->client->cl_auth;
 590         struct nfs_iostats totals = { };
 591
 592         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 593
 594         /*
 595          * Display all mount option settings
 596          */
 597         seq_printf(m, "\n\topts:\t");
 598         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 599         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 600         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 601         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 602         nfs_show_mount_options(m, nfss, 1);
 603
 604         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 605
 606         seq_printf(m, "\n\tcaps:\t");
 607         seq_printf(m, "caps=0x%x", nfss->caps);
 608         seq_printf(m, ",wtmult=%u", nfss->wtmult);
 609         seq_printf(m, ",dtsize=%u", nfss->dtsize);
 610         seq_printf(m, ",bsize=%u", nfss->bsize);
 611         seq_printf(m, ",namlen=%u", nfss->namelen);
 612
 613 #ifdef CONFIG_NFS_V4
 614         if (nfss->nfs_client->rpc_ops->version == 4) {
 615                 seq_printf(m, "\n\tnfsv4:\t");
 616                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 617                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 618                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 619         }
 620 #endif
 621
 622         /*
 623          * Display security flavor in effect for this mount
 624          */
 625         seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
 626         if (auth->au_flavor)
 627                 seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
 628
 629         /*
 630          * Display superblock I/O counters
 631          */
 632         for_each_possible_cpu(cpu) {
 633                 struct nfs_iostats *stats;
 634
 635                 preempt_disable();
 636                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 637
 638                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 639                         totals.events[i] += stats->events[i];
 640                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 641                         totals.bytes[i] += stats->bytes[i];
 642
 643                 preempt_enable();
 644         }
 645
 646         seq_printf(m, "\n\tevents:\t");
 647         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 648                 seq_printf(m, "%lu ", totals.events[i]);
 649         seq_printf(m, "\n\tbytes:\t");
 650         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 651                 seq_printf(m, "%Lu ", totals.bytes[i]);
 652         seq_printf(m, "\n");
 653
 654         rpc_print_iostats(m, nfss->client);
 655
 656         return 0;
 657 }
 658
 659 /*
 660  * Begin unmount by attempting to remove all automounted mountpoints we added
 661  * in response to xdev traversals and referrals
 662  */
 663 static void nfs_umount_begin(struct super_block *sb)
 664 {
 665         struct nfs_server *server = NFS_SB(sb);
 666         struct rpc_clnt *rpc;
 667
 668         /* -EIO all pending I/O */
 669         rpc = server->client_acl;
 670         if (!IS_ERR(rpc))
 671                 rpc_killall_tasks(rpc);
 672         rpc = server->client;
 673         if (!IS_ERR(rpc))
 674                 rpc_killall_tasks(rpc);
 675 }
 676
 677 /*
 678  * Sanity-check a server address provided by the mount command.
 679  *
 680  * Address family must be initialized, and address must not be
 681  * the ANY address for that family.
 682  */
 683 static int nfs_verify_server_address(struct sockaddr *addr)
 684 {
 685         switch (addr->sa_family) {
 686         case AF_INET: {
 687                 struct sockaddr_in *sa = (struct sockaddr_in *)addr;
 688                 return sa->sin_addr.s_addr != htonl(INADDR_ANY);
 689         }
 690         case AF_INET6: {
 691                 struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
 692                 return !ipv6_addr_any(sa);
 693         }
 694         }
 695
 696         return 0;
 697 }
 698
 699 static void nfs_parse_ipv4_address(char *string, size_t str_len,
 700                                    struct sockaddr *sap, size_t *addr_len)
 701 {
 702         struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 703         u8 *addr = (u8 *)&sin->sin_addr.s_addr;
 704
 705         if (str_len <= INET_ADDRSTRLEN) {
 706                 dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
 707                                 (int)str_len, string);
 708
 709                 sin->sin_family = AF_INET;
 710                 *addr_len = sizeof(*sin);
 711                 if (in4_pton(string, str_len, addr, '\0', NULL))
 712                         return;
 713         }
 714
 715         sap->sa_family = AF_UNSPEC;
 716         *addr_len = 0;
 717 }
 718
 719 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 720 static int nfs_parse_ipv6_scope_id(const char *string, const size_t str_len,
 721                                    const char *delim,
 722                                    struct sockaddr_in6 *sin6)
 723 {
 724         char *p;
 725         size_t len;
 726
 727         if ((string + str_len) == delim)
 728                 return 1;
 729
 730         if (*delim != IPV6_SCOPE_DELIMITER)
 731                 return 0;
 732
 733         if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
 734                 return 0;
 735
 736         len = (string + str_len) - delim - 1;
 737         p = kstrndup(delim + 1, len, GFP_KERNEL);
 738         if (p) {
 739                 unsigned long scope_id = 0;
 740                 struct net_device *dev;
 741
 742                 dev = dev_get_by_name(&init_net, p);
 743                 if (dev != NULL) {
 744                         scope_id = dev->ifindex;
 745                         dev_put(dev);
 746                 } else {
 747                         if (strict_strtoul(p, 10, &scope_id) == 0) {
 748                                 kfree(p);
 749                                 return 0;
 750                         }
 751                 }
 752
 753                 kfree(p);
 754
 755                 sin6->sin6_scope_id = scope_id;
 756                 dfprintk(MOUNT, "NFS: IPv6 scope ID = %lu\n", scope_id);
 757                 return 1;
 758         }
 759
 760         return 0;
 761 }
 762
 763 static void nfs_parse_ipv6_address(char *string, size_t str_len,
 764                                    struct sockaddr *sap, size_t *addr_len)
 765 {
 766         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 767         u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
 768         const char *delim;
 769
 770         if (str_len <= INET6_ADDRSTRLEN) {
 771                 dfprintk(MOUNT, "NFS: parsing IPv6 address %*s\n",
 772                                 (int)str_len, string);
 773
 774                 sin6->sin6_family = AF_INET6;
 775                 *addr_len = sizeof(*sin6);
 776                 if (in6_pton(string, str_len, addr,
 777                                         IPV6_SCOPE_DELIMITER, &delim) != 0) {
 778                         if (nfs_parse_ipv6_scope_id(string, str_len,
 779                                                         delim, sin6) != 0)
 780                                 return;
 781                 }
 782         }
 783
 784         sap->sa_family = AF_UNSPEC;
 785         *addr_len = 0;
 786 }
 787 #else
 788 static void nfs_parse_ipv6_address(char *string, size_t str_len,
 789                                    struct sockaddr *sap, size_t *addr_len)
 790 {
 791         sap->sa_family = AF_UNSPEC;
 792         *addr_len = 0;
 793 }
 794 #endif
 795
 796 /*
 797  * Construct a sockaddr based on the contents of a string that contains
 798  * an IP address in presentation format.
 799  *
 800  * If there is a problem constructing the new sockaddr, set the address
 801  * family to AF_UNSPEC.
 802  */
 803 void nfs_parse_ip_address(char *string, size_t str_len,
 804                                  struct sockaddr *sap, size_t *addr_len)
 805 {
 806         unsigned int i, colons;
 807
 808         colons = 0;
 809         for (i = 0; i < str_len; i++)
 810                 if (string[i] == ':')
 811                         colons++;
 812
 813         if (colons >= 2)
 814                 nfs_parse_ipv6_address(string, str_len, sap, addr_len);
 815         else
 816                 nfs_parse_ipv4_address(string, str_len, sap, addr_len);
 817 }
 818
 819 /*
 820  * Sanity check the NFS transport protocol.
 821  *
 822  */
 823 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
 824 {
 825         switch (mnt->nfs_server.protocol) {
 826         case XPRT_TRANSPORT_UDP:
 827         case XPRT_TRANSPORT_TCP:
 828         case XPRT_TRANSPORT_RDMA:
 829                 break;
 830         default:
 831                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 832         }
 833 }
 834
 835 /*
 836  * For text based NFSv2/v3 mounts, the mount protocol transport default
 837  * settings should depend upon the specified NFS transport.
 838  */
 839 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
 840 {
 841         nfs_validate_transport_protocol(mnt);
 842
 843         if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
 844             mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
 845                         return;
 846         switch (mnt->nfs_server.protocol) {
 847         case XPRT_TRANSPORT_UDP:
 848                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 849                 break;
 850         case XPRT_TRANSPORT_TCP:
 851         case XPRT_TRANSPORT_RDMA:
 852                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 853         }
 854 }
 855
 856 /*
 857  * Parse the value of the 'sec=' option.
 858  *
 859  * The flavor_len setting is for v4 mounts.
 860  */
 861 static int nfs_parse_security_flavors(char *value,
 862                                       struct nfs_parsed_mount_data *mnt)
 863 {
 864         substring_t args[MAX_OPT_ARGS];
 865
 866         dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
 867
 868         switch (match_token(value, nfs_secflavor_tokens, args)) {
 869         case Opt_sec_none:
 870                 mnt->auth_flavor_len = 0;
 871                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 872                 break;
 873         case Opt_sec_sys:
 874                 mnt->auth_flavor_len = 0;
 875                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 876                 break;
 877         case Opt_sec_krb5:
 878                 mnt->auth_flavor_len = 1;
 879                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 880                 break;
 881         case Opt_sec_krb5i:
 882                 mnt->auth_flavor_len = 1;
 883                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 884                 break;
 885         case Opt_sec_krb5p:
 886                 mnt->auth_flavor_len = 1;
 887                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 888                 break;
 889         case Opt_sec_lkey:
 890                 mnt->auth_flavor_len = 1;
 891                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 892                 break;
 893         case Opt_sec_lkeyi:
 894                 mnt->auth_flavor_len = 1;
 895                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 896                 break;
 897         case Opt_sec_lkeyp:
 898                 mnt->auth_flavor_len = 1;
 899                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 900                 break;
 901         case Opt_sec_spkm:
 902                 mnt->auth_flavor_len = 1;
 903                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 904                 break;
 905         case Opt_sec_spkmi:
 906                 mnt->auth_flavor_len = 1;
 907                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 908                 break;
 909         case Opt_sec_spkmp:
 910                 mnt->auth_flavor_len = 1;
 911                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 912                 break;
 913         default:
 914                 return 0;
 915         }
 916
 917         return 1;
 918 }
 919
 920 static void nfs_parse_invalid_value(const char *option)
 921 {
 922         dfprintk(MOUNT, "NFS:   bad value specified for %s option\n", option);
 923 }
 924
 925 /*
 926  * Error-check and convert a string of mount options from user space into
 927  * a data structure.  The whole mount string is processed; bad options are
 928  * skipped as they are encountered.  If there were no errors, return 1;
 929  * otherwise return 0 (zero).
 930  */
 931 static int nfs_parse_mount_options(char *raw,
 932                                    struct nfs_parsed_mount_data *mnt)
 933 {
 934         char *p, *string, *secdata;
 935         int rc, sloppy = 0, errors = 0;
 936
 937         if (!raw) {
 938                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 939                 return 1;
 940         }
 941         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 942
 943         secdata = alloc_secdata();
 944         if (!secdata)
 945                 goto out_nomem;
 946
 947         rc = security_sb_copy_data(raw, secdata);
 948         if (rc)
 949                 goto out_security_failure;
 950
 951         rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
 952         if (rc)
 953                 goto out_security_failure;
 954
 955         free_secdata(secdata);
 956
 957         while ((p = strsep(&raw, ",")) != NULL) {
 958                 substring_t args[MAX_OPT_ARGS];
 959                 int option, token;
 960
 961                 if (!*p)
 962                         continue;
 963
 964                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
 965
 966                 token = match_token(p, nfs_mount_option_tokens, args);
 967                 switch (token) {
 968
 969                 /*
 970                  * boolean options:  foo/nofoo
 971                  */
 972                 case Opt_soft:
 973                         mnt->flags |= NFS_MOUNT_SOFT;
 974                         break;
 975                 case Opt_hard:
 976                         mnt->flags &= ~NFS_MOUNT_SOFT;
 977                         break;
 978                 case Opt_posix:
 979                         mnt->flags |= NFS_MOUNT_POSIX;
 980                         break;
 981                 case Opt_noposix:
 982                         mnt->flags &= ~NFS_MOUNT_POSIX;
 983                         break;
 984                 case Opt_cto:
 985                         mnt->flags &= ~NFS_MOUNT_NOCTO;
 986                         break;
 987                 case Opt_nocto:
 988                         mnt->flags |= NFS_MOUNT_NOCTO;
 989                         break;
 990                 case Opt_ac:
 991                         mnt->flags &= ~NFS_MOUNT_NOAC;
 992                         break;
 993                 case Opt_noac:
 994                         mnt->flags |= NFS_MOUNT_NOAC;
 995                         break;
 996                 case Opt_lock:
 997                         mnt->flags &= ~NFS_MOUNT_NONLM;
 998                         break;
 999                 case Opt_nolock:
1000                         mnt->flags |= NFS_MOUNT_NONLM;
1001                         break;
1002                 case Opt_v2:
1003                         mnt->flags &= ~NFS_MOUNT_VER3;
1004                         break;
1005                 case Opt_v3:
1006                         mnt->flags |= NFS_MOUNT_VER3;
1007                         break;
1008                 case Opt_udp:
1009                         mnt->flags &= ~NFS_MOUNT_TCP;
1010                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1011                         break;
1012                 case Opt_tcp:
1013                         mnt->flags |= NFS_MOUNT_TCP;
1014                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1015                         break;
1016                 case Opt_rdma:
1017                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1018                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1019                         break;
1020                 case Opt_acl:
1021                         mnt->flags &= ~NFS_MOUNT_NOACL;
1022                         break;
1023                 case Opt_noacl:
1024                         mnt->flags |= NFS_MOUNT_NOACL;
1025                         break;
1026                 case Opt_rdirplus:
1027                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1028                         break;
1029                 case Opt_nordirplus:
1030                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1031                         break;
1032                 case Opt_sharecache:
1033                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
1034                         break;
1035                 case Opt_nosharecache:
1036                         mnt->flags |= NFS_MOUNT_UNSHARED;
1037                         break;
1038
1039                 /*
1040                  * options that take numeric values
1041                  */
1042                 case Opt_port:
1043                         if (match_int(args, &option) ||
1044                             option < 0 || option > USHORT_MAX) {
1045                                 errors++;
1046                                 nfs_parse_invalid_value("port");
1047                         } else
1048                                 mnt->nfs_server.port = option;
1049                         break;
1050                 case Opt_rsize:
1051                         if (match_int(args, &option) || option < 0) {
1052                                 errors++;
1053                                 nfs_parse_invalid_value("rsize");
1054                         } else
1055                                 mnt->rsize = option;
1056                         break;
1057                 case Opt_wsize:
1058                         if (match_int(args, &option) || option < 0) {
1059                                 errors++;
1060                                 nfs_parse_invalid_value("wsize");
1061                         } else
1062                                 mnt->wsize = option;
1063                         break;
1064                 case Opt_bsize:
1065                         if (match_int(args, &option) || option < 0) {
1066                                 errors++;
1067                                 nfs_parse_invalid_value("bsize");
1068                         } else
1069                                 mnt->bsize = option;
1070                         break;
1071                 case Opt_timeo:
1072                         if (match_int(args, &option) || option <= 0) {
1073                                 errors++;
1074                                 nfs_parse_invalid_value("timeo");
1075                         } else
1076                                 mnt->timeo = option;
1077                         break;
1078                 case Opt_retrans:
1079                         if (match_int(args, &option) || option <= 0) {
1080                                 errors++;
1081                                 nfs_parse_invalid_value("retrans");
1082                         } else
1083                                 mnt->retrans = option;
1084                         break;
1085                 case Opt_acregmin:
1086                         if (match_int(args, &option) || option < 0) {
1087                                 errors++;
1088                                 nfs_parse_invalid_value("acregmin");
1089                         } else
1090                                 mnt->acregmin = option;
1091                         break;
1092                 case Opt_acregmax:
1093                         if (match_int(args, &option) || option < 0) {
1094                                 errors++;
1095                                 nfs_parse_invalid_value("acregmax");
1096                         } else
1097                                 mnt->acregmax = option;
1098                         break;
1099                 case Opt_acdirmin:
1100                         if (match_int(args, &option) || option < 0) {
1101                                 errors++;
1102                                 nfs_parse_invalid_value("acdirmin");
1103                         } else
1104                                 mnt->acdirmin = option;
1105                         break;
1106                 case Opt_acdirmax:
1107                         if (match_int(args, &option) || option < 0) {
1108                                 errors++;
1109                                 nfs_parse_invalid_value("acdirmax");
1110                         } else
1111                                 mnt->acdirmax = option;
1112                         break;
1113                 case Opt_actimeo:
1114                         if (match_int(args, &option) || option < 0) {
1115                                 errors++;
1116                                 nfs_parse_invalid_value("actimeo");
1117                         } else
1118                                 mnt->acregmin = mnt->acregmax =
1119                                 mnt->acdirmin = mnt->acdirmax = option;
1120                         break;
1121                 case Opt_namelen:
1122                         if (match_int(args, &option) || option < 0) {
1123                                 errors++;
1124                                 nfs_parse_invalid_value("namlen");
1125                         } else
1126                                 mnt->namlen = option;
1127                         break;
1128                 case Opt_mountport:
1129                         if (match_int(args, &option) ||
1130                             option < 0 || option > USHORT_MAX) {
1131                                 errors++;
1132                                 nfs_parse_invalid_value("mountport");
1133                         } else
1134                                 mnt->mount_server.port = option;
1135                         break;
1136                 case Opt_mountvers:
1137                         if (match_int(args, &option) ||
1138                             option < NFS_MNT_VERSION ||
1139                             option > NFS_MNT3_VERSION) {
1140                                 errors++;
1141                                 nfs_parse_invalid_value("mountvers");
1142                         } else
1143                                 mnt->mount_server.version = option;
1144                         break;
1145                 case Opt_nfsvers:
1146                         if (match_int(args, &option)) {
1147                                 errors++;
1148                                 nfs_parse_invalid_value("nfsvers");
1149                                 break;
1150                         }
1151                         switch (option) {
1152                         case NFS2_VERSION:
1153                                 mnt->flags &= ~NFS_MOUNT_VER3;
1154                                 break;
1155                         case NFS3_VERSION:
1156                                 mnt->flags |= NFS_MOUNT_VER3;
1157                                 break;
1158                         default:
1159                                 errors++;
1160                                 nfs_parse_invalid_value("nfsvers");
1161                         }
1162                         break;
1163
1164                 /*
1165                  * options that take text values
1166                  */
1167                 case Opt_sec:
1168                         string = match_strdup(args);
1169                         if (string == NULL)
1170                                 goto out_nomem;
1171                         rc = nfs_parse_security_flavors(string, mnt);
1172                         kfree(string);
1173                         if (!rc) {
1174                                 errors++;
1175                                 dfprintk(MOUNT, "NFS:   unrecognized "
1176                                                 "security flavor\n");
1177                         }
1178                         break;
1179                 case Opt_proto:
1180                         string = match_strdup(args);
1181                         if (string == NULL)
1182                                 goto out_nomem;
1183                         token = match_token(string,
1184                                             nfs_xprt_protocol_tokens, args);
1185                         kfree(string);
1186
1187                         switch (token) {
1188                         case Opt_xprt_udp:
1189                                 mnt->flags &= ~NFS_MOUNT_TCP;
1190                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1191                                 break;
1192                         case Opt_xprt_tcp:
1193                                 mnt->flags |= NFS_MOUNT_TCP;
1194                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1195                                 break;
1196                         case Opt_xprt_rdma:
1197                                 /* vector side protocols to TCP */
1198                                 mnt->flags |= NFS_MOUNT_TCP;
1199                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1200                                 break;
1201                         default:
1202                                 errors++;
1203                                 dfprintk(MOUNT, "NFS:   unrecognized "
1204                                                 "transport protocol\n");
1205                         }
1206                         break;
1207                 case Opt_mountproto:
1208                         string = match_strdup(args);
1209                         if (string == NULL)
1210                                 goto out_nomem;
1211                         token = match_token(string,
1212                                             nfs_xprt_protocol_tokens, args);
1213                         kfree(string);
1214
1215                         switch (token) {
1216                         case Opt_xprt_udp:
1217                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1218                                 break;
1219                         case Opt_xprt_tcp:
1220                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1221                                 break;
1222                         case Opt_xprt_rdma: /* not used for side protocols */
1223                         default:
1224                                 errors++;
1225                                 dfprintk(MOUNT, "NFS:   unrecognized "
1226                                                 "transport protocol\n");
1227                         }
1228                         break;
1229                 case Opt_addr:
1230                         string = match_strdup(args);
1231                         if (string == NULL)
1232                                 goto out_nomem;
1233                         nfs_parse_ip_address(string, strlen(string),
1234                                              (struct sockaddr *)
1235                                                 &mnt->nfs_server.address,
1236                                              &mnt->nfs_server.addrlen);
1237                         kfree(string);
1238                         break;
1239                 case Opt_clientaddr:
1240                         string = match_strdup(args);
1241                         if (string == NULL)
1242                                 goto out_nomem;
1243                         kfree(mnt->client_address);
1244                         mnt->client_address = string;
1245                         break;
1246                 case Opt_mounthost:
1247                         string = match_strdup(args);
1248                         if (string == NULL)
1249                                 goto out_nomem;
1250                         kfree(mnt->mount_server.hostname);
1251                         mnt->mount_server.hostname = string;
1252                         break;
1253                 case Opt_mountaddr:
1254                         string = match_strdup(args);
1255                         if (string == NULL)
1256                                 goto out_nomem;
1257                         nfs_parse_ip_address(string, strlen(string),
1258                                              (struct sockaddr *)
1259                                                 &mnt->mount_server.address,
1260                                              &mnt->mount_server.addrlen);
1261                         kfree(string);
1262                         break;
1263                 case Opt_lookupcache:
1264                         string = match_strdup(args);
1265                         if (string == NULL)
1266                                 goto out_nomem;
1267                         token = match_token(string,
1268                                         nfs_lookupcache_tokens, args);
1269                         kfree(string);
1270                         switch (token) {
1271                                 case Opt_lookupcache_all:
1272                                         mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1273                                         break;
1274                                 case Opt_lookupcache_positive:
1275                                         mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1276                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1277                                         break;
1278                                 case Opt_lookupcache_none:
1279                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1280                                         break;
1281                                 default:
1282                                         errors++;
1283                                         dfprintk(MOUNT, "NFS:   invalid "
1284                                                         "lookupcache argument\n");
1285                         };
1286                         break;
1287
1288                 /*
1289                  * Special options
1290                  */
1291                 case Opt_sloppy:
1292                         sloppy = 1;
1293                         dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1294                         break;
1295                 case Opt_userspace:
1296                 case Opt_deprecated:
1297                         dfprintk(MOUNT, "NFS:   ignoring mount option "
1298                                         "'%s'\n", p);
1299                         break;
1300
1301                 default:
1302                         errors++;
1303                         dfprintk(MOUNT, "NFS:   unrecognized mount option "
1304                                         "'%s'\n", p);
1305                 }
1306         }
1307
1308         if (errors > 0) {
1309                 dfprintk(MOUNT, "NFS: parsing encountered %d error%s\n",
1310                                 errors, (errors == 1 ? "" : "s"));
1311                 if (!sloppy)
1312                         return 0;
1313         }
1314         return 1;
1315
1316 out_nomem:
1317         printk(KERN_INFO "NFS: not enough memory to parse option\n");
1318         return 0;
1319 out_security_failure:
1320         free_secdata(secdata);
1321         printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1322         return 0;
1323 }
1324
1325 /*
1326  * Use the remote server's MOUNT service to request the NFS file handle
1327  * corresponding to the provided path.
1328  */
1329 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1330                          struct nfs_fh *root_fh)
1331 {
1332         struct sockaddr *sap = (struct sockaddr *)&args->mount_server.address;
1333         char *hostname;
1334         int status;
1335
1336         if (args->mount_server.version == 0) {
1337                 if (args->flags & NFS_MOUNT_VER3)
1338                         args->mount_server.version = NFS_MNT3_VERSION;
1339                 else
1340                         args->mount_server.version = NFS_MNT_VERSION;
1341         }
1342
1343         if (args->mount_server.hostname)
1344                 hostname = args->mount_server.hostname;
1345         else
1346                 hostname = args->nfs_server.hostname;
1347
1348         /*
1349          * Construct the mount server's address.
1350          */
1351         if (args->mount_server.address.ss_family == AF_UNSPEC) {
1352                 memcpy(sap, &args->nfs_server.address,
1353                        args->nfs_server.addrlen);
1354                 args->mount_server.addrlen = args->nfs_server.addrlen;
1355         }
1356
1357         /*
1358          * autobind will be used if mount_server.port == 0
1359          */
1360         nfs_set_port(sap, args->mount_server.port);
1361
1362         /*
1363          * Now ask the mount server to map our export path
1364          * to a file handle.
1365          */
1366         status = nfs_mount(sap,
1367                            args->mount_server.addrlen,
1368                            hostname,
1369                            args->nfs_server.export_path,
1370                            args->mount_server.version,
1371                            args->mount_server.protocol,
1372                            root_fh);
1373         if (status == 0)
1374                 return 0;
1375
1376         dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1377                         hostname, status);
1378         return status;
1379 }
1380
1381 static int nfs_parse_simple_hostname(const char *dev_name,
1382                                      char **hostname, size_t maxnamlen,
1383                                      char **export_path, size_t maxpathlen)
1384 {
1385         size_t len;
1386         char *colon, *comma;
1387
1388         colon = strchr(dev_name, ':');
1389         if (colon == NULL)
1390                 goto out_bad_devname;
1391
1392         len = colon - dev_name;
1393         if (len > maxnamlen)
1394                 goto out_hostname;
1395
1396         /* N.B. caller will free nfs_server.hostname in all cases */
1397         *hostname = kstrndup(dev_name, len, GFP_KERNEL);
1398         if (!*hostname)
1399                 goto out_nomem;
1400
1401         /* kill possible hostname list: not supported */
1402         comma = strchr(*hostname, ',');
1403         if (comma != NULL) {
1404                 if (comma == *hostname)
1405                         goto out_bad_devname;
1406                 *comma = '\0';
1407         }
1408
1409         colon++;
1410         len = strlen(colon);
1411         if (len > maxpathlen)
1412                 goto out_path;
1413         *export_path = kstrndup(colon, len, GFP_KERNEL);
1414         if (!*export_path)
1415                 goto out_nomem;
1416
1417         dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1418         return 0;
1419
1420 out_bad_devname:
1421         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1422         return -EINVAL;
1423
1424 out_nomem:
1425         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1426         return -ENOMEM;
1427
1428 out_hostname:
1429         dfprintk(MOUNT, "NFS: server hostname too long\n");
1430         return -ENAMETOOLONG;
1431
1432 out_path:
1433         dfprintk(MOUNT, "NFS: export pathname too long\n");
1434         return -ENAMETOOLONG;
1435 }
1436
1437 /*
1438  * Hostname has square brackets around it because it contains one or
1439  * more colons.  We look for the first closing square bracket, and a
1440  * colon must follow it.
1441  */
1442 static int nfs_parse_protected_hostname(const char *dev_name,
1443                                         char **hostname, size_t maxnamlen,
1444                                         char **export_path, size_t maxpathlen)
1445 {
1446         size_t len;
1447         char *start, *end;
1448
1449         start = (char *)(dev_name + 1);
1450
1451         end = strchr(start, ']');
1452         if (end == NULL)
1453                 goto out_bad_devname;
1454         if (*(end + 1) != ':')
1455                 goto out_bad_devname;
1456
1457         len = end - start;
1458         if (len > maxnamlen)
1459                 goto out_hostname;
1460
1461         /* N.B. caller will free nfs_server.hostname in all cases */
1462         *hostname = kstrndup(start, len, GFP_KERNEL);
1463         if (*hostname == NULL)
1464                 goto out_nomem;
1465
1466         end += 2;
1467         len = strlen(end);
1468         if (len > maxpathlen)
1469                 goto out_path;
1470         *export_path = kstrndup(end, len, GFP_KERNEL);
1471         if (!*export_path)
1472                 goto out_nomem;
1473
1474         return 0;
1475
1476 out_bad_devname:
1477         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1478         return -EINVAL;
1479
1480 out_nomem:
1481         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1482         return -ENOMEM;
1483
1484 out_hostname:
1485         dfprintk(MOUNT, "NFS: server hostname too long\n");
1486         return -ENAMETOOLONG;
1487
1488 out_path:
1489         dfprintk(MOUNT, "NFS: export pathname too long\n");
1490         return -ENAMETOOLONG;
1491 }
1492
1493 /*
1494  * Split "dev_name" into "hostname:export_path".
1495  *
1496  * The leftmost colon demarks the split between the server's hostname
1497  * and the export path.  If the hostname starts with a left square
1498  * bracket, then it may contain colons.
1499  *
1500  * Note: caller frees hostname and export path, even on error.
1501  */
1502 static int nfs_parse_devname(const char *dev_name,
1503                              char **hostname, size_t maxnamlen,
1504                              char **export_path, size_t maxpathlen)
1505 {
1506         if (*dev_name == '[')
1507                 return nfs_parse_protected_hostname(dev_name,
1508                                                     hostname, maxnamlen,
1509                                                     export_path, maxpathlen);
1510
1511         return nfs_parse_simple_hostname(dev_name,
1512                                          hostname, maxnamlen,
1513                                          export_path, maxpathlen);
1514 }
1515
1516 /*
1517  * Validate the NFS2/NFS3 mount data
1518  * - fills in the mount root filehandle
1519  *
1520  * For option strings, user space handles the following behaviors:
1521  *
1522  * + DNS: mapping server host name to IP address ("addr=" option)
1523  *
1524  * + failure mode: how to behave if a mount request can't be handled
1525  *   immediately ("fg/bg" option)
1526  *
1527  * + retry: how often to retry a mount request ("retry=" option)
1528  *
1529  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1530  *   mountproto=tcp after mountproto=udp, and so on
1531  */
1532 static int nfs_validate_mount_data(void *options,
1533                                    struct nfs_parsed_mount_data *args,
1534                                    struct nfs_fh *mntfh,
1535                                    const char *dev_name)
1536 {
1537         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1538
1539         if (data == NULL)
1540                 goto out_no_data;
1541
1542         args->flags             = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1543         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1544         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1545         args->acregmin          = NFS_DEF_ACREGMIN;
1546         args->acregmax          = NFS_DEF_ACREGMAX;
1547         args->acdirmin          = NFS_DEF_ACDIRMIN;
1548         args->acdirmax          = NFS_DEF_ACDIRMAX;
1549         args->mount_server.port = 0;    /* autobind unless user sets port */
1550         args->nfs_server.port   = 0;    /* autobind unless user sets port */
1551         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1552         args->auth_flavors[0]   = RPC_AUTH_UNIX;
1553
1554         switch (data->version) {
1555         case 1:
1556                 data->namlen = 0;
1557         case 2:
1558                 data->bsize = 0;
1559         case 3:
1560                 if (data->flags & NFS_MOUNT_VER3)
1561                         goto out_no_v3;
1562                 data->root.size = NFS2_FHSIZE;
1563                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1564         case 4:
1565                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1566                         goto out_no_sec;
1567         case 5:
1568                 memset(data->context, 0, sizeof(data->context));
1569         case 6:
1570                 if (data->flags & NFS_MOUNT_VER3) {
1571                         if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1572                                 goto out_invalid_fh;
1573                         mntfh->size = data->root.size;
1574                 } else
1575                         mntfh->size = NFS2_FHSIZE;
1576
1577
1578                 memcpy(mntfh->data, data->root.data, mntfh->size);
1579                 if (mntfh->size < sizeof(mntfh->data))
1580                         memset(mntfh->data + mntfh->size, 0,
1581                                sizeof(mntfh->data) - mntfh->size);
1582
1583                 /*
1584                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1585                  * can deal with.
1586                  */
1587                 args->flags             = data->flags & NFS_MOUNT_FLAGMASK;
1588                 args->rsize             = data->rsize;
1589                 args->wsize             = data->wsize;
1590                 args->timeo             = data->timeo;
1591                 args->retrans           = data->retrans;
1592                 args->acregmin          = data->acregmin;
1593                 args->acregmax          = data->acregmax;
1594                 args->acdirmin          = data->acdirmin;
1595                 args->acdirmax          = data->acdirmax;
1596
1597                 memcpy(&args->nfs_server.address, &data->addr,
1598                        sizeof(data->addr));
1599                 args->nfs_server.addrlen = sizeof(data->addr);
1600                 if (!nfs_verify_server_address((struct sockaddr *)
1601                                                 &args->nfs_server.address))
1602                         goto out_no_address;
1603
1604                 if (!(data->flags & NFS_MOUNT_TCP))
1605                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1606                 /* N.B. caller will free nfs_server.hostname in all cases */
1607                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1608                 args->namlen            = data->namlen;
1609                 args->bsize             = data->bsize;
1610
1611                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1612                         args->auth_flavors[0] = data->pseudoflavor;
1613                 if (!args->nfs_server.hostname)
1614                         goto out_nomem;
1615
1616                 /*
1617                  * The legacy version 6 binary mount data from userspace has a
1618                  * field used only to transport selinux information into the
1619                  * the kernel.  To continue to support that functionality we
1620                  * have a touch of selinux knowledge here in the NFS code. The
1621                  * userspace code converted context=blah to just blah so we are
1622                  * converting back to the full string selinux understands.
1623                  */
1624                 if (data->context[0]){
1625 #ifdef CONFIG_SECURITY_SELINUX
1626                         int rc;
1627                         char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1628                         if (!opts_str)
1629                                 return -ENOMEM;
1630                         strcpy(opts_str, "context=");
1631                         data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1632                         strcat(opts_str, &data->context[0]);
1633                         rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1634                         kfree(opts_str);
1635                         if (rc)
1636                                 return rc;
1637 #else
1638                         return -EINVAL;
1639 #endif
1640                 }
1641
1642                 break;
1643         default: {
1644                 int status;
1645
1646                 if (nfs_parse_mount_options((char *)options, args) == 0)
1647                         return -EINVAL;
1648
1649                 if (!nfs_verify_server_address((struct sockaddr *)
1650                                                 &args->nfs_server.address))
1651                         goto out_no_address;
1652
1653                 nfs_set_port((struct sockaddr *)&args->nfs_server.address,
1654                                 args->nfs_server.port);
1655
1656                 nfs_set_mount_transport_protocol(args);
1657
1658                 status = nfs_parse_devname(dev_name,
1659                                            &args->nfs_server.hostname,
1660                                            PAGE_SIZE,
1661                                            &args->nfs_server.export_path,
1662                                            NFS_MAXPATHLEN);
1663                 if (!status)
1664                         status = nfs_try_mount(args, mntfh);
1665
1666                 kfree(args->nfs_server.export_path);
1667                 args->nfs_server.export_path = NULL;
1668
1669                 if (status)
1670                         return status;
1671
1672                 break;
1673                 }
1674         }
1675
1676 #ifndef CONFIG_NFS_V3
1677         if (args->flags & NFS_MOUNT_VER3)
1678                 goto out_v3_not_compiled;
1679 #endif /* !CONFIG_NFS_V3 */
1680
1681         return 0;
1682
1683 out_no_data:
1684         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1685         return -EINVAL;
1686
1687 out_no_v3:
1688         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1689                  data->version);
1690         return -EINVAL;
1691
1692 out_no_sec:
1693         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1694         return -EINVAL;
1695
1696 #ifndef CONFIG_NFS_V3
1697 out_v3_not_compiled:
1698         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1699         return -EPROTONOSUPPORT;
1700 #endif /* !CONFIG_NFS_V3 */
1701
1702 out_nomem:
1703         dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1704         return -ENOMEM;
1705
1706 out_no_address:
1707         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1708         return -EINVAL;
1709
1710 out_invalid_fh:
1711         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1712         return -EINVAL;
1713 }
1714
1715 static int
1716 nfs_compare_remount_data(struct nfs_server *nfss,
1717                          struct nfs_parsed_mount_data *data)
1718 {
1719         if (data->flags != nfss->flags ||
1720             data->rsize != nfss->rsize ||
1721             data->wsize != nfss->wsize ||
1722             data->retrans != nfss->client->cl_timeout->to_retries ||
1723             data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
1724             data->acregmin != nfss->acregmin / HZ ||
1725             data->acregmax != nfss->acregmax / HZ ||
1726             data->acdirmin != nfss->acdirmin / HZ ||
1727             data->acdirmax != nfss->acdirmax / HZ ||
1728             data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
1729             data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
1730             memcmp(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1731                    data->nfs_server.addrlen) != 0)
1732                 return -EINVAL;
1733
1734         return 0;
1735 }
1736
1737 static int
1738 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
1739 {
1740         int error;
1741         struct nfs_server *nfss = sb->s_fs_info;
1742         struct nfs_parsed_mount_data *data;
1743         struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
1744         struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
1745         u32 nfsvers = nfss->nfs_client->rpc_ops->version;
1746
1747         /*
1748          * Userspace mount programs that send binary options generally send
1749          * them populated with default values. We have no way to know which
1750          * ones were explicitly specified. Fall back to legacy behavior and
1751          * just return success.
1752          */
1753         if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
1754             (nfsvers <= 3 && (!options || (options->version >= 1 &&
1755                                            options->version <= 6))))
1756                 return 0;
1757
1758         data = kzalloc(sizeof(*data), GFP_KERNEL);
1759         if (data == NULL)
1760                 return -ENOMEM;
1761
1762         /* fill out struct with values from existing mount */
1763         data->flags = nfss->flags;
1764         data->rsize = nfss->rsize;
1765         data->wsize = nfss->wsize;
1766         data->retrans = nfss->client->cl_timeout->to_retries;
1767         data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
1768         data->acregmin = nfss->acregmin / HZ;
1769         data->acregmax = nfss->acregmax / HZ;
1770         data->acdirmin = nfss->acdirmin / HZ;
1771         data->acdirmax = nfss->acdirmax / HZ;
1772         data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
1773         data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
1774         memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1775                 data->nfs_server.addrlen);
1776
1777         /* overwrite those values with any that were specified */
1778         error = nfs_parse_mount_options((char *)options, data);
1779         if (error < 0)
1780                 goto out;
1781
1782         /* compare new mount options with old ones */
1783         error = nfs_compare_remount_data(nfss, data);
1784 out:
1785         kfree(data);
1786         return error;
1787 }
1788
1789 /*
1790  * Initialise the common bits of the superblock
1791  */
1792 static inline void nfs_initialise_sb(struct super_block *sb)
1793 {
1794         struct nfs_server *server = NFS_SB(sb);
1795
1796         sb->s_magic = NFS_SUPER_MAGIC;
1797
1798         /* We probably want something more informative here */
1799         snprintf(sb->s_id, sizeof(sb->s_id),
1800                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1801
1802         if (sb->s_blocksize == 0)
1803                 sb->s_blocksize = nfs_block_bits(server->wsize,
1804                                                  &sb->s_blocksize_bits);
1805
1806         if (server->flags & NFS_MOUNT_NOAC)
1807                 sb->s_flags |= MS_SYNCHRONOUS;
1808
1809         nfs_super_set_maxbytes(sb, server->maxfilesize);
1810 }
1811
1812 /*
1813  * Finish setting up an NFS2/3 superblock
1814  */
1815 static void nfs_fill_super(struct super_block *sb,
1816                            struct nfs_parsed_mount_data *data)
1817 {
1818         struct nfs_server *server = NFS_SB(sb);
1819
1820         sb->s_blocksize_bits = 0;
1821         sb->s_blocksize = 0;
1822         if (data->bsize)
1823                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1824
1825         if (server->flags & NFS_MOUNT_VER3) {
1826                 /* The VFS shouldn't apply the umask to mode bits. We will do
1827                  * so ourselves when necessary.
1828                  */
1829                 sb->s_flags |= MS_POSIXACL;
1830                 sb->s_time_gran = 1;
1831         }
1832
1833         sb->s_op = &nfs_sops;
1834         nfs_initialise_sb(sb);
1835 }
1836
1837 /*
1838  * Finish setting up a cloned NFS2/3 superblock
1839  */
1840 static void nfs_clone_super(struct super_block *sb,
1841                             const struct super_block *old_sb)
1842 {
1843         struct nfs_server *server = NFS_SB(sb);
1844
1845         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1846         sb->s_blocksize = old_sb->s_blocksize;
1847         sb->s_maxbytes = old_sb->s_maxbytes;
1848
1849         if (server->flags & NFS_MOUNT_VER3) {
1850                 /* The VFS shouldn't apply the umask to mode bits. We will do
1851                  * so ourselves when necessary.
1852                  */
1853                 sb->s_flags |= MS_POSIXACL;
1854                 sb->s_time_gran = 1;
1855         }
1856
1857         sb->s_op = old_sb->s_op;
1858         nfs_initialise_sb(sb);
1859 }
1860
1861 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1862
1863 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1864 {
1865         const struct nfs_server *a = s->s_fs_info;
1866         const struct rpc_clnt *clnt_a = a->client;
1867         const struct rpc_clnt *clnt_b = b->client;
1868
1869         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1870                 goto Ebusy;
1871         if (a->nfs_client != b->nfs_client)
1872                 goto Ebusy;
1873         if (a->flags != b->flags)
1874                 goto Ebusy;
1875         if (a->wsize != b->wsize)
1876                 goto Ebusy;
1877         if (a->rsize != b->rsize)
1878                 goto Ebusy;
1879         if (a->acregmin != b->acregmin)
1880                 goto Ebusy;
1881         if (a->acregmax != b->acregmax)
1882                 goto Ebusy;
1883         if (a->acdirmin != b->acdirmin)
1884                 goto Ebusy;
1885         if (a->acdirmax != b->acdirmax)
1886                 goto Ebusy;
1887         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1888                 goto Ebusy;
1889         return 1;
1890 Ebusy:
1891         return 0;
1892 }
1893
1894 struct nfs_sb_mountdata {
1895         struct nfs_server *server;
1896         int mntflags;
1897 };
1898
1899 static int nfs_set_super(struct super_block *s, void *data)
1900 {
1901         struct nfs_sb_mountdata *sb_mntdata = data;
1902         struct nfs_server *server = sb_mntdata->server;
1903         int ret;
1904
1905         s->s_flags = sb_mntdata->mntflags;
1906         s->s_fs_info = server;
1907         ret = set_anon_super(s, server);
1908         if (ret == 0)
1909                 server->s_dev = s->s_dev;
1910         return ret;
1911 }
1912
1913 static int nfs_compare_super_address(struct nfs_server *server1,
1914                                      struct nfs_server *server2)
1915 {
1916         struct sockaddr *sap1, *sap2;
1917
1918         sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1919         sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1920
1921         if (sap1->sa_family != sap2->sa_family)
1922                 return 0;
1923
1924         switch (sap1->sa_family) {
1925         case AF_INET: {
1926                 struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1927                 struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1928                 if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1929                         return 0;
1930                 if (sin1->sin_port != sin2->sin_port)
1931                         return 0;
1932                 break;
1933         }
1934         case AF_INET6: {
1935                 struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1936                 struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1937                 if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1938                         return 0;
1939                 if (sin1->sin6_port != sin2->sin6_port)
1940                         return 0;
1941                 break;
1942         }
1943         default:
1944                 return 0;
1945         }
1946
1947         return 1;
1948 }
1949
1950 static int nfs_compare_super(struct super_block *sb, void *data)
1951 {
1952         struct nfs_sb_mountdata *sb_mntdata = data;
1953         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1954         int mntflags = sb_mntdata->mntflags;
1955
1956         if (!nfs_compare_super_address(old, server))
1957                 return 0;
1958         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1959         if (old->flags & NFS_MOUNT_UNSHARED)
1960                 return 0;
1961         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1962                 return 0;
1963         return nfs_compare_mount_options(sb, server, mntflags);
1964 }
1965
1966 static int nfs_bdi_register(struct nfs_server *server)
1967 {
1968         return bdi_register_dev(&server->backing_dev_info, server->s_dev);
1969 }
1970
1971 static int nfs_get_sb(struct file_system_type *fs_type,
1972         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1973 {
1974         struct nfs_server *server = NULL;
1975         struct super_block *s;
1976         struct nfs_parsed_mount_data *data;
1977         struct nfs_fh *mntfh;
1978         struct dentry *mntroot;
1979         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1980         struct nfs_sb_mountdata sb_mntdata = {
1981                 .mntflags = flags,
1982         };
1983         int error = -ENOMEM;
1984
1985         data = kzalloc(sizeof(*data), GFP_KERNEL);
1986         mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
1987         if (data == NULL || mntfh == NULL)
1988                 goto out_free_fh;
1989
1990         security_init_mnt_opts(&data->lsm_opts);
1991
1992         /* Validate the mount data */
1993         error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
1994         if (error < 0)
1995                 goto out;
1996
1997         /* Get a volume representation */
1998         server = nfs_create_server(data, mntfh);
1999         if (IS_ERR(server)) {
2000                 error = PTR_ERR(server);
2001                 goto out;
2002         }
2003         sb_mntdata.server = server;
2004
2005         if (server->flags & NFS_MOUNT_UNSHARED)
2006                 compare_super = NULL;
2007
2008         /* Get a superblock - note that we may end up sharing one that already exists */
2009         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2010         if (IS_ERR(s)) {
2011                 error = PTR_ERR(s);
2012                 goto out_err_nosb;
2013         }
2014
2015         if (s->s_fs_info != server) {
2016                 nfs_free_server(server);
2017                 server = NULL;
2018         } else {
2019                 error = nfs_bdi_register(server);
2020                 if (error)
2021                         goto error_splat_super;
2022         }
2023
2024         if (!s->s_root) {
2025                 /* initial superblock/root creation */
2026                 nfs_fill_super(s, data);
2027         }
2028
2029         mntroot = nfs_get_root(s, mntfh);
2030         if (IS_ERR(mntroot)) {
2031                 error = PTR_ERR(mntroot);
2032                 goto error_splat_super;
2033         }
2034
2035         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2036         if (error)
2037                 goto error_splat_root;
2038
2039         s->s_flags |= MS_ACTIVE;
2040         mnt->mnt_sb = s;
2041         mnt->mnt_root = mntroot;
2042         error = 0;
2043
2044 out:
2045         kfree(data->nfs_server.hostname);
2046         kfree(data->mount_server.hostname);
2047         security_free_mnt_opts(&data->lsm_opts);
2048 out_free_fh:
2049         kfree(mntfh);
2050         kfree(data);
2051         return error;
2052
2053 out_err_nosb:
2054         nfs_free_server(server);
2055         goto out;
2056
2057 error_splat_root:
2058         dput(mntroot);
2059 error_splat_super:
2060         up_write(&s->s_umount);
2061         deactivate_super(s);
2062         goto out;
2063 }
2064
2065 /*
2066  * Destroy an NFS2/3 superblock
2067  */
2068 static void nfs_kill_super(struct super_block *s)
2069 {
2070         struct nfs_server *server = NFS_SB(s);
2071
2072         bdi_unregister(&server->backing_dev_info);
2073         kill_anon_super(s);
2074         nfs_free_server(server);
2075 }
2076
2077 /*
2078  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2079  */
2080 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
2081                            const char *dev_name, void *raw_data,
2082                            struct vfsmount *mnt)
2083 {
2084         struct nfs_clone_mount *data = raw_data;
2085         struct super_block *s;
2086         struct nfs_server *server;
2087         struct dentry *mntroot;
2088         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2089         struct nfs_sb_mountdata sb_mntdata = {
2090                 .mntflags = flags,
2091         };
2092         int error;
2093
2094         dprintk("--> nfs_xdev_get_sb()\n");
2095
2096         /* create a new volume representation */
2097         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2098         if (IS_ERR(server)) {
2099                 error = PTR_ERR(server);
2100                 goto out_err_noserver;
2101         }
2102         sb_mntdata.server = server;
2103
2104         if (server->flags & NFS_MOUNT_UNSHARED)
2105                 compare_super = NULL;
2106
2107         /* Get a superblock - note that we may end up sharing one that already exists */
2108         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2109         if (IS_ERR(s)) {
2110                 error = PTR_ERR(s);
2111                 goto out_err_nosb;
2112         }
2113
2114         if (s->s_fs_info != server) {
2115                 nfs_free_server(server);
2116                 server = NULL;
2117         } else {
2118                 error = nfs_bdi_register(server);
2119                 if (error)
2120                         goto error_splat_super;
2121         }
2122
2123         if (!s->s_root) {
2124                 /* initial superblock/root creation */
2125                 nfs_clone_super(s, data->sb);
2126         }
2127
2128         mntroot = nfs_get_root(s, data->fh);
2129         if (IS_ERR(mntroot)) {
2130                 error = PTR_ERR(mntroot);
2131                 goto error_splat_super;
2132         }
2133         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2134                 dput(mntroot);
2135                 error = -ESTALE;
2136                 goto error_splat_super;
2137         }
2138
2139         s->s_flags |= MS_ACTIVE;
2140         mnt->mnt_sb = s;
2141         mnt->mnt_root = mntroot;
2142
2143         /* clone any lsm security options from the parent to the new sb */
2144         security_sb_clone_mnt_opts(data->sb, s);
2145
2146         dprintk("<-- nfs_xdev_get_sb() = 0\n");
2147         return 0;
2148
2149 out_err_nosb:
2150         nfs_free_server(server);
2151 out_err_noserver:
2152         dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
2153         return error;
2154
2155 error_splat_super:
2156         up_write(&s->s_umount);
2157         deactivate_super(s);
2158         dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
2159         return error;
2160 }
2161
2162 #ifdef CONFIG_NFS_V4
2163
2164 /*
2165  * Finish setting up a cloned NFS4 superblock
2166  */
2167 static void nfs4_clone_super(struct super_block *sb,
2168                             const struct super_block *old_sb)
2169 {
2170         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2171         sb->s_blocksize = old_sb->s_blocksize;
2172         sb->s_maxbytes = old_sb->s_maxbytes;
2173         sb->s_time_gran = 1;
2174         sb->s_op = old_sb->s_op;
2175         nfs_initialise_sb(sb);
2176 }
2177
2178 /*
2179  * Set up an NFS4 superblock
2180  */
2181 static void nfs4_fill_super(struct super_block *sb)
2182 {
2183         sb->s_time_gran = 1;
2184         sb->s_op = &nfs4_sops;
2185         nfs_initialise_sb(sb);
2186 }
2187
2188 /*
2189  * Validate NFSv4 mount options
2190  */
2191 static int nfs4_validate_mount_data(void *options,
2192                                     struct nfs_parsed_mount_data *args,
2193                                     const char *dev_name)
2194 {
2195         struct sockaddr_in *ap;
2196         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2197         char *c;
2198
2199         if (data == NULL)
2200                 goto out_no_data;
2201
2202         args->rsize             = NFS_MAX_FILE_IO_SIZE;
2203         args->wsize             = NFS_MAX_FILE_IO_SIZE;
2204         args->acregmin          = NFS_DEF_ACREGMIN;
2205         args->acregmax          = NFS_DEF_ACREGMAX;
2206         args->acdirmin          = NFS_DEF_ACDIRMIN;
2207         args->acdirmax          = NFS_DEF_ACDIRMAX;
2208         args->nfs_server.port   = NFS_PORT; /* 2049 unless user set port= */
2209         args->auth_flavors[0]   = RPC_AUTH_UNIX;
2210         args->auth_flavor_len   = 0;
2211
2212         switch (data->version) {
2213         case 1:
2214                 ap = (struct sockaddr_in *)&args->nfs_server.address;
2215                 if (data->host_addrlen > sizeof(args->nfs_server.address))
2216                         goto out_no_address;
2217                 if (data->host_addrlen == 0)
2218                         goto out_no_address;
2219                 args->nfs_server.addrlen = data->host_addrlen;
2220                 if (copy_from_user(ap, data->host_addr, data->host_addrlen))
2221                         return -EFAULT;
2222                 if (!nfs_verify_server_address((struct sockaddr *)
2223                                                 &args->nfs_server.address))
2224                         goto out_no_address;
2225
2226                 if (data->auth_flavourlen) {
2227                         if (data->auth_flavourlen > 1)
2228                                 goto out_inval_auth;
2229                         if (copy_from_user(&args->auth_flavors[0],
2230                                            data->auth_flavours,
2231                                            sizeof(args->auth_flavors[0])))
2232                                 return -EFAULT;
2233                 }
2234
2235                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2236                 if (IS_ERR(c))
2237                         return PTR_ERR(c);
2238                 args->nfs_server.hostname = c;
2239
2240                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2241                 if (IS_ERR(c))
2242                         return PTR_ERR(c);
2243                 args->nfs_server.export_path = c;
2244                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2245
2246                 c = strndup_user(data->client_addr.data, 16);
2247                 if (IS_ERR(c))
2248                         return PTR_ERR(c);
2249                 args->client_address = c;
2250
2251                 /*
2252                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2253                  * can deal with.
2254                  */
2255
2256                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
2257                 args->rsize     = data->rsize;
2258                 args->wsize     = data->wsize;
2259                 args->timeo     = data->timeo;
2260                 args->retrans   = data->retrans;
2261                 args->acregmin  = data->acregmin;
2262                 args->acregmax  = data->acregmax;
2263                 args->acdirmin  = data->acdirmin;
2264                 args->acdirmax  = data->acdirmax;
2265                 args->nfs_server.protocol = data->proto;
2266                 nfs_validate_transport_protocol(args);
2267
2268                 break;
2269         default: {
2270                 int status;
2271
2272                 if (nfs_parse_mount_options((char *)options, args) == 0)
2273                         return -EINVAL;
2274
2275                 if (!nfs_verify_server_address((struct sockaddr *)
2276                                                 &args->nfs_server.address))
2277                         return -EINVAL;
2278
2279                 nfs_set_port((struct sockaddr *)&args->nfs_server.address,
2280                                 args->nfs_server.port);
2281
2282                 nfs_validate_transport_protocol(args);
2283
2284                 if (args->auth_flavor_len > 1)
2285                         goto out_inval_auth;
2286
2287                 if (args->client_address == NULL)
2288                         goto out_no_client_address;
2289
2290                 status = nfs_parse_devname(dev_name,
2291                                            &args->nfs_server.hostname,
2292                                            NFS4_MAXNAMLEN,
2293                                            &args->nfs_server.export_path,
2294                                            NFS4_MAXPATHLEN);
2295                 if (status < 0)
2296                         return status;
2297
2298                 break;
2299                 }
2300         }
2301
2302         return 0;
2303
2304 out_no_data:
2305         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2306         return -EINVAL;
2307
2308 out_inval_auth:
2309         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2310                  data->auth_flavourlen);
2311         return -EINVAL;
2312
2313 out_no_address:
2314         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2315         return -EINVAL;
2316
2317 out_no_client_address:
2318         dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
2319         return -EINVAL;
2320 }
2321
2322 /*
2323  * Get the superblock for an NFS4 mountpoint
2324  */
2325 static int nfs4_get_sb(struct file_system_type *fs_type,
2326         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2327 {
2328         struct nfs_parsed_mount_data *data;
2329         struct super_block *s;
2330         struct nfs_server *server;
2331         struct nfs_fh *mntfh;
2332         struct dentry *mntroot;
2333         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2334         struct nfs_sb_mountdata sb_mntdata = {
2335                 .mntflags = flags,
2336         };
2337         int error = -ENOMEM;
2338
2339         data = kzalloc(sizeof(*data), GFP_KERNEL);
2340         mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
2341         if (data == NULL || mntfh == NULL)
2342                 goto out_free_fh;
2343
2344         security_init_mnt_opts(&data->lsm_opts);
2345
2346         /* Validate the mount data */
2347         error = nfs4_validate_mount_data(raw_data, data, dev_name);
2348         if (error < 0)
2349                 goto out;
2350
2351         /* Get a volume representation */
2352         server = nfs4_create_server(data, mntfh);
2353         if (IS_ERR(server)) {
2354                 error = PTR_ERR(server);
2355                 goto out;
2356         }
2357         sb_mntdata.server = server;
2358
2359         if (server->flags & NFS4_MOUNT_UNSHARED)
2360                 compare_super = NULL;
2361
2362         /* Get a superblock - note that we may end up sharing one that already exists */
2363         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2364         if (IS_ERR(s)) {
2365                 error = PTR_ERR(s);
2366                 goto out_free;
2367         }
2368
2369         if (s->s_fs_info != server) {
2370                 nfs_free_server(server);
2371                 server = NULL;
2372         } else {
2373                 error = nfs_bdi_register(server);
2374                 if (error)
2375                         goto error_splat_super;
2376         }
2377
2378         if (!s->s_root) {
2379                 /* initial superblock/root creation */
2380                 nfs4_fill_super(s);
2381         }
2382
2383         mntroot = nfs4_get_root(s, mntfh);
2384         if (IS_ERR(mntroot)) {
2385                 error = PTR_ERR(mntroot);
2386                 goto error_splat_super;
2387         }
2388
2389         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2390         if (error)
2391                 goto error_splat_root;
2392
2393         s->s_flags |= MS_ACTIVE;
2394         mnt->mnt_sb = s;
2395         mnt->mnt_root = mntroot;
2396         error = 0;
2397
2398 out:
2399         kfree(data->client_address);
2400         kfree(data->nfs_server.export_path);
2401         kfree(data->nfs_server.hostname);
2402         security_free_mnt_opts(&data->lsm_opts);
2403 out_free_fh:
2404         kfree(mntfh);
2405         kfree(data);
2406         return error;
2407
2408 out_free:
2409         nfs_free_server(server);
2410         goto out;
2411
2412 error_splat_root:
2413         dput(mntroot);
2414 error_splat_super:
2415         up_write(&s->s_umount);
2416         deactivate_super(s);
2417         goto out;
2418 }
2419
2420 static void nfs4_kill_super(struct super_block *sb)
2421 {
2422         struct nfs_server *server = NFS_SB(sb);
2423
2424         nfs_return_all_delegations(sb);
2425         kill_anon_super(sb);
2426
2427         nfs4_renewd_prepare_shutdown(server);
2428         nfs_free_server(server);
2429 }
2430
2431 /*
2432  * Clone an NFS4 server record on xdev traversal (FSID-change)
2433  */
2434 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
2435                             const char *dev_name, void *raw_data,
2436                             struct vfsmount *mnt)
2437 {
2438         struct nfs_clone_mount *data = raw_data;
2439         struct super_block *s;
2440         struct nfs_server *server;
2441         struct dentry *mntroot;
2442         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2443         struct nfs_sb_mountdata sb_mntdata = {
2444                 .mntflags = flags,
2445         };
2446         int error;
2447
2448         dprintk("--> nfs4_xdev_get_sb()\n");
2449
2450         /* create a new volume representation */
2451         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2452         if (IS_ERR(server)) {
2453                 error = PTR_ERR(server);
2454                 goto out_err_noserver;
2455         }
2456         sb_mntdata.server = server;
2457
2458         if (server->flags & NFS4_MOUNT_UNSHARED)
2459                 compare_super = NULL;
2460
2461         /* Get a superblock - note that we may end up sharing one that already exists */
2462         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2463         if (IS_ERR(s)) {
2464                 error = PTR_ERR(s);
2465                 goto out_err_nosb;
2466         }
2467
2468         if (s->s_fs_info != server) {
2469                 nfs_free_server(server);
2470                 server = NULL;
2471         } else {
2472                 error = nfs_bdi_register(server);
2473                 if (error)
2474                         goto error_splat_super;
2475         }
2476
2477         if (!s->s_root) {
2478                 /* initial superblock/root creation */
2479                 nfs4_clone_super(s, data->sb);
2480         }
2481
2482         mntroot = nfs4_get_root(s, data->fh);
2483         if (IS_ERR(mntroot)) {
2484                 error = PTR_ERR(mntroot);
2485                 goto error_splat_super;
2486         }
2487         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2488                 dput(mntroot);
2489                 error = -ESTALE;
2490                 goto error_splat_super;
2491         }
2492
2493         s->s_flags |= MS_ACTIVE;
2494         mnt->mnt_sb = s;
2495         mnt->mnt_root = mntroot;
2496
2497         security_sb_clone_mnt_opts(data->sb, s);
2498
2499         dprintk("<-- nfs4_xdev_get_sb() = 0\n");
2500         return 0;
2501
2502 out_err_nosb:
2503         nfs_free_server(server);
2504 out_err_noserver:
2505         dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
2506         return error;
2507
2508 error_splat_super:
2509         up_write(&s->s_umount);
2510         deactivate_super(s);
2511         dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
2512         return error;
2513 }
2514
2515 /*
2516  * Create an NFS4 server record on referral traversal
2517  */
2518 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
2519                                 const char *dev_name, void *raw_data,
2520                                 struct vfsmount *mnt)
2521 {
2522         struct nfs_clone_mount *data = raw_data;
2523         struct super_block *s;
2524         struct nfs_server *server;
2525         struct dentry *mntroot;
2526         struct nfs_fh mntfh;
2527         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2528         struct nfs_sb_mountdata sb_mntdata = {
2529                 .mntflags = flags,
2530         };
2531         int error;
2532
2533         dprintk("--> nfs4_referral_get_sb()\n");
2534
2535         /* create a new volume representation */
2536         server = nfs4_create_referral_server(data, &mntfh);
2537         if (IS_ERR(server)) {
2538                 error = PTR_ERR(server);
2539                 goto out_err_noserver;
2540         }
2541         sb_mntdata.server = server;
2542
2543         if (server->flags & NFS4_MOUNT_UNSHARED)
2544                 compare_super = NULL;
2545
2546         /* Get a superblock - note that we may end up sharing one that already exists */
2547         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2548         if (IS_ERR(s)) {
2549                 error = PTR_ERR(s);
2550                 goto out_err_nosb;
2551         }
2552
2553         if (s->s_fs_info != server) {
2554                 nfs_free_server(server);
2555                 server = NULL;
2556         } else {
2557                 error = nfs_bdi_register(server);
2558                 if (error)
2559                         goto error_splat_super;
2560         }
2561
2562         if (!s->s_root) {
2563                 /* initial superblock/root creation */
2564                 nfs4_fill_super(s);
2565         }
2566
2567         mntroot = nfs4_get_root(s, &mntfh);
2568         if (IS_ERR(mntroot)) {
2569                 error = PTR_ERR(mntroot);
2570                 goto error_splat_super;
2571         }
2572         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2573                 dput(mntroot);
2574                 error = -ESTALE;
2575                 goto error_splat_super;
2576         }
2577
2578         s->s_flags |= MS_ACTIVE;
2579         mnt->mnt_sb = s;
2580         mnt->mnt_root = mntroot;
2581
2582         security_sb_clone_mnt_opts(data->sb, s);
2583
2584         dprintk("<-- nfs4_referral_get_sb() = 0\n");
2585         return 0;
2586
2587 out_err_nosb:
2588         nfs_free_server(server);
2589 out_err_noserver:
2590         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
2591         return error;
2592
2593 error_splat_super:
2594         up_write(&s->s_umount);
2595         deactivate_super(s);
2596         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
2597         return error;
2598 }
2599
2600 #endif /* CONFIG_NFS_V4 */