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