fs/nfs/super.c

   1 /*
   2  *  linux/fs/nfs/super.c
   3  *
   4  *  Copyright (C) 1992  Rick Sladkey
   5  *
   6  *  nfs superblock handling functions
   7  *
   8  *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
   9  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
  10  *
  11  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
  12  *  J.S.Peatfield@damtp.cam.ac.uk
  13  *
  14  *  Split from inode.c by David Howells <dhowells@redhat.com>
  15  *
  16  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
  17  *   particular server are held in the same superblock
  18  * - NFS superblocks can have several effective roots to the dentry tree
  19  * - directory type roots are spliced into the tree when a path from one root reaches the root
  20  *   of another (see nfs_lookup())
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25
  26 #include <linux/time.h>
  27 #include <linux/kernel.h>
  28 #include <linux/mm.h>
  29 #include <linux/string.h>
  30 #include <linux/stat.h>
  31 #include <linux/errno.h>
  32 #include <linux/unistd.h>
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/stats.h>
  35 #include <linux/sunrpc/metrics.h>
  36 #include <linux/sunrpc/xprtsock.h>
  37 #include <linux/sunrpc/xprtrdma.h>
  38 #include <linux/nfs_fs.h>
  39 #include <linux/nfs_mount.h>
  40 #include <linux/nfs4_mount.h>
  41 #include <linux/lockd/bind.h>
  42 #include <linux/seq_file.h>
  43 #include <linux/mount.h>
  44 #include <linux/mnt_namespace.h>
  45 #include <linux/namei.h>
  46 #include <linux/nfs_idmap.h>
  47 #include <linux/vfs.h>
  48 #include <linux/inet.h>
  49 #include <linux/in6.h>
  50 #include <linux/slab.h>
  51 #include <net/ipv6.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/nfs_xdr.h>
  54 #include <linux/magic.h>
  55 #include <linux/parser.h>
  56
  57 #include <asm/system.h>
  58 #include <asm/uaccess.h>
  59
  60 #include "nfs4_fs.h"
  61 #include "callback.h"
  62 #include "delegation.h"
  63 #include "iostat.h"
  64 #include "internal.h"
  65 #include "fscache.h"
  66
  67 #define NFSDBG_FACILITY         NFSDBG_VFS
  68
  69 #ifdef CONFIG_NFS_V3
  70 #define NFS_DEFAULT_VERSION 3
  71 #else
  72 #define NFS_DEFAULT_VERSION 2
  73 #endif
  74
  75 enum {
  76         /* Mount options that take no arguments */
  77         Opt_soft, Opt_hard,
  78         Opt_posix, Opt_noposix,
  79         Opt_cto, Opt_nocto,
  80         Opt_ac, Opt_noac,
  81         Opt_lock, Opt_nolock,
  82         Opt_v2, Opt_v3, Opt_v4,
  83         Opt_udp, Opt_tcp, Opt_rdma,
  84         Opt_acl, Opt_noacl,
  85         Opt_rdirplus, Opt_nordirplus,
  86         Opt_sharecache, Opt_nosharecache,
  87         Opt_resvport, Opt_noresvport,
  88         Opt_fscache, Opt_nofscache,
  89
  90         /* Mount options that take integer arguments */
  91         Opt_port,
  92         Opt_rsize, Opt_wsize, Opt_bsize,
  93         Opt_timeo, Opt_retrans,
  94         Opt_acregmin, Opt_acregmax,
  95         Opt_acdirmin, Opt_acdirmax,
  96         Opt_actimeo,
  97         Opt_namelen,
  98         Opt_mountport,
  99         Opt_mountvers,
 100         Opt_nfsvers,
 101         Opt_minorversion,
 102
 103         /* Mount options that take string arguments */
 104         Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
 105         Opt_addr, Opt_mountaddr, Opt_clientaddr,
 106         Opt_lookupcache,
 107         Opt_fscache_uniq,
 108         Opt_local_lock,
 109
 110         /* Special mount options */
 111         Opt_userspace, Opt_deprecated, Opt_sloppy,
 112
 113         Opt_err
 114 };
 115
 116 static const match_table_t nfs_mount_option_tokens = {
 117         { Opt_userspace, "bg" },
 118         { Opt_userspace, "fg" },
 119         { Opt_userspace, "retry=%s" },
 120
 121         { Opt_sloppy, "sloppy" },
 122
 123         { Opt_soft, "soft" },
 124         { Opt_hard, "hard" },
 125         { Opt_deprecated, "intr" },
 126         { Opt_deprecated, "nointr" },
 127         { Opt_posix, "posix" },
 128         { Opt_noposix, "noposix" },
 129         { Opt_cto, "cto" },
 130         { Opt_nocto, "nocto" },
 131         { Opt_ac, "ac" },
 132         { Opt_noac, "noac" },
 133         { Opt_lock, "lock" },
 134         { Opt_nolock, "nolock" },
 135         { Opt_v2, "v2" },
 136         { Opt_v3, "v3" },
 137         { Opt_v4, "v4" },
 138         { Opt_udp, "udp" },
 139         { Opt_tcp, "tcp" },
 140         { Opt_rdma, "rdma" },
 141         { Opt_acl, "acl" },
 142         { Opt_noacl, "noacl" },
 143         { Opt_rdirplus, "rdirplus" },
 144         { Opt_nordirplus, "nordirplus" },
 145         { Opt_sharecache, "sharecache" },
 146         { Opt_nosharecache, "nosharecache" },
 147         { Opt_resvport, "resvport" },
 148         { Opt_noresvport, "noresvport" },
 149         { Opt_fscache, "fsc" },
 150         { Opt_nofscache, "nofsc" },
 151
 152         { Opt_port, "port=%s" },
 153         { Opt_rsize, "rsize=%s" },
 154         { Opt_wsize, "wsize=%s" },
 155         { Opt_bsize, "bsize=%s" },
 156         { Opt_timeo, "timeo=%s" },
 157         { Opt_retrans, "retrans=%s" },
 158         { Opt_acregmin, "acregmin=%s" },
 159         { Opt_acregmax, "acregmax=%s" },
 160         { Opt_acdirmin, "acdirmin=%s" },
 161         { Opt_acdirmax, "acdirmax=%s" },
 162         { Opt_actimeo, "actimeo=%s" },
 163         { Opt_namelen, "namlen=%s" },
 164         { Opt_mountport, "mountport=%s" },
 165         { Opt_mountvers, "mountvers=%s" },
 166         { Opt_nfsvers, "nfsvers=%s" },
 167         { Opt_nfsvers, "vers=%s" },
 168         { Opt_minorversion, "minorversion=%s" },
 169
 170         { Opt_sec, "sec=%s" },
 171         { Opt_proto, "proto=%s" },
 172         { Opt_mountproto, "mountproto=%s" },
 173         { Opt_addr, "addr=%s" },
 174         { Opt_clientaddr, "clientaddr=%s" },
 175         { Opt_mounthost, "mounthost=%s" },
 176         { Opt_mountaddr, "mountaddr=%s" },
 177
 178         { Opt_lookupcache, "lookupcache=%s" },
 179         { Opt_fscache_uniq, "fsc=%s" },
 180         { Opt_local_lock, "local_lock=%s" },
 181
 182         { Opt_err, NULL }
 183 };
 184
 185 enum {
 186         Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
 187
 188         Opt_xprt_err
 189 };
 190
 191 static const match_table_t nfs_xprt_protocol_tokens = {
 192         { Opt_xprt_udp, "udp" },
 193         { Opt_xprt_udp6, "udp6" },
 194         { Opt_xprt_tcp, "tcp" },
 195         { Opt_xprt_tcp6, "tcp6" },
 196         { Opt_xprt_rdma, "rdma" },
 197
 198         { Opt_xprt_err, NULL }
 199 };
 200
 201 enum {
 202         Opt_sec_none, Opt_sec_sys,
 203         Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
 204         Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
 205         Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
 206
 207         Opt_sec_err
 208 };
 209
 210 static const match_table_t nfs_secflavor_tokens = {
 211         { Opt_sec_none, "none" },
 212         { Opt_sec_none, "null" },
 213         { Opt_sec_sys, "sys" },
 214
 215         { Opt_sec_krb5, "krb5" },
 216         { Opt_sec_krb5i, "krb5i" },
 217         { Opt_sec_krb5p, "krb5p" },
 218
 219         { Opt_sec_lkey, "lkey" },
 220         { Opt_sec_lkeyi, "lkeyi" },
 221         { Opt_sec_lkeyp, "lkeyp" },
 222
 223         { Opt_sec_spkm, "spkm3" },
 224         { Opt_sec_spkmi, "spkm3i" },
 225         { Opt_sec_spkmp, "spkm3p" },
 226
 227         { Opt_sec_err, NULL }
 228 };
 229
 230 enum {
 231         Opt_lookupcache_all, Opt_lookupcache_positive,
 232         Opt_lookupcache_none,
 233
 234         Opt_lookupcache_err
 235 };
 236
 237 static match_table_t nfs_lookupcache_tokens = {
 238         { Opt_lookupcache_all, "all" },
 239         { Opt_lookupcache_positive, "pos" },
 240         { Opt_lookupcache_positive, "positive" },
 241         { Opt_lookupcache_none, "none" },
 242
 243         { Opt_lookupcache_err, NULL }
 244 };
 245
 246 enum {
 247         Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_posix,
 248         Opt_local_lock_none,
 249
 250         Opt_local_lock_err
 251 };
 252
 253 static match_table_t nfs_local_lock_tokens = {
 254         { Opt_local_lock_all, "all" },
 255         { Opt_local_lock_flock, "flock" },
 256         { Opt_local_lock_posix, "posix" },
 257         { Opt_local_lock_none, "none" },
 258
 259         { Opt_local_lock_err, NULL }
 260 };
 261
 262
 263 static void nfs_umount_begin(struct super_block *);
 264 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 265 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 266 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
 267 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
 268 static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
 269                 int flags, const char *dev_name, void *raw_data);
 270 static void nfs_put_super(struct super_block *);
 271 static void nfs_kill_super(struct super_block *);
 272 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
 273
 274 static struct file_system_type nfs_fs_type = {
 275         .owner          = THIS_MODULE,
 276         .name           = "nfs",
 277         .get_sb         = nfs_get_sb,
 278         .kill_sb        = nfs_kill_super,
 279         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 280 };
 281
 282 struct file_system_type nfs_xdev_fs_type = {
 283         .owner          = THIS_MODULE,
 284         .name           = "nfs",
 285         .mount          = nfs_xdev_mount,
 286         .kill_sb        = nfs_kill_super,
 287         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 288 };
 289
 290 static const struct super_operations nfs_sops = {
 291         .alloc_inode    = nfs_alloc_inode,
 292         .destroy_inode  = nfs_destroy_inode,
 293         .write_inode    = nfs_write_inode,
 294         .put_super      = nfs_put_super,
 295         .statfs         = nfs_statfs,
 296         .evict_inode    = nfs_evict_inode,
 297         .umount_begin   = nfs_umount_begin,
 298         .show_options   = nfs_show_options,
 299         .show_stats     = nfs_show_stats,
 300         .remount_fs     = nfs_remount,
 301 };
 302
 303 #ifdef CONFIG_NFS_V4
 304 static int nfs4_validate_text_mount_data(void *options,
 305         struct nfs_parsed_mount_data *args, const char *dev_name);
 306 static int nfs4_try_mount(int flags, const char *dev_name,
 307         struct nfs_parsed_mount_data *data, struct vfsmount *mnt);
 308 static int nfs4_get_sb(struct file_system_type *fs_type,
 309         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 310 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
 311         int flags, const char *dev_name, void *raw_data);
 312 static struct dentry *nfs4_xdev_mount(struct file_system_type *fs_type,
 313         int flags, const char *dev_name, void *raw_data);
 314 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 315         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 316 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
 317         int flags, const char *dev_name, void *raw_data);
 318 static void nfs4_kill_super(struct super_block *sb);
 319
 320 static struct file_system_type nfs4_fs_type = {
 321         .owner          = THIS_MODULE,
 322         .name           = "nfs4",
 323         .get_sb         = nfs4_get_sb,
 324         .kill_sb        = nfs4_kill_super,
 325         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 326 };
 327
 328 static struct file_system_type nfs4_remote_fs_type = {
 329         .owner          = THIS_MODULE,
 330         .name           = "nfs4",
 331         .mount          = nfs4_remote_mount,
 332         .kill_sb        = nfs4_kill_super,
 333         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 334 };
 335
 336 struct file_system_type nfs4_xdev_fs_type = {
 337         .owner          = THIS_MODULE,
 338         .name           = "nfs4",
 339         .mount          = nfs4_xdev_mount,
 340         .kill_sb        = nfs4_kill_super,
 341         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 342 };
 343
 344 static struct file_system_type nfs4_remote_referral_fs_type = {
 345         .owner          = THIS_MODULE,
 346         .name           = "nfs4",
 347         .mount          = nfs4_remote_referral_mount,
 348         .kill_sb        = nfs4_kill_super,
 349         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 350 };
 351
 352 struct file_system_type nfs4_referral_fs_type = {
 353         .owner          = THIS_MODULE,
 354         .name           = "nfs4",
 355         .get_sb         = nfs4_referral_get_sb,
 356         .kill_sb        = nfs4_kill_super,
 357         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 358 };
 359
 360 static const struct super_operations nfs4_sops = {
 361         .alloc_inode    = nfs_alloc_inode,
 362         .destroy_inode  = nfs_destroy_inode,
 363         .write_inode    = nfs_write_inode,
 364         .put_super      = nfs_put_super,
 365         .statfs         = nfs_statfs,
 366         .evict_inode    = nfs4_evict_inode,
 367         .umount_begin   = nfs_umount_begin,
 368         .show_options   = nfs_show_options,
 369         .show_stats     = nfs_show_stats,
 370         .remount_fs     = nfs_remount,
 371 };
 372 #endif
 373
 374 static struct shrinker acl_shrinker = {
 375         .shrink         = nfs_access_cache_shrinker,
 376         .seeks          = DEFAULT_SEEKS,
 377 };
 378
 379 /*
 380  * Register the NFS filesystems
 381  */
 382 int __init register_nfs_fs(void)
 383 {
 384         int ret;
 385
 386         ret = register_filesystem(&nfs_fs_type);
 387         if (ret < 0)
 388                 goto error_0;
 389
 390         ret = nfs_register_sysctl();
 391         if (ret < 0)
 392                 goto error_1;
 393 #ifdef CONFIG_NFS_V4
 394         ret = register_filesystem(&nfs4_fs_type);
 395         if (ret < 0)
 396                 goto error_2;
 397 #endif
 398         register_shrinker(&acl_shrinker);
 399         return 0;
 400
 401 #ifdef CONFIG_NFS_V4
 402 error_2:
 403         nfs_unregister_sysctl();
 404 #endif
 405 error_1:
 406         unregister_filesystem(&nfs_fs_type);
 407 error_0:
 408         return ret;
 409 }
 410
 411 /*
 412  * Unregister the NFS filesystems
 413  */
 414 void __exit unregister_nfs_fs(void)
 415 {
 416         unregister_shrinker(&acl_shrinker);
 417 #ifdef CONFIG_NFS_V4
 418         unregister_filesystem(&nfs4_fs_type);
 419 #endif
 420         nfs_unregister_sysctl();
 421         unregister_filesystem(&nfs_fs_type);
 422 }
 423
 424 void nfs_sb_active(struct super_block *sb)
 425 {
 426         struct nfs_server *server = NFS_SB(sb);
 427
 428         if (atomic_inc_return(&server->active) == 1)
 429                 atomic_inc(&sb->s_active);
 430 }
 431
 432 void nfs_sb_deactive(struct super_block *sb)
 433 {
 434         struct nfs_server *server = NFS_SB(sb);
 435
 436         if (atomic_dec_and_test(&server->active))
 437                 deactivate_super(sb);
 438 }
 439
 440 /*
 441  * Deliver file system statistics to userspace
 442  */
 443 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 444 {
 445         struct nfs_server *server = NFS_SB(dentry->d_sb);
 446         unsigned char blockbits;
 447         unsigned long blockres;
 448         struct nfs_fh *fh = NFS_FH(dentry->d_inode);
 449         struct nfs_fsstat res;
 450         int error = -ENOMEM;
 451
 452         res.fattr = nfs_alloc_fattr();
 453         if (res.fattr == NULL)
 454                 goto out_err;
 455
 456         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 457         if (unlikely(error == -ESTALE)) {
 458                 struct dentry *pd_dentry;
 459
 460                 pd_dentry = dget_parent(dentry);
 461                 if (pd_dentry != NULL) {
 462                         nfs_zap_caches(pd_dentry->d_inode);
 463                         dput(pd_dentry);
 464                 }
 465         }
 466         nfs_free_fattr(res.fattr);
 467         if (error < 0)
 468                 goto out_err;
 469
 470         buf->f_type = NFS_SUPER_MAGIC;
 471
 472         /*
 473          * Current versions of glibc do not correctly handle the
 474          * case where f_frsize != f_bsize.  Eventually we want to
 475          * report the value of wtmult in this field.
 476          */
 477         buf->f_frsize = dentry->d_sb->s_blocksize;
 478
 479         /*
 480          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 481          * are reported in units of f_frsize.  Linux hasn't had
 482          * an f_frsize field in its statfs struct until recently,
 483          * thus historically Linux's sys_statfs reports these
 484          * fields in units of f_bsize.
 485          */
 486         buf->f_bsize = dentry->d_sb->s_blocksize;
 487         blockbits = dentry->d_sb->s_blocksize_bits;
 488         blockres = (1 << blockbits) - 1;
 489         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 490         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 491         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 492
 493         buf->f_files = res.tfiles;
 494         buf->f_ffree = res.afiles;
 495
 496         buf->f_namelen = server->namelen;
 497
 498         return 0;
 499
 500  out_err:
 501         dprintk("%s: statfs error = %d\n", __func__, -error);
 502         return error;
 503 }
 504
 505 /*
 506  * Map the security flavour number to a name
 507  */
 508 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 509 {
 510         static const struct {
 511                 rpc_authflavor_t flavour;
 512                 const char *str;
 513         } sec_flavours[] = {
 514                 { RPC_AUTH_NULL, "null" },
 515                 { RPC_AUTH_UNIX, "sys" },
 516                 { RPC_AUTH_GSS_KRB5, "krb5" },
 517                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 518                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 519                 { RPC_AUTH_GSS_LKEY, "lkey" },
 520                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 521                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 522                 { RPC_AUTH_GSS_SPKM, "spkm" },
 523                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 524                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 525                 { UINT_MAX, "unknown" }
 526         };
 527         int i;
 528
 529         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 530                 if (sec_flavours[i].flavour == flavour)
 531                         break;
 532         }
 533         return sec_flavours[i].str;
 534 }
 535
 536 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
 537                                   int showdefaults)
 538 {
 539         struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
 540
 541         seq_printf(m, ",mountproto=");
 542         switch (sap->sa_family) {
 543         case AF_INET:
 544                 switch (nfss->mountd_protocol) {
 545                 case IPPROTO_UDP:
 546                         seq_printf(m, RPCBIND_NETID_UDP);
 547                         break;
 548                 case IPPROTO_TCP:
 549                         seq_printf(m, RPCBIND_NETID_TCP);
 550                         break;
 551                 default:
 552                         if (showdefaults)
 553                                 seq_printf(m, "auto");
 554                 }
 555                 break;
 556         case AF_INET6:
 557                 switch (nfss->mountd_protocol) {
 558                 case IPPROTO_UDP:
 559                         seq_printf(m, RPCBIND_NETID_UDP6);
 560                         break;
 561                 case IPPROTO_TCP:
 562                         seq_printf(m, RPCBIND_NETID_TCP6);
 563                         break;
 564                 default:
 565                         if (showdefaults)
 566                                 seq_printf(m, "auto");
 567                 }
 568                 break;
 569         default:
 570                 if (showdefaults)
 571                         seq_printf(m, "auto");
 572         }
 573 }
 574
 575 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
 576                                     int showdefaults)
 577 {
 578         struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
 579
 580         if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
 581                 return;
 582
 583         switch (sap->sa_family) {
 584         case AF_INET: {
 585                 struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 586                 seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
 587                 break;
 588         }
 589         case AF_INET6: {
 590                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 591                 seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
 592                 break;
 593         }
 594         default:
 595                 if (showdefaults)
 596                         seq_printf(m, ",mountaddr=unspecified");
 597         }
 598
 599         if (nfss->mountd_version || showdefaults)
 600                 seq_printf(m, ",mountvers=%u", nfss->mountd_version);
 601         if (nfss->mountd_port || showdefaults)
 602                 seq_printf(m, ",mountport=%u", nfss->mountd_port);
 603
 604         nfs_show_mountd_netid(m, nfss, showdefaults);
 605 }
 606
 607 #ifdef CONFIG_NFS_V4
 608 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
 609                                     int showdefaults)
 610 {
 611         struct nfs_client *clp = nfss->nfs_client;
 612
 613         seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
 614         seq_printf(m, ",minorversion=%u", clp->cl_minorversion);
 615 }
 616 #else
 617 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
 618                                     int showdefaults)
 619 {
 620 }
 621 #endif
 622
 623 /*
 624  * Describe the mount options in force on this server representation
 625  */
 626 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
 627                                    int showdefaults)
 628 {
 629         static const struct proc_nfs_info {
 630                 int flag;
 631                 const char *str;
 632                 const char *nostr;
 633         } nfs_info[] = {
 634                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 635                 { NFS_MOUNT_POSIX, ",posix", "" },
 636                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 637                 { NFS_MOUNT_NOAC, ",noac", "" },
 638                 { NFS_MOUNT_NONLM, ",nolock", "" },
 639                 { NFS_MOUNT_NOACL, ",noacl", "" },
 640                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 641                 { NFS_MOUNT_UNSHARED, ",nosharecache", "" },
 642                 { NFS_MOUNT_NORESVPORT, ",noresvport", "" },
 643                 { 0, NULL, NULL }
 644         };
 645         const struct proc_nfs_info *nfs_infop;
 646         struct nfs_client *clp = nfss->nfs_client;
 647         u32 version = clp->rpc_ops->version;
 648         int local_flock, local_fcntl;
 649
 650         seq_printf(m, ",vers=%u", version);
 651         seq_printf(m, ",rsize=%u", nfss->rsize);
 652         seq_printf(m, ",wsize=%u", nfss->wsize);
 653         if (nfss->bsize != 0)
 654                 seq_printf(m, ",bsize=%u", nfss->bsize);
 655         seq_printf(m, ",namlen=%u", nfss->namelen);
 656         if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
 657                 seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
 658         if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
 659                 seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
 660         if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
 661                 seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
 662         if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
 663                 seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
 664         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 665                 if (nfss->flags & nfs_infop->flag)
 666                         seq_puts(m, nfs_infop->str);
 667                 else
 668                         seq_puts(m, nfs_infop->nostr);
 669         }
 670         seq_printf(m, ",proto=%s",
 671                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
 672         if (version == 4) {
 673                 if (nfss->port != NFS_PORT)
 674                         seq_printf(m, ",port=%u", nfss->port);
 675         } else
 676                 if (nfss->port)
 677                         seq_printf(m, ",port=%u", nfss->port);
 678
 679         seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
 680         seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
 681         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 682
 683         if (version != 4)
 684                 nfs_show_mountd_options(m, nfss, showdefaults);
 685         else
 686                 nfs_show_nfsv4_options(m, nfss, showdefaults);
 687
 688         if (nfss->options & NFS_OPTION_FSCACHE)
 689                 seq_printf(m, ",fsc");
 690
 691         if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
 692                 if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
 693                         seq_printf(m, ",lookupcache=none");
 694                 else
 695                         seq_printf(m, ",lookupcache=pos");
 696         }
 697
 698         local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
 699         local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
 700
 701         if (!local_flock && !local_fcntl)
 702                 seq_printf(m, ",local_lock=none");
 703         else if (local_flock && local_fcntl)
 704                 seq_printf(m, ",local_lock=all");
 705         else if (local_flock)
 706                 seq_printf(m, ",local_lock=flock");
 707         else
 708                 seq_printf(m, ",local_lock=posix");
 709 }
 710
 711 /*
 712  * Describe the mount options on this VFS mountpoint
 713  */
 714 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 715 {
 716         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 717
 718         nfs_show_mount_options(m, nfss, 0);
 719
 720         seq_printf(m, ",addr=%s",
 721                         rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
 722                                                         RPC_DISPLAY_ADDR));
 723
 724         return 0;
 725 }
 726
 727 /*
 728  * Present statistical information for this VFS mountpoint
 729  */
 730 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 731 {
 732         int i, cpu;
 733         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 734         struct rpc_auth *auth = nfss->client->cl_auth;
 735         struct nfs_iostats totals = { };
 736
 737         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 738
 739         /*
 740          * Display all mount option settings
 741          */
 742         seq_printf(m, "\n\topts:\t");
 743         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 744         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 745         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 746         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 747         nfs_show_mount_options(m, nfss, 1);
 748
 749         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 750
 751         seq_printf(m, "\n\tcaps:\t");
 752         seq_printf(m, "caps=0x%x", nfss->caps);
 753         seq_printf(m, ",wtmult=%u", nfss->wtmult);
 754         seq_printf(m, ",dtsize=%u", nfss->dtsize);
 755         seq_printf(m, ",bsize=%u", nfss->bsize);
 756         seq_printf(m, ",namlen=%u", nfss->namelen);
 757
 758 #ifdef CONFIG_NFS_V4
 759         if (nfss->nfs_client->rpc_ops->version == 4) {
 760                 seq_printf(m, "\n\tnfsv4:\t");
 761                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 762                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 763                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 764         }
 765 #endif
 766
 767         /*
 768          * Display security flavor in effect for this mount
 769          */
 770         seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
 771         if (auth->au_flavor)
 772                 seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
 773
 774         /*
 775          * Display superblock I/O counters
 776          */
 777         for_each_possible_cpu(cpu) {
 778                 struct nfs_iostats *stats;
 779
 780                 preempt_disable();
 781                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 782
 783                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 784                         totals.events[i] += stats->events[i];
 785                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 786                         totals.bytes[i] += stats->bytes[i];
 787 #ifdef CONFIG_NFS_FSCACHE
 788                 for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
 789                         totals.fscache[i] += stats->fscache[i];
 790 #endif
 791
 792                 preempt_enable();
 793         }
 794
 795         seq_printf(m, "\n\tevents:\t");
 796         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 797                 seq_printf(m, "%lu ", totals.events[i]);
 798         seq_printf(m, "\n\tbytes:\t");
 799         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 800                 seq_printf(m, "%Lu ", totals.bytes[i]);
 801 #ifdef CONFIG_NFS_FSCACHE
 802         if (nfss->options & NFS_OPTION_FSCACHE) {
 803                 seq_printf(m, "\n\tfsc:\t");
 804                 for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
 805                         seq_printf(m, "%Lu ", totals.bytes[i]);
 806         }
 807 #endif
 808         seq_printf(m, "\n");
 809
 810         rpc_print_iostats(m, nfss->client);
 811
 812         return 0;
 813 }
 814
 815 /*
 816  * Begin unmount by attempting to remove all automounted mountpoints we added
 817  * in response to xdev traversals and referrals
 818  */
 819 static void nfs_umount_begin(struct super_block *sb)
 820 {
 821         struct nfs_server *server;
 822         struct rpc_clnt *rpc;
 823
 824         server = NFS_SB(sb);
 825         /* -EIO all pending I/O */
 826         rpc = server->client_acl;
 827         if (!IS_ERR(rpc))
 828                 rpc_killall_tasks(rpc);
 829         rpc = server->client;
 830         if (!IS_ERR(rpc))
 831                 rpc_killall_tasks(rpc);
 832 }
 833
 834 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
 835 {
 836         struct nfs_parsed_mount_data *data;
 837
 838         data = kzalloc(sizeof(*data), GFP_KERNEL);
 839         if (data) {
 840                 data->acregmin          = NFS_DEF_ACREGMIN;
 841                 data->acregmax          = NFS_DEF_ACREGMAX;
 842                 data->acdirmin          = NFS_DEF_ACDIRMIN;
 843                 data->acdirmax          = NFS_DEF_ACDIRMAX;
 844                 data->mount_server.port = NFS_UNSPEC_PORT;
 845                 data->nfs_server.port   = NFS_UNSPEC_PORT;
 846                 data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 847                 data->auth_flavors[0]   = RPC_AUTH_UNIX;
 848                 data->auth_flavor_len   = 1;
 849                 data->version           = version;
 850                 data->minorversion      = 0;
 851         }
 852         return data;
 853 }
 854
 855 /*
 856  * Sanity-check a server address provided by the mount command.
 857  *
 858  * Address family must be initialized, and address must not be
 859  * the ANY address for that family.
 860  */
 861 static int nfs_verify_server_address(struct sockaddr *addr)
 862 {
 863         switch (addr->sa_family) {
 864         case AF_INET: {
 865                 struct sockaddr_in *sa = (struct sockaddr_in *)addr;
 866                 return sa->sin_addr.s_addr != htonl(INADDR_ANY);
 867         }
 868         case AF_INET6: {
 869                 struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
 870                 return !ipv6_addr_any(sa);
 871         }
 872         }
 873
 874         dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
 875         return 0;
 876 }
 877
 878 /*
 879  * Select between a default port value and a user-specified port value.
 880  * If a zero value is set, then autobind will be used.
 881  */
 882 static void nfs_set_port(struct sockaddr *sap, int *port,
 883                                  const unsigned short default_port)
 884 {
 885         if (*port == NFS_UNSPEC_PORT)
 886                 *port = default_port;
 887
 888         rpc_set_port(sap, *port);
 889 }
 890
 891 /*
 892  * Sanity check the NFS transport protocol.
 893  *
 894  */
 895 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
 896 {
 897         switch (mnt->nfs_server.protocol) {
 898         case XPRT_TRANSPORT_UDP:
 899         case XPRT_TRANSPORT_TCP:
 900         case XPRT_TRANSPORT_RDMA:
 901                 break;
 902         default:
 903                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 904         }
 905 }
 906
 907 /*
 908  * For text based NFSv2/v3 mounts, the mount protocol transport default
 909  * settings should depend upon the specified NFS transport.
 910  */
 911 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
 912 {
 913         nfs_validate_transport_protocol(mnt);
 914
 915         if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
 916             mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
 917                         return;
 918         switch (mnt->nfs_server.protocol) {
 919         case XPRT_TRANSPORT_UDP:
 920                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 921                 break;
 922         case XPRT_TRANSPORT_TCP:
 923         case XPRT_TRANSPORT_RDMA:
 924                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 925         }
 926 }
 927
 928 /*
 929  * Parse the value of the 'sec=' option.
 930  */
 931 static int nfs_parse_security_flavors(char *value,
 932                                       struct nfs_parsed_mount_data *mnt)
 933 {
 934         substring_t args[MAX_OPT_ARGS];
 935
 936         dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
 937
 938         switch (match_token(value, nfs_secflavor_tokens, args)) {
 939         case Opt_sec_none:
 940                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 941                 break;
 942         case Opt_sec_sys:
 943                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 944                 break;
 945         case Opt_sec_krb5:
 946                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 947                 break;
 948         case Opt_sec_krb5i:
 949                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 950                 break;
 951         case Opt_sec_krb5p:
 952                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 953                 break;
 954         case Opt_sec_lkey:
 955                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 956                 break;
 957         case Opt_sec_lkeyi:
 958                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 959                 break;
 960         case Opt_sec_lkeyp:
 961                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 962                 break;
 963         case Opt_sec_spkm:
 964                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 965                 break;
 966         case Opt_sec_spkmi:
 967                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 968                 break;
 969         case Opt_sec_spkmp:
 970                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 971                 break;
 972         default:
 973                 return 0;
 974         }
 975
 976         mnt->auth_flavor_len = 1;
 977         return 1;
 978 }
 979
 980 /*
 981  * Error-check and convert a string of mount options from user space into
 982  * a data structure.  The whole mount string is processed; bad options are
 983  * skipped as they are encountered.  If there were no errors, return 1;
 984  * otherwise return 0 (zero).
 985  */
 986 static int nfs_parse_mount_options(char *raw,
 987                                    struct nfs_parsed_mount_data *mnt)
 988 {
 989         char *p, *string, *secdata;
 990         int rc, sloppy = 0, invalid_option = 0;
 991         unsigned short protofamily = AF_UNSPEC;
 992         unsigned short mountfamily = AF_UNSPEC;
 993
 994         if (!raw) {
 995                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 996                 return 1;
 997         }
 998         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 999
1000         secdata = alloc_secdata();
1001         if (!secdata)
1002                 goto out_nomem;
1003
1004         rc = security_sb_copy_data(raw, secdata);
1005         if (rc)
1006                 goto out_security_failure;
1007
1008         rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1009         if (rc)
1010                 goto out_security_failure;
1011
1012         free_secdata(secdata);
1013
1014         while ((p = strsep(&raw, ",")) != NULL) {
1015                 substring_t args[MAX_OPT_ARGS];
1016                 unsigned long option;
1017                 int token;
1018
1019                 if (!*p)
1020                         continue;
1021
1022                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1023
1024                 token = match_token(p, nfs_mount_option_tokens, args);
1025                 switch (token) {
1026
1027                 /*
1028                  * boolean options:  foo/nofoo
1029                  */
1030                 case Opt_soft:
1031                         mnt->flags |= NFS_MOUNT_SOFT;
1032                         break;
1033                 case Opt_hard:
1034                         mnt->flags &= ~NFS_MOUNT_SOFT;
1035                         break;
1036                 case Opt_posix:
1037                         mnt->flags |= NFS_MOUNT_POSIX;
1038                         break;
1039                 case Opt_noposix:
1040                         mnt->flags &= ~NFS_MOUNT_POSIX;
1041                         break;
1042                 case Opt_cto:
1043                         mnt->flags &= ~NFS_MOUNT_NOCTO;
1044                         break;
1045                 case Opt_nocto:
1046                         mnt->flags |= NFS_MOUNT_NOCTO;
1047                         break;
1048                 case Opt_ac:
1049                         mnt->flags &= ~NFS_MOUNT_NOAC;
1050                         break;
1051                 case Opt_noac:
1052                         mnt->flags |= NFS_MOUNT_NOAC;
1053                         break;
1054                 case Opt_lock:
1055                         mnt->flags &= ~NFS_MOUNT_NONLM;
1056                         mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1057                                         NFS_MOUNT_LOCAL_FCNTL);
1058                         break;
1059                 case Opt_nolock:
1060                         mnt->flags |= NFS_MOUNT_NONLM;
1061                         mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1062                                        NFS_MOUNT_LOCAL_FCNTL);
1063                         break;
1064                 case Opt_v2:
1065                         mnt->flags &= ~NFS_MOUNT_VER3;
1066                         mnt->version = 2;
1067                         break;
1068                 case Opt_v3:
1069                         mnt->flags |= NFS_MOUNT_VER3;
1070                         mnt->version = 3;
1071                         break;
1072 #ifdef CONFIG_NFS_V4
1073                 case Opt_v4:
1074                         mnt->flags &= ~NFS_MOUNT_VER3;
1075                         mnt->version = 4;
1076                         break;
1077 #endif
1078                 case Opt_udp:
1079                         mnt->flags &= ~NFS_MOUNT_TCP;
1080                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1081                         break;
1082                 case Opt_tcp:
1083                         mnt->flags |= NFS_MOUNT_TCP;
1084                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1085                         break;
1086                 case Opt_rdma:
1087                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1088                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1089                         xprt_load_transport(p);
1090                         break;
1091                 case Opt_acl:
1092                         mnt->flags &= ~NFS_MOUNT_NOACL;
1093                         break;
1094                 case Opt_noacl:
1095                         mnt->flags |= NFS_MOUNT_NOACL;
1096                         break;
1097                 case Opt_rdirplus:
1098                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1099                         break;
1100                 case Opt_nordirplus:
1101                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1102                         break;
1103                 case Opt_sharecache:
1104                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
1105                         break;
1106                 case Opt_nosharecache:
1107                         mnt->flags |= NFS_MOUNT_UNSHARED;
1108                         break;
1109                 case Opt_resvport:
1110                         mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1111                         break;
1112                 case Opt_noresvport:
1113                         mnt->flags |= NFS_MOUNT_NORESVPORT;
1114                         break;
1115                 case Opt_fscache:
1116                         mnt->options |= NFS_OPTION_FSCACHE;
1117                         kfree(mnt->fscache_uniq);
1118                         mnt->fscache_uniq = NULL;
1119                         break;
1120                 case Opt_nofscache:
1121                         mnt->options &= ~NFS_OPTION_FSCACHE;
1122                         kfree(mnt->fscache_uniq);
1123                         mnt->fscache_uniq = NULL;
1124                         break;
1125
1126                 /*
1127                  * options that take numeric values
1128                  */
1129                 case Opt_port:
1130                         string = match_strdup(args);
1131                         if (string == NULL)
1132                                 goto out_nomem;
1133                         rc = strict_strtoul(string, 10, &option);
1134                         kfree(string);
1135                         if (rc != 0 || option > USHRT_MAX)
1136                                 goto out_invalid_value;
1137                         mnt->nfs_server.port = option;
1138                         break;
1139                 case Opt_rsize:
1140                         string = match_strdup(args);
1141                         if (string == NULL)
1142                                 goto out_nomem;
1143                         rc = strict_strtoul(string, 10, &option);
1144                         kfree(string);
1145                         if (rc != 0)
1146                                 goto out_invalid_value;
1147                         mnt->rsize = option;
1148                         break;
1149                 case Opt_wsize:
1150                         string = match_strdup(args);
1151                         if (string == NULL)
1152                                 goto out_nomem;
1153                         rc = strict_strtoul(string, 10, &option);
1154                         kfree(string);
1155                         if (rc != 0)
1156                                 goto out_invalid_value;
1157                         mnt->wsize = option;
1158                         break;
1159                 case Opt_bsize:
1160                         string = match_strdup(args);
1161                         if (string == NULL)
1162                                 goto out_nomem;
1163                         rc = strict_strtoul(string, 10, &option);
1164                         kfree(string);
1165                         if (rc != 0)
1166                                 goto out_invalid_value;
1167                         mnt->bsize = option;
1168                         break;
1169                 case Opt_timeo:
1170                         string = match_strdup(args);
1171                         if (string == NULL)
1172                                 goto out_nomem;
1173                         rc = strict_strtoul(string, 10, &option);
1174                         kfree(string);
1175                         if (rc != 0 || option == 0)
1176                                 goto out_invalid_value;
1177                         mnt->timeo = option;
1178                         break;
1179                 case Opt_retrans:
1180                         string = match_strdup(args);
1181                         if (string == NULL)
1182                                 goto out_nomem;
1183                         rc = strict_strtoul(string, 10, &option);
1184                         kfree(string);
1185                         if (rc != 0 || option == 0)
1186                                 goto out_invalid_value;
1187                         mnt->retrans = option;
1188                         break;
1189                 case Opt_acregmin:
1190                         string = match_strdup(args);
1191                         if (string == NULL)
1192                                 goto out_nomem;
1193                         rc = strict_strtoul(string, 10, &option);
1194                         kfree(string);
1195                         if (rc != 0)
1196                                 goto out_invalid_value;
1197                         mnt->acregmin = option;
1198                         break;
1199                 case Opt_acregmax:
1200                         string = match_strdup(args);
1201                         if (string == NULL)
1202                                 goto out_nomem;
1203                         rc = strict_strtoul(string, 10, &option);
1204                         kfree(string);
1205                         if (rc != 0)
1206                                 goto out_invalid_value;
1207                         mnt->acregmax = option;
1208                         break;
1209                 case Opt_acdirmin:
1210                         string = match_strdup(args);
1211                         if (string == NULL)
1212                                 goto out_nomem;
1213                         rc = strict_strtoul(string, 10, &option);
1214                         kfree(string);
1215                         if (rc != 0)
1216                                 goto out_invalid_value;
1217                         mnt->acdirmin = option;
1218                         break;
1219                 case Opt_acdirmax:
1220                         string = match_strdup(args);
1221                         if (string == NULL)
1222                                 goto out_nomem;
1223                         rc = strict_strtoul(string, 10, &option);
1224                         kfree(string);
1225                         if (rc != 0)
1226                                 goto out_invalid_value;
1227                         mnt->acdirmax = option;
1228                         break;
1229                 case Opt_actimeo:
1230                         string = match_strdup(args);
1231                         if (string == NULL)
1232                                 goto out_nomem;
1233                         rc = strict_strtoul(string, 10, &option);
1234                         kfree(string);
1235                         if (rc != 0)
1236                                 goto out_invalid_value;
1237                         mnt->acregmin = mnt->acregmax =
1238                         mnt->acdirmin = mnt->acdirmax = option;
1239                         break;
1240                 case Opt_namelen:
1241                         string = match_strdup(args);
1242                         if (string == NULL)
1243                                 goto out_nomem;
1244                         rc = strict_strtoul(string, 10, &option);
1245                         kfree(string);
1246                         if (rc != 0)
1247                                 goto out_invalid_value;
1248                         mnt->namlen = option;
1249                         break;
1250                 case Opt_mountport:
1251                         string = match_strdup(args);
1252                         if (string == NULL)
1253                                 goto out_nomem;
1254                         rc = strict_strtoul(string, 10, &option);
1255                         kfree(string);
1256                         if (rc != 0 || option > USHRT_MAX)
1257                                 goto out_invalid_value;
1258                         mnt->mount_server.port = option;
1259                         break;
1260                 case Opt_mountvers:
1261                         string = match_strdup(args);
1262                         if (string == NULL)
1263                                 goto out_nomem;
1264                         rc = strict_strtoul(string, 10, &option);
1265                         kfree(string);
1266                         if (rc != 0 ||
1267                             option < NFS_MNT_VERSION ||
1268                             option > NFS_MNT3_VERSION)
1269                                 goto out_invalid_value;
1270                         mnt->mount_server.version = option;
1271                         break;
1272                 case Opt_nfsvers:
1273                         string = match_strdup(args);
1274                         if (string == NULL)
1275                                 goto out_nomem;
1276                         rc = strict_strtoul(string, 10, &option);
1277                         kfree(string);
1278                         if (rc != 0)
1279                                 goto out_invalid_value;
1280                         switch (option) {
1281                         case NFS2_VERSION:
1282                                 mnt->flags &= ~NFS_MOUNT_VER3;
1283                                 mnt->version = 2;
1284                                 break;
1285                         case NFS3_VERSION:
1286                                 mnt->flags |= NFS_MOUNT_VER3;
1287                                 mnt->version = 3;
1288                                 break;
1289 #ifdef CONFIG_NFS_V4
1290                         case NFS4_VERSION:
1291                                 mnt->flags &= ~NFS_MOUNT_VER3;
1292                                 mnt->version = 4;
1293                                 break;
1294 #endif
1295                         default:
1296                                 goto out_invalid_value;
1297                         }
1298                         break;
1299                 case Opt_minorversion:
1300                         string = match_strdup(args);
1301                         if (string == NULL)
1302                                 goto out_nomem;
1303                         rc = strict_strtoul(string, 10, &option);
1304                         kfree(string);
1305                         if (rc != 0)
1306                                 goto out_invalid_value;
1307                         if (option > NFS4_MAX_MINOR_VERSION)
1308                                 goto out_invalid_value;
1309                         mnt->minorversion = option;
1310                         break;
1311
1312                 /*
1313                  * options that take text values
1314                  */
1315                 case Opt_sec:
1316                         string = match_strdup(args);
1317                         if (string == NULL)
1318                                 goto out_nomem;
1319                         rc = nfs_parse_security_flavors(string, mnt);
1320                         kfree(string);
1321                         if (!rc) {
1322                                 dfprintk(MOUNT, "NFS:   unrecognized "
1323                                                 "security flavor\n");
1324                                 return 0;
1325                         }
1326                         break;
1327                 case Opt_proto:
1328                         string = match_strdup(args);
1329                         if (string == NULL)
1330                                 goto out_nomem;
1331                         token = match_token(string,
1332                                             nfs_xprt_protocol_tokens, args);
1333
1334                         protofamily = AF_INET;
1335                         switch (token) {
1336                         case Opt_xprt_udp6:
1337                                 protofamily = AF_INET6;
1338                         case Opt_xprt_udp:
1339                                 mnt->flags &= ~NFS_MOUNT_TCP;
1340                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1341                                 kfree(string);
1342                                 break;
1343                         case Opt_xprt_tcp6:
1344                                 protofamily = AF_INET6;
1345                         case Opt_xprt_tcp:
1346                                 mnt->flags |= NFS_MOUNT_TCP;
1347                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1348                                 kfree(string);
1349                                 break;
1350                         case Opt_xprt_rdma:
1351                                 /* vector side protocols to TCP */
1352                                 mnt->flags |= NFS_MOUNT_TCP;
1353                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1354                                 xprt_load_transport(string);
1355                                 kfree(string);
1356                                 break;
1357                         default:
1358                                 dfprintk(MOUNT, "NFS:   unrecognized "
1359                                                 "transport protocol\n");
1360                                 kfree(string);
1361                                 return 0;
1362                         }
1363                         break;
1364                 case Opt_mountproto:
1365                         string = match_strdup(args);
1366                         if (string == NULL)
1367                                 goto out_nomem;
1368                         token = match_token(string,
1369                                             nfs_xprt_protocol_tokens, args);
1370                         kfree(string);
1371
1372                         mountfamily = AF_INET;
1373                         switch (token) {
1374                         case Opt_xprt_udp6:
1375                                 mountfamily = AF_INET6;
1376                         case Opt_xprt_udp:
1377                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1378                                 break;
1379                         case Opt_xprt_tcp6:
1380                                 mountfamily = AF_INET6;
1381                         case Opt_xprt_tcp:
1382                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1383                                 break;
1384                         case Opt_xprt_rdma: /* not used for side protocols */
1385                         default:
1386                                 dfprintk(MOUNT, "NFS:   unrecognized "
1387                                                 "transport protocol\n");
1388                                 return 0;
1389                         }
1390                         break;
1391                 case Opt_addr:
1392                         string = match_strdup(args);
1393                         if (string == NULL)
1394                                 goto out_nomem;
1395                         mnt->nfs_server.addrlen =
1396                                 rpc_pton(string, strlen(string),
1397                                         (struct sockaddr *)
1398                                         &mnt->nfs_server.address,
1399                                         sizeof(mnt->nfs_server.address));
1400                         kfree(string);
1401                         if (mnt->nfs_server.addrlen == 0)
1402                                 goto out_invalid_address;
1403                         break;
1404                 case Opt_clientaddr:
1405                         string = match_strdup(args);
1406                         if (string == NULL)
1407                                 goto out_nomem;
1408                         kfree(mnt->client_address);
1409                         mnt->client_address = string;
1410                         break;
1411                 case Opt_mounthost:
1412                         string = match_strdup(args);
1413                         if (string == NULL)
1414                                 goto out_nomem;
1415                         kfree(mnt->mount_server.hostname);
1416                         mnt->mount_server.hostname = string;
1417                         break;
1418                 case Opt_mountaddr:
1419                         string = match_strdup(args);
1420                         if (string == NULL)
1421                                 goto out_nomem;
1422                         mnt->mount_server.addrlen =
1423                                 rpc_pton(string, strlen(string),
1424                                         (struct sockaddr *)
1425                                         &mnt->mount_server.address,
1426                                         sizeof(mnt->mount_server.address));
1427                         kfree(string);
1428                         if (mnt->mount_server.addrlen == 0)
1429                                 goto out_invalid_address;
1430                         break;
1431                 case Opt_lookupcache:
1432                         string = match_strdup(args);
1433                         if (string == NULL)
1434                                 goto out_nomem;
1435                         token = match_token(string,
1436                                         nfs_lookupcache_tokens, args);
1437                         kfree(string);
1438                         switch (token) {
1439                                 case Opt_lookupcache_all:
1440                                         mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1441                                         break;
1442                                 case Opt_lookupcache_positive:
1443                                         mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1444                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1445                                         break;
1446                                 case Opt_lookupcache_none:
1447                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1448                                         break;
1449                                 default:
1450                                         dfprintk(MOUNT, "NFS:   invalid "
1451                                                         "lookupcache argument\n");
1452                                         return 0;
1453                         };
1454                         break;
1455                 case Opt_fscache_uniq:
1456                         string = match_strdup(args);
1457                         if (string == NULL)
1458                                 goto out_nomem;
1459                         kfree(mnt->fscache_uniq);
1460                         mnt->fscache_uniq = string;
1461                         mnt->options |= NFS_OPTION_FSCACHE;
1462                         break;
1463                 case Opt_local_lock:
1464                         string = match_strdup(args);
1465                         if (string == NULL)
1466                                 goto out_nomem;
1467                         token = match_token(string, nfs_local_lock_tokens,
1468                                         args);
1469                         kfree(string);
1470                         switch (token) {
1471                         case Opt_local_lock_all:
1472                                 mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1473                                                NFS_MOUNT_LOCAL_FCNTL);
1474                                 break;
1475                         case Opt_local_lock_flock:
1476                                 mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1477                                 break;
1478                         case Opt_local_lock_posix:
1479                                 mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1480                                 break;
1481                         case Opt_local_lock_none:
1482                                 mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1483                                                 NFS_MOUNT_LOCAL_FCNTL);
1484                                 break;
1485                         default:
1486                                 dfprintk(MOUNT, "NFS:   invalid "
1487                                                 "local_lock argument\n");
1488                                 return 0;
1489                         };
1490                         break;
1491
1492                 /*
1493                  * Special options
1494                  */
1495                 case Opt_sloppy:
1496                         sloppy = 1;
1497                         dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1498                         break;
1499                 case Opt_userspace:
1500                 case Opt_deprecated:
1501                         dfprintk(MOUNT, "NFS:   ignoring mount option "
1502                                         "'%s'\n", p);
1503                         break;
1504
1505                 default:
1506                         invalid_option = 1;
1507                         dfprintk(MOUNT, "NFS:   unrecognized mount option "
1508                                         "'%s'\n", p);
1509                 }
1510         }
1511
1512         if (!sloppy && invalid_option)
1513                 return 0;
1514
1515         /*
1516          * verify that any proto=/mountproto= options match the address
1517          * familiies in the addr=/mountaddr= options.
1518          */
1519         if (protofamily != AF_UNSPEC &&
1520             protofamily != mnt->nfs_server.address.ss_family)
1521                 goto out_proto_mismatch;
1522
1523         if (mountfamily != AF_UNSPEC) {
1524                 if (mnt->mount_server.addrlen) {
1525                         if (mountfamily != mnt->mount_server.address.ss_family)
1526                                 goto out_mountproto_mismatch;
1527                 } else {
1528                         if (mountfamily != mnt->nfs_server.address.ss_family)
1529                                 goto out_mountproto_mismatch;
1530                 }
1531         }
1532
1533         return 1;
1534
1535 out_mountproto_mismatch:
1536         printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1537                          "option\n");
1538         return 0;
1539 out_proto_mismatch:
1540         printk(KERN_INFO "NFS: server address does not match proto= option\n");
1541         return 0;
1542 out_invalid_address:
1543         printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1544         return 0;
1545 out_invalid_value:
1546         printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1547         return 0;
1548 out_nomem:
1549         printk(KERN_INFO "NFS: not enough memory to parse option\n");
1550         return 0;
1551 out_security_failure:
1552         free_secdata(secdata);
1553         printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1554         return 0;
1555 }
1556
1557 /*
1558  * Match the requested auth flavors with the list returned by
1559  * the server.  Returns zero and sets the mount's authentication
1560  * flavor on success; returns -EACCES if server does not support
1561  * the requested flavor.
1562  */
1563 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1564                              struct nfs_mount_request *request)
1565 {
1566         unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1567
1568         /*
1569          * Certain releases of Linux's mountd return an empty
1570          * flavor list.  To prevent behavioral regression with
1571          * these servers (ie. rejecting mounts that used to
1572          * succeed), revert to pre-2.6.32 behavior (no checking)
1573          * if the returned flavor list is empty.
1574          */
1575         if (server_authlist_len == 0)
1576                 return 0;
1577
1578         /*
1579          * We avoid sophisticated negotiating here, as there are
1580          * plenty of cases where we can get it wrong, providing
1581          * either too little or too much security.
1582          *
1583          * RFC 2623, section 2.7 suggests we SHOULD prefer the
1584          * flavor listed first.  However, some servers list
1585          * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1586          * preferred default, in args->auth_flavors[0] if user
1587          * didn't specify sec= mount option.
1588          */
1589         for (i = 0; i < args->auth_flavor_len; i++)
1590                 for (j = 0; j < server_authlist_len; j++)
1591                         if (args->auth_flavors[i] == request->auth_flavs[j]) {
1592                                 dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1593                                         request->auth_flavs[j]);
1594                                 args->auth_flavors[0] = request->auth_flavs[j];
1595                                 return 0;
1596                         }
1597
1598         dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1599         nfs_umount(request);
1600         return -EACCES;
1601 }
1602
1603 /*
1604  * Use the remote server's MOUNT service to request the NFS file handle
1605  * corresponding to the provided path.
1606  */
1607 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1608                          struct nfs_fh *root_fh)
1609 {
1610         rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1611         unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1612         struct nfs_mount_request request = {
1613                 .sap            = (struct sockaddr *)
1614                                                 &args->mount_server.address,
1615                 .dirpath        = args->nfs_server.export_path,
1616                 .protocol       = args->mount_server.protocol,
1617                 .fh             = root_fh,
1618                 .noresvport     = args->flags & NFS_MOUNT_NORESVPORT,
1619                 .auth_flav_len  = &server_authlist_len,
1620                 .auth_flavs     = server_authlist,
1621         };
1622         int status;
1623
1624         if (args->mount_server.version == 0) {
1625                 switch (args->version) {
1626                         default:
1627                                 args->mount_server.version = NFS_MNT3_VERSION;
1628                                 break;
1629                         case 2:
1630                                 args->mount_server.version = NFS_MNT_VERSION;
1631                 }
1632         }
1633         request.version = args->mount_server.version;
1634
1635         if (args->mount_server.hostname)
1636                 request.hostname = args->mount_server.hostname;
1637         else
1638                 request.hostname = args->nfs_server.hostname;
1639
1640         /*
1641          * Construct the mount server's address.
1642          */
1643         if (args->mount_server.address.ss_family == AF_UNSPEC) {
1644                 memcpy(request.sap, &args->nfs_server.address,
1645                        args->nfs_server.addrlen);
1646                 args->mount_server.addrlen = args->nfs_server.addrlen;
1647         }
1648         request.salen = args->mount_server.addrlen;
1649         nfs_set_port(request.sap, &args->mount_server.port, 0);
1650
1651         /*
1652          * Now ask the mount server to map our export path
1653          * to a file handle.
1654          */
1655         status = nfs_mount(&request);
1656         if (status != 0) {
1657                 dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1658                                 request.hostname, status);
1659                 return status;
1660         }
1661
1662         /*
1663          * MNTv1 (NFSv2) does not support auth flavor negotiation.
1664          */
1665         if (args->mount_server.version != NFS_MNT3_VERSION)
1666                 return 0;
1667         return nfs_walk_authlist(args, &request);
1668 }
1669
1670 static int nfs_parse_simple_hostname(const char *dev_name,
1671                                      char **hostname, size_t maxnamlen,
1672                                      char **export_path, size_t maxpathlen)
1673 {
1674         size_t len;
1675         char *colon, *comma;
1676
1677         colon = strchr(dev_name, ':');
1678         if (colon == NULL)
1679                 goto out_bad_devname;
1680
1681         len = colon - dev_name;
1682         if (len > maxnamlen)
1683                 goto out_hostname;
1684
1685         /* N.B. caller will free nfs_server.hostname in all cases */
1686         *hostname = kstrndup(dev_name, len, GFP_KERNEL);
1687         if (!*hostname)
1688                 goto out_nomem;
1689
1690         /* kill possible hostname list: not supported */
1691         comma = strchr(*hostname, ',');
1692         if (comma != NULL) {
1693                 if (comma == *hostname)
1694                         goto out_bad_devname;
1695                 *comma = '\0';
1696         }
1697
1698         colon++;
1699         len = strlen(colon);
1700         if (len > maxpathlen)
1701                 goto out_path;
1702         *export_path = kstrndup(colon, len, GFP_KERNEL);
1703         if (!*export_path)
1704                 goto out_nomem;
1705
1706         dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1707         return 0;
1708
1709 out_bad_devname:
1710         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1711         return -EINVAL;
1712
1713 out_nomem:
1714         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1715         return -ENOMEM;
1716
1717 out_hostname:
1718         dfprintk(MOUNT, "NFS: server hostname too long\n");
1719         return -ENAMETOOLONG;
1720
1721 out_path:
1722         dfprintk(MOUNT, "NFS: export pathname too long\n");
1723         return -ENAMETOOLONG;
1724 }
1725
1726 /*
1727  * Hostname has square brackets around it because it contains one or
1728  * more colons.  We look for the first closing square bracket, and a
1729  * colon must follow it.
1730  */
1731 static int nfs_parse_protected_hostname(const char *dev_name,
1732                                         char **hostname, size_t maxnamlen,
1733                                         char **export_path, size_t maxpathlen)
1734 {
1735         size_t len;
1736         char *start, *end;
1737
1738         start = (char *)(dev_name + 1);
1739
1740         end = strchr(start, ']');
1741         if (end == NULL)
1742                 goto out_bad_devname;
1743         if (*(end + 1) != ':')
1744                 goto out_bad_devname;
1745
1746         len = end - start;
1747         if (len > maxnamlen)
1748                 goto out_hostname;
1749
1750         /* N.B. caller will free nfs_server.hostname in all cases */
1751         *hostname = kstrndup(start, len, GFP_KERNEL);
1752         if (*hostname == NULL)
1753                 goto out_nomem;
1754
1755         end += 2;
1756         len = strlen(end);
1757         if (len > maxpathlen)
1758                 goto out_path;
1759         *export_path = kstrndup(end, len, GFP_KERNEL);
1760         if (!*export_path)
1761                 goto out_nomem;
1762
1763         return 0;
1764
1765 out_bad_devname:
1766         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1767         return -EINVAL;
1768
1769 out_nomem:
1770         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1771         return -ENOMEM;
1772
1773 out_hostname:
1774         dfprintk(MOUNT, "NFS: server hostname too long\n");
1775         return -ENAMETOOLONG;
1776
1777 out_path:
1778         dfprintk(MOUNT, "NFS: export pathname too long\n");
1779         return -ENAMETOOLONG;
1780 }
1781
1782 /*
1783  * Split "dev_name" into "hostname:export_path".
1784  *
1785  * The leftmost colon demarks the split between the server's hostname
1786  * and the export path.  If the hostname starts with a left square
1787  * bracket, then it may contain colons.
1788  *
1789  * Note: caller frees hostname and export path, even on error.
1790  */
1791 static int nfs_parse_devname(const char *dev_name,
1792                              char **hostname, size_t maxnamlen,
1793                              char **export_path, size_t maxpathlen)
1794 {
1795         if (*dev_name == '[')
1796                 return nfs_parse_protected_hostname(dev_name,
1797                                                     hostname, maxnamlen,
1798                                                     export_path, maxpathlen);
1799
1800         return nfs_parse_simple_hostname(dev_name,
1801                                          hostname, maxnamlen,
1802                                          export_path, maxpathlen);
1803 }
1804
1805 /*
1806  * Validate the NFS2/NFS3 mount data
1807  * - fills in the mount root filehandle
1808  *
1809  * For option strings, user space handles the following behaviors:
1810  *
1811  * + DNS: mapping server host name to IP address ("addr=" option)
1812  *
1813  * + failure mode: how to behave if a mount request can't be handled
1814  *   immediately ("fg/bg" option)
1815  *
1816  * + retry: how often to retry a mount request ("retry=" option)
1817  *
1818  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1819  *   mountproto=tcp after mountproto=udp, and so on
1820  */
1821 static int nfs_validate_mount_data(void *options,
1822                                    struct nfs_parsed_mount_data *args,
1823                                    struct nfs_fh *mntfh,
1824                                    const char *dev_name)
1825 {
1826         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1827         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1828
1829         if (data == NULL)
1830                 goto out_no_data;
1831
1832         switch (data->version) {
1833         case 1:
1834                 data->namlen = 0;
1835         case 2:
1836                 data->bsize = 0;
1837         case 3:
1838                 if (data->flags & NFS_MOUNT_VER3)
1839                         goto out_no_v3;
1840                 data->root.size = NFS2_FHSIZE;
1841                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1842         case 4:
1843                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1844                         goto out_no_sec;
1845         case 5:
1846                 memset(data->context, 0, sizeof(data->context));
1847         case 6:
1848                 if (data->flags & NFS_MOUNT_VER3) {
1849                         if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1850                                 goto out_invalid_fh;
1851                         mntfh->size = data->root.size;
1852                         args->version = 3;
1853                 } else {
1854                         mntfh->size = NFS2_FHSIZE;
1855                         args->version = 2;
1856                 }
1857
1858
1859                 memcpy(mntfh->data, data->root.data, mntfh->size);
1860                 if (mntfh->size < sizeof(mntfh->data))
1861                         memset(mntfh->data + mntfh->size, 0,
1862                                sizeof(mntfh->data) - mntfh->size);
1863
1864                 /*
1865                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1866                  * can deal with.
1867                  */
1868                 args->flags             = data->flags & NFS_MOUNT_FLAGMASK;
1869                 args->flags             |= NFS_MOUNT_LEGACY_INTERFACE;
1870                 args->rsize             = data->rsize;
1871                 args->wsize             = data->wsize;
1872                 args->timeo             = data->timeo;
1873                 args->retrans           = data->retrans;
1874                 args->acregmin          = data->acregmin;
1875                 args->acregmax          = data->acregmax;
1876                 args->acdirmin          = data->acdirmin;
1877                 args->acdirmax          = data->acdirmax;
1878
1879                 memcpy(sap, &data->addr, sizeof(data->addr));
1880                 args->nfs_server.addrlen = sizeof(data->addr);
1881                 if (!nfs_verify_server_address(sap))
1882                         goto out_no_address;
1883
1884                 if (!(data->flags & NFS_MOUNT_TCP))
1885                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1886                 /* N.B. caller will free nfs_server.hostname in all cases */
1887                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1888                 args->namlen            = data->namlen;
1889                 args->bsize             = data->bsize;
1890
1891                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1892                         args->auth_flavors[0] = data->pseudoflavor;
1893                 if (!args->nfs_server.hostname)
1894                         goto out_nomem;
1895
1896                 if (!(data->flags & NFS_MOUNT_NONLM))
1897                         args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1898                                          NFS_MOUNT_LOCAL_FCNTL);
1899                 else
1900                         args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1901                                         NFS_MOUNT_LOCAL_FCNTL);
1902                 /*
1903                  * The legacy version 6 binary mount data from userspace has a
1904                  * field used only to transport selinux information into the
1905                  * the kernel.  To continue to support that functionality we
1906                  * have a touch of selinux knowledge here in the NFS code. The
1907                  * userspace code converted context=blah to just blah so we are
1908                  * converting back to the full string selinux understands.
1909                  */
1910                 if (data->context[0]){
1911 #ifdef CONFIG_SECURITY_SELINUX
1912                         int rc;
1913                         char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1914                         if (!opts_str)
1915                                 return -ENOMEM;
1916                         strcpy(opts_str, "context=");
1917                         data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1918                         strcat(opts_str, &data->context[0]);
1919                         rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1920                         kfree(opts_str);
1921                         if (rc)
1922                                 return rc;
1923 #else
1924                         return -EINVAL;
1925 #endif
1926                 }
1927
1928                 break;
1929         default: {
1930                 int status;
1931
1932                 if (nfs_parse_mount_options((char *)options, args) == 0)
1933                         return -EINVAL;
1934
1935                 if (!nfs_verify_server_address(sap))
1936                         goto out_no_address;
1937
1938                 if (args->version == 4)
1939 #ifdef CONFIG_NFS_V4
1940                         return nfs4_validate_text_mount_data(options,
1941                                                              args, dev_name);
1942 #else
1943                         goto out_v4_not_compiled;
1944 #endif
1945
1946                 nfs_set_port(sap, &args->nfs_server.port, 0);
1947
1948                 nfs_set_mount_transport_protocol(args);
1949
1950                 status = nfs_parse_devname(dev_name,
1951                                            &args->nfs_server.hostname,
1952                                            PAGE_SIZE,
1953                                            &args->nfs_server.export_path,
1954                                            NFS_MAXPATHLEN);
1955                 if (!status)
1956                         status = nfs_try_mount(args, mntfh);
1957
1958                 kfree(args->nfs_server.export_path);
1959                 args->nfs_server.export_path = NULL;
1960
1961                 if (status)
1962                         return status;
1963
1964                 break;
1965                 }
1966         }
1967
1968 #ifndef CONFIG_NFS_V3
1969         if (args->version == 3)
1970                 goto out_v3_not_compiled;
1971 #endif /* !CONFIG_NFS_V3 */
1972
1973         return 0;
1974
1975 out_no_data:
1976         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1977         return -EINVAL;
1978
1979 out_no_v3:
1980         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1981                  data->version);
1982         return -EINVAL;
1983
1984 out_no_sec:
1985         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1986         return -EINVAL;
1987
1988 #ifndef CONFIG_NFS_V3
1989 out_v3_not_compiled:
1990         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1991         return -EPROTONOSUPPORT;
1992 #endif /* !CONFIG_NFS_V3 */
1993
1994 #ifndef CONFIG_NFS_V4
1995 out_v4_not_compiled:
1996         dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1997         return -EPROTONOSUPPORT;
1998 #endif /* !CONFIG_NFS_V4 */
1999
2000 out_nomem:
2001         dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
2002         return -ENOMEM;
2003
2004 out_no_address:
2005         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2006         return -EINVAL;
2007
2008 out_invalid_fh:
2009         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2010         return -EINVAL;
2011 }
2012
2013 static int
2014 nfs_compare_remount_data(struct nfs_server *nfss,
2015                          struct nfs_parsed_mount_data *data)
2016 {
2017         if (data->flags != nfss->flags ||
2018             data->rsize != nfss->rsize ||
2019             data->wsize != nfss->wsize ||
2020             data->retrans != nfss->client->cl_timeout->to_retries ||
2021             data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2022             data->acregmin != nfss->acregmin / HZ ||
2023             data->acregmax != nfss->acregmax / HZ ||
2024             data->acdirmin != nfss->acdirmin / HZ ||
2025             data->acdirmax != nfss->acdirmax / HZ ||
2026             data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2027             data->nfs_server.port != nfss->port ||
2028             data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2029             !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2030                           (struct sockaddr *)&nfss->nfs_client->cl_addr))
2031                 return -EINVAL;
2032
2033         return 0;
2034 }
2035
2036 static int
2037 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2038 {
2039         int error;
2040         struct nfs_server *nfss = sb->s_fs_info;
2041         struct nfs_parsed_mount_data *data;
2042         struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2043         struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2044         u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2045
2046         /*
2047          * Userspace mount programs that send binary options generally send
2048          * them populated with default values. We have no way to know which
2049          * ones were explicitly specified. Fall back to legacy behavior and
2050          * just return success.
2051          */
2052         if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2053             (nfsvers <= 3 && (!options || (options->version >= 1 &&
2054                                            options->version <= 6))))
2055                 return 0;
2056
2057         data = kzalloc(sizeof(*data), GFP_KERNEL);
2058         if (data == NULL)
2059                 return -ENOMEM;
2060
2061         /* fill out struct with values from existing mount */
2062         data->flags = nfss->flags;
2063         data->rsize = nfss->rsize;
2064         data->wsize = nfss->wsize;
2065         data->retrans = nfss->client->cl_timeout->to_retries;
2066         data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2067         data->acregmin = nfss->acregmin / HZ;
2068         data->acregmax = nfss->acregmax / HZ;
2069         data->acdirmin = nfss->acdirmin / HZ;
2070         data->acdirmax = nfss->acdirmax / HZ;
2071         data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2072         data->nfs_server.port = nfss->port;
2073         data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2074         memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2075                 data->nfs_server.addrlen);
2076
2077         /* overwrite those values with any that were specified */
2078         error = nfs_parse_mount_options((char *)options, data);
2079         if (error < 0)
2080                 goto out;
2081
2082         /* compare new mount options with old ones */
2083         error = nfs_compare_remount_data(nfss, data);
2084 out:
2085         kfree(data);
2086         return error;
2087 }
2088
2089 /*
2090  * Initialise the common bits of the superblock
2091  */
2092 static inline void nfs_initialise_sb(struct super_block *sb)
2093 {
2094         struct nfs_server *server = NFS_SB(sb);
2095
2096         sb->s_magic = NFS_SUPER_MAGIC;
2097
2098         /* We probably want something more informative here */
2099         snprintf(sb->s_id, sizeof(sb->s_id),
2100                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2101
2102         if (sb->s_blocksize == 0)
2103                 sb->s_blocksize = nfs_block_bits(server->wsize,
2104                                                  &sb->s_blocksize_bits);
2105
2106         if (server->flags & NFS_MOUNT_NOAC)
2107                 sb->s_flags |= MS_SYNCHRONOUS;
2108
2109         sb->s_bdi = &server->backing_dev_info;
2110
2111         nfs_super_set_maxbytes(sb, server->maxfilesize);
2112 }
2113
2114 /*
2115  * Finish setting up an NFS2/3 superblock
2116  */
2117 static void nfs_fill_super(struct super_block *sb,
2118                            struct nfs_parsed_mount_data *data)
2119 {
2120         struct nfs_server *server = NFS_SB(sb);
2121
2122         sb->s_blocksize_bits = 0;
2123         sb->s_blocksize = 0;
2124         if (data->bsize)
2125                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2126
2127         if (server->nfs_client->rpc_ops->version == 3) {
2128                 /* The VFS shouldn't apply the umask to mode bits. We will do
2129                  * so ourselves when necessary.
2130                  */
2131                 sb->s_flags |= MS_POSIXACL;
2132                 sb->s_time_gran = 1;
2133         }
2134
2135         sb->s_op = &nfs_sops;
2136         nfs_initialise_sb(sb);
2137 }
2138
2139 /*
2140  * Finish setting up a cloned NFS2/3 superblock
2141  */
2142 static void nfs_clone_super(struct super_block *sb,
2143                             const struct super_block *old_sb)
2144 {
2145         struct nfs_server *server = NFS_SB(sb);
2146
2147         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2148         sb->s_blocksize = old_sb->s_blocksize;
2149         sb->s_maxbytes = old_sb->s_maxbytes;
2150
2151         if (server->nfs_client->rpc_ops->version == 3) {
2152                 /* The VFS shouldn't apply the umask to mode bits. We will do
2153                  * so ourselves when necessary.
2154                  */
2155                 sb->s_flags |= MS_POSIXACL;
2156                 sb->s_time_gran = 1;
2157         }
2158
2159         sb->s_op = old_sb->s_op;
2160         nfs_initialise_sb(sb);
2161 }
2162
2163 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2164 {
2165         const struct nfs_server *a = s->s_fs_info;
2166         const struct rpc_clnt *clnt_a = a->client;
2167         const struct rpc_clnt *clnt_b = b->client;
2168
2169         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2170                 goto Ebusy;
2171         if (a->nfs_client != b->nfs_client)
2172                 goto Ebusy;
2173         if (a->flags != b->flags)
2174                 goto Ebusy;
2175         if (a->wsize != b->wsize)
2176                 goto Ebusy;
2177         if (a->rsize != b->rsize)
2178                 goto Ebusy;
2179         if (a->acregmin != b->acregmin)
2180                 goto Ebusy;
2181         if (a->acregmax != b->acregmax)
2182                 goto Ebusy;
2183         if (a->acdirmin != b->acdirmin)
2184                 goto Ebusy;
2185         if (a->acdirmax != b->acdirmax)
2186                 goto Ebusy;
2187         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2188                 goto Ebusy;
2189         return 1;
2190 Ebusy:
2191         return 0;
2192 }
2193
2194 struct nfs_sb_mountdata {
2195         struct nfs_server *server;
2196         int mntflags;
2197 };
2198
2199 static int nfs_set_super(struct super_block *s, void *data)
2200 {
2201         struct nfs_sb_mountdata *sb_mntdata = data;
2202         struct nfs_server *server = sb_mntdata->server;
2203         int ret;
2204
2205         s->s_flags = sb_mntdata->mntflags;
2206         s->s_fs_info = server;
2207         ret = set_anon_super(s, server);
2208         if (ret == 0)
2209                 server->s_dev = s->s_dev;
2210         return ret;
2211 }
2212
2213 static int nfs_compare_super_address(struct nfs_server *server1,
2214                                      struct nfs_server *server2)
2215 {
2216         struct sockaddr *sap1, *sap2;
2217
2218         sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2219         sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2220
2221         if (sap1->sa_family != sap2->sa_family)
2222                 return 0;
2223
2224         switch (sap1->sa_family) {
2225         case AF_INET: {
2226                 struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2227                 struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2228                 if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2229                         return 0;
2230                 if (sin1->sin_port != sin2->sin_port)
2231                         return 0;
2232                 break;
2233         }
2234         case AF_INET6: {
2235                 struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2236                 struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2237                 if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2238                         return 0;
2239                 if (sin1->sin6_port != sin2->sin6_port)
2240                         return 0;
2241                 break;
2242         }
2243         default:
2244                 return 0;
2245         }
2246
2247         return 1;
2248 }
2249
2250 static int nfs_compare_super(struct super_block *sb, void *data)
2251 {
2252         struct nfs_sb_mountdata *sb_mntdata = data;
2253         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2254         int mntflags = sb_mntdata->mntflags;
2255
2256         if (!nfs_compare_super_address(old, server))
2257                 return 0;
2258         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2259         if (old->flags & NFS_MOUNT_UNSHARED)
2260                 return 0;
2261         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2262                 return 0;
2263         return nfs_compare_mount_options(sb, server, mntflags);
2264 }
2265
2266 static int nfs_bdi_register(struct nfs_server *server)
2267 {
2268         return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2269 }
2270
2271 static int nfs_get_sb(struct file_system_type *fs_type,
2272         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2273 {
2274         struct nfs_server *server = NULL;
2275         struct super_block *s;
2276         struct nfs_parsed_mount_data *data;
2277         struct nfs_fh *mntfh;
2278         struct dentry *mntroot;
2279         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2280         struct nfs_sb_mountdata sb_mntdata = {
2281                 .mntflags = flags,
2282         };
2283         int error = -ENOMEM;
2284
2285         data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
2286         mntfh = nfs_alloc_fhandle();
2287         if (data == NULL || mntfh == NULL)
2288                 goto out_free_fh;
2289
2290         security_init_mnt_opts(&data->lsm_opts);
2291
2292         /* Validate the mount data */
2293         error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2294         if (error < 0)
2295                 goto out;
2296
2297 #ifdef CONFIG_NFS_V4
2298         if (data->version == 4) {
2299                 error = nfs4_try_mount(flags, dev_name, data, mnt);
2300                 kfree(data->client_address);
2301                 kfree(data->nfs_server.export_path);
2302                 goto out;
2303         }
2304 #endif  /* CONFIG_NFS_V4 */
2305
2306         /* Get a volume representation */
2307         server = nfs_create_server(data, mntfh);
2308         if (IS_ERR(server)) {
2309                 error = PTR_ERR(server);
2310                 goto out;
2311         }
2312         sb_mntdata.server = server;
2313
2314         if (server->flags & NFS_MOUNT_UNSHARED)
2315                 compare_super = NULL;
2316
2317         /* Get a superblock - note that we may end up sharing one that already exists */
2318         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2319         if (IS_ERR(s)) {
2320                 error = PTR_ERR(s);
2321                 goto out_err_nosb;
2322         }
2323
2324         if (s->s_fs_info != server) {
2325                 nfs_free_server(server);
2326                 server = NULL;
2327         } else {
2328                 error = nfs_bdi_register(server);
2329                 if (error)
2330                         goto error_splat_bdi;
2331         }
2332
2333         if (!s->s_root) {
2334                 /* initial superblock/root creation */
2335                 nfs_fill_super(s, data);
2336                 nfs_fscache_get_super_cookie(
2337                         s, data ? data->fscache_uniq : NULL, NULL);
2338         }
2339
2340         mntroot = nfs_get_root(s, mntfh);
2341         if (IS_ERR(mntroot)) {
2342                 error = PTR_ERR(mntroot);
2343                 goto error_splat_super;
2344         }
2345
2346         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2347         if (error)
2348                 goto error_splat_root;
2349
2350         s->s_flags |= MS_ACTIVE;
2351         mnt->mnt_sb = s;
2352         mnt->mnt_root = mntroot;
2353         error = 0;
2354
2355 out:
2356         kfree(data->nfs_server.hostname);
2357         kfree(data->mount_server.hostname);
2358         kfree(data->fscache_uniq);
2359         security_free_mnt_opts(&data->lsm_opts);
2360 out_free_fh:
2361         nfs_free_fhandle(mntfh);
2362         kfree(data);
2363         return error;
2364
2365 out_err_nosb:
2366         nfs_free_server(server);
2367         goto out;
2368
2369 error_splat_root:
2370         dput(mntroot);
2371 error_splat_super:
2372         if (server && !s->s_root)
2373                 bdi_unregister(&server->backing_dev_info);
2374 error_splat_bdi:
2375         deactivate_locked_super(s);
2376         goto out;
2377 }
2378
2379 /*
2380  * Ensure that we unregister the bdi before kill_anon_super
2381  * releases the device name
2382  */
2383 static void nfs_put_super(struct super_block *s)
2384 {
2385         struct nfs_server *server = NFS_SB(s);
2386
2387         bdi_unregister(&server->backing_dev_info);
2388 }
2389
2390 /*
2391  * Destroy an NFS2/3 superblock
2392  */
2393 static void nfs_kill_super(struct super_block *s)
2394 {
2395         struct nfs_server *server = NFS_SB(s);
2396
2397         kill_anon_super(s);
2398         nfs_fscache_release_super_cookie(s);
2399         nfs_free_server(server);
2400 }
2401
2402 /*
2403  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2404  */
2405 static struct dentry *
2406 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2407                 const char *dev_name, void *raw_data)
2408 {
2409         struct nfs_clone_mount *data = raw_data;
2410         struct super_block *s;
2411         struct nfs_server *server;
2412         struct dentry *mntroot;
2413         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2414         struct nfs_sb_mountdata sb_mntdata = {
2415                 .mntflags = flags,
2416         };
2417         int error;
2418
2419         dprintk("--> nfs_xdev_mount()\n");
2420
2421         /* create a new volume representation */
2422         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2423         if (IS_ERR(server)) {
2424                 error = PTR_ERR(server);
2425                 goto out_err_noserver;
2426         }
2427         sb_mntdata.server = server;
2428
2429         if (server->flags & NFS_MOUNT_UNSHARED)
2430                 compare_super = NULL;
2431
2432         /* Get a superblock - note that we may end up sharing one that already exists */
2433         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2434         if (IS_ERR(s)) {
2435                 error = PTR_ERR(s);
2436                 goto out_err_nosb;
2437         }
2438
2439         if (s->s_fs_info != server) {
2440                 nfs_free_server(server);
2441                 server = NULL;
2442         } else {
2443                 error = nfs_bdi_register(server);
2444                 if (error)
2445                         goto error_splat_bdi;
2446         }
2447
2448         if (!s->s_root) {
2449                 /* initial superblock/root creation */
2450                 nfs_clone_super(s, data->sb);
2451                 nfs_fscache_get_super_cookie(s, NULL, data);
2452         }
2453
2454         mntroot = nfs_get_root(s, data->fh);
2455         if (IS_ERR(mntroot)) {
2456                 error = PTR_ERR(mntroot);
2457                 goto error_splat_super;
2458         }
2459         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2460                 dput(mntroot);
2461                 error = -ESTALE;
2462                 goto error_splat_super;
2463         }
2464
2465         s->s_flags |= MS_ACTIVE;
2466
2467         /* clone any lsm security options from the parent to the new sb */
2468         security_sb_clone_mnt_opts(data->sb, s);
2469
2470         dprintk("<-- nfs_xdev_mount() = 0\n");
2471         return mntroot;
2472
2473 out_err_nosb:
2474         nfs_free_server(server);
2475 out_err_noserver:
2476         dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2477         return ERR_PTR(error);
2478
2479 error_splat_super:
2480         if (server && !s->s_root)
2481                 bdi_unregister(&server->backing_dev_info);
2482 error_splat_bdi:
2483         deactivate_locked_super(s);
2484         dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2485         return ERR_PTR(error);
2486 }
2487
2488 #ifdef CONFIG_NFS_V4
2489
2490 /*
2491  * Finish setting up a cloned NFS4 superblock
2492  */
2493 static void nfs4_clone_super(struct super_block *sb,
2494                             const struct super_block *old_sb)
2495 {
2496         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2497         sb->s_blocksize = old_sb->s_blocksize;
2498         sb->s_maxbytes = old_sb->s_maxbytes;
2499         sb->s_time_gran = 1;
2500         sb->s_op = old_sb->s_op;
2501         nfs_initialise_sb(sb);
2502 }
2503
2504 /*
2505  * Set up an NFS4 superblock
2506  */
2507 static void nfs4_fill_super(struct super_block *sb)
2508 {
2509         sb->s_time_gran = 1;
2510         sb->s_op = &nfs4_sops;
2511         nfs_initialise_sb(sb);
2512 }
2513
2514 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2515 {
2516         args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2517                          NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2518 }
2519
2520 static int nfs4_validate_text_mount_data(void *options,
2521                                          struct nfs_parsed_mount_data *args,
2522                                          const char *dev_name)
2523 {
2524         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2525
2526         nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2527
2528         nfs_validate_transport_protocol(args);
2529
2530         nfs4_validate_mount_flags(args);
2531
2532         if (args->version != 4) {
2533                 dfprintk(MOUNT,
2534                          "NFS4: Illegal mount version\n");
2535                 return -EINVAL;
2536         }
2537
2538         if (args->auth_flavor_len > 1) {
2539                 dfprintk(MOUNT,
2540                          "NFS4: Too many RPC auth flavours specified\n");
2541                 return -EINVAL;
2542         }
2543
2544         if (args->client_address == NULL) {
2545                 dfprintk(MOUNT,
2546                          "NFS4: mount program didn't pass callback address\n");
2547                 return -EINVAL;
2548         }
2549
2550         return nfs_parse_devname(dev_name,
2551                                    &args->nfs_server.hostname,
2552                                    NFS4_MAXNAMLEN,
2553                                    &args->nfs_server.export_path,
2554                                    NFS4_MAXPATHLEN);
2555 }
2556
2557 /*
2558  * Validate NFSv4 mount options
2559  */
2560 static int nfs4_validate_mount_data(void *options,
2561                                     struct nfs_parsed_mount_data *args,
2562                                     const char *dev_name)
2563 {
2564         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2565         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2566         char *c;
2567
2568         if (data == NULL)
2569                 goto out_no_data;
2570
2571         switch (data->version) {
2572         case 1:
2573                 if (data->host_addrlen > sizeof(args->nfs_server.address))
2574                         goto out_no_address;
2575                 if (data->host_addrlen == 0)
2576                         goto out_no_address;
2577                 args->nfs_server.addrlen = data->host_addrlen;
2578                 if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2579                         return -EFAULT;
2580                 if (!nfs_verify_server_address(sap))
2581                         goto out_no_address;
2582
2583                 if (data->auth_flavourlen) {
2584                         if (data->auth_flavourlen > 1)
2585                                 goto out_inval_auth;
2586                         if (copy_from_user(&args->auth_flavors[0],
2587                                            data->auth_flavours,
2588                                            sizeof(args->auth_flavors[0])))
2589                                 return -EFAULT;
2590                 }
2591
2592                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2593                 if (IS_ERR(c))
2594                         return PTR_ERR(c);
2595                 args->nfs_server.hostname = c;
2596
2597                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2598                 if (IS_ERR(c))
2599                         return PTR_ERR(c);
2600                 args->nfs_server.export_path = c;
2601                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2602
2603                 c = strndup_user(data->client_addr.data, 16);
2604                 if (IS_ERR(c))
2605                         return PTR_ERR(c);
2606                 args->client_address = c;
2607
2608                 /*
2609                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2610                  * can deal with.
2611                  */
2612
2613                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
2614                 args->rsize     = data->rsize;
2615                 args->wsize     = data->wsize;
2616                 args->timeo     = data->timeo;
2617                 args->retrans   = data->retrans;
2618                 args->acregmin  = data->acregmin;
2619                 args->acregmax  = data->acregmax;
2620                 args->acdirmin  = data->acdirmin;
2621                 args->acdirmax  = data->acdirmax;
2622                 args->nfs_server.protocol = data->proto;
2623                 nfs_validate_transport_protocol(args);
2624
2625                 break;
2626         default:
2627                 if (nfs_parse_mount_options((char *)options, args) == 0)
2628                         return -EINVAL;
2629
2630                 if (!nfs_verify_server_address(sap))
2631                         return -EINVAL;
2632
2633                 return nfs4_validate_text_mount_data(options, args, dev_name);
2634         }
2635
2636         return 0;
2637
2638 out_no_data:
2639         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2640         return -EINVAL;
2641
2642 out_inval_auth:
2643         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2644                  data->auth_flavourlen);
2645         return -EINVAL;
2646
2647 out_no_address:
2648         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2649         return -EINVAL;
2650 }
2651
2652 /*
2653  * Get the superblock for the NFS4 root partition
2654  */
2655 static struct dentry *
2656 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2657                   const char *dev_name, void *raw_data)
2658 {
2659         struct nfs_parsed_mount_data *data = raw_data;
2660         struct super_block *s;
2661         struct nfs_server *server;
2662         struct nfs_fh *mntfh;
2663         struct dentry *mntroot;
2664         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2665         struct nfs_sb_mountdata sb_mntdata = {
2666                 .mntflags = flags,
2667         };
2668         int error = -ENOMEM;
2669
2670         mntfh = nfs_alloc_fhandle();
2671         if (data == NULL || mntfh == NULL)
2672                 goto out_free_fh;
2673
2674         security_init_mnt_opts(&data->lsm_opts);
2675
2676         /* Get a volume representation */
2677         server = nfs4_create_server(data, mntfh);
2678         if (IS_ERR(server)) {
2679                 error = PTR_ERR(server);
2680                 goto out;
2681         }
2682         sb_mntdata.server = server;
2683
2684         if (server->flags & NFS4_MOUNT_UNSHARED)
2685                 compare_super = NULL;
2686
2687         /* Get a superblock - note that we may end up sharing one that already exists */
2688         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2689         if (IS_ERR(s)) {
2690                 error = PTR_ERR(s);
2691                 goto out_free;
2692         }
2693
2694         if (s->s_fs_info != server) {
2695                 nfs_free_server(server);
2696                 server = NULL;
2697         } else {
2698                 error = nfs_bdi_register(server);
2699                 if (error)
2700                         goto error_splat_bdi;
2701         }
2702
2703         if (!s->s_root) {
2704                 /* initial superblock/root creation */
2705                 nfs4_fill_super(s);
2706                 nfs_fscache_get_super_cookie(
2707                         s, data ? data->fscache_uniq : NULL, NULL);
2708         }
2709
2710         mntroot = nfs4_get_root(s, mntfh);
2711         if (IS_ERR(mntroot)) {
2712                 error = PTR_ERR(mntroot);
2713                 goto error_splat_super;
2714         }
2715
2716         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2717         if (error)
2718                 goto error_splat_root;
2719
2720         s->s_flags |= MS_ACTIVE;
2721
2722         security_free_mnt_opts(&data->lsm_opts);
2723         nfs_free_fhandle(mntfh);
2724         return mntroot;
2725
2726 out:
2727         security_free_mnt_opts(&data->lsm_opts);
2728 out_free_fh:
2729         nfs_free_fhandle(mntfh);
2730         return ERR_PTR(error);
2731
2732 out_free:
2733         nfs_free_server(server);
2734         goto out;
2735
2736 error_splat_root:
2737         dput(mntroot);
2738 error_splat_super:
2739         if (server && !s->s_root)
2740                 bdi_unregister(&server->backing_dev_info);
2741 error_splat_bdi:
2742         deactivate_locked_super(s);
2743         goto out;
2744 }
2745
2746 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2747                 int flags, void *data, const char *hostname)
2748 {
2749         struct vfsmount *root_mnt;
2750         char *root_devname;
2751         size_t len;
2752
2753         len = strlen(hostname) + 3;
2754         root_devname = kmalloc(len, GFP_KERNEL);
2755         if (root_devname == NULL)
2756                 return ERR_PTR(-ENOMEM);
2757         snprintf(root_devname, len, "%s:/", hostname);
2758         root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2759         kfree(root_devname);
2760         return root_mnt;
2761 }
2762
2763 static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
2764 {
2765         char *page = (char *) __get_free_page(GFP_KERNEL);
2766         char *devname, *tmp;
2767
2768         if (page == NULL)
2769                 return;
2770         devname = nfs_path(path->mnt->mnt_devname,
2771                         path->mnt->mnt_root, path->dentry,
2772                         page, PAGE_SIZE);
2773         if (IS_ERR(devname))
2774                 goto out_freepage;
2775         tmp = kstrdup(devname, GFP_KERNEL);
2776         if (tmp == NULL)
2777                 goto out_freepage;
2778         kfree(mnt->mnt_devname);
2779         mnt->mnt_devname = tmp;
2780 out_freepage:
2781         free_page((unsigned long)page);
2782 }
2783
2784 struct nfs_referral_count {
2785         struct list_head list;
2786         const struct task_struct *task;
2787         unsigned int referral_count;
2788 };
2789
2790 static LIST_HEAD(nfs_referral_count_list);
2791 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2792
2793 static struct nfs_referral_count *nfs_find_referral_count(void)
2794 {
2795         struct nfs_referral_count *p;
2796
2797         list_for_each_entry(p, &nfs_referral_count_list, list) {
2798                 if (p->task == current)
2799                         return p;
2800         }
2801         return NULL;
2802 }
2803
2804 #define NFS_MAX_NESTED_REFERRALS 2
2805
2806 static int nfs_referral_loop_protect(void)
2807 {
2808         struct nfs_referral_count *p, *new;
2809         int ret = -ENOMEM;
2810
2811         new = kmalloc(sizeof(*new), GFP_KERNEL);
2812         if (!new)
2813                 goto out;
2814         new->task = current;
2815         new->referral_count = 1;
2816
2817         ret = 0;
2818         spin_lock(&nfs_referral_count_list_lock);
2819         p = nfs_find_referral_count();
2820         if (p != NULL) {
2821                 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2822                         ret = -ELOOP;
2823                 else
2824                         p->referral_count++;
2825         } else {
2826                 list_add(&new->list, &nfs_referral_count_list);
2827                 new = NULL;
2828         }
2829         spin_unlock(&nfs_referral_count_list_lock);
2830         kfree(new);
2831 out:
2832         return ret;
2833 }
2834
2835 static void nfs_referral_loop_unprotect(void)
2836 {
2837         struct nfs_referral_count *p;
2838
2839         spin_lock(&nfs_referral_count_list_lock);
2840         p = nfs_find_referral_count();
2841         p->referral_count--;
2842         if (p->referral_count == 0)
2843                 list_del(&p->list);
2844         else
2845                 p = NULL;
2846         spin_unlock(&nfs_referral_count_list_lock);
2847         kfree(p);
2848 }
2849
2850 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
2851                 const char *export_path, struct vfsmount *mnt_target)
2852 {
2853         struct nameidata *nd = NULL;
2854         struct mnt_namespace *ns_private;
2855         struct super_block *s;
2856         int ret;
2857
2858         nd = kmalloc(sizeof(*nd), GFP_KERNEL);
2859         if (nd == NULL)
2860                 return -ENOMEM;
2861
2862         ns_private = create_mnt_ns(root_mnt);
2863         ret = PTR_ERR(ns_private);
2864         if (IS_ERR(ns_private))
2865                 goto out_mntput;
2866
2867         ret = nfs_referral_loop_protect();
2868         if (ret != 0)
2869                 goto out_put_mnt_ns;
2870
2871         ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
2872                         export_path, LOOKUP_FOLLOW, nd);
2873
2874         nfs_referral_loop_unprotect();
2875         put_mnt_ns(ns_private);
2876
2877         if (ret != 0)
2878                 goto out_err;
2879
2880         s = nd->path.mnt->mnt_sb;
2881         atomic_inc(&s->s_active);
2882         mnt_target->mnt_sb = s;
2883         mnt_target->mnt_root = dget(nd->path.dentry);
2884
2885         /* Correct the device pathname */
2886         nfs_fix_devname(&nd->path, mnt_target);
2887
2888         path_put(&nd->path);
2889         kfree(nd);
2890         down_write(&s->s_umount);
2891         return 0;
2892 out_put_mnt_ns:
2893         put_mnt_ns(ns_private);
2894 out_mntput:
2895         mntput(root_mnt);
2896 out_err:
2897         kfree(nd);
2898         return ret;
2899 }
2900
2901 static int nfs4_try_mount(int flags, const char *dev_name,
2902                          struct nfs_parsed_mount_data *data,
2903                          struct vfsmount *mnt)
2904 {
2905         char *export_path;
2906         struct vfsmount *root_mnt;
2907         int error;
2908
2909         dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2910
2911         export_path = data->nfs_server.export_path;
2912         data->nfs_server.export_path = "/";
2913         root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2914                         data->nfs_server.hostname);
2915         data->nfs_server.export_path = export_path;
2916
2917         error = PTR_ERR(root_mnt);
2918         if (IS_ERR(root_mnt))
2919                 goto out;
2920
2921         error = nfs_follow_remote_path(root_mnt, export_path, mnt);
2922
2923 out:
2924         dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
2925                         error != 0 ? " [error]" : "");
2926         return error;
2927 }
2928
2929 /*
2930  * Get the superblock for an NFS4 mountpoint
2931  */
2932 static int nfs4_get_sb(struct file_system_type *fs_type,
2933         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2934 {
2935         struct nfs_parsed_mount_data *data;
2936         int error = -ENOMEM;
2937
2938         data = nfs_alloc_parsed_mount_data(4);
2939         if (data == NULL)
2940                 goto out_free_data;
2941
2942         /* Validate the mount data */
2943         error = nfs4_validate_mount_data(raw_data, data, dev_name);
2944         if (error < 0)
2945                 goto out;
2946
2947         error = nfs4_try_mount(flags, dev_name, data, mnt);
2948
2949 out:
2950         kfree(data->client_address);
2951         kfree(data->nfs_server.export_path);
2952         kfree(data->nfs_server.hostname);
2953         kfree(data->fscache_uniq);
2954 out_free_data:
2955         kfree(data);
2956         dprintk("<-- nfs4_get_sb() = %d%s\n", error,
2957                         error != 0 ? " [error]" : "");
2958         return error;
2959 }
2960
2961 static void nfs4_kill_super(struct super_block *sb)
2962 {
2963         struct nfs_server *server = NFS_SB(sb);
2964
2965         dprintk("--> %s\n", __func__);
2966         nfs_super_return_all_delegations(sb);
2967         kill_anon_super(sb);
2968         nfs_fscache_release_super_cookie(sb);
2969         nfs_free_server(server);
2970         dprintk("<-- %s\n", __func__);
2971 }
2972
2973 /*
2974  * Clone an NFS4 server record on xdev traversal (FSID-change)
2975  */
2976 static struct dentry *
2977 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2978                  const char *dev_name, void *raw_data)
2979 {
2980         struct nfs_clone_mount *data = raw_data;
2981         struct super_block *s;
2982         struct nfs_server *server;
2983         struct dentry *mntroot;
2984         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2985         struct nfs_sb_mountdata sb_mntdata = {
2986                 .mntflags = flags,
2987         };
2988         int error;
2989
2990         dprintk("--> nfs4_xdev_mount()\n");
2991
2992         /* create a new volume representation */
2993         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2994         if (IS_ERR(server)) {
2995                 error = PTR_ERR(server);
2996                 goto out_err_noserver;
2997         }
2998         sb_mntdata.server = server;
2999
3000         if (server->flags & NFS4_MOUNT_UNSHARED)
3001                 compare_super = NULL;
3002
3003         /* Get a superblock - note that we may end up sharing one that already exists */
3004         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3005         if (IS_ERR(s)) {
3006                 error = PTR_ERR(s);
3007                 goto out_err_nosb;
3008         }
3009
3010         if (s->s_fs_info != server) {
3011                 nfs_free_server(server);
3012                 server = NULL;
3013         } else {
3014                 error = nfs_bdi_register(server);
3015                 if (error)
3016                         goto error_splat_bdi;
3017         }
3018
3019         if (!s->s_root) {
3020                 /* initial superblock/root creation */
3021                 nfs4_clone_super(s, data->sb);
3022                 nfs_fscache_get_super_cookie(s, NULL, data);
3023         }
3024
3025         mntroot = nfs4_get_root(s, data->fh);
3026         if (IS_ERR(mntroot)) {
3027                 error = PTR_ERR(mntroot);
3028                 goto error_splat_super;
3029         }
3030         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3031                 dput(mntroot);
3032                 error = -ESTALE;
3033                 goto error_splat_super;
3034         }
3035
3036         s->s_flags |= MS_ACTIVE;
3037
3038         security_sb_clone_mnt_opts(data->sb, s);
3039
3040         dprintk("<-- nfs4_xdev_mount() = 0\n");
3041         return mntroot;
3042
3043 out_err_nosb:
3044         nfs_free_server(server);
3045 out_err_noserver:
3046         dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3047         return ERR_PTR(error);
3048
3049 error_splat_super:
3050         if (server && !s->s_root)
3051                 bdi_unregister(&server->backing_dev_info);
3052 error_splat_bdi:
3053         deactivate_locked_super(s);
3054         dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3055         return ERR_PTR(error);
3056 }
3057
3058 static struct dentry *
3059 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3060                            const char *dev_name, void *raw_data)
3061 {
3062         struct nfs_clone_mount *data = raw_data;
3063         struct super_block *s;
3064         struct nfs_server *server;
3065         struct dentry *mntroot;
3066         struct nfs_fh *mntfh;
3067         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3068         struct nfs_sb_mountdata sb_mntdata = {
3069                 .mntflags = flags,
3070         };
3071         int error = -ENOMEM;
3072
3073         dprintk("--> nfs4_referral_get_sb()\n");
3074
3075         mntfh = nfs_alloc_fhandle();
3076         if (mntfh == NULL)
3077                 goto out_err_nofh;
3078
3079         /* create a new volume representation */
3080         server = nfs4_create_referral_server(data, mntfh);
3081         if (IS_ERR(server)) {
3082                 error = PTR_ERR(server);
3083                 goto out_err_noserver;
3084         }
3085         sb_mntdata.server = server;
3086
3087         if (server->flags & NFS4_MOUNT_UNSHARED)
3088                 compare_super = NULL;
3089
3090         /* Get a superblock - note that we may end up sharing one that already exists */
3091         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3092         if (IS_ERR(s)) {
3093                 error = PTR_ERR(s);
3094                 goto out_err_nosb;
3095         }
3096
3097         if (s->s_fs_info != server) {
3098                 nfs_free_server(server);
3099                 server = NULL;
3100         } else {
3101                 error = nfs_bdi_register(server);
3102                 if (error)
3103                         goto error_splat_bdi;
3104         }
3105
3106         if (!s->s_root) {
3107                 /* initial superblock/root creation */
3108                 nfs4_fill_super(s);
3109                 nfs_fscache_get_super_cookie(s, NULL, data);
3110         }
3111
3112         mntroot = nfs4_get_root(s, mntfh);
3113         if (IS_ERR(mntroot)) {
3114                 error = PTR_ERR(mntroot);
3115                 goto error_splat_super;
3116         }
3117         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3118                 dput(mntroot);
3119                 error = -ESTALE;
3120                 goto error_splat_super;
3121         }
3122
3123         s->s_flags |= MS_ACTIVE;
3124
3125         security_sb_clone_mnt_opts(data->sb, s);
3126
3127         nfs_free_fhandle(mntfh);
3128         dprintk("<-- nfs4_referral_get_sb() = 0\n");
3129         return mntroot;
3130
3131 out_err_nosb:
3132         nfs_free_server(server);
3133 out_err_noserver:
3134         nfs_free_fhandle(mntfh);
3135 out_err_nofh:
3136         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3137         return ERR_PTR(error);
3138
3139 error_splat_super:
3140         if (server && !s->s_root)
3141                 bdi_unregister(&server->backing_dev_info);
3142 error_splat_bdi:
3143         deactivate_locked_super(s);
3144         nfs_free_fhandle(mntfh);
3145         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3146         return ERR_PTR(error);
3147 }
3148
3149 /*
3150  * Create an NFS4 server record on referral traversal
3151  */
3152 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
3153                 int flags, const char *dev_name, void *raw_data,
3154                 struct vfsmount *mnt)
3155 {
3156         struct nfs_clone_mount *data = raw_data;
3157         char *export_path;
3158         struct vfsmount *root_mnt;
3159         int error;
3160
3161         dprintk("--> nfs4_referral_get_sb()\n");
3162
3163         export_path = data->mnt_path;
3164         data->mnt_path = "/";
3165
3166         root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3167                         flags, data, data->hostname);
3168         data->mnt_path = export_path;
3169
3170         error = PTR_ERR(root_mnt);
3171         if (IS_ERR(root_mnt))
3172                 goto out;
3173
3174         error = nfs_follow_remote_path(root_mnt, export_path, mnt);
3175 out:
3176         dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
3177                         error != 0 ? " [error]" : "");
3178         return error;
3179 }
3180
3181 #endif /* CONFIG_NFS_V4 */