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                 case Opt_v4:
1073                         mnt->flags &= ~NFS_MOUNT_VER3;
1074                         mnt->version = 4;
1075                         break;
1076                 case Opt_udp:
1077                         mnt->flags &= ~NFS_MOUNT_TCP;
1078                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1079                         break;
1080                 case Opt_tcp:
1081                         mnt->flags |= NFS_MOUNT_TCP;
1082                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1083                         break;
1084                 case Opt_rdma:
1085                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1086                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1087                         xprt_load_transport(p);
1088                         break;
1089                 case Opt_acl:
1090                         mnt->flags &= ~NFS_MOUNT_NOACL;
1091                         break;
1092                 case Opt_noacl:
1093                         mnt->flags |= NFS_MOUNT_NOACL;
1094                         break;
1095                 case Opt_rdirplus:
1096                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1097                         break;
1098                 case Opt_nordirplus:
1099                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1100                         break;
1101                 case Opt_sharecache:
1102                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
1103                         break;
1104                 case Opt_nosharecache:
1105                         mnt->flags |= NFS_MOUNT_UNSHARED;
1106                         break;
1107                 case Opt_resvport:
1108                         mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1109                         break;
1110                 case Opt_noresvport:
1111                         mnt->flags |= NFS_MOUNT_NORESVPORT;
1112                         break;
1113                 case Opt_fscache:
1114                         mnt->options |= NFS_OPTION_FSCACHE;
1115                         kfree(mnt->fscache_uniq);
1116                         mnt->fscache_uniq = NULL;
1117                         break;
1118                 case Opt_nofscache:
1119                         mnt->options &= ~NFS_OPTION_FSCACHE;
1120                         kfree(mnt->fscache_uniq);
1121                         mnt->fscache_uniq = NULL;
1122                         break;
1123
1124                 /*
1125                  * options that take numeric values
1126                  */
1127                 case Opt_port:
1128                         string = match_strdup(args);
1129                         if (string == NULL)
1130                                 goto out_nomem;
1131                         rc = strict_strtoul(string, 10, &option);
1132                         kfree(string);
1133                         if (rc != 0 || option > USHRT_MAX)
1134                                 goto out_invalid_value;
1135                         mnt->nfs_server.port = option;
1136                         break;
1137                 case Opt_rsize:
1138                         string = match_strdup(args);
1139                         if (string == NULL)
1140                                 goto out_nomem;
1141                         rc = strict_strtoul(string, 10, &option);
1142                         kfree(string);
1143                         if (rc != 0)
1144                                 goto out_invalid_value;
1145                         mnt->rsize = option;
1146                         break;
1147                 case Opt_wsize:
1148                         string = match_strdup(args);
1149                         if (string == NULL)
1150                                 goto out_nomem;
1151                         rc = strict_strtoul(string, 10, &option);
1152                         kfree(string);
1153                         if (rc != 0)
1154                                 goto out_invalid_value;
1155                         mnt->wsize = option;
1156                         break;
1157                 case Opt_bsize:
1158                         string = match_strdup(args);
1159                         if (string == NULL)
1160                                 goto out_nomem;
1161                         rc = strict_strtoul(string, 10, &option);
1162                         kfree(string);
1163                         if (rc != 0)
1164                                 goto out_invalid_value;
1165                         mnt->bsize = option;
1166                         break;
1167                 case Opt_timeo:
1168                         string = match_strdup(args);
1169                         if (string == NULL)
1170                                 goto out_nomem;
1171                         rc = strict_strtoul(string, 10, &option);
1172                         kfree(string);
1173                         if (rc != 0 || option == 0)
1174                                 goto out_invalid_value;
1175                         mnt->timeo = option;
1176                         break;
1177                 case Opt_retrans:
1178                         string = match_strdup(args);
1179                         if (string == NULL)
1180                                 goto out_nomem;
1181                         rc = strict_strtoul(string, 10, &option);
1182                         kfree(string);
1183                         if (rc != 0 || option == 0)
1184                                 goto out_invalid_value;
1185                         mnt->retrans = option;
1186                         break;
1187                 case Opt_acregmin:
1188                         string = match_strdup(args);
1189                         if (string == NULL)
1190                                 goto out_nomem;
1191                         rc = strict_strtoul(string, 10, &option);
1192                         kfree(string);
1193                         if (rc != 0)
1194                                 goto out_invalid_value;
1195                         mnt->acregmin = option;
1196                         break;
1197                 case Opt_acregmax:
1198                         string = match_strdup(args);
1199                         if (string == NULL)
1200                                 goto out_nomem;
1201                         rc = strict_strtoul(string, 10, &option);
1202                         kfree(string);
1203                         if (rc != 0)
1204                                 goto out_invalid_value;
1205                         mnt->acregmax = option;
1206                         break;
1207                 case Opt_acdirmin:
1208                         string = match_strdup(args);
1209                         if (string == NULL)
1210                                 goto out_nomem;
1211                         rc = strict_strtoul(string, 10, &option);
1212                         kfree(string);
1213                         if (rc != 0)
1214                                 goto out_invalid_value;
1215                         mnt->acdirmin = option;
1216                         break;
1217                 case Opt_acdirmax:
1218                         string = match_strdup(args);
1219                         if (string == NULL)
1220                                 goto out_nomem;
1221                         rc = strict_strtoul(string, 10, &option);
1222                         kfree(string);
1223                         if (rc != 0)
1224                                 goto out_invalid_value;
1225                         mnt->acdirmax = option;
1226                         break;
1227                 case Opt_actimeo:
1228                         string = match_strdup(args);
1229                         if (string == NULL)
1230                                 goto out_nomem;
1231                         rc = strict_strtoul(string, 10, &option);
1232                         kfree(string);
1233                         if (rc != 0)
1234                                 goto out_invalid_value;
1235                         mnt->acregmin = mnt->acregmax =
1236                         mnt->acdirmin = mnt->acdirmax = option;
1237                         break;
1238                 case Opt_namelen:
1239                         string = match_strdup(args);
1240                         if (string == NULL)
1241                                 goto out_nomem;
1242                         rc = strict_strtoul(string, 10, &option);
1243                         kfree(string);
1244                         if (rc != 0)
1245                                 goto out_invalid_value;
1246                         mnt->namlen = option;
1247                         break;
1248                 case Opt_mountport:
1249                         string = match_strdup(args);
1250                         if (string == NULL)
1251                                 goto out_nomem;
1252                         rc = strict_strtoul(string, 10, &option);
1253                         kfree(string);
1254                         if (rc != 0 || option > USHRT_MAX)
1255                                 goto out_invalid_value;
1256                         mnt->mount_server.port = option;
1257                         break;
1258                 case Opt_mountvers:
1259                         string = match_strdup(args);
1260                         if (string == NULL)
1261                                 goto out_nomem;
1262                         rc = strict_strtoul(string, 10, &option);
1263                         kfree(string);
1264                         if (rc != 0 ||
1265                             option < NFS_MNT_VERSION ||
1266                             option > NFS_MNT3_VERSION)
1267                                 goto out_invalid_value;
1268                         mnt->mount_server.version = option;
1269                         break;
1270                 case Opt_nfsvers:
1271                         string = match_strdup(args);
1272                         if (string == NULL)
1273                                 goto out_nomem;
1274                         rc = strict_strtoul(string, 10, &option);
1275                         kfree(string);
1276                         if (rc != 0)
1277                                 goto out_invalid_value;
1278                         switch (option) {
1279                         case NFS2_VERSION:
1280                                 mnt->flags &= ~NFS_MOUNT_VER3;
1281                                 mnt->version = 2;
1282                                 break;
1283                         case NFS3_VERSION:
1284                                 mnt->flags |= NFS_MOUNT_VER3;
1285                                 mnt->version = 3;
1286                                 break;
1287                         case NFS4_VERSION:
1288                                 mnt->flags &= ~NFS_MOUNT_VER3;
1289                                 mnt->version = 4;
1290                                 break;
1291                         default:
1292                                 goto out_invalid_value;
1293                         }
1294                         break;
1295                 case Opt_minorversion:
1296                         string = match_strdup(args);
1297                         if (string == NULL)
1298                                 goto out_nomem;
1299                         rc = strict_strtoul(string, 10, &option);
1300                         kfree(string);
1301                         if (rc != 0)
1302                                 goto out_invalid_value;
1303                         if (option > NFS4_MAX_MINOR_VERSION)
1304                                 goto out_invalid_value;
1305                         mnt->minorversion = option;
1306                         break;
1307
1308                 /*
1309                  * options that take text values
1310                  */
1311                 case Opt_sec:
1312                         string = match_strdup(args);
1313                         if (string == NULL)
1314                                 goto out_nomem;
1315                         rc = nfs_parse_security_flavors(string, mnt);
1316                         kfree(string);
1317                         if (!rc) {
1318                                 dfprintk(MOUNT, "NFS:   unrecognized "
1319                                                 "security flavor\n");
1320                                 return 0;
1321                         }
1322                         break;
1323                 case Opt_proto:
1324                         string = match_strdup(args);
1325                         if (string == NULL)
1326                                 goto out_nomem;
1327                         token = match_token(string,
1328                                             nfs_xprt_protocol_tokens, args);
1329
1330                         protofamily = AF_INET;
1331                         switch (token) {
1332                         case Opt_xprt_udp6:
1333                                 protofamily = AF_INET6;
1334                         case Opt_xprt_udp:
1335                                 mnt->flags &= ~NFS_MOUNT_TCP;
1336                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1337                                 kfree(string);
1338                                 break;
1339                         case Opt_xprt_tcp6:
1340                                 protofamily = AF_INET6;
1341                         case Opt_xprt_tcp:
1342                                 mnt->flags |= NFS_MOUNT_TCP;
1343                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1344                                 kfree(string);
1345                                 break;
1346                         case Opt_xprt_rdma:
1347                                 /* vector side protocols to TCP */
1348                                 mnt->flags |= NFS_MOUNT_TCP;
1349                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1350                                 xprt_load_transport(string);
1351                                 kfree(string);
1352                                 break;
1353                         default:
1354                                 dfprintk(MOUNT, "NFS:   unrecognized "
1355                                                 "transport protocol\n");
1356                                 kfree(string);
1357                                 return 0;
1358                         }
1359                         break;
1360                 case Opt_mountproto:
1361                         string = match_strdup(args);
1362                         if (string == NULL)
1363                                 goto out_nomem;
1364                         token = match_token(string,
1365                                             nfs_xprt_protocol_tokens, args);
1366                         kfree(string);
1367
1368                         mountfamily = AF_INET;
1369                         switch (token) {
1370                         case Opt_xprt_udp6:
1371                                 mountfamily = AF_INET6;
1372                         case Opt_xprt_udp:
1373                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1374                                 break;
1375                         case Opt_xprt_tcp6:
1376                                 mountfamily = AF_INET6;
1377                         case Opt_xprt_tcp:
1378                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1379                                 break;
1380                         case Opt_xprt_rdma: /* not used for side protocols */
1381                         default:
1382                                 dfprintk(MOUNT, "NFS:   unrecognized "
1383                                                 "transport protocol\n");
1384                                 return 0;
1385                         }
1386                         break;
1387                 case Opt_addr:
1388                         string = match_strdup(args);
1389                         if (string == NULL)
1390                                 goto out_nomem;
1391                         mnt->nfs_server.addrlen =
1392                                 rpc_pton(string, strlen(string),
1393                                         (struct sockaddr *)
1394                                         &mnt->nfs_server.address,
1395                                         sizeof(mnt->nfs_server.address));
1396                         kfree(string);
1397                         if (mnt->nfs_server.addrlen == 0)
1398                                 goto out_invalid_address;
1399                         break;
1400                 case Opt_clientaddr:
1401                         string = match_strdup(args);
1402                         if (string == NULL)
1403                                 goto out_nomem;
1404                         kfree(mnt->client_address);
1405                         mnt->client_address = string;
1406                         break;
1407                 case Opt_mounthost:
1408                         string = match_strdup(args);
1409                         if (string == NULL)
1410                                 goto out_nomem;
1411                         kfree(mnt->mount_server.hostname);
1412                         mnt->mount_server.hostname = string;
1413                         break;
1414                 case Opt_mountaddr:
1415                         string = match_strdup(args);
1416                         if (string == NULL)
1417                                 goto out_nomem;
1418                         mnt->mount_server.addrlen =
1419                                 rpc_pton(string, strlen(string),
1420                                         (struct sockaddr *)
1421                                         &mnt->mount_server.address,
1422                                         sizeof(mnt->mount_server.address));
1423                         kfree(string);
1424                         if (mnt->mount_server.addrlen == 0)
1425                                 goto out_invalid_address;
1426                         break;
1427                 case Opt_lookupcache:
1428                         string = match_strdup(args);
1429                         if (string == NULL)
1430                                 goto out_nomem;
1431                         token = match_token(string,
1432                                         nfs_lookupcache_tokens, args);
1433                         kfree(string);
1434                         switch (token) {
1435                                 case Opt_lookupcache_all:
1436                                         mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1437                                         break;
1438                                 case Opt_lookupcache_positive:
1439                                         mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1440                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1441                                         break;
1442                                 case Opt_lookupcache_none:
1443                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1444                                         break;
1445                                 default:
1446                                         dfprintk(MOUNT, "NFS:   invalid "
1447                                                         "lookupcache argument\n");
1448                                         return 0;
1449                         };
1450                         break;
1451                 case Opt_fscache_uniq:
1452                         string = match_strdup(args);
1453                         if (string == NULL)
1454                                 goto out_nomem;
1455                         kfree(mnt->fscache_uniq);
1456                         mnt->fscache_uniq = string;
1457                         mnt->options |= NFS_OPTION_FSCACHE;
1458                         break;
1459                 case Opt_local_lock:
1460                         string = match_strdup(args);
1461                         if (string == NULL)
1462                                 goto out_nomem;
1463                         token = match_token(string, nfs_local_lock_tokens,
1464                                         args);
1465                         kfree(string);
1466                         switch (token) {
1467                         case Opt_local_lock_all:
1468                                 mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1469                                                NFS_MOUNT_LOCAL_FCNTL);
1470                                 break;
1471                         case Opt_local_lock_flock:
1472                                 mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1473                                 break;
1474                         case Opt_local_lock_posix:
1475                                 mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1476                                 break;
1477                         case Opt_local_lock_none:
1478                                 mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1479                                                 NFS_MOUNT_LOCAL_FCNTL);
1480                                 break;
1481                         default:
1482                                 dfprintk(MOUNT, "NFS:   invalid "
1483                                                 "local_lock argument\n");
1484                                 return 0;
1485                         };
1486                         break;
1487
1488                 /*
1489                  * Special options
1490                  */
1491                 case Opt_sloppy:
1492                         sloppy = 1;
1493                         dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1494                         break;
1495                 case Opt_userspace:
1496                 case Opt_deprecated:
1497                         dfprintk(MOUNT, "NFS:   ignoring mount option "
1498                                         "'%s'\n", p);
1499                         break;
1500
1501                 default:
1502                         invalid_option = 1;
1503                         dfprintk(MOUNT, "NFS:   unrecognized mount option "
1504                                         "'%s'\n", p);
1505                 }
1506         }
1507
1508         if (!sloppy && invalid_option)
1509                 return 0;
1510
1511         /*
1512          * verify that any proto=/mountproto= options match the address
1513          * familiies in the addr=/mountaddr= options.
1514          */
1515         if (protofamily != AF_UNSPEC &&
1516             protofamily != mnt->nfs_server.address.ss_family)
1517                 goto out_proto_mismatch;
1518
1519         if (mountfamily != AF_UNSPEC) {
1520                 if (mnt->mount_server.addrlen) {
1521                         if (mountfamily != mnt->mount_server.address.ss_family)
1522                                 goto out_mountproto_mismatch;
1523                 } else {
1524                         if (mountfamily != mnt->nfs_server.address.ss_family)
1525                                 goto out_mountproto_mismatch;
1526                 }
1527         }
1528
1529         return 1;
1530
1531 out_mountproto_mismatch:
1532         printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1533                          "option\n");
1534         return 0;
1535 out_proto_mismatch:
1536         printk(KERN_INFO "NFS: server address does not match proto= option\n");
1537         return 0;
1538 out_invalid_address:
1539         printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1540         return 0;
1541 out_invalid_value:
1542         printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1543         return 0;
1544 out_nomem:
1545         printk(KERN_INFO "NFS: not enough memory to parse option\n");
1546         return 0;
1547 out_security_failure:
1548         free_secdata(secdata);
1549         printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1550         return 0;
1551 }
1552
1553 /*
1554  * Match the requested auth flavors with the list returned by
1555  * the server.  Returns zero and sets the mount's authentication
1556  * flavor on success; returns -EACCES if server does not support
1557  * the requested flavor.
1558  */
1559 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1560                              struct nfs_mount_request *request)
1561 {
1562         unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1563
1564         /*
1565          * Certain releases of Linux's mountd return an empty
1566          * flavor list.  To prevent behavioral regression with
1567          * these servers (ie. rejecting mounts that used to
1568          * succeed), revert to pre-2.6.32 behavior (no checking)
1569          * if the returned flavor list is empty.
1570          */
1571         if (server_authlist_len == 0)
1572                 return 0;
1573
1574         /*
1575          * We avoid sophisticated negotiating here, as there are
1576          * plenty of cases where we can get it wrong, providing
1577          * either too little or too much security.
1578          *
1579          * RFC 2623, section 2.7 suggests we SHOULD prefer the
1580          * flavor listed first.  However, some servers list
1581          * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1582          * preferred default, in args->auth_flavors[0] if user
1583          * didn't specify sec= mount option.
1584          */
1585         for (i = 0; i < args->auth_flavor_len; i++)
1586                 for (j = 0; j < server_authlist_len; j++)
1587                         if (args->auth_flavors[i] == request->auth_flavs[j]) {
1588                                 dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1589                                         request->auth_flavs[j]);
1590                                 args->auth_flavors[0] = request->auth_flavs[j];
1591                                 return 0;
1592                         }
1593
1594         dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1595         nfs_umount(request);
1596         return -EACCES;
1597 }
1598
1599 /*
1600  * Use the remote server's MOUNT service to request the NFS file handle
1601  * corresponding to the provided path.
1602  */
1603 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1604                          struct nfs_fh *root_fh)
1605 {
1606         rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1607         unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1608         struct nfs_mount_request request = {
1609                 .sap            = (struct sockaddr *)
1610                                                 &args->mount_server.address,
1611                 .dirpath        = args->nfs_server.export_path,
1612                 .protocol       = args->mount_server.protocol,
1613                 .fh             = root_fh,
1614                 .noresvport     = args->flags & NFS_MOUNT_NORESVPORT,
1615                 .auth_flav_len  = &server_authlist_len,
1616                 .auth_flavs     = server_authlist,
1617         };
1618         int status;
1619
1620         if (args->mount_server.version == 0) {
1621                 switch (args->version) {
1622                         default:
1623                                 args->mount_server.version = NFS_MNT3_VERSION;
1624                                 break;
1625                         case 2:
1626                                 args->mount_server.version = NFS_MNT_VERSION;
1627                 }
1628         }
1629         request.version = args->mount_server.version;
1630
1631         if (args->mount_server.hostname)
1632                 request.hostname = args->mount_server.hostname;
1633         else
1634                 request.hostname = args->nfs_server.hostname;
1635
1636         /*
1637          * Construct the mount server's address.
1638          */
1639         if (args->mount_server.address.ss_family == AF_UNSPEC) {
1640                 memcpy(request.sap, &args->nfs_server.address,
1641                        args->nfs_server.addrlen);
1642                 args->mount_server.addrlen = args->nfs_server.addrlen;
1643         }
1644         request.salen = args->mount_server.addrlen;
1645         nfs_set_port(request.sap, &args->mount_server.port, 0);
1646
1647         /*
1648          * Now ask the mount server to map our export path
1649          * to a file handle.
1650          */
1651         status = nfs_mount(&request);
1652         if (status != 0) {
1653                 dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1654                                 request.hostname, status);
1655                 return status;
1656         }
1657
1658         /*
1659          * MNTv1 (NFSv2) does not support auth flavor negotiation.
1660          */
1661         if (args->mount_server.version != NFS_MNT3_VERSION)
1662                 return 0;
1663         return nfs_walk_authlist(args, &request);
1664 }
1665
1666 static int nfs_parse_simple_hostname(const char *dev_name,
1667                                      char **hostname, size_t maxnamlen,
1668                                      char **export_path, size_t maxpathlen)
1669 {
1670         size_t len;
1671         char *colon, *comma;
1672
1673         colon = strchr(dev_name, ':');
1674         if (colon == NULL)
1675                 goto out_bad_devname;
1676
1677         len = colon - dev_name;
1678         if (len > maxnamlen)
1679                 goto out_hostname;
1680
1681         /* N.B. caller will free nfs_server.hostname in all cases */
1682         *hostname = kstrndup(dev_name, len, GFP_KERNEL);
1683         if (!*hostname)
1684                 goto out_nomem;
1685
1686         /* kill possible hostname list: not supported */
1687         comma = strchr(*hostname, ',');
1688         if (comma != NULL) {
1689                 if (comma == *hostname)
1690                         goto out_bad_devname;
1691                 *comma = '\0';
1692         }
1693
1694         colon++;
1695         len = strlen(colon);
1696         if (len > maxpathlen)
1697                 goto out_path;
1698         *export_path = kstrndup(colon, len, GFP_KERNEL);
1699         if (!*export_path)
1700                 goto out_nomem;
1701
1702         dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1703         return 0;
1704
1705 out_bad_devname:
1706         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1707         return -EINVAL;
1708
1709 out_nomem:
1710         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1711         return -ENOMEM;
1712
1713 out_hostname:
1714         dfprintk(MOUNT, "NFS: server hostname too long\n");
1715         return -ENAMETOOLONG;
1716
1717 out_path:
1718         dfprintk(MOUNT, "NFS: export pathname too long\n");
1719         return -ENAMETOOLONG;
1720 }
1721
1722 /*
1723  * Hostname has square brackets around it because it contains one or
1724  * more colons.  We look for the first closing square bracket, and a
1725  * colon must follow it.
1726  */
1727 static int nfs_parse_protected_hostname(const char *dev_name,
1728                                         char **hostname, size_t maxnamlen,
1729                                         char **export_path, size_t maxpathlen)
1730 {
1731         size_t len;
1732         char *start, *end;
1733
1734         start = (char *)(dev_name + 1);
1735
1736         end = strchr(start, ']');
1737         if (end == NULL)
1738                 goto out_bad_devname;
1739         if (*(end + 1) != ':')
1740                 goto out_bad_devname;
1741
1742         len = end - start;
1743         if (len > maxnamlen)
1744                 goto out_hostname;
1745
1746         /* N.B. caller will free nfs_server.hostname in all cases */
1747         *hostname = kstrndup(start, len, GFP_KERNEL);
1748         if (*hostname == NULL)
1749                 goto out_nomem;
1750
1751         end += 2;
1752         len = strlen(end);
1753         if (len > maxpathlen)
1754                 goto out_path;
1755         *export_path = kstrndup(end, len, GFP_KERNEL);
1756         if (!*export_path)
1757                 goto out_nomem;
1758
1759         return 0;
1760
1761 out_bad_devname:
1762         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1763         return -EINVAL;
1764
1765 out_nomem:
1766         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1767         return -ENOMEM;
1768
1769 out_hostname:
1770         dfprintk(MOUNT, "NFS: server hostname too long\n");
1771         return -ENAMETOOLONG;
1772
1773 out_path:
1774         dfprintk(MOUNT, "NFS: export pathname too long\n");
1775         return -ENAMETOOLONG;
1776 }
1777
1778 /*
1779  * Split "dev_name" into "hostname:export_path".
1780  *
1781  * The leftmost colon demarks the split between the server's hostname
1782  * and the export path.  If the hostname starts with a left square
1783  * bracket, then it may contain colons.
1784  *
1785  * Note: caller frees hostname and export path, even on error.
1786  */
1787 static int nfs_parse_devname(const char *dev_name,
1788                              char **hostname, size_t maxnamlen,
1789                              char **export_path, size_t maxpathlen)
1790 {
1791         if (*dev_name == '[')
1792                 return nfs_parse_protected_hostname(dev_name,
1793                                                     hostname, maxnamlen,
1794                                                     export_path, maxpathlen);
1795
1796         return nfs_parse_simple_hostname(dev_name,
1797                                          hostname, maxnamlen,
1798                                          export_path, maxpathlen);
1799 }
1800
1801 /*
1802  * Validate the NFS2/NFS3 mount data
1803  * - fills in the mount root filehandle
1804  *
1805  * For option strings, user space handles the following behaviors:
1806  *
1807  * + DNS: mapping server host name to IP address ("addr=" option)
1808  *
1809  * + failure mode: how to behave if a mount request can't be handled
1810  *   immediately ("fg/bg" option)
1811  *
1812  * + retry: how often to retry a mount request ("retry=" option)
1813  *
1814  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1815  *   mountproto=tcp after mountproto=udp, and so on
1816  */
1817 static int nfs_validate_mount_data(void *options,
1818                                    struct nfs_parsed_mount_data *args,
1819                                    struct nfs_fh *mntfh,
1820                                    const char *dev_name)
1821 {
1822         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1823         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1824
1825         if (data == NULL)
1826                 goto out_no_data;
1827
1828         switch (data->version) {
1829         case 1:
1830                 data->namlen = 0;
1831         case 2:
1832                 data->bsize = 0;
1833         case 3:
1834                 if (data->flags & NFS_MOUNT_VER3)
1835                         goto out_no_v3;
1836                 data->root.size = NFS2_FHSIZE;
1837                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1838         case 4:
1839                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1840                         goto out_no_sec;
1841         case 5:
1842                 memset(data->context, 0, sizeof(data->context));
1843         case 6:
1844                 if (data->flags & NFS_MOUNT_VER3) {
1845                         if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1846                                 goto out_invalid_fh;
1847                         mntfh->size = data->root.size;
1848                         args->version = 3;
1849                 } else {
1850                         mntfh->size = NFS2_FHSIZE;
1851                         args->version = 2;
1852                 }
1853
1854
1855                 memcpy(mntfh->data, data->root.data, mntfh->size);
1856                 if (mntfh->size < sizeof(mntfh->data))
1857                         memset(mntfh->data + mntfh->size, 0,
1858                                sizeof(mntfh->data) - mntfh->size);
1859
1860                 /*
1861                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1862                  * can deal with.
1863                  */
1864                 args->flags             = data->flags & NFS_MOUNT_FLAGMASK;
1865                 args->flags             |= NFS_MOUNT_LEGACY_INTERFACE;
1866                 args->rsize             = data->rsize;
1867                 args->wsize             = data->wsize;
1868                 args->timeo             = data->timeo;
1869                 args->retrans           = data->retrans;
1870                 args->acregmin          = data->acregmin;
1871                 args->acregmax          = data->acregmax;
1872                 args->acdirmin          = data->acdirmin;
1873                 args->acdirmax          = data->acdirmax;
1874
1875                 memcpy(sap, &data->addr, sizeof(data->addr));
1876                 args->nfs_server.addrlen = sizeof(data->addr);
1877                 if (!nfs_verify_server_address(sap))
1878                         goto out_no_address;
1879
1880                 if (!(data->flags & NFS_MOUNT_TCP))
1881                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1882                 /* N.B. caller will free nfs_server.hostname in all cases */
1883                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1884                 args->namlen            = data->namlen;
1885                 args->bsize             = data->bsize;
1886
1887                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1888                         args->auth_flavors[0] = data->pseudoflavor;
1889                 if (!args->nfs_server.hostname)
1890                         goto out_nomem;
1891
1892                 if (!(data->flags & NFS_MOUNT_NONLM))
1893                         args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1894                                          NFS_MOUNT_LOCAL_FCNTL);
1895                 else
1896                         args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1897                                         NFS_MOUNT_LOCAL_FCNTL);
1898                 /*
1899                  * The legacy version 6 binary mount data from userspace has a
1900                  * field used only to transport selinux information into the
1901                  * the kernel.  To continue to support that functionality we
1902                  * have a touch of selinux knowledge here in the NFS code. The
1903                  * userspace code converted context=blah to just blah so we are
1904                  * converting back to the full string selinux understands.
1905                  */
1906                 if (data->context[0]){
1907 #ifdef CONFIG_SECURITY_SELINUX
1908                         int rc;
1909                         char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1910                         if (!opts_str)
1911                                 return -ENOMEM;
1912                         strcpy(opts_str, "context=");
1913                         data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1914                         strcat(opts_str, &data->context[0]);
1915                         rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1916                         kfree(opts_str);
1917                         if (rc)
1918                                 return rc;
1919 #else
1920                         return -EINVAL;
1921 #endif
1922                 }
1923
1924                 break;
1925         default: {
1926                 int status;
1927
1928                 if (nfs_parse_mount_options((char *)options, args) == 0)
1929                         return -EINVAL;
1930
1931                 if (!nfs_verify_server_address(sap))
1932                         goto out_no_address;
1933
1934                 if (args->version == 4)
1935 #ifdef CONFIG_NFS_V4
1936                         return nfs4_validate_text_mount_data(options,
1937                                                              args, dev_name);
1938 #else
1939                         goto out_v4_not_compiled;
1940 #endif
1941
1942                 nfs_set_port(sap, &args->nfs_server.port, 0);
1943
1944                 nfs_set_mount_transport_protocol(args);
1945
1946                 status = nfs_parse_devname(dev_name,
1947                                            &args->nfs_server.hostname,
1948                                            PAGE_SIZE,
1949                                            &args->nfs_server.export_path,
1950                                            NFS_MAXPATHLEN);
1951                 if (!status)
1952                         status = nfs_try_mount(args, mntfh);
1953
1954                 kfree(args->nfs_server.export_path);
1955                 args->nfs_server.export_path = NULL;
1956
1957                 if (status)
1958                         return status;
1959
1960                 break;
1961                 }
1962         }
1963
1964 #ifndef CONFIG_NFS_V3
1965         if (args->version == 3)
1966                 goto out_v3_not_compiled;
1967 #endif /* !CONFIG_NFS_V3 */
1968
1969         return 0;
1970
1971 out_no_data:
1972         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1973         return -EINVAL;
1974
1975 out_no_v3:
1976         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1977                  data->version);
1978         return -EINVAL;
1979
1980 out_no_sec:
1981         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1982         return -EINVAL;
1983
1984 #ifndef CONFIG_NFS_V3
1985 out_v3_not_compiled:
1986         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1987         return -EPROTONOSUPPORT;
1988 #endif /* !CONFIG_NFS_V3 */
1989
1990 #ifndef CONFIG_NFS_V4
1991 out_v4_not_compiled:
1992         dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1993         return -EPROTONOSUPPORT;
1994 #endif /* !CONFIG_NFS_V4 */
1995
1996 out_nomem:
1997         dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1998         return -ENOMEM;
1999
2000 out_no_address:
2001         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2002         return -EINVAL;
2003
2004 out_invalid_fh:
2005         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2006         return -EINVAL;
2007 }
2008
2009 static int
2010 nfs_compare_remount_data(struct nfs_server *nfss,
2011                          struct nfs_parsed_mount_data *data)
2012 {
2013         if (data->flags != nfss->flags ||
2014             data->rsize != nfss->rsize ||
2015             data->wsize != nfss->wsize ||
2016             data->retrans != nfss->client->cl_timeout->to_retries ||
2017             data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2018             data->acregmin != nfss->acregmin / HZ ||
2019             data->acregmax != nfss->acregmax / HZ ||
2020             data->acdirmin != nfss->acdirmin / HZ ||
2021             data->acdirmax != nfss->acdirmax / HZ ||
2022             data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2023             data->nfs_server.port != nfss->port ||
2024             data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2025             !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2026                           (struct sockaddr *)&nfss->nfs_client->cl_addr))
2027                 return -EINVAL;
2028
2029         return 0;
2030 }
2031
2032 static int
2033 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2034 {
2035         int error;
2036         struct nfs_server *nfss = sb->s_fs_info;
2037         struct nfs_parsed_mount_data *data;
2038         struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2039         struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2040         u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2041
2042         /*
2043          * Userspace mount programs that send binary options generally send
2044          * them populated with default values. We have no way to know which
2045          * ones were explicitly specified. Fall back to legacy behavior and
2046          * just return success.
2047          */
2048         if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2049             (nfsvers <= 3 && (!options || (options->version >= 1 &&
2050                                            options->version <= 6))))
2051                 return 0;
2052
2053         data = kzalloc(sizeof(*data), GFP_KERNEL);
2054         if (data == NULL)
2055                 return -ENOMEM;
2056
2057         /* fill out struct with values from existing mount */
2058         data->flags = nfss->flags;
2059         data->rsize = nfss->rsize;
2060         data->wsize = nfss->wsize;
2061         data->retrans = nfss->client->cl_timeout->to_retries;
2062         data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2063         data->acregmin = nfss->acregmin / HZ;
2064         data->acregmax = nfss->acregmax / HZ;
2065         data->acdirmin = nfss->acdirmin / HZ;
2066         data->acdirmax = nfss->acdirmax / HZ;
2067         data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2068         data->nfs_server.port = nfss->port;
2069         data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2070         memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2071                 data->nfs_server.addrlen);
2072
2073         /* overwrite those values with any that were specified */
2074         error = nfs_parse_mount_options((char *)options, data);
2075         if (error < 0)
2076                 goto out;
2077
2078         /* compare new mount options with old ones */
2079         error = nfs_compare_remount_data(nfss, data);
2080 out:
2081         kfree(data);
2082         return error;
2083 }
2084
2085 /*
2086  * Initialise the common bits of the superblock
2087  */
2088 static inline void nfs_initialise_sb(struct super_block *sb)
2089 {
2090         struct nfs_server *server = NFS_SB(sb);
2091
2092         sb->s_magic = NFS_SUPER_MAGIC;
2093
2094         /* We probably want something more informative here */
2095         snprintf(sb->s_id, sizeof(sb->s_id),
2096                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2097
2098         if (sb->s_blocksize == 0)
2099                 sb->s_blocksize = nfs_block_bits(server->wsize,
2100                                                  &sb->s_blocksize_bits);
2101
2102         if (server->flags & NFS_MOUNT_NOAC)
2103                 sb->s_flags |= MS_SYNCHRONOUS;
2104
2105         sb->s_bdi = &server->backing_dev_info;
2106
2107         nfs_super_set_maxbytes(sb, server->maxfilesize);
2108 }
2109
2110 /*
2111  * Finish setting up an NFS2/3 superblock
2112  */
2113 static void nfs_fill_super(struct super_block *sb,
2114                            struct nfs_parsed_mount_data *data)
2115 {
2116         struct nfs_server *server = NFS_SB(sb);
2117
2118         sb->s_blocksize_bits = 0;
2119         sb->s_blocksize = 0;
2120         if (data->bsize)
2121                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2122
2123         if (server->nfs_client->rpc_ops->version == 3) {
2124                 /* The VFS shouldn't apply the umask to mode bits. We will do
2125                  * so ourselves when necessary.
2126                  */
2127                 sb->s_flags |= MS_POSIXACL;
2128                 sb->s_time_gran = 1;
2129         }
2130
2131         sb->s_op = &nfs_sops;
2132         nfs_initialise_sb(sb);
2133 }
2134
2135 /*
2136  * Finish setting up a cloned NFS2/3 superblock
2137  */
2138 static void nfs_clone_super(struct super_block *sb,
2139                             const struct super_block *old_sb)
2140 {
2141         struct nfs_server *server = NFS_SB(sb);
2142
2143         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2144         sb->s_blocksize = old_sb->s_blocksize;
2145         sb->s_maxbytes = old_sb->s_maxbytes;
2146
2147         if (server->nfs_client->rpc_ops->version == 3) {
2148                 /* The VFS shouldn't apply the umask to mode bits. We will do
2149                  * so ourselves when necessary.
2150                  */
2151                 sb->s_flags |= MS_POSIXACL;
2152                 sb->s_time_gran = 1;
2153         }
2154
2155         sb->s_op = old_sb->s_op;
2156         nfs_initialise_sb(sb);
2157 }
2158
2159 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2160 {
2161         const struct nfs_server *a = s->s_fs_info;
2162         const struct rpc_clnt *clnt_a = a->client;
2163         const struct rpc_clnt *clnt_b = b->client;
2164
2165         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2166                 goto Ebusy;
2167         if (a->nfs_client != b->nfs_client)
2168                 goto Ebusy;
2169         if (a->flags != b->flags)
2170                 goto Ebusy;
2171         if (a->wsize != b->wsize)
2172                 goto Ebusy;
2173         if (a->rsize != b->rsize)
2174                 goto Ebusy;
2175         if (a->acregmin != b->acregmin)
2176                 goto Ebusy;
2177         if (a->acregmax != b->acregmax)
2178                 goto Ebusy;
2179         if (a->acdirmin != b->acdirmin)
2180                 goto Ebusy;
2181         if (a->acdirmax != b->acdirmax)
2182                 goto Ebusy;
2183         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2184                 goto Ebusy;
2185         return 1;
2186 Ebusy:
2187         return 0;
2188 }
2189
2190 struct nfs_sb_mountdata {
2191         struct nfs_server *server;
2192         int mntflags;
2193 };
2194
2195 static int nfs_set_super(struct super_block *s, void *data)
2196 {
2197         struct nfs_sb_mountdata *sb_mntdata = data;
2198         struct nfs_server *server = sb_mntdata->server;
2199         int ret;
2200
2201         s->s_flags = sb_mntdata->mntflags;
2202         s->s_fs_info = server;
2203         ret = set_anon_super(s, server);
2204         if (ret == 0)
2205                 server->s_dev = s->s_dev;
2206         return ret;
2207 }
2208
2209 static int nfs_compare_super_address(struct nfs_server *server1,
2210                                      struct nfs_server *server2)
2211 {
2212         struct sockaddr *sap1, *sap2;
2213
2214         sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2215         sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2216
2217         if (sap1->sa_family != sap2->sa_family)
2218                 return 0;
2219
2220         switch (sap1->sa_family) {
2221         case AF_INET: {
2222                 struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2223                 struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2224                 if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2225                         return 0;
2226                 if (sin1->sin_port != sin2->sin_port)
2227                         return 0;
2228                 break;
2229         }
2230         case AF_INET6: {
2231                 struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2232                 struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2233                 if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2234                         return 0;
2235                 if (sin1->sin6_port != sin2->sin6_port)
2236                         return 0;
2237                 break;
2238         }
2239         default:
2240                 return 0;
2241         }
2242
2243         return 1;
2244 }
2245
2246 static int nfs_compare_super(struct super_block *sb, void *data)
2247 {
2248         struct nfs_sb_mountdata *sb_mntdata = data;
2249         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2250         int mntflags = sb_mntdata->mntflags;
2251
2252         if (!nfs_compare_super_address(old, server))
2253                 return 0;
2254         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2255         if (old->flags & NFS_MOUNT_UNSHARED)
2256                 return 0;
2257         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2258                 return 0;
2259         return nfs_compare_mount_options(sb, server, mntflags);
2260 }
2261
2262 static int nfs_bdi_register(struct nfs_server *server)
2263 {
2264         return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2265 }
2266
2267 static int nfs_get_sb(struct file_system_type *fs_type,
2268         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2269 {
2270         struct nfs_server *server = NULL;
2271         struct super_block *s;
2272         struct nfs_parsed_mount_data *data;
2273         struct nfs_fh *mntfh;
2274         struct dentry *mntroot;
2275         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2276         struct nfs_sb_mountdata sb_mntdata = {
2277                 .mntflags = flags,
2278         };
2279         int error = -ENOMEM;
2280
2281         data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
2282         mntfh = nfs_alloc_fhandle();
2283         if (data == NULL || mntfh == NULL)
2284                 goto out_free_fh;
2285
2286         security_init_mnt_opts(&data->lsm_opts);
2287
2288         /* Validate the mount data */
2289         error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2290         if (error < 0)
2291                 goto out;
2292
2293 #ifdef CONFIG_NFS_V4
2294         if (data->version == 4) {
2295                 error = nfs4_try_mount(flags, dev_name, data, mnt);
2296                 kfree(data->client_address);
2297                 kfree(data->nfs_server.export_path);
2298                 goto out;
2299         }
2300 #endif  /* CONFIG_NFS_V4 */
2301
2302         /* Get a volume representation */
2303         server = nfs_create_server(data, mntfh);
2304         if (IS_ERR(server)) {
2305                 error = PTR_ERR(server);
2306                 goto out;
2307         }
2308         sb_mntdata.server = server;
2309
2310         if (server->flags & NFS_MOUNT_UNSHARED)
2311                 compare_super = NULL;
2312
2313         /* Get a superblock - note that we may end up sharing one that already exists */
2314         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2315         if (IS_ERR(s)) {
2316                 error = PTR_ERR(s);
2317                 goto out_err_nosb;
2318         }
2319
2320         if (s->s_fs_info != server) {
2321                 nfs_free_server(server);
2322                 server = NULL;
2323         } else {
2324                 error = nfs_bdi_register(server);
2325                 if (error)
2326                         goto error_splat_bdi;
2327         }
2328
2329         if (!s->s_root) {
2330                 /* initial superblock/root creation */
2331                 nfs_fill_super(s, data);
2332                 nfs_fscache_get_super_cookie(
2333                         s, data ? data->fscache_uniq : NULL, NULL);
2334         }
2335
2336         mntroot = nfs_get_root(s, mntfh);
2337         if (IS_ERR(mntroot)) {
2338                 error = PTR_ERR(mntroot);
2339                 goto error_splat_super;
2340         }
2341
2342         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2343         if (error)
2344                 goto error_splat_root;
2345
2346         s->s_flags |= MS_ACTIVE;
2347         mnt->mnt_sb = s;
2348         mnt->mnt_root = mntroot;
2349         error = 0;
2350
2351 out:
2352         kfree(data->nfs_server.hostname);
2353         kfree(data->mount_server.hostname);
2354         kfree(data->fscache_uniq);
2355         security_free_mnt_opts(&data->lsm_opts);
2356 out_free_fh:
2357         nfs_free_fhandle(mntfh);
2358         kfree(data);
2359         return error;
2360
2361 out_err_nosb:
2362         nfs_free_server(server);
2363         goto out;
2364
2365 error_splat_root:
2366         dput(mntroot);
2367 error_splat_super:
2368         if (server && !s->s_root)
2369                 bdi_unregister(&server->backing_dev_info);
2370 error_splat_bdi:
2371         deactivate_locked_super(s);
2372         goto out;
2373 }
2374
2375 /*
2376  * Ensure that we unregister the bdi before kill_anon_super
2377  * releases the device name
2378  */
2379 static void nfs_put_super(struct super_block *s)
2380 {
2381         struct nfs_server *server = NFS_SB(s);
2382
2383         bdi_unregister(&server->backing_dev_info);
2384 }
2385
2386 /*
2387  * Destroy an NFS2/3 superblock
2388  */
2389 static void nfs_kill_super(struct super_block *s)
2390 {
2391         struct nfs_server *server = NFS_SB(s);
2392
2393         kill_anon_super(s);
2394         nfs_fscache_release_super_cookie(s);
2395         nfs_free_server(server);
2396 }
2397
2398 /*
2399  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2400  */
2401 static struct dentry *
2402 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2403                 const char *dev_name, void *raw_data)
2404 {
2405         struct nfs_clone_mount *data = raw_data;
2406         struct super_block *s;
2407         struct nfs_server *server;
2408         struct dentry *mntroot;
2409         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2410         struct nfs_sb_mountdata sb_mntdata = {
2411                 .mntflags = flags,
2412         };
2413         int error;
2414
2415         dprintk("--> nfs_xdev_mount()\n");
2416
2417         /* create a new volume representation */
2418         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2419         if (IS_ERR(server)) {
2420                 error = PTR_ERR(server);
2421                 goto out_err_noserver;
2422         }
2423         sb_mntdata.server = server;
2424
2425         if (server->flags & NFS_MOUNT_UNSHARED)
2426                 compare_super = NULL;
2427
2428         /* Get a superblock - note that we may end up sharing one that already exists */
2429         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2430         if (IS_ERR(s)) {
2431                 error = PTR_ERR(s);
2432                 goto out_err_nosb;
2433         }
2434
2435         if (s->s_fs_info != server) {
2436                 nfs_free_server(server);
2437                 server = NULL;
2438         } else {
2439                 error = nfs_bdi_register(server);
2440                 if (error)
2441                         goto error_splat_bdi;
2442         }
2443
2444         if (!s->s_root) {
2445                 /* initial superblock/root creation */
2446                 nfs_clone_super(s, data->sb);
2447                 nfs_fscache_get_super_cookie(s, NULL, data);
2448         }
2449
2450         mntroot = nfs_get_root(s, data->fh);
2451         if (IS_ERR(mntroot)) {
2452                 error = PTR_ERR(mntroot);
2453                 goto error_splat_super;
2454         }
2455         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2456                 dput(mntroot);
2457                 error = -ESTALE;
2458                 goto error_splat_super;
2459         }
2460
2461         s->s_flags |= MS_ACTIVE;
2462
2463         /* clone any lsm security options from the parent to the new sb */
2464         security_sb_clone_mnt_opts(data->sb, s);
2465
2466         dprintk("<-- nfs_xdev_mount() = 0\n");
2467         return mntroot;
2468
2469 out_err_nosb:
2470         nfs_free_server(server);
2471 out_err_noserver:
2472         dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2473         return ERR_PTR(error);
2474
2475 error_splat_super:
2476         if (server && !s->s_root)
2477                 bdi_unregister(&server->backing_dev_info);
2478 error_splat_bdi:
2479         deactivate_locked_super(s);
2480         dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2481         return ERR_PTR(error);
2482 }
2483
2484 #ifdef CONFIG_NFS_V4
2485
2486 /*
2487  * Finish setting up a cloned NFS4 superblock
2488  */
2489 static void nfs4_clone_super(struct super_block *sb,
2490                             const struct super_block *old_sb)
2491 {
2492         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2493         sb->s_blocksize = old_sb->s_blocksize;
2494         sb->s_maxbytes = old_sb->s_maxbytes;
2495         sb->s_time_gran = 1;
2496         sb->s_op = old_sb->s_op;
2497         nfs_initialise_sb(sb);
2498 }
2499
2500 /*
2501  * Set up an NFS4 superblock
2502  */
2503 static void nfs4_fill_super(struct super_block *sb)
2504 {
2505         sb->s_time_gran = 1;
2506         sb->s_op = &nfs4_sops;
2507         nfs_initialise_sb(sb);
2508 }
2509
2510 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2511 {
2512         args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2513                          NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2514 }
2515
2516 static int nfs4_validate_text_mount_data(void *options,
2517                                          struct nfs_parsed_mount_data *args,
2518                                          const char *dev_name)
2519 {
2520         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2521
2522         nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2523
2524         nfs_validate_transport_protocol(args);
2525
2526         nfs4_validate_mount_flags(args);
2527
2528         if (args->version != 4) {
2529                 dfprintk(MOUNT,
2530                          "NFS4: Illegal mount version\n");
2531                 return -EINVAL;
2532         }
2533
2534         if (args->auth_flavor_len > 1) {
2535                 dfprintk(MOUNT,
2536                          "NFS4: Too many RPC auth flavours specified\n");
2537                 return -EINVAL;
2538         }
2539
2540         if (args->client_address == NULL) {
2541                 dfprintk(MOUNT,
2542                          "NFS4: mount program didn't pass callback address\n");
2543                 return -EINVAL;
2544         }
2545
2546         return nfs_parse_devname(dev_name,
2547                                    &args->nfs_server.hostname,
2548                                    NFS4_MAXNAMLEN,
2549                                    &args->nfs_server.export_path,
2550                                    NFS4_MAXPATHLEN);
2551 }
2552
2553 /*
2554  * Validate NFSv4 mount options
2555  */
2556 static int nfs4_validate_mount_data(void *options,
2557                                     struct nfs_parsed_mount_data *args,
2558                                     const char *dev_name)
2559 {
2560         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2561         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2562         char *c;
2563
2564         if (data == NULL)
2565                 goto out_no_data;
2566
2567         switch (data->version) {
2568         case 1:
2569                 if (data->host_addrlen > sizeof(args->nfs_server.address))
2570                         goto out_no_address;
2571                 if (data->host_addrlen == 0)
2572                         goto out_no_address;
2573                 args->nfs_server.addrlen = data->host_addrlen;
2574                 if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2575                         return -EFAULT;
2576                 if (!nfs_verify_server_address(sap))
2577                         goto out_no_address;
2578
2579                 if (data->auth_flavourlen) {
2580                         if (data->auth_flavourlen > 1)
2581                                 goto out_inval_auth;
2582                         if (copy_from_user(&args->auth_flavors[0],
2583                                            data->auth_flavours,
2584                                            sizeof(args->auth_flavors[0])))
2585                                 return -EFAULT;
2586                 }
2587
2588                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2589                 if (IS_ERR(c))
2590                         return PTR_ERR(c);
2591                 args->nfs_server.hostname = c;
2592
2593                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2594                 if (IS_ERR(c))
2595                         return PTR_ERR(c);
2596                 args->nfs_server.export_path = c;
2597                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2598
2599                 c = strndup_user(data->client_addr.data, 16);
2600                 if (IS_ERR(c))
2601                         return PTR_ERR(c);
2602                 args->client_address = c;
2603
2604                 /*
2605                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2606                  * can deal with.
2607                  */
2608
2609                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
2610                 args->rsize     = data->rsize;
2611                 args->wsize     = data->wsize;
2612                 args->timeo     = data->timeo;
2613                 args->retrans   = data->retrans;
2614                 args->acregmin  = data->acregmin;
2615                 args->acregmax  = data->acregmax;
2616                 args->acdirmin  = data->acdirmin;
2617                 args->acdirmax  = data->acdirmax;
2618                 args->nfs_server.protocol = data->proto;
2619                 nfs_validate_transport_protocol(args);
2620
2621                 break;
2622         default:
2623                 if (nfs_parse_mount_options((char *)options, args) == 0)
2624                         return -EINVAL;
2625
2626                 if (!nfs_verify_server_address(sap))
2627                         return -EINVAL;
2628
2629                 return nfs4_validate_text_mount_data(options, args, dev_name);
2630         }
2631
2632         return 0;
2633
2634 out_no_data:
2635         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2636         return -EINVAL;
2637
2638 out_inval_auth:
2639         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2640                  data->auth_flavourlen);
2641         return -EINVAL;
2642
2643 out_no_address:
2644         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2645         return -EINVAL;
2646 }
2647
2648 /*
2649  * Get the superblock for the NFS4 root partition
2650  */
2651 static struct dentry *
2652 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2653                   const char *dev_name, void *raw_data)
2654 {
2655         struct nfs_parsed_mount_data *data = raw_data;
2656         struct super_block *s;
2657         struct nfs_server *server;
2658         struct nfs_fh *mntfh;
2659         struct dentry *mntroot;
2660         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2661         struct nfs_sb_mountdata sb_mntdata = {
2662                 .mntflags = flags,
2663         };
2664         int error = -ENOMEM;
2665
2666         mntfh = nfs_alloc_fhandle();
2667         if (data == NULL || mntfh == NULL)
2668                 goto out_free_fh;
2669
2670         security_init_mnt_opts(&data->lsm_opts);
2671
2672         /* Get a volume representation */
2673         server = nfs4_create_server(data, mntfh);
2674         if (IS_ERR(server)) {
2675                 error = PTR_ERR(server);
2676                 goto out;
2677         }
2678         sb_mntdata.server = server;
2679
2680         if (server->flags & NFS4_MOUNT_UNSHARED)
2681                 compare_super = NULL;
2682
2683         /* Get a superblock - note that we may end up sharing one that already exists */
2684         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2685         if (IS_ERR(s)) {
2686                 error = PTR_ERR(s);
2687                 goto out_free;
2688         }
2689
2690         if (s->s_fs_info != server) {
2691                 nfs_free_server(server);
2692                 server = NULL;
2693         } else {
2694                 error = nfs_bdi_register(server);
2695                 if (error)
2696                         goto error_splat_bdi;
2697         }
2698
2699         if (!s->s_root) {
2700                 /* initial superblock/root creation */
2701                 nfs4_fill_super(s);
2702                 nfs_fscache_get_super_cookie(
2703                         s, data ? data->fscache_uniq : NULL, NULL);
2704         }
2705
2706         mntroot = nfs4_get_root(s, mntfh);
2707         if (IS_ERR(mntroot)) {
2708                 error = PTR_ERR(mntroot);
2709                 goto error_splat_super;
2710         }
2711
2712         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2713         if (error)
2714                 goto error_splat_root;
2715
2716         s->s_flags |= MS_ACTIVE;
2717
2718         security_free_mnt_opts(&data->lsm_opts);
2719         nfs_free_fhandle(mntfh);
2720         return mntroot;
2721
2722 out:
2723         security_free_mnt_opts(&data->lsm_opts);
2724 out_free_fh:
2725         nfs_free_fhandle(mntfh);
2726         return ERR_PTR(error);
2727
2728 out_free:
2729         nfs_free_server(server);
2730         goto out;
2731
2732 error_splat_root:
2733         dput(mntroot);
2734 error_splat_super:
2735         if (server && !s->s_root)
2736                 bdi_unregister(&server->backing_dev_info);
2737 error_splat_bdi:
2738         deactivate_locked_super(s);
2739         goto out;
2740 }
2741
2742 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2743                 int flags, void *data, const char *hostname)
2744 {
2745         struct vfsmount *root_mnt;
2746         char *root_devname;
2747         size_t len;
2748
2749         len = strlen(hostname) + 3;
2750         root_devname = kmalloc(len, GFP_KERNEL);
2751         if (root_devname == NULL)
2752                 return ERR_PTR(-ENOMEM);
2753         snprintf(root_devname, len, "%s:/", hostname);
2754         root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2755         kfree(root_devname);
2756         return root_mnt;
2757 }
2758
2759 static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
2760 {
2761         char *page = (char *) __get_free_page(GFP_KERNEL);
2762         char *devname, *tmp;
2763
2764         if (page == NULL)
2765                 return;
2766         devname = nfs_path(path->mnt->mnt_devname,
2767                         path->mnt->mnt_root, path->dentry,
2768                         page, PAGE_SIZE);
2769         if (IS_ERR(devname))
2770                 goto out_freepage;
2771         tmp = kstrdup(devname, GFP_KERNEL);
2772         if (tmp == NULL)
2773                 goto out_freepage;
2774         kfree(mnt->mnt_devname);
2775         mnt->mnt_devname = tmp;
2776 out_freepage:
2777         free_page((unsigned long)page);
2778 }
2779
2780 struct nfs_referral_count {
2781         struct list_head list;
2782         const struct task_struct *task;
2783         unsigned int referral_count;
2784 };
2785
2786 static LIST_HEAD(nfs_referral_count_list);
2787 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2788
2789 static struct nfs_referral_count *nfs_find_referral_count(void)
2790 {
2791         struct nfs_referral_count *p;
2792
2793         list_for_each_entry(p, &nfs_referral_count_list, list) {
2794                 if (p->task == current)
2795                         return p;
2796         }
2797         return NULL;
2798 }
2799
2800 #define NFS_MAX_NESTED_REFERRALS 2
2801
2802 static int nfs_referral_loop_protect(void)
2803 {
2804         struct nfs_referral_count *p, *new;
2805         int ret = -ENOMEM;
2806
2807         new = kmalloc(sizeof(*new), GFP_KERNEL);
2808         if (!new)
2809                 goto out;
2810         new->task = current;
2811         new->referral_count = 1;
2812
2813         ret = 0;
2814         spin_lock(&nfs_referral_count_list_lock);
2815         p = nfs_find_referral_count();
2816         if (p != NULL) {
2817                 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2818                         ret = -ELOOP;
2819                 else
2820                         p->referral_count++;
2821         } else {
2822                 list_add(&new->list, &nfs_referral_count_list);
2823                 new = NULL;
2824         }
2825         spin_unlock(&nfs_referral_count_list_lock);
2826         kfree(new);
2827 out:
2828         return ret;
2829 }
2830
2831 static void nfs_referral_loop_unprotect(void)
2832 {
2833         struct nfs_referral_count *p;
2834
2835         spin_lock(&nfs_referral_count_list_lock);
2836         p = nfs_find_referral_count();
2837         p->referral_count--;
2838         if (p->referral_count == 0)
2839                 list_del(&p->list);
2840         else
2841                 p = NULL;
2842         spin_unlock(&nfs_referral_count_list_lock);
2843         kfree(p);
2844 }
2845
2846 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
2847                 const char *export_path, struct vfsmount *mnt_target)
2848 {
2849         struct nameidata *nd = NULL;
2850         struct mnt_namespace *ns_private;
2851         struct super_block *s;
2852         int ret;
2853
2854         nd = kmalloc(sizeof(*nd), GFP_KERNEL);
2855         if (nd == NULL)
2856                 return -ENOMEM;
2857
2858         ns_private = create_mnt_ns(root_mnt);
2859         ret = PTR_ERR(ns_private);
2860         if (IS_ERR(ns_private))
2861                 goto out_mntput;
2862
2863         ret = nfs_referral_loop_protect();
2864         if (ret != 0)
2865                 goto out_put_mnt_ns;
2866
2867         ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
2868                         export_path, LOOKUP_FOLLOW, nd);
2869
2870         nfs_referral_loop_unprotect();
2871         put_mnt_ns(ns_private);
2872
2873         if (ret != 0)
2874                 goto out_err;
2875
2876         s = nd->path.mnt->mnt_sb;
2877         atomic_inc(&s->s_active);
2878         mnt_target->mnt_sb = s;
2879         mnt_target->mnt_root = dget(nd->path.dentry);
2880
2881         /* Correct the device pathname */
2882         nfs_fix_devname(&nd->path, mnt_target);
2883
2884         path_put(&nd->path);
2885         kfree(nd);
2886         down_write(&s->s_umount);
2887         return 0;
2888 out_put_mnt_ns:
2889         put_mnt_ns(ns_private);
2890 out_mntput:
2891         mntput(root_mnt);
2892 out_err:
2893         kfree(nd);
2894         return ret;
2895 }
2896
2897 static int nfs4_try_mount(int flags, const char *dev_name,
2898                          struct nfs_parsed_mount_data *data,
2899                          struct vfsmount *mnt)
2900 {
2901         char *export_path;
2902         struct vfsmount *root_mnt;
2903         int error;
2904
2905         dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2906
2907         export_path = data->nfs_server.export_path;
2908         data->nfs_server.export_path = "/";
2909         root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2910                         data->nfs_server.hostname);
2911         data->nfs_server.export_path = export_path;
2912
2913         error = PTR_ERR(root_mnt);
2914         if (IS_ERR(root_mnt))
2915                 goto out;
2916
2917         error = nfs_follow_remote_path(root_mnt, export_path, mnt);
2918
2919 out:
2920         dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
2921                         error != 0 ? " [error]" : "");
2922         return error;
2923 }
2924
2925 /*
2926  * Get the superblock for an NFS4 mountpoint
2927  */
2928 static int nfs4_get_sb(struct file_system_type *fs_type,
2929         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2930 {
2931         struct nfs_parsed_mount_data *data;
2932         int error = -ENOMEM;
2933
2934         data = nfs_alloc_parsed_mount_data(4);
2935         if (data == NULL)
2936                 goto out_free_data;
2937
2938         /* Validate the mount data */
2939         error = nfs4_validate_mount_data(raw_data, data, dev_name);
2940         if (error < 0)
2941                 goto out;
2942
2943         error = nfs4_try_mount(flags, dev_name, data, mnt);
2944
2945 out:
2946         kfree(data->client_address);
2947         kfree(data->nfs_server.export_path);
2948         kfree(data->nfs_server.hostname);
2949         kfree(data->fscache_uniq);
2950 out_free_data:
2951         kfree(data);
2952         dprintk("<-- nfs4_get_sb() = %d%s\n", error,
2953                         error != 0 ? " [error]" : "");
2954         return error;
2955 }
2956
2957 static void nfs4_kill_super(struct super_block *sb)
2958 {
2959         struct nfs_server *server = NFS_SB(sb);
2960
2961         dprintk("--> %s\n", __func__);
2962         nfs_super_return_all_delegations(sb);
2963         kill_anon_super(sb);
2964         nfs_fscache_release_super_cookie(sb);
2965         nfs_free_server(server);
2966         dprintk("<-- %s\n", __func__);
2967 }
2968
2969 /*
2970  * Clone an NFS4 server record on xdev traversal (FSID-change)
2971  */
2972 static struct dentry *
2973 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2974                  const char *dev_name, void *raw_data)
2975 {
2976         struct nfs_clone_mount *data = raw_data;
2977         struct super_block *s;
2978         struct nfs_server *server;
2979         struct dentry *mntroot;
2980         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2981         struct nfs_sb_mountdata sb_mntdata = {
2982                 .mntflags = flags,
2983         };
2984         int error;
2985
2986         dprintk("--> nfs4_xdev_mount()\n");
2987
2988         /* create a new volume representation */
2989         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2990         if (IS_ERR(server)) {
2991                 error = PTR_ERR(server);
2992                 goto out_err_noserver;
2993         }
2994         sb_mntdata.server = server;
2995
2996         if (server->flags & NFS4_MOUNT_UNSHARED)
2997                 compare_super = NULL;
2998
2999         /* Get a superblock - note that we may end up sharing one that already exists */
3000         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3001         if (IS_ERR(s)) {
3002                 error = PTR_ERR(s);
3003                 goto out_err_nosb;
3004         }
3005
3006         if (s->s_fs_info != server) {
3007                 nfs_free_server(server);
3008                 server = NULL;
3009         } else {
3010                 error = nfs_bdi_register(server);
3011                 if (error)
3012                         goto error_splat_bdi;
3013         }
3014
3015         if (!s->s_root) {
3016                 /* initial superblock/root creation */
3017                 nfs4_clone_super(s, data->sb);
3018                 nfs_fscache_get_super_cookie(s, NULL, data);
3019         }
3020
3021         mntroot = nfs4_get_root(s, data->fh);
3022         if (IS_ERR(mntroot)) {
3023                 error = PTR_ERR(mntroot);
3024                 goto error_splat_super;
3025         }
3026         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3027                 dput(mntroot);
3028                 error = -ESTALE;
3029                 goto error_splat_super;
3030         }
3031
3032         s->s_flags |= MS_ACTIVE;
3033
3034         security_sb_clone_mnt_opts(data->sb, s);
3035
3036         dprintk("<-- nfs4_xdev_mount() = 0\n");
3037         return mntroot;
3038
3039 out_err_nosb:
3040         nfs_free_server(server);
3041 out_err_noserver:
3042         dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3043         return ERR_PTR(error);
3044
3045 error_splat_super:
3046         if (server && !s->s_root)
3047                 bdi_unregister(&server->backing_dev_info);
3048 error_splat_bdi:
3049         deactivate_locked_super(s);
3050         dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3051         return ERR_PTR(error);
3052 }
3053
3054 static struct dentry *
3055 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3056                            const char *dev_name, void *raw_data)
3057 {
3058         struct nfs_clone_mount *data = raw_data;
3059         struct super_block *s;
3060         struct nfs_server *server;
3061         struct dentry *mntroot;
3062         struct nfs_fh *mntfh;
3063         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3064         struct nfs_sb_mountdata sb_mntdata = {
3065                 .mntflags = flags,
3066         };
3067         int error = -ENOMEM;
3068
3069         dprintk("--> nfs4_referral_get_sb()\n");
3070
3071         mntfh = nfs_alloc_fhandle();
3072         if (mntfh == NULL)
3073                 goto out_err_nofh;
3074
3075         /* create a new volume representation */
3076         server = nfs4_create_referral_server(data, mntfh);
3077         if (IS_ERR(server)) {
3078                 error = PTR_ERR(server);
3079                 goto out_err_noserver;
3080         }
3081         sb_mntdata.server = server;
3082
3083         if (server->flags & NFS4_MOUNT_UNSHARED)
3084                 compare_super = NULL;
3085
3086         /* Get a superblock - note that we may end up sharing one that already exists */
3087         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3088         if (IS_ERR(s)) {
3089                 error = PTR_ERR(s);
3090                 goto out_err_nosb;
3091         }
3092
3093         if (s->s_fs_info != server) {
3094                 nfs_free_server(server);
3095                 server = NULL;
3096         } else {
3097                 error = nfs_bdi_register(server);
3098                 if (error)
3099                         goto error_splat_bdi;
3100         }
3101
3102         if (!s->s_root) {
3103                 /* initial superblock/root creation */
3104                 nfs4_fill_super(s);
3105                 nfs_fscache_get_super_cookie(s, NULL, data);
3106         }
3107
3108         mntroot = nfs4_get_root(s, mntfh);
3109         if (IS_ERR(mntroot)) {
3110                 error = PTR_ERR(mntroot);
3111                 goto error_splat_super;
3112         }
3113         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3114                 dput(mntroot);
3115                 error = -ESTALE;
3116                 goto error_splat_super;
3117         }
3118
3119         s->s_flags |= MS_ACTIVE;
3120
3121         security_sb_clone_mnt_opts(data->sb, s);
3122
3123         nfs_free_fhandle(mntfh);
3124         dprintk("<-- nfs4_referral_get_sb() = 0\n");
3125         return mntroot;
3126
3127 out_err_nosb:
3128         nfs_free_server(server);
3129 out_err_noserver:
3130         nfs_free_fhandle(mntfh);
3131 out_err_nofh:
3132         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3133         return ERR_PTR(error);
3134
3135 error_splat_super:
3136         if (server && !s->s_root)
3137                 bdi_unregister(&server->backing_dev_info);
3138 error_splat_bdi:
3139         deactivate_locked_super(s);
3140         nfs_free_fhandle(mntfh);
3141         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3142         return ERR_PTR(error);
3143 }
3144
3145 /*
3146  * Create an NFS4 server record on referral traversal
3147  */
3148 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
3149                 int flags, const char *dev_name, void *raw_data,
3150                 struct vfsmount *mnt)
3151 {
3152         struct nfs_clone_mount *data = raw_data;
3153         char *export_path;
3154         struct vfsmount *root_mnt;
3155         int error;
3156
3157         dprintk("--> nfs4_referral_get_sb()\n");
3158
3159         export_path = data->mnt_path;
3160         data->mnt_path = "/";
3161
3162         root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3163                         flags, data, data->hostname);
3164         data->mnt_path = export_path;
3165
3166         error = PTR_ERR(root_mnt);
3167         if (IS_ERR(root_mnt))
3168                 goto out;
3169
3170         error = nfs_follow_remote_path(root_mnt, export_path, mnt);
3171 out:
3172         dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
3173                         error != 0 ? " [error]" : "");
3174         return error;
3175 }
3176
3177 #endif /* CONFIG_NFS_V4 */