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 &&
 602                 nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
 603                 showdefaults)
 604                 seq_printf(m, ",mountport=%u", nfss->mountd_port);
 605
 606         nfs_show_mountd_netid(m, nfss, showdefaults);
 607 }
 608
 609 #ifdef CONFIG_NFS_V4
 610 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
 611                                     int showdefaults)
 612 {
 613         struct nfs_client *clp = nfss->nfs_client;
 614
 615         seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
 616         seq_printf(m, ",minorversion=%u", clp->cl_minorversion);
 617 }
 618 #else
 619 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
 620                                     int showdefaults)
 621 {
 622 }
 623 #endif
 624
 625 /*
 626  * Describe the mount options in force on this server representation
 627  */
 628 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
 629                                    int showdefaults)
 630 {
 631         static const struct proc_nfs_info {
 632                 int flag;
 633                 const char *str;
 634                 const char *nostr;
 635         } nfs_info[] = {
 636                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 637                 { NFS_MOUNT_POSIX, ",posix", "" },
 638                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 639                 { NFS_MOUNT_NOAC, ",noac", "" },
 640                 { NFS_MOUNT_NONLM, ",nolock", "" },
 641                 { NFS_MOUNT_NOACL, ",noacl", "" },
 642                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 643                 { NFS_MOUNT_UNSHARED, ",nosharecache", "" },
 644                 { NFS_MOUNT_NORESVPORT, ",noresvport", "" },
 645                 { 0, NULL, NULL }
 646         };
 647         const struct proc_nfs_info *nfs_infop;
 648         struct nfs_client *clp = nfss->nfs_client;
 649         u32 version = clp->rpc_ops->version;
 650         int local_flock, local_fcntl;
 651
 652         seq_printf(m, ",vers=%u", version);
 653         seq_printf(m, ",rsize=%u", nfss->rsize);
 654         seq_printf(m, ",wsize=%u", nfss->wsize);
 655         if (nfss->bsize != 0)
 656                 seq_printf(m, ",bsize=%u", nfss->bsize);
 657         seq_printf(m, ",namlen=%u", nfss->namelen);
 658         if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
 659                 seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
 660         if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
 661                 seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
 662         if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
 663                 seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
 664         if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
 665                 seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
 666         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 667                 if (nfss->flags & nfs_infop->flag)
 668                         seq_puts(m, nfs_infop->str);
 669                 else
 670                         seq_puts(m, nfs_infop->nostr);
 671         }
 672         seq_printf(m, ",proto=%s",
 673                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
 674         if (version == 4) {
 675                 if (nfss->port != NFS_PORT)
 676                         seq_printf(m, ",port=%u", nfss->port);
 677         } else
 678                 if (nfss->port)
 679                         seq_printf(m, ",port=%u", nfss->port);
 680
 681         seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
 682         seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
 683         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 684
 685         if (version != 4)
 686                 nfs_show_mountd_options(m, nfss, showdefaults);
 687         else
 688                 nfs_show_nfsv4_options(m, nfss, showdefaults);
 689
 690         if (nfss->options & NFS_OPTION_FSCACHE)
 691                 seq_printf(m, ",fsc");
 692
 693         if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
 694                 if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
 695                         seq_printf(m, ",lookupcache=none");
 696                 else
 697                         seq_printf(m, ",lookupcache=pos");
 698         }
 699
 700         local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
 701         local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
 702
 703         if (!local_flock && !local_fcntl)
 704                 seq_printf(m, ",local_lock=none");
 705         else if (local_flock && local_fcntl)
 706                 seq_printf(m, ",local_lock=all");
 707         else if (local_flock)
 708                 seq_printf(m, ",local_lock=flock");
 709         else
 710                 seq_printf(m, ",local_lock=posix");
 711 }
 712
 713 /*
 714  * Describe the mount options on this VFS mountpoint
 715  */
 716 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 717 {
 718         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 719
 720         nfs_show_mount_options(m, nfss, 0);
 721
 722         seq_printf(m, ",addr=%s",
 723                         rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
 724                                                         RPC_DISPLAY_ADDR));
 725
 726         return 0;
 727 }
 728
 729 /*
 730  * Present statistical information for this VFS mountpoint
 731  */
 732 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 733 {
 734         int i, cpu;
 735         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 736         struct rpc_auth *auth = nfss->client->cl_auth;
 737         struct nfs_iostats totals = { };
 738
 739         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 740
 741         /*
 742          * Display all mount option settings
 743          */
 744         seq_printf(m, "\n\topts:\t");
 745         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 746         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 747         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 748         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 749         nfs_show_mount_options(m, nfss, 1);
 750
 751         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 752
 753         seq_printf(m, "\n\tcaps:\t");
 754         seq_printf(m, "caps=0x%x", nfss->caps);
 755         seq_printf(m, ",wtmult=%u", nfss->wtmult);
 756         seq_printf(m, ",dtsize=%u", nfss->dtsize);
 757         seq_printf(m, ",bsize=%u", nfss->bsize);
 758         seq_printf(m, ",namlen=%u", nfss->namelen);
 759
 760 #ifdef CONFIG_NFS_V4
 761         if (nfss->nfs_client->rpc_ops->version == 4) {
 762                 seq_printf(m, "\n\tnfsv4:\t");
 763                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 764                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 765                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 766         }
 767 #endif
 768
 769         /*
 770          * Display security flavor in effect for this mount
 771          */
 772         seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
 773         if (auth->au_flavor)
 774                 seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
 775
 776         /*
 777          * Display superblock I/O counters
 778          */
 779         for_each_possible_cpu(cpu) {
 780                 struct nfs_iostats *stats;
 781
 782                 preempt_disable();
 783                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 784
 785                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 786                         totals.events[i] += stats->events[i];
 787                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 788                         totals.bytes[i] += stats->bytes[i];
 789 #ifdef CONFIG_NFS_FSCACHE
 790                 for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
 791                         totals.fscache[i] += stats->fscache[i];
 792 #endif
 793
 794                 preempt_enable();
 795         }
 796
 797         seq_printf(m, "\n\tevents:\t");
 798         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 799                 seq_printf(m, "%lu ", totals.events[i]);
 800         seq_printf(m, "\n\tbytes:\t");
 801         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 802                 seq_printf(m, "%Lu ", totals.bytes[i]);
 803 #ifdef CONFIG_NFS_FSCACHE
 804         if (nfss->options & NFS_OPTION_FSCACHE) {
 805                 seq_printf(m, "\n\tfsc:\t");
 806                 for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
 807                         seq_printf(m, "%Lu ", totals.bytes[i]);
 808         }
 809 #endif
 810         seq_printf(m, "\n");
 811
 812         rpc_print_iostats(m, nfss->client);
 813
 814         return 0;
 815 }
 816
 817 /*
 818  * Begin unmount by attempting to remove all automounted mountpoints we added
 819  * in response to xdev traversals and referrals
 820  */
 821 static void nfs_umount_begin(struct super_block *sb)
 822 {
 823         struct nfs_server *server;
 824         struct rpc_clnt *rpc;
 825
 826         server = NFS_SB(sb);
 827         /* -EIO all pending I/O */
 828         rpc = server->client_acl;
 829         if (!IS_ERR(rpc))
 830                 rpc_killall_tasks(rpc);
 831         rpc = server->client;
 832         if (!IS_ERR(rpc))
 833                 rpc_killall_tasks(rpc);
 834 }
 835
 836 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
 837 {
 838         struct nfs_parsed_mount_data *data;
 839
 840         data = kzalloc(sizeof(*data), GFP_KERNEL);
 841         if (data) {
 842                 data->acregmin          = NFS_DEF_ACREGMIN;
 843                 data->acregmax          = NFS_DEF_ACREGMAX;
 844                 data->acdirmin          = NFS_DEF_ACDIRMIN;
 845                 data->acdirmax          = NFS_DEF_ACDIRMAX;
 846                 data->mount_server.port = NFS_UNSPEC_PORT;
 847                 data->nfs_server.port   = NFS_UNSPEC_PORT;
 848                 data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 849                 data->auth_flavors[0]   = RPC_AUTH_UNIX;
 850                 data->auth_flavor_len   = 1;
 851                 data->version           = version;
 852                 data->minorversion      = 0;
 853         }
 854         return data;
 855 }
 856
 857 /*
 858  * Sanity-check a server address provided by the mount command.
 859  *
 860  * Address family must be initialized, and address must not be
 861  * the ANY address for that family.
 862  */
 863 static int nfs_verify_server_address(struct sockaddr *addr)
 864 {
 865         switch (addr->sa_family) {
 866         case AF_INET: {
 867                 struct sockaddr_in *sa = (struct sockaddr_in *)addr;
 868                 return sa->sin_addr.s_addr != htonl(INADDR_ANY);
 869         }
 870         case AF_INET6: {
 871                 struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
 872                 return !ipv6_addr_any(sa);
 873         }
 874         }
 875
 876         dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
 877         return 0;
 878 }
 879
 880 /*
 881  * Select between a default port value and a user-specified port value.
 882  * If a zero value is set, then autobind will be used.
 883  */
 884 static void nfs_set_port(struct sockaddr *sap, int *port,
 885                                  const unsigned short default_port)
 886 {
 887         if (*port == NFS_UNSPEC_PORT)
 888                 *port = default_port;
 889
 890         rpc_set_port(sap, *port);
 891 }
 892
 893 /*
 894  * Sanity check the NFS transport protocol.
 895  *
 896  */
 897 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
 898 {
 899         switch (mnt->nfs_server.protocol) {
 900         case XPRT_TRANSPORT_UDP:
 901         case XPRT_TRANSPORT_TCP:
 902         case XPRT_TRANSPORT_RDMA:
 903                 break;
 904         default:
 905                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 906         }
 907 }
 908
 909 /*
 910  * For text based NFSv2/v3 mounts, the mount protocol transport default
 911  * settings should depend upon the specified NFS transport.
 912  */
 913 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
 914 {
 915         nfs_validate_transport_protocol(mnt);
 916
 917         if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
 918             mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
 919                         return;
 920         switch (mnt->nfs_server.protocol) {
 921         case XPRT_TRANSPORT_UDP:
 922                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 923                 break;
 924         case XPRT_TRANSPORT_TCP:
 925         case XPRT_TRANSPORT_RDMA:
 926                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 927         }
 928 }
 929
 930 /*
 931  * Parse the value of the 'sec=' option.
 932  */
 933 static int nfs_parse_security_flavors(char *value,
 934                                       struct nfs_parsed_mount_data *mnt)
 935 {
 936         substring_t args[MAX_OPT_ARGS];
 937
 938         dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
 939
 940         switch (match_token(value, nfs_secflavor_tokens, args)) {
 941         case Opt_sec_none:
 942                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 943                 break;
 944         case Opt_sec_sys:
 945                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 946                 break;
 947         case Opt_sec_krb5:
 948                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 949                 break;
 950         case Opt_sec_krb5i:
 951                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 952                 break;
 953         case Opt_sec_krb5p:
 954                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 955                 break;
 956         case Opt_sec_lkey:
 957                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 958                 break;
 959         case Opt_sec_lkeyi:
 960                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 961                 break;
 962         case Opt_sec_lkeyp:
 963                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 964                 break;
 965         case Opt_sec_spkm:
 966                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 967                 break;
 968         case Opt_sec_spkmi:
 969                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 970                 break;
 971         case Opt_sec_spkmp:
 972                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 973                 break;
 974         default:
 975                 return 0;
 976         }
 977
 978         mnt->auth_flavor_len = 1;
 979         return 1;
 980 }
 981
 982 /*
 983  * Error-check and convert a string of mount options from user space into
 984  * a data structure.  The whole mount string is processed; bad options are
 985  * skipped as they are encountered.  If there were no errors, return 1;
 986  * otherwise return 0 (zero).
 987  */
 988 static int nfs_parse_mount_options(char *raw,
 989                                    struct nfs_parsed_mount_data *mnt)
 990 {
 991         char *p, *string, *secdata;
 992         int rc, sloppy = 0, invalid_option = 0;
 993         unsigned short protofamily = AF_UNSPEC;
 994         unsigned short mountfamily = AF_UNSPEC;
 995
 996         if (!raw) {
 997                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 998                 return 1;
 999         }
1000         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
1001
1002         secdata = alloc_secdata();
1003         if (!secdata)
1004                 goto out_nomem;
1005
1006         rc = security_sb_copy_data(raw, secdata);
1007         if (rc)
1008                 goto out_security_failure;
1009
1010         rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1011         if (rc)
1012                 goto out_security_failure;
1013
1014         free_secdata(secdata);
1015
1016         while ((p = strsep(&raw, ",")) != NULL) {
1017                 substring_t args[MAX_OPT_ARGS];
1018                 unsigned long option;
1019                 int token;
1020
1021                 if (!*p)
1022                         continue;
1023
1024                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1025
1026                 token = match_token(p, nfs_mount_option_tokens, args);
1027                 switch (token) {
1028
1029                 /*
1030                  * boolean options:  foo/nofoo
1031                  */
1032                 case Opt_soft:
1033                         mnt->flags |= NFS_MOUNT_SOFT;
1034                         break;
1035                 case Opt_hard:
1036                         mnt->flags &= ~NFS_MOUNT_SOFT;
1037                         break;
1038                 case Opt_posix:
1039                         mnt->flags |= NFS_MOUNT_POSIX;
1040                         break;
1041                 case Opt_noposix:
1042                         mnt->flags &= ~NFS_MOUNT_POSIX;
1043                         break;
1044                 case Opt_cto:
1045                         mnt->flags &= ~NFS_MOUNT_NOCTO;
1046                         break;
1047                 case Opt_nocto:
1048                         mnt->flags |= NFS_MOUNT_NOCTO;
1049                         break;
1050                 case Opt_ac:
1051                         mnt->flags &= ~NFS_MOUNT_NOAC;
1052                         break;
1053                 case Opt_noac:
1054                         mnt->flags |= NFS_MOUNT_NOAC;
1055                         break;
1056                 case Opt_lock:
1057                         mnt->flags &= ~NFS_MOUNT_NONLM;
1058                         mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1059                                         NFS_MOUNT_LOCAL_FCNTL);
1060                         break;
1061                 case Opt_nolock:
1062                         mnt->flags |= NFS_MOUNT_NONLM;
1063                         mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1064                                        NFS_MOUNT_LOCAL_FCNTL);
1065                         break;
1066                 case Opt_v2:
1067                         mnt->flags &= ~NFS_MOUNT_VER3;
1068                         mnt->version = 2;
1069                         break;
1070                 case Opt_v3:
1071                         mnt->flags |= NFS_MOUNT_VER3;
1072                         mnt->version = 3;
1073                         break;
1074                 case Opt_v4:
1075                         mnt->flags &= ~NFS_MOUNT_VER3;
1076                         mnt->version = 4;
1077                         break;
1078                 case Opt_udp:
1079                         mnt->flags &= ~NFS_MOUNT_TCP;
1080                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1081                         break;
1082                 case Opt_tcp:
1083                         mnt->flags |= NFS_MOUNT_TCP;
1084                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1085                         break;
1086                 case Opt_rdma:
1087                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1088                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1089                         xprt_load_transport(p);
1090                         break;
1091                 case Opt_acl:
1092                         mnt->flags &= ~NFS_MOUNT_NOACL;
1093                         break;
1094                 case Opt_noacl:
1095                         mnt->flags |= NFS_MOUNT_NOACL;
1096                         break;
1097                 case Opt_rdirplus:
1098                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1099                         break;
1100                 case Opt_nordirplus:
1101                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1102                         break;
1103                 case Opt_sharecache:
1104                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
1105                         break;
1106                 case Opt_nosharecache:
1107                         mnt->flags |= NFS_MOUNT_UNSHARED;
1108                         break;
1109                 case Opt_resvport:
1110                         mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1111                         break;
1112                 case Opt_noresvport:
1113                         mnt->flags |= NFS_MOUNT_NORESVPORT;
1114                         break;
1115                 case Opt_fscache:
1116                         mnt->options |= NFS_OPTION_FSCACHE;
1117                         kfree(mnt->fscache_uniq);
1118                         mnt->fscache_uniq = NULL;
1119                         break;
1120                 case Opt_nofscache:
1121                         mnt->options &= ~NFS_OPTION_FSCACHE;
1122                         kfree(mnt->fscache_uniq);
1123                         mnt->fscache_uniq = NULL;
1124                         break;
1125
1126                 /*
1127                  * options that take numeric values
1128                  */
1129                 case Opt_port:
1130                         string = match_strdup(args);
1131                         if (string == NULL)
1132                                 goto out_nomem;
1133                         rc = strict_strtoul(string, 10, &option);
1134                         kfree(string);
1135                         if (rc != 0 || option > USHRT_MAX)
1136                                 goto out_invalid_value;
1137                         mnt->nfs_server.port = option;
1138                         break;
1139                 case Opt_rsize:
1140                         string = match_strdup(args);
1141                         if (string == NULL)
1142                                 goto out_nomem;
1143                         rc = strict_strtoul(string, 10, &option);
1144                         kfree(string);
1145                         if (rc != 0)
1146                                 goto out_invalid_value;
1147                         mnt->rsize = option;
1148                         break;
1149                 case Opt_wsize:
1150                         string = match_strdup(args);
1151                         if (string == NULL)
1152                                 goto out_nomem;
1153                         rc = strict_strtoul(string, 10, &option);
1154                         kfree(string);
1155                         if (rc != 0)
1156                                 goto out_invalid_value;
1157                         mnt->wsize = option;
1158                         break;
1159                 case Opt_bsize:
1160                         string = match_strdup(args);
1161                         if (string == NULL)
1162                                 goto out_nomem;
1163                         rc = strict_strtoul(string, 10, &option);
1164                         kfree(string);
1165                         if (rc != 0)
1166                                 goto out_invalid_value;
1167                         mnt->bsize = option;
1168                         break;
1169                 case Opt_timeo:
1170                         string = match_strdup(args);
1171                         if (string == NULL)
1172                                 goto out_nomem;
1173                         rc = strict_strtoul(string, 10, &option);
1174                         kfree(string);
1175                         if (rc != 0 || option == 0)
1176                                 goto out_invalid_value;
1177                         mnt->timeo = option;
1178                         break;
1179                 case Opt_retrans:
1180                         string = match_strdup(args);
1181                         if (string == NULL)
1182                                 goto out_nomem;
1183                         rc = strict_strtoul(string, 10, &option);
1184                         kfree(string);
1185                         if (rc != 0 || option == 0)
1186                                 goto out_invalid_value;
1187                         mnt->retrans = option;
1188                         break;
1189                 case Opt_acregmin:
1190                         string = match_strdup(args);
1191                         if (string == NULL)
1192                                 goto out_nomem;
1193                         rc = strict_strtoul(string, 10, &option);
1194                         kfree(string);
1195                         if (rc != 0)
1196                                 goto out_invalid_value;
1197                         mnt->acregmin = option;
1198                         break;
1199                 case Opt_acregmax:
1200                         string = match_strdup(args);
1201                         if (string == NULL)
1202                                 goto out_nomem;
1203                         rc = strict_strtoul(string, 10, &option);
1204                         kfree(string);
1205                         if (rc != 0)
1206                                 goto out_invalid_value;
1207                         mnt->acregmax = option;
1208                         break;
1209                 case Opt_acdirmin:
1210                         string = match_strdup(args);
1211                         if (string == NULL)
1212                                 goto out_nomem;
1213                         rc = strict_strtoul(string, 10, &option);
1214                         kfree(string);
1215                         if (rc != 0)
1216                                 goto out_invalid_value;
1217                         mnt->acdirmin = option;
1218                         break;
1219                 case Opt_acdirmax:
1220                         string = match_strdup(args);
1221                         if (string == NULL)
1222                                 goto out_nomem;
1223                         rc = strict_strtoul(string, 10, &option);
1224                         kfree(string);
1225                         if (rc != 0)
1226                                 goto out_invalid_value;
1227                         mnt->acdirmax = option;
1228                         break;
1229                 case Opt_actimeo:
1230                         string = match_strdup(args);
1231                         if (string == NULL)
1232                                 goto out_nomem;
1233                         rc = strict_strtoul(string, 10, &option);
1234                         kfree(string);
1235                         if (rc != 0)
1236                                 goto out_invalid_value;
1237                         mnt->acregmin = mnt->acregmax =
1238                         mnt->acdirmin = mnt->acdirmax = option;
1239                         break;
1240                 case Opt_namelen:
1241                         string = match_strdup(args);
1242                         if (string == NULL)
1243                                 goto out_nomem;
1244                         rc = strict_strtoul(string, 10, &option);
1245                         kfree(string);
1246                         if (rc != 0)
1247                                 goto out_invalid_value;
1248                         mnt->namlen = option;
1249                         break;
1250                 case Opt_mountport:
1251                         string = match_strdup(args);
1252                         if (string == NULL)
1253                                 goto out_nomem;
1254                         rc = strict_strtoul(string, 10, &option);
1255                         kfree(string);
1256                         if (rc != 0 || option > USHRT_MAX)
1257                                 goto out_invalid_value;
1258                         mnt->mount_server.port = option;
1259                         break;
1260                 case Opt_mountvers:
1261                         string = match_strdup(args);
1262                         if (string == NULL)
1263                                 goto out_nomem;
1264                         rc = strict_strtoul(string, 10, &option);
1265                         kfree(string);
1266                         if (rc != 0 ||
1267                             option < NFS_MNT_VERSION ||
1268                             option > NFS_MNT3_VERSION)
1269                                 goto out_invalid_value;
1270                         mnt->mount_server.version = option;
1271                         break;
1272                 case Opt_nfsvers:
1273                         string = match_strdup(args);
1274                         if (string == NULL)
1275                                 goto out_nomem;
1276                         rc = strict_strtoul(string, 10, &option);
1277                         kfree(string);
1278                         if (rc != 0)
1279                                 goto out_invalid_value;
1280                         switch (option) {
1281                         case NFS2_VERSION:
1282                                 mnt->flags &= ~NFS_MOUNT_VER3;
1283                                 mnt->version = 2;
1284                                 break;
1285                         case NFS3_VERSION:
1286                                 mnt->flags |= NFS_MOUNT_VER3;
1287                                 mnt->version = 3;
1288                                 break;
1289                         case NFS4_VERSION:
1290                                 mnt->flags &= ~NFS_MOUNT_VER3;
1291                                 mnt->version = 4;
1292                                 break;
1293                         default:
1294                                 goto out_invalid_value;
1295                         }
1296                         break;
1297                 case Opt_minorversion:
1298                         string = match_strdup(args);
1299                         if (string == NULL)
1300                                 goto out_nomem;
1301                         rc = strict_strtoul(string, 10, &option);
1302                         kfree(string);
1303                         if (rc != 0)
1304                                 goto out_invalid_value;
1305                         if (option > NFS4_MAX_MINOR_VERSION)
1306                                 goto out_invalid_value;
1307                         mnt->minorversion = option;
1308                         break;
1309
1310                 /*
1311                  * options that take text values
1312                  */
1313                 case Opt_sec:
1314                         string = match_strdup(args);
1315                         if (string == NULL)
1316                                 goto out_nomem;
1317                         rc = nfs_parse_security_flavors(string, mnt);
1318                         kfree(string);
1319                         if (!rc) {
1320                                 dfprintk(MOUNT, "NFS:   unrecognized "
1321                                                 "security flavor\n");
1322                                 return 0;
1323                         }
1324                         break;
1325                 case Opt_proto:
1326                         string = match_strdup(args);
1327                         if (string == NULL)
1328                                 goto out_nomem;
1329                         token = match_token(string,
1330                                             nfs_xprt_protocol_tokens, args);
1331
1332                         protofamily = AF_INET;
1333                         switch (token) {
1334                         case Opt_xprt_udp6:
1335                                 protofamily = AF_INET6;
1336                         case Opt_xprt_udp:
1337                                 mnt->flags &= ~NFS_MOUNT_TCP;
1338                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1339                                 kfree(string);
1340                                 break;
1341                         case Opt_xprt_tcp6:
1342                                 protofamily = AF_INET6;
1343                         case Opt_xprt_tcp:
1344                                 mnt->flags |= NFS_MOUNT_TCP;
1345                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1346                                 kfree(string);
1347                                 break;
1348                         case Opt_xprt_rdma:
1349                                 /* vector side protocols to TCP */
1350                                 mnt->flags |= NFS_MOUNT_TCP;
1351                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1352                                 xprt_load_transport(string);
1353                                 kfree(string);
1354                                 break;
1355                         default:
1356                                 dfprintk(MOUNT, "NFS:   unrecognized "
1357                                                 "transport protocol\n");
1358                                 kfree(string);
1359                                 return 0;
1360                         }
1361                         break;
1362                 case Opt_mountproto:
1363                         string = match_strdup(args);
1364                         if (string == NULL)
1365                                 goto out_nomem;
1366                         token = match_token(string,
1367                                             nfs_xprt_protocol_tokens, args);
1368                         kfree(string);
1369
1370                         mountfamily = AF_INET;
1371                         switch (token) {
1372                         case Opt_xprt_udp6:
1373                                 mountfamily = AF_INET6;
1374                         case Opt_xprt_udp:
1375                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1376                                 break;
1377                         case Opt_xprt_tcp6:
1378                                 mountfamily = AF_INET6;
1379                         case Opt_xprt_tcp:
1380                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1381                                 break;
1382                         case Opt_xprt_rdma: /* not used for side protocols */
1383                         default:
1384                                 dfprintk(MOUNT, "NFS:   unrecognized "
1385                                                 "transport protocol\n");
1386                                 return 0;
1387                         }
1388                         break;
1389                 case Opt_addr:
1390                         string = match_strdup(args);
1391                         if (string == NULL)
1392                                 goto out_nomem;
1393                         mnt->nfs_server.addrlen =
1394                                 rpc_pton(string, strlen(string),
1395                                         (struct sockaddr *)
1396                                         &mnt->nfs_server.address,
1397                                         sizeof(mnt->nfs_server.address));
1398                         kfree(string);
1399                         if (mnt->nfs_server.addrlen == 0)
1400                                 goto out_invalid_address;
1401                         break;
1402                 case Opt_clientaddr:
1403                         string = match_strdup(args);
1404                         if (string == NULL)
1405                                 goto out_nomem;
1406                         kfree(mnt->client_address);
1407                         mnt->client_address = string;
1408                         break;
1409                 case Opt_mounthost:
1410                         string = match_strdup(args);
1411                         if (string == NULL)
1412                                 goto out_nomem;
1413                         kfree(mnt->mount_server.hostname);
1414                         mnt->mount_server.hostname = string;
1415                         break;
1416                 case Opt_mountaddr:
1417                         string = match_strdup(args);
1418                         if (string == NULL)
1419                                 goto out_nomem;
1420                         mnt->mount_server.addrlen =
1421                                 rpc_pton(string, strlen(string),
1422                                         (struct sockaddr *)
1423                                         &mnt->mount_server.address,
1424                                         sizeof(mnt->mount_server.address));
1425                         kfree(string);
1426                         if (mnt->mount_server.addrlen == 0)
1427                                 goto out_invalid_address;
1428                         break;
1429                 case Opt_lookupcache:
1430                         string = match_strdup(args);
1431                         if (string == NULL)
1432                                 goto out_nomem;
1433                         token = match_token(string,
1434                                         nfs_lookupcache_tokens, args);
1435                         kfree(string);
1436                         switch (token) {
1437                                 case Opt_lookupcache_all:
1438                                         mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1439                                         break;
1440                                 case Opt_lookupcache_positive:
1441                                         mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1442                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1443                                         break;
1444                                 case Opt_lookupcache_none:
1445                                         mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1446                                         break;
1447                                 default:
1448                                         dfprintk(MOUNT, "NFS:   invalid "
1449                                                         "lookupcache argument\n");
1450                                         return 0;
1451                         };
1452                         break;
1453                 case Opt_fscache_uniq:
1454                         string = match_strdup(args);
1455                         if (string == NULL)
1456                                 goto out_nomem;
1457                         kfree(mnt->fscache_uniq);
1458                         mnt->fscache_uniq = string;
1459                         mnt->options |= NFS_OPTION_FSCACHE;
1460                         break;
1461                 case Opt_local_lock:
1462                         string = match_strdup(args);
1463                         if (string == NULL)
1464                                 goto out_nomem;
1465                         token = match_token(string, nfs_local_lock_tokens,
1466                                         args);
1467                         kfree(string);
1468                         switch (token) {
1469                         case Opt_local_lock_all:
1470                                 mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1471                                                NFS_MOUNT_LOCAL_FCNTL);
1472                                 break;
1473                         case Opt_local_lock_flock:
1474                                 mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1475                                 break;
1476                         case Opt_local_lock_posix:
1477                                 mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1478                                 break;
1479                         case Opt_local_lock_none:
1480                                 mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1481                                                 NFS_MOUNT_LOCAL_FCNTL);
1482                                 break;
1483                         default:
1484                                 dfprintk(MOUNT, "NFS:   invalid "
1485                                                 "local_lock argument\n");
1486                                 return 0;
1487                         };
1488                         break;
1489
1490                 /*
1491                  * Special options
1492                  */
1493                 case Opt_sloppy:
1494                         sloppy = 1;
1495                         dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1496                         break;
1497                 case Opt_userspace:
1498                 case Opt_deprecated:
1499                         dfprintk(MOUNT, "NFS:   ignoring mount option "
1500                                         "'%s'\n", p);
1501                         break;
1502
1503                 default:
1504                         invalid_option = 1;
1505                         dfprintk(MOUNT, "NFS:   unrecognized mount option "
1506                                         "'%s'\n", p);
1507                 }
1508         }
1509
1510         if (!sloppy && invalid_option)
1511                 return 0;
1512
1513         /*
1514          * verify that any proto=/mountproto= options match the address
1515          * familiies in the addr=/mountaddr= options.
1516          */
1517         if (protofamily != AF_UNSPEC &&
1518             protofamily != mnt->nfs_server.address.ss_family)
1519                 goto out_proto_mismatch;
1520
1521         if (mountfamily != AF_UNSPEC) {
1522                 if (mnt->mount_server.addrlen) {
1523                         if (mountfamily != mnt->mount_server.address.ss_family)
1524                                 goto out_mountproto_mismatch;
1525                 } else {
1526                         if (mountfamily != mnt->nfs_server.address.ss_family)
1527                                 goto out_mountproto_mismatch;
1528                 }
1529         }
1530
1531         return 1;
1532
1533 out_mountproto_mismatch:
1534         printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1535                          "option\n");
1536         return 0;
1537 out_proto_mismatch:
1538         printk(KERN_INFO "NFS: server address does not match proto= option\n");
1539         return 0;
1540 out_invalid_address:
1541         printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1542         return 0;
1543 out_invalid_value:
1544         printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1545         return 0;
1546 out_nomem:
1547         printk(KERN_INFO "NFS: not enough memory to parse option\n");
1548         return 0;
1549 out_security_failure:
1550         free_secdata(secdata);
1551         printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1552         return 0;
1553 }
1554
1555 /*
1556  * Match the requested auth flavors with the list returned by
1557  * the server.  Returns zero and sets the mount's authentication
1558  * flavor on success; returns -EACCES if server does not support
1559  * the requested flavor.
1560  */
1561 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1562                              struct nfs_mount_request *request)
1563 {
1564         unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1565
1566         /*
1567          * Certain releases of Linux's mountd return an empty
1568          * flavor list.  To prevent behavioral regression with
1569          * these servers (ie. rejecting mounts that used to
1570          * succeed), revert to pre-2.6.32 behavior (no checking)
1571          * if the returned flavor list is empty.
1572          */
1573         if (server_authlist_len == 0)
1574                 return 0;
1575
1576         /*
1577          * We avoid sophisticated negotiating here, as there are
1578          * plenty of cases where we can get it wrong, providing
1579          * either too little or too much security.
1580          *
1581          * RFC 2623, section 2.7 suggests we SHOULD prefer the
1582          * flavor listed first.  However, some servers list
1583          * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1584          * preferred default, in args->auth_flavors[0] if user
1585          * didn't specify sec= mount option.
1586          */
1587         for (i = 0; i < args->auth_flavor_len; i++)
1588                 for (j = 0; j < server_authlist_len; j++)
1589                         if (args->auth_flavors[i] == request->auth_flavs[j]) {
1590                                 dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1591                                         request->auth_flavs[j]);
1592                                 args->auth_flavors[0] = request->auth_flavs[j];
1593                                 return 0;
1594                         }
1595
1596         dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1597         nfs_umount(request);
1598         return -EACCES;
1599 }
1600
1601 /*
1602  * Use the remote server's MOUNT service to request the NFS file handle
1603  * corresponding to the provided path.
1604  */
1605 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1606                          struct nfs_fh *root_fh)
1607 {
1608         rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1609         unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1610         struct nfs_mount_request request = {
1611                 .sap            = (struct sockaddr *)
1612                                                 &args->mount_server.address,
1613                 .dirpath        = args->nfs_server.export_path,
1614                 .protocol       = args->mount_server.protocol,
1615                 .fh             = root_fh,
1616                 .noresvport     = args->flags & NFS_MOUNT_NORESVPORT,
1617                 .auth_flav_len  = &server_authlist_len,
1618                 .auth_flavs     = server_authlist,
1619         };
1620         int status;
1621
1622         if (args->mount_server.version == 0) {
1623                 switch (args->version) {
1624                         default:
1625                                 args->mount_server.version = NFS_MNT3_VERSION;
1626                                 break;
1627                         case 2:
1628                                 args->mount_server.version = NFS_MNT_VERSION;
1629                 }
1630         }
1631         request.version = args->mount_server.version;
1632
1633         if (args->mount_server.hostname)
1634                 request.hostname = args->mount_server.hostname;
1635         else
1636                 request.hostname = args->nfs_server.hostname;
1637
1638         /*
1639          * Construct the mount server's address.
1640          */
1641         if (args->mount_server.address.ss_family == AF_UNSPEC) {
1642                 memcpy(request.sap, &args->nfs_server.address,
1643                        args->nfs_server.addrlen);
1644                 args->mount_server.addrlen = args->nfs_server.addrlen;
1645         }
1646         request.salen = args->mount_server.addrlen;
1647         nfs_set_port(request.sap, &args->mount_server.port, 0);
1648
1649         /*
1650          * Now ask the mount server to map our export path
1651          * to a file handle.
1652          */
1653         status = nfs_mount(&request);
1654         if (status != 0) {
1655                 dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1656                                 request.hostname, status);
1657                 return status;
1658         }
1659
1660         /*
1661          * MNTv1 (NFSv2) does not support auth flavor negotiation.
1662          */
1663         if (args->mount_server.version != NFS_MNT3_VERSION)
1664                 return 0;
1665         return nfs_walk_authlist(args, &request);
1666 }
1667
1668 static int nfs_parse_simple_hostname(const char *dev_name,
1669                                      char **hostname, size_t maxnamlen,
1670                                      char **export_path, size_t maxpathlen)
1671 {
1672         size_t len;
1673         char *colon, *comma;
1674
1675         colon = strchr(dev_name, ':');
1676         if (colon == NULL)
1677                 goto out_bad_devname;
1678
1679         len = colon - dev_name;
1680         if (len > maxnamlen)
1681                 goto out_hostname;
1682
1683         /* N.B. caller will free nfs_server.hostname in all cases */
1684         *hostname = kstrndup(dev_name, len, GFP_KERNEL);
1685         if (!*hostname)
1686                 goto out_nomem;
1687
1688         /* kill possible hostname list: not supported */
1689         comma = strchr(*hostname, ',');
1690         if (comma != NULL) {
1691                 if (comma == *hostname)
1692                         goto out_bad_devname;
1693                 *comma = '\0';
1694         }
1695
1696         colon++;
1697         len = strlen(colon);
1698         if (len > maxpathlen)
1699                 goto out_path;
1700         *export_path = kstrndup(colon, len, GFP_KERNEL);
1701         if (!*export_path)
1702                 goto out_nomem;
1703
1704         dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1705         return 0;
1706
1707 out_bad_devname:
1708         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1709         return -EINVAL;
1710
1711 out_nomem:
1712         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1713         return -ENOMEM;
1714
1715 out_hostname:
1716         dfprintk(MOUNT, "NFS: server hostname too long\n");
1717         return -ENAMETOOLONG;
1718
1719 out_path:
1720         dfprintk(MOUNT, "NFS: export pathname too long\n");
1721         return -ENAMETOOLONG;
1722 }
1723
1724 /*
1725  * Hostname has square brackets around it because it contains one or
1726  * more colons.  We look for the first closing square bracket, and a
1727  * colon must follow it.
1728  */
1729 static int nfs_parse_protected_hostname(const char *dev_name,
1730                                         char **hostname, size_t maxnamlen,
1731                                         char **export_path, size_t maxpathlen)
1732 {
1733         size_t len;
1734         char *start, *end;
1735
1736         start = (char *)(dev_name + 1);
1737
1738         end = strchr(start, ']');
1739         if (end == NULL)
1740                 goto out_bad_devname;
1741         if (*(end + 1) != ':')
1742                 goto out_bad_devname;
1743
1744         len = end - start;
1745         if (len > maxnamlen)
1746                 goto out_hostname;
1747
1748         /* N.B. caller will free nfs_server.hostname in all cases */
1749         *hostname = kstrndup(start, len, GFP_KERNEL);
1750         if (*hostname == NULL)
1751                 goto out_nomem;
1752
1753         end += 2;
1754         len = strlen(end);
1755         if (len > maxpathlen)
1756                 goto out_path;
1757         *export_path = kstrndup(end, len, GFP_KERNEL);
1758         if (!*export_path)
1759                 goto out_nomem;
1760
1761         return 0;
1762
1763 out_bad_devname:
1764         dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1765         return -EINVAL;
1766
1767 out_nomem:
1768         dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1769         return -ENOMEM;
1770
1771 out_hostname:
1772         dfprintk(MOUNT, "NFS: server hostname too long\n");
1773         return -ENAMETOOLONG;
1774
1775 out_path:
1776         dfprintk(MOUNT, "NFS: export pathname too long\n");
1777         return -ENAMETOOLONG;
1778 }
1779
1780 /*
1781  * Split "dev_name" into "hostname:export_path".
1782  *
1783  * The leftmost colon demarks the split between the server's hostname
1784  * and the export path.  If the hostname starts with a left square
1785  * bracket, then it may contain colons.
1786  *
1787  * Note: caller frees hostname and export path, even on error.
1788  */
1789 static int nfs_parse_devname(const char *dev_name,
1790                              char **hostname, size_t maxnamlen,
1791                              char **export_path, size_t maxpathlen)
1792 {
1793         if (*dev_name == '[')
1794                 return nfs_parse_protected_hostname(dev_name,
1795                                                     hostname, maxnamlen,
1796                                                     export_path, maxpathlen);
1797
1798         return nfs_parse_simple_hostname(dev_name,
1799                                          hostname, maxnamlen,
1800                                          export_path, maxpathlen);
1801 }
1802
1803 /*
1804  * Validate the NFS2/NFS3 mount data
1805  * - fills in the mount root filehandle
1806  *
1807  * For option strings, user space handles the following behaviors:
1808  *
1809  * + DNS: mapping server host name to IP address ("addr=" option)
1810  *
1811  * + failure mode: how to behave if a mount request can't be handled
1812  *   immediately ("fg/bg" option)
1813  *
1814  * + retry: how often to retry a mount request ("retry=" option)
1815  *
1816  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1817  *   mountproto=tcp after mountproto=udp, and so on
1818  */
1819 static int nfs_validate_mount_data(void *options,
1820                                    struct nfs_parsed_mount_data *args,
1821                                    struct nfs_fh *mntfh,
1822                                    const char *dev_name)
1823 {
1824         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1825         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1826
1827         if (data == NULL)
1828                 goto out_no_data;
1829
1830         switch (data->version) {
1831         case 1:
1832                 data->namlen = 0;
1833         case 2:
1834                 data->bsize = 0;
1835         case 3:
1836                 if (data->flags & NFS_MOUNT_VER3)
1837                         goto out_no_v3;
1838                 data->root.size = NFS2_FHSIZE;
1839                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1840         case 4:
1841                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1842                         goto out_no_sec;
1843         case 5:
1844                 memset(data->context, 0, sizeof(data->context));
1845         case 6:
1846                 if (data->flags & NFS_MOUNT_VER3) {
1847                         if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1848                                 goto out_invalid_fh;
1849                         mntfh->size = data->root.size;
1850                         args->version = 3;
1851                 } else {
1852                         mntfh->size = NFS2_FHSIZE;
1853                         args->version = 2;
1854                 }
1855
1856
1857                 memcpy(mntfh->data, data->root.data, mntfh->size);
1858                 if (mntfh->size < sizeof(mntfh->data))
1859                         memset(mntfh->data + mntfh->size, 0,
1860                                sizeof(mntfh->data) - mntfh->size);
1861
1862                 /*
1863                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1864                  * can deal with.
1865                  */
1866                 args->flags             = data->flags & NFS_MOUNT_FLAGMASK;
1867                 args->flags             |= NFS_MOUNT_LEGACY_INTERFACE;
1868                 args->rsize             = data->rsize;
1869                 args->wsize             = data->wsize;
1870                 args->timeo             = data->timeo;
1871                 args->retrans           = data->retrans;
1872                 args->acregmin          = data->acregmin;
1873                 args->acregmax          = data->acregmax;
1874                 args->acdirmin          = data->acdirmin;
1875                 args->acdirmax          = data->acdirmax;
1876
1877                 memcpy(sap, &data->addr, sizeof(data->addr));
1878                 args->nfs_server.addrlen = sizeof(data->addr);
1879                 if (!nfs_verify_server_address(sap))
1880                         goto out_no_address;
1881
1882                 if (!(data->flags & NFS_MOUNT_TCP))
1883                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1884                 /* N.B. caller will free nfs_server.hostname in all cases */
1885                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1886                 args->namlen            = data->namlen;
1887                 args->bsize             = data->bsize;
1888
1889                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1890                         args->auth_flavors[0] = data->pseudoflavor;
1891                 if (!args->nfs_server.hostname)
1892                         goto out_nomem;
1893
1894                 if (!(data->flags & NFS_MOUNT_NONLM))
1895                         args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1896                                          NFS_MOUNT_LOCAL_FCNTL);
1897                 else
1898                         args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1899                                         NFS_MOUNT_LOCAL_FCNTL);
1900                 /*
1901                  * The legacy version 6 binary mount data from userspace has a
1902                  * field used only to transport selinux information into the
1903                  * the kernel.  To continue to support that functionality we
1904                  * have a touch of selinux knowledge here in the NFS code. The
1905                  * userspace code converted context=blah to just blah so we are
1906                  * converting back to the full string selinux understands.
1907                  */
1908                 if (data->context[0]){
1909 #ifdef CONFIG_SECURITY_SELINUX
1910                         int rc;
1911                         char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1912                         if (!opts_str)
1913                                 return -ENOMEM;
1914                         strcpy(opts_str, "context=");
1915                         data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1916                         strcat(opts_str, &data->context[0]);
1917                         rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1918                         kfree(opts_str);
1919                         if (rc)
1920                                 return rc;
1921 #else
1922                         return -EINVAL;
1923 #endif
1924                 }
1925
1926                 break;
1927         default: {
1928                 int status;
1929
1930                 if (nfs_parse_mount_options((char *)options, args) == 0)
1931                         return -EINVAL;
1932
1933                 if (!nfs_verify_server_address(sap))
1934                         goto out_no_address;
1935
1936                 if (args->version == 4)
1937 #ifdef CONFIG_NFS_V4
1938                         return nfs4_validate_text_mount_data(options,
1939                                                              args, dev_name);
1940 #else
1941                         goto out_v4_not_compiled;
1942 #endif
1943
1944                 nfs_set_port(sap, &args->nfs_server.port, 0);
1945
1946                 nfs_set_mount_transport_protocol(args);
1947
1948                 status = nfs_parse_devname(dev_name,
1949                                            &args->nfs_server.hostname,
1950                                            PAGE_SIZE,
1951                                            &args->nfs_server.export_path,
1952                                            NFS_MAXPATHLEN);
1953                 if (!status)
1954                         status = nfs_try_mount(args, mntfh);
1955
1956                 kfree(args->nfs_server.export_path);
1957                 args->nfs_server.export_path = NULL;
1958
1959                 if (status)
1960                         return status;
1961
1962                 break;
1963                 }
1964         }
1965
1966 #ifndef CONFIG_NFS_V3
1967         if (args->version == 3)
1968                 goto out_v3_not_compiled;
1969 #endif /* !CONFIG_NFS_V3 */
1970
1971         return 0;
1972
1973 out_no_data:
1974         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1975         return -EINVAL;
1976
1977 out_no_v3:
1978         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1979                  data->version);
1980         return -EINVAL;
1981
1982 out_no_sec:
1983         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1984         return -EINVAL;
1985
1986 #ifndef CONFIG_NFS_V3
1987 out_v3_not_compiled:
1988         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1989         return -EPROTONOSUPPORT;
1990 #endif /* !CONFIG_NFS_V3 */
1991
1992 #ifndef CONFIG_NFS_V4
1993 out_v4_not_compiled:
1994         dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1995         return -EPROTONOSUPPORT;
1996 #endif /* !CONFIG_NFS_V4 */
1997
1998 out_nomem:
1999         dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
2000         return -ENOMEM;
2001
2002 out_no_address:
2003         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2004         return -EINVAL;
2005
2006 out_invalid_fh:
2007         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2008         return -EINVAL;
2009 }
2010
2011 static int
2012 nfs_compare_remount_data(struct nfs_server *nfss,
2013                          struct nfs_parsed_mount_data *data)
2014 {
2015         if (data->flags != nfss->flags ||
2016             data->rsize != nfss->rsize ||
2017             data->wsize != nfss->wsize ||
2018             data->retrans != nfss->client->cl_timeout->to_retries ||
2019             data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2020             data->acregmin != nfss->acregmin / HZ ||
2021             data->acregmax != nfss->acregmax / HZ ||
2022             data->acdirmin != nfss->acdirmin / HZ ||
2023             data->acdirmax != nfss->acdirmax / HZ ||
2024             data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2025             data->nfs_server.port != nfss->port ||
2026             data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2027             !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2028                           (struct sockaddr *)&nfss->nfs_client->cl_addr))
2029                 return -EINVAL;
2030
2031         return 0;
2032 }
2033
2034 static int
2035 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2036 {
2037         int error;
2038         struct nfs_server *nfss = sb->s_fs_info;
2039         struct nfs_parsed_mount_data *data;
2040         struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2041         struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2042         u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2043
2044         /*
2045          * Userspace mount programs that send binary options generally send
2046          * them populated with default values. We have no way to know which
2047          * ones were explicitly specified. Fall back to legacy behavior and
2048          * just return success.
2049          */
2050         if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2051             (nfsvers <= 3 && (!options || (options->version >= 1 &&
2052                                            options->version <= 6))))
2053                 return 0;
2054
2055         data = kzalloc(sizeof(*data), GFP_KERNEL);
2056         if (data == NULL)
2057                 return -ENOMEM;
2058
2059         /* fill out struct with values from existing mount */
2060         data->flags = nfss->flags;
2061         data->rsize = nfss->rsize;
2062         data->wsize = nfss->wsize;
2063         data->retrans = nfss->client->cl_timeout->to_retries;
2064         data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2065         data->acregmin = nfss->acregmin / HZ;
2066         data->acregmax = nfss->acregmax / HZ;
2067         data->acdirmin = nfss->acdirmin / HZ;
2068         data->acdirmax = nfss->acdirmax / HZ;
2069         data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2070         data->nfs_server.port = nfss->port;
2071         data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2072         memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2073                 data->nfs_server.addrlen);
2074
2075         /* overwrite those values with any that were specified */
2076         error = nfs_parse_mount_options((char *)options, data);
2077         if (error < 0)
2078                 goto out;
2079
2080         /* compare new mount options with old ones */
2081         error = nfs_compare_remount_data(nfss, data);
2082 out:
2083         kfree(data);
2084         return error;
2085 }
2086
2087 /*
2088  * Initialise the common bits of the superblock
2089  */
2090 static inline void nfs_initialise_sb(struct super_block *sb)
2091 {
2092         struct nfs_server *server = NFS_SB(sb);
2093
2094         sb->s_magic = NFS_SUPER_MAGIC;
2095
2096         /* We probably want something more informative here */
2097         snprintf(sb->s_id, sizeof(sb->s_id),
2098                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2099
2100         if (sb->s_blocksize == 0)
2101                 sb->s_blocksize = nfs_block_bits(server->wsize,
2102                                                  &sb->s_blocksize_bits);
2103
2104         if (server->flags & NFS_MOUNT_NOAC)
2105                 sb->s_flags |= MS_SYNCHRONOUS;
2106
2107         sb->s_bdi = &server->backing_dev_info;
2108
2109         nfs_super_set_maxbytes(sb, server->maxfilesize);
2110 }
2111
2112 /*
2113  * Finish setting up an NFS2/3 superblock
2114  */
2115 static void nfs_fill_super(struct super_block *sb,
2116                            struct nfs_parsed_mount_data *data)
2117 {
2118         struct nfs_server *server = NFS_SB(sb);
2119
2120         sb->s_blocksize_bits = 0;
2121         sb->s_blocksize = 0;
2122         if (data->bsize)
2123                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2124
2125         if (server->nfs_client->rpc_ops->version == 3) {
2126                 /* The VFS shouldn't apply the umask to mode bits. We will do
2127                  * so ourselves when necessary.
2128                  */
2129                 sb->s_flags |= MS_POSIXACL;
2130                 sb->s_time_gran = 1;
2131         }
2132
2133         sb->s_op = &nfs_sops;
2134         nfs_initialise_sb(sb);
2135 }
2136
2137 /*
2138  * Finish setting up a cloned NFS2/3 superblock
2139  */
2140 static void nfs_clone_super(struct super_block *sb,
2141                             const struct super_block *old_sb)
2142 {
2143         struct nfs_server *server = NFS_SB(sb);
2144
2145         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2146         sb->s_blocksize = old_sb->s_blocksize;
2147         sb->s_maxbytes = old_sb->s_maxbytes;
2148
2149         if (server->nfs_client->rpc_ops->version == 3) {
2150                 /* The VFS shouldn't apply the umask to mode bits. We will do
2151                  * so ourselves when necessary.
2152                  */
2153                 sb->s_flags |= MS_POSIXACL;
2154                 sb->s_time_gran = 1;
2155         }
2156
2157         sb->s_op = old_sb->s_op;
2158         nfs_initialise_sb(sb);
2159 }
2160
2161 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2162 {
2163         const struct nfs_server *a = s->s_fs_info;
2164         const struct rpc_clnt *clnt_a = a->client;
2165         const struct rpc_clnt *clnt_b = b->client;
2166
2167         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2168                 goto Ebusy;
2169         if (a->nfs_client != b->nfs_client)
2170                 goto Ebusy;
2171         if (a->flags != b->flags)
2172                 goto Ebusy;
2173         if (a->wsize != b->wsize)
2174                 goto Ebusy;
2175         if (a->rsize != b->rsize)
2176                 goto Ebusy;
2177         if (a->acregmin != b->acregmin)
2178                 goto Ebusy;
2179         if (a->acregmax != b->acregmax)
2180                 goto Ebusy;
2181         if (a->acdirmin != b->acdirmin)
2182                 goto Ebusy;
2183         if (a->acdirmax != b->acdirmax)
2184                 goto Ebusy;
2185         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2186                 goto Ebusy;
2187         return 1;
2188 Ebusy:
2189         return 0;
2190 }
2191
2192 struct nfs_sb_mountdata {
2193         struct nfs_server *server;
2194         int mntflags;
2195 };
2196
2197 static int nfs_set_super(struct super_block *s, void *data)
2198 {
2199         struct nfs_sb_mountdata *sb_mntdata = data;
2200         struct nfs_server *server = sb_mntdata->server;
2201         int ret;
2202
2203         s->s_flags = sb_mntdata->mntflags;
2204         s->s_fs_info = server;
2205         s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
2206         ret = set_anon_super(s, server);
2207         if (ret == 0)
2208                 server->s_dev = s->s_dev;
2209         return ret;
2210 }
2211
2212 static int nfs_compare_super_address(struct nfs_server *server1,
2213                                      struct nfs_server *server2)
2214 {
2215         struct sockaddr *sap1, *sap2;
2216
2217         sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2218         sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2219
2220         if (sap1->sa_family != sap2->sa_family)
2221                 return 0;
2222
2223         switch (sap1->sa_family) {
2224         case AF_INET: {
2225                 struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2226                 struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2227                 if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2228                         return 0;
2229                 if (sin1->sin_port != sin2->sin_port)
2230                         return 0;
2231                 break;
2232         }
2233         case AF_INET6: {
2234                 struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2235                 struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2236                 if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2237                         return 0;
2238                 if (sin1->sin6_port != sin2->sin6_port)
2239                         return 0;
2240                 break;
2241         }
2242         default:
2243                 return 0;
2244         }
2245
2246         return 1;
2247 }
2248
2249 static int nfs_compare_super(struct super_block *sb, void *data)
2250 {
2251         struct nfs_sb_mountdata *sb_mntdata = data;
2252         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2253         int mntflags = sb_mntdata->mntflags;
2254
2255         if (!nfs_compare_super_address(old, server))
2256                 return 0;
2257         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2258         if (old->flags & NFS_MOUNT_UNSHARED)
2259                 return 0;
2260         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2261                 return 0;
2262         return nfs_compare_mount_options(sb, server, mntflags);
2263 }
2264
2265 static int nfs_bdi_register(struct nfs_server *server)
2266 {
2267         return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2268 }
2269
2270 static int nfs_get_sb(struct file_system_type *fs_type,
2271         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2272 {
2273         struct nfs_server *server = NULL;
2274         struct super_block *s;
2275         struct nfs_parsed_mount_data *data;
2276         struct nfs_fh *mntfh;
2277         struct dentry *mntroot;
2278         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2279         struct nfs_sb_mountdata sb_mntdata = {
2280                 .mntflags = flags,
2281         };
2282         int error = -ENOMEM;
2283
2284         data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
2285         mntfh = nfs_alloc_fhandle();
2286         if (data == NULL || mntfh == NULL)
2287                 goto out_free_fh;
2288
2289         security_init_mnt_opts(&data->lsm_opts);
2290
2291         /* Validate the mount data */
2292         error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2293         if (error < 0)
2294                 goto out;
2295
2296 #ifdef CONFIG_NFS_V4
2297         if (data->version == 4) {
2298                 error = nfs4_try_mount(flags, dev_name, data, mnt);
2299                 kfree(data->client_address);
2300                 kfree(data->nfs_server.export_path);
2301                 goto out;
2302         }
2303 #endif  /* CONFIG_NFS_V4 */
2304
2305         /* Get a volume representation */
2306         server = nfs_create_server(data, mntfh);
2307         if (IS_ERR(server)) {
2308                 error = PTR_ERR(server);
2309                 goto out;
2310         }
2311         sb_mntdata.server = server;
2312
2313         if (server->flags & NFS_MOUNT_UNSHARED)
2314                 compare_super = NULL;
2315
2316         /* Get a superblock - note that we may end up sharing one that already exists */
2317         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2318         if (IS_ERR(s)) {
2319                 error = PTR_ERR(s);
2320                 goto out_err_nosb;
2321         }
2322
2323         if (s->s_fs_info != server) {
2324                 nfs_free_server(server);
2325                 server = NULL;
2326         } else {
2327                 error = nfs_bdi_register(server);
2328                 if (error)
2329                         goto error_splat_bdi;
2330         }
2331
2332         if (!s->s_root) {
2333                 /* initial superblock/root creation */
2334                 nfs_fill_super(s, data);
2335                 nfs_fscache_get_super_cookie(
2336                         s, data ? data->fscache_uniq : NULL, NULL);
2337         }
2338
2339         mntroot = nfs_get_root(s, mntfh);
2340         if (IS_ERR(mntroot)) {
2341                 error = PTR_ERR(mntroot);
2342                 goto error_splat_super;
2343         }
2344
2345         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2346         if (error)
2347                 goto error_splat_root;
2348
2349         s->s_flags |= MS_ACTIVE;
2350         mnt->mnt_sb = s;
2351         mnt->mnt_root = mntroot;
2352         error = 0;
2353
2354 out:
2355         kfree(data->nfs_server.hostname);
2356         kfree(data->mount_server.hostname);
2357         kfree(data->fscache_uniq);
2358         security_free_mnt_opts(&data->lsm_opts);
2359 out_free_fh:
2360         nfs_free_fhandle(mntfh);
2361         kfree(data);
2362         return error;
2363
2364 out_err_nosb:
2365         nfs_free_server(server);
2366         goto out;
2367
2368 error_splat_root:
2369         dput(mntroot);
2370 error_splat_super:
2371         if (server && !s->s_root)
2372                 bdi_unregister(&server->backing_dev_info);
2373 error_splat_bdi:
2374         deactivate_locked_super(s);
2375         goto out;
2376 }
2377
2378 /*
2379  * Ensure that we unregister the bdi before kill_anon_super
2380  * releases the device name
2381  */
2382 static void nfs_put_super(struct super_block *s)
2383 {
2384         struct nfs_server *server = NFS_SB(s);
2385
2386         bdi_unregister(&server->backing_dev_info);
2387 }
2388
2389 /*
2390  * Destroy an NFS2/3 superblock
2391  */
2392 static void nfs_kill_super(struct super_block *s)
2393 {
2394         struct nfs_server *server = NFS_SB(s);
2395
2396         kill_anon_super(s);
2397         nfs_fscache_release_super_cookie(s);
2398         nfs_free_server(server);
2399 }
2400
2401 /*
2402  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2403  */
2404 static struct dentry *
2405 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2406                 const char *dev_name, void *raw_data)
2407 {
2408         struct nfs_clone_mount *data = raw_data;
2409         struct super_block *s;
2410         struct nfs_server *server;
2411         struct dentry *mntroot;
2412         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2413         struct nfs_sb_mountdata sb_mntdata = {
2414                 .mntflags = flags,
2415         };
2416         int error;
2417
2418         dprintk("--> nfs_xdev_mount()\n");
2419
2420         /* create a new volume representation */
2421         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2422         if (IS_ERR(server)) {
2423                 error = PTR_ERR(server);
2424                 goto out_err_noserver;
2425         }
2426         sb_mntdata.server = server;
2427
2428         if (server->flags & NFS_MOUNT_UNSHARED)
2429                 compare_super = NULL;
2430
2431         /* Get a superblock - note that we may end up sharing one that already exists */
2432         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2433         if (IS_ERR(s)) {
2434                 error = PTR_ERR(s);
2435                 goto out_err_nosb;
2436         }
2437
2438         if (s->s_fs_info != server) {
2439                 nfs_free_server(server);
2440                 server = NULL;
2441         } else {
2442                 error = nfs_bdi_register(server);
2443                 if (error)
2444                         goto error_splat_bdi;
2445         }
2446
2447         if (!s->s_root) {
2448                 /* initial superblock/root creation */
2449                 nfs_clone_super(s, data->sb);
2450                 nfs_fscache_get_super_cookie(s, NULL, data);
2451         }
2452
2453         mntroot = nfs_get_root(s, data->fh);
2454         if (IS_ERR(mntroot)) {
2455                 error = PTR_ERR(mntroot);
2456                 goto error_splat_super;
2457         }
2458         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2459                 dput(mntroot);
2460                 error = -ESTALE;
2461                 goto error_splat_super;
2462         }
2463
2464         s->s_flags |= MS_ACTIVE;
2465
2466         /* clone any lsm security options from the parent to the new sb */
2467         security_sb_clone_mnt_opts(data->sb, s);
2468
2469         dprintk("<-- nfs_xdev_mount() = 0\n");
2470         return mntroot;
2471
2472 out_err_nosb:
2473         nfs_free_server(server);
2474 out_err_noserver:
2475         dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2476         return ERR_PTR(error);
2477
2478 error_splat_super:
2479         if (server && !s->s_root)
2480                 bdi_unregister(&server->backing_dev_info);
2481 error_splat_bdi:
2482         deactivate_locked_super(s);
2483         dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2484         return ERR_PTR(error);
2485 }
2486
2487 #ifdef CONFIG_NFS_V4
2488
2489 /*
2490  * Finish setting up a cloned NFS4 superblock
2491  */
2492 static void nfs4_clone_super(struct super_block *sb,
2493                             const struct super_block *old_sb)
2494 {
2495         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2496         sb->s_blocksize = old_sb->s_blocksize;
2497         sb->s_maxbytes = old_sb->s_maxbytes;
2498         sb->s_time_gran = 1;
2499         sb->s_op = old_sb->s_op;
2500         /*
2501          * The VFS shouldn't apply the umask to mode bits. We will do
2502          * so ourselves when necessary.
2503          */
2504         sb->s_flags  |= MS_POSIXACL;
2505         sb->s_xattr  = old_sb->s_xattr;
2506         nfs_initialise_sb(sb);
2507 }
2508
2509 /*
2510  * Set up an NFS4 superblock
2511  */
2512 static void nfs4_fill_super(struct super_block *sb)
2513 {
2514         sb->s_time_gran = 1;
2515         sb->s_op = &nfs4_sops;
2516         /*
2517          * The VFS shouldn't apply the umask to mode bits. We will do
2518          * so ourselves when necessary.
2519          */
2520         sb->s_flags  |= MS_POSIXACL;
2521         sb->s_xattr = nfs4_xattr_handlers;
2522         nfs_initialise_sb(sb);
2523 }
2524
2525 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2526 {
2527         args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2528                          NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2529 }
2530
2531 static int nfs4_validate_text_mount_data(void *options,
2532                                          struct nfs_parsed_mount_data *args,
2533                                          const char *dev_name)
2534 {
2535         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2536
2537         nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2538
2539         nfs_validate_transport_protocol(args);
2540
2541         nfs4_validate_mount_flags(args);
2542
2543         if (args->version != 4) {
2544                 dfprintk(MOUNT,
2545                          "NFS4: Illegal mount version\n");
2546                 return -EINVAL;
2547         }
2548
2549         if (args->auth_flavor_len > 1) {
2550                 dfprintk(MOUNT,
2551                          "NFS4: Too many RPC auth flavours specified\n");
2552                 return -EINVAL;
2553         }
2554
2555         if (args->client_address == NULL) {
2556                 dfprintk(MOUNT,
2557                          "NFS4: mount program didn't pass callback address\n");
2558                 return -EINVAL;
2559         }
2560
2561         return nfs_parse_devname(dev_name,
2562                                    &args->nfs_server.hostname,
2563                                    NFS4_MAXNAMLEN,
2564                                    &args->nfs_server.export_path,
2565                                    NFS4_MAXPATHLEN);
2566 }
2567
2568 /*
2569  * Validate NFSv4 mount options
2570  */
2571 static int nfs4_validate_mount_data(void *options,
2572                                     struct nfs_parsed_mount_data *args,
2573                                     const char *dev_name)
2574 {
2575         struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2576         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2577         char *c;
2578
2579         if (data == NULL)
2580                 goto out_no_data;
2581
2582         switch (data->version) {
2583         case 1:
2584                 if (data->host_addrlen > sizeof(args->nfs_server.address))
2585                         goto out_no_address;
2586                 if (data->host_addrlen == 0)
2587                         goto out_no_address;
2588                 args->nfs_server.addrlen = data->host_addrlen;
2589                 if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2590                         return -EFAULT;
2591                 if (!nfs_verify_server_address(sap))
2592                         goto out_no_address;
2593
2594                 if (data->auth_flavourlen) {
2595                         if (data->auth_flavourlen > 1)
2596                                 goto out_inval_auth;
2597                         if (copy_from_user(&args->auth_flavors[0],
2598                                            data->auth_flavours,
2599                                            sizeof(args->auth_flavors[0])))
2600                                 return -EFAULT;
2601                 }
2602
2603                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2604                 if (IS_ERR(c))
2605                         return PTR_ERR(c);
2606                 args->nfs_server.hostname = c;
2607
2608                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2609                 if (IS_ERR(c))
2610                         return PTR_ERR(c);
2611                 args->nfs_server.export_path = c;
2612                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2613
2614                 c = strndup_user(data->client_addr.data, 16);
2615                 if (IS_ERR(c))
2616                         return PTR_ERR(c);
2617                 args->client_address = c;
2618
2619                 /*
2620                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2621                  * can deal with.
2622                  */
2623
2624                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
2625                 args->rsize     = data->rsize;
2626                 args->wsize     = data->wsize;
2627                 args->timeo     = data->timeo;
2628                 args->retrans   = data->retrans;
2629                 args->acregmin  = data->acregmin;
2630                 args->acregmax  = data->acregmax;
2631                 args->acdirmin  = data->acdirmin;
2632                 args->acdirmax  = data->acdirmax;
2633                 args->nfs_server.protocol = data->proto;
2634                 nfs_validate_transport_protocol(args);
2635
2636                 break;
2637         default:
2638                 if (nfs_parse_mount_options((char *)options, args) == 0)
2639                         return -EINVAL;
2640
2641                 if (!nfs_verify_server_address(sap))
2642                         return -EINVAL;
2643
2644                 return nfs4_validate_text_mount_data(options, args, dev_name);
2645         }
2646
2647         return 0;
2648
2649 out_no_data:
2650         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2651         return -EINVAL;
2652
2653 out_inval_auth:
2654         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2655                  data->auth_flavourlen);
2656         return -EINVAL;
2657
2658 out_no_address:
2659         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2660         return -EINVAL;
2661 }
2662
2663 /*
2664  * Get the superblock for the NFS4 root partition
2665  */
2666 static struct dentry *
2667 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2668                   const char *dev_name, void *raw_data)
2669 {
2670         struct nfs_parsed_mount_data *data = raw_data;
2671         struct super_block *s;
2672         struct nfs_server *server;
2673         struct nfs_fh *mntfh;
2674         struct dentry *mntroot;
2675         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2676         struct nfs_sb_mountdata sb_mntdata = {
2677                 .mntflags = flags,
2678         };
2679         int error = -ENOMEM;
2680
2681         mntfh = nfs_alloc_fhandle();
2682         if (data == NULL || mntfh == NULL)
2683                 goto out_free_fh;
2684
2685         security_init_mnt_opts(&data->lsm_opts);
2686
2687         /* Get a volume representation */
2688         server = nfs4_create_server(data, mntfh);
2689         if (IS_ERR(server)) {
2690                 error = PTR_ERR(server);
2691                 goto out;
2692         }
2693         sb_mntdata.server = server;
2694
2695         if (server->flags & NFS4_MOUNT_UNSHARED)
2696                 compare_super = NULL;
2697
2698         /* Get a superblock - note that we may end up sharing one that already exists */
2699         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2700         if (IS_ERR(s)) {
2701                 error = PTR_ERR(s);
2702                 goto out_free;
2703         }
2704
2705         if (s->s_fs_info != server) {
2706                 nfs_free_server(server);
2707                 server = NULL;
2708         } else {
2709                 error = nfs_bdi_register(server);
2710                 if (error)
2711                         goto error_splat_bdi;
2712         }
2713
2714         if (!s->s_root) {
2715                 /* initial superblock/root creation */
2716                 nfs4_fill_super(s);
2717                 nfs_fscache_get_super_cookie(
2718                         s, data ? data->fscache_uniq : NULL, NULL);
2719         }
2720
2721         mntroot = nfs4_get_root(s, mntfh);
2722         if (IS_ERR(mntroot)) {
2723                 error = PTR_ERR(mntroot);
2724                 goto error_splat_super;
2725         }
2726
2727         error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2728         if (error)
2729                 goto error_splat_root;
2730
2731         s->s_flags |= MS_ACTIVE;
2732
2733         security_free_mnt_opts(&data->lsm_opts);
2734         nfs_free_fhandle(mntfh);
2735         return mntroot;
2736
2737 out:
2738         security_free_mnt_opts(&data->lsm_opts);
2739 out_free_fh:
2740         nfs_free_fhandle(mntfh);
2741         return ERR_PTR(error);
2742
2743 out_free:
2744         nfs_free_server(server);
2745         goto out;
2746
2747 error_splat_root:
2748         dput(mntroot);
2749 error_splat_super:
2750         if (server && !s->s_root)
2751                 bdi_unregister(&server->backing_dev_info);
2752 error_splat_bdi:
2753         deactivate_locked_super(s);
2754         goto out;
2755 }
2756
2757 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2758                 int flags, void *data, const char *hostname)
2759 {
2760         struct vfsmount *root_mnt;
2761         char *root_devname;
2762         size_t len;
2763
2764         len = strlen(hostname) + 3;
2765         root_devname = kmalloc(len, GFP_KERNEL);
2766         if (root_devname == NULL)
2767                 return ERR_PTR(-ENOMEM);
2768         snprintf(root_devname, len, "%s:/", hostname);
2769         root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2770         kfree(root_devname);
2771         return root_mnt;
2772 }
2773
2774 static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
2775 {
2776         char *page = (char *) __get_free_page(GFP_KERNEL);
2777         char *devname, *tmp;
2778
2779         if (page == NULL)
2780                 return;
2781         devname = nfs_path(path->mnt->mnt_devname,
2782                         path->mnt->mnt_root, path->dentry,
2783                         page, PAGE_SIZE);
2784         if (IS_ERR(devname))
2785                 goto out_freepage;
2786         tmp = kstrdup(devname, GFP_KERNEL);
2787         if (tmp == NULL)
2788                 goto out_freepage;
2789         kfree(mnt->mnt_devname);
2790         mnt->mnt_devname = tmp;
2791 out_freepage:
2792         free_page((unsigned long)page);
2793 }
2794
2795 struct nfs_referral_count {
2796         struct list_head list;
2797         const struct task_struct *task;
2798         unsigned int referral_count;
2799 };
2800
2801 static LIST_HEAD(nfs_referral_count_list);
2802 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2803
2804 static struct nfs_referral_count *nfs_find_referral_count(void)
2805 {
2806         struct nfs_referral_count *p;
2807
2808         list_for_each_entry(p, &nfs_referral_count_list, list) {
2809                 if (p->task == current)
2810                         return p;
2811         }
2812         return NULL;
2813 }
2814
2815 #define NFS_MAX_NESTED_REFERRALS 2
2816
2817 static int nfs_referral_loop_protect(void)
2818 {
2819         struct nfs_referral_count *p, *new;
2820         int ret = -ENOMEM;
2821
2822         new = kmalloc(sizeof(*new), GFP_KERNEL);
2823         if (!new)
2824                 goto out;
2825         new->task = current;
2826         new->referral_count = 1;
2827
2828         ret = 0;
2829         spin_lock(&nfs_referral_count_list_lock);
2830         p = nfs_find_referral_count();
2831         if (p != NULL) {
2832                 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2833                         ret = -ELOOP;
2834                 else
2835                         p->referral_count++;
2836         } else {
2837                 list_add(&new->list, &nfs_referral_count_list);
2838                 new = NULL;
2839         }
2840         spin_unlock(&nfs_referral_count_list_lock);
2841         kfree(new);
2842 out:
2843         return ret;
2844 }
2845
2846 static void nfs_referral_loop_unprotect(void)
2847 {
2848         struct nfs_referral_count *p;
2849
2850         spin_lock(&nfs_referral_count_list_lock);
2851         p = nfs_find_referral_count();
2852         p->referral_count--;
2853         if (p->referral_count == 0)
2854                 list_del(&p->list);
2855         else
2856                 p = NULL;
2857         spin_unlock(&nfs_referral_count_list_lock);
2858         kfree(p);
2859 }
2860
2861 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
2862                 const char *export_path, struct vfsmount *mnt_target)
2863 {
2864         struct nameidata *nd = NULL;
2865         struct mnt_namespace *ns_private;
2866         struct super_block *s;
2867         int ret;
2868
2869         nd = kmalloc(sizeof(*nd), GFP_KERNEL);
2870         if (nd == NULL)
2871                 return -ENOMEM;
2872
2873         ns_private = create_mnt_ns(root_mnt);
2874         ret = PTR_ERR(ns_private);
2875         if (IS_ERR(ns_private))
2876                 goto out_mntput;
2877
2878         ret = nfs_referral_loop_protect();
2879         if (ret != 0)
2880                 goto out_put_mnt_ns;
2881
2882         ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
2883                         export_path, LOOKUP_FOLLOW, nd);
2884
2885         nfs_referral_loop_unprotect();
2886         put_mnt_ns(ns_private);
2887
2888         if (ret != 0)
2889                 goto out_err;
2890
2891         s = nd->path.mnt->mnt_sb;
2892         atomic_inc(&s->s_active);
2893         mnt_target->mnt_sb = s;
2894         mnt_target->mnt_root = dget(nd->path.dentry);
2895
2896         /* Correct the device pathname */
2897         nfs_fix_devname(&nd->path, mnt_target);
2898
2899         path_put(&nd->path);
2900         kfree(nd);
2901         down_write(&s->s_umount);
2902         return 0;
2903 out_put_mnt_ns:
2904         put_mnt_ns(ns_private);
2905 out_mntput:
2906         mntput(root_mnt);
2907 out_err:
2908         kfree(nd);
2909         return ret;
2910 }
2911
2912 static int nfs4_try_mount(int flags, const char *dev_name,
2913                          struct nfs_parsed_mount_data *data,
2914                          struct vfsmount *mnt)
2915 {
2916         char *export_path;
2917         struct vfsmount *root_mnt;
2918         int error;
2919
2920         dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2921
2922         export_path = data->nfs_server.export_path;
2923         data->nfs_server.export_path = "/";
2924         root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2925                         data->nfs_server.hostname);
2926         data->nfs_server.export_path = export_path;
2927
2928         error = PTR_ERR(root_mnt);
2929         if (IS_ERR(root_mnt))
2930                 goto out;
2931
2932         error = nfs_follow_remote_path(root_mnt, export_path, mnt);
2933
2934 out:
2935         dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
2936                         error != 0 ? " [error]" : "");
2937         return error;
2938 }
2939
2940 /*
2941  * Get the superblock for an NFS4 mountpoint
2942  */
2943 static int nfs4_get_sb(struct file_system_type *fs_type,
2944         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2945 {
2946         struct nfs_parsed_mount_data *data;
2947         int error = -ENOMEM;
2948
2949         data = nfs_alloc_parsed_mount_data(4);
2950         if (data == NULL)
2951                 goto out_free_data;
2952
2953         /* Validate the mount data */
2954         error = nfs4_validate_mount_data(raw_data, data, dev_name);
2955         if (error < 0)
2956                 goto out;
2957
2958         error = nfs4_try_mount(flags, dev_name, data, mnt);
2959
2960 out:
2961         kfree(data->client_address);
2962         kfree(data->nfs_server.export_path);
2963         kfree(data->nfs_server.hostname);
2964         kfree(data->fscache_uniq);
2965 out_free_data:
2966         kfree(data);
2967         dprintk("<-- nfs4_get_sb() = %d%s\n", error,
2968                         error != 0 ? " [error]" : "");
2969         return error;
2970 }
2971
2972 static void nfs4_kill_super(struct super_block *sb)
2973 {
2974         struct nfs_server *server = NFS_SB(sb);
2975
2976         dprintk("--> %s\n", __func__);
2977         nfs_super_return_all_delegations(sb);
2978         kill_anon_super(sb);
2979         nfs_fscache_release_super_cookie(sb);
2980         nfs_free_server(server);
2981         dprintk("<-- %s\n", __func__);
2982 }
2983
2984 /*
2985  * Clone an NFS4 server record on xdev traversal (FSID-change)
2986  */
2987 static struct dentry *
2988 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2989                  const char *dev_name, void *raw_data)
2990 {
2991         struct nfs_clone_mount *data = raw_data;
2992         struct super_block *s;
2993         struct nfs_server *server;
2994         struct dentry *mntroot;
2995         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2996         struct nfs_sb_mountdata sb_mntdata = {
2997                 .mntflags = flags,
2998         };
2999         int error;
3000
3001         dprintk("--> nfs4_xdev_mount()\n");
3002
3003         /* create a new volume representation */
3004         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
3005         if (IS_ERR(server)) {
3006                 error = PTR_ERR(server);
3007                 goto out_err_noserver;
3008         }
3009         sb_mntdata.server = server;
3010
3011         if (server->flags & NFS4_MOUNT_UNSHARED)
3012                 compare_super = NULL;
3013
3014         /* Get a superblock - note that we may end up sharing one that already exists */
3015         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3016         if (IS_ERR(s)) {
3017                 error = PTR_ERR(s);
3018                 goto out_err_nosb;
3019         }
3020
3021         if (s->s_fs_info != server) {
3022                 nfs_free_server(server);
3023                 server = NULL;
3024         } else {
3025                 error = nfs_bdi_register(server);
3026                 if (error)
3027                         goto error_splat_bdi;
3028         }
3029
3030         if (!s->s_root) {
3031                 /* initial superblock/root creation */
3032                 nfs4_clone_super(s, data->sb);
3033                 nfs_fscache_get_super_cookie(s, NULL, data);
3034         }
3035
3036         mntroot = nfs4_get_root(s, data->fh);
3037         if (IS_ERR(mntroot)) {
3038                 error = PTR_ERR(mntroot);
3039                 goto error_splat_super;
3040         }
3041         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3042                 dput(mntroot);
3043                 error = -ESTALE;
3044                 goto error_splat_super;
3045         }
3046
3047         s->s_flags |= MS_ACTIVE;
3048
3049         security_sb_clone_mnt_opts(data->sb, s);
3050
3051         dprintk("<-- nfs4_xdev_mount() = 0\n");
3052         return mntroot;
3053
3054 out_err_nosb:
3055         nfs_free_server(server);
3056 out_err_noserver:
3057         dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3058         return ERR_PTR(error);
3059
3060 error_splat_super:
3061         if (server && !s->s_root)
3062                 bdi_unregister(&server->backing_dev_info);
3063 error_splat_bdi:
3064         deactivate_locked_super(s);
3065         dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3066         return ERR_PTR(error);
3067 }
3068
3069 static struct dentry *
3070 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3071                            const char *dev_name, void *raw_data)
3072 {
3073         struct nfs_clone_mount *data = raw_data;
3074         struct super_block *s;
3075         struct nfs_server *server;
3076         struct dentry *mntroot;
3077         struct nfs_fh *mntfh;
3078         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3079         struct nfs_sb_mountdata sb_mntdata = {
3080                 .mntflags = flags,
3081         };
3082         int error = -ENOMEM;
3083
3084         dprintk("--> nfs4_referral_get_sb()\n");
3085
3086         mntfh = nfs_alloc_fhandle();
3087         if (mntfh == NULL)
3088                 goto out_err_nofh;
3089
3090         /* create a new volume representation */
3091         server = nfs4_create_referral_server(data, mntfh);
3092         if (IS_ERR(server)) {
3093                 error = PTR_ERR(server);
3094                 goto out_err_noserver;
3095         }
3096         sb_mntdata.server = server;
3097
3098         if (server->flags & NFS4_MOUNT_UNSHARED)
3099                 compare_super = NULL;
3100
3101         /* Get a superblock - note that we may end up sharing one that already exists */
3102         s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3103         if (IS_ERR(s)) {
3104                 error = PTR_ERR(s);
3105                 goto out_err_nosb;
3106         }
3107
3108         if (s->s_fs_info != server) {
3109                 nfs_free_server(server);
3110                 server = NULL;
3111         } else {
3112                 error = nfs_bdi_register(server);
3113                 if (error)
3114                         goto error_splat_bdi;
3115         }
3116
3117         if (!s->s_root) {
3118                 /* initial superblock/root creation */
3119                 nfs4_fill_super(s);
3120                 nfs_fscache_get_super_cookie(s, NULL, data);
3121         }
3122
3123         mntroot = nfs4_get_root(s, mntfh);
3124         if (IS_ERR(mntroot)) {
3125                 error = PTR_ERR(mntroot);
3126                 goto error_splat_super;
3127         }
3128         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3129                 dput(mntroot);
3130                 error = -ESTALE;
3131                 goto error_splat_super;
3132         }
3133
3134         s->s_flags |= MS_ACTIVE;
3135
3136         security_sb_clone_mnt_opts(data->sb, s);
3137
3138         nfs_free_fhandle(mntfh);
3139         dprintk("<-- nfs4_referral_get_sb() = 0\n");
3140         return mntroot;
3141
3142 out_err_nosb:
3143         nfs_free_server(server);
3144 out_err_noserver:
3145         nfs_free_fhandle(mntfh);
3146 out_err_nofh:
3147         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3148         return ERR_PTR(error);
3149
3150 error_splat_super:
3151         if (server && !s->s_root)
3152                 bdi_unregister(&server->backing_dev_info);
3153 error_splat_bdi:
3154         deactivate_locked_super(s);
3155         nfs_free_fhandle(mntfh);
3156         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3157         return ERR_PTR(error);
3158 }
3159
3160 /*
3161  * Create an NFS4 server record on referral traversal
3162  */
3163 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
3164                 int flags, const char *dev_name, void *raw_data,
3165                 struct vfsmount *mnt)
3166 {
3167         struct nfs_clone_mount *data = raw_data;
3168         char *export_path;
3169         struct vfsmount *root_mnt;
3170         int error;
3171
3172         dprintk("--> nfs4_referral_get_sb()\n");
3173
3174         export_path = data->mnt_path;
3175         data->mnt_path = "/";
3176
3177         root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3178                         flags, data, data->hostname);
3179         data->mnt_path = export_path;
3180
3181         error = PTR_ERR(root_mnt);
3182         if (IS_ERR(root_mnt))
3183                 goto out;
3184
3185         error = nfs_follow_remote_path(root_mnt, export_path, mnt);
3186 out:
3187         dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
3188                         error != 0 ? " [error]" : "");
3189         return error;
3190 }
3191
3192 #endif /* CONFIG_NFS_V4 */