fs/nfs/super.c

   1 /*
   2  *  linux/fs/nfs/super.c
   3  *
   4  *  Copyright (C) 1992  Rick Sladkey
   5  *
   6  *  nfs superblock handling functions
   7  *
   8  *  Modularised by Alan Cox <Alan.Cox@linux.org>, while hacking some
   9  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
  10  *
  11  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
  12  *  J.S.Peatfield@damtp.cam.ac.uk
  13  *
  14  *  Split from inode.c by David Howells <dhowells@redhat.com>
  15  *
  16  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
  17  *   particular server are held in the same superblock
  18  * - NFS superblocks can have several effective roots to the dentry tree
  19  * - directory type roots are spliced into the tree when a path from one root reaches the root
  20  *   of another (see nfs_lookup())
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25
  26 #include <linux/time.h>
  27 #include <linux/kernel.h>
  28 #include <linux/mm.h>
  29 #include <linux/string.h>
  30 #include <linux/stat.h>
  31 #include <linux/errno.h>
  32 #include <linux/unistd.h>
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/stats.h>
  35 #include <linux/sunrpc/metrics.h>
  36 #include <linux/sunrpc/xprtsock.h>
  37 #include <linux/sunrpc/xprtrdma.h>
  38 #include <linux/nfs_fs.h>
  39 #include <linux/nfs_mount.h>
  40 #include <linux/nfs4_mount.h>
  41 #include <linux/lockd/bind.h>
  42 #include <linux/smp_lock.h>
  43 #include <linux/seq_file.h>
  44 #include <linux/mount.h>
  45 #include <linux/nfs_idmap.h>
  46 #include <linux/vfs.h>
  47 #include <linux/inet.h>
  48 #include <linux/nfs_xdr.h>
  49 #include <linux/magic.h>
  50 #include <linux/parser.h>
  51
  52 #include <asm/system.h>
  53 #include <asm/uaccess.h>
  54
  55 #include "nfs4_fs.h"
  56 #include "callback.h"
  57 #include "delegation.h"
  58 #include "iostat.h"
  59 #include "internal.h"
  60
  61 #define NFSDBG_FACILITY         NFSDBG_VFS
  62
  63 enum {
  64         /* Mount options that take no arguments */
  65         Opt_soft, Opt_hard,
  66         Opt_intr, Opt_nointr,
  67         Opt_posix, Opt_noposix,
  68         Opt_cto, Opt_nocto,
  69         Opt_ac, Opt_noac,
  70         Opt_lock, Opt_nolock,
  71         Opt_v2, Opt_v3,
  72         Opt_udp, Opt_tcp, Opt_rdma,
  73         Opt_acl, Opt_noacl,
  74         Opt_rdirplus, Opt_nordirplus,
  75         Opt_sharecache, Opt_nosharecache,
  76
  77         /* Mount options that take integer arguments */
  78         Opt_port,
  79         Opt_rsize, Opt_wsize, Opt_bsize,
  80         Opt_timeo, Opt_retrans,
  81         Opt_acregmin, Opt_acregmax,
  82         Opt_acdirmin, Opt_acdirmax,
  83         Opt_actimeo,
  84         Opt_namelen,
  85         Opt_mountport,
  86         Opt_mountprog, Opt_mountvers,
  87         Opt_nfsprog, Opt_nfsvers,
  88
  89         /* Mount options that take string arguments */
  90         Opt_sec, Opt_proto, Opt_mountproto,
  91         Opt_addr, Opt_mountaddr, Opt_clientaddr,
  92
  93         /* Mount options that are ignored */
  94         Opt_userspace, Opt_deprecated,
  95
  96         Opt_err
  97 };
  98
  99 static match_table_t nfs_mount_option_tokens = {
 100         { Opt_userspace, "bg" },
 101         { Opt_userspace, "fg" },
 102         { Opt_soft, "soft" },
 103         { Opt_hard, "hard" },
 104         { Opt_intr, "intr" },
 105         { Opt_nointr, "nointr" },
 106         { Opt_posix, "posix" },
 107         { Opt_noposix, "noposix" },
 108         { Opt_cto, "cto" },
 109         { Opt_nocto, "nocto" },
 110         { Opt_ac, "ac" },
 111         { Opt_noac, "noac" },
 112         { Opt_lock, "lock" },
 113         { Opt_nolock, "nolock" },
 114         { Opt_v2, "v2" },
 115         { Opt_v3, "v3" },
 116         { Opt_udp, "udp" },
 117         { Opt_tcp, "tcp" },
 118         { Opt_rdma, "rdma" },
 119         { Opt_acl, "acl" },
 120         { Opt_noacl, "noacl" },
 121         { Opt_rdirplus, "rdirplus" },
 122         { Opt_nordirplus, "nordirplus" },
 123         { Opt_sharecache, "sharecache" },
 124         { Opt_nosharecache, "nosharecache" },
 125
 126         { Opt_port, "port=%u" },
 127         { Opt_rsize, "rsize=%u" },
 128         { Opt_wsize, "wsize=%u" },
 129         { Opt_bsize, "bsize=%u" },
 130         { Opt_timeo, "timeo=%u" },
 131         { Opt_retrans, "retrans=%u" },
 132         { Opt_acregmin, "acregmin=%u" },
 133         { Opt_acregmax, "acregmax=%u" },
 134         { Opt_acdirmin, "acdirmin=%u" },
 135         { Opt_acdirmax, "acdirmax=%u" },
 136         { Opt_actimeo, "actimeo=%u" },
 137         { Opt_userspace, "retry=%u" },
 138         { Opt_namelen, "namlen=%u" },
 139         { Opt_mountport, "mountport=%u" },
 140         { Opt_mountprog, "mountprog=%u" },
 141         { Opt_mountvers, "mountvers=%u" },
 142         { Opt_nfsprog, "nfsprog=%u" },
 143         { Opt_nfsvers, "nfsvers=%u" },
 144         { Opt_nfsvers, "vers=%u" },
 145
 146         { Opt_sec, "sec=%s" },
 147         { Opt_proto, "proto=%s" },
 148         { Opt_mountproto, "mountproto=%s" },
 149         { Opt_addr, "addr=%s" },
 150         { Opt_clientaddr, "clientaddr=%s" },
 151         { Opt_userspace, "mounthost=%s" },
 152         { Opt_mountaddr, "mountaddr=%s" },
 153
 154         { Opt_err, NULL }
 155 };
 156
 157 enum {
 158         Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
 159
 160         Opt_xprt_err
 161 };
 162
 163 static match_table_t nfs_xprt_protocol_tokens = {
 164         { Opt_xprt_udp, "udp" },
 165         { Opt_xprt_tcp, "tcp" },
 166         { Opt_xprt_rdma, "rdma" },
 167
 168         { Opt_xprt_err, NULL }
 169 };
 170
 171 enum {
 172         Opt_sec_none, Opt_sec_sys,
 173         Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
 174         Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
 175         Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
 176
 177         Opt_sec_err
 178 };
 179
 180 static match_table_t nfs_secflavor_tokens = {
 181         { Opt_sec_none, "none" },
 182         { Opt_sec_none, "null" },
 183         { Opt_sec_sys, "sys" },
 184
 185         { Opt_sec_krb5, "krb5" },
 186         { Opt_sec_krb5i, "krb5i" },
 187         { Opt_sec_krb5p, "krb5p" },
 188
 189         { Opt_sec_lkey, "lkey" },
 190         { Opt_sec_lkeyi, "lkeyi" },
 191         { Opt_sec_lkeyp, "lkeyp" },
 192
 193         { Opt_sec_err, NULL }
 194 };
 195
 196
 197 static void nfs_umount_begin(struct vfsmount *, int);
 198 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 199 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 200 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
 201 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
 202 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
 203                 int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 204 static void nfs_kill_super(struct super_block *);
 205
 206 static struct file_system_type nfs_fs_type = {
 207         .owner          = THIS_MODULE,
 208         .name           = "nfs",
 209         .get_sb         = nfs_get_sb,
 210         .kill_sb        = nfs_kill_super,
 211         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 212 };
 213
 214 struct file_system_type nfs_xdev_fs_type = {
 215         .owner          = THIS_MODULE,
 216         .name           = "nfs",
 217         .get_sb         = nfs_xdev_get_sb,
 218         .kill_sb        = nfs_kill_super,
 219         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 220 };
 221
 222 static const struct super_operations nfs_sops = {
 223         .alloc_inode    = nfs_alloc_inode,
 224         .destroy_inode  = nfs_destroy_inode,
 225         .write_inode    = nfs_write_inode,
 226         .statfs         = nfs_statfs,
 227         .clear_inode    = nfs_clear_inode,
 228         .umount_begin   = nfs_umount_begin,
 229         .show_options   = nfs_show_options,
 230         .show_stats     = nfs_show_stats,
 231 };
 232
 233 #ifdef CONFIG_NFS_V4
 234 static int nfs4_get_sb(struct file_system_type *fs_type,
 235         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 236 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
 237         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 238 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 239         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 240 static void nfs4_kill_super(struct super_block *sb);
 241
 242 static struct file_system_type nfs4_fs_type = {
 243         .owner          = THIS_MODULE,
 244         .name           = "nfs4",
 245         .get_sb         = nfs4_get_sb,
 246         .kill_sb        = nfs4_kill_super,
 247         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 248 };
 249
 250 struct file_system_type nfs4_xdev_fs_type = {
 251         .owner          = THIS_MODULE,
 252         .name           = "nfs4",
 253         .get_sb         = nfs4_xdev_get_sb,
 254         .kill_sb        = nfs4_kill_super,
 255         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 256 };
 257
 258 struct file_system_type nfs4_referral_fs_type = {
 259         .owner          = THIS_MODULE,
 260         .name           = "nfs4",
 261         .get_sb         = nfs4_referral_get_sb,
 262         .kill_sb        = nfs4_kill_super,
 263         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 264 };
 265
 266 static const struct super_operations nfs4_sops = {
 267         .alloc_inode    = nfs_alloc_inode,
 268         .destroy_inode  = nfs_destroy_inode,
 269         .write_inode    = nfs_write_inode,
 270         .statfs         = nfs_statfs,
 271         .clear_inode    = nfs4_clear_inode,
 272         .umount_begin   = nfs_umount_begin,
 273         .show_options   = nfs_show_options,
 274         .show_stats     = nfs_show_stats,
 275 };
 276 #endif
 277
 278 static struct shrinker acl_shrinker = {
 279         .shrink         = nfs_access_cache_shrinker,
 280         .seeks          = DEFAULT_SEEKS,
 281 };
 282
 283 /*
 284  * Register the NFS filesystems
 285  */
 286 int __init register_nfs_fs(void)
 287 {
 288         int ret;
 289
 290         ret = register_filesystem(&nfs_fs_type);
 291         if (ret < 0)
 292                 goto error_0;
 293
 294         ret = nfs_register_sysctl();
 295         if (ret < 0)
 296                 goto error_1;
 297 #ifdef CONFIG_NFS_V4
 298         ret = register_filesystem(&nfs4_fs_type);
 299         if (ret < 0)
 300                 goto error_2;
 301 #endif
 302         register_shrinker(&acl_shrinker);
 303         return 0;
 304
 305 #ifdef CONFIG_NFS_V4
 306 error_2:
 307         nfs_unregister_sysctl();
 308 #endif
 309 error_1:
 310         unregister_filesystem(&nfs_fs_type);
 311 error_0:
 312         return ret;
 313 }
 314
 315 /*
 316  * Unregister the NFS filesystems
 317  */
 318 void __exit unregister_nfs_fs(void)
 319 {
 320         unregister_shrinker(&acl_shrinker);
 321 #ifdef CONFIG_NFS_V4
 322         unregister_filesystem(&nfs4_fs_type);
 323 #endif
 324         nfs_unregister_sysctl();
 325         unregister_filesystem(&nfs_fs_type);
 326 }
 327
 328 /*
 329  * Deliver file system statistics to userspace
 330  */
 331 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 332 {
 333         struct nfs_server *server = NFS_SB(dentry->d_sb);
 334         unsigned char blockbits;
 335         unsigned long blockres;
 336         struct nfs_fh *fh = NFS_FH(dentry->d_inode);
 337         struct nfs_fattr fattr;
 338         struct nfs_fsstat res = {
 339                         .fattr = &fattr,
 340         };
 341         int error;
 342
 343         lock_kernel();
 344
 345         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 346         if (error < 0)
 347                 goto out_err;
 348         buf->f_type = NFS_SUPER_MAGIC;
 349
 350         /*
 351          * Current versions of glibc do not correctly handle the
 352          * case where f_frsize != f_bsize.  Eventually we want to
 353          * report the value of wtmult in this field.
 354          */
 355         buf->f_frsize = dentry->d_sb->s_blocksize;
 356
 357         /*
 358          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 359          * are reported in units of f_frsize.  Linux hasn't had
 360          * an f_frsize field in its statfs struct until recently,
 361          * thus historically Linux's sys_statfs reports these
 362          * fields in units of f_bsize.
 363          */
 364         buf->f_bsize = dentry->d_sb->s_blocksize;
 365         blockbits = dentry->d_sb->s_blocksize_bits;
 366         blockres = (1 << blockbits) - 1;
 367         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 368         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 369         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 370
 371         buf->f_files = res.tfiles;
 372         buf->f_ffree = res.afiles;
 373
 374         buf->f_namelen = server->namelen;
 375
 376         unlock_kernel();
 377         return 0;
 378
 379  out_err:
 380         dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
 381         unlock_kernel();
 382         return error;
 383 }
 384
 385 /*
 386  * Map the security flavour number to a name
 387  */
 388 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 389 {
 390         static const struct {
 391                 rpc_authflavor_t flavour;
 392                 const char *str;
 393         } sec_flavours[] = {
 394                 { RPC_AUTH_NULL, "null" },
 395                 { RPC_AUTH_UNIX, "sys" },
 396                 { RPC_AUTH_GSS_KRB5, "krb5" },
 397                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 398                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 399                 { RPC_AUTH_GSS_LKEY, "lkey" },
 400                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 401                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 402                 { RPC_AUTH_GSS_SPKM, "spkm" },
 403                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 404                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 405                 { UINT_MAX, "unknown" }
 406         };
 407         int i;
 408
 409         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 410                 if (sec_flavours[i].flavour == flavour)
 411                         break;
 412         }
 413         return sec_flavours[i].str;
 414 }
 415
 416 /*
 417  * Describe the mount options in force on this server representation
 418  */
 419 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
 420 {
 421         static const struct proc_nfs_info {
 422                 int flag;
 423                 const char *str;
 424                 const char *nostr;
 425         } nfs_info[] = {
 426                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 427                 { NFS_MOUNT_INTR, ",intr", "" },
 428                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 429                 { NFS_MOUNT_NOAC, ",noac", "" },
 430                 { NFS_MOUNT_NONLM, ",nolock", "" },
 431                 { NFS_MOUNT_NOACL, ",noacl", "" },
 432                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 433                 { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
 434                 { 0, NULL, NULL }
 435         };
 436         const struct proc_nfs_info *nfs_infop;
 437         struct nfs_client *clp = nfss->nfs_client;
 438
 439         seq_printf(m, ",vers=%d", clp->rpc_ops->version);
 440         seq_printf(m, ",rsize=%d", nfss->rsize);
 441         seq_printf(m, ",wsize=%d", nfss->wsize);
 442         if (nfss->acregmin != 3*HZ || showdefaults)
 443                 seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
 444         if (nfss->acregmax != 60*HZ || showdefaults)
 445                 seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
 446         if (nfss->acdirmin != 30*HZ || showdefaults)
 447                 seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
 448         if (nfss->acdirmax != 60*HZ || showdefaults)
 449                 seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
 450         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 451                 if (nfss->flags & nfs_infop->flag)
 452                         seq_puts(m, nfs_infop->str);
 453                 else
 454                         seq_puts(m, nfs_infop->nostr);
 455         }
 456         seq_printf(m, ",proto=%s",
 457                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
 458         seq_printf(m, ",timeo=%lu", 10U * clp->retrans_timeo / HZ);
 459         seq_printf(m, ",retrans=%u", clp->retrans_count);
 460         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 461 }
 462
 463 /*
 464  * Describe the mount options on this VFS mountpoint
 465  */
 466 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 467 {
 468         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 469
 470         nfs_show_mount_options(m, nfss, 0);
 471
 472         seq_printf(m, ",addr="NIPQUAD_FMT,
 473                 NIPQUAD(nfss->nfs_client->cl_addr.sin_addr));
 474
 475         return 0;
 476 }
 477
 478 /*
 479  * Present statistical information for this VFS mountpoint
 480  */
 481 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 482 {
 483         int i, cpu;
 484         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 485         struct rpc_auth *auth = nfss->client->cl_auth;
 486         struct nfs_iostats totals = { };
 487
 488         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 489
 490         /*
 491          * Display all mount option settings
 492          */
 493         seq_printf(m, "\n\topts:\t");
 494         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 495         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 496         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 497         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 498         nfs_show_mount_options(m, nfss, 1);
 499
 500         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 501
 502         seq_printf(m, "\n\tcaps:\t");
 503         seq_printf(m, "caps=0x%x", nfss->caps);
 504         seq_printf(m, ",wtmult=%d", nfss->wtmult);
 505         seq_printf(m, ",dtsize=%d", nfss->dtsize);
 506         seq_printf(m, ",bsize=%d", nfss->bsize);
 507         seq_printf(m, ",namelen=%d", nfss->namelen);
 508
 509 #ifdef CONFIG_NFS_V4
 510         if (nfss->nfs_client->cl_nfsversion == 4) {
 511                 seq_printf(m, "\n\tnfsv4:\t");
 512                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 513                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 514                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 515         }
 516 #endif
 517
 518         /*
 519          * Display security flavor in effect for this mount
 520          */
 521         seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
 522         if (auth->au_flavor)
 523                 seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
 524
 525         /*
 526          * Display superblock I/O counters
 527          */
 528         for_each_possible_cpu(cpu) {
 529                 struct nfs_iostats *stats;
 530
 531                 preempt_disable();
 532                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 533
 534                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 535                         totals.events[i] += stats->events[i];
 536                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 537                         totals.bytes[i] += stats->bytes[i];
 538
 539                 preempt_enable();
 540         }
 541
 542         seq_printf(m, "\n\tevents:\t");
 543         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 544                 seq_printf(m, "%lu ", totals.events[i]);
 545         seq_printf(m, "\n\tbytes:\t");
 546         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 547                 seq_printf(m, "%Lu ", totals.bytes[i]);
 548         seq_printf(m, "\n");
 549
 550         rpc_print_iostats(m, nfss->client);
 551
 552         return 0;
 553 }
 554
 555 /*
 556  * Begin unmount by attempting to remove all automounted mountpoints we added
 557  * in response to xdev traversals and referrals
 558  */
 559 static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
 560 {
 561         struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
 562         struct rpc_clnt *rpc;
 563
 564         shrink_submounts(vfsmnt, &nfs_automount_list);
 565
 566         if (!(flags & MNT_FORCE))
 567                 return;
 568         /* -EIO all pending I/O */
 569         rpc = server->client_acl;
 570         if (!IS_ERR(rpc))
 571                 rpc_killall_tasks(rpc);
 572         rpc = server->client;
 573         if (!IS_ERR(rpc))
 574                 rpc_killall_tasks(rpc);
 575 }
 576
 577 /*
 578  * Sanity-check a server address provided by the mount command
 579  */
 580 static int nfs_verify_server_address(struct sockaddr *addr)
 581 {
 582         switch (addr->sa_family) {
 583         case AF_INET: {
 584                 struct sockaddr_in *sa = (struct sockaddr_in *) addr;
 585                 if (sa->sin_addr.s_addr != INADDR_ANY)
 586                         return 1;
 587                 break;
 588         }
 589         }
 590
 591         return 0;
 592 }
 593
 594 /*
 595  * Error-check and convert a string of mount options from user space into
 596  * a data structure
 597  */
 598 static int nfs_parse_mount_options(char *raw,
 599                                    struct nfs_parsed_mount_data *mnt)
 600 {
 601         char *p, *string;
 602
 603         if (!raw) {
 604                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 605                 return 1;
 606         }
 607         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 608
 609         while ((p = strsep(&raw, ",")) != NULL) {
 610                 substring_t args[MAX_OPT_ARGS];
 611                 int option, token;
 612
 613                 if (!*p)
 614                         continue;
 615
 616                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
 617
 618                 token = match_token(p, nfs_mount_option_tokens, args);
 619                 switch (token) {
 620                 case Opt_soft:
 621                         mnt->flags |= NFS_MOUNT_SOFT;
 622                         break;
 623                 case Opt_hard:
 624                         mnt->flags &= ~NFS_MOUNT_SOFT;
 625                         break;
 626                 case Opt_intr:
 627                         mnt->flags |= NFS_MOUNT_INTR;
 628                         break;
 629                 case Opt_nointr:
 630                         mnt->flags &= ~NFS_MOUNT_INTR;
 631                         break;
 632                 case Opt_posix:
 633                         mnt->flags |= NFS_MOUNT_POSIX;
 634                         break;
 635                 case Opt_noposix:
 636                         mnt->flags &= ~NFS_MOUNT_POSIX;
 637                         break;
 638                 case Opt_cto:
 639                         mnt->flags &= ~NFS_MOUNT_NOCTO;
 640                         break;
 641                 case Opt_nocto:
 642                         mnt->flags |= NFS_MOUNT_NOCTO;
 643                         break;
 644                 case Opt_ac:
 645                         mnt->flags &= ~NFS_MOUNT_NOAC;
 646                         break;
 647                 case Opt_noac:
 648                         mnt->flags |= NFS_MOUNT_NOAC;
 649                         break;
 650                 case Opt_lock:
 651                         mnt->flags &= ~NFS_MOUNT_NONLM;
 652                         break;
 653                 case Opt_nolock:
 654                         mnt->flags |= NFS_MOUNT_NONLM;
 655                         break;
 656                 case Opt_v2:
 657                         mnt->flags &= ~NFS_MOUNT_VER3;
 658                         break;
 659                 case Opt_v3:
 660                         mnt->flags |= NFS_MOUNT_VER3;
 661                         break;
 662                 case Opt_udp:
 663                         mnt->flags &= ~NFS_MOUNT_TCP;
 664                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 665                         mnt->timeo = 7;
 666                         mnt->retrans = 5;
 667                         break;
 668                 case Opt_tcp:
 669                         mnt->flags |= NFS_MOUNT_TCP;
 670                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 671                         mnt->timeo = 600;
 672                         mnt->retrans = 2;
 673                         break;
 674                 case Opt_rdma:
 675                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
 676                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
 677                         mnt->timeo = 600;
 678                         mnt->retrans = 2;
 679                         break;
 680                 case Opt_acl:
 681                         mnt->flags &= ~NFS_MOUNT_NOACL;
 682                         break;
 683                 case Opt_noacl:
 684                         mnt->flags |= NFS_MOUNT_NOACL;
 685                         break;
 686                 case Opt_rdirplus:
 687                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
 688                         break;
 689                 case Opt_nordirplus:
 690                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
 691                         break;
 692                 case Opt_sharecache:
 693                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
 694                         break;
 695                 case Opt_nosharecache:
 696                         mnt->flags |= NFS_MOUNT_UNSHARED;
 697                         break;
 698
 699                 case Opt_port:
 700                         if (match_int(args, &option))
 701                                 return 0;
 702                         if (option < 0 || option > 65535)
 703                                 return 0;
 704                         mnt->nfs_server.address.sin_port = htons(option);
 705                         break;
 706                 case Opt_rsize:
 707                         if (match_int(args, &mnt->rsize))
 708                                 return 0;
 709                         break;
 710                 case Opt_wsize:
 711                         if (match_int(args, &mnt->wsize))
 712                                 return 0;
 713                         break;
 714                 case Opt_bsize:
 715                         if (match_int(args, &option))
 716                                 return 0;
 717                         if (option < 0)
 718                                 return 0;
 719                         mnt->bsize = option;
 720                         break;
 721                 case Opt_timeo:
 722                         if (match_int(args, &mnt->timeo))
 723                                 return 0;
 724                         break;
 725                 case Opt_retrans:
 726                         if (match_int(args, &mnt->retrans))
 727                                 return 0;
 728                         break;
 729                 case Opt_acregmin:
 730                         if (match_int(args, &mnt->acregmin))
 731                                 return 0;
 732                         break;
 733                 case Opt_acregmax:
 734                         if (match_int(args, &mnt->acregmax))
 735                                 return 0;
 736                         break;
 737                 case Opt_acdirmin:
 738                         if (match_int(args, &mnt->acdirmin))
 739                                 return 0;
 740                         break;
 741                 case Opt_acdirmax:
 742                         if (match_int(args, &mnt->acdirmax))
 743                                 return 0;
 744                         break;
 745                 case Opt_actimeo:
 746                         if (match_int(args, &option))
 747                                 return 0;
 748                         if (option < 0)
 749                                 return 0;
 750                         mnt->acregmin =
 751                         mnt->acregmax =
 752                         mnt->acdirmin =
 753                         mnt->acdirmax = option;
 754                         break;
 755                 case Opt_namelen:
 756                         if (match_int(args, &mnt->namlen))
 757                                 return 0;
 758                         break;
 759                 case Opt_mountport:
 760                         if (match_int(args, &option))
 761                                 return 0;
 762                         if (option < 0 || option > 65535)
 763                                 return 0;
 764                         mnt->mount_server.port = option;
 765                         break;
 766                 case Opt_mountprog:
 767                         if (match_int(args, &option))
 768                                 return 0;
 769                         if (option < 0)
 770                                 return 0;
 771                         mnt->mount_server.program = option;
 772                         break;
 773                 case Opt_mountvers:
 774                         if (match_int(args, &option))
 775                                 return 0;
 776                         if (option < 0)
 777                                 return 0;
 778                         mnt->mount_server.version = option;
 779                         break;
 780                 case Opt_nfsprog:
 781                         if (match_int(args, &option))
 782                                 return 0;
 783                         if (option < 0)
 784                                 return 0;
 785                         mnt->nfs_server.program = option;
 786                         break;
 787                 case Opt_nfsvers:
 788                         if (match_int(args, &option))
 789                                 return 0;
 790                         switch (option) {
 791                         case 2:
 792                                 mnt->flags &= ~NFS_MOUNT_VER3;
 793                                 break;
 794                         case 3:
 795                                 mnt->flags |= NFS_MOUNT_VER3;
 796                                 break;
 797                         default:
 798                                 goto out_unrec_vers;
 799                         }
 800                         break;
 801
 802                 case Opt_sec:
 803                         string = match_strdup(args);
 804                         if (string == NULL)
 805                                 goto out_nomem;
 806                         token = match_token(string, nfs_secflavor_tokens, args);
 807                         kfree(string);
 808
 809                         /*
 810                          * The flags setting is for v2/v3.  The flavor_len
 811                          * setting is for v4.  v2/v3 also need to know the
 812                          * difference between NULL and UNIX.
 813                          */
 814                         switch (token) {
 815                         case Opt_sec_none:
 816                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 817                                 mnt->auth_flavor_len = 0;
 818                                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 819                                 break;
 820                         case Opt_sec_sys:
 821                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 822                                 mnt->auth_flavor_len = 0;
 823                                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 824                                 break;
 825                         case Opt_sec_krb5:
 826                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 827                                 mnt->auth_flavor_len = 1;
 828                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 829                                 break;
 830                         case Opt_sec_krb5i:
 831                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 832                                 mnt->auth_flavor_len = 1;
 833                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 834                                 break;
 835                         case Opt_sec_krb5p:
 836                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 837                                 mnt->auth_flavor_len = 1;
 838                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 839                                 break;
 840                         case Opt_sec_lkey:
 841                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 842                                 mnt->auth_flavor_len = 1;
 843                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 844                                 break;
 845                         case Opt_sec_lkeyi:
 846                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 847                                 mnt->auth_flavor_len = 1;
 848                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 849                                 break;
 850                         case Opt_sec_lkeyp:
 851                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 852                                 mnt->auth_flavor_len = 1;
 853                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 854                                 break;
 855                         case Opt_sec_spkm:
 856                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 857                                 mnt->auth_flavor_len = 1;
 858                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 859                                 break;
 860                         case Opt_sec_spkmi:
 861                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 862                                 mnt->auth_flavor_len = 1;
 863                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 864                                 break;
 865                         case Opt_sec_spkmp:
 866                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 867                                 mnt->auth_flavor_len = 1;
 868                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 869                                 break;
 870                         default:
 871                                 goto out_unrec_sec;
 872                         }
 873                         break;
 874                 case Opt_proto:
 875                         string = match_strdup(args);
 876                         if (string == NULL)
 877                                 goto out_nomem;
 878                         token = match_token(string,
 879                                             nfs_xprt_protocol_tokens, args);
 880                         kfree(string);
 881
 882                         switch (token) {
 883                         case Opt_xprt_udp:
 884                                 mnt->flags &= ~NFS_MOUNT_TCP;
 885                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 886                                 mnt->timeo = 7;
 887                                 mnt->retrans = 5;
 888                                 break;
 889                         case Opt_xprt_tcp:
 890                                 mnt->flags |= NFS_MOUNT_TCP;
 891                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 892                                 mnt->timeo = 600;
 893                                 mnt->retrans = 2;
 894                                 break;
 895                         case Opt_xprt_rdma:
 896                                 /* vector side protocols to TCP */
 897                                 mnt->flags |= NFS_MOUNT_TCP;
 898                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
 899                                 mnt->timeo = 600;
 900                                 mnt->retrans = 2;
 901                                 break;
 902                         default:
 903                                 goto out_unrec_xprt;
 904                         }
 905                         break;
 906                 case Opt_mountproto:
 907                         string = match_strdup(args);
 908                         if (string == NULL)
 909                                 goto out_nomem;
 910                         token = match_token(string,
 911                                             nfs_xprt_protocol_tokens, args);
 912                         kfree(string);
 913
 914                         switch (token) {
 915                         case Opt_xprt_udp:
 916                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 917                                 break;
 918                         case Opt_xprt_tcp:
 919                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 920                                 break;
 921                         case Opt_xprt_rdma: /* not used for side protocols */
 922                         default:
 923                                 goto out_unrec_xprt;
 924                         }
 925                         break;
 926                 case Opt_addr:
 927                         string = match_strdup(args);
 928                         if (string == NULL)
 929                                 goto out_nomem;
 930                         mnt->nfs_server.address.sin_family = AF_INET;
 931                         mnt->nfs_server.address.sin_addr.s_addr =
 932                                                         in_aton(string);
 933                         kfree(string);
 934                         break;
 935                 case Opt_clientaddr:
 936                         string = match_strdup(args);
 937                         if (string == NULL)
 938                                 goto out_nomem;
 939                         mnt->client_address = string;
 940                         break;
 941                 case Opt_mountaddr:
 942                         string = match_strdup(args);
 943                         if (string == NULL)
 944                                 goto out_nomem;
 945                         mnt->mount_server.address.sin_family = AF_INET;
 946                         mnt->mount_server.address.sin_addr.s_addr =
 947                                                         in_aton(string);
 948                         kfree(string);
 949                         break;
 950
 951                 case Opt_userspace:
 952                 case Opt_deprecated:
 953                         break;
 954
 955                 default:
 956                         goto out_unknown;
 957                 }
 958         }
 959
 960         return 1;
 961
 962 out_nomem:
 963         printk(KERN_INFO "NFS: not enough memory to parse option\n");
 964         return 0;
 965
 966 out_unrec_vers:
 967         printk(KERN_INFO "NFS: unrecognized NFS version number\n");
 968         return 0;
 969
 970 out_unrec_xprt:
 971         printk(KERN_INFO "NFS: unrecognized transport protocol\n");
 972         return 0;
 973
 974 out_unrec_sec:
 975         printk(KERN_INFO "NFS: unrecognized security flavor\n");
 976         return 0;
 977
 978 out_unknown:
 979         printk(KERN_INFO "NFS: unknown mount option: %s\n", p);
 980         return 0;
 981 }
 982
 983 /*
 984  * Use the remote server's MOUNT service to request the NFS file handle
 985  * corresponding to the provided path.
 986  */
 987 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
 988                          struct nfs_fh *root_fh)
 989 {
 990         struct sockaddr_in sin;
 991         int status;
 992
 993         if (args->mount_server.version == 0) {
 994                 if (args->flags & NFS_MOUNT_VER3)
 995                         args->mount_server.version = NFS_MNT3_VERSION;
 996                 else
 997                         args->mount_server.version = NFS_MNT_VERSION;
 998         }
 999
1000         /*
1001          * Construct the mount server's address.
1002          */
1003         if (args->mount_server.address.sin_addr.s_addr != INADDR_ANY)
1004                 sin = args->mount_server.address;
1005         else
1006                 sin = args->nfs_server.address;
1007         /*
1008          * autobind will be used if mount_server.port == 0
1009          */
1010         sin.sin_port = htons(args->mount_server.port);
1011
1012         /*
1013          * Now ask the mount server to map our export path
1014          * to a file handle.
1015          */
1016         status = nfs_mount((struct sockaddr *) &sin,
1017                            sizeof(sin),
1018                            args->nfs_server.hostname,
1019                            args->nfs_server.export_path,
1020                            args->mount_server.version,
1021                            args->mount_server.protocol,
1022                            root_fh);
1023         if (status == 0)
1024                 return 0;
1025
1026         dfprintk(MOUNT, "NFS: unable to mount server " NIPQUAD_FMT
1027                         ", error %d\n", NIPQUAD(sin.sin_addr.s_addr), status);
1028         return status;
1029 }
1030
1031 /*
1032  * Validate the NFS2/NFS3 mount data
1033  * - fills in the mount root filehandle
1034  *
1035  * For option strings, user space handles the following behaviors:
1036  *
1037  * + DNS: mapping server host name to IP address ("addr=" option)
1038  *
1039  * + failure mode: how to behave if a mount request can't be handled
1040  *   immediately ("fg/bg" option)
1041  *
1042  * + retry: how often to retry a mount request ("retry=" option)
1043  *
1044  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1045  *   mountproto=tcp after mountproto=udp, and so on
1046  *
1047  * XXX: as far as I can tell, changing the NFS program number is not
1048  *      supported in the NFS client.
1049  */
1050 static int nfs_validate_mount_data(void *options,
1051                                    struct nfs_parsed_mount_data *args,
1052                                    struct nfs_fh *mntfh,
1053                                    const char *dev_name)
1054 {
1055         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1056
1057         if (data == NULL)
1058                 goto out_no_data;
1059
1060         memset(args, 0, sizeof(*args));
1061         args->flags             = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1062         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1063         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1064         args->timeo             = 600;
1065         args->retrans           = 2;
1066         args->acregmin          = 3;
1067         args->acregmax          = 60;
1068         args->acdirmin          = 30;
1069         args->acdirmax          = 60;
1070         args->mount_server.protocol = XPRT_TRANSPORT_UDP;
1071         args->mount_server.program = NFS_MNT_PROGRAM;
1072         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1073         args->nfs_server.program = NFS_PROGRAM;
1074
1075         switch (data->version) {
1076         case 1:
1077                 data->namlen = 0;
1078         case 2:
1079                 data->bsize = 0;
1080         case 3:
1081                 if (data->flags & NFS_MOUNT_VER3)
1082                         goto out_no_v3;
1083                 data->root.size = NFS2_FHSIZE;
1084                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1085         case 4:
1086                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1087                         goto out_no_sec;
1088         case 5:
1089                 memset(data->context, 0, sizeof(data->context));
1090         case 6:
1091                 if (data->flags & NFS_MOUNT_VER3)
1092                         mntfh->size = data->root.size;
1093                 else
1094                         mntfh->size = NFS2_FHSIZE;
1095
1096                 if (mntfh->size > sizeof(mntfh->data))
1097                         goto out_invalid_fh;
1098
1099                 memcpy(mntfh->data, data->root.data, mntfh->size);
1100                 if (mntfh->size < sizeof(mntfh->data))
1101                         memset(mntfh->data + mntfh->size, 0,
1102                                sizeof(mntfh->data) - mntfh->size);
1103                 /*
1104                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1105                  * can deal with.
1106                  */
1107                 args->flags             = data->flags;
1108                 args->rsize             = data->rsize;
1109                 args->wsize             = data->wsize;
1110                 args->flags             = data->flags;
1111                 args->timeo             = data->timeo;
1112                 args->retrans           = data->retrans;
1113                 args->acregmin          = data->acregmin;
1114                 args->acregmax          = data->acregmax;
1115                 args->acdirmin          = data->acdirmin;
1116                 args->acdirmax          = data->acdirmax;
1117                 args->nfs_server.address = data->addr;
1118                 if (!(data->flags & NFS_MOUNT_TCP))
1119                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1120                 /* N.B. caller will free nfs_server.hostname in all cases */
1121                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1122                 args->namlen            = data->namlen;
1123                 args->bsize             = data->bsize;
1124                 args->auth_flavors[0]   = data->pseudoflavor;
1125                 break;
1126         default: {
1127                 unsigned int len;
1128                 char *c;
1129                 int status;
1130
1131                 if (nfs_parse_mount_options((char *)options, args) == 0)
1132                         return -EINVAL;
1133
1134                 c = strchr(dev_name, ':');
1135                 if (c == NULL)
1136                         return -EINVAL;
1137                 len = c - dev_name;
1138                 /* N.B. caller will free nfs_server.hostname in all cases */
1139                 args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
1140
1141                 c++;
1142                 if (strlen(c) > NFS_MAXPATHLEN)
1143                         return -ENAMETOOLONG;
1144                 args->nfs_server.export_path = c;
1145
1146                 status = nfs_try_mount(args, mntfh);
1147                 if (status)
1148                         return status;
1149
1150                 break;
1151                 }
1152         }
1153
1154         if (!(args->flags & NFS_MOUNT_SECFLAVOUR))
1155                 args->auth_flavors[0] = RPC_AUTH_UNIX;
1156
1157 #ifndef CONFIG_NFS_V3
1158         if (args->flags & NFS_MOUNT_VER3)
1159                 goto out_v3_not_compiled;
1160 #endif /* !CONFIG_NFS_V3 */
1161
1162         if (!nfs_verify_server_address((struct sockaddr *)
1163                                                 &args->nfs_server.address))
1164                 goto out_no_address;
1165
1166         return 0;
1167
1168 out_no_data:
1169         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1170         return -EINVAL;
1171
1172 out_no_v3:
1173         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1174                  data->version);
1175         return -EINVAL;
1176
1177 out_no_sec:
1178         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1179         return -EINVAL;
1180
1181 #ifndef CONFIG_NFS_V3
1182 out_v3_not_compiled:
1183         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1184         return -EPROTONOSUPPORT;
1185 #endif /* !CONFIG_NFS_V3 */
1186
1187 out_no_address:
1188         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1189         return -EINVAL;
1190
1191 out_invalid_fh:
1192         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1193         return -EINVAL;
1194 }
1195
1196 /*
1197  * Initialise the common bits of the superblock
1198  */
1199 static inline void nfs_initialise_sb(struct super_block *sb)
1200 {
1201         struct nfs_server *server = NFS_SB(sb);
1202
1203         sb->s_magic = NFS_SUPER_MAGIC;
1204
1205         /* We probably want something more informative here */
1206         snprintf(sb->s_id, sizeof(sb->s_id),
1207                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1208
1209         if (sb->s_blocksize == 0)
1210                 sb->s_blocksize = nfs_block_bits(server->wsize,
1211                                                  &sb->s_blocksize_bits);
1212
1213         if (server->flags & NFS_MOUNT_NOAC)
1214                 sb->s_flags |= MS_SYNCHRONOUS;
1215
1216         nfs_super_set_maxbytes(sb, server->maxfilesize);
1217 }
1218
1219 /*
1220  * Finish setting up an NFS2/3 superblock
1221  */
1222 static void nfs_fill_super(struct super_block *sb,
1223                            struct nfs_parsed_mount_data *data)
1224 {
1225         struct nfs_server *server = NFS_SB(sb);
1226
1227         sb->s_blocksize_bits = 0;
1228         sb->s_blocksize = 0;
1229         if (data->bsize)
1230                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1231
1232         if (server->flags & NFS_MOUNT_VER3) {
1233                 /* The VFS shouldn't apply the umask to mode bits. We will do
1234                  * so ourselves when necessary.
1235                  */
1236                 sb->s_flags |= MS_POSIXACL;
1237                 sb->s_time_gran = 1;
1238         }
1239
1240         sb->s_op = &nfs_sops;
1241         nfs_initialise_sb(sb);
1242 }
1243
1244 /*
1245  * Finish setting up a cloned NFS2/3 superblock
1246  */
1247 static void nfs_clone_super(struct super_block *sb,
1248                             const struct super_block *old_sb)
1249 {
1250         struct nfs_server *server = NFS_SB(sb);
1251
1252         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1253         sb->s_blocksize = old_sb->s_blocksize;
1254         sb->s_maxbytes = old_sb->s_maxbytes;
1255
1256         if (server->flags & NFS_MOUNT_VER3) {
1257                 /* The VFS shouldn't apply the umask to mode bits. We will do
1258                  * so ourselves when necessary.
1259                  */
1260                 sb->s_flags |= MS_POSIXACL;
1261                 sb->s_time_gran = 1;
1262         }
1263
1264         sb->s_op = old_sb->s_op;
1265         nfs_initialise_sb(sb);
1266 }
1267
1268 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1269
1270 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1271 {
1272         const struct nfs_server *a = s->s_fs_info;
1273         const struct rpc_clnt *clnt_a = a->client;
1274         const struct rpc_clnt *clnt_b = b->client;
1275
1276         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1277                 goto Ebusy;
1278         if (a->nfs_client != b->nfs_client)
1279                 goto Ebusy;
1280         if (a->flags != b->flags)
1281                 goto Ebusy;
1282         if (a->wsize != b->wsize)
1283                 goto Ebusy;
1284         if (a->rsize != b->rsize)
1285                 goto Ebusy;
1286         if (a->acregmin != b->acregmin)
1287                 goto Ebusy;
1288         if (a->acregmax != b->acregmax)
1289                 goto Ebusy;
1290         if (a->acdirmin != b->acdirmin)
1291                 goto Ebusy;
1292         if (a->acdirmax != b->acdirmax)
1293                 goto Ebusy;
1294         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1295                 goto Ebusy;
1296         return 1;
1297 Ebusy:
1298         return 0;
1299 }
1300
1301 struct nfs_sb_mountdata {
1302         struct nfs_server *server;
1303         int mntflags;
1304 };
1305
1306 static int nfs_set_super(struct super_block *s, void *data)
1307 {
1308         struct nfs_sb_mountdata *sb_mntdata = data;
1309         struct nfs_server *server = sb_mntdata->server;
1310         int ret;
1311
1312         s->s_flags = sb_mntdata->mntflags;
1313         s->s_fs_info = server;
1314         ret = set_anon_super(s, server);
1315         if (ret == 0)
1316                 server->s_dev = s->s_dev;
1317         return ret;
1318 }
1319
1320 static int nfs_compare_super(struct super_block *sb, void *data)
1321 {
1322         struct nfs_sb_mountdata *sb_mntdata = data;
1323         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1324         int mntflags = sb_mntdata->mntflags;
1325
1326         if (memcmp(&old->nfs_client->cl_addr,
1327                                 &server->nfs_client->cl_addr,
1328                                 sizeof(old->nfs_client->cl_addr)) != 0)
1329                 return 0;
1330         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1331         if (old->flags & NFS_MOUNT_UNSHARED)
1332                 return 0;
1333         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1334                 return 0;
1335         return nfs_compare_mount_options(sb, server, mntflags);
1336 }
1337
1338 static int nfs_get_sb(struct file_system_type *fs_type,
1339         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1340 {
1341         struct nfs_server *server = NULL;
1342         struct super_block *s;
1343         struct nfs_fh mntfh;
1344         struct nfs_parsed_mount_data data;
1345         struct dentry *mntroot;
1346         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1347         struct nfs_sb_mountdata sb_mntdata = {
1348                 .mntflags = flags,
1349         };
1350         int error;
1351
1352         /* Validate the mount data */
1353         error = nfs_validate_mount_data(raw_data, &data, &mntfh, dev_name);
1354         if (error < 0)
1355                 goto out;
1356
1357         /* Get a volume representation */
1358         server = nfs_create_server(&data, &mntfh);
1359         if (IS_ERR(server)) {
1360                 error = PTR_ERR(server);
1361                 goto out;
1362         }
1363         sb_mntdata.server = server;
1364
1365         if (server->flags & NFS_MOUNT_UNSHARED)
1366                 compare_super = NULL;
1367
1368         /* Get a superblock - note that we may end up sharing one that already exists */
1369         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1370         if (IS_ERR(s)) {
1371                 error = PTR_ERR(s);
1372                 goto out_err_nosb;
1373         }
1374
1375         if (s->s_fs_info != server) {
1376                 nfs_free_server(server);
1377                 server = NULL;
1378         }
1379
1380         if (!s->s_root) {
1381                 /* initial superblock/root creation */
1382                 nfs_fill_super(s, &data);
1383         }
1384
1385         mntroot = nfs_get_root(s, &mntfh);
1386         if (IS_ERR(mntroot)) {
1387                 error = PTR_ERR(mntroot);
1388                 goto error_splat_super;
1389         }
1390
1391         s->s_flags |= MS_ACTIVE;
1392         mnt->mnt_sb = s;
1393         mnt->mnt_root = mntroot;
1394         error = 0;
1395
1396 out:
1397         kfree(data.nfs_server.hostname);
1398         return error;
1399
1400 out_err_nosb:
1401         nfs_free_server(server);
1402         goto out;
1403
1404 error_splat_super:
1405         up_write(&s->s_umount);
1406         deactivate_super(s);
1407         goto out;
1408 }
1409
1410 /*
1411  * Destroy an NFS2/3 superblock
1412  */
1413 static void nfs_kill_super(struct super_block *s)
1414 {
1415         struct nfs_server *server = NFS_SB(s);
1416
1417         kill_anon_super(s);
1418         nfs_free_server(server);
1419 }
1420
1421 /*
1422  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
1423  */
1424 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
1425                            const char *dev_name, void *raw_data,
1426                            struct vfsmount *mnt)
1427 {
1428         struct nfs_clone_mount *data = raw_data;
1429         struct super_block *s;
1430         struct nfs_server *server;
1431         struct dentry *mntroot;
1432         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1433         struct nfs_sb_mountdata sb_mntdata = {
1434                 .mntflags = flags,
1435         };
1436         int error;
1437
1438         dprintk("--> nfs_xdev_get_sb()\n");
1439
1440         /* create a new volume representation */
1441         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1442         if (IS_ERR(server)) {
1443                 error = PTR_ERR(server);
1444                 goto out_err_noserver;
1445         }
1446         sb_mntdata.server = server;
1447
1448         if (server->flags & NFS_MOUNT_UNSHARED)
1449                 compare_super = NULL;
1450
1451         /* Get a superblock - note that we may end up sharing one that already exists */
1452         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1453         if (IS_ERR(s)) {
1454                 error = PTR_ERR(s);
1455                 goto out_err_nosb;
1456         }
1457
1458         if (s->s_fs_info != server) {
1459                 nfs_free_server(server);
1460                 server = NULL;
1461         }
1462
1463         if (!s->s_root) {
1464                 /* initial superblock/root creation */
1465                 nfs_clone_super(s, data->sb);
1466         }
1467
1468         mntroot = nfs_get_root(s, data->fh);
1469         if (IS_ERR(mntroot)) {
1470                 error = PTR_ERR(mntroot);
1471                 goto error_splat_super;
1472         }
1473
1474         s->s_flags |= MS_ACTIVE;
1475         mnt->mnt_sb = s;
1476         mnt->mnt_root = mntroot;
1477
1478         dprintk("<-- nfs_xdev_get_sb() = 0\n");
1479         return 0;
1480
1481 out_err_nosb:
1482         nfs_free_server(server);
1483 out_err_noserver:
1484         dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
1485         return error;
1486
1487 error_splat_super:
1488         up_write(&s->s_umount);
1489         deactivate_super(s);
1490         dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
1491         return error;
1492 }
1493
1494 #ifdef CONFIG_NFS_V4
1495
1496 /*
1497  * Finish setting up a cloned NFS4 superblock
1498  */
1499 static void nfs4_clone_super(struct super_block *sb,
1500                             const struct super_block *old_sb)
1501 {
1502         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1503         sb->s_blocksize = old_sb->s_blocksize;
1504         sb->s_maxbytes = old_sb->s_maxbytes;
1505         sb->s_time_gran = 1;
1506         sb->s_op = old_sb->s_op;
1507         nfs_initialise_sb(sb);
1508 }
1509
1510 /*
1511  * Set up an NFS4 superblock
1512  */
1513 static void nfs4_fill_super(struct super_block *sb)
1514 {
1515         sb->s_time_gran = 1;
1516         sb->s_op = &nfs4_sops;
1517         nfs_initialise_sb(sb);
1518 }
1519
1520 /*
1521  * Validate NFSv4 mount options
1522  */
1523 static int nfs4_validate_mount_data(void *options,
1524                                     struct nfs_parsed_mount_data *args,
1525                                     const char *dev_name)
1526 {
1527         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
1528         char *c;
1529
1530         if (data == NULL)
1531                 goto out_no_data;
1532
1533         memset(args, 0, sizeof(*args));
1534         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1535         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1536         args->timeo             = 600;
1537         args->retrans           = 2;
1538         args->acregmin          = 3;
1539         args->acregmax          = 60;
1540         args->acdirmin          = 30;
1541         args->acdirmax          = 60;
1542         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1543
1544         switch (data->version) {
1545         case 1:
1546                 if (data->host_addrlen != sizeof(args->nfs_server.address))
1547                         goto out_no_address;
1548                 if (copy_from_user(&args->nfs_server.address,
1549                                    data->host_addr,
1550                                    sizeof(args->nfs_server.address)))
1551                         return -EFAULT;
1552                 if (args->nfs_server.address.sin_port == 0)
1553                         args->nfs_server.address.sin_port = htons(NFS_PORT);
1554                 if (!nfs_verify_server_address((struct sockaddr *)
1555                                                 &args->nfs_server.address))
1556                         goto out_no_address;
1557
1558                 switch (data->auth_flavourlen) {
1559                 case 0:
1560                         args->auth_flavors[0] = RPC_AUTH_UNIX;
1561                         break;
1562                 case 1:
1563                         if (copy_from_user(&args->auth_flavors[0],
1564                                            data->auth_flavours,
1565                                            sizeof(args->auth_flavors[0])))
1566                                 return -EFAULT;
1567                         break;
1568                 default:
1569                         goto out_inval_auth;
1570                 }
1571
1572                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
1573                 if (IS_ERR(c))
1574                         return PTR_ERR(c);
1575                 args->nfs_server.hostname = c;
1576
1577                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
1578                 if (IS_ERR(c))
1579                         return PTR_ERR(c);
1580                 args->nfs_server.export_path = c;
1581                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
1582
1583                 c = strndup_user(data->client_addr.data, 16);
1584                 if (IS_ERR(c))
1585                         return PTR_ERR(c);
1586                 args->client_address = c;
1587
1588                 /*
1589                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
1590                  * can deal with.
1591                  */
1592
1593                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
1594                 args->rsize     = data->rsize;
1595                 args->wsize     = data->wsize;
1596                 args->timeo     = data->timeo;
1597                 args->retrans   = data->retrans;
1598                 args->acregmin  = data->acregmin;
1599                 args->acregmax  = data->acregmax;
1600                 args->acdirmin  = data->acdirmin;
1601                 args->acdirmax  = data->acdirmax;
1602                 args->nfs_server.protocol = data->proto;
1603
1604                 break;
1605         default: {
1606                 unsigned int len;
1607
1608                 if (nfs_parse_mount_options((char *)options, args) == 0)
1609                         return -EINVAL;
1610
1611                 if (!nfs_verify_server_address((struct sockaddr *)
1612                                                 &args->nfs_server.address))
1613                         return -EINVAL;
1614
1615                 switch (args->auth_flavor_len) {
1616                 case 0:
1617                         args->auth_flavors[0] = RPC_AUTH_UNIX;
1618                         break;
1619                 case 1:
1620                         break;
1621                 default:
1622                         goto out_inval_auth;
1623                 }
1624
1625                 /*
1626                  * Split "dev_name" into "hostname:mntpath".
1627                  */
1628                 c = strchr(dev_name, ':');
1629                 if (c == NULL)
1630                         return -EINVAL;
1631                 /* while calculating len, pretend ':' is '\0' */
1632                 len = c - dev_name;
1633                 if (len > NFS4_MAXNAMLEN)
1634                         return -ENAMETOOLONG;
1635                 args->nfs_server.hostname = kzalloc(len, GFP_KERNEL);
1636                 if (args->nfs_server.hostname == NULL)
1637                         return -ENOMEM;
1638                 strncpy(args->nfs_server.hostname, dev_name, len - 1);
1639
1640                 c++;                    /* step over the ':' */
1641                 len = strlen(c);
1642                 if (len > NFS4_MAXPATHLEN)
1643                         return -ENAMETOOLONG;
1644                 args->nfs_server.export_path = kzalloc(len + 1, GFP_KERNEL);
1645                 if (args->nfs_server.export_path == NULL)
1646                         return -ENOMEM;
1647                 strncpy(args->nfs_server.export_path, c, len);
1648
1649                 dprintk("MNTPATH: %s\n", args->nfs_server.export_path);
1650
1651                 if (args->client_address == NULL)
1652                         goto out_no_client_address;
1653
1654                 break;
1655                 }
1656         }
1657
1658         return 0;
1659
1660 out_no_data:
1661         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
1662         return -EINVAL;
1663
1664 out_inval_auth:
1665         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
1666                  data->auth_flavourlen);
1667         return -EINVAL;
1668
1669 out_no_address:
1670         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
1671         return -EINVAL;
1672
1673 out_no_client_address:
1674         dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
1675         return -EINVAL;
1676 }
1677
1678 /*
1679  * Get the superblock for an NFS4 mountpoint
1680  */
1681 static int nfs4_get_sb(struct file_system_type *fs_type,
1682         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1683 {
1684         struct nfs_parsed_mount_data data;
1685         struct super_block *s;
1686         struct nfs_server *server;
1687         struct nfs_fh mntfh;
1688         struct dentry *mntroot;
1689         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1690         struct nfs_sb_mountdata sb_mntdata = {
1691                 .mntflags = flags,
1692         };
1693         int error;
1694
1695         /* Validate the mount data */
1696         error = nfs4_validate_mount_data(raw_data, &data, dev_name);
1697         if (error < 0)
1698                 goto out;
1699
1700         /* Get a volume representation */
1701         server = nfs4_create_server(&data, &mntfh);
1702         if (IS_ERR(server)) {
1703                 error = PTR_ERR(server);
1704                 goto out;
1705         }
1706         sb_mntdata.server = server;
1707
1708         if (server->flags & NFS4_MOUNT_UNSHARED)
1709                 compare_super = NULL;
1710
1711         /* Get a superblock - note that we may end up sharing one that already exists */
1712         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1713         if (IS_ERR(s)) {
1714                 error = PTR_ERR(s);
1715                 goto out_free;
1716         }
1717
1718         if (s->s_fs_info != server) {
1719                 nfs_free_server(server);
1720                 server = NULL;
1721         }
1722
1723         if (!s->s_root) {
1724                 /* initial superblock/root creation */
1725                 nfs4_fill_super(s);
1726         }
1727
1728         mntroot = nfs4_get_root(s, &mntfh);
1729         if (IS_ERR(mntroot)) {
1730                 error = PTR_ERR(mntroot);
1731                 goto error_splat_super;
1732         }
1733
1734         s->s_flags |= MS_ACTIVE;
1735         mnt->mnt_sb = s;
1736         mnt->mnt_root = mntroot;
1737         error = 0;
1738
1739 out:
1740         kfree(data.client_address);
1741         kfree(data.nfs_server.export_path);
1742         kfree(data.nfs_server.hostname);
1743         return error;
1744
1745 out_free:
1746         nfs_free_server(server);
1747         goto out;
1748
1749 error_splat_super:
1750         up_write(&s->s_umount);
1751         deactivate_super(s);
1752         goto out;
1753 }
1754
1755 static void nfs4_kill_super(struct super_block *sb)
1756 {
1757         struct nfs_server *server = NFS_SB(sb);
1758
1759         nfs_return_all_delegations(sb);
1760         kill_anon_super(sb);
1761
1762         nfs4_renewd_prepare_shutdown(server);
1763         nfs_free_server(server);
1764 }
1765
1766 /*
1767  * Clone an NFS4 server record on xdev traversal (FSID-change)
1768  */
1769 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
1770                             const char *dev_name, void *raw_data,
1771                             struct vfsmount *mnt)
1772 {
1773         struct nfs_clone_mount *data = raw_data;
1774         struct super_block *s;
1775         struct nfs_server *server;
1776         struct dentry *mntroot;
1777         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1778         struct nfs_sb_mountdata sb_mntdata = {
1779                 .mntflags = flags,
1780         };
1781         int error;
1782
1783         dprintk("--> nfs4_xdev_get_sb()\n");
1784
1785         /* create a new volume representation */
1786         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1787         if (IS_ERR(server)) {
1788                 error = PTR_ERR(server);
1789                 goto out_err_noserver;
1790         }
1791         sb_mntdata.server = server;
1792
1793         if (server->flags & NFS4_MOUNT_UNSHARED)
1794                 compare_super = NULL;
1795
1796         /* Get a superblock - note that we may end up sharing one that already exists */
1797         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1798         if (IS_ERR(s)) {
1799                 error = PTR_ERR(s);
1800                 goto out_err_nosb;
1801         }
1802
1803         if (s->s_fs_info != server) {
1804                 nfs_free_server(server);
1805                 server = NULL;
1806         }
1807
1808         if (!s->s_root) {
1809                 /* initial superblock/root creation */
1810                 nfs4_clone_super(s, data->sb);
1811         }
1812
1813         mntroot = nfs4_get_root(s, data->fh);
1814         if (IS_ERR(mntroot)) {
1815                 error = PTR_ERR(mntroot);
1816                 goto error_splat_super;
1817         }
1818
1819         s->s_flags |= MS_ACTIVE;
1820         mnt->mnt_sb = s;
1821         mnt->mnt_root = mntroot;
1822
1823         dprintk("<-- nfs4_xdev_get_sb() = 0\n");
1824         return 0;
1825
1826 out_err_nosb:
1827         nfs_free_server(server);
1828 out_err_noserver:
1829         dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
1830         return error;
1831
1832 error_splat_super:
1833         up_write(&s->s_umount);
1834         deactivate_super(s);
1835         dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
1836         return error;
1837 }
1838
1839 /*
1840  * Create an NFS4 server record on referral traversal
1841  */
1842 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
1843                                 const char *dev_name, void *raw_data,
1844                                 struct vfsmount *mnt)
1845 {
1846         struct nfs_clone_mount *data = raw_data;
1847         struct super_block *s;
1848         struct nfs_server *server;
1849         struct dentry *mntroot;
1850         struct nfs_fh mntfh;
1851         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1852         struct nfs_sb_mountdata sb_mntdata = {
1853                 .mntflags = flags,
1854         };
1855         int error;
1856
1857         dprintk("--> nfs4_referral_get_sb()\n");
1858
1859         /* create a new volume representation */
1860         server = nfs4_create_referral_server(data, &mntfh);
1861         if (IS_ERR(server)) {
1862                 error = PTR_ERR(server);
1863                 goto out_err_noserver;
1864         }
1865         sb_mntdata.server = server;
1866
1867         if (server->flags & NFS4_MOUNT_UNSHARED)
1868                 compare_super = NULL;
1869
1870         /* Get a superblock - note that we may end up sharing one that already exists */
1871         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1872         if (IS_ERR(s)) {
1873                 error = PTR_ERR(s);
1874                 goto out_err_nosb;
1875         }
1876
1877         if (s->s_fs_info != server) {
1878                 nfs_free_server(server);
1879                 server = NULL;
1880         }
1881
1882         if (!s->s_root) {
1883                 /* initial superblock/root creation */
1884                 nfs4_fill_super(s);
1885         }
1886
1887         mntroot = nfs4_get_root(s, &mntfh);
1888         if (IS_ERR(mntroot)) {
1889                 error = PTR_ERR(mntroot);
1890                 goto error_splat_super;
1891         }
1892
1893         s->s_flags |= MS_ACTIVE;
1894         mnt->mnt_sb = s;
1895         mnt->mnt_root = mntroot;
1896
1897         dprintk("<-- nfs4_referral_get_sb() = 0\n");
1898         return 0;
1899
1900 out_err_nosb:
1901         nfs_free_server(server);
1902 out_err_noserver:
1903         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
1904         return error;
1905
1906 error_splat_super:
1907         up_write(&s->s_umount);
1908         deactivate_super(s);
1909         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
1910         return error;
1911 }
1912
1913 #endif /* CONFIG_NFS_V4 */