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/nfs_fs.h>
  37 #include <linux/nfs_mount.h>
  38 #include <linux/nfs4_mount.h>
  39 #include <linux/lockd/bind.h>
  40 #include <linux/smp_lock.h>
  41 #include <linux/seq_file.h>
  42 #include <linux/mount.h>
  43 #include <linux/nfs_idmap.h>
  44 #include <linux/vfs.h>
  45 #include <linux/inet.h>
  46 #include <linux/nfs_xdr.h>
  47 #include <linux/magic.h>
  48 #include <linux/parser.h>
  49
  50 #include <asm/system.h>
  51 #include <asm/uaccess.h>
  52
  53 #include "nfs4_fs.h"
  54 #include "callback.h"
  55 #include "delegation.h"
  56 #include "iostat.h"
  57 #include "internal.h"
  58
  59 #define NFSDBG_FACILITY         NFSDBG_VFS
  60
  61
  62 struct nfs_parsed_mount_data {
  63         int                     flags;
  64         int                     rsize, wsize;
  65         int                     timeo, retrans;
  66         int                     acregmin, acregmax,
  67                                 acdirmin, acdirmax;
  68         int                     namlen;
  69         unsigned int            bsize;
  70         unsigned int            auth_flavor_len;
  71         rpc_authflavor_t        auth_flavors[1];
  72         char                    *client_address;
  73
  74         struct {
  75                 struct sockaddr_in      address;
  76                 char                    *hostname;
  77                 unsigned int            program;
  78                 unsigned int            version;
  79                 unsigned short          port;
  80                 int                     protocol;
  81         } mount_server;
  82
  83         struct {
  84                 struct sockaddr_in      address;
  85                 char                    *hostname;
  86                 char                    *export_path;
  87                 unsigned int            program;
  88                 int                     protocol;
  89         } nfs_server;
  90 };
  91
  92 enum {
  93         /* Mount options that take no arguments */
  94         Opt_soft, Opt_hard,
  95         Opt_intr, Opt_nointr,
  96         Opt_posix, Opt_noposix,
  97         Opt_cto, Opt_nocto,
  98         Opt_ac, Opt_noac,
  99         Opt_lock, Opt_nolock,
 100         Opt_v2, Opt_v3,
 101         Opt_udp, Opt_tcp,
 102         Opt_acl, Opt_noacl,
 103         Opt_rdirplus, Opt_nordirplus,
 104         Opt_sharecache, Opt_nosharecache,
 105
 106         /* Mount options that take integer arguments */
 107         Opt_port,
 108         Opt_rsize, Opt_wsize, Opt_bsize,
 109         Opt_timeo, Opt_retrans,
 110         Opt_acregmin, Opt_acregmax,
 111         Opt_acdirmin, Opt_acdirmax,
 112         Opt_actimeo,
 113         Opt_namelen,
 114         Opt_mountport,
 115         Opt_mountprog, Opt_mountvers,
 116         Opt_nfsprog, Opt_nfsvers,
 117
 118         /* Mount options that take string arguments */
 119         Opt_sec, Opt_proto, Opt_mountproto,
 120         Opt_addr, Opt_mountaddr, Opt_clientaddr,
 121
 122         /* Mount options that are ignored */
 123         Opt_userspace, Opt_deprecated,
 124
 125         Opt_err
 126 };
 127
 128 static match_table_t nfs_mount_option_tokens = {
 129         { Opt_userspace, "bg" },
 130         { Opt_userspace, "fg" },
 131         { Opt_soft, "soft" },
 132         { Opt_hard, "hard" },
 133         { Opt_intr, "intr" },
 134         { Opt_nointr, "nointr" },
 135         { Opt_posix, "posix" },
 136         { Opt_noposix, "noposix" },
 137         { Opt_cto, "cto" },
 138         { Opt_nocto, "nocto" },
 139         { Opt_ac, "ac" },
 140         { Opt_noac, "noac" },
 141         { Opt_lock, "lock" },
 142         { Opt_nolock, "nolock" },
 143         { Opt_v2, "v2" },
 144         { Opt_v3, "v3" },
 145         { Opt_udp, "udp" },
 146         { Opt_tcp, "tcp" },
 147         { Opt_acl, "acl" },
 148         { Opt_noacl, "noacl" },
 149         { Opt_rdirplus, "rdirplus" },
 150         { Opt_nordirplus, "nordirplus" },
 151         { Opt_sharecache, "sharecache" },
 152         { Opt_nosharecache, "nosharecache" },
 153
 154         { Opt_port, "port=%u" },
 155         { Opt_rsize, "rsize=%u" },
 156         { Opt_wsize, "wsize=%u" },
 157         { Opt_bsize, "bsize=%u" },
 158         { Opt_timeo, "timeo=%u" },
 159         { Opt_retrans, "retrans=%u" },
 160         { Opt_acregmin, "acregmin=%u" },
 161         { Opt_acregmax, "acregmax=%u" },
 162         { Opt_acdirmin, "acdirmin=%u" },
 163         { Opt_acdirmax, "acdirmax=%u" },
 164         { Opt_actimeo, "actimeo=%u" },
 165         { Opt_userspace, "retry=%u" },
 166         { Opt_namelen, "namlen=%u" },
 167         { Opt_mountport, "mountport=%u" },
 168         { Opt_mountprog, "mountprog=%u" },
 169         { Opt_mountvers, "mountvers=%u" },
 170         { Opt_nfsprog, "nfsprog=%u" },
 171         { Opt_nfsvers, "nfsvers=%u" },
 172         { Opt_nfsvers, "vers=%u" },
 173
 174         { Opt_sec, "sec=%s" },
 175         { Opt_proto, "proto=%s" },
 176         { Opt_mountproto, "mountproto=%s" },
 177         { Opt_addr, "addr=%s" },
 178         { Opt_clientaddr, "clientaddr=%s" },
 179         { Opt_userspace, "mounthost=%s" },
 180         { Opt_mountaddr, "mountaddr=%s" },
 181
 182         { Opt_err, NULL }
 183 };
 184
 185 enum {
 186         Opt_xprt_udp, Opt_xprt_tcp,
 187
 188         Opt_xprt_err
 189 };
 190
 191 static match_table_t nfs_xprt_protocol_tokens = {
 192         { Opt_xprt_udp, "udp" },
 193         { Opt_xprt_tcp, "tcp" },
 194
 195         { Opt_xprt_err, NULL }
 196 };
 197
 198 enum {
 199         Opt_sec_none, Opt_sec_sys,
 200         Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
 201         Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
 202         Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
 203
 204         Opt_sec_err
 205 };
 206
 207 static match_table_t nfs_secflavor_tokens = {
 208         { Opt_sec_none, "none" },
 209         { Opt_sec_none, "null" },
 210         { Opt_sec_sys, "sys" },
 211
 212         { Opt_sec_krb5, "krb5" },
 213         { Opt_sec_krb5i, "krb5i" },
 214         { Opt_sec_krb5p, "krb5p" },
 215
 216         { Opt_sec_lkey, "lkey" },
 217         { Opt_sec_lkeyi, "lkeyi" },
 218         { Opt_sec_lkeyp, "lkeyp" },
 219
 220         { Opt_sec_err, NULL }
 221 };
 222
 223
 224 static void nfs_umount_begin(struct vfsmount *, int);
 225 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 226 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 227 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
 228 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
 229 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
 230                 int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 231 static void nfs_kill_super(struct super_block *);
 232
 233 static struct file_system_type nfs_fs_type = {
 234         .owner          = THIS_MODULE,
 235         .name           = "nfs",
 236         .get_sb         = nfs_get_sb,
 237         .kill_sb        = nfs_kill_super,
 238         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 239 };
 240
 241 struct file_system_type nfs_xdev_fs_type = {
 242         .owner          = THIS_MODULE,
 243         .name           = "nfs",
 244         .get_sb         = nfs_xdev_get_sb,
 245         .kill_sb        = nfs_kill_super,
 246         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 247 };
 248
 249 static const struct super_operations nfs_sops = {
 250         .alloc_inode    = nfs_alloc_inode,
 251         .destroy_inode  = nfs_destroy_inode,
 252         .write_inode    = nfs_write_inode,
 253         .statfs         = nfs_statfs,
 254         .clear_inode    = nfs_clear_inode,
 255         .umount_begin   = nfs_umount_begin,
 256         .show_options   = nfs_show_options,
 257         .show_stats     = nfs_show_stats,
 258 };
 259
 260 #ifdef CONFIG_NFS_V4
 261 static int nfs4_get_sb(struct file_system_type *fs_type,
 262         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 263 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
 264         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 265 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 266         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 267 static void nfs4_kill_super(struct super_block *sb);
 268
 269 static struct file_system_type nfs4_fs_type = {
 270         .owner          = THIS_MODULE,
 271         .name           = "nfs4",
 272         .get_sb         = nfs4_get_sb,
 273         .kill_sb        = nfs4_kill_super,
 274         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 275 };
 276
 277 struct file_system_type nfs4_xdev_fs_type = {
 278         .owner          = THIS_MODULE,
 279         .name           = "nfs4",
 280         .get_sb         = nfs4_xdev_get_sb,
 281         .kill_sb        = nfs4_kill_super,
 282         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 283 };
 284
 285 struct file_system_type nfs4_referral_fs_type = {
 286         .owner          = THIS_MODULE,
 287         .name           = "nfs4",
 288         .get_sb         = nfs4_referral_get_sb,
 289         .kill_sb        = nfs4_kill_super,
 290         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 291 };
 292
 293 static const struct super_operations nfs4_sops = {
 294         .alloc_inode    = nfs_alloc_inode,
 295         .destroy_inode  = nfs_destroy_inode,
 296         .write_inode    = nfs_write_inode,
 297         .statfs         = nfs_statfs,
 298         .clear_inode    = nfs4_clear_inode,
 299         .umount_begin   = nfs_umount_begin,
 300         .show_options   = nfs_show_options,
 301         .show_stats     = nfs_show_stats,
 302 };
 303 #endif
 304
 305 static struct shrinker acl_shrinker = {
 306         .shrink         = nfs_access_cache_shrinker,
 307         .seeks          = DEFAULT_SEEKS,
 308 };
 309
 310 /*
 311  * Register the NFS filesystems
 312  */
 313 int __init register_nfs_fs(void)
 314 {
 315         int ret;
 316
 317         ret = register_filesystem(&nfs_fs_type);
 318         if (ret < 0)
 319                 goto error_0;
 320
 321         ret = nfs_register_sysctl();
 322         if (ret < 0)
 323                 goto error_1;
 324 #ifdef CONFIG_NFS_V4
 325         ret = register_filesystem(&nfs4_fs_type);
 326         if (ret < 0)
 327                 goto error_2;
 328 #endif
 329         register_shrinker(&acl_shrinker);
 330         return 0;
 331
 332 #ifdef CONFIG_NFS_V4
 333 error_2:
 334         nfs_unregister_sysctl();
 335 #endif
 336 error_1:
 337         unregister_filesystem(&nfs_fs_type);
 338 error_0:
 339         return ret;
 340 }
 341
 342 /*
 343  * Unregister the NFS filesystems
 344  */
 345 void __exit unregister_nfs_fs(void)
 346 {
 347         unregister_shrinker(&acl_shrinker);
 348 #ifdef CONFIG_NFS_V4
 349         unregister_filesystem(&nfs4_fs_type);
 350 #endif
 351         nfs_unregister_sysctl();
 352         unregister_filesystem(&nfs_fs_type);
 353 }
 354
 355 /*
 356  * Deliver file system statistics to userspace
 357  */
 358 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 359 {
 360         struct nfs_server *server = NFS_SB(dentry->d_sb);
 361         unsigned char blockbits;
 362         unsigned long blockres;
 363         struct nfs_fh *fh = NFS_FH(dentry->d_inode);
 364         struct nfs_fattr fattr;
 365         struct nfs_fsstat res = {
 366                         .fattr = &fattr,
 367         };
 368         int error;
 369
 370         lock_kernel();
 371
 372         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 373         if (error < 0)
 374                 goto out_err;
 375         buf->f_type = NFS_SUPER_MAGIC;
 376
 377         /*
 378          * Current versions of glibc do not correctly handle the
 379          * case where f_frsize != f_bsize.  Eventually we want to
 380          * report the value of wtmult in this field.
 381          */
 382         buf->f_frsize = dentry->d_sb->s_blocksize;
 383
 384         /*
 385          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 386          * are reported in units of f_frsize.  Linux hasn't had
 387          * an f_frsize field in its statfs struct until recently,
 388          * thus historically Linux's sys_statfs reports these
 389          * fields in units of f_bsize.
 390          */
 391         buf->f_bsize = dentry->d_sb->s_blocksize;
 392         blockbits = dentry->d_sb->s_blocksize_bits;
 393         blockres = (1 << blockbits) - 1;
 394         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 395         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 396         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 397
 398         buf->f_files = res.tfiles;
 399         buf->f_ffree = res.afiles;
 400
 401         buf->f_namelen = server->namelen;
 402
 403         unlock_kernel();
 404         return 0;
 405
 406  out_err:
 407         dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
 408         unlock_kernel();
 409         return error;
 410 }
 411
 412 /*
 413  * Map the security flavour number to a name
 414  */
 415 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 416 {
 417         static const struct {
 418                 rpc_authflavor_t flavour;
 419                 const char *str;
 420         } sec_flavours[] = {
 421                 { RPC_AUTH_NULL, "null" },
 422                 { RPC_AUTH_UNIX, "sys" },
 423                 { RPC_AUTH_GSS_KRB5, "krb5" },
 424                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 425                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 426                 { RPC_AUTH_GSS_LKEY, "lkey" },
 427                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 428                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 429                 { RPC_AUTH_GSS_SPKM, "spkm" },
 430                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 431                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 432                 { UINT_MAX, "unknown" }
 433         };
 434         int i;
 435
 436         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 437                 if (sec_flavours[i].flavour == flavour)
 438                         break;
 439         }
 440         return sec_flavours[i].str;
 441 }
 442
 443 /*
 444  * Describe the mount options in force on this server representation
 445  */
 446 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
 447 {
 448         static const struct proc_nfs_info {
 449                 int flag;
 450                 const char *str;
 451                 const char *nostr;
 452         } nfs_info[] = {
 453                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 454                 { NFS_MOUNT_INTR, ",intr", "" },
 455                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 456                 { NFS_MOUNT_NOAC, ",noac", "" },
 457                 { NFS_MOUNT_NONLM, ",nolock", "" },
 458                 { NFS_MOUNT_NOACL, ",noacl", "" },
 459                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 460                 { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
 461                 { 0, NULL, NULL }
 462         };
 463         const struct proc_nfs_info *nfs_infop;
 464         struct nfs_client *clp = nfss->nfs_client;
 465         char buf[12];
 466         const char *proto;
 467
 468         seq_printf(m, ",vers=%d", clp->rpc_ops->version);
 469         seq_printf(m, ",rsize=%d", nfss->rsize);
 470         seq_printf(m, ",wsize=%d", nfss->wsize);
 471         if (nfss->acregmin != 3*HZ || showdefaults)
 472                 seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
 473         if (nfss->acregmax != 60*HZ || showdefaults)
 474                 seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
 475         if (nfss->acdirmin != 30*HZ || showdefaults)
 476                 seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
 477         if (nfss->acdirmax != 60*HZ || showdefaults)
 478                 seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
 479         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 480                 if (nfss->flags & nfs_infop->flag)
 481                         seq_puts(m, nfs_infop->str);
 482                 else
 483                         seq_puts(m, nfs_infop->nostr);
 484         }
 485         switch (nfss->client->cl_xprt->prot) {
 486                 case IPPROTO_TCP:
 487                         proto = "tcp";
 488                         break;
 489                 case IPPROTO_UDP:
 490                         proto = "udp";
 491                         break;
 492                 default:
 493                         snprintf(buf, sizeof(buf), "%u", nfss->client->cl_xprt->prot);
 494                         proto = buf;
 495         }
 496         seq_printf(m, ",proto=%s", proto);
 497         seq_printf(m, ",timeo=%lu", 10U * clp->retrans_timeo / HZ);
 498         seq_printf(m, ",retrans=%u", clp->retrans_count);
 499         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 500 }
 501
 502 /*
 503  * Describe the mount options on this VFS mountpoint
 504  */
 505 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 506 {
 507         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 508
 509         nfs_show_mount_options(m, nfss, 0);
 510
 511         seq_printf(m, ",addr="NIPQUAD_FMT,
 512                 NIPQUAD(nfss->nfs_client->cl_addr.sin_addr));
 513
 514         return 0;
 515 }
 516
 517 /*
 518  * Present statistical information for this VFS mountpoint
 519  */
 520 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 521 {
 522         int i, cpu;
 523         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 524         struct rpc_auth *auth = nfss->client->cl_auth;
 525         struct nfs_iostats totals = { };
 526
 527         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 528
 529         /*
 530          * Display all mount option settings
 531          */
 532         seq_printf(m, "\n\topts:\t");
 533         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 534         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 535         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 536         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 537         nfs_show_mount_options(m, nfss, 1);
 538
 539         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 540
 541         seq_printf(m, "\n\tcaps:\t");
 542         seq_printf(m, "caps=0x%x", nfss->caps);
 543         seq_printf(m, ",wtmult=%d", nfss->wtmult);
 544         seq_printf(m, ",dtsize=%d", nfss->dtsize);
 545         seq_printf(m, ",bsize=%d", nfss->bsize);
 546         seq_printf(m, ",namelen=%d", nfss->namelen);
 547
 548 #ifdef CONFIG_NFS_V4
 549         if (nfss->nfs_client->cl_nfsversion == 4) {
 550                 seq_printf(m, "\n\tnfsv4:\t");
 551                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 552                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 553                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 554         }
 555 #endif
 556
 557         /*
 558          * Display security flavor in effect for this mount
 559          */
 560         seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
 561         if (auth->au_flavor)
 562                 seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
 563
 564         /*
 565          * Display superblock I/O counters
 566          */
 567         for_each_possible_cpu(cpu) {
 568                 struct nfs_iostats *stats;
 569
 570                 preempt_disable();
 571                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 572
 573                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 574                         totals.events[i] += stats->events[i];
 575                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 576                         totals.bytes[i] += stats->bytes[i];
 577
 578                 preempt_enable();
 579         }
 580
 581         seq_printf(m, "\n\tevents:\t");
 582         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 583                 seq_printf(m, "%lu ", totals.events[i]);
 584         seq_printf(m, "\n\tbytes:\t");
 585         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 586                 seq_printf(m, "%Lu ", totals.bytes[i]);
 587         seq_printf(m, "\n");
 588
 589         rpc_print_iostats(m, nfss->client);
 590
 591         return 0;
 592 }
 593
 594 /*
 595  * Begin unmount by attempting to remove all automounted mountpoints we added
 596  * in response to xdev traversals and referrals
 597  */
 598 static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
 599 {
 600         struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
 601         struct rpc_clnt *rpc;
 602
 603         shrink_submounts(vfsmnt, &nfs_automount_list);
 604
 605         if (!(flags & MNT_FORCE))
 606                 return;
 607         /* -EIO all pending I/O */
 608         rpc = server->client_acl;
 609         if (!IS_ERR(rpc))
 610                 rpc_killall_tasks(rpc);
 611         rpc = server->client;
 612         if (!IS_ERR(rpc))
 613                 rpc_killall_tasks(rpc);
 614 }
 615
 616 /*
 617  * Sanity-check a server address provided by the mount command
 618  */
 619 static int nfs_verify_server_address(struct sockaddr *addr)
 620 {
 621         switch (addr->sa_family) {
 622         case AF_INET: {
 623                 struct sockaddr_in *sa = (struct sockaddr_in *) addr;
 624                 if (sa->sin_addr.s_addr != INADDR_ANY)
 625                         return 1;
 626                 break;
 627         }
 628         }
 629
 630         return 0;
 631 }
 632
 633 /*
 634  * Error-check and convert a string of mount options from user space into
 635  * a data structure
 636  */
 637 static int nfs_parse_mount_options(char *raw,
 638                                    struct nfs_parsed_mount_data *mnt)
 639 {
 640         char *p, *string;
 641
 642         if (!raw) {
 643                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 644                 return 1;
 645         }
 646         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 647
 648         while ((p = strsep(&raw, ",")) != NULL) {
 649                 substring_t args[MAX_OPT_ARGS];
 650                 int option, token;
 651
 652                 if (!*p)
 653                         continue;
 654
 655                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
 656
 657                 token = match_token(p, nfs_mount_option_tokens, args);
 658                 switch (token) {
 659                 case Opt_soft:
 660                         mnt->flags |= NFS_MOUNT_SOFT;
 661                         break;
 662                 case Opt_hard:
 663                         mnt->flags &= ~NFS_MOUNT_SOFT;
 664                         break;
 665                 case Opt_intr:
 666                         mnt->flags |= NFS_MOUNT_INTR;
 667                         break;
 668                 case Opt_nointr:
 669                         mnt->flags &= ~NFS_MOUNT_INTR;
 670                         break;
 671                 case Opt_posix:
 672                         mnt->flags |= NFS_MOUNT_POSIX;
 673                         break;
 674                 case Opt_noposix:
 675                         mnt->flags &= ~NFS_MOUNT_POSIX;
 676                         break;
 677                 case Opt_cto:
 678                         mnt->flags &= ~NFS_MOUNT_NOCTO;
 679                         break;
 680                 case Opt_nocto:
 681                         mnt->flags |= NFS_MOUNT_NOCTO;
 682                         break;
 683                 case Opt_ac:
 684                         mnt->flags &= ~NFS_MOUNT_NOAC;
 685                         break;
 686                 case Opt_noac:
 687                         mnt->flags |= NFS_MOUNT_NOAC;
 688                         break;
 689                 case Opt_lock:
 690                         mnt->flags &= ~NFS_MOUNT_NONLM;
 691                         break;
 692                 case Opt_nolock:
 693                         mnt->flags |= NFS_MOUNT_NONLM;
 694                         break;
 695                 case Opt_v2:
 696                         mnt->flags &= ~NFS_MOUNT_VER3;
 697                         break;
 698                 case Opt_v3:
 699                         mnt->flags |= NFS_MOUNT_VER3;
 700                         break;
 701                 case Opt_udp:
 702                         mnt->flags &= ~NFS_MOUNT_TCP;
 703                         mnt->nfs_server.protocol = IPPROTO_UDP;
 704                         mnt->timeo = 7;
 705                         mnt->retrans = 5;
 706                         break;
 707                 case Opt_tcp:
 708                         mnt->flags |= NFS_MOUNT_TCP;
 709                         mnt->nfs_server.protocol = IPPROTO_TCP;
 710                         mnt->timeo = 600;
 711                         mnt->retrans = 2;
 712                         break;
 713                 case Opt_acl:
 714                         mnt->flags &= ~NFS_MOUNT_NOACL;
 715                         break;
 716                 case Opt_noacl:
 717                         mnt->flags |= NFS_MOUNT_NOACL;
 718                         break;
 719                 case Opt_rdirplus:
 720                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
 721                         break;
 722                 case Opt_nordirplus:
 723                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
 724                         break;
 725                 case Opt_sharecache:
 726                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
 727                         break;
 728                 case Opt_nosharecache:
 729                         mnt->flags |= NFS_MOUNT_UNSHARED;
 730                         break;
 731
 732                 case Opt_port:
 733                         if (match_int(args, &option))
 734                                 return 0;
 735                         if (option < 0 || option > 65535)
 736                                 return 0;
 737                         mnt->nfs_server.address.sin_port = htons(option);
 738                         break;
 739                 case Opt_rsize:
 740                         if (match_int(args, &mnt->rsize))
 741                                 return 0;
 742                         break;
 743                 case Opt_wsize:
 744                         if (match_int(args, &mnt->wsize))
 745                                 return 0;
 746                         break;
 747                 case Opt_bsize:
 748                         if (match_int(args, &option))
 749                                 return 0;
 750                         if (option < 0)
 751                                 return 0;
 752                         mnt->bsize = option;
 753                         break;
 754                 case Opt_timeo:
 755                         if (match_int(args, &mnt->timeo))
 756                                 return 0;
 757                         break;
 758                 case Opt_retrans:
 759                         if (match_int(args, &mnt->retrans))
 760                                 return 0;
 761                         break;
 762                 case Opt_acregmin:
 763                         if (match_int(args, &mnt->acregmin))
 764                                 return 0;
 765                         break;
 766                 case Opt_acregmax:
 767                         if (match_int(args, &mnt->acregmax))
 768                                 return 0;
 769                         break;
 770                 case Opt_acdirmin:
 771                         if (match_int(args, &mnt->acdirmin))
 772                                 return 0;
 773                         break;
 774                 case Opt_acdirmax:
 775                         if (match_int(args, &mnt->acdirmax))
 776                                 return 0;
 777                         break;
 778                 case Opt_actimeo:
 779                         if (match_int(args, &option))
 780                                 return 0;
 781                         if (option < 0)
 782                                 return 0;
 783                         mnt->acregmin =
 784                         mnt->acregmax =
 785                         mnt->acdirmin =
 786                         mnt->acdirmax = option;
 787                         break;
 788                 case Opt_namelen:
 789                         if (match_int(args, &mnt->namlen))
 790                                 return 0;
 791                         break;
 792                 case Opt_mountport:
 793                         if (match_int(args, &option))
 794                                 return 0;
 795                         if (option < 0 || option > 65535)
 796                                 return 0;
 797                         mnt->mount_server.port = option;
 798                         break;
 799                 case Opt_mountprog:
 800                         if (match_int(args, &option))
 801                                 return 0;
 802                         if (option < 0)
 803                                 return 0;
 804                         mnt->mount_server.program = option;
 805                         break;
 806                 case Opt_mountvers:
 807                         if (match_int(args, &option))
 808                                 return 0;
 809                         if (option < 0)
 810                                 return 0;
 811                         mnt->mount_server.version = option;
 812                         break;
 813                 case Opt_nfsprog:
 814                         if (match_int(args, &option))
 815                                 return 0;
 816                         if (option < 0)
 817                                 return 0;
 818                         mnt->nfs_server.program = option;
 819                         break;
 820                 case Opt_nfsvers:
 821                         if (match_int(args, &option))
 822                                 return 0;
 823                         switch (option) {
 824                         case 2:
 825                                 mnt->flags &= ~NFS_MOUNT_VER3;
 826                                 break;
 827                         case 3:
 828                                 mnt->flags |= NFS_MOUNT_VER3;
 829                                 break;
 830                         default:
 831                                 goto out_unrec_vers;
 832                         }
 833                         break;
 834
 835                 case Opt_sec:
 836                         string = match_strdup(args);
 837                         if (string == NULL)
 838                                 goto out_nomem;
 839                         token = match_token(string, nfs_secflavor_tokens, args);
 840                         kfree(string);
 841
 842                         /*
 843                          * The flags setting is for v2/v3.  The flavor_len
 844                          * setting is for v4.  v2/v3 also need to know the
 845                          * difference between NULL and UNIX.
 846                          */
 847                         switch (token) {
 848                         case Opt_sec_none:
 849                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 850                                 mnt->auth_flavor_len = 0;
 851                                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 852                                 break;
 853                         case Opt_sec_sys:
 854                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 855                                 mnt->auth_flavor_len = 0;
 856                                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 857                                 break;
 858                         case Opt_sec_krb5:
 859                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 860                                 mnt->auth_flavor_len = 1;
 861                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 862                                 break;
 863                         case Opt_sec_krb5i:
 864                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 865                                 mnt->auth_flavor_len = 1;
 866                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 867                                 break;
 868                         case Opt_sec_krb5p:
 869                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 870                                 mnt->auth_flavor_len = 1;
 871                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 872                                 break;
 873                         case Opt_sec_lkey:
 874                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 875                                 mnt->auth_flavor_len = 1;
 876                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 877                                 break;
 878                         case Opt_sec_lkeyi:
 879                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 880                                 mnt->auth_flavor_len = 1;
 881                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 882                                 break;
 883                         case Opt_sec_lkeyp:
 884                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 885                                 mnt->auth_flavor_len = 1;
 886                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 887                                 break;
 888                         case Opt_sec_spkm:
 889                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 890                                 mnt->auth_flavor_len = 1;
 891                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 892                                 break;
 893                         case Opt_sec_spkmi:
 894                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 895                                 mnt->auth_flavor_len = 1;
 896                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 897                                 break;
 898                         case Opt_sec_spkmp:
 899                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 900                                 mnt->auth_flavor_len = 1;
 901                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 902                                 break;
 903                         default:
 904                                 goto out_unrec_sec;
 905                         }
 906                         break;
 907                 case Opt_proto:
 908                         string = match_strdup(args);
 909                         if (string == NULL)
 910                                 goto out_nomem;
 911                         token = match_token(string,
 912                                             nfs_xprt_protocol_tokens, args);
 913                         kfree(string);
 914
 915                         switch (token) {
 916                         case Opt_xprt_udp:
 917                                 mnt->flags &= ~NFS_MOUNT_TCP;
 918                                 mnt->nfs_server.protocol = IPPROTO_UDP;
 919                                 mnt->timeo = 7;
 920                                 mnt->retrans = 5;
 921                                 break;
 922                         case Opt_xprt_tcp:
 923                                 mnt->flags |= NFS_MOUNT_TCP;
 924                                 mnt->nfs_server.protocol = IPPROTO_TCP;
 925                                 mnt->timeo = 600;
 926                                 mnt->retrans = 2;
 927                                 break;
 928                         default:
 929                                 goto out_unrec_xprt;
 930                         }
 931                         break;
 932                 case Opt_mountproto:
 933                         string = match_strdup(args);
 934                         if (string == NULL)
 935                                 goto out_nomem;
 936                         token = match_token(string,
 937                                             nfs_xprt_protocol_tokens, args);
 938                         kfree(string);
 939
 940                         switch (token) {
 941                         case Opt_xprt_udp:
 942                                 mnt->mount_server.protocol = IPPROTO_UDP;
 943                                 break;
 944                         case Opt_xprt_tcp:
 945                                 mnt->mount_server.protocol = IPPROTO_TCP;
 946                                 break;
 947                         default:
 948                                 goto out_unrec_xprt;
 949                         }
 950                         break;
 951                 case Opt_addr:
 952                         string = match_strdup(args);
 953                         if (string == NULL)
 954                                 goto out_nomem;
 955                         mnt->nfs_server.address.sin_family = AF_INET;
 956                         mnt->nfs_server.address.sin_addr.s_addr =
 957                                                         in_aton(string);
 958                         kfree(string);
 959                         break;
 960                 case Opt_clientaddr:
 961                         string = match_strdup(args);
 962                         if (string == NULL)
 963                                 goto out_nomem;
 964                         mnt->client_address = string;
 965                         break;
 966                 case Opt_mountaddr:
 967                         string = match_strdup(args);
 968                         if (string == NULL)
 969                                 goto out_nomem;
 970                         mnt->mount_server.address.sin_family = AF_INET;
 971                         mnt->mount_server.address.sin_addr.s_addr =
 972                                                         in_aton(string);
 973                         kfree(string);
 974                         break;
 975
 976                 case Opt_userspace:
 977                 case Opt_deprecated:
 978                         break;
 979
 980                 default:
 981                         goto out_unknown;
 982                 }
 983         }
 984
 985         return 1;
 986
 987 out_nomem:
 988         printk(KERN_INFO "NFS: not enough memory to parse option\n");
 989         return 0;
 990
 991 out_unrec_vers:
 992         printk(KERN_INFO "NFS: unrecognized NFS version number\n");
 993         return 0;
 994
 995 out_unrec_xprt:
 996         printk(KERN_INFO "NFS: unrecognized transport protocol\n");
 997         return 0;
 998
 999 out_unrec_sec:
1000         printk(KERN_INFO "NFS: unrecognized security flavor\n");
1001         return 0;
1002
1003 out_unknown:
1004         printk(KERN_INFO "NFS: unknown mount option: %s\n", p);
1005         return 0;
1006 }
1007
1008 /*
1009  * Use the remote server's MOUNT service to request the NFS file handle
1010  * corresponding to the provided path.
1011  */
1012 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1013                          struct nfs_fh *root_fh)
1014 {
1015         struct sockaddr_in sin;
1016         int status;
1017
1018         if (args->mount_server.version == 0) {
1019                 if (args->flags & NFS_MOUNT_VER3)
1020                         args->mount_server.version = NFS_MNT3_VERSION;
1021                 else
1022                         args->mount_server.version = NFS_MNT_VERSION;
1023         }
1024
1025         /*
1026          * Construct the mount server's address.
1027          */
1028         if (args->mount_server.address.sin_addr.s_addr != INADDR_ANY)
1029                 sin = args->mount_server.address;
1030         else
1031                 sin = args->nfs_server.address;
1032         /*
1033          * autobind will be used if mount_server.port == 0
1034          */
1035         sin.sin_port = htons(args->mount_server.port);
1036
1037         /*
1038          * Now ask the mount server to map our export path
1039          * to a file handle.
1040          */
1041         status = nfs_mount((struct sockaddr *) &sin,
1042                            sizeof(sin),
1043                            args->nfs_server.hostname,
1044                            args->nfs_server.export_path,
1045                            args->mount_server.version,
1046                            args->mount_server.protocol,
1047                            root_fh);
1048         if (status == 0)
1049                 return 0;
1050
1051         dfprintk(MOUNT, "NFS: unable to mount server " NIPQUAD_FMT
1052                         ", error %d\n", NIPQUAD(sin.sin_addr.s_addr), status);
1053         return status;
1054 }
1055
1056 /*
1057  * Validate the NFS2/NFS3 mount data
1058  * - fills in the mount root filehandle
1059  *
1060  * For option strings, user space handles the following behaviors:
1061  *
1062  * + DNS: mapping server host name to IP address ("addr=" option)
1063  *
1064  * + failure mode: how to behave if a mount request can't be handled
1065  *   immediately ("fg/bg" option)
1066  *
1067  * + retry: how often to retry a mount request ("retry=" option)
1068  *
1069  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1070  *   mountproto=tcp after mountproto=udp, and so on
1071  *
1072  * XXX: as far as I can tell, changing the NFS program number is not
1073  *      supported in the NFS client.
1074  */
1075 static int nfs_validate_mount_data(struct nfs_mount_data **options,
1076                                    struct nfs_fh *mntfh,
1077                                    const char *dev_name)
1078 {
1079         struct nfs_mount_data *data = *options;
1080
1081         if (data == NULL)
1082                 goto out_no_data;
1083
1084         switch (data->version) {
1085         case 1:
1086                 data->namlen = 0;
1087         case 2:
1088                 data->bsize = 0;
1089         case 3:
1090                 if (data->flags & NFS_MOUNT_VER3)
1091                         goto out_no_v3;
1092                 data->root.size = NFS2_FHSIZE;
1093                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1094         case 4:
1095                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1096                         goto out_no_sec;
1097         case 5:
1098                 memset(data->context, 0, sizeof(data->context));
1099         case 6:
1100                 if (data->flags & NFS_MOUNT_VER3)
1101                         mntfh->size = data->root.size;
1102                 else
1103                         mntfh->size = NFS2_FHSIZE;
1104
1105                 if (mntfh->size > sizeof(mntfh->data))
1106                         goto out_invalid_fh;
1107
1108                 memcpy(mntfh->data, data->root.data, mntfh->size);
1109                 if (mntfh->size < sizeof(mntfh->data))
1110                         memset(mntfh->data + mntfh->size, 0,
1111                                sizeof(mntfh->data) - mntfh->size);
1112                 break;
1113         default: {
1114                 unsigned int len;
1115                 char *c;
1116                 int status;
1117                 struct nfs_parsed_mount_data args = {
1118                         .flags          = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP),
1119                         .rsize          = NFS_MAX_FILE_IO_SIZE,
1120                         .wsize          = NFS_MAX_FILE_IO_SIZE,
1121                         .timeo          = 600,
1122                         .retrans        = 2,
1123                         .acregmin       = 3,
1124                         .acregmax       = 60,
1125                         .acdirmin       = 30,
1126                         .acdirmax       = 60,
1127                         .mount_server.protocol = IPPROTO_UDP,
1128                         .mount_server.program = NFS_MNT_PROGRAM,
1129                         .nfs_server.protocol = IPPROTO_TCP,
1130                         .nfs_server.program = NFS_PROGRAM,
1131                 };
1132
1133                 if (nfs_parse_mount_options((char *) *options, &args) == 0)
1134                         return -EINVAL;
1135
1136                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1137                 if (data == NULL)
1138                         return -ENOMEM;
1139
1140                 /*
1141                  * NB: after this point, caller will free "data"
1142                  * if we return an error
1143                  */
1144                 *options = data;
1145
1146                 c = strchr(dev_name, ':');
1147                 if (c == NULL)
1148                         return -EINVAL;
1149                 len = c - dev_name;
1150                 if (len > sizeof(data->hostname))
1151                         return -ENAMETOOLONG;
1152                 strncpy(data->hostname, dev_name, len);
1153                 args.nfs_server.hostname = data->hostname;
1154
1155                 c++;
1156                 if (strlen(c) > NFS_MAXPATHLEN)
1157                         return -ENAMETOOLONG;
1158                 args.nfs_server.export_path = c;
1159
1160                 status = nfs_try_mount(&args, mntfh);
1161                 if (status)
1162                         return status;
1163
1164                 /*
1165                  * Translate to nfs_mount_data, which nfs_fill_super
1166                  * can deal with.
1167                  */
1168                 data->version           = 6;
1169                 data->flags             = args.flags;
1170                 data->rsize             = args.rsize;
1171                 data->wsize             = args.wsize;
1172                 data->timeo             = args.timeo;
1173                 data->retrans           = args.retrans;
1174                 data->acregmin          = args.acregmin;
1175                 data->acregmax          = args.acregmax;
1176                 data->acdirmin          = args.acdirmin;
1177                 data->acdirmax          = args.acdirmax;
1178                 data->addr              = args.nfs_server.address;
1179                 data->namlen            = args.namlen;
1180                 data->bsize             = args.bsize;
1181                 data->pseudoflavor      = args.auth_flavors[0];
1182
1183                 break;
1184                 }
1185         }
1186
1187         if (!(data->flags & NFS_MOUNT_SECFLAVOUR))
1188                 data->pseudoflavor = RPC_AUTH_UNIX;
1189
1190 #ifndef CONFIG_NFS_V3
1191         if (data->flags & NFS_MOUNT_VER3)
1192                 goto out_v3_not_compiled;
1193 #endif /* !CONFIG_NFS_V3 */
1194
1195         if (!nfs_verify_server_address((struct sockaddr *) &data->addr))
1196                 goto out_no_address;
1197
1198         return 0;
1199
1200 out_no_data:
1201         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1202         return -EINVAL;
1203
1204 out_no_v3:
1205         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1206                  data->version);
1207         return -EINVAL;
1208
1209 out_no_sec:
1210         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1211         return -EINVAL;
1212
1213 #ifndef CONFIG_NFS_V3
1214 out_v3_not_compiled:
1215         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1216         return -EPROTONOSUPPORT;
1217 #endif /* !CONFIG_NFS_V3 */
1218
1219 out_no_address:
1220         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1221         return -EINVAL;
1222
1223 out_invalid_fh:
1224         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1225         return -EINVAL;
1226 }
1227
1228 /*
1229  * Initialise the common bits of the superblock
1230  */
1231 static inline void nfs_initialise_sb(struct super_block *sb)
1232 {
1233         struct nfs_server *server = NFS_SB(sb);
1234
1235         sb->s_magic = NFS_SUPER_MAGIC;
1236
1237         /* We probably want something more informative here */
1238         snprintf(sb->s_id, sizeof(sb->s_id),
1239                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1240
1241         if (sb->s_blocksize == 0)
1242                 sb->s_blocksize = nfs_block_bits(server->wsize,
1243                                                  &sb->s_blocksize_bits);
1244
1245         if (server->flags & NFS_MOUNT_NOAC)
1246                 sb->s_flags |= MS_SYNCHRONOUS;
1247
1248         nfs_super_set_maxbytes(sb, server->maxfilesize);
1249 }
1250
1251 /*
1252  * Finish setting up an NFS2/3 superblock
1253  */
1254 static void nfs_fill_super(struct super_block *sb, struct nfs_mount_data *data)
1255 {
1256         struct nfs_server *server = NFS_SB(sb);
1257
1258         sb->s_blocksize_bits = 0;
1259         sb->s_blocksize = 0;
1260         if (data->bsize)
1261                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1262
1263         if (server->flags & NFS_MOUNT_VER3) {
1264                 /* The VFS shouldn't apply the umask to mode bits. We will do
1265                  * so ourselves when necessary.
1266                  */
1267                 sb->s_flags |= MS_POSIXACL;
1268                 sb->s_time_gran = 1;
1269         }
1270
1271         sb->s_op = &nfs_sops;
1272         nfs_initialise_sb(sb);
1273 }
1274
1275 /*
1276  * Finish setting up a cloned NFS2/3 superblock
1277  */
1278 static void nfs_clone_super(struct super_block *sb,
1279                             const struct super_block *old_sb)
1280 {
1281         struct nfs_server *server = NFS_SB(sb);
1282
1283         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1284         sb->s_blocksize = old_sb->s_blocksize;
1285         sb->s_maxbytes = old_sb->s_maxbytes;
1286
1287         if (server->flags & NFS_MOUNT_VER3) {
1288                 /* The VFS shouldn't apply the umask to mode bits. We will do
1289                  * so ourselves when necessary.
1290                  */
1291                 sb->s_flags |= MS_POSIXACL;
1292                 sb->s_time_gran = 1;
1293         }
1294
1295         sb->s_op = old_sb->s_op;
1296         nfs_initialise_sb(sb);
1297 }
1298
1299 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1300
1301 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1302 {
1303         const struct nfs_server *a = s->s_fs_info;
1304         const struct rpc_clnt *clnt_a = a->client;
1305         const struct rpc_clnt *clnt_b = b->client;
1306
1307         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1308                 goto Ebusy;
1309         if (a->nfs_client != b->nfs_client)
1310                 goto Ebusy;
1311         if (a->flags != b->flags)
1312                 goto Ebusy;
1313         if (a->wsize != b->wsize)
1314                 goto Ebusy;
1315         if (a->rsize != b->rsize)
1316                 goto Ebusy;
1317         if (a->acregmin != b->acregmin)
1318                 goto Ebusy;
1319         if (a->acregmax != b->acregmax)
1320                 goto Ebusy;
1321         if (a->acdirmin != b->acdirmin)
1322                 goto Ebusy;
1323         if (a->acdirmax != b->acdirmax)
1324                 goto Ebusy;
1325         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1326                 goto Ebusy;
1327         return 1;
1328 Ebusy:
1329         return 0;
1330 }
1331
1332 struct nfs_sb_mountdata {
1333         struct nfs_server *server;
1334         int mntflags;
1335 };
1336
1337 static int nfs_set_super(struct super_block *s, void *data)
1338 {
1339         struct nfs_sb_mountdata *sb_mntdata = data;
1340         struct nfs_server *server = sb_mntdata->server;
1341         int ret;
1342
1343         s->s_flags = sb_mntdata->mntflags;
1344         s->s_fs_info = server;
1345         ret = set_anon_super(s, server);
1346         if (ret == 0)
1347                 server->s_dev = s->s_dev;
1348         return ret;
1349 }
1350
1351 static int nfs_compare_super(struct super_block *sb, void *data)
1352 {
1353         struct nfs_sb_mountdata *sb_mntdata = data;
1354         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1355         int mntflags = sb_mntdata->mntflags;
1356
1357         if (memcmp(&old->nfs_client->cl_addr,
1358                                 &server->nfs_client->cl_addr,
1359                                 sizeof(old->nfs_client->cl_addr)) != 0)
1360                 return 0;
1361         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1362         if (old->flags & NFS_MOUNT_UNSHARED)
1363                 return 0;
1364         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1365                 return 0;
1366         return nfs_compare_mount_options(sb, server, mntflags);
1367 }
1368
1369 static int nfs_get_sb(struct file_system_type *fs_type,
1370         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1371 {
1372         struct nfs_server *server = NULL;
1373         struct super_block *s;
1374         struct nfs_fh mntfh;
1375         struct nfs_mount_data *data = raw_data;
1376         struct dentry *mntroot;
1377         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1378         struct nfs_sb_mountdata sb_mntdata = {
1379                 .mntflags = flags,
1380         };
1381         int error;
1382
1383         /* Validate the mount data */
1384         error = nfs_validate_mount_data(&data, &mntfh, dev_name);
1385         if (error < 0)
1386                 goto out;
1387
1388         /* Get a volume representation */
1389         server = nfs_create_server(data, &mntfh);
1390         if (IS_ERR(server)) {
1391                 error = PTR_ERR(server);
1392                 goto out;
1393         }
1394         sb_mntdata.server = server;
1395
1396         if (server->flags & NFS_MOUNT_UNSHARED)
1397                 compare_super = NULL;
1398
1399         /* Get a superblock - note that we may end up sharing one that already exists */
1400         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1401         if (IS_ERR(s)) {
1402                 error = PTR_ERR(s);
1403                 goto out_err_nosb;
1404         }
1405
1406         if (s->s_fs_info != server) {
1407                 nfs_free_server(server);
1408                 server = NULL;
1409         }
1410
1411         if (!s->s_root) {
1412                 /* initial superblock/root creation */
1413                 nfs_fill_super(s, data);
1414         }
1415
1416         mntroot = nfs_get_root(s, &mntfh);
1417         if (IS_ERR(mntroot)) {
1418                 error = PTR_ERR(mntroot);
1419                 goto error_splat_super;
1420         }
1421
1422         s->s_flags |= MS_ACTIVE;
1423         mnt->mnt_sb = s;
1424         mnt->mnt_root = mntroot;
1425         error = 0;
1426
1427 out:
1428         if (data != raw_data)
1429                 kfree(data);
1430         return error;
1431
1432 out_err_nosb:
1433         nfs_free_server(server);
1434         goto out;
1435
1436 error_splat_super:
1437         up_write(&s->s_umount);
1438         deactivate_super(s);
1439         goto out;
1440 }
1441
1442 /*
1443  * Destroy an NFS2/3 superblock
1444  */
1445 static void nfs_kill_super(struct super_block *s)
1446 {
1447         struct nfs_server *server = NFS_SB(s);
1448
1449         kill_anon_super(s);
1450         nfs_free_server(server);
1451 }
1452
1453 /*
1454  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
1455  */
1456 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
1457                            const char *dev_name, void *raw_data,
1458                            struct vfsmount *mnt)
1459 {
1460         struct nfs_clone_mount *data = raw_data;
1461         struct super_block *s;
1462         struct nfs_server *server;
1463         struct dentry *mntroot;
1464         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1465         struct nfs_sb_mountdata sb_mntdata = {
1466                 .mntflags = flags,
1467         };
1468         int error;
1469
1470         dprintk("--> nfs_xdev_get_sb()\n");
1471
1472         /* create a new volume representation */
1473         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1474         if (IS_ERR(server)) {
1475                 error = PTR_ERR(server);
1476                 goto out_err_noserver;
1477         }
1478         sb_mntdata.server = server;
1479
1480         if (server->flags & NFS_MOUNT_UNSHARED)
1481                 compare_super = NULL;
1482
1483         /* Get a superblock - note that we may end up sharing one that already exists */
1484         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1485         if (IS_ERR(s)) {
1486                 error = PTR_ERR(s);
1487                 goto out_err_nosb;
1488         }
1489
1490         if (s->s_fs_info != server) {
1491                 nfs_free_server(server);
1492                 server = NULL;
1493         }
1494
1495         if (!s->s_root) {
1496                 /* initial superblock/root creation */
1497                 nfs_clone_super(s, data->sb);
1498         }
1499
1500         mntroot = nfs_get_root(s, data->fh);
1501         if (IS_ERR(mntroot)) {
1502                 error = PTR_ERR(mntroot);
1503                 goto error_splat_super;
1504         }
1505
1506         s->s_flags |= MS_ACTIVE;
1507         mnt->mnt_sb = s;
1508         mnt->mnt_root = mntroot;
1509
1510         dprintk("<-- nfs_xdev_get_sb() = 0\n");
1511         return 0;
1512
1513 out_err_nosb:
1514         nfs_free_server(server);
1515 out_err_noserver:
1516         dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
1517         return error;
1518
1519 error_splat_super:
1520         up_write(&s->s_umount);
1521         deactivate_super(s);
1522         dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
1523         return error;
1524 }
1525
1526 #ifdef CONFIG_NFS_V4
1527
1528 /*
1529  * Finish setting up a cloned NFS4 superblock
1530  */
1531 static void nfs4_clone_super(struct super_block *sb,
1532                             const struct super_block *old_sb)
1533 {
1534         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1535         sb->s_blocksize = old_sb->s_blocksize;
1536         sb->s_maxbytes = old_sb->s_maxbytes;
1537         sb->s_time_gran = 1;
1538         sb->s_op = old_sb->s_op;
1539         nfs_initialise_sb(sb);
1540 }
1541
1542 /*
1543  * Set up an NFS4 superblock
1544  */
1545 static void nfs4_fill_super(struct super_block *sb)
1546 {
1547         sb->s_time_gran = 1;
1548         sb->s_op = &nfs4_sops;
1549         nfs_initialise_sb(sb);
1550 }
1551
1552 /*
1553  * Validate NFSv4 mount options
1554  */
1555 static int nfs4_validate_mount_data(struct nfs4_mount_data **options,
1556                                     const char *dev_name,
1557                                     struct sockaddr_in *addr,
1558                                     rpc_authflavor_t *authflavour,
1559                                     char **hostname,
1560                                     char **mntpath,
1561                                     char **ip_addr)
1562 {
1563         struct nfs4_mount_data *data = *options;
1564         char *c;
1565
1566         if (data == NULL)
1567                 goto out_no_data;
1568
1569         switch (data->version) {
1570         case 1:
1571                 if (data->host_addrlen != sizeof(*addr))
1572                         goto out_no_address;
1573                 if (copy_from_user(addr, data->host_addr, sizeof(*addr)))
1574                         return -EFAULT;
1575                 if (addr->sin_port == 0)
1576                         addr->sin_port = htons(NFS_PORT);
1577                 if (!nfs_verify_server_address((struct sockaddr *) addr))
1578                         goto out_no_address;
1579
1580                 switch (data->auth_flavourlen) {
1581                 case 0:
1582                         *authflavour = RPC_AUTH_UNIX;
1583                         break;
1584                 case 1:
1585                         if (copy_from_user(authflavour, data->auth_flavours,
1586                                            sizeof(*authflavour)))
1587                                 return -EFAULT;
1588                         break;
1589                 default:
1590                         goto out_inval_auth;
1591                 }
1592
1593                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
1594                 if (IS_ERR(c))
1595                         return PTR_ERR(c);
1596                 *hostname = c;
1597
1598                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
1599                 if (IS_ERR(c))
1600                         return PTR_ERR(c);
1601                 *mntpath = c;
1602                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *mntpath);
1603
1604                 c = strndup_user(data->client_addr.data, 16);
1605                 if (IS_ERR(c))
1606                         return PTR_ERR(c);
1607                 *ip_addr = c;
1608
1609                 break;
1610         default: {
1611                 unsigned int len;
1612                 struct nfs_parsed_mount_data args = {
1613                         .rsize          = NFS_MAX_FILE_IO_SIZE,
1614                         .wsize          = NFS_MAX_FILE_IO_SIZE,
1615                         .timeo          = 600,
1616                         .retrans        = 2,
1617                         .acregmin       = 3,
1618                         .acregmax       = 60,
1619                         .acdirmin       = 30,
1620                         .acdirmax       = 60,
1621                         .nfs_server.protocol = IPPROTO_TCP,
1622                 };
1623
1624                 if (nfs_parse_mount_options((char *) *options, &args) == 0)
1625                         return -EINVAL;
1626
1627                 if (!nfs_verify_server_address((struct sockaddr *)
1628                                                 &args.nfs_server.address))
1629                         return -EINVAL;
1630                 *addr = args.nfs_server.address;
1631
1632                 switch (args.auth_flavor_len) {
1633                 case 0:
1634                         *authflavour = RPC_AUTH_UNIX;
1635                         break;
1636                 case 1:
1637                         *authflavour = (rpc_authflavor_t) args.auth_flavors[0];
1638                         break;
1639                 default:
1640                         goto out_inval_auth;
1641                 }
1642
1643                 /*
1644                  * Translate to nfs4_mount_data, which nfs4_fill_super
1645                  * can deal with.
1646                  */
1647                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1648                 if (data == NULL)
1649                         return -ENOMEM;
1650                 *options = data;
1651
1652                 data->version   = 1;
1653                 data->flags     = args.flags & NFS4_MOUNT_FLAGMASK;
1654                 data->rsize     = args.rsize;
1655                 data->wsize     = args.wsize;
1656                 data->timeo     = args.timeo;
1657                 data->retrans   = args.retrans;
1658                 data->acregmin  = args.acregmin;
1659                 data->acregmax  = args.acregmax;
1660                 data->acdirmin  = args.acdirmin;
1661                 data->acdirmax  = args.acdirmax;
1662                 data->proto     = args.nfs_server.protocol;
1663
1664                 /*
1665                  * Split "dev_name" into "hostname:mntpath".
1666                  */
1667                 c = strchr(dev_name, ':');
1668                 if (c == NULL)
1669                         return -EINVAL;
1670                 /* while calculating len, pretend ':' is '\0' */
1671                 len = c - dev_name;
1672                 if (len > NFS4_MAXNAMLEN)
1673                         return -ENAMETOOLONG;
1674                 *hostname = kzalloc(len, GFP_KERNEL);
1675                 if (*hostname == NULL)
1676                         return -ENOMEM;
1677                 strncpy(*hostname, dev_name, len - 1);
1678
1679                 c++;                    /* step over the ':' */
1680                 len = strlen(c);
1681                 if (len > NFS4_MAXPATHLEN)
1682                         return -ENAMETOOLONG;
1683                 *mntpath = kzalloc(len + 1, GFP_KERNEL);
1684                 if (*mntpath == NULL)
1685                         return -ENOMEM;
1686                 strncpy(*mntpath, c, len);
1687
1688                 dprintk("MNTPATH: %s\n", *mntpath);
1689
1690                 if (args.client_address == NULL)
1691                         goto out_no_client_address;
1692
1693                 *ip_addr = args.client_address;
1694
1695                 break;
1696                 }
1697         }
1698
1699         return 0;
1700
1701 out_no_data:
1702         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
1703         return -EINVAL;
1704
1705 out_inval_auth:
1706         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
1707                  data->auth_flavourlen);
1708         return -EINVAL;
1709
1710 out_no_address:
1711         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
1712         return -EINVAL;
1713
1714 out_no_client_address:
1715         dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
1716         return -EINVAL;
1717 }
1718
1719 /*
1720  * Get the superblock for an NFS4 mountpoint
1721  */
1722 static int nfs4_get_sb(struct file_system_type *fs_type,
1723         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1724 {
1725         struct nfs4_mount_data *data = raw_data;
1726         struct super_block *s;
1727         struct nfs_server *server;
1728         struct sockaddr_in addr;
1729         rpc_authflavor_t authflavour;
1730         struct nfs_fh mntfh;
1731         struct dentry *mntroot;
1732         char *mntpath = NULL, *hostname = NULL, *ip_addr = NULL;
1733         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1734         struct nfs_sb_mountdata sb_mntdata = {
1735                 .mntflags = flags,
1736         };
1737         int error;
1738
1739         /* Validate the mount data */
1740         error = nfs4_validate_mount_data(&data, dev_name, &addr, &authflavour,
1741                                          &hostname, &mntpath, &ip_addr);
1742         if (error < 0)
1743                 goto out;
1744
1745         /* Get a volume representation */
1746         server = nfs4_create_server(data, hostname, &addr, mntpath, ip_addr,
1747                                     authflavour, &mntfh);
1748         if (IS_ERR(server)) {
1749                 error = PTR_ERR(server);
1750                 goto out;
1751         }
1752         sb_mntdata.server = server;
1753
1754         if (server->flags & NFS4_MOUNT_UNSHARED)
1755                 compare_super = NULL;
1756
1757         /* Get a superblock - note that we may end up sharing one that already exists */
1758         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1759         if (IS_ERR(s)) {
1760                 error = PTR_ERR(s);
1761                 goto out_free;
1762         }
1763
1764         if (s->s_fs_info != server) {
1765                 nfs_free_server(server);
1766                 server = NULL;
1767         }
1768
1769         if (!s->s_root) {
1770                 /* initial superblock/root creation */
1771                 nfs4_fill_super(s);
1772         }
1773
1774         mntroot = nfs4_get_root(s, &mntfh);
1775         if (IS_ERR(mntroot)) {
1776                 error = PTR_ERR(mntroot);
1777                 goto error_splat_super;
1778         }
1779
1780         s->s_flags |= MS_ACTIVE;
1781         mnt->mnt_sb = s;
1782         mnt->mnt_root = mntroot;
1783         error = 0;
1784
1785 out:
1786         kfree(ip_addr);
1787         kfree(mntpath);
1788         kfree(hostname);
1789         return error;
1790
1791 out_free:
1792         nfs_free_server(server);
1793         goto out;
1794
1795 error_splat_super:
1796         up_write(&s->s_umount);
1797         deactivate_super(s);
1798         goto out;
1799 }
1800
1801 static void nfs4_kill_super(struct super_block *sb)
1802 {
1803         struct nfs_server *server = NFS_SB(sb);
1804
1805         nfs_return_all_delegations(sb);
1806         kill_anon_super(sb);
1807
1808         nfs4_renewd_prepare_shutdown(server);
1809         nfs_free_server(server);
1810 }
1811
1812 /*
1813  * Clone an NFS4 server record on xdev traversal (FSID-change)
1814  */
1815 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
1816                             const char *dev_name, void *raw_data,
1817                             struct vfsmount *mnt)
1818 {
1819         struct nfs_clone_mount *data = raw_data;
1820         struct super_block *s;
1821         struct nfs_server *server;
1822         struct dentry *mntroot;
1823         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1824         struct nfs_sb_mountdata sb_mntdata = {
1825                 .mntflags = flags,
1826         };
1827         int error;
1828
1829         dprintk("--> nfs4_xdev_get_sb()\n");
1830
1831         /* create a new volume representation */
1832         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1833         if (IS_ERR(server)) {
1834                 error = PTR_ERR(server);
1835                 goto out_err_noserver;
1836         }
1837         sb_mntdata.server = server;
1838
1839         if (server->flags & NFS4_MOUNT_UNSHARED)
1840                 compare_super = NULL;
1841
1842         /* Get a superblock - note that we may end up sharing one that already exists */
1843         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1844         if (IS_ERR(s)) {
1845                 error = PTR_ERR(s);
1846                 goto out_err_nosb;
1847         }
1848
1849         if (s->s_fs_info != server) {
1850                 nfs_free_server(server);
1851                 server = NULL;
1852         }
1853
1854         if (!s->s_root) {
1855                 /* initial superblock/root creation */
1856                 nfs4_clone_super(s, data->sb);
1857         }
1858
1859         mntroot = nfs4_get_root(s, data->fh);
1860         if (IS_ERR(mntroot)) {
1861                 error = PTR_ERR(mntroot);
1862                 goto error_splat_super;
1863         }
1864
1865         s->s_flags |= MS_ACTIVE;
1866         mnt->mnt_sb = s;
1867         mnt->mnt_root = mntroot;
1868
1869         dprintk("<-- nfs4_xdev_get_sb() = 0\n");
1870         return 0;
1871
1872 out_err_nosb:
1873         nfs_free_server(server);
1874 out_err_noserver:
1875         dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
1876         return error;
1877
1878 error_splat_super:
1879         up_write(&s->s_umount);
1880         deactivate_super(s);
1881         dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
1882         return error;
1883 }
1884
1885 /*
1886  * Create an NFS4 server record on referral traversal
1887  */
1888 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
1889                                 const char *dev_name, void *raw_data,
1890                                 struct vfsmount *mnt)
1891 {
1892         struct nfs_clone_mount *data = raw_data;
1893         struct super_block *s;
1894         struct nfs_server *server;
1895         struct dentry *mntroot;
1896         struct nfs_fh mntfh;
1897         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1898         struct nfs_sb_mountdata sb_mntdata = {
1899                 .mntflags = flags,
1900         };
1901         int error;
1902
1903         dprintk("--> nfs4_referral_get_sb()\n");
1904
1905         /* create a new volume representation */
1906         server = nfs4_create_referral_server(data, &mntfh);
1907         if (IS_ERR(server)) {
1908                 error = PTR_ERR(server);
1909                 goto out_err_noserver;
1910         }
1911         sb_mntdata.server = server;
1912
1913         if (server->flags & NFS4_MOUNT_UNSHARED)
1914                 compare_super = NULL;
1915
1916         /* Get a superblock - note that we may end up sharing one that already exists */
1917         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1918         if (IS_ERR(s)) {
1919                 error = PTR_ERR(s);
1920                 goto out_err_nosb;
1921         }
1922
1923         if (s->s_fs_info != server) {
1924                 nfs_free_server(server);
1925                 server = NULL;
1926         }
1927
1928         if (!s->s_root) {
1929                 /* initial superblock/root creation */
1930                 nfs4_fill_super(s);
1931         }
1932
1933         mntroot = nfs4_get_root(s, &mntfh);
1934         if (IS_ERR(mntroot)) {
1935                 error = PTR_ERR(mntroot);
1936                 goto error_splat_super;
1937         }
1938
1939         s->s_flags |= MS_ACTIVE;
1940         mnt->mnt_sb = s;
1941         mnt->mnt_root = mntroot;
1942
1943         dprintk("<-- nfs4_referral_get_sb() = 0\n");
1944         return 0;
1945
1946 out_err_nosb:
1947         nfs_free_server(server);
1948 out_err_noserver:
1949         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
1950         return error;
1951
1952 error_splat_super:
1953         up_write(&s->s_umount);
1954         deactivate_super(s);
1955         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
1956         return error;
1957 }
1958
1959 #endif /* CONFIG_NFS_V4 */