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   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_mountvers,
  87         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_mountvers, "mountvers=%u" },
 141         { Opt_nfsvers, "nfsvers=%u" },
 142         { Opt_nfsvers, "vers=%u" },
 143
 144         { Opt_sec, "sec=%s" },
 145         { Opt_proto, "proto=%s" },
 146         { Opt_mountproto, "mountproto=%s" },
 147         { Opt_addr, "addr=%s" },
 148         { Opt_clientaddr, "clientaddr=%s" },
 149         { Opt_userspace, "mounthost=%s" },
 150         { Opt_mountaddr, "mountaddr=%s" },
 151
 152         { Opt_err, NULL }
 153 };
 154
 155 enum {
 156         Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
 157
 158         Opt_xprt_err
 159 };
 160
 161 static match_table_t nfs_xprt_protocol_tokens = {
 162         { Opt_xprt_udp, "udp" },
 163         { Opt_xprt_tcp, "tcp" },
 164         { Opt_xprt_rdma, "rdma" },
 165
 166         { Opt_xprt_err, NULL }
 167 };
 168
 169 enum {
 170         Opt_sec_none, Opt_sec_sys,
 171         Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
 172         Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
 173         Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
 174
 175         Opt_sec_err
 176 };
 177
 178 static match_table_t nfs_secflavor_tokens = {
 179         { Opt_sec_none, "none" },
 180         { Opt_sec_none, "null" },
 181         { Opt_sec_sys, "sys" },
 182
 183         { Opt_sec_krb5, "krb5" },
 184         { Opt_sec_krb5i, "krb5i" },
 185         { Opt_sec_krb5p, "krb5p" },
 186
 187         { Opt_sec_lkey, "lkey" },
 188         { Opt_sec_lkeyi, "lkeyi" },
 189         { Opt_sec_lkeyp, "lkeyp" },
 190
 191         { Opt_sec_err, NULL }
 192 };
 193
 194
 195 static void nfs_umount_begin(struct vfsmount *, int);
 196 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 197 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 198 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
 199 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
 200 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
 201                 int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 202 static void nfs_kill_super(struct super_block *);
 203 static void nfs_put_super(struct super_block *);
 204
 205 static struct file_system_type nfs_fs_type = {
 206         .owner          = THIS_MODULE,
 207         .name           = "nfs",
 208         .get_sb         = nfs_get_sb,
 209         .kill_sb        = nfs_kill_super,
 210         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 211 };
 212
 213 struct file_system_type nfs_xdev_fs_type = {
 214         .owner          = THIS_MODULE,
 215         .name           = "nfs",
 216         .get_sb         = nfs_xdev_get_sb,
 217         .kill_sb        = nfs_kill_super,
 218         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 219 };
 220
 221 static const struct super_operations nfs_sops = {
 222         .alloc_inode    = nfs_alloc_inode,
 223         .destroy_inode  = nfs_destroy_inode,
 224         .write_inode    = nfs_write_inode,
 225         .put_super      = nfs_put_super,
 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 void nfs_sb_active(struct nfs_server *server)
 329 {
 330         atomic_inc(&server->active);
 331 }
 332
 333 void nfs_sb_deactive(struct nfs_server *server)
 334 {
 335         if (atomic_dec_and_test(&server->active))
 336                 wake_up(&server->active_wq);
 337 }
 338
 339 static void nfs_put_super(struct super_block *sb)
 340 {
 341         struct nfs_server *server = NFS_SB(sb);
 342         /*
 343          * Make sure there are no outstanding ops to this server.
 344          * If so, wait for them to finish before allowing the
 345          * unmount to continue.
 346          */
 347         wait_event(server->active_wq, atomic_read(&server->active) == 0);
 348 }
 349
 350 /*
 351  * Deliver file system statistics to userspace
 352  */
 353 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 354 {
 355         struct nfs_server *server = NFS_SB(dentry->d_sb);
 356         unsigned char blockbits;
 357         unsigned long blockres;
 358         struct nfs_fh *fh = NFS_FH(dentry->d_inode);
 359         struct nfs_fattr fattr;
 360         struct nfs_fsstat res = {
 361                         .fattr = &fattr,
 362         };
 363         int error;
 364
 365         lock_kernel();
 366
 367         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 368         if (error < 0)
 369                 goto out_err;
 370         buf->f_type = NFS_SUPER_MAGIC;
 371
 372         /*
 373          * Current versions of glibc do not correctly handle the
 374          * case where f_frsize != f_bsize.  Eventually we want to
 375          * report the value of wtmult in this field.
 376          */
 377         buf->f_frsize = dentry->d_sb->s_blocksize;
 378
 379         /*
 380          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 381          * are reported in units of f_frsize.  Linux hasn't had
 382          * an f_frsize field in its statfs struct until recently,
 383          * thus historically Linux's sys_statfs reports these
 384          * fields in units of f_bsize.
 385          */
 386         buf->f_bsize = dentry->d_sb->s_blocksize;
 387         blockbits = dentry->d_sb->s_blocksize_bits;
 388         blockres = (1 << blockbits) - 1;
 389         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 390         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 391         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 392
 393         buf->f_files = res.tfiles;
 394         buf->f_ffree = res.afiles;
 395
 396         buf->f_namelen = server->namelen;
 397
 398         unlock_kernel();
 399         return 0;
 400
 401  out_err:
 402         dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
 403         unlock_kernel();
 404         return error;
 405 }
 406
 407 /*
 408  * Map the security flavour number to a name
 409  */
 410 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 411 {
 412         static const struct {
 413                 rpc_authflavor_t flavour;
 414                 const char *str;
 415         } sec_flavours[] = {
 416                 { RPC_AUTH_NULL, "null" },
 417                 { RPC_AUTH_UNIX, "sys" },
 418                 { RPC_AUTH_GSS_KRB5, "krb5" },
 419                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 420                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 421                 { RPC_AUTH_GSS_LKEY, "lkey" },
 422                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 423                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 424                 { RPC_AUTH_GSS_SPKM, "spkm" },
 425                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 426                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 427                 { UINT_MAX, "unknown" }
 428         };
 429         int i;
 430
 431         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 432                 if (sec_flavours[i].flavour == flavour)
 433                         break;
 434         }
 435         return sec_flavours[i].str;
 436 }
 437
 438 /*
 439  * Describe the mount options in force on this server representation
 440  */
 441 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
 442 {
 443         static const struct proc_nfs_info {
 444                 int flag;
 445                 const char *str;
 446                 const char *nostr;
 447         } nfs_info[] = {
 448                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 449                 { NFS_MOUNT_INTR, ",intr", ",nointr" },
 450                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 451                 { NFS_MOUNT_NOAC, ",noac", "" },
 452                 { NFS_MOUNT_NONLM, ",nolock", "" },
 453                 { NFS_MOUNT_NOACL, ",noacl", "" },
 454                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 455                 { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
 456                 { 0, NULL, NULL }
 457         };
 458         const struct proc_nfs_info *nfs_infop;
 459         struct nfs_client *clp = nfss->nfs_client;
 460
 461         seq_printf(m, ",vers=%d", clp->rpc_ops->version);
 462         seq_printf(m, ",rsize=%d", nfss->rsize);
 463         seq_printf(m, ",wsize=%d", nfss->wsize);
 464         if (nfss->acregmin != 3*HZ || showdefaults)
 465                 seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
 466         if (nfss->acregmax != 60*HZ || showdefaults)
 467                 seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
 468         if (nfss->acdirmin != 30*HZ || showdefaults)
 469                 seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
 470         if (nfss->acdirmax != 60*HZ || showdefaults)
 471                 seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
 472         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 473                 if (nfss->flags & nfs_infop->flag)
 474                         seq_puts(m, nfs_infop->str);
 475                 else
 476                         seq_puts(m, nfs_infop->nostr);
 477         }
 478         seq_printf(m, ",proto=%s",
 479                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
 480         seq_printf(m, ",timeo=%lu", 10U * clp->retrans_timeo / HZ);
 481         seq_printf(m, ",retrans=%u", clp->retrans_count);
 482         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 483 }
 484
 485 /*
 486  * Describe the mount options on this VFS mountpoint
 487  */
 488 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 489 {
 490         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 491
 492         nfs_show_mount_options(m, nfss, 0);
 493
 494         seq_printf(m, ",addr="NIPQUAD_FMT,
 495                 NIPQUAD(nfss->nfs_client->cl_addr.sin_addr));
 496
 497         return 0;
 498 }
 499
 500 /*
 501  * Present statistical information for this VFS mountpoint
 502  */
 503 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 504 {
 505         int i, cpu;
 506         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 507         struct rpc_auth *auth = nfss->client->cl_auth;
 508         struct nfs_iostats totals = { };
 509
 510         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 511
 512         /*
 513          * Display all mount option settings
 514          */
 515         seq_printf(m, "\n\topts:\t");
 516         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 517         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 518         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 519         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 520         nfs_show_mount_options(m, nfss, 1);
 521
 522         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 523
 524         seq_printf(m, "\n\tcaps:\t");
 525         seq_printf(m, "caps=0x%x", nfss->caps);
 526         seq_printf(m, ",wtmult=%d", nfss->wtmult);
 527         seq_printf(m, ",dtsize=%d", nfss->dtsize);
 528         seq_printf(m, ",bsize=%d", nfss->bsize);
 529         seq_printf(m, ",namelen=%d", nfss->namelen);
 530
 531 #ifdef CONFIG_NFS_V4
 532         if (nfss->nfs_client->cl_nfsversion == 4) {
 533                 seq_printf(m, "\n\tnfsv4:\t");
 534                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 535                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 536                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 537         }
 538 #endif
 539
 540         /*
 541          * Display security flavor in effect for this mount
 542          */
 543         seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
 544         if (auth->au_flavor)
 545                 seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
 546
 547         /*
 548          * Display superblock I/O counters
 549          */
 550         for_each_possible_cpu(cpu) {
 551                 struct nfs_iostats *stats;
 552
 553                 preempt_disable();
 554                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 555
 556                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 557                         totals.events[i] += stats->events[i];
 558                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 559                         totals.bytes[i] += stats->bytes[i];
 560
 561                 preempt_enable();
 562         }
 563
 564         seq_printf(m, "\n\tevents:\t");
 565         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 566                 seq_printf(m, "%lu ", totals.events[i]);
 567         seq_printf(m, "\n\tbytes:\t");
 568         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 569                 seq_printf(m, "%Lu ", totals.bytes[i]);
 570         seq_printf(m, "\n");
 571
 572         rpc_print_iostats(m, nfss->client);
 573
 574         return 0;
 575 }
 576
 577 /*
 578  * Begin unmount by attempting to remove all automounted mountpoints we added
 579  * in response to xdev traversals and referrals
 580  */
 581 static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
 582 {
 583         struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
 584         struct rpc_clnt *rpc;
 585
 586         shrink_submounts(vfsmnt, &nfs_automount_list);
 587
 588         if (!(flags & MNT_FORCE))
 589                 return;
 590         /* -EIO all pending I/O */
 591         rpc = server->client_acl;
 592         if (!IS_ERR(rpc))
 593                 rpc_killall_tasks(rpc);
 594         rpc = server->client;
 595         if (!IS_ERR(rpc))
 596                 rpc_killall_tasks(rpc);
 597 }
 598
 599 /*
 600  * Sanity-check a server address provided by the mount command
 601  */
 602 static int nfs_verify_server_address(struct sockaddr *addr)
 603 {
 604         switch (addr->sa_family) {
 605         case AF_INET: {
 606                 struct sockaddr_in *sa = (struct sockaddr_in *) addr;
 607                 if (sa->sin_addr.s_addr != INADDR_ANY)
 608                         return 1;
 609                 break;
 610         }
 611         }
 612
 613         return 0;
 614 }
 615
 616 /*
 617  * Error-check and convert a string of mount options from user space into
 618  * a data structure
 619  */
 620 static int nfs_parse_mount_options(char *raw,
 621                                    struct nfs_parsed_mount_data *mnt)
 622 {
 623         char *p, *string;
 624
 625         if (!raw) {
 626                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 627                 return 1;
 628         }
 629         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 630
 631         while ((p = strsep(&raw, ",")) != NULL) {
 632                 substring_t args[MAX_OPT_ARGS];
 633                 int option, token;
 634
 635                 if (!*p)
 636                         continue;
 637
 638                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
 639
 640                 token = match_token(p, nfs_mount_option_tokens, args);
 641                 switch (token) {
 642                 case Opt_soft:
 643                         mnt->flags |= NFS_MOUNT_SOFT;
 644                         break;
 645                 case Opt_hard:
 646                         mnt->flags &= ~NFS_MOUNT_SOFT;
 647                         break;
 648                 case Opt_intr:
 649                         mnt->flags |= NFS_MOUNT_INTR;
 650                         break;
 651                 case Opt_nointr:
 652                         mnt->flags &= ~NFS_MOUNT_INTR;
 653                         break;
 654                 case Opt_posix:
 655                         mnt->flags |= NFS_MOUNT_POSIX;
 656                         break;
 657                 case Opt_noposix:
 658                         mnt->flags &= ~NFS_MOUNT_POSIX;
 659                         break;
 660                 case Opt_cto:
 661                         mnt->flags &= ~NFS_MOUNT_NOCTO;
 662                         break;
 663                 case Opt_nocto:
 664                         mnt->flags |= NFS_MOUNT_NOCTO;
 665                         break;
 666                 case Opt_ac:
 667                         mnt->flags &= ~NFS_MOUNT_NOAC;
 668                         break;
 669                 case Opt_noac:
 670                         mnt->flags |= NFS_MOUNT_NOAC;
 671                         break;
 672                 case Opt_lock:
 673                         mnt->flags &= ~NFS_MOUNT_NONLM;
 674                         break;
 675                 case Opt_nolock:
 676                         mnt->flags |= NFS_MOUNT_NONLM;
 677                         break;
 678                 case Opt_v2:
 679                         mnt->flags &= ~NFS_MOUNT_VER3;
 680                         break;
 681                 case Opt_v3:
 682                         mnt->flags |= NFS_MOUNT_VER3;
 683                         break;
 684                 case Opt_udp:
 685                         mnt->flags &= ~NFS_MOUNT_TCP;
 686                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 687                         mnt->timeo = 7;
 688                         mnt->retrans = 5;
 689                         break;
 690                 case Opt_tcp:
 691                         mnt->flags |= NFS_MOUNT_TCP;
 692                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 693                         mnt->timeo = 600;
 694                         mnt->retrans = 2;
 695                         break;
 696                 case Opt_rdma:
 697                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
 698                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
 699                         mnt->timeo = 600;
 700                         mnt->retrans = 2;
 701                         break;
 702                 case Opt_acl:
 703                         mnt->flags &= ~NFS_MOUNT_NOACL;
 704                         break;
 705                 case Opt_noacl:
 706                         mnt->flags |= NFS_MOUNT_NOACL;
 707                         break;
 708                 case Opt_rdirplus:
 709                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
 710                         break;
 711                 case Opt_nordirplus:
 712                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
 713                         break;
 714                 case Opt_sharecache:
 715                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
 716                         break;
 717                 case Opt_nosharecache:
 718                         mnt->flags |= NFS_MOUNT_UNSHARED;
 719                         break;
 720
 721                 case Opt_port:
 722                         if (match_int(args, &option))
 723                                 return 0;
 724                         if (option < 0 || option > 65535)
 725                                 return 0;
 726                         mnt->nfs_server.address.sin_port = htons(option);
 727                         break;
 728                 case Opt_rsize:
 729                         if (match_int(args, &mnt->rsize))
 730                                 return 0;
 731                         break;
 732                 case Opt_wsize:
 733                         if (match_int(args, &mnt->wsize))
 734                                 return 0;
 735                         break;
 736                 case Opt_bsize:
 737                         if (match_int(args, &option))
 738                                 return 0;
 739                         if (option < 0)
 740                                 return 0;
 741                         mnt->bsize = option;
 742                         break;
 743                 case Opt_timeo:
 744                         if (match_int(args, &mnt->timeo))
 745                                 return 0;
 746                         break;
 747                 case Opt_retrans:
 748                         if (match_int(args, &mnt->retrans))
 749                                 return 0;
 750                         break;
 751                 case Opt_acregmin:
 752                         if (match_int(args, &mnt->acregmin))
 753                                 return 0;
 754                         break;
 755                 case Opt_acregmax:
 756                         if (match_int(args, &mnt->acregmax))
 757                                 return 0;
 758                         break;
 759                 case Opt_acdirmin:
 760                         if (match_int(args, &mnt->acdirmin))
 761                                 return 0;
 762                         break;
 763                 case Opt_acdirmax:
 764                         if (match_int(args, &mnt->acdirmax))
 765                                 return 0;
 766                         break;
 767                 case Opt_actimeo:
 768                         if (match_int(args, &option))
 769                                 return 0;
 770                         if (option < 0)
 771                                 return 0;
 772                         mnt->acregmin =
 773                         mnt->acregmax =
 774                         mnt->acdirmin =
 775                         mnt->acdirmax = option;
 776                         break;
 777                 case Opt_namelen:
 778                         if (match_int(args, &mnt->namlen))
 779                                 return 0;
 780                         break;
 781                 case Opt_mountport:
 782                         if (match_int(args, &option))
 783                                 return 0;
 784                         if (option < 0 || option > 65535)
 785                                 return 0;
 786                         mnt->mount_server.port = option;
 787                         break;
 788                 case Opt_mountvers:
 789                         if (match_int(args, &option))
 790                                 return 0;
 791                         if (option < 0)
 792                                 return 0;
 793                         mnt->mount_server.version = option;
 794                         break;
 795                 case Opt_nfsvers:
 796                         if (match_int(args, &option))
 797                                 return 0;
 798                         switch (option) {
 799                         case 2:
 800                                 mnt->flags &= ~NFS_MOUNT_VER3;
 801                                 break;
 802                         case 3:
 803                                 mnt->flags |= NFS_MOUNT_VER3;
 804                                 break;
 805                         default:
 806                                 goto out_unrec_vers;
 807                         }
 808                         break;
 809
 810                 case Opt_sec:
 811                         string = match_strdup(args);
 812                         if (string == NULL)
 813                                 goto out_nomem;
 814                         token = match_token(string, nfs_secflavor_tokens, args);
 815                         kfree(string);
 816
 817                         /*
 818                          * The flags setting is for v2/v3.  The flavor_len
 819                          * setting is for v4.  v2/v3 also need to know the
 820                          * difference between NULL and UNIX.
 821                          */
 822                         switch (token) {
 823                         case Opt_sec_none:
 824                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 825                                 mnt->auth_flavor_len = 0;
 826                                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 827                                 break;
 828                         case Opt_sec_sys:
 829                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 830                                 mnt->auth_flavor_len = 0;
 831                                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 832                                 break;
 833                         case Opt_sec_krb5:
 834                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 835                                 mnt->auth_flavor_len = 1;
 836                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 837                                 break;
 838                         case Opt_sec_krb5i:
 839                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 840                                 mnt->auth_flavor_len = 1;
 841                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 842                                 break;
 843                         case Opt_sec_krb5p:
 844                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 845                                 mnt->auth_flavor_len = 1;
 846                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 847                                 break;
 848                         case Opt_sec_lkey:
 849                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 850                                 mnt->auth_flavor_len = 1;
 851                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 852                                 break;
 853                         case Opt_sec_lkeyi:
 854                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 855                                 mnt->auth_flavor_len = 1;
 856                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 857                                 break;
 858                         case Opt_sec_lkeyp:
 859                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 860                                 mnt->auth_flavor_len = 1;
 861                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 862                                 break;
 863                         case Opt_sec_spkm:
 864                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 865                                 mnt->auth_flavor_len = 1;
 866                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 867                                 break;
 868                         case Opt_sec_spkmi:
 869                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 870                                 mnt->auth_flavor_len = 1;
 871                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 872                                 break;
 873                         case Opt_sec_spkmp:
 874                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 875                                 mnt->auth_flavor_len = 1;
 876                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 877                                 break;
 878                         default:
 879                                 goto out_unrec_sec;
 880                         }
 881                         break;
 882                 case Opt_proto:
 883                         string = match_strdup(args);
 884                         if (string == NULL)
 885                                 goto out_nomem;
 886                         token = match_token(string,
 887                                             nfs_xprt_protocol_tokens, args);
 888                         kfree(string);
 889
 890                         switch (token) {
 891                         case Opt_xprt_udp:
 892                                 mnt->flags &= ~NFS_MOUNT_TCP;
 893                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 894                                 mnt->timeo = 7;
 895                                 mnt->retrans = 5;
 896                                 break;
 897                         case Opt_xprt_tcp:
 898                                 mnt->flags |= NFS_MOUNT_TCP;
 899                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 900                                 mnt->timeo = 600;
 901                                 mnt->retrans = 2;
 902                                 break;
 903                         case Opt_xprt_rdma:
 904                                 /* vector side protocols to TCP */
 905                                 mnt->flags |= NFS_MOUNT_TCP;
 906                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
 907                                 mnt->timeo = 600;
 908                                 mnt->retrans = 2;
 909                                 break;
 910                         default:
 911                                 goto out_unrec_xprt;
 912                         }
 913                         break;
 914                 case Opt_mountproto:
 915                         string = match_strdup(args);
 916                         if (string == NULL)
 917                                 goto out_nomem;
 918                         token = match_token(string,
 919                                             nfs_xprt_protocol_tokens, args);
 920                         kfree(string);
 921
 922                         switch (token) {
 923                         case Opt_xprt_udp:
 924                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 925                                 break;
 926                         case Opt_xprt_tcp:
 927                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 928                                 break;
 929                         case Opt_xprt_rdma: /* not used for side protocols */
 930                         default:
 931                                 goto out_unrec_xprt;
 932                         }
 933                         break;
 934                 case Opt_addr:
 935                         string = match_strdup(args);
 936                         if (string == NULL)
 937                                 goto out_nomem;
 938                         mnt->nfs_server.address.sin_family = AF_INET;
 939                         mnt->nfs_server.address.sin_addr.s_addr =
 940                                                         in_aton(string);
 941                         kfree(string);
 942                         break;
 943                 case Opt_clientaddr:
 944                         string = match_strdup(args);
 945                         if (string == NULL)
 946                                 goto out_nomem;
 947                         mnt->client_address = string;
 948                         break;
 949                 case Opt_mountaddr:
 950                         string = match_strdup(args);
 951                         if (string == NULL)
 952                                 goto out_nomem;
 953                         mnt->mount_server.address.sin_family = AF_INET;
 954                         mnt->mount_server.address.sin_addr.s_addr =
 955                                                         in_aton(string);
 956                         kfree(string);
 957                         break;
 958
 959                 case Opt_userspace:
 960                 case Opt_deprecated:
 961                         break;
 962
 963                 default:
 964                         goto out_unknown;
 965                 }
 966         }
 967
 968         return 1;
 969
 970 out_nomem:
 971         printk(KERN_INFO "NFS: not enough memory to parse option\n");
 972         return 0;
 973
 974 out_unrec_vers:
 975         printk(KERN_INFO "NFS: unrecognized NFS version number\n");
 976         return 0;
 977
 978 out_unrec_xprt:
 979         printk(KERN_INFO "NFS: unrecognized transport protocol\n");
 980         return 0;
 981
 982 out_unrec_sec:
 983         printk(KERN_INFO "NFS: unrecognized security flavor\n");
 984         return 0;
 985
 986 out_unknown:
 987         printk(KERN_INFO "NFS: unknown mount option: %s\n", p);
 988         return 0;
 989 }
 990
 991 /*
 992  * Use the remote server's MOUNT service to request the NFS file handle
 993  * corresponding to the provided path.
 994  */
 995 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
 996                          struct nfs_fh *root_fh)
 997 {
 998         struct sockaddr_in sin;
 999         int status;
1000
1001         if (args->mount_server.version == 0) {
1002                 if (args->flags & NFS_MOUNT_VER3)
1003                         args->mount_server.version = NFS_MNT3_VERSION;
1004                 else
1005                         args->mount_server.version = NFS_MNT_VERSION;
1006         }
1007
1008         /*
1009          * Construct the mount server's address.
1010          */
1011         if (args->mount_server.address.sin_addr.s_addr != INADDR_ANY)
1012                 sin = args->mount_server.address;
1013         else
1014                 sin = args->nfs_server.address;
1015         /*
1016          * autobind will be used if mount_server.port == 0
1017          */
1018         sin.sin_port = htons(args->mount_server.port);
1019
1020         /*
1021          * Now ask the mount server to map our export path
1022          * to a file handle.
1023          */
1024         status = nfs_mount((struct sockaddr *) &sin,
1025                            sizeof(sin),
1026                            args->nfs_server.hostname,
1027                            args->nfs_server.export_path,
1028                            args->mount_server.version,
1029                            args->mount_server.protocol,
1030                            root_fh);
1031         if (status == 0)
1032                 return 0;
1033
1034         dfprintk(MOUNT, "NFS: unable to mount server " NIPQUAD_FMT
1035                         ", error %d\n", NIPQUAD(sin.sin_addr.s_addr), status);
1036         return status;
1037 }
1038
1039 /*
1040  * Validate the NFS2/NFS3 mount data
1041  * - fills in the mount root filehandle
1042  *
1043  * For option strings, user space handles the following behaviors:
1044  *
1045  * + DNS: mapping server host name to IP address ("addr=" option)
1046  *
1047  * + failure mode: how to behave if a mount request can't be handled
1048  *   immediately ("fg/bg" option)
1049  *
1050  * + retry: how often to retry a mount request ("retry=" option)
1051  *
1052  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1053  *   mountproto=tcp after mountproto=udp, and so on
1054  */
1055 static int nfs_validate_mount_data(void *options,
1056                                    struct nfs_parsed_mount_data *args,
1057                                    struct nfs_fh *mntfh,
1058                                    const char *dev_name)
1059 {
1060         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1061
1062         memset(args, 0, sizeof(*args));
1063
1064         if (data == NULL)
1065                 goto out_no_data;
1066
1067         args->flags             = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1068         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1069         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1070         args->timeo             = 600;
1071         args->retrans           = 2;
1072         args->acregmin          = 3;
1073         args->acregmax          = 60;
1074         args->acdirmin          = 30;
1075         args->acdirmax          = 60;
1076         args->mount_server.protocol = XPRT_TRANSPORT_UDP;
1077         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1078
1079         switch (data->version) {
1080         case 1:
1081                 data->namlen = 0;
1082         case 2:
1083                 data->bsize = 0;
1084         case 3:
1085                 if (data->flags & NFS_MOUNT_VER3)
1086                         goto out_no_v3;
1087                 data->root.size = NFS2_FHSIZE;
1088                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1089         case 4:
1090                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1091                         goto out_no_sec;
1092         case 5:
1093                 memset(data->context, 0, sizeof(data->context));
1094         case 6:
1095                 if (data->flags & NFS_MOUNT_VER3)
1096                         mntfh->size = data->root.size;
1097                 else
1098                         mntfh->size = NFS2_FHSIZE;
1099
1100                 if (mntfh->size > sizeof(mntfh->data))
1101                         goto out_invalid_fh;
1102
1103                 memcpy(mntfh->data, data->root.data, mntfh->size);
1104                 if (mntfh->size < sizeof(mntfh->data))
1105                         memset(mntfh->data + mntfh->size, 0,
1106                                sizeof(mntfh->data) - mntfh->size);
1107
1108                 if (!nfs_verify_server_address((struct sockaddr *) &data->addr))
1109                         goto out_no_address;
1110
1111                 /*
1112                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1113                  * can deal with.
1114                  */
1115                 args->flags             = data->flags;
1116                 args->rsize             = data->rsize;
1117                 args->wsize             = data->wsize;
1118                 args->flags             = data->flags;
1119                 args->timeo             = data->timeo;
1120                 args->retrans           = data->retrans;
1121                 args->acregmin          = data->acregmin;
1122                 args->acregmax          = data->acregmax;
1123                 args->acdirmin          = data->acdirmin;
1124                 args->acdirmax          = data->acdirmax;
1125                 args->nfs_server.address = data->addr;
1126                 if (!(data->flags & NFS_MOUNT_TCP))
1127                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1128                 /* N.B. caller will free nfs_server.hostname in all cases */
1129                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1130                 args->namlen            = data->namlen;
1131                 args->bsize             = data->bsize;
1132                 args->auth_flavors[0]   = data->pseudoflavor;
1133                 break;
1134         default: {
1135                 unsigned int len;
1136                 char *c;
1137                 int status;
1138
1139                 if (nfs_parse_mount_options((char *)options, args) == 0)
1140                         return -EINVAL;
1141
1142                 if (!nfs_verify_server_address((struct sockaddr *)
1143                                                 &args->nfs_server.address))
1144                         goto out_no_address;
1145
1146                 c = strchr(dev_name, ':');
1147                 if (c == NULL)
1148                         return -EINVAL;
1149                 len = c - dev_name;
1150                 /* N.B. caller will free nfs_server.hostname in all cases */
1151                 args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
1152
1153                 c++;
1154                 if (strlen(c) > NFS_MAXPATHLEN)
1155                         return -ENAMETOOLONG;
1156                 args->nfs_server.export_path = c;
1157
1158                 status = nfs_try_mount(args, mntfh);
1159                 if (status)
1160                         return status;
1161
1162                 break;
1163                 }
1164         }
1165
1166         if (!(args->flags & NFS_MOUNT_SECFLAVOUR))
1167                 args->auth_flavors[0] = RPC_AUTH_UNIX;
1168
1169 #ifndef CONFIG_NFS_V3
1170         if (args->flags & NFS_MOUNT_VER3)
1171                 goto out_v3_not_compiled;
1172 #endif /* !CONFIG_NFS_V3 */
1173
1174         return 0;
1175
1176 out_no_data:
1177         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1178         return -EINVAL;
1179
1180 out_no_v3:
1181         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1182                  data->version);
1183         return -EINVAL;
1184
1185 out_no_sec:
1186         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1187         return -EINVAL;
1188
1189 #ifndef CONFIG_NFS_V3
1190 out_v3_not_compiled:
1191         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1192         return -EPROTONOSUPPORT;
1193 #endif /* !CONFIG_NFS_V3 */
1194
1195 out_no_address:
1196         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1197         return -EINVAL;
1198
1199 out_invalid_fh:
1200         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1201         return -EINVAL;
1202 }
1203
1204 /*
1205  * Initialise the common bits of the superblock
1206  */
1207 static inline void nfs_initialise_sb(struct super_block *sb)
1208 {
1209         struct nfs_server *server = NFS_SB(sb);
1210
1211         sb->s_magic = NFS_SUPER_MAGIC;
1212
1213         /* We probably want something more informative here */
1214         snprintf(sb->s_id, sizeof(sb->s_id),
1215                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1216
1217         if (sb->s_blocksize == 0)
1218                 sb->s_blocksize = nfs_block_bits(server->wsize,
1219                                                  &sb->s_blocksize_bits);
1220
1221         if (server->flags & NFS_MOUNT_NOAC)
1222                 sb->s_flags |= MS_SYNCHRONOUS;
1223
1224         nfs_super_set_maxbytes(sb, server->maxfilesize);
1225 }
1226
1227 /*
1228  * Finish setting up an NFS2/3 superblock
1229  */
1230 static void nfs_fill_super(struct super_block *sb,
1231                            struct nfs_parsed_mount_data *data)
1232 {
1233         struct nfs_server *server = NFS_SB(sb);
1234
1235         sb->s_blocksize_bits = 0;
1236         sb->s_blocksize = 0;
1237         if (data->bsize)
1238                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1239
1240         if (server->flags & NFS_MOUNT_VER3) {
1241                 /* The VFS shouldn't apply the umask to mode bits. We will do
1242                  * so ourselves when necessary.
1243                  */
1244                 sb->s_flags |= MS_POSIXACL;
1245                 sb->s_time_gran = 1;
1246         }
1247
1248         sb->s_op = &nfs_sops;
1249         nfs_initialise_sb(sb);
1250 }
1251
1252 /*
1253  * Finish setting up a cloned NFS2/3 superblock
1254  */
1255 static void nfs_clone_super(struct super_block *sb,
1256                             const struct super_block *old_sb)
1257 {
1258         struct nfs_server *server = NFS_SB(sb);
1259
1260         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1261         sb->s_blocksize = old_sb->s_blocksize;
1262         sb->s_maxbytes = old_sb->s_maxbytes;
1263
1264         if (server->flags & NFS_MOUNT_VER3) {
1265                 /* The VFS shouldn't apply the umask to mode bits. We will do
1266                  * so ourselves when necessary.
1267                  */
1268                 sb->s_flags |= MS_POSIXACL;
1269                 sb->s_time_gran = 1;
1270         }
1271
1272         sb->s_op = old_sb->s_op;
1273         nfs_initialise_sb(sb);
1274 }
1275
1276 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1277
1278 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1279 {
1280         const struct nfs_server *a = s->s_fs_info;
1281         const struct rpc_clnt *clnt_a = a->client;
1282         const struct rpc_clnt *clnt_b = b->client;
1283
1284         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1285                 goto Ebusy;
1286         if (a->nfs_client != b->nfs_client)
1287                 goto Ebusy;
1288         if (a->flags != b->flags)
1289                 goto Ebusy;
1290         if (a->wsize != b->wsize)
1291                 goto Ebusy;
1292         if (a->rsize != b->rsize)
1293                 goto Ebusy;
1294         if (a->acregmin != b->acregmin)
1295                 goto Ebusy;
1296         if (a->acregmax != b->acregmax)
1297                 goto Ebusy;
1298         if (a->acdirmin != b->acdirmin)
1299                 goto Ebusy;
1300         if (a->acdirmax != b->acdirmax)
1301                 goto Ebusy;
1302         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1303                 goto Ebusy;
1304         return 1;
1305 Ebusy:
1306         return 0;
1307 }
1308
1309 struct nfs_sb_mountdata {
1310         struct nfs_server *server;
1311         int mntflags;
1312 };
1313
1314 static int nfs_set_super(struct super_block *s, void *data)
1315 {
1316         struct nfs_sb_mountdata *sb_mntdata = data;
1317         struct nfs_server *server = sb_mntdata->server;
1318         int ret;
1319
1320         s->s_flags = sb_mntdata->mntflags;
1321         s->s_fs_info = server;
1322         ret = set_anon_super(s, server);
1323         if (ret == 0)
1324                 server->s_dev = s->s_dev;
1325         return ret;
1326 }
1327
1328 static int nfs_compare_super(struct super_block *sb, void *data)
1329 {
1330         struct nfs_sb_mountdata *sb_mntdata = data;
1331         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1332         int mntflags = sb_mntdata->mntflags;
1333
1334         if (memcmp(&old->nfs_client->cl_addr,
1335                                 &server->nfs_client->cl_addr,
1336                                 sizeof(old->nfs_client->cl_addr)) != 0)
1337                 return 0;
1338         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1339         if (old->flags & NFS_MOUNT_UNSHARED)
1340                 return 0;
1341         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1342                 return 0;
1343         return nfs_compare_mount_options(sb, server, mntflags);
1344 }
1345
1346 static int nfs_get_sb(struct file_system_type *fs_type,
1347         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1348 {
1349         struct nfs_server *server = NULL;
1350         struct super_block *s;
1351         struct nfs_fh mntfh;
1352         struct nfs_parsed_mount_data data;
1353         struct dentry *mntroot;
1354         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1355         struct nfs_sb_mountdata sb_mntdata = {
1356                 .mntflags = flags,
1357         };
1358         int error;
1359
1360         /* Validate the mount data */
1361         error = nfs_validate_mount_data(raw_data, &data, &mntfh, dev_name);
1362         if (error < 0)
1363                 goto out;
1364
1365         /* Get a volume representation */
1366         server = nfs_create_server(&data, &mntfh);
1367         if (IS_ERR(server)) {
1368                 error = PTR_ERR(server);
1369                 goto out;
1370         }
1371         sb_mntdata.server = server;
1372
1373         if (server->flags & NFS_MOUNT_UNSHARED)
1374                 compare_super = NULL;
1375
1376         /* Get a superblock - note that we may end up sharing one that already exists */
1377         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1378         if (IS_ERR(s)) {
1379                 error = PTR_ERR(s);
1380                 goto out_err_nosb;
1381         }
1382
1383         if (s->s_fs_info != server) {
1384                 nfs_free_server(server);
1385                 server = NULL;
1386         }
1387
1388         if (!s->s_root) {
1389                 /* initial superblock/root creation */
1390                 nfs_fill_super(s, &data);
1391         }
1392
1393         mntroot = nfs_get_root(s, &mntfh);
1394         if (IS_ERR(mntroot)) {
1395                 error = PTR_ERR(mntroot);
1396                 goto error_splat_super;
1397         }
1398
1399         s->s_flags |= MS_ACTIVE;
1400         mnt->mnt_sb = s;
1401         mnt->mnt_root = mntroot;
1402         error = 0;
1403
1404 out:
1405         kfree(data.nfs_server.hostname);
1406         return error;
1407
1408 out_err_nosb:
1409         nfs_free_server(server);
1410         goto out;
1411
1412 error_splat_super:
1413         up_write(&s->s_umount);
1414         deactivate_super(s);
1415         goto out;
1416 }
1417
1418 /*
1419  * Destroy an NFS2/3 superblock
1420  */
1421 static void nfs_kill_super(struct super_block *s)
1422 {
1423         struct nfs_server *server = NFS_SB(s);
1424
1425         kill_anon_super(s);
1426         nfs_free_server(server);
1427 }
1428
1429 /*
1430  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
1431  */
1432 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
1433                            const char *dev_name, void *raw_data,
1434                            struct vfsmount *mnt)
1435 {
1436         struct nfs_clone_mount *data = raw_data;
1437         struct super_block *s;
1438         struct nfs_server *server;
1439         struct dentry *mntroot;
1440         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1441         struct nfs_sb_mountdata sb_mntdata = {
1442                 .mntflags = flags,
1443         };
1444         int error;
1445
1446         dprintk("--> nfs_xdev_get_sb()\n");
1447
1448         /* create a new volume representation */
1449         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1450         if (IS_ERR(server)) {
1451                 error = PTR_ERR(server);
1452                 goto out_err_noserver;
1453         }
1454         sb_mntdata.server = server;
1455
1456         if (server->flags & NFS_MOUNT_UNSHARED)
1457                 compare_super = NULL;
1458
1459         /* Get a superblock - note that we may end up sharing one that already exists */
1460         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1461         if (IS_ERR(s)) {
1462                 error = PTR_ERR(s);
1463                 goto out_err_nosb;
1464         }
1465
1466         if (s->s_fs_info != server) {
1467                 nfs_free_server(server);
1468                 server = NULL;
1469         }
1470
1471         if (!s->s_root) {
1472                 /* initial superblock/root creation */
1473                 nfs_clone_super(s, data->sb);
1474         }
1475
1476         mntroot = nfs_get_root(s, data->fh);
1477         if (IS_ERR(mntroot)) {
1478                 error = PTR_ERR(mntroot);
1479                 goto error_splat_super;
1480         }
1481         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
1482                 dput(mntroot);
1483                 error = -ESTALE;
1484                 goto error_splat_super;
1485         }
1486
1487         s->s_flags |= MS_ACTIVE;
1488         mnt->mnt_sb = s;
1489         mnt->mnt_root = mntroot;
1490
1491         dprintk("<-- nfs_xdev_get_sb() = 0\n");
1492         return 0;
1493
1494 out_err_nosb:
1495         nfs_free_server(server);
1496 out_err_noserver:
1497         dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
1498         return error;
1499
1500 error_splat_super:
1501         up_write(&s->s_umount);
1502         deactivate_super(s);
1503         dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
1504         return error;
1505 }
1506
1507 #ifdef CONFIG_NFS_V4
1508
1509 /*
1510  * Finish setting up a cloned NFS4 superblock
1511  */
1512 static void nfs4_clone_super(struct super_block *sb,
1513                             const struct super_block *old_sb)
1514 {
1515         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1516         sb->s_blocksize = old_sb->s_blocksize;
1517         sb->s_maxbytes = old_sb->s_maxbytes;
1518         sb->s_time_gran = 1;
1519         sb->s_op = old_sb->s_op;
1520         nfs_initialise_sb(sb);
1521 }
1522
1523 /*
1524  * Set up an NFS4 superblock
1525  */
1526 static void nfs4_fill_super(struct super_block *sb)
1527 {
1528         sb->s_time_gran = 1;
1529         sb->s_op = &nfs4_sops;
1530         nfs_initialise_sb(sb);
1531 }
1532
1533 /*
1534  * Validate NFSv4 mount options
1535  */
1536 static int nfs4_validate_mount_data(void *options,
1537                                     struct nfs_parsed_mount_data *args,
1538                                     const char *dev_name)
1539 {
1540         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
1541         char *c;
1542
1543         memset(args, 0, sizeof(*args));
1544
1545         if (data == NULL)
1546                 goto out_no_data;
1547
1548         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1549         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1550         args->timeo             = 600;
1551         args->retrans           = 2;
1552         args->acregmin          = 3;
1553         args->acregmax          = 60;
1554         args->acdirmin          = 30;
1555         args->acdirmax          = 60;
1556         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1557
1558         switch (data->version) {
1559         case 1:
1560                 if (data->host_addrlen != sizeof(args->nfs_server.address))
1561                         goto out_no_address;
1562                 if (copy_from_user(&args->nfs_server.address,
1563                                    data->host_addr,
1564                                    sizeof(args->nfs_server.address)))
1565                         return -EFAULT;
1566                 if (args->nfs_server.address.sin_port == 0)
1567                         args->nfs_server.address.sin_port = htons(NFS_PORT);
1568                 if (!nfs_verify_server_address((struct sockaddr *)
1569                                                 &args->nfs_server.address))
1570                         goto out_no_address;
1571
1572                 switch (data->auth_flavourlen) {
1573                 case 0:
1574                         args->auth_flavors[0] = RPC_AUTH_UNIX;
1575                         break;
1576                 case 1:
1577                         if (copy_from_user(&args->auth_flavors[0],
1578                                            data->auth_flavours,
1579                                            sizeof(args->auth_flavors[0])))
1580                                 return -EFAULT;
1581                         break;
1582                 default:
1583                         goto out_inval_auth;
1584                 }
1585
1586                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
1587                 if (IS_ERR(c))
1588                         return PTR_ERR(c);
1589                 args->nfs_server.hostname = c;
1590
1591                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
1592                 if (IS_ERR(c))
1593                         return PTR_ERR(c);
1594                 args->nfs_server.export_path = c;
1595                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
1596
1597                 c = strndup_user(data->client_addr.data, 16);
1598                 if (IS_ERR(c))
1599                         return PTR_ERR(c);
1600                 args->client_address = c;
1601
1602                 /*
1603                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
1604                  * can deal with.
1605                  */
1606
1607                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
1608                 args->rsize     = data->rsize;
1609                 args->wsize     = data->wsize;
1610                 args->timeo     = data->timeo;
1611                 args->retrans   = data->retrans;
1612                 args->acregmin  = data->acregmin;
1613                 args->acregmax  = data->acregmax;
1614                 args->acdirmin  = data->acdirmin;
1615                 args->acdirmax  = data->acdirmax;
1616                 args->nfs_server.protocol = data->proto;
1617
1618                 break;
1619         default: {
1620                 unsigned int len;
1621
1622                 if (nfs_parse_mount_options((char *)options, args) == 0)
1623                         return -EINVAL;
1624
1625                 if (args->nfs_server.address.sin_port == 0)
1626                         args->nfs_server.address.sin_port = htons(NFS_PORT);
1627                 if (!nfs_verify_server_address((struct sockaddr *)
1628                                                 &args->nfs_server.address))
1629                         return -EINVAL;
1630
1631                 switch (args->auth_flavor_len) {
1632                 case 0:
1633                         args->auth_flavors[0] = RPC_AUTH_UNIX;
1634                         break;
1635                 case 1:
1636                         break;
1637                 default:
1638                         goto out_inval_auth;
1639                 }
1640
1641                 /*
1642                  * Split "dev_name" into "hostname:mntpath".
1643                  */
1644                 c = strchr(dev_name, ':');
1645                 if (c == NULL)
1646                         return -EINVAL;
1647                 /* while calculating len, pretend ':' is '\0' */
1648                 len = c - dev_name;
1649                 if (len > NFS4_MAXNAMLEN)
1650                         return -ENAMETOOLONG;
1651                 /* N.B. caller will free nfs_server.hostname in all cases */
1652                 args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
1653
1654                 c++;                    /* step over the ':' */
1655                 len = strlen(c);
1656                 if (len > NFS4_MAXPATHLEN)
1657                         return -ENAMETOOLONG;
1658                 args->nfs_server.export_path = kstrndup(c, len, GFP_KERNEL);
1659
1660                 dprintk("NFS: MNTPATH: '%s'\n", args->nfs_server.export_path);
1661
1662                 if (args->client_address == NULL)
1663                         goto out_no_client_address;
1664
1665                 break;
1666                 }
1667         }
1668
1669         return 0;
1670
1671 out_no_data:
1672         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
1673         return -EINVAL;
1674
1675 out_inval_auth:
1676         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
1677                  data->auth_flavourlen);
1678         return -EINVAL;
1679
1680 out_no_address:
1681         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
1682         return -EINVAL;
1683
1684 out_no_client_address:
1685         dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
1686         return -EINVAL;
1687 }
1688
1689 /*
1690  * Get the superblock for an NFS4 mountpoint
1691  */
1692 static int nfs4_get_sb(struct file_system_type *fs_type,
1693         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1694 {
1695         struct nfs_parsed_mount_data data;
1696         struct super_block *s;
1697         struct nfs_server *server;
1698         struct nfs_fh mntfh;
1699         struct dentry *mntroot;
1700         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1701         struct nfs_sb_mountdata sb_mntdata = {
1702                 .mntflags = flags,
1703         };
1704         int error;
1705
1706         /* Validate the mount data */
1707         error = nfs4_validate_mount_data(raw_data, &data, dev_name);
1708         if (error < 0)
1709                 goto out;
1710
1711         /* Get a volume representation */
1712         server = nfs4_create_server(&data, &mntfh);
1713         if (IS_ERR(server)) {
1714                 error = PTR_ERR(server);
1715                 goto out;
1716         }
1717         sb_mntdata.server = server;
1718
1719         if (server->flags & NFS4_MOUNT_UNSHARED)
1720                 compare_super = NULL;
1721
1722         /* Get a superblock - note that we may end up sharing one that already exists */
1723         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1724         if (IS_ERR(s)) {
1725                 error = PTR_ERR(s);
1726                 goto out_free;
1727         }
1728
1729         if (s->s_fs_info != server) {
1730                 nfs_free_server(server);
1731                 server = NULL;
1732         }
1733
1734         if (!s->s_root) {
1735                 /* initial superblock/root creation */
1736                 nfs4_fill_super(s);
1737         }
1738
1739         mntroot = nfs4_get_root(s, &mntfh);
1740         if (IS_ERR(mntroot)) {
1741                 error = PTR_ERR(mntroot);
1742                 goto error_splat_super;
1743         }
1744
1745         s->s_flags |= MS_ACTIVE;
1746         mnt->mnt_sb = s;
1747         mnt->mnt_root = mntroot;
1748         error = 0;
1749
1750 out:
1751         kfree(data.client_address);
1752         kfree(data.nfs_server.export_path);
1753         kfree(data.nfs_server.hostname);
1754         return error;
1755
1756 out_free:
1757         nfs_free_server(server);
1758         goto out;
1759
1760 error_splat_super:
1761         up_write(&s->s_umount);
1762         deactivate_super(s);
1763         goto out;
1764 }
1765
1766 static void nfs4_kill_super(struct super_block *sb)
1767 {
1768         struct nfs_server *server = NFS_SB(sb);
1769
1770         nfs_return_all_delegations(sb);
1771         kill_anon_super(sb);
1772
1773         nfs4_renewd_prepare_shutdown(server);
1774         nfs_free_server(server);
1775 }
1776
1777 /*
1778  * Clone an NFS4 server record on xdev traversal (FSID-change)
1779  */
1780 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
1781                             const char *dev_name, void *raw_data,
1782                             struct vfsmount *mnt)
1783 {
1784         struct nfs_clone_mount *data = raw_data;
1785         struct super_block *s;
1786         struct nfs_server *server;
1787         struct dentry *mntroot;
1788         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1789         struct nfs_sb_mountdata sb_mntdata = {
1790                 .mntflags = flags,
1791         };
1792         int error;
1793
1794         dprintk("--> nfs4_xdev_get_sb()\n");
1795
1796         /* create a new volume representation */
1797         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1798         if (IS_ERR(server)) {
1799                 error = PTR_ERR(server);
1800                 goto out_err_noserver;
1801         }
1802         sb_mntdata.server = server;
1803
1804         if (server->flags & NFS4_MOUNT_UNSHARED)
1805                 compare_super = NULL;
1806
1807         /* Get a superblock - note that we may end up sharing one that already exists */
1808         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1809         if (IS_ERR(s)) {
1810                 error = PTR_ERR(s);
1811                 goto out_err_nosb;
1812         }
1813
1814         if (s->s_fs_info != server) {
1815                 nfs_free_server(server);
1816                 server = NULL;
1817         }
1818
1819         if (!s->s_root) {
1820                 /* initial superblock/root creation */
1821                 nfs4_clone_super(s, data->sb);
1822         }
1823
1824         mntroot = nfs4_get_root(s, data->fh);
1825         if (IS_ERR(mntroot)) {
1826                 error = PTR_ERR(mntroot);
1827                 goto error_splat_super;
1828         }
1829         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
1830                 dput(mntroot);
1831                 error = -ESTALE;
1832                 goto error_splat_super;
1833         }
1834
1835         s->s_flags |= MS_ACTIVE;
1836         mnt->mnt_sb = s;
1837         mnt->mnt_root = mntroot;
1838
1839         dprintk("<-- nfs4_xdev_get_sb() = 0\n");
1840         return 0;
1841
1842 out_err_nosb:
1843         nfs_free_server(server);
1844 out_err_noserver:
1845         dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
1846         return error;
1847
1848 error_splat_super:
1849         up_write(&s->s_umount);
1850         deactivate_super(s);
1851         dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
1852         return error;
1853 }
1854
1855 /*
1856  * Create an NFS4 server record on referral traversal
1857  */
1858 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
1859                                 const char *dev_name, void *raw_data,
1860                                 struct vfsmount *mnt)
1861 {
1862         struct nfs_clone_mount *data = raw_data;
1863         struct super_block *s;
1864         struct nfs_server *server;
1865         struct dentry *mntroot;
1866         struct nfs_fh mntfh;
1867         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1868         struct nfs_sb_mountdata sb_mntdata = {
1869                 .mntflags = flags,
1870         };
1871         int error;
1872
1873         dprintk("--> nfs4_referral_get_sb()\n");
1874
1875         /* create a new volume representation */
1876         server = nfs4_create_referral_server(data, &mntfh);
1877         if (IS_ERR(server)) {
1878                 error = PTR_ERR(server);
1879                 goto out_err_noserver;
1880         }
1881         sb_mntdata.server = server;
1882
1883         if (server->flags & NFS4_MOUNT_UNSHARED)
1884                 compare_super = NULL;
1885
1886         /* Get a superblock - note that we may end up sharing one that already exists */
1887         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1888         if (IS_ERR(s)) {
1889                 error = PTR_ERR(s);
1890                 goto out_err_nosb;
1891         }
1892
1893         if (s->s_fs_info != server) {
1894                 nfs_free_server(server);
1895                 server = NULL;
1896         }
1897
1898         if (!s->s_root) {
1899                 /* initial superblock/root creation */
1900                 nfs4_fill_super(s);
1901         }
1902
1903         mntroot = nfs4_get_root(s, &mntfh);
1904         if (IS_ERR(mntroot)) {
1905                 error = PTR_ERR(mntroot);
1906                 goto error_splat_super;
1907         }
1908         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
1909                 dput(mntroot);
1910                 error = -ESTALE;
1911                 goto error_splat_super;
1912         }
1913
1914         s->s_flags |= MS_ACTIVE;
1915         mnt->mnt_sb = s;
1916         mnt->mnt_root = mntroot;
1917
1918         dprintk("<-- nfs4_referral_get_sb() = 0\n");
1919         return 0;
1920
1921 out_err_nosb:
1922         nfs_free_server(server);
1923 out_err_noserver:
1924         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
1925         return error;
1926
1927 error_splat_super:
1928         up_write(&s->s_umount);
1929         deactivate_super(s);
1930         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
1931         return error;
1932 }
1933
1934 #endif /* CONFIG_NFS_V4 */