err.no Git - linux-2.6/blob - fs/nfs/super.c

   1 /*
   2  *  linux/fs/nfs/super.c
   3  *
   4  *  Copyright (C) 1992  Rick Sladkey
   5  *
   6  *  nfs superblock handling functions
   7  *
   8  *  Modularised by Alan Cox <Alan.Cox@linux.org>, while hacking some
   9  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
  10  *
  11  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
  12  *  J.S.Peatfield@damtp.cam.ac.uk
  13  *
  14  *  Split from inode.c by David Howells <dhowells@redhat.com>
  15  *
  16  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
  17  *   particular server are held in the same superblock
  18  * - NFS superblocks can have several effective roots to the dentry tree
  19  * - directory type roots are spliced into the tree when a path from one root reaches the root
  20  *   of another (see nfs_lookup())
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25
  26 #include <linux/time.h>
  27 #include <linux/kernel.h>
  28 #include <linux/mm.h>
  29 #include <linux/string.h>
  30 #include <linux/stat.h>
  31 #include <linux/errno.h>
  32 #include <linux/unistd.h>
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/stats.h>
  35 #include <linux/sunrpc/metrics.h>
  36 #include <linux/sunrpc/xprtsock.h>
  37 #include <linux/sunrpc/xprtrdma.h>
  38 #include <linux/nfs_fs.h>
  39 #include <linux/nfs_mount.h>
  40 #include <linux/nfs4_mount.h>
  41 #include <linux/lockd/bind.h>
  42 #include <linux/smp_lock.h>
  43 #include <linux/seq_file.h>
  44 #include <linux/mount.h>
  45 #include <linux/nfs_idmap.h>
  46 #include <linux/vfs.h>
  47 #include <linux/inet.h>
  48 #include <linux/nfs_xdr.h>
  49 #include <linux/magic.h>
  50 #include <linux/parser.h>
  51
  52 #include <asm/system.h>
  53 #include <asm/uaccess.h>
  54
  55 #include "nfs4_fs.h"
  56 #include "callback.h"
  57 #include "delegation.h"
  58 #include "iostat.h"
  59 #include "internal.h"
  60
  61 #define NFSDBG_FACILITY         NFSDBG_VFS
  62
  63 enum {
  64         /* Mount options that take no arguments */
  65         Opt_soft, Opt_hard,
  66         Opt_intr, Opt_nointr,
  67         Opt_posix, Opt_noposix,
  68         Opt_cto, Opt_nocto,
  69         Opt_ac, Opt_noac,
  70         Opt_lock, Opt_nolock,
  71         Opt_v2, Opt_v3,
  72         Opt_udp, Opt_tcp, Opt_rdma,
  73         Opt_acl, Opt_noacl,
  74         Opt_rdirplus, Opt_nordirplus,
  75         Opt_sharecache, Opt_nosharecache,
  76
  77         /* Mount options that take integer arguments */
  78         Opt_port,
  79         Opt_rsize, Opt_wsize, Opt_bsize,
  80         Opt_timeo, Opt_retrans,
  81         Opt_acregmin, Opt_acregmax,
  82         Opt_acdirmin, Opt_acdirmax,
  83         Opt_actimeo,
  84         Opt_namelen,
  85         Opt_mountport,
  86         Opt_mountprog, Opt_mountvers,
  87         Opt_nfsvers,
  88
  89         /* Mount options that take string arguments */
  90         Opt_sec, Opt_proto, Opt_mountproto,
  91         Opt_addr, Opt_mountaddr, Opt_clientaddr,
  92
  93         /* Mount options that are ignored */
  94         Opt_userspace, Opt_deprecated,
  95
  96         Opt_err
  97 };
  98
  99 static match_table_t nfs_mount_option_tokens = {
 100         { Opt_userspace, "bg" },
 101         { Opt_userspace, "fg" },
 102         { Opt_soft, "soft" },
 103         { Opt_hard, "hard" },
 104         { Opt_intr, "intr" },
 105         { Opt_nointr, "nointr" },
 106         { Opt_posix, "posix" },
 107         { Opt_noposix, "noposix" },
 108         { Opt_cto, "cto" },
 109         { Opt_nocto, "nocto" },
 110         { Opt_ac, "ac" },
 111         { Opt_noac, "noac" },
 112         { Opt_lock, "lock" },
 113         { Opt_nolock, "nolock" },
 114         { Opt_v2, "v2" },
 115         { Opt_v3, "v3" },
 116         { Opt_udp, "udp" },
 117         { Opt_tcp, "tcp" },
 118         { Opt_rdma, "rdma" },
 119         { Opt_acl, "acl" },
 120         { Opt_noacl, "noacl" },
 121         { Opt_rdirplus, "rdirplus" },
 122         { Opt_nordirplus, "nordirplus" },
 123         { Opt_sharecache, "sharecache" },
 124         { Opt_nosharecache, "nosharecache" },
 125
 126         { Opt_port, "port=%u" },
 127         { Opt_rsize, "rsize=%u" },
 128         { Opt_wsize, "wsize=%u" },
 129         { Opt_bsize, "bsize=%u" },
 130         { Opt_timeo, "timeo=%u" },
 131         { Opt_retrans, "retrans=%u" },
 132         { Opt_acregmin, "acregmin=%u" },
 133         { Opt_acregmax, "acregmax=%u" },
 134         { Opt_acdirmin, "acdirmin=%u" },
 135         { Opt_acdirmax, "acdirmax=%u" },
 136         { Opt_actimeo, "actimeo=%u" },
 137         { Opt_userspace, "retry=%u" },
 138         { Opt_namelen, "namlen=%u" },
 139         { Opt_mountport, "mountport=%u" },
 140         { Opt_mountprog, "mountprog=%u" },
 141         { Opt_mountvers, "mountvers=%u" },
 142         { Opt_nfsvers, "nfsvers=%u" },
 143         { Opt_nfsvers, "vers=%u" },
 144
 145         { Opt_sec, "sec=%s" },
 146         { Opt_proto, "proto=%s" },
 147         { Opt_mountproto, "mountproto=%s" },
 148         { Opt_addr, "addr=%s" },
 149         { Opt_clientaddr, "clientaddr=%s" },
 150         { Opt_userspace, "mounthost=%s" },
 151         { Opt_mountaddr, "mountaddr=%s" },
 152
 153         { Opt_err, NULL }
 154 };
 155
 156 enum {
 157         Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
 158
 159         Opt_xprt_err
 160 };
 161
 162 static match_table_t nfs_xprt_protocol_tokens = {
 163         { Opt_xprt_udp, "udp" },
 164         { Opt_xprt_tcp, "tcp" },
 165         { Opt_xprt_rdma, "rdma" },
 166
 167         { Opt_xprt_err, NULL }
 168 };
 169
 170 enum {
 171         Opt_sec_none, Opt_sec_sys,
 172         Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
 173         Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
 174         Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
 175
 176         Opt_sec_err
 177 };
 178
 179 static match_table_t nfs_secflavor_tokens = {
 180         { Opt_sec_none, "none" },
 181         { Opt_sec_none, "null" },
 182         { Opt_sec_sys, "sys" },
 183
 184         { Opt_sec_krb5, "krb5" },
 185         { Opt_sec_krb5i, "krb5i" },
 186         { Opt_sec_krb5p, "krb5p" },
 187
 188         { Opt_sec_lkey, "lkey" },
 189         { Opt_sec_lkeyi, "lkeyi" },
 190         { Opt_sec_lkeyp, "lkeyp" },
 191
 192         { Opt_sec_err, NULL }
 193 };
 194
 195
 196 static void nfs_umount_begin(struct vfsmount *, int);
 197 static int  nfs_statfs(struct dentry *, struct kstatfs *);
 198 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
 199 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
 200 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
 201 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
 202                 int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 203 static void nfs_kill_super(struct super_block *);
 204 static void nfs_put_super(struct super_block *);
 205
 206 static struct file_system_type nfs_fs_type = {
 207         .owner          = THIS_MODULE,
 208         .name           = "nfs",
 209         .get_sb         = nfs_get_sb,
 210         .kill_sb        = nfs_kill_super,
 211         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 212 };
 213
 214 struct file_system_type nfs_xdev_fs_type = {
 215         .owner          = THIS_MODULE,
 216         .name           = "nfs",
 217         .get_sb         = nfs_xdev_get_sb,
 218         .kill_sb        = nfs_kill_super,
 219         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 220 };
 221
 222 static const struct super_operations nfs_sops = {
 223         .alloc_inode    = nfs_alloc_inode,
 224         .destroy_inode  = nfs_destroy_inode,
 225         .write_inode    = nfs_write_inode,
 226         .put_super      = nfs_put_super,
 227         .statfs         = nfs_statfs,
 228         .clear_inode    = nfs_clear_inode,
 229         .umount_begin   = nfs_umount_begin,
 230         .show_options   = nfs_show_options,
 231         .show_stats     = nfs_show_stats,
 232 };
 233
 234 #ifdef CONFIG_NFS_V4
 235 static int nfs4_get_sb(struct file_system_type *fs_type,
 236         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 237 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
 238         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 239 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 240         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
 241 static void nfs4_kill_super(struct super_block *sb);
 242
 243 static struct file_system_type nfs4_fs_type = {
 244         .owner          = THIS_MODULE,
 245         .name           = "nfs4",
 246         .get_sb         = nfs4_get_sb,
 247         .kill_sb        = nfs4_kill_super,
 248         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 249 };
 250
 251 struct file_system_type nfs4_xdev_fs_type = {
 252         .owner          = THIS_MODULE,
 253         .name           = "nfs4",
 254         .get_sb         = nfs4_xdev_get_sb,
 255         .kill_sb        = nfs4_kill_super,
 256         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 257 };
 258
 259 struct file_system_type nfs4_referral_fs_type = {
 260         .owner          = THIS_MODULE,
 261         .name           = "nfs4",
 262         .get_sb         = nfs4_referral_get_sb,
 263         .kill_sb        = nfs4_kill_super,
 264         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 265 };
 266
 267 static const struct super_operations nfs4_sops = {
 268         .alloc_inode    = nfs_alloc_inode,
 269         .destroy_inode  = nfs_destroy_inode,
 270         .write_inode    = nfs_write_inode,
 271         .statfs         = nfs_statfs,
 272         .clear_inode    = nfs4_clear_inode,
 273         .umount_begin   = nfs_umount_begin,
 274         .show_options   = nfs_show_options,
 275         .show_stats     = nfs_show_stats,
 276 };
 277 #endif
 278
 279 static struct shrinker acl_shrinker = {
 280         .shrink         = nfs_access_cache_shrinker,
 281         .seeks          = DEFAULT_SEEKS,
 282 };
 283
 284 /*
 285  * Register the NFS filesystems
 286  */
 287 int __init register_nfs_fs(void)
 288 {
 289         int ret;
 290
 291         ret = register_filesystem(&nfs_fs_type);
 292         if (ret < 0)
 293                 goto error_0;
 294
 295         ret = nfs_register_sysctl();
 296         if (ret < 0)
 297                 goto error_1;
 298 #ifdef CONFIG_NFS_V4
 299         ret = register_filesystem(&nfs4_fs_type);
 300         if (ret < 0)
 301                 goto error_2;
 302 #endif
 303         register_shrinker(&acl_shrinker);
 304         return 0;
 305
 306 #ifdef CONFIG_NFS_V4
 307 error_2:
 308         nfs_unregister_sysctl();
 309 #endif
 310 error_1:
 311         unregister_filesystem(&nfs_fs_type);
 312 error_0:
 313         return ret;
 314 }
 315
 316 /*
 317  * Unregister the NFS filesystems
 318  */
 319 void __exit unregister_nfs_fs(void)
 320 {
 321         unregister_shrinker(&acl_shrinker);
 322 #ifdef CONFIG_NFS_V4
 323         unregister_filesystem(&nfs4_fs_type);
 324 #endif
 325         nfs_unregister_sysctl();
 326         unregister_filesystem(&nfs_fs_type);
 327 }
 328
 329 void nfs_sb_active(struct nfs_server *server)
 330 {
 331         atomic_inc(&server->active);
 332 }
 333
 334 void nfs_sb_deactive(struct nfs_server *server)
 335 {
 336         if (atomic_dec_and_test(&server->active))
 337                 wake_up(&server->active_wq);
 338 }
 339
 340 static void nfs_put_super(struct super_block *sb)
 341 {
 342         struct nfs_server *server = NFS_SB(sb);
 343         /*
 344          * Make sure there are no outstanding ops to this server.
 345          * If so, wait for them to finish before allowing the
 346          * unmount to continue.
 347          */
 348         wait_event(server->active_wq, atomic_read(&server->active) == 0);
 349 }
 350
 351 /*
 352  * Deliver file system statistics to userspace
 353  */
 354 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 355 {
 356         struct nfs_server *server = NFS_SB(dentry->d_sb);
 357         unsigned char blockbits;
 358         unsigned long blockres;
 359         struct nfs_fh *fh = NFS_FH(dentry->d_inode);
 360         struct nfs_fattr fattr;
 361         struct nfs_fsstat res = {
 362                         .fattr = &fattr,
 363         };
 364         int error;
 365
 366         lock_kernel();
 367
 368         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 369         if (error < 0)
 370                 goto out_err;
 371         buf->f_type = NFS_SUPER_MAGIC;
 372
 373         /*
 374          * Current versions of glibc do not correctly handle the
 375          * case where f_frsize != f_bsize.  Eventually we want to
 376          * report the value of wtmult in this field.
 377          */
 378         buf->f_frsize = dentry->d_sb->s_blocksize;
 379
 380         /*
 381          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 382          * are reported in units of f_frsize.  Linux hasn't had
 383          * an f_frsize field in its statfs struct until recently,
 384          * thus historically Linux's sys_statfs reports these
 385          * fields in units of f_bsize.
 386          */
 387         buf->f_bsize = dentry->d_sb->s_blocksize;
 388         blockbits = dentry->d_sb->s_blocksize_bits;
 389         blockres = (1 << blockbits) - 1;
 390         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 391         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 392         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 393
 394         buf->f_files = res.tfiles;
 395         buf->f_ffree = res.afiles;
 396
 397         buf->f_namelen = server->namelen;
 398
 399         unlock_kernel();
 400         return 0;
 401
 402  out_err:
 403         dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
 404         unlock_kernel();
 405         return error;
 406 }
 407
 408 /*
 409  * Map the security flavour number to a name
 410  */
 411 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 412 {
 413         static const struct {
 414                 rpc_authflavor_t flavour;
 415                 const char *str;
 416         } sec_flavours[] = {
 417                 { RPC_AUTH_NULL, "null" },
 418                 { RPC_AUTH_UNIX, "sys" },
 419                 { RPC_AUTH_GSS_KRB5, "krb5" },
 420                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 421                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 422                 { RPC_AUTH_GSS_LKEY, "lkey" },
 423                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 424                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 425                 { RPC_AUTH_GSS_SPKM, "spkm" },
 426                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 427                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 428                 { UINT_MAX, "unknown" }
 429         };
 430         int i;
 431
 432         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 433                 if (sec_flavours[i].flavour == flavour)
 434                         break;
 435         }
 436         return sec_flavours[i].str;
 437 }
 438
 439 /*
 440  * Describe the mount options in force on this server representation
 441  */
 442 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
 443 {
 444         static const struct proc_nfs_info {
 445                 int flag;
 446                 const char *str;
 447                 const char *nostr;
 448         } nfs_info[] = {
 449                 { NFS_MOUNT_SOFT, ",soft", ",hard" },
 450                 { NFS_MOUNT_INTR, ",intr", ",nointr" },
 451                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 452                 { NFS_MOUNT_NOAC, ",noac", "" },
 453                 { NFS_MOUNT_NONLM, ",nolock", "" },
 454                 { NFS_MOUNT_NOACL, ",noacl", "" },
 455                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 456                 { NFS_MOUNT_UNSHARED, ",nosharecache", ""},
 457                 { 0, NULL, NULL }
 458         };
 459         const struct proc_nfs_info *nfs_infop;
 460         struct nfs_client *clp = nfss->nfs_client;
 461
 462         seq_printf(m, ",vers=%d", clp->rpc_ops->version);
 463         seq_printf(m, ",rsize=%d", nfss->rsize);
 464         seq_printf(m, ",wsize=%d", nfss->wsize);
 465         if (nfss->acregmin != 3*HZ || showdefaults)
 466                 seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
 467         if (nfss->acregmax != 60*HZ || showdefaults)
 468                 seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
 469         if (nfss->acdirmin != 30*HZ || showdefaults)
 470                 seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
 471         if (nfss->acdirmax != 60*HZ || showdefaults)
 472                 seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
 473         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 474                 if (nfss->flags & nfs_infop->flag)
 475                         seq_puts(m, nfs_infop->str);
 476                 else
 477                         seq_puts(m, nfs_infop->nostr);
 478         }
 479         seq_printf(m, ",proto=%s",
 480                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
 481         seq_printf(m, ",timeo=%lu", 10U * clp->retrans_timeo / HZ);
 482         seq_printf(m, ",retrans=%u", clp->retrans_count);
 483         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 484 }
 485
 486 /*
 487  * Describe the mount options on this VFS mountpoint
 488  */
 489 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 490 {
 491         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 492
 493         nfs_show_mount_options(m, nfss, 0);
 494
 495         seq_printf(m, ",addr="NIPQUAD_FMT,
 496                 NIPQUAD(nfss->nfs_client->cl_addr.sin_addr));
 497
 498         return 0;
 499 }
 500
 501 /*
 502  * Present statistical information for this VFS mountpoint
 503  */
 504 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
 505 {
 506         int i, cpu;
 507         struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
 508         struct rpc_auth *auth = nfss->client->cl_auth;
 509         struct nfs_iostats totals = { };
 510
 511         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 512
 513         /*
 514          * Display all mount option settings
 515          */
 516         seq_printf(m, "\n\topts:\t");
 517         seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
 518         seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
 519         seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
 520         seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
 521         nfs_show_mount_options(m, nfss, 1);
 522
 523         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 524
 525         seq_printf(m, "\n\tcaps:\t");
 526         seq_printf(m, "caps=0x%x", nfss->caps);
 527         seq_printf(m, ",wtmult=%d", nfss->wtmult);
 528         seq_printf(m, ",dtsize=%d", nfss->dtsize);
 529         seq_printf(m, ",bsize=%d", nfss->bsize);
 530         seq_printf(m, ",namelen=%d", nfss->namelen);
 531
 532 #ifdef CONFIG_NFS_V4
 533         if (nfss->nfs_client->cl_nfsversion == 4) {
 534                 seq_printf(m, "\n\tnfsv4:\t");
 535                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 536                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 537                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 538         }
 539 #endif
 540
 541         /*
 542          * Display security flavor in effect for this mount
 543          */
 544         seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
 545         if (auth->au_flavor)
 546                 seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
 547
 548         /*
 549          * Display superblock I/O counters
 550          */
 551         for_each_possible_cpu(cpu) {
 552                 struct nfs_iostats *stats;
 553
 554                 preempt_disable();
 555                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 556
 557                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 558                         totals.events[i] += stats->events[i];
 559                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 560                         totals.bytes[i] += stats->bytes[i];
 561
 562                 preempt_enable();
 563         }
 564
 565         seq_printf(m, "\n\tevents:\t");
 566         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 567                 seq_printf(m, "%lu ", totals.events[i]);
 568         seq_printf(m, "\n\tbytes:\t");
 569         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 570                 seq_printf(m, "%Lu ", totals.bytes[i]);
 571         seq_printf(m, "\n");
 572
 573         rpc_print_iostats(m, nfss->client);
 574
 575         return 0;
 576 }
 577
 578 /*
 579  * Begin unmount by attempting to remove all automounted mountpoints we added
 580  * in response to xdev traversals and referrals
 581  */
 582 static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
 583 {
 584         struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
 585         struct rpc_clnt *rpc;
 586
 587         shrink_submounts(vfsmnt, &nfs_automount_list);
 588
 589         if (!(flags & MNT_FORCE))
 590                 return;
 591         /* -EIO all pending I/O */
 592         rpc = server->client_acl;
 593         if (!IS_ERR(rpc))
 594                 rpc_killall_tasks(rpc);
 595         rpc = server->client;
 596         if (!IS_ERR(rpc))
 597                 rpc_killall_tasks(rpc);
 598 }
 599
 600 /*
 601  * Sanity-check a server address provided by the mount command
 602  */
 603 static int nfs_verify_server_address(struct sockaddr *addr)
 604 {
 605         switch (addr->sa_family) {
 606         case AF_INET: {
 607                 struct sockaddr_in *sa = (struct sockaddr_in *) addr;
 608                 if (sa->sin_addr.s_addr != INADDR_ANY)
 609                         return 1;
 610                 break;
 611         }
 612         }
 613
 614         return 0;
 615 }
 616
 617 /*
 618  * Error-check and convert a string of mount options from user space into
 619  * a data structure
 620  */
 621 static int nfs_parse_mount_options(char *raw,
 622                                    struct nfs_parsed_mount_data *mnt)
 623 {
 624         char *p, *string;
 625
 626         if (!raw) {
 627                 dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
 628                 return 1;
 629         }
 630         dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
 631
 632         while ((p = strsep(&raw, ",")) != NULL) {
 633                 substring_t args[MAX_OPT_ARGS];
 634                 int option, token;
 635
 636                 if (!*p)
 637                         continue;
 638
 639                 dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
 640
 641                 token = match_token(p, nfs_mount_option_tokens, args);
 642                 switch (token) {
 643                 case Opt_soft:
 644                         mnt->flags |= NFS_MOUNT_SOFT;
 645                         break;
 646                 case Opt_hard:
 647                         mnt->flags &= ~NFS_MOUNT_SOFT;
 648                         break;
 649                 case Opt_intr:
 650                         mnt->flags |= NFS_MOUNT_INTR;
 651                         break;
 652                 case Opt_nointr:
 653                         mnt->flags &= ~NFS_MOUNT_INTR;
 654                         break;
 655                 case Opt_posix:
 656                         mnt->flags |= NFS_MOUNT_POSIX;
 657                         break;
 658                 case Opt_noposix:
 659                         mnt->flags &= ~NFS_MOUNT_POSIX;
 660                         break;
 661                 case Opt_cto:
 662                         mnt->flags &= ~NFS_MOUNT_NOCTO;
 663                         break;
 664                 case Opt_nocto:
 665                         mnt->flags |= NFS_MOUNT_NOCTO;
 666                         break;
 667                 case Opt_ac:
 668                         mnt->flags &= ~NFS_MOUNT_NOAC;
 669                         break;
 670                 case Opt_noac:
 671                         mnt->flags |= NFS_MOUNT_NOAC;
 672                         break;
 673                 case Opt_lock:
 674                         mnt->flags &= ~NFS_MOUNT_NONLM;
 675                         break;
 676                 case Opt_nolock:
 677                         mnt->flags |= NFS_MOUNT_NONLM;
 678                         break;
 679                 case Opt_v2:
 680                         mnt->flags &= ~NFS_MOUNT_VER3;
 681                         break;
 682                 case Opt_v3:
 683                         mnt->flags |= NFS_MOUNT_VER3;
 684                         break;
 685                 case Opt_udp:
 686                         mnt->flags &= ~NFS_MOUNT_TCP;
 687                         mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 688                         mnt->timeo = 7;
 689                         mnt->retrans = 5;
 690                         break;
 691                 case Opt_tcp:
 692                         mnt->flags |= NFS_MOUNT_TCP;
 693                         mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 694                         mnt->timeo = 600;
 695                         mnt->retrans = 2;
 696                         break;
 697                 case Opt_rdma:
 698                         mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
 699                         mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
 700                         mnt->timeo = 600;
 701                         mnt->retrans = 2;
 702                         break;
 703                 case Opt_acl:
 704                         mnt->flags &= ~NFS_MOUNT_NOACL;
 705                         break;
 706                 case Opt_noacl:
 707                         mnt->flags |= NFS_MOUNT_NOACL;
 708                         break;
 709                 case Opt_rdirplus:
 710                         mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
 711                         break;
 712                 case Opt_nordirplus:
 713                         mnt->flags |= NFS_MOUNT_NORDIRPLUS;
 714                         break;
 715                 case Opt_sharecache:
 716                         mnt->flags &= ~NFS_MOUNT_UNSHARED;
 717                         break;
 718                 case Opt_nosharecache:
 719                         mnt->flags |= NFS_MOUNT_UNSHARED;
 720                         break;
 721
 722                 case Opt_port:
 723                         if (match_int(args, &option))
 724                                 return 0;
 725                         if (option < 0 || option > 65535)
 726                                 return 0;
 727                         mnt->nfs_server.address.sin_port = htons(option);
 728                         break;
 729                 case Opt_rsize:
 730                         if (match_int(args, &mnt->rsize))
 731                                 return 0;
 732                         break;
 733                 case Opt_wsize:
 734                         if (match_int(args, &mnt->wsize))
 735                                 return 0;
 736                         break;
 737                 case Opt_bsize:
 738                         if (match_int(args, &option))
 739                                 return 0;
 740                         if (option < 0)
 741                                 return 0;
 742                         mnt->bsize = option;
 743                         break;
 744                 case Opt_timeo:
 745                         if (match_int(args, &mnt->timeo))
 746                                 return 0;
 747                         break;
 748                 case Opt_retrans:
 749                         if (match_int(args, &mnt->retrans))
 750                                 return 0;
 751                         break;
 752                 case Opt_acregmin:
 753                         if (match_int(args, &mnt->acregmin))
 754                                 return 0;
 755                         break;
 756                 case Opt_acregmax:
 757                         if (match_int(args, &mnt->acregmax))
 758                                 return 0;
 759                         break;
 760                 case Opt_acdirmin:
 761                         if (match_int(args, &mnt->acdirmin))
 762                                 return 0;
 763                         break;
 764                 case Opt_acdirmax:
 765                         if (match_int(args, &mnt->acdirmax))
 766                                 return 0;
 767                         break;
 768                 case Opt_actimeo:
 769                         if (match_int(args, &option))
 770                                 return 0;
 771                         if (option < 0)
 772                                 return 0;
 773                         mnt->acregmin =
 774                         mnt->acregmax =
 775                         mnt->acdirmin =
 776                         mnt->acdirmax = option;
 777                         break;
 778                 case Opt_namelen:
 779                         if (match_int(args, &mnt->namlen))
 780                                 return 0;
 781                         break;
 782                 case Opt_mountport:
 783                         if (match_int(args, &option))
 784                                 return 0;
 785                         if (option < 0 || option > 65535)
 786                                 return 0;
 787                         mnt->mount_server.port = option;
 788                         break;
 789                 case Opt_mountprog:
 790                         if (match_int(args, &option))
 791                                 return 0;
 792                         if (option < 0)
 793                                 return 0;
 794                         mnt->mount_server.program = option;
 795                         break;
 796                 case Opt_mountvers:
 797                         if (match_int(args, &option))
 798                                 return 0;
 799                         if (option < 0)
 800                                 return 0;
 801                         mnt->mount_server.version = option;
 802                         break;
 803                 case Opt_nfsvers:
 804                         if (match_int(args, &option))
 805                                 return 0;
 806                         switch (option) {
 807                         case 2:
 808                                 mnt->flags &= ~NFS_MOUNT_VER3;
 809                                 break;
 810                         case 3:
 811                                 mnt->flags |= NFS_MOUNT_VER3;
 812                                 break;
 813                         default:
 814                                 goto out_unrec_vers;
 815                         }
 816                         break;
 817
 818                 case Opt_sec:
 819                         string = match_strdup(args);
 820                         if (string == NULL)
 821                                 goto out_nomem;
 822                         token = match_token(string, nfs_secflavor_tokens, args);
 823                         kfree(string);
 824
 825                         /*
 826                          * The flags setting is for v2/v3.  The flavor_len
 827                          * setting is for v4.  v2/v3 also need to know the
 828                          * difference between NULL and UNIX.
 829                          */
 830                         switch (token) {
 831                         case Opt_sec_none:
 832                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 833                                 mnt->auth_flavor_len = 0;
 834                                 mnt->auth_flavors[0] = RPC_AUTH_NULL;
 835                                 break;
 836                         case Opt_sec_sys:
 837                                 mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
 838                                 mnt->auth_flavor_len = 0;
 839                                 mnt->auth_flavors[0] = RPC_AUTH_UNIX;
 840                                 break;
 841                         case Opt_sec_krb5:
 842                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 843                                 mnt->auth_flavor_len = 1;
 844                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
 845                                 break;
 846                         case Opt_sec_krb5i:
 847                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 848                                 mnt->auth_flavor_len = 1;
 849                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
 850                                 break;
 851                         case Opt_sec_krb5p:
 852                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 853                                 mnt->auth_flavor_len = 1;
 854                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
 855                                 break;
 856                         case Opt_sec_lkey:
 857                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 858                                 mnt->auth_flavor_len = 1;
 859                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
 860                                 break;
 861                         case Opt_sec_lkeyi:
 862                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 863                                 mnt->auth_flavor_len = 1;
 864                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
 865                                 break;
 866                         case Opt_sec_lkeyp:
 867                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 868                                 mnt->auth_flavor_len = 1;
 869                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
 870                                 break;
 871                         case Opt_sec_spkm:
 872                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 873                                 mnt->auth_flavor_len = 1;
 874                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
 875                                 break;
 876                         case Opt_sec_spkmi:
 877                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 878                                 mnt->auth_flavor_len = 1;
 879                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
 880                                 break;
 881                         case Opt_sec_spkmp:
 882                                 mnt->flags |= NFS_MOUNT_SECFLAVOUR;
 883                                 mnt->auth_flavor_len = 1;
 884                                 mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
 885                                 break;
 886                         default:
 887                                 goto out_unrec_sec;
 888                         }
 889                         break;
 890                 case Opt_proto:
 891                         string = match_strdup(args);
 892                         if (string == NULL)
 893                                 goto out_nomem;
 894                         token = match_token(string,
 895                                             nfs_xprt_protocol_tokens, args);
 896                         kfree(string);
 897
 898                         switch (token) {
 899                         case Opt_xprt_udp:
 900                                 mnt->flags &= ~NFS_MOUNT_TCP;
 901                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 902                                 mnt->timeo = 7;
 903                                 mnt->retrans = 5;
 904                                 break;
 905                         case Opt_xprt_tcp:
 906                                 mnt->flags |= NFS_MOUNT_TCP;
 907                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 908                                 mnt->timeo = 600;
 909                                 mnt->retrans = 2;
 910                                 break;
 911                         case Opt_xprt_rdma:
 912                                 /* vector side protocols to TCP */
 913                                 mnt->flags |= NFS_MOUNT_TCP;
 914                                 mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
 915                                 mnt->timeo = 600;
 916                                 mnt->retrans = 2;
 917                                 break;
 918                         default:
 919                                 goto out_unrec_xprt;
 920                         }
 921                         break;
 922                 case Opt_mountproto:
 923                         string = match_strdup(args);
 924                         if (string == NULL)
 925                                 goto out_nomem;
 926                         token = match_token(string,
 927                                             nfs_xprt_protocol_tokens, args);
 928                         kfree(string);
 929
 930                         switch (token) {
 931                         case Opt_xprt_udp:
 932                                 mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
 933                                 break;
 934                         case Opt_xprt_tcp:
 935                                 mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
 936                                 break;
 937                         case Opt_xprt_rdma: /* not used for side protocols */
 938                         default:
 939                                 goto out_unrec_xprt;
 940                         }
 941                         break;
 942                 case Opt_addr:
 943                         string = match_strdup(args);
 944                         if (string == NULL)
 945                                 goto out_nomem;
 946                         mnt->nfs_server.address.sin_family = AF_INET;
 947                         mnt->nfs_server.address.sin_addr.s_addr =
 948                                                         in_aton(string);
 949                         kfree(string);
 950                         break;
 951                 case Opt_clientaddr:
 952                         string = match_strdup(args);
 953                         if (string == NULL)
 954                                 goto out_nomem;
 955                         mnt->client_address = string;
 956                         break;
 957                 case Opt_mountaddr:
 958                         string = match_strdup(args);
 959                         if (string == NULL)
 960                                 goto out_nomem;
 961                         mnt->mount_server.address.sin_family = AF_INET;
 962                         mnt->mount_server.address.sin_addr.s_addr =
 963                                                         in_aton(string);
 964                         kfree(string);
 965                         break;
 966
 967                 case Opt_userspace:
 968                 case Opt_deprecated:
 969                         break;
 970
 971                 default:
 972                         goto out_unknown;
 973                 }
 974         }
 975
 976         return 1;
 977
 978 out_nomem:
 979         printk(KERN_INFO "NFS: not enough memory to parse option\n");
 980         return 0;
 981
 982 out_unrec_vers:
 983         printk(KERN_INFO "NFS: unrecognized NFS version number\n");
 984         return 0;
 985
 986 out_unrec_xprt:
 987         printk(KERN_INFO "NFS: unrecognized transport protocol\n");
 988         return 0;
 989
 990 out_unrec_sec:
 991         printk(KERN_INFO "NFS: unrecognized security flavor\n");
 992         return 0;
 993
 994 out_unknown:
 995         printk(KERN_INFO "NFS: unknown mount option: %s\n", p);
 996         return 0;
 997 }
 998
 999 /*
1000  * Use the remote server's MOUNT service to request the NFS file handle
1001  * corresponding to the provided path.
1002  */
1003 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1004                          struct nfs_fh *root_fh)
1005 {
1006         struct sockaddr_in sin;
1007         int status;
1008
1009         if (args->mount_server.version == 0) {
1010                 if (args->flags & NFS_MOUNT_VER3)
1011                         args->mount_server.version = NFS_MNT3_VERSION;
1012                 else
1013                         args->mount_server.version = NFS_MNT_VERSION;
1014         }
1015
1016         /*
1017          * Construct the mount server's address.
1018          */
1019         if (args->mount_server.address.sin_addr.s_addr != INADDR_ANY)
1020                 sin = args->mount_server.address;
1021         else
1022                 sin = args->nfs_server.address;
1023         /*
1024          * autobind will be used if mount_server.port == 0
1025          */
1026         sin.sin_port = htons(args->mount_server.port);
1027
1028         /*
1029          * Now ask the mount server to map our export path
1030          * to a file handle.
1031          */
1032         status = nfs_mount((struct sockaddr *) &sin,
1033                            sizeof(sin),
1034                            args->nfs_server.hostname,
1035                            args->nfs_server.export_path,
1036                            args->mount_server.version,
1037                            args->mount_server.protocol,
1038                            root_fh);
1039         if (status == 0)
1040                 return 0;
1041
1042         dfprintk(MOUNT, "NFS: unable to mount server " NIPQUAD_FMT
1043                         ", error %d\n", NIPQUAD(sin.sin_addr.s_addr), status);
1044         return status;
1045 }
1046
1047 /*
1048  * Validate the NFS2/NFS3 mount data
1049  * - fills in the mount root filehandle
1050  *
1051  * For option strings, user space handles the following behaviors:
1052  *
1053  * + DNS: mapping server host name to IP address ("addr=" option)
1054  *
1055  * + failure mode: how to behave if a mount request can't be handled
1056  *   immediately ("fg/bg" option)
1057  *
1058  * + retry: how often to retry a mount request ("retry=" option)
1059  *
1060  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1061  *   mountproto=tcp after mountproto=udp, and so on
1062  */
1063 static int nfs_validate_mount_data(void *options,
1064                                    struct nfs_parsed_mount_data *args,
1065                                    struct nfs_fh *mntfh,
1066                                    const char *dev_name)
1067 {
1068         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1069
1070         memset(args, 0, sizeof(*args));
1071
1072         if (data == NULL)
1073                 goto out_no_data;
1074
1075         args->flags             = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1076         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1077         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1078         args->timeo             = 600;
1079         args->retrans           = 2;
1080         args->acregmin          = 3;
1081         args->acregmax          = 60;
1082         args->acdirmin          = 30;
1083         args->acdirmax          = 60;
1084         args->mount_server.protocol = XPRT_TRANSPORT_UDP;
1085         args->mount_server.program = NFS_MNT_PROGRAM;
1086         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1087
1088         switch (data->version) {
1089         case 1:
1090                 data->namlen = 0;
1091         case 2:
1092                 data->bsize = 0;
1093         case 3:
1094                 if (data->flags & NFS_MOUNT_VER3)
1095                         goto out_no_v3;
1096                 data->root.size = NFS2_FHSIZE;
1097                 memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1098         case 4:
1099                 if (data->flags & NFS_MOUNT_SECFLAVOUR)
1100                         goto out_no_sec;
1101         case 5:
1102                 memset(data->context, 0, sizeof(data->context));
1103         case 6:
1104                 if (data->flags & NFS_MOUNT_VER3)
1105                         mntfh->size = data->root.size;
1106                 else
1107                         mntfh->size = NFS2_FHSIZE;
1108
1109                 if (mntfh->size > sizeof(mntfh->data))
1110                         goto out_invalid_fh;
1111
1112                 memcpy(mntfh->data, data->root.data, mntfh->size);
1113                 if (mntfh->size < sizeof(mntfh->data))
1114                         memset(mntfh->data + mntfh->size, 0,
1115                                sizeof(mntfh->data) - mntfh->size);
1116
1117                 if (!nfs_verify_server_address((struct sockaddr *) &data->addr))
1118                         goto out_no_address;
1119
1120                 /*
1121                  * Translate to nfs_parsed_mount_data, which nfs_fill_super
1122                  * can deal with.
1123                  */
1124                 args->flags             = data->flags;
1125                 args->rsize             = data->rsize;
1126                 args->wsize             = data->wsize;
1127                 args->flags             = data->flags;
1128                 args->timeo             = data->timeo;
1129                 args->retrans           = data->retrans;
1130                 args->acregmin          = data->acregmin;
1131                 args->acregmax          = data->acregmax;
1132                 args->acdirmin          = data->acdirmin;
1133                 args->acdirmax          = data->acdirmax;
1134                 args->nfs_server.address = data->addr;
1135                 if (!(data->flags & NFS_MOUNT_TCP))
1136                         args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1137                 /* N.B. caller will free nfs_server.hostname in all cases */
1138                 args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1139                 args->namlen            = data->namlen;
1140                 args->bsize             = data->bsize;
1141                 args->auth_flavors[0]   = data->pseudoflavor;
1142                 break;
1143         default: {
1144                 unsigned int len;
1145                 char *c;
1146                 int status;
1147
1148                 if (nfs_parse_mount_options((char *)options, args) == 0)
1149                         return -EINVAL;
1150
1151                 if (!nfs_verify_server_address((struct sockaddr *)
1152                                                 &args->nfs_server.address))
1153                         goto out_no_address;
1154
1155                 c = strchr(dev_name, ':');
1156                 if (c == NULL)
1157                         return -EINVAL;
1158                 len = c - dev_name;
1159                 /* N.B. caller will free nfs_server.hostname in all cases */
1160                 args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
1161
1162                 c++;
1163                 if (strlen(c) > NFS_MAXPATHLEN)
1164                         return -ENAMETOOLONG;
1165                 args->nfs_server.export_path = c;
1166
1167                 status = nfs_try_mount(args, mntfh);
1168                 if (status)
1169                         return status;
1170
1171                 break;
1172                 }
1173         }
1174
1175         if (!(args->flags & NFS_MOUNT_SECFLAVOUR))
1176                 args->auth_flavors[0] = RPC_AUTH_UNIX;
1177
1178 #ifndef CONFIG_NFS_V3
1179         if (args->flags & NFS_MOUNT_VER3)
1180                 goto out_v3_not_compiled;
1181 #endif /* !CONFIG_NFS_V3 */
1182
1183         return 0;
1184
1185 out_no_data:
1186         dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1187         return -EINVAL;
1188
1189 out_no_v3:
1190         dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1191                  data->version);
1192         return -EINVAL;
1193
1194 out_no_sec:
1195         dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1196         return -EINVAL;
1197
1198 #ifndef CONFIG_NFS_V3
1199 out_v3_not_compiled:
1200         dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1201         return -EPROTONOSUPPORT;
1202 #endif /* !CONFIG_NFS_V3 */
1203
1204 out_no_address:
1205         dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1206         return -EINVAL;
1207
1208 out_invalid_fh:
1209         dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1210         return -EINVAL;
1211 }
1212
1213 /*
1214  * Initialise the common bits of the superblock
1215  */
1216 static inline void nfs_initialise_sb(struct super_block *sb)
1217 {
1218         struct nfs_server *server = NFS_SB(sb);
1219
1220         sb->s_magic = NFS_SUPER_MAGIC;
1221
1222         /* We probably want something more informative here */
1223         snprintf(sb->s_id, sizeof(sb->s_id),
1224                  "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1225
1226         if (sb->s_blocksize == 0)
1227                 sb->s_blocksize = nfs_block_bits(server->wsize,
1228                                                  &sb->s_blocksize_bits);
1229
1230         if (server->flags & NFS_MOUNT_NOAC)
1231                 sb->s_flags |= MS_SYNCHRONOUS;
1232
1233         nfs_super_set_maxbytes(sb, server->maxfilesize);
1234 }
1235
1236 /*
1237  * Finish setting up an NFS2/3 superblock
1238  */
1239 static void nfs_fill_super(struct super_block *sb,
1240                            struct nfs_parsed_mount_data *data)
1241 {
1242         struct nfs_server *server = NFS_SB(sb);
1243
1244         sb->s_blocksize_bits = 0;
1245         sb->s_blocksize = 0;
1246         if (data->bsize)
1247                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1248
1249         if (server->flags & NFS_MOUNT_VER3) {
1250                 /* The VFS shouldn't apply the umask to mode bits. We will do
1251                  * so ourselves when necessary.
1252                  */
1253                 sb->s_flags |= MS_POSIXACL;
1254                 sb->s_time_gran = 1;
1255         }
1256
1257         sb->s_op = &nfs_sops;
1258         nfs_initialise_sb(sb);
1259 }
1260
1261 /*
1262  * Finish setting up a cloned NFS2/3 superblock
1263  */
1264 static void nfs_clone_super(struct super_block *sb,
1265                             const struct super_block *old_sb)
1266 {
1267         struct nfs_server *server = NFS_SB(sb);
1268
1269         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1270         sb->s_blocksize = old_sb->s_blocksize;
1271         sb->s_maxbytes = old_sb->s_maxbytes;
1272
1273         if (server->flags & NFS_MOUNT_VER3) {
1274                 /* The VFS shouldn't apply the umask to mode bits. We will do
1275                  * so ourselves when necessary.
1276                  */
1277                 sb->s_flags |= MS_POSIXACL;
1278                 sb->s_time_gran = 1;
1279         }
1280
1281         sb->s_op = old_sb->s_op;
1282         nfs_initialise_sb(sb);
1283 }
1284
1285 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1286
1287 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1288 {
1289         const struct nfs_server *a = s->s_fs_info;
1290         const struct rpc_clnt *clnt_a = a->client;
1291         const struct rpc_clnt *clnt_b = b->client;
1292
1293         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1294                 goto Ebusy;
1295         if (a->nfs_client != b->nfs_client)
1296                 goto Ebusy;
1297         if (a->flags != b->flags)
1298                 goto Ebusy;
1299         if (a->wsize != b->wsize)
1300                 goto Ebusy;
1301         if (a->rsize != b->rsize)
1302                 goto Ebusy;
1303         if (a->acregmin != b->acregmin)
1304                 goto Ebusy;
1305         if (a->acregmax != b->acregmax)
1306                 goto Ebusy;
1307         if (a->acdirmin != b->acdirmin)
1308                 goto Ebusy;
1309         if (a->acdirmax != b->acdirmax)
1310                 goto Ebusy;
1311         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1312                 goto Ebusy;
1313         return 1;
1314 Ebusy:
1315         return 0;
1316 }
1317
1318 struct nfs_sb_mountdata {
1319         struct nfs_server *server;
1320         int mntflags;
1321 };
1322
1323 static int nfs_set_super(struct super_block *s, void *data)
1324 {
1325         struct nfs_sb_mountdata *sb_mntdata = data;
1326         struct nfs_server *server = sb_mntdata->server;
1327         int ret;
1328
1329         s->s_flags = sb_mntdata->mntflags;
1330         s->s_fs_info = server;
1331         ret = set_anon_super(s, server);
1332         if (ret == 0)
1333                 server->s_dev = s->s_dev;
1334         return ret;
1335 }
1336
1337 static int nfs_compare_super(struct super_block *sb, void *data)
1338 {
1339         struct nfs_sb_mountdata *sb_mntdata = data;
1340         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1341         int mntflags = sb_mntdata->mntflags;
1342
1343         if (memcmp(&old->nfs_client->cl_addr,
1344                                 &server->nfs_client->cl_addr,
1345                                 sizeof(old->nfs_client->cl_addr)) != 0)
1346                 return 0;
1347         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1348         if (old->flags & NFS_MOUNT_UNSHARED)
1349                 return 0;
1350         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1351                 return 0;
1352         return nfs_compare_mount_options(sb, server, mntflags);
1353 }
1354
1355 static int nfs_get_sb(struct file_system_type *fs_type,
1356         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1357 {
1358         struct nfs_server *server = NULL;
1359         struct super_block *s;
1360         struct nfs_fh mntfh;
1361         struct nfs_parsed_mount_data data;
1362         struct dentry *mntroot;
1363         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1364         struct nfs_sb_mountdata sb_mntdata = {
1365                 .mntflags = flags,
1366         };
1367         int error;
1368
1369         /* Validate the mount data */
1370         error = nfs_validate_mount_data(raw_data, &data, &mntfh, dev_name);
1371         if (error < 0)
1372                 goto out;
1373
1374         /* Get a volume representation */
1375         server = nfs_create_server(&data, &mntfh);
1376         if (IS_ERR(server)) {
1377                 error = PTR_ERR(server);
1378                 goto out;
1379         }
1380         sb_mntdata.server = server;
1381
1382         if (server->flags & NFS_MOUNT_UNSHARED)
1383                 compare_super = NULL;
1384
1385         /* Get a superblock - note that we may end up sharing one that already exists */
1386         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1387         if (IS_ERR(s)) {
1388                 error = PTR_ERR(s);
1389                 goto out_err_nosb;
1390         }
1391
1392         if (s->s_fs_info != server) {
1393                 nfs_free_server(server);
1394                 server = NULL;
1395         }
1396
1397         if (!s->s_root) {
1398                 /* initial superblock/root creation */
1399                 nfs_fill_super(s, &data);
1400         }
1401
1402         mntroot = nfs_get_root(s, &mntfh);
1403         if (IS_ERR(mntroot)) {
1404                 error = PTR_ERR(mntroot);
1405                 goto error_splat_super;
1406         }
1407
1408         s->s_flags |= MS_ACTIVE;
1409         mnt->mnt_sb = s;
1410         mnt->mnt_root = mntroot;
1411         error = 0;
1412
1413 out:
1414         kfree(data.nfs_server.hostname);
1415         return error;
1416
1417 out_err_nosb:
1418         nfs_free_server(server);
1419         goto out;
1420
1421 error_splat_super:
1422         up_write(&s->s_umount);
1423         deactivate_super(s);
1424         goto out;
1425 }
1426
1427 /*
1428  * Destroy an NFS2/3 superblock
1429  */
1430 static void nfs_kill_super(struct super_block *s)
1431 {
1432         struct nfs_server *server = NFS_SB(s);
1433
1434         kill_anon_super(s);
1435         nfs_free_server(server);
1436 }
1437
1438 /*
1439  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
1440  */
1441 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
1442                            const char *dev_name, void *raw_data,
1443                            struct vfsmount *mnt)
1444 {
1445         struct nfs_clone_mount *data = raw_data;
1446         struct super_block *s;
1447         struct nfs_server *server;
1448         struct dentry *mntroot;
1449         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1450         struct nfs_sb_mountdata sb_mntdata = {
1451                 .mntflags = flags,
1452         };
1453         int error;
1454
1455         dprintk("--> nfs_xdev_get_sb()\n");
1456
1457         /* create a new volume representation */
1458         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1459         if (IS_ERR(server)) {
1460                 error = PTR_ERR(server);
1461                 goto out_err_noserver;
1462         }
1463         sb_mntdata.server = server;
1464
1465         if (server->flags & NFS_MOUNT_UNSHARED)
1466                 compare_super = NULL;
1467
1468         /* Get a superblock - note that we may end up sharing one that already exists */
1469         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1470         if (IS_ERR(s)) {
1471                 error = PTR_ERR(s);
1472                 goto out_err_nosb;
1473         }
1474
1475         if (s->s_fs_info != server) {
1476                 nfs_free_server(server);
1477                 server = NULL;
1478         }
1479
1480         if (!s->s_root) {
1481                 /* initial superblock/root creation */
1482                 nfs_clone_super(s, data->sb);
1483         }
1484
1485         mntroot = nfs_get_root(s, data->fh);
1486         if (IS_ERR(mntroot)) {
1487                 error = PTR_ERR(mntroot);
1488                 goto error_splat_super;
1489         }
1490         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
1491                 dput(mntroot);
1492                 error = -ESTALE;
1493                 goto error_splat_super;
1494         }
1495
1496         s->s_flags |= MS_ACTIVE;
1497         mnt->mnt_sb = s;
1498         mnt->mnt_root = mntroot;
1499
1500         dprintk("<-- nfs_xdev_get_sb() = 0\n");
1501         return 0;
1502
1503 out_err_nosb:
1504         nfs_free_server(server);
1505 out_err_noserver:
1506         dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
1507         return error;
1508
1509 error_splat_super:
1510         up_write(&s->s_umount);
1511         deactivate_super(s);
1512         dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
1513         return error;
1514 }
1515
1516 #ifdef CONFIG_NFS_V4
1517
1518 /*
1519  * Finish setting up a cloned NFS4 superblock
1520  */
1521 static void nfs4_clone_super(struct super_block *sb,
1522                             const struct super_block *old_sb)
1523 {
1524         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1525         sb->s_blocksize = old_sb->s_blocksize;
1526         sb->s_maxbytes = old_sb->s_maxbytes;
1527         sb->s_time_gran = 1;
1528         sb->s_op = old_sb->s_op;
1529         nfs_initialise_sb(sb);
1530 }
1531
1532 /*
1533  * Set up an NFS4 superblock
1534  */
1535 static void nfs4_fill_super(struct super_block *sb)
1536 {
1537         sb->s_time_gran = 1;
1538         sb->s_op = &nfs4_sops;
1539         nfs_initialise_sb(sb);
1540 }
1541
1542 /*
1543  * Validate NFSv4 mount options
1544  */
1545 static int nfs4_validate_mount_data(void *options,
1546                                     struct nfs_parsed_mount_data *args,
1547                                     const char *dev_name)
1548 {
1549         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
1550         char *c;
1551
1552         memset(args, 0, sizeof(*args));
1553
1554         if (data == NULL)
1555                 goto out_no_data;
1556
1557         args->rsize             = NFS_MAX_FILE_IO_SIZE;
1558         args->wsize             = NFS_MAX_FILE_IO_SIZE;
1559         args->timeo             = 600;
1560         args->retrans           = 2;
1561         args->acregmin          = 3;
1562         args->acregmax          = 60;
1563         args->acdirmin          = 30;
1564         args->acdirmax          = 60;
1565         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1566
1567         switch (data->version) {
1568         case 1:
1569                 if (data->host_addrlen != sizeof(args->nfs_server.address))
1570                         goto out_no_address;
1571                 if (copy_from_user(&args->nfs_server.address,
1572                                    data->host_addr,
1573                                    sizeof(args->nfs_server.address)))
1574                         return -EFAULT;
1575                 if (args->nfs_server.address.sin_port == 0)
1576                         args->nfs_server.address.sin_port = htons(NFS_PORT);
1577                 if (!nfs_verify_server_address((struct sockaddr *)
1578                                                 &args->nfs_server.address))
1579                         goto out_no_address;
1580
1581                 switch (data->auth_flavourlen) {
1582                 case 0:
1583                         args->auth_flavors[0] = RPC_AUTH_UNIX;
1584                         break;
1585                 case 1:
1586                         if (copy_from_user(&args->auth_flavors[0],
1587                                            data->auth_flavours,
1588                                            sizeof(args->auth_flavors[0])))
1589                                 return -EFAULT;
1590                         break;
1591                 default:
1592                         goto out_inval_auth;
1593                 }
1594
1595                 c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
1596                 if (IS_ERR(c))
1597                         return PTR_ERR(c);
1598                 args->nfs_server.hostname = c;
1599
1600                 c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
1601                 if (IS_ERR(c))
1602                         return PTR_ERR(c);
1603                 args->nfs_server.export_path = c;
1604                 dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
1605
1606                 c = strndup_user(data->client_addr.data, 16);
1607                 if (IS_ERR(c))
1608                         return PTR_ERR(c);
1609                 args->client_address = c;
1610
1611                 /*
1612                  * Translate to nfs_parsed_mount_data, which nfs4_fill_super
1613                  * can deal with.
1614                  */
1615
1616                 args->flags     = data->flags & NFS4_MOUNT_FLAGMASK;
1617                 args->rsize     = data->rsize;
1618                 args->wsize     = data->wsize;
1619                 args->timeo     = data->timeo;
1620                 args->retrans   = data->retrans;
1621                 args->acregmin  = data->acregmin;
1622                 args->acregmax  = data->acregmax;
1623                 args->acdirmin  = data->acdirmin;
1624                 args->acdirmax  = data->acdirmax;
1625                 args->nfs_server.protocol = data->proto;
1626
1627                 break;
1628         default: {
1629                 unsigned int len;
1630
1631                 if (nfs_parse_mount_options((char *)options, args) == 0)
1632                         return -EINVAL;
1633
1634                 if (args->nfs_server.address.sin_port == 0)
1635                         args->nfs_server.address.sin_port = htons(NFS_PORT);
1636                 if (!nfs_verify_server_address((struct sockaddr *)
1637                                                 &args->nfs_server.address))
1638                         return -EINVAL;
1639
1640                 switch (args->auth_flavor_len) {
1641                 case 0:
1642                         args->auth_flavors[0] = RPC_AUTH_UNIX;
1643                         break;
1644                 case 1:
1645                         break;
1646                 default:
1647                         goto out_inval_auth;
1648                 }
1649
1650                 /*
1651                  * Split "dev_name" into "hostname:mntpath".
1652                  */
1653                 c = strchr(dev_name, ':');
1654                 if (c == NULL)
1655                         return -EINVAL;
1656                 /* while calculating len, pretend ':' is '\0' */
1657                 len = c - dev_name;
1658                 if (len > NFS4_MAXNAMLEN)
1659                         return -ENAMETOOLONG;
1660                 args->nfs_server.hostname = kzalloc(len, GFP_KERNEL);
1661                 if (args->nfs_server.hostname == NULL)
1662                         return -ENOMEM;
1663                 strncpy(args->nfs_server.hostname, dev_name, len - 1);
1664
1665                 c++;                    /* step over the ':' */
1666                 len = strlen(c);
1667                 if (len > NFS4_MAXPATHLEN)
1668                         return -ENAMETOOLONG;
1669                 args->nfs_server.export_path = kzalloc(len + 1, GFP_KERNEL);
1670                 if (args->nfs_server.export_path == NULL)
1671                         return -ENOMEM;
1672                 strncpy(args->nfs_server.export_path, c, len);
1673
1674                 dprintk("MNTPATH: %s\n", args->nfs_server.export_path);
1675
1676                 if (args->client_address == NULL)
1677                         goto out_no_client_address;
1678
1679                 break;
1680                 }
1681         }
1682
1683         return 0;
1684
1685 out_no_data:
1686         dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
1687         return -EINVAL;
1688
1689 out_inval_auth:
1690         dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
1691                  data->auth_flavourlen);
1692         return -EINVAL;
1693
1694 out_no_address:
1695         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
1696         return -EINVAL;
1697
1698 out_no_client_address:
1699         dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
1700         return -EINVAL;
1701 }
1702
1703 /*
1704  * Get the superblock for an NFS4 mountpoint
1705  */
1706 static int nfs4_get_sb(struct file_system_type *fs_type,
1707         int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1708 {
1709         struct nfs_parsed_mount_data data;
1710         struct super_block *s;
1711         struct nfs_server *server;
1712         struct nfs_fh mntfh;
1713         struct dentry *mntroot;
1714         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1715         struct nfs_sb_mountdata sb_mntdata = {
1716                 .mntflags = flags,
1717         };
1718         int error;
1719
1720         /* Validate the mount data */
1721         error = nfs4_validate_mount_data(raw_data, &data, dev_name);
1722         if (error < 0)
1723                 goto out;
1724
1725         /* Get a volume representation */
1726         server = nfs4_create_server(&data, &mntfh);
1727         if (IS_ERR(server)) {
1728                 error = PTR_ERR(server);
1729                 goto out;
1730         }
1731         sb_mntdata.server = server;
1732
1733         if (server->flags & NFS4_MOUNT_UNSHARED)
1734                 compare_super = NULL;
1735
1736         /* Get a superblock - note that we may end up sharing one that already exists */
1737         s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1738         if (IS_ERR(s)) {
1739                 error = PTR_ERR(s);
1740                 goto out_free;
1741         }
1742
1743         if (s->s_fs_info != server) {
1744                 nfs_free_server(server);
1745                 server = NULL;
1746         }
1747
1748         if (!s->s_root) {
1749                 /* initial superblock/root creation */
1750                 nfs4_fill_super(s);
1751         }
1752
1753         mntroot = nfs4_get_root(s, &mntfh);
1754         if (IS_ERR(mntroot)) {
1755                 error = PTR_ERR(mntroot);
1756                 goto error_splat_super;
1757         }
1758
1759         s->s_flags |= MS_ACTIVE;
1760         mnt->mnt_sb = s;
1761         mnt->mnt_root = mntroot;
1762         error = 0;
1763
1764 out:
1765         kfree(data.client_address);
1766         kfree(data.nfs_server.export_path);
1767         kfree(data.nfs_server.hostname);
1768         return error;
1769
1770 out_free:
1771         nfs_free_server(server);
1772         goto out;
1773
1774 error_splat_super:
1775         up_write(&s->s_umount);
1776         deactivate_super(s);
1777         goto out;
1778 }
1779
1780 static void nfs4_kill_super(struct super_block *sb)
1781 {
1782         struct nfs_server *server = NFS_SB(sb);
1783
1784         nfs_return_all_delegations(sb);
1785         kill_anon_super(sb);
1786
1787         nfs4_renewd_prepare_shutdown(server);
1788         nfs_free_server(server);
1789 }
1790
1791 /*
1792  * Clone an NFS4 server record on xdev traversal (FSID-change)
1793  */
1794 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
1795                             const char *dev_name, void *raw_data,
1796                             struct vfsmount *mnt)
1797 {
1798         struct nfs_clone_mount *data = raw_data;
1799         struct super_block *s;
1800         struct nfs_server *server;
1801         struct dentry *mntroot;
1802         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1803         struct nfs_sb_mountdata sb_mntdata = {
1804                 .mntflags = flags,
1805         };
1806         int error;
1807
1808         dprintk("--> nfs4_xdev_get_sb()\n");
1809
1810         /* create a new volume representation */
1811         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1812         if (IS_ERR(server)) {
1813                 error = PTR_ERR(server);
1814                 goto out_err_noserver;
1815         }
1816         sb_mntdata.server = server;
1817
1818         if (server->flags & NFS4_MOUNT_UNSHARED)
1819                 compare_super = NULL;
1820
1821         /* Get a superblock - note that we may end up sharing one that already exists */
1822         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1823         if (IS_ERR(s)) {
1824                 error = PTR_ERR(s);
1825                 goto out_err_nosb;
1826         }
1827
1828         if (s->s_fs_info != server) {
1829                 nfs_free_server(server);
1830                 server = NULL;
1831         }
1832
1833         if (!s->s_root) {
1834                 /* initial superblock/root creation */
1835                 nfs4_clone_super(s, data->sb);
1836         }
1837
1838         mntroot = nfs4_get_root(s, data->fh);
1839         if (IS_ERR(mntroot)) {
1840                 error = PTR_ERR(mntroot);
1841                 goto error_splat_super;
1842         }
1843         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
1844                 dput(mntroot);
1845                 error = -ESTALE;
1846                 goto error_splat_super;
1847         }
1848
1849         s->s_flags |= MS_ACTIVE;
1850         mnt->mnt_sb = s;
1851         mnt->mnt_root = mntroot;
1852
1853         dprintk("<-- nfs4_xdev_get_sb() = 0\n");
1854         return 0;
1855
1856 out_err_nosb:
1857         nfs_free_server(server);
1858 out_err_noserver:
1859         dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
1860         return error;
1861
1862 error_splat_super:
1863         up_write(&s->s_umount);
1864         deactivate_super(s);
1865         dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
1866         return error;
1867 }
1868
1869 /*
1870  * Create an NFS4 server record on referral traversal
1871  */
1872 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
1873                                 const char *dev_name, void *raw_data,
1874                                 struct vfsmount *mnt)
1875 {
1876         struct nfs_clone_mount *data = raw_data;
1877         struct super_block *s;
1878         struct nfs_server *server;
1879         struct dentry *mntroot;
1880         struct nfs_fh mntfh;
1881         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1882         struct nfs_sb_mountdata sb_mntdata = {
1883                 .mntflags = flags,
1884         };
1885         int error;
1886
1887         dprintk("--> nfs4_referral_get_sb()\n");
1888
1889         /* create a new volume representation */
1890         server = nfs4_create_referral_server(data, &mntfh);
1891         if (IS_ERR(server)) {
1892                 error = PTR_ERR(server);
1893                 goto out_err_noserver;
1894         }
1895         sb_mntdata.server = server;
1896
1897         if (server->flags & NFS4_MOUNT_UNSHARED)
1898                 compare_super = NULL;
1899
1900         /* Get a superblock - note that we may end up sharing one that already exists */
1901         s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1902         if (IS_ERR(s)) {
1903                 error = PTR_ERR(s);
1904                 goto out_err_nosb;
1905         }
1906
1907         if (s->s_fs_info != server) {
1908                 nfs_free_server(server);
1909                 server = NULL;
1910         }
1911
1912         if (!s->s_root) {
1913                 /* initial superblock/root creation */
1914                 nfs4_fill_super(s);
1915         }
1916
1917         mntroot = nfs4_get_root(s, &mntfh);
1918         if (IS_ERR(mntroot)) {
1919                 error = PTR_ERR(mntroot);
1920                 goto error_splat_super;
1921         }
1922         if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
1923                 dput(mntroot);
1924                 error = -ESTALE;
1925                 goto error_splat_super;
1926         }
1927
1928         s->s_flags |= MS_ACTIVE;
1929         mnt->mnt_sb = s;
1930         mnt->mnt_root = mntroot;
1931
1932         dprintk("<-- nfs4_referral_get_sb() = 0\n");
1933         return 0;
1934
1935 out_err_nosb:
1936         nfs_free_server(server);
1937 out_err_noserver:
1938         dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
1939         return error;
1940
1941 error_splat_super:
1942         up_write(&s->s_umount);
1943         deactivate_super(s);
1944         dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
1945         return error;
1946 }
1947
1948 #endif /* CONFIG_NFS_V4 */