fs/nfs/super.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/nfs/super.c
   4  *
   5  *  Copyright (C) 1992  Rick Sladkey
   6  *
   7  *  nfs superblock handling functions
   8  *
   9  *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
  10  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
  11  *
  12  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
  13  *  J.S.Peatfield@damtp.cam.ac.uk
  14  *
  15  *  Split from inode.c by David Howells <dhowells@redhat.com>
  16  *
  17  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
  18  *   particular server are held in the same superblock
  19  * - NFS superblocks can have several effective roots to the dentry tree
  20  * - directory type roots are spliced into the tree when a path from one root reaches the root
  21  *   of another (see nfs_lookup())
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26
  27 #include <linux/time.h>
  28 #include <linux/kernel.h>
  29 #include <linux/mm.h>
  30 #include <linux/string.h>
  31 #include <linux/stat.h>
  32 #include <linux/errno.h>
  33 #include <linux/unistd.h>
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/addr.h>
  36 #include <linux/sunrpc/stats.h>
  37 #include <linux/sunrpc/metrics.h>
  38 #include <linux/sunrpc/xprtsock.h>
  39 #include <linux/sunrpc/xprtrdma.h>
  40 #include <linux/nfs_fs.h>
  41 #include <linux/nfs_mount.h>
  42 #include <linux/nfs4_mount.h>
  43 #include <linux/lockd/bind.h>
  44 #include <linux/seq_file.h>
  45 #include <linux/mount.h>
  46 #include <linux/namei.h>
  47 #include <linux/vfs.h>
  48 #include <linux/inet.h>
  49 #include <linux/in6.h>
  50 #include <linux/slab.h>
  51 #include <net/ipv6.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/nfs_xdr.h>
  54 #include <linux/magic.h>
  55 #include <linux/parser.h>
  56 #include <linux/nsproxy.h>
  57 #include <linux/rcupdate.h>
  58
  59 #include <linux/uaccess.h>
  60
  61 #include "nfs4_fs.h"
  62 #include "callback.h"
  63 #include "delegation.h"
  64 #include "iostat.h"
  65 #include "internal.h"
  66 #include "fscache.h"
  67 #include "nfs4session.h"
  68 #include "pnfs.h"
  69 #include "nfs.h"
  70
  71 #define NFSDBG_FACILITY         NFSDBG_VFS
  72
  73 static struct dentry *nfs_prepared_mount(struct file_system_type *fs_type,
  74                 int flags, const char *dev_name, void *raw_data);
  75
  76 struct file_system_type nfs_fs_type = {
  77         .owner          = THIS_MODULE,
  78         .name           = "nfs",
  79         .mount          = nfs_fs_mount,
  80         .kill_sb        = nfs_kill_super,
  81         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
  82 };
  83 MODULE_ALIAS_FS("nfs");
  84 EXPORT_SYMBOL_GPL(nfs_fs_type);
  85
  86 struct file_system_type nfs_prepared_fs_type = {
  87         .owner          = THIS_MODULE,
  88         .name           = "nfs",
  89         .mount          = nfs_prepared_mount,
  90         .kill_sb        = nfs_kill_super,
  91         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
  92 };
  93 EXPORT_SYMBOL_GPL(nfs_prepared_fs_type);
  94
  95 const struct super_operations nfs_sops = {
  96         .alloc_inode    = nfs_alloc_inode,
  97         .free_inode     = nfs_free_inode,
  98         .write_inode    = nfs_write_inode,
  99         .drop_inode     = nfs_drop_inode,
 100         .statfs         = nfs_statfs,
 101         .evict_inode    = nfs_evict_inode,
 102         .umount_begin   = nfs_umount_begin,
 103         .show_options   = nfs_show_options,
 104         .show_devname   = nfs_show_devname,
 105         .show_path      = nfs_show_path,
 106         .show_stats     = nfs_show_stats,
 107         .remount_fs     = nfs_remount,
 108 };
 109 EXPORT_SYMBOL_GPL(nfs_sops);
 110
 111 #if IS_ENABLED(CONFIG_NFS_V4)
 112 struct file_system_type nfs4_fs_type = {
 113         .owner          = THIS_MODULE,
 114         .name           = "nfs4",
 115         .mount          = nfs_fs_mount,
 116         .kill_sb        = nfs_kill_super,
 117         .fs_flags       = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
 118 };
 119 MODULE_ALIAS_FS("nfs4");
 120 MODULE_ALIAS("nfs4");
 121 EXPORT_SYMBOL_GPL(nfs4_fs_type);
 122
 123 static int __init register_nfs4_fs(void)
 124 {
 125         return register_filesystem(&nfs4_fs_type);
 126 }
 127
 128 static void unregister_nfs4_fs(void)
 129 {
 130         unregister_filesystem(&nfs4_fs_type);
 131 }
 132 #else
 133 static int __init register_nfs4_fs(void)
 134 {
 135         return 0;
 136 }
 137
 138 static void unregister_nfs4_fs(void)
 139 {
 140 }
 141 #endif
 142
 143 static struct shrinker acl_shrinker = {
 144         .count_objects  = nfs_access_cache_count,
 145         .scan_objects   = nfs_access_cache_scan,
 146         .seeks          = DEFAULT_SEEKS,
 147 };
 148
 149 /*
 150  * Register the NFS filesystems
 151  */
 152 int __init register_nfs_fs(void)
 153 {
 154         int ret;
 155
 156         ret = register_filesystem(&nfs_fs_type);
 157         if (ret < 0)
 158                 goto error_0;
 159
 160         ret = register_nfs4_fs();
 161         if (ret < 0)
 162                 goto error_1;
 163
 164         ret = nfs_register_sysctl();
 165         if (ret < 0)
 166                 goto error_2;
 167         ret = register_shrinker(&acl_shrinker);
 168         if (ret < 0)
 169                 goto error_3;
 170         return 0;
 171 error_3:
 172         nfs_unregister_sysctl();
 173 error_2:
 174         unregister_nfs4_fs();
 175 error_1:
 176         unregister_filesystem(&nfs_fs_type);
 177 error_0:
 178         return ret;
 179 }
 180
 181 /*
 182  * Unregister the NFS filesystems
 183  */
 184 void __exit unregister_nfs_fs(void)
 185 {
 186         unregister_shrinker(&acl_shrinker);
 187         nfs_unregister_sysctl();
 188         unregister_nfs4_fs();
 189         unregister_filesystem(&nfs_fs_type);
 190 }
 191
 192 bool nfs_sb_active(struct super_block *sb)
 193 {
 194         struct nfs_server *server = NFS_SB(sb);
 195
 196         if (!atomic_inc_not_zero(&sb->s_active))
 197                 return false;
 198         if (atomic_inc_return(&server->active) != 1)
 199                 atomic_dec(&sb->s_active);
 200         return true;
 201 }
 202 EXPORT_SYMBOL_GPL(nfs_sb_active);
 203
 204 void nfs_sb_deactive(struct super_block *sb)
 205 {
 206         struct nfs_server *server = NFS_SB(sb);
 207
 208         if (atomic_dec_and_test(&server->active))
 209                 deactivate_super(sb);
 210 }
 211 EXPORT_SYMBOL_GPL(nfs_sb_deactive);
 212
 213 /*
 214  * Deliver file system statistics to userspace
 215  */
 216 int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 217 {
 218         struct nfs_server *server = NFS_SB(dentry->d_sb);
 219         unsigned char blockbits;
 220         unsigned long blockres;
 221         struct nfs_fh *fh = NFS_FH(d_inode(dentry));
 222         struct nfs_fsstat res;
 223         int error = -ENOMEM;
 224
 225         res.fattr = nfs_alloc_fattr();
 226         if (res.fattr == NULL)
 227                 goto out_err;
 228
 229         error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
 230         if (unlikely(error == -ESTALE)) {
 231                 struct dentry *pd_dentry;
 232
 233                 pd_dentry = dget_parent(dentry);
 234                 nfs_zap_caches(d_inode(pd_dentry));
 235                 dput(pd_dentry);
 236         }
 237         nfs_free_fattr(res.fattr);
 238         if (error < 0)
 239                 goto out_err;
 240
 241         buf->f_type = NFS_SUPER_MAGIC;
 242
 243         /*
 244          * Current versions of glibc do not correctly handle the
 245          * case where f_frsize != f_bsize.  Eventually we want to
 246          * report the value of wtmult in this field.
 247          */
 248         buf->f_frsize = dentry->d_sb->s_blocksize;
 249
 250         /*
 251          * On most *nix systems, f_blocks, f_bfree, and f_bavail
 252          * are reported in units of f_frsize.  Linux hasn't had
 253          * an f_frsize field in its statfs struct until recently,
 254          * thus historically Linux's sys_statfs reports these
 255          * fields in units of f_bsize.
 256          */
 257         buf->f_bsize = dentry->d_sb->s_blocksize;
 258         blockbits = dentry->d_sb->s_blocksize_bits;
 259         blockres = (1 << blockbits) - 1;
 260         buf->f_blocks = (res.tbytes + blockres) >> blockbits;
 261         buf->f_bfree = (res.fbytes + blockres) >> blockbits;
 262         buf->f_bavail = (res.abytes + blockres) >> blockbits;
 263
 264         buf->f_files = res.tfiles;
 265         buf->f_ffree = res.afiles;
 266
 267         buf->f_namelen = server->namelen;
 268
 269         return 0;
 270
 271  out_err:
 272         dprintk("%s: statfs error = %d\n", __func__, -error);
 273         return error;
 274 }
 275 EXPORT_SYMBOL_GPL(nfs_statfs);
 276
 277 /*
 278  * Map the security flavour number to a name
 279  */
 280 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 281 {
 282         static const struct {
 283                 rpc_authflavor_t flavour;
 284                 const char *str;
 285         } sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
 286                 /* update NFS_AUTH_INFO_MAX_FLAVORS when this list changes! */
 287                 { RPC_AUTH_NULL, "null" },
 288                 { RPC_AUTH_UNIX, "sys" },
 289                 { RPC_AUTH_GSS_KRB5, "krb5" },
 290                 { RPC_AUTH_GSS_KRB5I, "krb5i" },
 291                 { RPC_AUTH_GSS_KRB5P, "krb5p" },
 292                 { RPC_AUTH_GSS_LKEY, "lkey" },
 293                 { RPC_AUTH_GSS_LKEYI, "lkeyi" },
 294                 { RPC_AUTH_GSS_LKEYP, "lkeyp" },
 295                 { RPC_AUTH_GSS_SPKM, "spkm" },
 296                 { RPC_AUTH_GSS_SPKMI, "spkmi" },
 297                 { RPC_AUTH_GSS_SPKMP, "spkmp" },
 298                 { UINT_MAX, "unknown" }
 299         };
 300         int i;
 301
 302         for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
 303                 if (sec_flavours[i].flavour == flavour)
 304                         break;
 305         }
 306         return sec_flavours[i].str;
 307 }
 308
 309 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
 310                                   int showdefaults)
 311 {
 312         struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
 313         char *proto = NULL;
 314
 315         switch (sap->sa_family) {
 316         case AF_INET:
 317                 switch (nfss->mountd_protocol) {
 318                 case IPPROTO_UDP:
 319                         proto = RPCBIND_NETID_UDP;
 320                         break;
 321                 case IPPROTO_TCP:
 322                         proto = RPCBIND_NETID_TCP;
 323                         break;
 324                 }
 325                 break;
 326         case AF_INET6:
 327                 switch (nfss->mountd_protocol) {
 328                 case IPPROTO_UDP:
 329                         proto = RPCBIND_NETID_UDP6;
 330                         break;
 331                 case IPPROTO_TCP:
 332                         proto = RPCBIND_NETID_TCP6;
 333                         break;
 334                 }
 335                 break;
 336         }
 337         if (proto || showdefaults)
 338                 seq_printf(m, ",mountproto=%s", proto ?: "auto");
 339 }
 340
 341 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
 342                                     int showdefaults)
 343 {
 344         struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
 345
 346         if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
 347                 return;
 348
 349         switch (sap->sa_family) {
 350         case AF_INET: {
 351                 struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 352                 seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
 353                 break;
 354         }
 355         case AF_INET6: {
 356                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 357                 seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
 358                 break;
 359         }
 360         default:
 361                 if (showdefaults)
 362                         seq_puts(m, ",mountaddr=unspecified");
 363         }
 364
 365         if (nfss->mountd_version || showdefaults)
 366                 seq_printf(m, ",mountvers=%u", nfss->mountd_version);
 367         if ((nfss->mountd_port &&
 368                 nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
 369                 showdefaults)
 370                 seq_printf(m, ",mountport=%u", nfss->mountd_port);
 371
 372         nfs_show_mountd_netid(m, nfss, showdefaults);
 373 }
 374
 375 #if IS_ENABLED(CONFIG_NFS_V4)
 376 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
 377                                     int showdefaults)
 378 {
 379         struct nfs_client *clp = nfss->nfs_client;
 380
 381         seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
 382 }
 383 #else
 384 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
 385                                     int showdefaults)
 386 {
 387 }
 388 #endif
 389
 390 static void nfs_show_nfs_version(struct seq_file *m,
 391                 unsigned int version,
 392                 unsigned int minorversion)
 393 {
 394         seq_printf(m, ",vers=%u", version);
 395         if (version == 4)
 396                 seq_printf(m, ".%u", minorversion);
 397 }
 398
 399 /*
 400  * Describe the mount options in force on this server representation
 401  */
 402 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
 403                                    int showdefaults)
 404 {
 405         static const struct proc_nfs_info {
 406                 int flag;
 407                 const char *str;
 408                 const char *nostr;
 409         } nfs_info[] = {
 410                 { NFS_MOUNT_SOFT, ",soft", "" },
 411                 { NFS_MOUNT_SOFTERR, ",softerr", "" },
 412                 { NFS_MOUNT_POSIX, ",posix", "" },
 413                 { NFS_MOUNT_NOCTO, ",nocto", "" },
 414                 { NFS_MOUNT_NOAC, ",noac", "" },
 415                 { NFS_MOUNT_NONLM, ",nolock", "" },
 416                 { NFS_MOUNT_NOACL, ",noacl", "" },
 417                 { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
 418                 { NFS_MOUNT_UNSHARED, ",nosharecache", "" },
 419                 { NFS_MOUNT_NORESVPORT, ",noresvport", "" },
 420                 { 0, NULL, NULL }
 421         };
 422         const struct proc_nfs_info *nfs_infop;
 423         struct nfs_client *clp = nfss->nfs_client;
 424         u32 version = clp->rpc_ops->version;
 425         int local_flock, local_fcntl;
 426
 427         nfs_show_nfs_version(m, version, clp->cl_minorversion);
 428         seq_printf(m, ",rsize=%u", nfss->rsize);
 429         seq_printf(m, ",wsize=%u", nfss->wsize);
 430         if (nfss->bsize != 0)
 431                 seq_printf(m, ",bsize=%u", nfss->bsize);
 432         seq_printf(m, ",namlen=%u", nfss->namelen);
 433         if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
 434                 seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
 435         if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
 436                 seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
 437         if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
 438                 seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
 439         if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
 440                 seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
 441         if (!(nfss->flags & (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR)))
 442                         seq_puts(m, ",hard");
 443         for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
 444                 if (nfss->flags & nfs_infop->flag)
 445                         seq_puts(m, nfs_infop->str);
 446                 else
 447                         seq_puts(m, nfs_infop->nostr);
 448         }
 449         rcu_read_lock();
 450         seq_printf(m, ",proto=%s",
 451                    rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
 452         rcu_read_unlock();
 453         if (clp->cl_nconnect > 0)
 454                 seq_printf(m, ",nconnect=%u", clp->cl_nconnect);
 455         if (version == 4) {
 456                 if (nfss->port != NFS_PORT)
 457                         seq_printf(m, ",port=%u", nfss->port);
 458         } else
 459                 if (nfss->port)
 460                         seq_printf(m, ",port=%u", nfss->port);
 461
 462         seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
 463         seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
 464         seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
 465
 466         if (version != 4)
 467                 nfs_show_mountd_options(m, nfss, showdefaults);
 468         else
 469                 nfs_show_nfsv4_options(m, nfss, showdefaults);
 470
 471         if (nfss->options & NFS_OPTION_FSCACHE)
 472                 seq_puts(m, ",fsc");
 473
 474         if (nfss->options & NFS_OPTION_MIGRATION)
 475                 seq_puts(m, ",migration");
 476
 477         if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
 478                 if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
 479                         seq_puts(m, ",lookupcache=none");
 480                 else
 481                         seq_puts(m, ",lookupcache=pos");
 482         }
 483
 484         local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
 485         local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
 486
 487         if (!local_flock && !local_fcntl)
 488                 seq_puts(m, ",local_lock=none");
 489         else if (local_flock && local_fcntl)
 490                 seq_puts(m, ",local_lock=all");
 491         else if (local_flock)
 492                 seq_puts(m, ",local_lock=flock");
 493         else
 494                 seq_puts(m, ",local_lock=posix");
 495 }
 496
 497 /*
 498  * Describe the mount options on this VFS mountpoint
 499  */
 500 int nfs_show_options(struct seq_file *m, struct dentry *root)
 501 {
 502         struct nfs_server *nfss = NFS_SB(root->d_sb);
 503
 504         nfs_show_mount_options(m, nfss, 0);
 505
 506         rcu_read_lock();
 507         seq_printf(m, ",addr=%s",
 508                         rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
 509                                                         RPC_DISPLAY_ADDR));
 510         rcu_read_unlock();
 511
 512         return 0;
 513 }
 514 EXPORT_SYMBOL_GPL(nfs_show_options);
 515
 516 #if IS_ENABLED(CONFIG_NFS_V4)
 517 static void show_lease(struct seq_file *m, struct nfs_server *server)
 518 {
 519         struct nfs_client *clp = server->nfs_client;
 520         unsigned long expire;
 521
 522         seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
 523         expire = clp->cl_last_renewal + clp->cl_lease_time;
 524         seq_printf(m, ",lease_expired=%ld",
 525                    time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
 526 }
 527 #ifdef CONFIG_NFS_V4_1
 528 static void show_sessions(struct seq_file *m, struct nfs_server *server)
 529 {
 530         if (nfs4_has_session(server->nfs_client))
 531                 seq_puts(m, ",sessions");
 532 }
 533 #else
 534 static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
 535 #endif
 536 #endif
 537
 538 #ifdef CONFIG_NFS_V4_1
 539 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
 540 {
 541         seq_printf(m, ",pnfs=");
 542         if (server->pnfs_curr_ld)
 543                 seq_printf(m, "%s", server->pnfs_curr_ld->name);
 544         else
 545                 seq_printf(m, "not configured");
 546 }
 547
 548 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
 549 {
 550         if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
 551                 struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
 552                 seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
 553                            "date='%llu,%u'",
 554                            impl_id->name, impl_id->domain,
 555                            impl_id->date.seconds, impl_id->date.nseconds);
 556         }
 557 }
 558 #else
 559 #if IS_ENABLED(CONFIG_NFS_V4)
 560 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
 561 {
 562 }
 563 #endif
 564 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
 565 {
 566 }
 567 #endif
 568
 569 int nfs_show_devname(struct seq_file *m, struct dentry *root)
 570 {
 571         char *page = (char *) __get_free_page(GFP_KERNEL);
 572         char *devname, *dummy;
 573         int err = 0;
 574         if (!page)
 575                 return -ENOMEM;
 576         devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
 577         if (IS_ERR(devname))
 578                 err = PTR_ERR(devname);
 579         else
 580                 seq_escape(m, devname, " \t\n\\");
 581         free_page((unsigned long)page);
 582         return err;
 583 }
 584 EXPORT_SYMBOL_GPL(nfs_show_devname);
 585
 586 int nfs_show_path(struct seq_file *m, struct dentry *dentry)
 587 {
 588         seq_puts(m, "/");
 589         return 0;
 590 }
 591 EXPORT_SYMBOL_GPL(nfs_show_path);
 592
 593 /*
 594  * Present statistical information for this VFS mountpoint
 595  */
 596 int nfs_show_stats(struct seq_file *m, struct dentry *root)
 597 {
 598         int i, cpu;
 599         struct nfs_server *nfss = NFS_SB(root->d_sb);
 600         struct rpc_auth *auth = nfss->client->cl_auth;
 601         struct nfs_iostats totals = { };
 602
 603         seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
 604
 605         /*
 606          * Display all mount option settings
 607          */
 608         seq_puts(m, "\n\topts:\t");
 609         seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
 610         seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
 611         seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
 612         seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
 613         nfs_show_mount_options(m, nfss, 1);
 614
 615         seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
 616
 617         show_implementation_id(m, nfss);
 618
 619         seq_puts(m, "\n\tcaps:\t");
 620         seq_printf(m, "caps=0x%x", nfss->caps);
 621         seq_printf(m, ",wtmult=%u", nfss->wtmult);
 622         seq_printf(m, ",dtsize=%u", nfss->dtsize);
 623         seq_printf(m, ",bsize=%u", nfss->bsize);
 624         seq_printf(m, ",namlen=%u", nfss->namelen);
 625
 626 #if IS_ENABLED(CONFIG_NFS_V4)
 627         if (nfss->nfs_client->rpc_ops->version == 4) {
 628                 seq_puts(m, "\n\tnfsv4:\t");
 629                 seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 630                 seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
 631                 seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
 632                 seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 633                 show_sessions(m, nfss);
 634                 show_pnfs(m, nfss);
 635                 show_lease(m, nfss);
 636         }
 637 #endif
 638
 639         /*
 640          * Display security flavor in effect for this mount
 641          */
 642         seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
 643         if (auth->au_flavor)
 644                 seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
 645
 646         /*
 647          * Display superblock I/O counters
 648          */
 649         for_each_possible_cpu(cpu) {
 650                 struct nfs_iostats *stats;
 651
 652                 preempt_disable();
 653                 stats = per_cpu_ptr(nfss->io_stats, cpu);
 654
 655                 for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 656                         totals.events[i] += stats->events[i];
 657                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 658                         totals.bytes[i] += stats->bytes[i];
 659 #ifdef CONFIG_NFS_FSCACHE
 660                 for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
 661                         totals.fscache[i] += stats->fscache[i];
 662 #endif
 663
 664                 preempt_enable();
 665         }
 666
 667         seq_puts(m, "\n\tevents:\t");
 668         for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
 669                 seq_printf(m, "%lu ", totals.events[i]);
 670         seq_puts(m, "\n\tbytes:\t");
 671         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
 672                 seq_printf(m, "%Lu ", totals.bytes[i]);
 673 #ifdef CONFIG_NFS_FSCACHE
 674         if (nfss->options & NFS_OPTION_FSCACHE) {
 675                 seq_puts(m, "\n\tfsc:\t");
 676                 for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
 677                         seq_printf(m, "%Lu ", totals.fscache[i]);
 678         }
 679 #endif
 680         seq_putc(m, '\n');
 681
 682         rpc_clnt_show_stats(m, nfss->client);
 683
 684         return 0;
 685 }
 686 EXPORT_SYMBOL_GPL(nfs_show_stats);
 687
 688 /*
 689  * Begin unmount by attempting to remove all automounted mountpoints we added
 690  * in response to xdev traversals and referrals
 691  */
 692 void nfs_umount_begin(struct super_block *sb)
 693 {
 694         struct nfs_server *server;
 695         struct rpc_clnt *rpc;
 696
 697         server = NFS_SB(sb);
 698         /* -EIO all pending I/O */
 699         rpc = server->client_acl;
 700         if (!IS_ERR(rpc))
 701                 rpc_killall_tasks(rpc);
 702         rpc = server->client;
 703         if (!IS_ERR(rpc))
 704                 rpc_killall_tasks(rpc);
 705 }
 706 EXPORT_SYMBOL_GPL(nfs_umount_begin);
 707
 708 /*
 709  * Return true if 'match' is in auth_info or auth_info is empty.
 710  * Return false otherwise.
 711  */
 712 bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
 713                          rpc_authflavor_t match)
 714 {
 715         int i;
 716
 717         if (!auth_info->flavor_len)
 718                 return true;
 719
 720         for (i = 0; i < auth_info->flavor_len; i++) {
 721                 if (auth_info->flavors[i] == match)
 722                         return true;
 723         }
 724         return false;
 725 }
 726 EXPORT_SYMBOL_GPL(nfs_auth_info_match);
 727
 728 /*
 729  * Ensure that a specified authtype in args->auth_info is supported by
 730  * the server. Returns 0 and sets args->selected_flavor if it's ok, and
 731  * -EACCES if not.
 732  */
 733 static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
 734                         rpc_authflavor_t *server_authlist, unsigned int count)
 735 {
 736         rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
 737         bool found_auth_null = false;
 738         unsigned int i;
 739
 740         /*
 741          * If the sec= mount option is used, the specified flavor or AUTH_NULL
 742          * must be in the list returned by the server.
 743          *
 744          * AUTH_NULL has a special meaning when it's in the server list - it
 745          * means that the server will ignore the rpc creds, so any flavor
 746          * can be used but still use the sec= that was specified.
 747          *
 748          * Note also that the MNT procedure in MNTv1 does not return a list
 749          * of supported security flavors. In this case, nfs_mount() fabricates
 750          * a security flavor list containing just AUTH_NULL.
 751          */
 752         for (i = 0; i < count; i++) {
 753                 flavor = server_authlist[i];
 754
 755                 if (nfs_auth_info_match(&args->auth_info, flavor))
 756                         goto out;
 757
 758                 if (flavor == RPC_AUTH_NULL)
 759                         found_auth_null = true;
 760         }
 761
 762         if (found_auth_null) {
 763                 flavor = args->auth_info.flavors[0];
 764                 goto out;
 765         }
 766
 767         dfprintk(MOUNT,
 768                  "NFS: specified auth flavors not supported by server\n");
 769         return -EACCES;
 770
 771 out:
 772         args->selected_flavor = flavor;
 773         dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->selected_flavor);
 774         return 0;
 775 }
 776
 777 /*
 778  * Use the remote server's MOUNT service to request the NFS file handle
 779  * corresponding to the provided path.
 780  */
 781 static int nfs_request_mount(struct nfs_parsed_mount_data *args,
 782                              struct nfs_fh *root_fh,
 783                              rpc_authflavor_t *server_authlist,
 784                              unsigned int *server_authlist_len)
 785 {
 786         struct nfs_mount_request request = {
 787                 .sap            = (struct sockaddr *)
 788                                                 &args->mount_server.address,
 789                 .dirpath        = args->nfs_server.export_path,
 790                 .protocol       = args->mount_server.protocol,
 791                 .fh             = root_fh,
 792                 .noresvport     = args->flags & NFS_MOUNT_NORESVPORT,
 793                 .auth_flav_len  = server_authlist_len,
 794                 .auth_flavs     = server_authlist,
 795                 .net            = args->net,
 796         };
 797         int status;
 798
 799         if (args->mount_server.version == 0) {
 800                 switch (args->version) {
 801                         default:
 802                                 args->mount_server.version = NFS_MNT3_VERSION;
 803                                 break;
 804                         case 2:
 805                                 args->mount_server.version = NFS_MNT_VERSION;
 806                 }
 807         }
 808         request.version = args->mount_server.version;
 809
 810         if (args->mount_server.hostname)
 811                 request.hostname = args->mount_server.hostname;
 812         else
 813                 request.hostname = args->nfs_server.hostname;
 814
 815         /*
 816          * Construct the mount server's address.
 817          */
 818         if (args->mount_server.address.ss_family == AF_UNSPEC) {
 819                 memcpy(request.sap, &args->nfs_server.address,
 820                        args->nfs_server.addrlen);
 821                 args->mount_server.addrlen = args->nfs_server.addrlen;
 822         }
 823         request.salen = args->mount_server.addrlen;
 824         nfs_set_port(request.sap, &args->mount_server.port, 0);
 825
 826         /*
 827          * Now ask the mount server to map our export path
 828          * to a file handle.
 829          */
 830         status = nfs_mount(&request);
 831         if (status != 0) {
 832                 dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
 833                                 request.hostname, status);
 834                 return status;
 835         }
 836
 837         return 0;
 838 }
 839
 840 static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_info)
 841 {
 842         int status;
 843         unsigned int i;
 844         bool tried_auth_unix = false;
 845         bool auth_null_in_list = false;
 846         struct nfs_server *server = ERR_PTR(-EACCES);
 847         struct nfs_parsed_mount_data *args = mount_info->parsed;
 848         rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
 849         unsigned int authlist_len = ARRAY_SIZE(authlist);
 850         struct nfs_subversion *nfs_mod = mount_info->nfs_mod;
 851
 852         status = nfs_request_mount(args, mount_info->mntfh, authlist,
 853                                         &authlist_len);
 854         if (status)
 855                 return ERR_PTR(status);
 856
 857         /*
 858          * Was a sec= authflavor specified in the options? First, verify
 859          * whether the server supports it, and then just try to use it if so.
 860          */
 861         if (args->auth_info.flavor_len > 0) {
 862                 status = nfs_verify_authflavors(args, authlist, authlist_len);
 863                 dfprintk(MOUNT, "NFS: using auth flavor %u\n",
 864                          args->selected_flavor);
 865                 if (status)
 866                         return ERR_PTR(status);
 867                 return nfs_mod->rpc_ops->create_server(mount_info);
 868         }
 869
 870         /*
 871          * No sec= option was provided. RFC 2623, section 2.7 suggests we
 872          * SHOULD prefer the flavor listed first. However, some servers list
 873          * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
 874          */
 875         for (i = 0; i < authlist_len; ++i) {
 876                 rpc_authflavor_t flavor;
 877                 struct rpcsec_gss_info info;
 878
 879                 flavor = authlist[i];
 880                 switch (flavor) {
 881                 case RPC_AUTH_UNIX:
 882                         tried_auth_unix = true;
 883                         break;
 884                 case RPC_AUTH_NULL:
 885                         auth_null_in_list = true;
 886                         continue;
 887                 default:
 888                         if (rpcauth_get_gssinfo(flavor, &info) != 0)
 889                                 continue;
 890                         /* Fallthrough */
 891                 }
 892                 dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
 893                 args->selected_flavor = flavor;
 894                 server = nfs_mod->rpc_ops->create_server(mount_info);
 895                 if (!IS_ERR(server))
 896                         return server;
 897         }
 898
 899         /*
 900          * Nothing we tried so far worked. At this point, give up if we've
 901          * already tried AUTH_UNIX or if the server's list doesn't contain
 902          * AUTH_NULL
 903          */
 904         if (tried_auth_unix || !auth_null_in_list)
 905                 return server;
 906
 907         /* Last chance! Try AUTH_UNIX */
 908         dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
 909         args->selected_flavor = RPC_AUTH_UNIX;
 910         return nfs_mod->rpc_ops->create_server(mount_info);
 911 }
 912
 913 static struct dentry *nfs_fs_mount_common(int, const char *, struct nfs_mount_info *);
 914
 915 struct dentry *nfs_try_mount(int flags, const char *dev_name,
 916                              struct nfs_mount_info *mount_info)
 917 {
 918         struct nfs_subversion *nfs_mod = mount_info->nfs_mod;
 919         if (mount_info->parsed->need_mount)
 920                 mount_info->server = nfs_try_mount_request(mount_info);
 921         else
 922                 mount_info->server = nfs_mod->rpc_ops->create_server(mount_info);
 923
 924         return nfs_fs_mount_common(flags, dev_name, mount_info);
 925 }
 926 EXPORT_SYMBOL_GPL(nfs_try_mount);
 927
 928 #define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
 929                 | NFS_MOUNT_SECURE \
 930                 | NFS_MOUNT_TCP \
 931                 | NFS_MOUNT_VER3 \
 932                 | NFS_MOUNT_KERBEROS \
 933                 | NFS_MOUNT_NONLM \
 934                 | NFS_MOUNT_BROKEN_SUID \
 935                 | NFS_MOUNT_STRICTLOCK \
 936                 | NFS_MOUNT_LEGACY_INTERFACE)
 937
 938 #define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
 939                 ~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
 940
 941 static int
 942 nfs_compare_remount_data(struct nfs_server *nfss,
 943                          struct nfs_parsed_mount_data *data)
 944 {
 945         if ((data->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
 946             data->rsize != nfss->rsize ||
 947             data->wsize != nfss->wsize ||
 948             data->version != nfss->nfs_client->rpc_ops->version ||
 949             data->minorversion != nfss->nfs_client->cl_minorversion ||
 950             data->retrans != nfss->client->cl_timeout->to_retries ||
 951             !nfs_auth_info_match(&data->auth_info, nfss->client->cl_auth->au_flavor) ||
 952             data->acregmin != nfss->acregmin / HZ ||
 953             data->acregmax != nfss->acregmax / HZ ||
 954             data->acdirmin != nfss->acdirmin / HZ ||
 955             data->acdirmax != nfss->acdirmax / HZ ||
 956             data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
 957             (data->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
 958             data->nfs_server.port != nfss->port ||
 959             data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
 960             !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
 961                           (struct sockaddr *)&nfss->nfs_client->cl_addr))
 962                 return -EINVAL;
 963
 964         return 0;
 965 }
 966
 967 int
 968 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
 969 {
 970         int error;
 971         struct nfs_server *nfss = sb->s_fs_info;
 972         struct nfs_parsed_mount_data *data;
 973         struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
 974         struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
 975         u32 nfsvers = nfss->nfs_client->rpc_ops->version;
 976
 977         sync_filesystem(sb);
 978
 979         /*
 980          * Userspace mount programs that send binary options generally send
 981          * them populated with default values. We have no way to know which
 982          * ones were explicitly specified. Fall back to legacy behavior and
 983          * just return success.
 984          */
 985         if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
 986             (nfsvers <= 3 && (!options || (options->version >= 1 &&
 987                                            options->version <= 6))))
 988                 return 0;
 989
 990         data = nfs_alloc_parsed_mount_data();
 991         if (data == NULL)
 992                 return -ENOMEM;
 993
 994         /* fill out struct with values from existing mount */
 995         data->flags = nfss->flags;
 996         data->rsize = nfss->rsize;
 997         data->wsize = nfss->wsize;
 998         data->retrans = nfss->client->cl_timeout->to_retries;
 999         data->selected_flavor = nfss->client->cl_auth->au_flavor;
1000         data->acregmin = nfss->acregmin / HZ;
1001         data->acregmax = nfss->acregmax / HZ;
1002         data->acdirmin = nfss->acdirmin / HZ;
1003         data->acdirmax = nfss->acdirmax / HZ;
1004         data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
1005         data->nfs_server.port = nfss->port;
1006         data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
1007         data->version = nfsvers;
1008         data->minorversion = nfss->nfs_client->cl_minorversion;
1009         data->net = current->nsproxy->net_ns;
1010         memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1011                 data->nfs_server.addrlen);
1012
1013         /* overwrite those values with any that were specified */
1014         error = -EINVAL;
1015         if (!nfs_parse_mount_options((char *)options, data))
1016                 goto out;
1017
1018         /*
1019          * noac is a special case. It implies -o sync, but that's not
1020          * necessarily reflected in the mtab options. do_remount_sb
1021          * will clear SB_SYNCHRONOUS if -o sync wasn't specified in the
1022          * remount options, so we have to explicitly reset it.
1023          */
1024         if (data->flags & NFS_MOUNT_NOAC)
1025                 *flags |= SB_SYNCHRONOUS;
1026
1027         /* compare new mount options with old ones */
1028         error = nfs_compare_remount_data(nfss, data);
1029         if (!error)
1030                 error = security_sb_remount(sb, data->lsm_opts);
1031 out:
1032         nfs_free_parsed_mount_data(data);
1033         return error;
1034 }
1035 EXPORT_SYMBOL_GPL(nfs_remount);
1036
1037 /*
1038  * Finish setting up an NFS superblock
1039  */
1040 static void nfs_fill_super(struct super_block *sb, struct nfs_mount_info *mount_info)
1041 {
1042         struct nfs_parsed_mount_data *data = mount_info->parsed;
1043         struct nfs_server *server = NFS_SB(sb);
1044
1045         sb->s_blocksize_bits = 0;
1046         sb->s_blocksize = 0;
1047         sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
1048         sb->s_op = server->nfs_client->cl_nfs_mod->sops;
1049         if (data && data->bsize)
1050                 sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1051
1052         if (server->nfs_client->rpc_ops->version != 2) {
1053                 /* The VFS shouldn't apply the umask to mode bits. We will do
1054                  * so ourselves when necessary.
1055                  */
1056                 sb->s_flags |= SB_POSIXACL;
1057                 sb->s_time_gran = 1;
1058                 sb->s_export_op = &nfs_export_ops;
1059         } else
1060                 sb->s_time_gran = 1000;
1061
1062         if (server->nfs_client->rpc_ops->version != 4) {
1063                 sb->s_time_min = 0;
1064                 sb->s_time_max = U32_MAX;
1065         } else {
1066                 sb->s_time_min = S64_MIN;
1067                 sb->s_time_max = S64_MAX;
1068         }
1069
1070         sb->s_magic = NFS_SUPER_MAGIC;
1071
1072         /* We probably want something more informative here */
1073         snprintf(sb->s_id, sizeof(sb->s_id),
1074                  "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1075
1076         if (sb->s_blocksize == 0)
1077                 sb->s_blocksize = nfs_block_bits(server->wsize,
1078                                                  &sb->s_blocksize_bits);
1079
1080         nfs_super_set_maxbytes(sb, server->maxfilesize);
1081 }
1082
1083 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1084 {
1085         const struct nfs_server *a = s->s_fs_info;
1086         const struct rpc_clnt *clnt_a = a->client;
1087         const struct rpc_clnt *clnt_b = b->client;
1088
1089         if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1090                 goto Ebusy;
1091         if (a->nfs_client != b->nfs_client)
1092                 goto Ebusy;
1093         if ((a->flags ^ b->flags) & NFS_MOUNT_CMP_FLAGMASK)
1094                 goto Ebusy;
1095         if (a->wsize != b->wsize)
1096                 goto Ebusy;
1097         if (a->rsize != b->rsize)
1098                 goto Ebusy;
1099         if (a->acregmin != b->acregmin)
1100                 goto Ebusy;
1101         if (a->acregmax != b->acregmax)
1102                 goto Ebusy;
1103         if (a->acdirmin != b->acdirmin)
1104                 goto Ebusy;
1105         if (a->acdirmax != b->acdirmax)
1106                 goto Ebusy;
1107         if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1108                 goto Ebusy;
1109         return 1;
1110 Ebusy:
1111         return 0;
1112 }
1113
1114 struct nfs_sb_mountdata {
1115         struct nfs_server *server;
1116         int mntflags;
1117 };
1118
1119 static int nfs_set_super(struct super_block *s, void *data)
1120 {
1121         struct nfs_sb_mountdata *sb_mntdata = data;
1122         struct nfs_server *server = sb_mntdata->server;
1123         int ret;
1124
1125         s->s_flags = sb_mntdata->mntflags;
1126         s->s_fs_info = server;
1127         s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
1128         ret = set_anon_super(s, server);
1129         if (ret == 0)
1130                 server->s_dev = s->s_dev;
1131         return ret;
1132 }
1133
1134 static int nfs_compare_super_address(struct nfs_server *server1,
1135                                      struct nfs_server *server2)
1136 {
1137         struct sockaddr *sap1, *sap2;
1138         struct rpc_xprt *xprt1 = server1->client->cl_xprt;
1139         struct rpc_xprt *xprt2 = server2->client->cl_xprt;
1140
1141         if (!net_eq(xprt1->xprt_net, xprt2->xprt_net))
1142                 return 0;
1143
1144         sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1145         sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1146
1147         if (sap1->sa_family != sap2->sa_family)
1148                 return 0;
1149
1150         switch (sap1->sa_family) {
1151         case AF_INET: {
1152                 struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1153                 struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1154                 if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1155                         return 0;
1156                 if (sin1->sin_port != sin2->sin_port)
1157                         return 0;
1158                 break;
1159         }
1160         case AF_INET6: {
1161                 struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1162                 struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1163                 if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1164                         return 0;
1165                 if (sin1->sin6_port != sin2->sin6_port)
1166                         return 0;
1167                 break;
1168         }
1169         default:
1170                 return 0;
1171         }
1172
1173         return 1;
1174 }
1175
1176 static int nfs_compare_userns(const struct nfs_server *old,
1177                 const struct nfs_server *new)
1178 {
1179         const struct user_namespace *oldns = &init_user_ns;
1180         const struct user_namespace *newns = &init_user_ns;
1181
1182         if (old->client && old->client->cl_cred)
1183                 oldns = old->client->cl_cred->user_ns;
1184         if (new->client && new->client->cl_cred)
1185                 newns = new->client->cl_cred->user_ns;
1186         if (oldns != newns)
1187                 return 0;
1188         return 1;
1189 }
1190
1191 static int nfs_compare_super(struct super_block *sb, void *data)
1192 {
1193         struct nfs_sb_mountdata *sb_mntdata = data;
1194         struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1195         int mntflags = sb_mntdata->mntflags;
1196
1197         if (!nfs_compare_super_address(old, server))
1198                 return 0;
1199         /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1200         if (old->flags & NFS_MOUNT_UNSHARED)
1201                 return 0;
1202         if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1203                 return 0;
1204         if (!nfs_compare_userns(old, server))
1205                 return 0;
1206         return nfs_compare_mount_options(sb, server, mntflags);
1207 }
1208
1209 #ifdef CONFIG_NFS_FSCACHE
1210 static void nfs_get_cache_cookie(struct super_block *sb,
1211                                  struct nfs_parsed_mount_data *parsed,
1212                                  struct nfs_clone_mount *cloned)
1213 {
1214         struct nfs_server *nfss = NFS_SB(sb);
1215         char *uniq = NULL;
1216         int ulen = 0;
1217
1218         nfss->fscache_key = NULL;
1219         nfss->fscache = NULL;
1220
1221         if (parsed) {
1222                 if (!(parsed->options & NFS_OPTION_FSCACHE))
1223                         return;
1224                 if (parsed->fscache_uniq) {
1225                         uniq = parsed->fscache_uniq;
1226                         ulen = strlen(parsed->fscache_uniq);
1227                 }
1228         } else if (cloned) {
1229                 struct nfs_server *mnt_s = NFS_SB(cloned->sb);
1230                 if (!(mnt_s->options & NFS_OPTION_FSCACHE))
1231                         return;
1232                 if (mnt_s->fscache_key) {
1233                         uniq = mnt_s->fscache_key->key.uniquifier;
1234                         ulen = mnt_s->fscache_key->key.uniq_len;
1235                 }
1236         } else
1237                 return;
1238
1239         nfs_fscache_get_super_cookie(sb, uniq, ulen);
1240 }
1241 #else
1242 static void nfs_get_cache_cookie(struct super_block *sb,
1243                                  struct nfs_parsed_mount_data *parsed,
1244                                  struct nfs_clone_mount *cloned)
1245 {
1246 }
1247 #endif
1248
1249 static void nfs_set_readahead(struct backing_dev_info *bdi,
1250                               unsigned long iomax_pages)
1251 {
1252         bdi->ra_pages = VM_READAHEAD_PAGES;
1253         bdi->io_pages = iomax_pages;
1254 }
1255
1256 static struct dentry *nfs_fs_mount_common(int flags, const char *dev_name,
1257                                    struct nfs_mount_info *mount_info)
1258 {
1259         struct super_block *s;
1260         struct dentry *mntroot = ERR_PTR(-ENOMEM);
1261         int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1262         struct nfs_server *server = mount_info->server;
1263         unsigned long kflags = 0, kflags_out = 0;
1264         struct nfs_sb_mountdata sb_mntdata = {
1265                 .mntflags = flags,
1266                 .server = server,
1267         };
1268         int error;
1269
1270         mount_info->server = NULL;
1271         if (IS_ERR(server))
1272                 return ERR_CAST(server);
1273
1274         if (server->flags & NFS_MOUNT_UNSHARED)
1275                 compare_super = NULL;
1276
1277         /* -o noac implies -o sync */
1278         if (server->flags & NFS_MOUNT_NOAC)
1279                 sb_mntdata.mntflags |= SB_SYNCHRONOUS;
1280
1281         if (mount_info->cloned != NULL && mount_info->cloned->sb != NULL)
1282                 if (mount_info->cloned->sb->s_flags & SB_SYNCHRONOUS)
1283                         sb_mntdata.mntflags |= SB_SYNCHRONOUS;
1284
1285         /* Get a superblock - note that we may end up sharing one that already exists */
1286         s = sget(mount_info->nfs_mod->nfs_fs, compare_super, nfs_set_super,
1287                  flags, &sb_mntdata);
1288         if (IS_ERR(s)) {
1289                 mntroot = ERR_CAST(s);
1290                 goto out_err_nosb;
1291         }
1292
1293         if (s->s_fs_info != server) {
1294                 nfs_free_server(server);
1295                 server = NULL;
1296         } else {
1297                 error = super_setup_bdi_name(s, "%u:%u", MAJOR(server->s_dev),
1298                                              MINOR(server->s_dev));
1299                 if (error) {
1300                         mntroot = ERR_PTR(error);
1301                         goto error_splat_super;
1302                 }
1303                 nfs_set_readahead(s->s_bdi, server->rpages);
1304                 server->super = s;
1305         }
1306
1307         if (!s->s_root) {
1308                 unsigned bsize = mount_info->inherited_bsize;
1309                 /* initial superblock/root creation */
1310                 nfs_fill_super(s, mount_info);
1311                 if (bsize) {
1312                         s->s_blocksize_bits = bsize;
1313                         s->s_blocksize = 1U << bsize;
1314                 }
1315                 nfs_get_cache_cookie(s, mount_info->parsed, mount_info->cloned);
1316                 if (!(server->flags & NFS_MOUNT_UNSHARED))
1317                         s->s_iflags |= SB_I_MULTIROOT;
1318         }
1319
1320         mntroot = nfs_get_root(s, mount_info->mntfh, dev_name);
1321         if (IS_ERR(mntroot))
1322                 goto error_splat_super;
1323
1324
1325         if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL)
1326                 kflags |= SECURITY_LSM_NATIVE_LABELS;
1327         if (mount_info->cloned) {
1328                 if (d_inode(mntroot)->i_fop != &nfs_dir_operations) {
1329                         error = -ESTALE;
1330                         goto error_splat_root;
1331                 }
1332                 /* clone any lsm security options from the parent to the new sb */
1333                 error = security_sb_clone_mnt_opts(mount_info->cloned->sb, s, kflags,
1334                                 &kflags_out);
1335         } else {
1336                 error = security_sb_set_mnt_opts(s, mount_info->parsed->lsm_opts,
1337                                                         kflags, &kflags_out);
1338         }
1339         if (error)
1340                 goto error_splat_root;
1341         if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL &&
1342                 !(kflags_out & SECURITY_LSM_NATIVE_LABELS))
1343                 NFS_SB(s)->caps &= ~NFS_CAP_SECURITY_LABEL;
1344         if (error)
1345                 goto error_splat_root;
1346
1347         s->s_flags |= SB_ACTIVE;
1348
1349 out:
1350         return mntroot;
1351
1352 out_err_nosb:
1353         nfs_free_server(server);
1354         goto out;
1355
1356 error_splat_root:
1357         dput(mntroot);
1358         mntroot = ERR_PTR(error);
1359 error_splat_super:
1360         deactivate_locked_super(s);
1361         goto out;
1362 }
1363
1364 struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
1365         int flags, const char *dev_name, void *raw_data)
1366 {
1367         struct nfs_mount_info mount_info = {
1368         };
1369         struct dentry *mntroot = ERR_PTR(-ENOMEM);
1370         struct nfs_subversion *nfs_mod;
1371         int error;
1372
1373         mount_info.parsed = nfs_alloc_parsed_mount_data();
1374         mount_info.mntfh = nfs_alloc_fhandle();
1375         if (mount_info.parsed == NULL || mount_info.mntfh == NULL)
1376                 goto out;
1377
1378         /* Validate the mount data */
1379         error = nfs_validate_mount_data(fs_type, raw_data, mount_info.parsed, mount_info.mntfh, dev_name);
1380         if (error == NFS_TEXT_DATA)
1381                 error = nfs_validate_text_mount_data(raw_data, mount_info.parsed, dev_name);
1382         if (error < 0) {
1383                 mntroot = ERR_PTR(error);
1384                 goto out;
1385         }
1386
1387         nfs_mod = get_nfs_version(mount_info.parsed->version);
1388         if (IS_ERR(nfs_mod)) {
1389                 mntroot = ERR_CAST(nfs_mod);
1390                 goto out;
1391         }
1392         mount_info.nfs_mod = nfs_mod;
1393
1394         mntroot = nfs_mod->rpc_ops->try_mount(flags, dev_name, &mount_info);
1395
1396         put_nfs_version(nfs_mod);
1397 out:
1398         nfs_free_parsed_mount_data(mount_info.parsed);
1399         nfs_free_fhandle(mount_info.mntfh);
1400         return mntroot;
1401 }
1402 EXPORT_SYMBOL_GPL(nfs_fs_mount);
1403
1404 /*
1405  * Destroy an NFS2/3 superblock
1406  */
1407 void nfs_kill_super(struct super_block *s)
1408 {
1409         struct nfs_server *server = NFS_SB(s);
1410         dev_t dev = s->s_dev;
1411
1412         generic_shutdown_super(s);
1413
1414         nfs_fscache_release_super_cookie(s);
1415
1416         nfs_free_server(server);
1417         free_anon_bdev(dev);
1418 }
1419 EXPORT_SYMBOL_GPL(nfs_kill_super);
1420
1421 /*
1422  * Internal use only: mount_info is already set up by caller.
1423  * Used for mountpoint crossings and for nfs4 root.
1424  */
1425 static struct dentry *
1426 nfs_prepared_mount(struct file_system_type *fs_type, int flags,
1427                    const char *dev_name, void *raw_data)
1428 {
1429         return nfs_fs_mount_common(flags, dev_name, raw_data);
1430 }
1431
1432 #if IS_ENABLED(CONFIG_NFS_V4)
1433
1434 /*
1435  * NFS v4 module parameters need to stay in the
1436  * NFS client for backwards compatibility
1437  */
1438 unsigned int nfs_callback_set_tcpport;
1439 unsigned short nfs_callback_nr_threads;
1440 /* Default cache timeout is 10 minutes */
1441 unsigned int nfs_idmap_cache_timeout = 600;
1442 /* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
1443 bool nfs4_disable_idmapping = true;
1444 unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
1445 unsigned short max_session_cb_slots = NFS4_DEF_CB_SLOT_TABLE_SIZE;
1446 unsigned short send_implementation_id = 1;
1447 char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
1448 bool recover_lost_locks = false;
1449
1450 EXPORT_SYMBOL_GPL(nfs_callback_nr_threads);
1451 EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
1452 EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
1453 EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
1454 EXPORT_SYMBOL_GPL(max_session_slots);
1455 EXPORT_SYMBOL_GPL(max_session_cb_slots);
1456 EXPORT_SYMBOL_GPL(send_implementation_id);
1457 EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
1458 EXPORT_SYMBOL_GPL(recover_lost_locks);
1459
1460 #define NFS_CALLBACK_MAXPORTNR (65535U)
1461
1462 static int param_set_portnr(const char *val, const struct kernel_param *kp)
1463 {
1464         unsigned long num;
1465         int ret;
1466
1467         if (!val)
1468                 return -EINVAL;
1469         ret = kstrtoul(val, 0, &num);
1470         if (ret || num > NFS_CALLBACK_MAXPORTNR)
1471                 return -EINVAL;
1472         *((unsigned int *)kp->arg) = num;
1473         return 0;
1474 }
1475 static const struct kernel_param_ops param_ops_portnr = {
1476         .set = param_set_portnr,
1477         .get = param_get_uint,
1478 };
1479 #define param_check_portnr(name, p) __param_check(name, p, unsigned int);
1480
1481 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1482 module_param_named(callback_nr_threads, nfs_callback_nr_threads, ushort, 0644);
1483 MODULE_PARM_DESC(callback_nr_threads, "Number of threads that will be "
1484                 "assigned to the NFSv4 callback channels.");
1485 module_param(nfs_idmap_cache_timeout, int, 0644);
1486 module_param(nfs4_disable_idmapping, bool, 0644);
1487 module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
1488                         NFS4_CLIENT_ID_UNIQ_LEN, 0600);
1489 MODULE_PARM_DESC(nfs4_disable_idmapping,
1490                 "Turn off NFSv4 idmapping when using 'sec=sys'");
1491 module_param(max_session_slots, ushort, 0644);
1492 MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
1493                 "requests the client will negotiate");
1494 module_param(max_session_cb_slots, ushort, 0644);
1495 MODULE_PARM_DESC(max_session_cb_slots, "Maximum number of parallel NFSv4.1 "
1496                 "callbacks the client will process for a given server");
1497 module_param(send_implementation_id, ushort, 0644);
1498 MODULE_PARM_DESC(send_implementation_id,
1499                 "Send implementation ID with NFSv4.1 exchange_id");
1500 MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
1501
1502 module_param(recover_lost_locks, bool, 0644);
1503 MODULE_PARM_DESC(recover_lost_locks,
1504                  "If the server reports that a lock might be lost, "
1505                  "try to recover it risking data corruption.");
1506
1507
1508 #endif /* CONFIG_NFS_V4 */