fs/nfsd/nfssvc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Central processing for nfsd.
   4  *
   5  * Authors:     Olaf Kirch (okir@monad.swb.de)
   6  *
   7  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   8  */
   9
  10 #include <linux/sched/signal.h>
  11 #include <linux/freezer.h>
  12 #include <linux/module.h>
  13 #include <linux/fs_struct.h>
  14 #include <linux/swap.h>
  15
  16 #include <linux/sunrpc/stats.h>
  17 #include <linux/sunrpc/svcsock.h>
  18 #include <linux/sunrpc/svc_xprt.h>
  19 #include <linux/lockd/bind.h>
  20 #include <linux/nfsacl.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/inetdevice.h>
  23 #include <net/addrconf.h>
  24 #include <net/ipv6.h>
  25 #include <net/net_namespace.h>
  26 #include "nfsd.h"
  27 #include "cache.h"
  28 #include "vfs.h"
  29 #include "netns.h"
  30
  31 #define NFSDDBG_FACILITY        NFSDDBG_SVC
  32
  33 extern struct svc_program       nfsd_program;
  34 static int                      nfsd(void *vrqstp);
  35
  36 /*
  37  * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members
  38  * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
  39  * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
  40  *
  41  * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a
  42  * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
  43  * of nfsd threads must exist and each must listed in ->sp_all_threads in each
  44  * entry of ->sv_pools[].
  45  *
  46  * Transitions of the thread count between zero and non-zero are of particular
  47  * interest since the svc_serv needs to be created and initialized at that
  48  * point, or freed.
  49  *
  50  * Finally, the nfsd_mutex also protects some of the global variables that are
  51  * accessed when nfsd starts and that are settable via the write_* routines in
  52  * nfsctl.c. In particular:
  53  *
  54  *      user_recovery_dirname
  55  *      user_lease_time
  56  *      nfsd_versions
  57  */
  58 DEFINE_MUTEX(nfsd_mutex);
  59
  60 /*
  61  * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
  62  * nfsd_drc_max_pages limits the total amount of memory available for
  63  * version 4.1 DRC caches.
  64  * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
  65  */
  66 spinlock_t      nfsd_drc_lock;
  67 unsigned long   nfsd_drc_max_mem;
  68 unsigned long   nfsd_drc_mem_used;
  69
  70 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  71 static struct svc_stat  nfsd_acl_svcstats;
  72 static const struct svc_version *nfsd_acl_version[] = {
  73         [2] = &nfsd_acl_version2,
  74         [3] = &nfsd_acl_version3,
  75 };
  76
  77 #define NFSD_ACL_MINVERS            2
  78 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  79 static const struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  80
  81 static struct svc_program       nfsd_acl_program = {
  82         .pg_prog                = NFS_ACL_PROGRAM,
  83         .pg_nvers               = NFSD_ACL_NRVERS,
  84         .pg_vers                = nfsd_acl_versions,
  85         .pg_name                = "nfsacl",
  86         .pg_class               = "nfsd",
  87         .pg_stats               = &nfsd_acl_svcstats,
  88         .pg_authenticate        = &svc_set_client,
  89 };
  90
  91 static struct svc_stat  nfsd_acl_svcstats = {
  92         .program        = &nfsd_acl_program,
  93 };
  94 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  95
  96 static const struct svc_version *nfsd_version[] = {
  97         [2] = &nfsd_version2,
  98 #if defined(CONFIG_NFSD_V3)
  99         [3] = &nfsd_version3,
 100 #endif
 101 #if defined(CONFIG_NFSD_V4)
 102         [4] = &nfsd_version4,
 103 #endif
 104 };
 105
 106 #define NFSD_MINVERS            2
 107 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
 108 static const struct svc_version *nfsd_versions[NFSD_NRVERS];
 109
 110 struct svc_program              nfsd_program = {
 111 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 112         .pg_next                = &nfsd_acl_program,
 113 #endif
 114         .pg_prog                = NFS_PROGRAM,          /* program number */
 115         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 116         .pg_vers                = nfsd_versions,        /* version table */
 117         .pg_name                = "nfsd",               /* program name */
 118         .pg_class               = "nfsd",               /* authentication class */
 119         .pg_stats               = &nfsd_svcstats,       /* version table */
 120         .pg_authenticate        = &svc_set_client,      /* export authentication */
 121
 122 };
 123
 124 static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = {
 125         [0] = 1,
 126         [1] = 1,
 127         [2] = 1,
 128 };
 129
 130 int nfsd_vers(int vers, enum vers_op change)
 131 {
 132         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
 133                 return 0;
 134         switch(change) {
 135         case NFSD_SET:
 136                 nfsd_versions[vers] = nfsd_version[vers];
 137 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 138                 if (vers < NFSD_ACL_NRVERS)
 139                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
 140 #endif
 141                 break;
 142         case NFSD_CLEAR:
 143                 nfsd_versions[vers] = NULL;
 144 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 145                 if (vers < NFSD_ACL_NRVERS)
 146                         nfsd_acl_versions[vers] = NULL;
 147 #endif
 148                 break;
 149         case NFSD_TEST:
 150                 return nfsd_versions[vers] != NULL;
 151         case NFSD_AVAIL:
 152                 return nfsd_version[vers] != NULL;
 153         }
 154         return 0;
 155 }
 156
 157 static void
 158 nfsd_adjust_nfsd_versions4(void)
 159 {
 160         unsigned i;
 161
 162         for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) {
 163                 if (nfsd_supported_minorversions[i])
 164                         return;
 165         }
 166         nfsd_vers(4, NFSD_CLEAR);
 167 }
 168
 169 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 170 {
 171         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
 172             change != NFSD_AVAIL)
 173                 return -1;
 174         switch(change) {
 175         case NFSD_SET:
 176                 nfsd_supported_minorversions[minorversion] = true;
 177                 nfsd_vers(4, NFSD_SET);
 178                 break;
 179         case NFSD_CLEAR:
 180                 nfsd_supported_minorversions[minorversion] = false;
 181                 nfsd_adjust_nfsd_versions4();
 182                 break;
 183         case NFSD_TEST:
 184                 return nfsd_supported_minorversions[minorversion];
 185         case NFSD_AVAIL:
 186                 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
 187         }
 188         return 0;
 189 }
 190
 191 /*
 192  * Maximum number of nfsd processes
 193  */
 194 #define NFSD_MAXSERVS           8192
 195
 196 int nfsd_nrthreads(struct net *net)
 197 {
 198         int rv = 0;
 199         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 200
 201         mutex_lock(&nfsd_mutex);
 202         if (nn->nfsd_serv)
 203                 rv = nn->nfsd_serv->sv_nrthreads;
 204         mutex_unlock(&nfsd_mutex);
 205         return rv;
 206 }
 207
 208 static int nfsd_init_socks(struct net *net)
 209 {
 210         int error;
 211         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 212
 213         if (!list_empty(&nn->nfsd_serv->sv_permsocks))
 214                 return 0;
 215
 216         error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
 217                                         SVC_SOCK_DEFAULTS);
 218         if (error < 0)
 219                 return error;
 220
 221         error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
 222                                         SVC_SOCK_DEFAULTS);
 223         if (error < 0)
 224                 return error;
 225
 226         return 0;
 227 }
 228
 229 static int nfsd_users = 0;
 230
 231 static int nfsd_startup_generic(int nrservs)
 232 {
 233         int ret;
 234
 235         if (nfsd_users++)
 236                 return 0;
 237
 238         /*
 239          * Readahead param cache - will no-op if it already exists.
 240          * (Note therefore results will be suboptimal if number of
 241          * threads is modified after nfsd start.)
 242          */
 243         ret = nfsd_racache_init(2*nrservs);
 244         if (ret)
 245                 goto dec_users;
 246
 247         ret = nfs4_state_start();
 248         if (ret)
 249                 goto out_racache;
 250         return 0;
 251
 252 out_racache:
 253         nfsd_racache_shutdown();
 254 dec_users:
 255         nfsd_users--;
 256         return ret;
 257 }
 258
 259 static void nfsd_shutdown_generic(void)
 260 {
 261         if (--nfsd_users)
 262                 return;
 263
 264         nfs4_state_shutdown();
 265         nfsd_racache_shutdown();
 266 }
 267
 268 static bool nfsd_needs_lockd(void)
 269 {
 270 #if defined(CONFIG_NFSD_V3)
 271         return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
 272 #else
 273         return (nfsd_versions[2] != NULL);
 274 #endif
 275 }
 276
 277 static int nfsd_startup_net(int nrservs, struct net *net)
 278 {
 279         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 280         int ret;
 281
 282         if (nn->nfsd_net_up)
 283                 return 0;
 284
 285         ret = nfsd_startup_generic(nrservs);
 286         if (ret)
 287                 return ret;
 288         ret = nfsd_init_socks(net);
 289         if (ret)
 290                 goto out_socks;
 291
 292         if (nfsd_needs_lockd() && !nn->lockd_up) {
 293                 ret = lockd_up(net);
 294                 if (ret)
 295                         goto out_socks;
 296                 nn->lockd_up = 1;
 297         }
 298
 299         ret = nfs4_state_start_net(net);
 300         if (ret)
 301                 goto out_lockd;
 302
 303         nn->nfsd_net_up = true;
 304         return 0;
 305
 306 out_lockd:
 307         if (nn->lockd_up) {
 308                 lockd_down(net);
 309                 nn->lockd_up = 0;
 310         }
 311 out_socks:
 312         nfsd_shutdown_generic();
 313         return ret;
 314 }
 315
 316 static void nfsd_shutdown_net(struct net *net)
 317 {
 318         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 319
 320         nfs4_state_shutdown_net(net);
 321         if (nn->lockd_up) {
 322                 lockd_down(net);
 323                 nn->lockd_up = 0;
 324         }
 325         nn->nfsd_net_up = false;
 326         nfsd_shutdown_generic();
 327 }
 328
 329 static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
 330         void *ptr)
 331 {
 332         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
 333         struct net_device *dev = ifa->ifa_dev->dev;
 334         struct net *net = dev_net(dev);
 335         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 336         struct sockaddr_in sin;
 337
 338         if ((event != NETDEV_DOWN) ||
 339             !atomic_inc_not_zero(&nn->ntf_refcnt))
 340                 goto out;
 341
 342         if (nn->nfsd_serv) {
 343                 dprintk("nfsd_inetaddr_event: removed %pI4\n", &ifa->ifa_local);
 344                 sin.sin_family = AF_INET;
 345                 sin.sin_addr.s_addr = ifa->ifa_local;
 346                 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin);
 347         }
 348         atomic_dec(&nn->ntf_refcnt);
 349         wake_up(&nn->ntf_wq);
 350
 351 out:
 352         return NOTIFY_DONE;
 353 }
 354
 355 static struct notifier_block nfsd_inetaddr_notifier = {
 356         .notifier_call = nfsd_inetaddr_event,
 357 };
 358
 359 #if IS_ENABLED(CONFIG_IPV6)
 360 static int nfsd_inet6addr_event(struct notifier_block *this,
 361         unsigned long event, void *ptr)
 362 {
 363         struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
 364         struct net_device *dev = ifa->idev->dev;
 365         struct net *net = dev_net(dev);
 366         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 367         struct sockaddr_in6 sin6;
 368
 369         if ((event != NETDEV_DOWN) ||
 370             !atomic_inc_not_zero(&nn->ntf_refcnt))
 371                 goto out;
 372
 373         if (nn->nfsd_serv) {
 374                 dprintk("nfsd_inet6addr_event: removed %pI6\n", &ifa->addr);
 375                 sin6.sin6_family = AF_INET6;
 376                 sin6.sin6_addr = ifa->addr;
 377                 if (ipv6_addr_type(&sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
 378                         sin6.sin6_scope_id = ifa->idev->dev->ifindex;
 379                 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6);
 380         }
 381         atomic_dec(&nn->ntf_refcnt);
 382         wake_up(&nn->ntf_wq);
 383 out:
 384         return NOTIFY_DONE;
 385 }
 386
 387 static struct notifier_block nfsd_inet6addr_notifier = {
 388         .notifier_call = nfsd_inet6addr_event,
 389 };
 390 #endif
 391
 392 /* Only used under nfsd_mutex, so this atomic may be overkill: */
 393 static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
 394
 395 static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
 396 {
 397         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 398
 399         atomic_dec(&nn->ntf_refcnt);
 400         /* check if the notifier still has clients */
 401         if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
 402                 unregister_inetaddr_notifier(&nfsd_inetaddr_notifier);
 403 #if IS_ENABLED(CONFIG_IPV6)
 404                 unregister_inet6addr_notifier(&nfsd_inet6addr_notifier);
 405 #endif
 406         }
 407         wait_event(nn->ntf_wq, atomic_read(&nn->ntf_refcnt) == 0);
 408
 409         /*
 410          * write_ports can create the server without actually starting
 411          * any threads--if we get shut down before any threads are
 412          * started, then nfsd_last_thread will be run before any of this
 413          * other initialization has been done except the rpcb information.
 414          */
 415         svc_rpcb_cleanup(serv, net);
 416         if (!nn->nfsd_net_up)
 417                 return;
 418
 419         nfsd_shutdown_net(net);
 420         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
 421                             "cache\n");
 422         nfsd_export_flush(net);
 423 }
 424
 425 void nfsd_reset_versions(void)
 426 {
 427         int i;
 428
 429         for (i = 0; i < NFSD_NRVERS; i++)
 430                 if (nfsd_vers(i, NFSD_TEST))
 431                         return;
 432
 433         for (i = 0; i < NFSD_NRVERS; i++)
 434                 if (i != 4)
 435                         nfsd_vers(i, NFSD_SET);
 436                 else {
 437                         int minor = 0;
 438                         while (nfsd_minorversion(minor, NFSD_SET) >= 0)
 439                                 minor++;
 440                 }
 441 }
 442
 443 /*
 444  * Each session guarantees a negotiated per slot memory cache for replies
 445  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 446  * NFSv4.1 server might want to use more memory for a DRC than a machine
 447  * with mutiple services.
 448  *
 449  * Impose a hard limit on the number of pages for the DRC which varies
 450  * according to the machines free pages. This is of course only a default.
 451  *
 452  * For now this is a #defined shift which could be under admin control
 453  * in the future.
 454  */
 455 static void set_max_drc(void)
 456 {
 457         #define NFSD_DRC_SIZE_SHIFT     7
 458         nfsd_drc_max_mem = (nr_free_buffer_pages()
 459                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
 460         nfsd_drc_mem_used = 0;
 461         spin_lock_init(&nfsd_drc_lock);
 462         dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
 463 }
 464
 465 static int nfsd_get_default_max_blksize(void)
 466 {
 467         struct sysinfo i;
 468         unsigned long long target;
 469         unsigned long ret;
 470
 471         si_meminfo(&i);
 472         target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
 473         /*
 474          * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
 475          * machines, but only uses 32K on 128M machines.  Bottom out at
 476          * 8K on 32M and smaller.  Of course, this is only a default.
 477          */
 478         target >>= 12;
 479
 480         ret = NFSSVC_MAXBLKSIZE;
 481         while (ret > target && ret >= 8*1024*2)
 482                 ret /= 2;
 483         return ret;
 484 }
 485
 486 static const struct svc_serv_ops nfsd_thread_sv_ops = {
 487         .svo_shutdown           = nfsd_last_thread,
 488         .svo_function           = nfsd,
 489         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 490         .svo_setup              = svc_set_num_threads,
 491         .svo_module             = THIS_MODULE,
 492 };
 493
 494 int nfsd_create_serv(struct net *net)
 495 {
 496         int error;
 497         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 498
 499         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 500         if (nn->nfsd_serv) {
 501                 svc_get(nn->nfsd_serv);
 502                 return 0;
 503         }
 504         if (nfsd_max_blksize == 0)
 505                 nfsd_max_blksize = nfsd_get_default_max_blksize();
 506         nfsd_reset_versions();
 507         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
 508                                                 &nfsd_thread_sv_ops);
 509         if (nn->nfsd_serv == NULL)
 510                 return -ENOMEM;
 511
 512         nn->nfsd_serv->sv_maxconn = nn->max_connections;
 513         error = svc_bind(nn->nfsd_serv, net);
 514         if (error < 0) {
 515                 svc_destroy(nn->nfsd_serv);
 516                 return error;
 517         }
 518
 519         set_max_drc();
 520         /* check if the notifier is already set */
 521         if (atomic_inc_return(&nfsd_notifier_refcount) == 1) {
 522                 register_inetaddr_notifier(&nfsd_inetaddr_notifier);
 523 #if IS_ENABLED(CONFIG_IPV6)
 524                 register_inet6addr_notifier(&nfsd_inet6addr_notifier);
 525 #endif
 526         }
 527         atomic_inc(&nn->ntf_refcnt);
 528         ktime_get_real_ts64(&nn->nfssvc_boot); /* record boot time */
 529         return 0;
 530 }
 531
 532 int nfsd_nrpools(struct net *net)
 533 {
 534         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 535
 536         if (nn->nfsd_serv == NULL)
 537                 return 0;
 538         else
 539                 return nn->nfsd_serv->sv_nrpools;
 540 }
 541
 542 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
 543 {
 544         int i = 0;
 545         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 546
 547         if (nn->nfsd_serv != NULL) {
 548                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
 549                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
 550         }
 551
 552         return 0;
 553 }
 554
 555 void nfsd_destroy(struct net *net)
 556 {
 557         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 558         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
 559
 560         if (destroy)
 561                 svc_shutdown_net(nn->nfsd_serv, net);
 562         svc_destroy(nn->nfsd_serv);
 563         if (destroy)
 564                 nn->nfsd_serv = NULL;
 565 }
 566
 567 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 568 {
 569         int i = 0;
 570         int tot = 0;
 571         int err = 0;
 572         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 573
 574         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 575
 576         if (nn->nfsd_serv == NULL || n <= 0)
 577                 return 0;
 578
 579         if (n > nn->nfsd_serv->sv_nrpools)
 580                 n = nn->nfsd_serv->sv_nrpools;
 581
 582         /* enforce a global maximum number of threads */
 583         tot = 0;
 584         for (i = 0; i < n; i++) {
 585                 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
 586                 tot += nthreads[i];
 587         }
 588         if (tot > NFSD_MAXSERVS) {
 589                 /* total too large: scale down requested numbers */
 590                 for (i = 0; i < n && tot > 0; i++) {
 591                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 592                         tot -= (nthreads[i] - new);
 593                         nthreads[i] = new;
 594                 }
 595                 for (i = 0; i < n && tot > 0; i++) {
 596                         nthreads[i]--;
 597                         tot--;
 598                 }
 599         }
 600
 601         /*
 602          * There must always be a thread in pool 0; the admin
 603          * can't shut down NFS completely using pool_threads.
 604          */
 605         if (nthreads[0] == 0)
 606                 nthreads[0] = 1;
 607
 608         /* apply the new numbers */
 609         svc_get(nn->nfsd_serv);
 610         for (i = 0; i < n; i++) {
 611                 err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
 612                                 &nn->nfsd_serv->sv_pools[i], nthreads[i]);
 613                 if (err)
 614                         break;
 615         }
 616         nfsd_destroy(net);
 617         return err;
 618 }
 619
 620 /*
 621  * Adjust the number of threads and return the new number of threads.
 622  * This is also the function that starts the server if necessary, if
 623  * this is the first time nrservs is nonzero.
 624  */
 625 int
 626 nfsd_svc(int nrservs, struct net *net)
 627 {
 628         int     error;
 629         bool    nfsd_up_before;
 630         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 631
 632         mutex_lock(&nfsd_mutex);
 633         dprintk("nfsd: creating service\n");
 634
 635         nrservs = max(nrservs, 0);
 636         nrservs = min(nrservs, NFSD_MAXSERVS);
 637         error = 0;
 638
 639         if (nrservs == 0 && nn->nfsd_serv == NULL)
 640                 goto out;
 641
 642         error = nfsd_create_serv(net);
 643         if (error)
 644                 goto out;
 645
 646         nfsd_up_before = nn->nfsd_net_up;
 647
 648         error = nfsd_startup_net(nrservs, net);
 649         if (error)
 650                 goto out_destroy;
 651         error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
 652                         NULL, nrservs);
 653         if (error)
 654                 goto out_shutdown;
 655         /* We are holding a reference to nn->nfsd_serv which
 656          * we don't want to count in the return value,
 657          * so subtract 1
 658          */
 659         error = nn->nfsd_serv->sv_nrthreads - 1;
 660 out_shutdown:
 661         if (error < 0 && !nfsd_up_before)
 662                 nfsd_shutdown_net(net);
 663 out_destroy:
 664         nfsd_destroy(net);              /* Release server */
 665 out:
 666         mutex_unlock(&nfsd_mutex);
 667         return error;
 668 }
 669
 670
 671 /*
 672  * This is the NFS server kernel thread
 673  */
 674 static int
 675 nfsd(void *vrqstp)
 676 {
 677         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 678         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
 679         struct net *net = perm_sock->xpt_net;
 680         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 681         int err;
 682
 683         /* Lock module and set up kernel thread */
 684         mutex_lock(&nfsd_mutex);
 685
 686         /* At this point, the thread shares current->fs
 687          * with the init process. We need to create files with the
 688          * umask as defined by the client instead of init's umask. */
 689         if (unshare_fs_struct() < 0) {
 690                 printk("Unable to start nfsd thread: out of memory\n");
 691                 goto out;
 692         }
 693
 694         current->fs->umask = 0;
 695
 696         /*
 697          * thread is spawned with all signals set to SIG_IGN, re-enable
 698          * the ones that will bring down the thread
 699          */
 700         allow_signal(SIGKILL);
 701         allow_signal(SIGHUP);
 702         allow_signal(SIGINT);
 703         allow_signal(SIGQUIT);
 704
 705         nfsdstats.th_cnt++;
 706         mutex_unlock(&nfsd_mutex);
 707
 708         set_freezable();
 709
 710         /*
 711          * The main request loop
 712          */
 713         for (;;) {
 714                 /* Update sv_maxconn if it has changed */
 715                 rqstp->rq_server->sv_maxconn = nn->max_connections;
 716
 717                 /*
 718                  * Find a socket with data available and call its
 719                  * recvfrom routine.
 720                  */
 721                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 722                         ;
 723                 if (err == -EINTR)
 724                         break;
 725                 validate_process_creds();
 726                 svc_process(rqstp);
 727                 validate_process_creds();
 728         }
 729
 730         /* Clear signals before calling svc_exit_thread() */
 731         flush_signals(current);
 732
 733         mutex_lock(&nfsd_mutex);
 734         nfsdstats.th_cnt --;
 735
 736 out:
 737         rqstp->rq_server = NULL;
 738
 739         /* Release the thread */
 740         svc_exit_thread(rqstp);
 741
 742         nfsd_destroy(net);
 743
 744         /* Release module */
 745         mutex_unlock(&nfsd_mutex);
 746         module_put_and_exit(0);
 747         return 0;
 748 }
 749
 750 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 751 {
 752         if (nfserr == nfserr_jukebox && vers == 2)
 753                 return nfserr_dropit;
 754         if (nfserr == nfserr_wrongsec && vers < 4)
 755                 return nfserr_acces;
 756         return nfserr;
 757 }
 758
 759 /*
 760  * A write procedure can have a large argument, and a read procedure can
 761  * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
 762  * reply that can both be larger than a page.  The xdr code has taken
 763  * advantage of this assumption to be a sloppy about bounds checking in
 764  * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
 765  * problem, we enforce these assumptions here:
 766  */
 767 static bool nfs_request_too_big(struct svc_rqst *rqstp,
 768                                 const struct svc_procedure *proc)
 769 {
 770         /*
 771          * The ACL code has more careful bounds-checking and is not
 772          * susceptible to this problem:
 773          */
 774         if (rqstp->rq_prog != NFS_PROGRAM)
 775                 return false;
 776         /*
 777          * Ditto NFSv4 (which can in theory have argument and reply both
 778          * more than a page):
 779          */
 780         if (rqstp->rq_vers >= 4)
 781                 return false;
 782         /* The reply will be small, we're OK: */
 783         if (proc->pc_xdrressize > 0 &&
 784             proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
 785                 return false;
 786
 787         return rqstp->rq_arg.len > PAGE_SIZE;
 788 }
 789
 790 int
 791 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 792 {
 793         const struct svc_procedure *proc;
 794         __be32                  nfserr;
 795         __be32                  *nfserrp;
 796
 797         dprintk("nfsd_dispatch: vers %d proc %d\n",
 798                                 rqstp->rq_vers, rqstp->rq_proc);
 799         proc = rqstp->rq_procinfo;
 800
 801         if (nfs_request_too_big(rqstp, proc)) {
 802                 dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
 803                 *statp = rpc_garbage_args;
 804                 return 1;
 805         }
 806         /*
 807          * Give the xdr decoder a chance to change this if it wants
 808          * (necessary in the NFSv4.0 compound case)
 809          */
 810         rqstp->rq_cachetype = proc->pc_cachetype;
 811         /* Decode arguments */
 812         if (proc->pc_decode &&
 813             !proc->pc_decode(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base)) {
 814                 dprintk("nfsd: failed to decode arguments!\n");
 815                 *statp = rpc_garbage_args;
 816                 return 1;
 817         }
 818
 819         /* Check whether we have this call in the cache. */
 820         switch (nfsd_cache_lookup(rqstp)) {
 821         case RC_DROPIT:
 822                 return 0;
 823         case RC_REPLY:
 824                 return 1;
 825         case RC_DOIT:;
 826                 /* do it */
 827         }
 828
 829         /* need to grab the location to store the status, as
 830          * nfsv4 does some encoding while processing
 831          */
 832         nfserrp = rqstp->rq_res.head[0].iov_base
 833                 + rqstp->rq_res.head[0].iov_len;
 834         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 835
 836         /* Now call the procedure handler, and encode NFS status. */
 837         nfserr = proc->pc_func(rqstp);
 838         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 839         if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) {
 840                 dprintk("nfsd: Dropping request; may be revisited later\n");
 841                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 842                 return 0;
 843         }
 844
 845         if (rqstp->rq_proc != 0)
 846                 *nfserrp++ = nfserr;
 847
 848         /* Encode result.
 849          * For NFSv2, additional info is never returned in case of an error.
 850          */
 851         if (!(nfserr && rqstp->rq_vers == 2)) {
 852                 if (proc->pc_encode && !proc->pc_encode(rqstp, nfserrp)) {
 853                         /* Failed to encode result. Release cache entry */
 854                         dprintk("nfsd: failed to encode result!\n");
 855                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 856                         *statp = rpc_system_err;
 857                         return 1;
 858                 }
 859         }
 860
 861         /* Store reply in cache. */
 862         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
 863         return 1;
 864 }
 865
 866 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 867 {
 868         int ret;
 869         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
 870
 871         mutex_lock(&nfsd_mutex);
 872         if (nn->nfsd_serv == NULL) {
 873                 mutex_unlock(&nfsd_mutex);
 874                 return -ENODEV;
 875         }
 876         /* bump up the psudo refcount while traversing */
 877         svc_get(nn->nfsd_serv);
 878         ret = svc_pool_stats_open(nn->nfsd_serv, file);
 879         mutex_unlock(&nfsd_mutex);
 880         return ret;
 881 }
 882
 883 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 884 {
 885         int ret = seq_release(inode, file);
 886         struct net *net = inode->i_sb->s_fs_info;
 887
 888         mutex_lock(&nfsd_mutex);
 889         /* this function really, really should have been called svc_put() */
 890         nfsd_destroy(net);
 891         mutex_unlock(&nfsd_mutex);
 892         return ret;
 893 }