fs/nfsd/nfssvc.c

   1 /*
   2  * linux/fs/nfsd/nfssvc.c
   3  *
   4  * Central processing for nfsd.
   5  *
   6  * Authors:     Olaf Kirch (okir@monad.swb.de)
   7  *
   8  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/time.h>
  14 #include <linux/errno.h>
  15 #include <linux/nfs.h>
  16 #include <linux/in.h>
  17 #include <linux/uio.h>
  18 #include <linux/unistd.h>
  19 #include <linux/slab.h>
  20 #include <linux/smp.h>
  21 #include <linux/freezer.h>
  22 #include <linux/fs_struct.h>
  23 #include <linux/kthread.h>
  24 #include <linux/swap.h>
  25
  26 #include <linux/sunrpc/types.h>
  27 #include <linux/sunrpc/stats.h>
  28 #include <linux/sunrpc/svc.h>
  29 #include <linux/sunrpc/svcsock.h>
  30 #include <linux/sunrpc/cache.h>
  31 #include <linux/nfsd/nfsd.h>
  32 #include <linux/nfsd/stats.h>
  33 #include <linux/nfsd/cache.h>
  34 #include <linux/nfsd/syscall.h>
  35 #include <linux/lockd/bind.h>
  36 #include <linux/nfsacl.h>
  37 #include <linux/seq_file.h>
  38
  39 #define NFSDDBG_FACILITY        NFSDDBG_SVC
  40
  41 extern struct svc_program       nfsd_program;
  42 static int                      nfsd(void *vrqstp);
  43 struct timeval                  nfssvc_boot;
  44
  45 /*
  46  * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members
  47  * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
  48  * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
  49  *
  50  * If (out side the lock) nfsd_serv is non-NULL, then it must point to a
  51  * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
  52  * of nfsd threads must exist and each must listed in ->sp_all_threads in each
  53  * entry of ->sv_pools[].
  54  *
  55  * Transitions of the thread count between zero and non-zero are of particular
  56  * interest since the svc_serv needs to be created and initialized at that
  57  * point, or freed.
  58  *
  59  * Finally, the nfsd_mutex also protects some of the global variables that are
  60  * accessed when nfsd starts and that are settable via the write_* routines in
  61  * nfsctl.c. In particular:
  62  *
  63  *      user_recovery_dirname
  64  *      user_lease_time
  65  *      nfsd_versions
  66  */
  67 DEFINE_MUTEX(nfsd_mutex);
  68 struct svc_serv                 *nfsd_serv;
  69
  70 /*
  71  * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
  72  * nfsd_drc_max_pages limits the total amount of memory available for
  73  * version 4.1 DRC caches.
  74  * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
  75  */
  76 spinlock_t      nfsd_drc_lock;
  77 unsigned int    nfsd_drc_max_mem;
  78 unsigned int    nfsd_drc_mem_used;
  79
  80 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  81 static struct svc_stat  nfsd_acl_svcstats;
  82 static struct svc_version *     nfsd_acl_version[] = {
  83         [2] = &nfsd_acl_version2,
  84         [3] = &nfsd_acl_version3,
  85 };
  86
  87 #define NFSD_ACL_MINVERS            2
  88 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  89 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  90
  91 static struct svc_program       nfsd_acl_program = {
  92         .pg_prog                = NFS_ACL_PROGRAM,
  93         .pg_nvers               = NFSD_ACL_NRVERS,
  94         .pg_vers                = nfsd_acl_versions,
  95         .pg_name                = "nfsacl",
  96         .pg_class               = "nfsd",
  97         .pg_stats               = &nfsd_acl_svcstats,
  98         .pg_authenticate        = &svc_set_client,
  99 };
 100
 101 static struct svc_stat  nfsd_acl_svcstats = {
 102         .program        = &nfsd_acl_program,
 103 };
 104 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
 105
 106 static struct svc_version *     nfsd_version[] = {
 107         [2] = &nfsd_version2,
 108 #if defined(CONFIG_NFSD_V3)
 109         [3] = &nfsd_version3,
 110 #endif
 111 #if defined(CONFIG_NFSD_V4)
 112         [4] = &nfsd_version4,
 113 #endif
 114 };
 115
 116 #define NFSD_MINVERS            2
 117 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
 118 static struct svc_version *nfsd_versions[NFSD_NRVERS];
 119
 120 struct svc_program              nfsd_program = {
 121 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 122         .pg_next                = &nfsd_acl_program,
 123 #endif
 124         .pg_prog                = NFS_PROGRAM,          /* program number */
 125         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 126         .pg_vers                = nfsd_versions,        /* version table */
 127         .pg_name                = "nfsd",               /* program name */
 128         .pg_class               = "nfsd",               /* authentication class */
 129         .pg_stats               = &nfsd_svcstats,       /* version table */
 130         .pg_authenticate        = &svc_set_client,      /* export authentication */
 131
 132 };
 133
 134 u32 nfsd_supported_minorversion;
 135
 136 int nfsd_vers(int vers, enum vers_op change)
 137 {
 138         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
 139                 return -1;
 140         switch(change) {
 141         case NFSD_SET:
 142                 nfsd_versions[vers] = nfsd_version[vers];
 143 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 144                 if (vers < NFSD_ACL_NRVERS)
 145                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
 146 #endif
 147                 break;
 148         case NFSD_CLEAR:
 149                 nfsd_versions[vers] = NULL;
 150 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 151                 if (vers < NFSD_ACL_NRVERS)
 152                         nfsd_acl_versions[vers] = NULL;
 153 #endif
 154                 break;
 155         case NFSD_TEST:
 156                 return nfsd_versions[vers] != NULL;
 157         case NFSD_AVAIL:
 158                 return nfsd_version[vers] != NULL;
 159         }
 160         return 0;
 161 }
 162
 163 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 164 {
 165         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
 166                 return -1;
 167         switch(change) {
 168         case NFSD_SET:
 169                 nfsd_supported_minorversion = minorversion;
 170                 break;
 171         case NFSD_CLEAR:
 172                 if (minorversion == 0)
 173                         return -1;
 174                 nfsd_supported_minorversion = minorversion - 1;
 175                 break;
 176         case NFSD_TEST:
 177                 return minorversion <= nfsd_supported_minorversion;
 178         case NFSD_AVAIL:
 179                 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
 180         }
 181         return 0;
 182 }
 183
 184 /*
 185  * Maximum number of nfsd processes
 186  */
 187 #define NFSD_MAXSERVS           8192
 188
 189 int nfsd_nrthreads(void)
 190 {
 191         int rv = 0;
 192         mutex_lock(&nfsd_mutex);
 193         if (nfsd_serv)
 194                 rv = nfsd_serv->sv_nrthreads;
 195         mutex_unlock(&nfsd_mutex);
 196         return rv;
 197 }
 198
 199 static void nfsd_last_thread(struct svc_serv *serv)
 200 {
 201         /* When last nfsd thread exits we need to do some clean-up */
 202         struct svc_xprt *xprt;
 203         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list)
 204                 lockd_down();
 205         nfsd_serv = NULL;
 206         nfsd_racache_shutdown();
 207         nfs4_state_shutdown();
 208
 209         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
 210                             "cache\n");
 211         nfsd_export_flush();
 212 }
 213
 214 void nfsd_reset_versions(void)
 215 {
 216         int found_one = 0;
 217         int i;
 218
 219         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 220                 if (nfsd_program.pg_vers[i])
 221                         found_one = 1;
 222         }
 223
 224         if (!found_one) {
 225                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 226                         nfsd_program.pg_vers[i] = nfsd_version[i];
 227 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 228                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 229                         nfsd_acl_program.pg_vers[i] =
 230                                 nfsd_acl_version[i];
 231 #endif
 232         }
 233 }
 234
 235 /*
 236  * Each session guarantees a negotiated per slot memory cache for replies
 237  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 238  * NFSv4.1 server might want to use more memory for a DRC than a machine
 239  * with mutiple services.
 240  *
 241  * Impose a hard limit on the number of pages for the DRC which varies
 242  * according to the machines free pages. This is of course only a default.
 243  *
 244  * For now this is a #defined shift which could be under admin control
 245  * in the future.
 246  */
 247 static void set_max_drc(void)
 248 {
 249         #define NFSD_DRC_SIZE_SHIFT     10
 250         nfsd_drc_max_mem = (nr_free_buffer_pages()
 251                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
 252         nfsd_drc_mem_used = 0;
 253         spin_lock_init(&nfsd_drc_lock);
 254         dprintk("%s nfsd_drc_max_mem %u \n", __func__, nfsd_drc_max_mem);
 255 }
 256
 257 int nfsd_create_serv(void)
 258 {
 259         int err = 0;
 260
 261         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 262         if (nfsd_serv) {
 263                 svc_get(nfsd_serv);
 264                 return 0;
 265         }
 266         if (nfsd_max_blksize == 0) {
 267                 /* choose a suitable default */
 268                 struct sysinfo i;
 269                 si_meminfo(&i);
 270                 /* Aim for 1/4096 of memory per thread
 271                  * This gives 1MB on 4Gig machines
 272                  * But only uses 32K on 128M machines.
 273                  * Bottom out at 8K on 32M and smaller.
 274                  * Of course, this is only a default.
 275                  */
 276                 nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
 277                 i.totalram <<= PAGE_SHIFT - 12;
 278                 while (nfsd_max_blksize > i.totalram &&
 279                        nfsd_max_blksize >= 8*1024*2)
 280                         nfsd_max_blksize /= 2;
 281         }
 282
 283         nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
 284                                       nfsd_last_thread, nfsd, THIS_MODULE);
 285         if (nfsd_serv == NULL)
 286                 err = -ENOMEM;
 287         else
 288                 set_max_drc();
 289
 290         do_gettimeofday(&nfssvc_boot);          /* record boot time */
 291         return err;
 292 }
 293
 294 static int nfsd_init_socks(int port)
 295 {
 296         int error;
 297         if (!list_empty(&nfsd_serv->sv_permsocks))
 298                 return 0;
 299
 300         error = svc_create_xprt(nfsd_serv, "udp", PF_INET, port,
 301                                         SVC_SOCK_DEFAULTS);
 302         if (error < 0)
 303                 return error;
 304
 305         error = lockd_up();
 306         if (error < 0)
 307                 return error;
 308
 309         error = svc_create_xprt(nfsd_serv, "tcp", PF_INET, port,
 310                                         SVC_SOCK_DEFAULTS);
 311         if (error < 0)
 312                 return error;
 313
 314         error = lockd_up();
 315         if (error < 0)
 316                 return error;
 317
 318         return 0;
 319 }
 320
 321 int nfsd_nrpools(void)
 322 {
 323         if (nfsd_serv == NULL)
 324                 return 0;
 325         else
 326                 return nfsd_serv->sv_nrpools;
 327 }
 328
 329 int nfsd_get_nrthreads(int n, int *nthreads)
 330 {
 331         int i = 0;
 332
 333         if (nfsd_serv != NULL) {
 334                 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
 335                         nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
 336         }
 337
 338         return 0;
 339 }
 340
 341 int nfsd_set_nrthreads(int n, int *nthreads)
 342 {
 343         int i = 0;
 344         int tot = 0;
 345         int err = 0;
 346
 347         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 348
 349         if (nfsd_serv == NULL || n <= 0)
 350                 return 0;
 351
 352         if (n > nfsd_serv->sv_nrpools)
 353                 n = nfsd_serv->sv_nrpools;
 354
 355         /* enforce a global maximum number of threads */
 356         tot = 0;
 357         for (i = 0; i < n; i++) {
 358                 if (nthreads[i] > NFSD_MAXSERVS)
 359                         nthreads[i] = NFSD_MAXSERVS;
 360                 tot += nthreads[i];
 361         }
 362         if (tot > NFSD_MAXSERVS) {
 363                 /* total too large: scale down requested numbers */
 364                 for (i = 0; i < n && tot > 0; i++) {
 365                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 366                         tot -= (nthreads[i] - new);
 367                         nthreads[i] = new;
 368                 }
 369                 for (i = 0; i < n && tot > 0; i++) {
 370                         nthreads[i]--;
 371                         tot--;
 372                 }
 373         }
 374
 375         /*
 376          * There must always be a thread in pool 0; the admin
 377          * can't shut down NFS completely using pool_threads.
 378          */
 379         if (nthreads[0] == 0)
 380                 nthreads[0] = 1;
 381
 382         /* apply the new numbers */
 383         svc_get(nfsd_serv);
 384         for (i = 0; i < n; i++) {
 385                 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
 386                                           nthreads[i]);
 387                 if (err)
 388                         break;
 389         }
 390         svc_destroy(nfsd_serv);
 391
 392         return err;
 393 }
 394
 395 int
 396 nfsd_svc(unsigned short port, int nrservs)
 397 {
 398         int     error;
 399
 400         mutex_lock(&nfsd_mutex);
 401         dprintk("nfsd: creating service\n");
 402         if (nrservs <= 0)
 403                 nrservs = 0;
 404         if (nrservs > NFSD_MAXSERVS)
 405                 nrservs = NFSD_MAXSERVS;
 406         error = 0;
 407         if (nrservs == 0 && nfsd_serv == NULL)
 408                 goto out;
 409
 410         /* Readahead param cache - will no-op if it already exists */
 411         error = nfsd_racache_init(2*nrservs);
 412         if (error<0)
 413                 goto out;
 414         nfs4_state_start();
 415
 416         nfsd_reset_versions();
 417
 418         error = nfsd_create_serv();
 419
 420         if (error)
 421                 goto out;
 422         error = nfsd_init_socks(port);
 423         if (error)
 424                 goto failure;
 425
 426         error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
 427         if (error == 0)
 428                 /* We are holding a reference to nfsd_serv which
 429                  * we don't want to count in the return value,
 430                  * so subtract 1
 431                  */
 432                 error = nfsd_serv->sv_nrthreads - 1;
 433  failure:
 434         svc_destroy(nfsd_serv);         /* Release server */
 435  out:
 436         mutex_unlock(&nfsd_mutex);
 437         return error;
 438 }
 439
 440
 441 /*
 442  * This is the NFS server kernel thread
 443  */
 444 static int
 445 nfsd(void *vrqstp)
 446 {
 447         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 448         int err, preverr = 0;
 449
 450         /* Lock module and set up kernel thread */
 451         mutex_lock(&nfsd_mutex);
 452
 453         /* At this point, the thread shares current->fs
 454          * with the init process. We need to create files with a
 455          * umask of 0 instead of init's umask. */
 456         if (unshare_fs_struct() < 0) {
 457                 printk("Unable to start nfsd thread: out of memory\n");
 458                 goto out;
 459         }
 460
 461         current->fs->umask = 0;
 462
 463         /*
 464          * thread is spawned with all signals set to SIG_IGN, re-enable
 465          * the ones that will bring down the thread
 466          */
 467         allow_signal(SIGKILL);
 468         allow_signal(SIGHUP);
 469         allow_signal(SIGINT);
 470         allow_signal(SIGQUIT);
 471
 472         nfsdstats.th_cnt++;
 473         mutex_unlock(&nfsd_mutex);
 474
 475         /*
 476          * We want less throttling in balance_dirty_pages() so that nfs to
 477          * localhost doesn't cause nfsd to lock up due to all the client's
 478          * dirty pages.
 479          */
 480         current->flags |= PF_LESS_THROTTLE;
 481         set_freezable();
 482
 483         /*
 484          * The main request loop
 485          */
 486         for (;;) {
 487                 /*
 488                  * Find a socket with data available and call its
 489                  * recvfrom routine.
 490                  */
 491                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 492                         ;
 493                 if (err == -EINTR)
 494                         break;
 495                 else if (err < 0) {
 496                         if (err != preverr) {
 497                                 printk(KERN_WARNING "%s: unexpected error "
 498                                         "from svc_recv (%d)\n", __func__, -err);
 499                                 preverr = err;
 500                         }
 501                         schedule_timeout_uninterruptible(HZ);
 502                         continue;
 503                 }
 504
 505
 506                 /* Lock the export hash tables for reading. */
 507                 exp_readlock();
 508
 509                 svc_process(rqstp);
 510
 511                 /* Unlock export hash tables */
 512                 exp_readunlock();
 513         }
 514
 515         /* Clear signals before calling svc_exit_thread() */
 516         flush_signals(current);
 517
 518         mutex_lock(&nfsd_mutex);
 519         nfsdstats.th_cnt --;
 520
 521 out:
 522         /* Release the thread */
 523         svc_exit_thread(rqstp);
 524
 525         /* Release module */
 526         mutex_unlock(&nfsd_mutex);
 527         module_put_and_exit(0);
 528         return 0;
 529 }
 530
 531 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 532 {
 533         if (nfserr == nfserr_jukebox && vers == 2)
 534                 return nfserr_dropit;
 535         if (nfserr == nfserr_wrongsec && vers < 4)
 536                 return nfserr_acces;
 537         return nfserr;
 538 }
 539
 540 int
 541 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 542 {
 543         struct svc_procedure    *proc;
 544         kxdrproc_t              xdr;
 545         __be32                  nfserr;
 546         __be32                  *nfserrp;
 547
 548         dprintk("nfsd_dispatch: vers %d proc %d\n",
 549                                 rqstp->rq_vers, rqstp->rq_proc);
 550         proc = rqstp->rq_procinfo;
 551
 552         /* Check whether we have this call in the cache. */
 553         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
 554         case RC_INTR:
 555         case RC_DROPIT:
 556                 return 0;
 557         case RC_REPLY:
 558                 return 1;
 559         case RC_DOIT:;
 560                 /* do it */
 561         }
 562
 563         /* Decode arguments */
 564         xdr = proc->pc_decode;
 565         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 566                         rqstp->rq_argp)) {
 567                 dprintk("nfsd: failed to decode arguments!\n");
 568                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 569                 *statp = rpc_garbage_args;
 570                 return 1;
 571         }
 572
 573         /* need to grab the location to store the status, as
 574          * nfsv4 does some encoding while processing
 575          */
 576         nfserrp = rqstp->rq_res.head[0].iov_base
 577                 + rqstp->rq_res.head[0].iov_len;
 578         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 579
 580         /* Now call the procedure handler, and encode NFS status. */
 581         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 582         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 583         if (nfserr == nfserr_dropit) {
 584                 dprintk("nfsd: Dropping request; may be revisited later\n");
 585                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 586                 return 0;
 587         }
 588
 589         if (rqstp->rq_proc != 0)
 590                 *nfserrp++ = nfserr;
 591
 592         /* Encode result.
 593          * For NFSv2, additional info is never returned in case of an error.
 594          */
 595         if (!(nfserr && rqstp->rq_vers == 2)) {
 596                 xdr = proc->pc_encode;
 597                 if (xdr && !xdr(rqstp, nfserrp,
 598                                 rqstp->rq_resp)) {
 599                         /* Failed to encode result. Release cache entry */
 600                         dprintk("nfsd: failed to encode result!\n");
 601                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 602                         *statp = rpc_system_err;
 603                         return 1;
 604                 }
 605         }
 606
 607         /* Store reply in cache. */
 608         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 609         return 1;
 610 }
 611
 612 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 613 {
 614         int ret;
 615         mutex_lock(&nfsd_mutex);
 616         if (nfsd_serv == NULL) {
 617                 mutex_unlock(&nfsd_mutex);
 618                 return -ENODEV;
 619         }
 620         /* bump up the psudo refcount while traversing */
 621         svc_get(nfsd_serv);
 622         ret = svc_pool_stats_open(nfsd_serv, file);
 623         mutex_unlock(&nfsd_mutex);
 624         return ret;
 625 }
 626
 627 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 628 {
 629         int ret = seq_release(inode, file);
 630         mutex_lock(&nfsd_mutex);
 631         /* this function really, really should have been called svc_put() */
 632         svc_destroy(nfsd_serv);
 633         mutex_unlock(&nfsd_mutex);
 634         return ret;
 635 }