fs/nfsd/nfssvc.c

   1 /*
   2  * Central processing for nfsd.
   3  *
   4  * Authors:     Olaf Kirch (okir@monad.swb.de)
   5  *
   6  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/sched.h>
  10 #include <linux/freezer.h>
  11 #include <linux/module.h>
  12 #include <linux/fs_struct.h>
  13 #include <linux/swap.h>
  14
  15 #include <linux/sunrpc/stats.h>
  16 #include <linux/sunrpc/svcsock.h>
  17 #include <linux/lockd/bind.h>
  18 #include <linux/nfsacl.h>
  19 #include <linux/seq_file.h>
  20 #include <net/net_namespace.h>
  21 #include "nfsd.h"
  22 #include "cache.h"
  23 #include "vfs.h"
  24
  25 #define NFSDDBG_FACILITY        NFSDDBG_SVC
  26
  27 extern struct svc_program       nfsd_program;
  28 static int                      nfsd(void *vrqstp);
  29 struct timeval                  nfssvc_boot;
  30
  31 /*
  32  * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members
  33  * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
  34  * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
  35  *
  36  * If (out side the lock) nfsd_serv is non-NULL, then it must point to a
  37  * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
  38  * of nfsd threads must exist and each must listed in ->sp_all_threads in each
  39  * entry of ->sv_pools[].
  40  *
  41  * Transitions of the thread count between zero and non-zero are of particular
  42  * interest since the svc_serv needs to be created and initialized at that
  43  * point, or freed.
  44  *
  45  * Finally, the nfsd_mutex also protects some of the global variables that are
  46  * accessed when nfsd starts and that are settable via the write_* routines in
  47  * nfsctl.c. In particular:
  48  *
  49  *      user_recovery_dirname
  50  *      user_lease_time
  51  *      nfsd_versions
  52  */
  53 DEFINE_MUTEX(nfsd_mutex);
  54 struct svc_serv                 *nfsd_serv;
  55
  56 /*
  57  * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
  58  * nfsd_drc_max_pages limits the total amount of memory available for
  59  * version 4.1 DRC caches.
  60  * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
  61  */
  62 spinlock_t      nfsd_drc_lock;
  63 unsigned int    nfsd_drc_max_mem;
  64 unsigned int    nfsd_drc_mem_used;
  65
  66 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  67 static struct svc_stat  nfsd_acl_svcstats;
  68 static struct svc_version *     nfsd_acl_version[] = {
  69         [2] = &nfsd_acl_version2,
  70         [3] = &nfsd_acl_version3,
  71 };
  72
  73 #define NFSD_ACL_MINVERS            2
  74 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  75 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  76
  77 static struct svc_program       nfsd_acl_program = {
  78         .pg_prog                = NFS_ACL_PROGRAM,
  79         .pg_nvers               = NFSD_ACL_NRVERS,
  80         .pg_vers                = nfsd_acl_versions,
  81         .pg_name                = "nfsacl",
  82         .pg_class               = "nfsd",
  83         .pg_stats               = &nfsd_acl_svcstats,
  84         .pg_authenticate        = &svc_set_client,
  85 };
  86
  87 static struct svc_stat  nfsd_acl_svcstats = {
  88         .program        = &nfsd_acl_program,
  89 };
  90 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  91
  92 static struct svc_version *     nfsd_version[] = {
  93         [2] = &nfsd_version2,
  94 #if defined(CONFIG_NFSD_V3)
  95         [3] = &nfsd_version3,
  96 #endif
  97 #if defined(CONFIG_NFSD_V4)
  98         [4] = &nfsd_version4,
  99 #endif
 100 };
 101
 102 #define NFSD_MINVERS            2
 103 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
 104 static struct svc_version *nfsd_versions[NFSD_NRVERS];
 105
 106 struct svc_program              nfsd_program = {
 107 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 108         .pg_next                = &nfsd_acl_program,
 109 #endif
 110         .pg_prog                = NFS_PROGRAM,          /* program number */
 111         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 112         .pg_vers                = nfsd_versions,        /* version table */
 113         .pg_name                = "nfsd",               /* program name */
 114         .pg_class               = "nfsd",               /* authentication class */
 115         .pg_stats               = &nfsd_svcstats,       /* version table */
 116         .pg_authenticate        = &svc_set_client,      /* export authentication */
 117
 118 };
 119
 120 u32 nfsd_supported_minorversion;
 121
 122 int nfsd_vers(int vers, enum vers_op change)
 123 {
 124         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
 125                 return 0;
 126         switch(change) {
 127         case NFSD_SET:
 128                 nfsd_versions[vers] = nfsd_version[vers];
 129 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 130                 if (vers < NFSD_ACL_NRVERS)
 131                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
 132 #endif
 133                 break;
 134         case NFSD_CLEAR:
 135                 nfsd_versions[vers] = NULL;
 136 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 137                 if (vers < NFSD_ACL_NRVERS)
 138                         nfsd_acl_versions[vers] = NULL;
 139 #endif
 140                 break;
 141         case NFSD_TEST:
 142                 return nfsd_versions[vers] != NULL;
 143         case NFSD_AVAIL:
 144                 return nfsd_version[vers] != NULL;
 145         }
 146         return 0;
 147 }
 148
 149 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 150 {
 151         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
 152                 return -1;
 153         switch(change) {
 154         case NFSD_SET:
 155                 nfsd_supported_minorversion = minorversion;
 156                 break;
 157         case NFSD_CLEAR:
 158                 if (minorversion == 0)
 159                         return -1;
 160                 nfsd_supported_minorversion = minorversion - 1;
 161                 break;
 162         case NFSD_TEST:
 163                 return minorversion <= nfsd_supported_minorversion;
 164         case NFSD_AVAIL:
 165                 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
 166         }
 167         return 0;
 168 }
 169
 170 /*
 171  * Maximum number of nfsd processes
 172  */
 173 #define NFSD_MAXSERVS           8192
 174
 175 int nfsd_nrthreads(void)
 176 {
 177         int rv = 0;
 178         mutex_lock(&nfsd_mutex);
 179         if (nfsd_serv)
 180                 rv = nfsd_serv->sv_nrthreads;
 181         mutex_unlock(&nfsd_mutex);
 182         return rv;
 183 }
 184
 185 static int nfsd_init_socks(int port)
 186 {
 187         int error;
 188         if (!list_empty(&nfsd_serv->sv_permsocks))
 189                 return 0;
 190
 191         error = svc_create_xprt(nfsd_serv, "udp", &init_net, PF_INET, port,
 192                                         SVC_SOCK_DEFAULTS);
 193         if (error < 0)
 194                 return error;
 195
 196         error = svc_create_xprt(nfsd_serv, "tcp", &init_net, PF_INET, port,
 197                                         SVC_SOCK_DEFAULTS);
 198         if (error < 0)
 199                 return error;
 200
 201         return 0;
 202 }
 203
 204 static bool nfsd_up = false;
 205
 206 static int nfsd_startup(unsigned short port, int nrservs)
 207 {
 208         int ret;
 209
 210         if (nfsd_up)
 211                 return 0;
 212         /*
 213          * Readahead param cache - will no-op if it already exists.
 214          * (Note therefore results will be suboptimal if number of
 215          * threads is modified after nfsd start.)
 216          */
 217         ret = nfsd_racache_init(2*nrservs);
 218         if (ret)
 219                 return ret;
 220         ret = nfsd_init_socks(port);
 221         if (ret)
 222                 goto out_racache;
 223         ret = lockd_up();
 224         if (ret)
 225                 goto out_racache;
 226         ret = nfs4_state_start();
 227         if (ret)
 228                 goto out_lockd;
 229         nfsd_up = true;
 230         return 0;
 231 out_lockd:
 232         lockd_down();
 233 out_racache:
 234         nfsd_racache_shutdown();
 235         return ret;
 236 }
 237
 238 static void nfsd_shutdown(void)
 239 {
 240         /*
 241          * write_ports can create the server without actually starting
 242          * any threads--if we get shut down before any threads are
 243          * started, then nfsd_last_thread will be run before any of this
 244          * other initialization has been done.
 245          */
 246         if (!nfsd_up)
 247                 return;
 248         nfs4_state_shutdown();
 249         lockd_down();
 250         nfsd_racache_shutdown();
 251         nfsd_up = false;
 252 }
 253
 254 static void nfsd_last_thread(struct svc_serv *serv)
 255 {
 256         /* When last nfsd thread exits we need to do some clean-up */
 257         nfsd_serv = NULL;
 258         nfsd_shutdown();
 259
 260         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
 261                             "cache\n");
 262         nfsd_export_flush();
 263 }
 264
 265 void nfsd_reset_versions(void)
 266 {
 267         int found_one = 0;
 268         int i;
 269
 270         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 271                 if (nfsd_program.pg_vers[i])
 272                         found_one = 1;
 273         }
 274
 275         if (!found_one) {
 276                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 277                         nfsd_program.pg_vers[i] = nfsd_version[i];
 278 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 279                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 280                         nfsd_acl_program.pg_vers[i] =
 281                                 nfsd_acl_version[i];
 282 #endif
 283         }
 284 }
 285
 286 /*
 287  * Each session guarantees a negotiated per slot memory cache for replies
 288  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 289  * NFSv4.1 server might want to use more memory for a DRC than a machine
 290  * with mutiple services.
 291  *
 292  * Impose a hard limit on the number of pages for the DRC which varies
 293  * according to the machines free pages. This is of course only a default.
 294  *
 295  * For now this is a #defined shift which could be under admin control
 296  * in the future.
 297  */
 298 static void set_max_drc(void)
 299 {
 300         #define NFSD_DRC_SIZE_SHIFT     10
 301         nfsd_drc_max_mem = (nr_free_buffer_pages()
 302                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
 303         nfsd_drc_mem_used = 0;
 304         spin_lock_init(&nfsd_drc_lock);
 305         dprintk("%s nfsd_drc_max_mem %u \n", __func__, nfsd_drc_max_mem);
 306 }
 307
 308 int nfsd_create_serv(void)
 309 {
 310         int err = 0;
 311
 312         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 313         if (nfsd_serv) {
 314                 svc_get(nfsd_serv);
 315                 return 0;
 316         }
 317         if (nfsd_max_blksize == 0) {
 318                 /* choose a suitable default */
 319                 struct sysinfo i;
 320                 si_meminfo(&i);
 321                 /* Aim for 1/4096 of memory per thread
 322                  * This gives 1MB on 4Gig machines
 323                  * But only uses 32K on 128M machines.
 324                  * Bottom out at 8K on 32M and smaller.
 325                  * Of course, this is only a default.
 326                  */
 327                 nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
 328                 i.totalram <<= PAGE_SHIFT - 12;
 329                 while (nfsd_max_blksize > i.totalram &&
 330                        nfsd_max_blksize >= 8*1024*2)
 331                         nfsd_max_blksize /= 2;
 332         }
 333         nfsd_reset_versions();
 334
 335         nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
 336                                       nfsd_last_thread, nfsd, THIS_MODULE);
 337         if (nfsd_serv == NULL)
 338                 return -ENOMEM;
 339
 340         set_max_drc();
 341         do_gettimeofday(&nfssvc_boot);          /* record boot time */
 342         return err;
 343 }
 344
 345 int nfsd_nrpools(void)
 346 {
 347         if (nfsd_serv == NULL)
 348                 return 0;
 349         else
 350                 return nfsd_serv->sv_nrpools;
 351 }
 352
 353 int nfsd_get_nrthreads(int n, int *nthreads)
 354 {
 355         int i = 0;
 356
 357         if (nfsd_serv != NULL) {
 358                 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
 359                         nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
 360         }
 361
 362         return 0;
 363 }
 364
 365 int nfsd_set_nrthreads(int n, int *nthreads)
 366 {
 367         int i = 0;
 368         int tot = 0;
 369         int err = 0;
 370
 371         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 372
 373         if (nfsd_serv == NULL || n <= 0)
 374                 return 0;
 375
 376         if (n > nfsd_serv->sv_nrpools)
 377                 n = nfsd_serv->sv_nrpools;
 378
 379         /* enforce a global maximum number of threads */
 380         tot = 0;
 381         for (i = 0; i < n; i++) {
 382                 if (nthreads[i] > NFSD_MAXSERVS)
 383                         nthreads[i] = NFSD_MAXSERVS;
 384                 tot += nthreads[i];
 385         }
 386         if (tot > NFSD_MAXSERVS) {
 387                 /* total too large: scale down requested numbers */
 388                 for (i = 0; i < n && tot > 0; i++) {
 389                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 390                         tot -= (nthreads[i] - new);
 391                         nthreads[i] = new;
 392                 }
 393                 for (i = 0; i < n && tot > 0; i++) {
 394                         nthreads[i]--;
 395                         tot--;
 396                 }
 397         }
 398
 399         /*
 400          * There must always be a thread in pool 0; the admin
 401          * can't shut down NFS completely using pool_threads.
 402          */
 403         if (nthreads[0] == 0)
 404                 nthreads[0] = 1;
 405
 406         /* apply the new numbers */
 407         svc_get(nfsd_serv);
 408         for (i = 0; i < n; i++) {
 409                 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
 410                                           nthreads[i]);
 411                 if (err)
 412                         break;
 413         }
 414         svc_destroy(nfsd_serv);
 415
 416         return err;
 417 }
 418
 419 /*
 420  * Adjust the number of threads and return the new number of threads.
 421  * This is also the function that starts the server if necessary, if
 422  * this is the first time nrservs is nonzero.
 423  */
 424 int
 425 nfsd_svc(unsigned short port, int nrservs)
 426 {
 427         int     error;
 428         bool    nfsd_up_before;
 429
 430         mutex_lock(&nfsd_mutex);
 431         dprintk("nfsd: creating service\n");
 432         if (nrservs <= 0)
 433                 nrservs = 0;
 434         if (nrservs > NFSD_MAXSERVS)
 435                 nrservs = NFSD_MAXSERVS;
 436         error = 0;
 437         if (nrservs == 0 && nfsd_serv == NULL)
 438                 goto out;
 439
 440         error = nfsd_create_serv();
 441         if (error)
 442                 goto out;
 443
 444         nfsd_up_before = nfsd_up;
 445
 446         error = nfsd_startup(port, nrservs);
 447         if (error)
 448                 goto out_destroy;
 449         error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
 450         if (error)
 451                 goto out_shutdown;
 452         /* We are holding a reference to nfsd_serv which
 453          * we don't want to count in the return value,
 454          * so subtract 1
 455          */
 456         error = nfsd_serv->sv_nrthreads - 1;
 457 out_shutdown:
 458         if (error < 0 && !nfsd_up_before)
 459                 nfsd_shutdown();
 460 out_destroy:
 461         svc_destroy(nfsd_serv);         /* Release server */
 462 out:
 463         mutex_unlock(&nfsd_mutex);
 464         return error;
 465 }
 466
 467
 468 /*
 469  * This is the NFS server kernel thread
 470  */
 471 static int
 472 nfsd(void *vrqstp)
 473 {
 474         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 475         int err, preverr = 0;
 476
 477         /* Lock module and set up kernel thread */
 478         mutex_lock(&nfsd_mutex);
 479
 480         /* At this point, the thread shares current->fs
 481          * with the init process. We need to create files with a
 482          * umask of 0 instead of init's umask. */
 483         if (unshare_fs_struct() < 0) {
 484                 printk("Unable to start nfsd thread: out of memory\n");
 485                 goto out;
 486         }
 487
 488         current->fs->umask = 0;
 489
 490         /*
 491          * thread is spawned with all signals set to SIG_IGN, re-enable
 492          * the ones that will bring down the thread
 493          */
 494         allow_signal(SIGKILL);
 495         allow_signal(SIGHUP);
 496         allow_signal(SIGINT);
 497         allow_signal(SIGQUIT);
 498
 499         nfsdstats.th_cnt++;
 500         mutex_unlock(&nfsd_mutex);
 501
 502         /*
 503          * We want less throttling in balance_dirty_pages() so that nfs to
 504          * localhost doesn't cause nfsd to lock up due to all the client's
 505          * dirty pages.
 506          */
 507         current->flags |= PF_LESS_THROTTLE;
 508         set_freezable();
 509
 510         /*
 511          * The main request loop
 512          */
 513         for (;;) {
 514                 /*
 515                  * Find a socket with data available and call its
 516                  * recvfrom routine.
 517                  */
 518                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 519                         ;
 520                 if (err == -EINTR)
 521                         break;
 522                 else if (err < 0) {
 523                         if (err != preverr) {
 524                                 printk(KERN_WARNING "%s: unexpected error "
 525                                         "from svc_recv (%d)\n", __func__, -err);
 526                                 preverr = err;
 527                         }
 528                         schedule_timeout_uninterruptible(HZ);
 529                         continue;
 530                 }
 531
 532                 validate_process_creds();
 533                 svc_process(rqstp);
 534                 validate_process_creds();
 535         }
 536
 537         /* Clear signals before calling svc_exit_thread() */
 538         flush_signals(current);
 539
 540         mutex_lock(&nfsd_mutex);
 541         nfsdstats.th_cnt --;
 542
 543 out:
 544         /* Release the thread */
 545         svc_exit_thread(rqstp);
 546
 547         /* Release module */
 548         mutex_unlock(&nfsd_mutex);
 549         module_put_and_exit(0);
 550         return 0;
 551 }
 552
 553 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 554 {
 555         if (nfserr == nfserr_jukebox && vers == 2)
 556                 return nfserr_dropit;
 557         if (nfserr == nfserr_wrongsec && vers < 4)
 558                 return nfserr_acces;
 559         return nfserr;
 560 }
 561
 562 int
 563 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 564 {
 565         struct svc_procedure    *proc;
 566         kxdrproc_t              xdr;
 567         __be32                  nfserr;
 568         __be32                  *nfserrp;
 569
 570         dprintk("nfsd_dispatch: vers %d proc %d\n",
 571                                 rqstp->rq_vers, rqstp->rq_proc);
 572         proc = rqstp->rq_procinfo;
 573
 574         /*
 575          * Give the xdr decoder a chance to change this if it wants
 576          * (necessary in the NFSv4.0 compound case)
 577          */
 578         rqstp->rq_cachetype = proc->pc_cachetype;
 579         /* Decode arguments */
 580         xdr = proc->pc_decode;
 581         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 582                         rqstp->rq_argp)) {
 583                 dprintk("nfsd: failed to decode arguments!\n");
 584                 *statp = rpc_garbage_args;
 585                 return 1;
 586         }
 587
 588         /* Check whether we have this call in the cache. */
 589         switch (nfsd_cache_lookup(rqstp)) {
 590         case RC_INTR:
 591         case RC_DROPIT:
 592                 return 0;
 593         case RC_REPLY:
 594                 return 1;
 595         case RC_DOIT:;
 596                 /* do it */
 597         }
 598
 599         /* need to grab the location to store the status, as
 600          * nfsv4 does some encoding while processing
 601          */
 602         nfserrp = rqstp->rq_res.head[0].iov_base
 603                 + rqstp->rq_res.head[0].iov_len;
 604         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 605
 606         /* Now call the procedure handler, and encode NFS status. */
 607         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 608         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 609         if (nfserr == nfserr_dropit || rqstp->rq_dropme) {
 610                 dprintk("nfsd: Dropping request; may be revisited later\n");
 611                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 612                 return 0;
 613         }
 614
 615         if (rqstp->rq_proc != 0)
 616                 *nfserrp++ = nfserr;
 617
 618         /* Encode result.
 619          * For NFSv2, additional info is never returned in case of an error.
 620          */
 621         if (!(nfserr && rqstp->rq_vers == 2)) {
 622                 xdr = proc->pc_encode;
 623                 if (xdr && !xdr(rqstp, nfserrp,
 624                                 rqstp->rq_resp)) {
 625                         /* Failed to encode result. Release cache entry */
 626                         dprintk("nfsd: failed to encode result!\n");
 627                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 628                         *statp = rpc_system_err;
 629                         return 1;
 630                 }
 631         }
 632
 633         /* Store reply in cache. */
 634         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 635         return 1;
 636 }
 637
 638 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 639 {
 640         int ret;
 641         mutex_lock(&nfsd_mutex);
 642         if (nfsd_serv == NULL) {
 643                 mutex_unlock(&nfsd_mutex);
 644                 return -ENODEV;
 645         }
 646         /* bump up the psudo refcount while traversing */
 647         svc_get(nfsd_serv);
 648         ret = svc_pool_stats_open(nfsd_serv, file);
 649         mutex_unlock(&nfsd_mutex);
 650         return ret;
 651 }
 652
 653 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 654 {
 655         int ret = seq_release(inode, file);
 656         mutex_lock(&nfsd_mutex);
 657         /* this function really, really should have been called svc_put() */
 658         svc_destroy(nfsd_serv);
 659         mutex_unlock(&nfsd_mutex);
 660         return ret;
 661 }