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 #include "netns.h"
  25
  26 #define NFSDDBG_FACILITY        NFSDDBG_SVC
  27
  28 extern struct svc_program       nfsd_program;
  29 static int                      nfsd(void *vrqstp);
  30
  31 /*
  32  * nfsd_mutex protects nn->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) nn->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
  55 /*
  56  * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
  57  * nfsd_drc_max_pages limits the total amount of memory available for
  58  * version 4.1 DRC caches.
  59  * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
  60  */
  61 spinlock_t      nfsd_drc_lock;
  62 unsigned long   nfsd_drc_max_mem;
  63 unsigned long   nfsd_drc_mem_used;
  64
  65 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  66 static struct svc_stat  nfsd_acl_svcstats;
  67 static struct svc_version *     nfsd_acl_version[] = {
  68         [2] = &nfsd_acl_version2,
  69         [3] = &nfsd_acl_version3,
  70 };
  71
  72 #define NFSD_ACL_MINVERS            2
  73 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  74 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  75
  76 static struct svc_program       nfsd_acl_program = {
  77         .pg_prog                = NFS_ACL_PROGRAM,
  78         .pg_nvers               = NFSD_ACL_NRVERS,
  79         .pg_vers                = nfsd_acl_versions,
  80         .pg_name                = "nfsacl",
  81         .pg_class               = "nfsd",
  82         .pg_stats               = &nfsd_acl_svcstats,
  83         .pg_authenticate        = &svc_set_client,
  84 };
  85
  86 static struct svc_stat  nfsd_acl_svcstats = {
  87         .program        = &nfsd_acl_program,
  88 };
  89 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  90
  91 static struct svc_version *     nfsd_version[] = {
  92         [2] = &nfsd_version2,
  93 #if defined(CONFIG_NFSD_V3)
  94         [3] = &nfsd_version3,
  95 #endif
  96 #if defined(CONFIG_NFSD_V4)
  97         [4] = &nfsd_version4,
  98 #endif
  99 };
 100
 101 #define NFSD_MINVERS            2
 102 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
 103 static struct svc_version *nfsd_versions[NFSD_NRVERS];
 104
 105 struct svc_program              nfsd_program = {
 106 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 107         .pg_next                = &nfsd_acl_program,
 108 #endif
 109         .pg_prog                = NFS_PROGRAM,          /* program number */
 110         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 111         .pg_vers                = nfsd_versions,        /* version table */
 112         .pg_name                = "nfsd",               /* program name */
 113         .pg_class               = "nfsd",               /* authentication class */
 114         .pg_stats               = &nfsd_svcstats,       /* version table */
 115         .pg_authenticate        = &svc_set_client,      /* export authentication */
 116
 117 };
 118
 119 static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = {
 120         [0] = 1,
 121         [1] = 1,
 122         [2] = 1,
 123 };
 124
 125 int nfsd_vers(int vers, enum vers_op change)
 126 {
 127         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
 128                 return 0;
 129         switch(change) {
 130         case NFSD_SET:
 131                 nfsd_versions[vers] = nfsd_version[vers];
 132 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 133                 if (vers < NFSD_ACL_NRVERS)
 134                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
 135 #endif
 136                 break;
 137         case NFSD_CLEAR:
 138                 nfsd_versions[vers] = NULL;
 139 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 140                 if (vers < NFSD_ACL_NRVERS)
 141                         nfsd_acl_versions[vers] = NULL;
 142 #endif
 143                 break;
 144         case NFSD_TEST:
 145                 return nfsd_versions[vers] != NULL;
 146         case NFSD_AVAIL:
 147                 return nfsd_version[vers] != NULL;
 148         }
 149         return 0;
 150 }
 151
 152 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 153 {
 154         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
 155                 return -1;
 156         switch(change) {
 157         case NFSD_SET:
 158                 nfsd_supported_minorversions[minorversion] = true;
 159                 break;
 160         case NFSD_CLEAR:
 161                 nfsd_supported_minorversions[minorversion] = false;
 162                 break;
 163         case NFSD_TEST:
 164                 return nfsd_supported_minorversions[minorversion];
 165         case NFSD_AVAIL:
 166                 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
 167         }
 168         return 0;
 169 }
 170
 171 /*
 172  * Maximum number of nfsd processes
 173  */
 174 #define NFSD_MAXSERVS           8192
 175
 176 int nfsd_nrthreads(struct net *net)
 177 {
 178         int rv = 0;
 179         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 180
 181         mutex_lock(&nfsd_mutex);
 182         if (nn->nfsd_serv)
 183                 rv = nn->nfsd_serv->sv_nrthreads;
 184         mutex_unlock(&nfsd_mutex);
 185         return rv;
 186 }
 187
 188 static int nfsd_init_socks(struct net *net)
 189 {
 190         int error;
 191         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 192
 193         if (!list_empty(&nn->nfsd_serv->sv_permsocks))
 194                 return 0;
 195
 196         error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
 197                                         SVC_SOCK_DEFAULTS);
 198         if (error < 0)
 199                 return error;
 200
 201         error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
 202                                         SVC_SOCK_DEFAULTS);
 203         if (error < 0)
 204                 return error;
 205
 206         return 0;
 207 }
 208
 209 static int nfsd_users = 0;
 210
 211 static int nfsd_startup_generic(int nrservs)
 212 {
 213         int ret;
 214
 215         if (nfsd_users++)
 216                 return 0;
 217
 218         /*
 219          * Readahead param cache - will no-op if it already exists.
 220          * (Note therefore results will be suboptimal if number of
 221          * threads is modified after nfsd start.)
 222          */
 223         ret = nfsd_racache_init(2*nrservs);
 224         if (ret)
 225                 goto dec_users;
 226
 227         ret = nfs4_state_start();
 228         if (ret)
 229                 goto out_racache;
 230         return 0;
 231
 232 out_racache:
 233         nfsd_racache_shutdown();
 234 dec_users:
 235         nfsd_users--;
 236         return ret;
 237 }
 238
 239 static void nfsd_shutdown_generic(void)
 240 {
 241         if (--nfsd_users)
 242                 return;
 243
 244         nfs4_state_shutdown();
 245         nfsd_racache_shutdown();
 246 }
 247
 248 static bool nfsd_needs_lockd(void)
 249 {
 250 #if defined(CONFIG_NFSD_V3)
 251         return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
 252 #else
 253         return (nfsd_versions[2] != NULL);
 254 #endif
 255 }
 256
 257 static int nfsd_startup_net(int nrservs, struct net *net)
 258 {
 259         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 260         int ret;
 261
 262         if (nn->nfsd_net_up)
 263                 return 0;
 264
 265         ret = nfsd_startup_generic(nrservs);
 266         if (ret)
 267                 return ret;
 268         ret = nfsd_init_socks(net);
 269         if (ret)
 270                 goto out_socks;
 271
 272         if (nfsd_needs_lockd() && !nn->lockd_up) {
 273                 ret = lockd_up(net);
 274                 if (ret)
 275                         goto out_socks;
 276                 nn->lockd_up = 1;
 277         }
 278
 279         ret = nfs4_state_start_net(net);
 280         if (ret)
 281                 goto out_lockd;
 282
 283         nn->nfsd_net_up = true;
 284         return 0;
 285
 286 out_lockd:
 287         if (nn->lockd_up) {
 288                 lockd_down(net);
 289                 nn->lockd_up = 0;
 290         }
 291 out_socks:
 292         nfsd_shutdown_generic();
 293         return ret;
 294 }
 295
 296 static void nfsd_shutdown_net(struct net *net)
 297 {
 298         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 299
 300         nfs4_state_shutdown_net(net);
 301         if (nn->lockd_up) {
 302                 lockd_down(net);
 303                 nn->lockd_up = 0;
 304         }
 305         nn->nfsd_net_up = false;
 306         nfsd_shutdown_generic();
 307 }
 308
 309 static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
 310 {
 311         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 312
 313         /*
 314          * write_ports can create the server without actually starting
 315          * any threads--if we get shut down before any threads are
 316          * started, then nfsd_last_thread will be run before any of this
 317          * other initialization has been done.
 318          */
 319         if (!nn->nfsd_net_up)
 320                 return;
 321         nfsd_shutdown_net(net);
 322
 323         svc_rpcb_cleanup(serv, net);
 324
 325         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
 326                             "cache\n");
 327         nfsd_export_flush(net);
 328 }
 329
 330 void nfsd_reset_versions(void)
 331 {
 332         int found_one = 0;
 333         int i;
 334
 335         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 336                 if (nfsd_program.pg_vers[i])
 337                         found_one = 1;
 338         }
 339
 340         if (!found_one) {
 341                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 342                         nfsd_program.pg_vers[i] = nfsd_version[i];
 343 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 344                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 345                         nfsd_acl_program.pg_vers[i] =
 346                                 nfsd_acl_version[i];
 347 #endif
 348         }
 349 }
 350
 351 /*
 352  * Each session guarantees a negotiated per slot memory cache for replies
 353  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 354  * NFSv4.1 server might want to use more memory for a DRC than a machine
 355  * with mutiple services.
 356  *
 357  * Impose a hard limit on the number of pages for the DRC which varies
 358  * according to the machines free pages. This is of course only a default.
 359  *
 360  * For now this is a #defined shift which could be under admin control
 361  * in the future.
 362  */
 363 static void set_max_drc(void)
 364 {
 365         #define NFSD_DRC_SIZE_SHIFT     10
 366         nfsd_drc_max_mem = (nr_free_buffer_pages()
 367                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
 368         nfsd_drc_mem_used = 0;
 369         spin_lock_init(&nfsd_drc_lock);
 370         dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
 371 }
 372
 373 static int nfsd_get_default_max_blksize(void)
 374 {
 375         struct sysinfo i;
 376         unsigned long long target;
 377         unsigned long ret;
 378
 379         si_meminfo(&i);
 380         target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
 381         /*
 382          * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
 383          * machines, but only uses 32K on 128M machines.  Bottom out at
 384          * 8K on 32M and smaller.  Of course, this is only a default.
 385          */
 386         target >>= 12;
 387
 388         ret = NFSSVC_MAXBLKSIZE;
 389         while (ret > target && ret >= 8*1024*2)
 390                 ret /= 2;
 391         return ret;
 392 }
 393
 394 int nfsd_create_serv(struct net *net)
 395 {
 396         int error;
 397         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 398
 399         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 400         if (nn->nfsd_serv) {
 401                 svc_get(nn->nfsd_serv);
 402                 return 0;
 403         }
 404         if (nfsd_max_blksize == 0)
 405                 nfsd_max_blksize = nfsd_get_default_max_blksize();
 406         nfsd_reset_versions();
 407         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
 408                                       nfsd_last_thread, nfsd, THIS_MODULE);
 409         if (nn->nfsd_serv == NULL)
 410                 return -ENOMEM;
 411
 412         nn->nfsd_serv->sv_maxconn = nn->max_connections;
 413         error = svc_bind(nn->nfsd_serv, net);
 414         if (error < 0) {
 415                 svc_destroy(nn->nfsd_serv);
 416                 return error;
 417         }
 418
 419         set_max_drc();
 420         do_gettimeofday(&nn->nfssvc_boot);              /* record boot time */
 421         return 0;
 422 }
 423
 424 int nfsd_nrpools(struct net *net)
 425 {
 426         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 427
 428         if (nn->nfsd_serv == NULL)
 429                 return 0;
 430         else
 431                 return nn->nfsd_serv->sv_nrpools;
 432 }
 433
 434 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
 435 {
 436         int i = 0;
 437         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 438
 439         if (nn->nfsd_serv != NULL) {
 440                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
 441                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
 442         }
 443
 444         return 0;
 445 }
 446
 447 void nfsd_destroy(struct net *net)
 448 {
 449         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 450         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
 451
 452         if (destroy)
 453                 svc_shutdown_net(nn->nfsd_serv, net);
 454         svc_destroy(nn->nfsd_serv);
 455         if (destroy)
 456                 nn->nfsd_serv = NULL;
 457 }
 458
 459 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 460 {
 461         int i = 0;
 462         int tot = 0;
 463         int err = 0;
 464         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 465
 466         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 467
 468         if (nn->nfsd_serv == NULL || n <= 0)
 469                 return 0;
 470
 471         if (n > nn->nfsd_serv->sv_nrpools)
 472                 n = nn->nfsd_serv->sv_nrpools;
 473
 474         /* enforce a global maximum number of threads */
 475         tot = 0;
 476         for (i = 0; i < n; i++) {
 477                 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
 478                 tot += nthreads[i];
 479         }
 480         if (tot > NFSD_MAXSERVS) {
 481                 /* total too large: scale down requested numbers */
 482                 for (i = 0; i < n && tot > 0; i++) {
 483                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 484                         tot -= (nthreads[i] - new);
 485                         nthreads[i] = new;
 486                 }
 487                 for (i = 0; i < n && tot > 0; i++) {
 488                         nthreads[i]--;
 489                         tot--;
 490                 }
 491         }
 492
 493         /*
 494          * There must always be a thread in pool 0; the admin
 495          * can't shut down NFS completely using pool_threads.
 496          */
 497         if (nthreads[0] == 0)
 498                 nthreads[0] = 1;
 499
 500         /* apply the new numbers */
 501         svc_get(nn->nfsd_serv);
 502         for (i = 0; i < n; i++) {
 503                 err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
 504                                           nthreads[i]);
 505                 if (err)
 506                         break;
 507         }
 508         nfsd_destroy(net);
 509         return err;
 510 }
 511
 512 /*
 513  * Adjust the number of threads and return the new number of threads.
 514  * This is also the function that starts the server if necessary, if
 515  * this is the first time nrservs is nonzero.
 516  */
 517 int
 518 nfsd_svc(int nrservs, struct net *net)
 519 {
 520         int     error;
 521         bool    nfsd_up_before;
 522         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 523
 524         mutex_lock(&nfsd_mutex);
 525         dprintk("nfsd: creating service\n");
 526
 527         nrservs = max(nrservs, 0);
 528         nrservs = min(nrservs, NFSD_MAXSERVS);
 529         error = 0;
 530
 531         if (nrservs == 0 && nn->nfsd_serv == NULL)
 532                 goto out;
 533
 534         error = nfsd_create_serv(net);
 535         if (error)
 536                 goto out;
 537
 538         nfsd_up_before = nn->nfsd_net_up;
 539
 540         error = nfsd_startup_net(nrservs, net);
 541         if (error)
 542                 goto out_destroy;
 543         error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
 544         if (error)
 545                 goto out_shutdown;
 546         /* We are holding a reference to nn->nfsd_serv which
 547          * we don't want to count in the return value,
 548          * so subtract 1
 549          */
 550         error = nn->nfsd_serv->sv_nrthreads - 1;
 551 out_shutdown:
 552         if (error < 0 && !nfsd_up_before)
 553                 nfsd_shutdown_net(net);
 554 out_destroy:
 555         nfsd_destroy(net);              /* Release server */
 556 out:
 557         mutex_unlock(&nfsd_mutex);
 558         return error;
 559 }
 560
 561
 562 /*
 563  * This is the NFS server kernel thread
 564  */
 565 static int
 566 nfsd(void *vrqstp)
 567 {
 568         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 569         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
 570         struct net *net = perm_sock->xpt_net;
 571         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 572         int err;
 573
 574         /* Lock module and set up kernel thread */
 575         mutex_lock(&nfsd_mutex);
 576
 577         /* At this point, the thread shares current->fs
 578          * with the init process. We need to create files with a
 579          * umask of 0 instead of init's umask. */
 580         if (unshare_fs_struct() < 0) {
 581                 printk("Unable to start nfsd thread: out of memory\n");
 582                 goto out;
 583         }
 584
 585         current->fs->umask = 0;
 586
 587         /*
 588          * thread is spawned with all signals set to SIG_IGN, re-enable
 589          * the ones that will bring down the thread
 590          */
 591         allow_signal(SIGKILL);
 592         allow_signal(SIGHUP);
 593         allow_signal(SIGINT);
 594         allow_signal(SIGQUIT);
 595
 596         nfsdstats.th_cnt++;
 597         mutex_unlock(&nfsd_mutex);
 598
 599         set_freezable();
 600
 601         /*
 602          * The main request loop
 603          */
 604         for (;;) {
 605                 /* Update sv_maxconn if it has changed */
 606                 rqstp->rq_server->sv_maxconn = nn->max_connections;
 607
 608                 /*
 609                  * Find a socket with data available and call its
 610                  * recvfrom routine.
 611                  */
 612                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 613                         ;
 614                 if (err == -EINTR)
 615                         break;
 616                 validate_process_creds();
 617                 svc_process(rqstp);
 618                 validate_process_creds();
 619         }
 620
 621         /* Clear signals before calling svc_exit_thread() */
 622         flush_signals(current);
 623
 624         mutex_lock(&nfsd_mutex);
 625         nfsdstats.th_cnt --;
 626
 627 out:
 628         rqstp->rq_server = NULL;
 629
 630         /* Release the thread */
 631         svc_exit_thread(rqstp);
 632
 633         nfsd_destroy(net);
 634
 635         /* Release module */
 636         mutex_unlock(&nfsd_mutex);
 637         module_put_and_exit(0);
 638         return 0;
 639 }
 640
 641 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 642 {
 643         if (nfserr == nfserr_jukebox && vers == 2)
 644                 return nfserr_dropit;
 645         if (nfserr == nfserr_wrongsec && vers < 4)
 646                 return nfserr_acces;
 647         return nfserr;
 648 }
 649
 650 int
 651 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 652 {
 653         struct svc_procedure    *proc;
 654         kxdrproc_t              xdr;
 655         __be32                  nfserr;
 656         __be32                  *nfserrp;
 657
 658         dprintk("nfsd_dispatch: vers %d proc %d\n",
 659                                 rqstp->rq_vers, rqstp->rq_proc);
 660         proc = rqstp->rq_procinfo;
 661
 662         /*
 663          * Give the xdr decoder a chance to change this if it wants
 664          * (necessary in the NFSv4.0 compound case)
 665          */
 666         rqstp->rq_cachetype = proc->pc_cachetype;
 667         /* Decode arguments */
 668         xdr = proc->pc_decode;
 669         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 670                         rqstp->rq_argp)) {
 671                 dprintk("nfsd: failed to decode arguments!\n");
 672                 *statp = rpc_garbage_args;
 673                 return 1;
 674         }
 675
 676         /* Check whether we have this call in the cache. */
 677         switch (nfsd_cache_lookup(rqstp)) {
 678         case RC_DROPIT:
 679                 return 0;
 680         case RC_REPLY:
 681                 return 1;
 682         case RC_DOIT:;
 683                 /* do it */
 684         }
 685
 686         /* need to grab the location to store the status, as
 687          * nfsv4 does some encoding while processing
 688          */
 689         nfserrp = rqstp->rq_res.head[0].iov_base
 690                 + rqstp->rq_res.head[0].iov_len;
 691         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 692
 693         /* Now call the procedure handler, and encode NFS status. */
 694         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 695         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 696         if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) {
 697                 dprintk("nfsd: Dropping request; may be revisited later\n");
 698                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 699                 return 0;
 700         }
 701
 702         if (rqstp->rq_proc != 0)
 703                 *nfserrp++ = nfserr;
 704
 705         /* Encode result.
 706          * For NFSv2, additional info is never returned in case of an error.
 707          */
 708         if (!(nfserr && rqstp->rq_vers == 2)) {
 709                 xdr = proc->pc_encode;
 710                 if (xdr && !xdr(rqstp, nfserrp,
 711                                 rqstp->rq_resp)) {
 712                         /* Failed to encode result. Release cache entry */
 713                         dprintk("nfsd: failed to encode result!\n");
 714                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 715                         *statp = rpc_system_err;
 716                         return 1;
 717                 }
 718         }
 719
 720         /* Store reply in cache. */
 721         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
 722         return 1;
 723 }
 724
 725 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 726 {
 727         int ret;
 728         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
 729
 730         mutex_lock(&nfsd_mutex);
 731         if (nn->nfsd_serv == NULL) {
 732                 mutex_unlock(&nfsd_mutex);
 733                 return -ENODEV;
 734         }
 735         /* bump up the psudo refcount while traversing */
 736         svc_get(nn->nfsd_serv);
 737         ret = svc_pool_stats_open(nn->nfsd_serv, file);
 738         mutex_unlock(&nfsd_mutex);
 739         return ret;
 740 }
 741
 742 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 743 {
 744         int ret = seq_release(inode, file);
 745         struct net *net = inode->i_sb->s_fs_info;
 746
 747         mutex_lock(&nfsd_mutex);
 748         /* this function really, really should have been called svc_put() */
 749         nfsd_destroy(net);
 750         mutex_unlock(&nfsd_mutex);
 751         return ret;
 752 }