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 static struct svc_serv_ops nfsd_thread_sv_ops = {
 395         .svo_shutdown           = nfsd_last_thread,
 396         .svo_function           = nfsd,
 397         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 398         .svo_module             = THIS_MODULE,
 399 };
 400
 401 int nfsd_create_serv(struct net *net)
 402 {
 403         int error;
 404         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 405
 406         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 407         if (nn->nfsd_serv) {
 408                 svc_get(nn->nfsd_serv);
 409                 return 0;
 410         }
 411         if (nfsd_max_blksize == 0)
 412                 nfsd_max_blksize = nfsd_get_default_max_blksize();
 413         nfsd_reset_versions();
 414         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
 415                                                 &nfsd_thread_sv_ops);
 416         if (nn->nfsd_serv == NULL)
 417                 return -ENOMEM;
 418
 419         nn->nfsd_serv->sv_maxconn = nn->max_connections;
 420         error = svc_bind(nn->nfsd_serv, net);
 421         if (error < 0) {
 422                 svc_destroy(nn->nfsd_serv);
 423                 return error;
 424         }
 425
 426         set_max_drc();
 427         do_gettimeofday(&nn->nfssvc_boot);              /* record boot time */
 428         return 0;
 429 }
 430
 431 int nfsd_nrpools(struct net *net)
 432 {
 433         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 434
 435         if (nn->nfsd_serv == NULL)
 436                 return 0;
 437         else
 438                 return nn->nfsd_serv->sv_nrpools;
 439 }
 440
 441 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
 442 {
 443         int i = 0;
 444         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 445
 446         if (nn->nfsd_serv != NULL) {
 447                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
 448                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
 449         }
 450
 451         return 0;
 452 }
 453
 454 void nfsd_destroy(struct net *net)
 455 {
 456         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 457         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
 458
 459         if (destroy)
 460                 svc_shutdown_net(nn->nfsd_serv, net);
 461         svc_destroy(nn->nfsd_serv);
 462         if (destroy)
 463                 nn->nfsd_serv = NULL;
 464 }
 465
 466 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 467 {
 468         int i = 0;
 469         int tot = 0;
 470         int err = 0;
 471         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 472
 473         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 474
 475         if (nn->nfsd_serv == NULL || n <= 0)
 476                 return 0;
 477
 478         if (n > nn->nfsd_serv->sv_nrpools)
 479                 n = nn->nfsd_serv->sv_nrpools;
 480
 481         /* enforce a global maximum number of threads */
 482         tot = 0;
 483         for (i = 0; i < n; i++) {
 484                 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
 485                 tot += nthreads[i];
 486         }
 487         if (tot > NFSD_MAXSERVS) {
 488                 /* total too large: scale down requested numbers */
 489                 for (i = 0; i < n && tot > 0; i++) {
 490                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 491                         tot -= (nthreads[i] - new);
 492                         nthreads[i] = new;
 493                 }
 494                 for (i = 0; i < n && tot > 0; i++) {
 495                         nthreads[i]--;
 496                         tot--;
 497                 }
 498         }
 499
 500         /*
 501          * There must always be a thread in pool 0; the admin
 502          * can't shut down NFS completely using pool_threads.
 503          */
 504         if (nthreads[0] == 0)
 505                 nthreads[0] = 1;
 506
 507         /* apply the new numbers */
 508         svc_get(nn->nfsd_serv);
 509         for (i = 0; i < n; i++) {
 510                 err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
 511                                           nthreads[i]);
 512                 if (err)
 513                         break;
 514         }
 515         nfsd_destroy(net);
 516         return err;
 517 }
 518
 519 /*
 520  * Adjust the number of threads and return the new number of threads.
 521  * This is also the function that starts the server if necessary, if
 522  * this is the first time nrservs is nonzero.
 523  */
 524 int
 525 nfsd_svc(int nrservs, struct net *net)
 526 {
 527         int     error;
 528         bool    nfsd_up_before;
 529         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 530
 531         mutex_lock(&nfsd_mutex);
 532         dprintk("nfsd: creating service\n");
 533
 534         nrservs = max(nrservs, 0);
 535         nrservs = min(nrservs, NFSD_MAXSERVS);
 536         error = 0;
 537
 538         if (nrservs == 0 && nn->nfsd_serv == NULL)
 539                 goto out;
 540
 541         error = nfsd_create_serv(net);
 542         if (error)
 543                 goto out;
 544
 545         nfsd_up_before = nn->nfsd_net_up;
 546
 547         error = nfsd_startup_net(nrservs, net);
 548         if (error)
 549                 goto out_destroy;
 550         error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
 551         if (error)
 552                 goto out_shutdown;
 553         /* We are holding a reference to nn->nfsd_serv which
 554          * we don't want to count in the return value,
 555          * so subtract 1
 556          */
 557         error = nn->nfsd_serv->sv_nrthreads - 1;
 558 out_shutdown:
 559         if (error < 0 && !nfsd_up_before)
 560                 nfsd_shutdown_net(net);
 561 out_destroy:
 562         nfsd_destroy(net);              /* Release server */
 563 out:
 564         mutex_unlock(&nfsd_mutex);
 565         return error;
 566 }
 567
 568
 569 /*
 570  * This is the NFS server kernel thread
 571  */
 572 static int
 573 nfsd(void *vrqstp)
 574 {
 575         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 576         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
 577         struct net *net = perm_sock->xpt_net;
 578         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 579         int err;
 580
 581         /* Lock module and set up kernel thread */
 582         mutex_lock(&nfsd_mutex);
 583
 584         /* At this point, the thread shares current->fs
 585          * with the init process. We need to create files with a
 586          * umask of 0 instead of init's umask. */
 587         if (unshare_fs_struct() < 0) {
 588                 printk("Unable to start nfsd thread: out of memory\n");
 589                 goto out;
 590         }
 591
 592         current->fs->umask = 0;
 593
 594         /*
 595          * thread is spawned with all signals set to SIG_IGN, re-enable
 596          * the ones that will bring down the thread
 597          */
 598         allow_signal(SIGKILL);
 599         allow_signal(SIGHUP);
 600         allow_signal(SIGINT);
 601         allow_signal(SIGQUIT);
 602
 603         nfsdstats.th_cnt++;
 604         mutex_unlock(&nfsd_mutex);
 605
 606         set_freezable();
 607
 608         /*
 609          * The main request loop
 610          */
 611         for (;;) {
 612                 /* Update sv_maxconn if it has changed */
 613                 rqstp->rq_server->sv_maxconn = nn->max_connections;
 614
 615                 /*
 616                  * Find a socket with data available and call its
 617                  * recvfrom routine.
 618                  */
 619                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 620                         ;
 621                 if (err == -EINTR)
 622                         break;
 623                 validate_process_creds();
 624                 svc_process(rqstp);
 625                 validate_process_creds();
 626         }
 627
 628         /* Clear signals before calling svc_exit_thread() */
 629         flush_signals(current);
 630
 631         mutex_lock(&nfsd_mutex);
 632         nfsdstats.th_cnt --;
 633
 634 out:
 635         rqstp->rq_server = NULL;
 636
 637         /* Release the thread */
 638         svc_exit_thread(rqstp);
 639
 640         nfsd_destroy(net);
 641
 642         /* Release module */
 643         mutex_unlock(&nfsd_mutex);
 644         module_put_and_exit(0);
 645         return 0;
 646 }
 647
 648 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 649 {
 650         if (nfserr == nfserr_jukebox && vers == 2)
 651                 return nfserr_dropit;
 652         if (nfserr == nfserr_wrongsec && vers < 4)
 653                 return nfserr_acces;
 654         return nfserr;
 655 }
 656
 657 int
 658 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 659 {
 660         struct svc_procedure    *proc;
 661         kxdrproc_t              xdr;
 662         __be32                  nfserr;
 663         __be32                  *nfserrp;
 664
 665         dprintk("nfsd_dispatch: vers %d proc %d\n",
 666                                 rqstp->rq_vers, rqstp->rq_proc);
 667         proc = rqstp->rq_procinfo;
 668
 669         /*
 670          * Give the xdr decoder a chance to change this if it wants
 671          * (necessary in the NFSv4.0 compound case)
 672          */
 673         rqstp->rq_cachetype = proc->pc_cachetype;
 674         /* Decode arguments */
 675         xdr = proc->pc_decode;
 676         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 677                         rqstp->rq_argp)) {
 678                 dprintk("nfsd: failed to decode arguments!\n");
 679                 *statp = rpc_garbage_args;
 680                 return 1;
 681         }
 682
 683         /* Check whether we have this call in the cache. */
 684         switch (nfsd_cache_lookup(rqstp)) {
 685         case RC_DROPIT:
 686                 return 0;
 687         case RC_REPLY:
 688                 return 1;
 689         case RC_DOIT:;
 690                 /* do it */
 691         }
 692
 693         /* need to grab the location to store the status, as
 694          * nfsv4 does some encoding while processing
 695          */
 696         nfserrp = rqstp->rq_res.head[0].iov_base
 697                 + rqstp->rq_res.head[0].iov_len;
 698         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 699
 700         /* Now call the procedure handler, and encode NFS status. */
 701         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 702         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 703         if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) {
 704                 dprintk("nfsd: Dropping request; may be revisited later\n");
 705                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 706                 return 0;
 707         }
 708
 709         if (rqstp->rq_proc != 0)
 710                 *nfserrp++ = nfserr;
 711
 712         /* Encode result.
 713          * For NFSv2, additional info is never returned in case of an error.
 714          */
 715         if (!(nfserr && rqstp->rq_vers == 2)) {
 716                 xdr = proc->pc_encode;
 717                 if (xdr && !xdr(rqstp, nfserrp,
 718                                 rqstp->rq_resp)) {
 719                         /* Failed to encode result. Release cache entry */
 720                         dprintk("nfsd: failed to encode result!\n");
 721                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 722                         *statp = rpc_system_err;
 723                         return 1;
 724                 }
 725         }
 726
 727         /* Store reply in cache. */
 728         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
 729         return 1;
 730 }
 731
 732 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 733 {
 734         int ret;
 735         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
 736
 737         mutex_lock(&nfsd_mutex);
 738         if (nn->nfsd_serv == NULL) {
 739                 mutex_unlock(&nfsd_mutex);
 740                 return -ENODEV;
 741         }
 742         /* bump up the psudo refcount while traversing */
 743         svc_get(nn->nfsd_serv);
 744         ret = svc_pool_stats_open(nn->nfsd_serv, file);
 745         mutex_unlock(&nfsd_mutex);
 746         return ret;
 747 }
 748
 749 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 750 {
 751         int ret = seq_release(inode, file);
 752         struct net *net = inode->i_sb->s_fs_info;
 753
 754         mutex_lock(&nfsd_mutex);
 755         /* this function really, really should have been called svc_put() */
 756         nfsd_destroy(net);
 757         mutex_unlock(&nfsd_mutex);
 758         return ret;
 759 }