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