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