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                 goto dec_users;
 225
 226         ret = nfs4_state_start();
 227         if (ret)
 228                 goto out_racache;
 229         return 0;
 230
 231 out_racache:
 232         nfsd_racache_shutdown();
 233 dec_users:
 234         nfsd_users--;
 235         return ret;
 236 }
 237
 238 static void nfsd_shutdown_generic(void)
 239 {
 240         if (--nfsd_users)
 241                 return;
 242
 243         nfs4_state_shutdown();
 244         nfsd_racache_shutdown();
 245 }
 246
 247 static bool nfsd_needs_lockd(void)
 248 {
 249 #if defined(CONFIG_NFSD_V3)
 250         return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
 251 #else
 252         return (nfsd_versions[2] != NULL);
 253 #endif
 254 }
 255
 256 static int nfsd_startup_net(int nrservs, struct net *net)
 257 {
 258         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 259         int ret;
 260
 261         if (nn->nfsd_net_up)
 262                 return 0;
 263
 264         ret = nfsd_startup_generic(nrservs);
 265         if (ret)
 266                 return ret;
 267         ret = nfsd_init_socks(net);
 268         if (ret)
 269                 goto out_socks;
 270
 271         if (nfsd_needs_lockd() && !nn->lockd_up) {
 272                 ret = lockd_up(net);
 273                 if (ret)
 274                         goto out_socks;
 275                 nn->lockd_up = 1;
 276         }
 277
 278         ret = nfs4_state_start_net(net);
 279         if (ret)
 280                 goto out_lockd;
 281
 282         nn->nfsd_net_up = true;
 283         return 0;
 284
 285 out_lockd:
 286         if (nn->lockd_up) {
 287                 lockd_down(net);
 288                 nn->lockd_up = 0;
 289         }
 290 out_socks:
 291         nfsd_shutdown_generic();
 292         return ret;
 293 }
 294
 295 static void nfsd_shutdown_net(struct net *net)
 296 {
 297         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 298
 299         nfs4_state_shutdown_net(net);
 300         if (nn->lockd_up) {
 301                 lockd_down(net);
 302                 nn->lockd_up = 0;
 303         }
 304         nn->nfsd_net_up = false;
 305         nfsd_shutdown_generic();
 306 }
 307
 308 static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
 309 {
 310         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 311
 312         /*
 313          * write_ports can create the server without actually starting
 314          * any threads--if we get shut down before any threads are
 315          * started, then nfsd_last_thread will be run before any of this
 316          * other initialization has been done.
 317          */
 318         if (!nn->nfsd_net_up)
 319                 return;
 320         nfsd_shutdown_net(net);
 321
 322         svc_rpcb_cleanup(serv, net);
 323
 324         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
 325                             "cache\n");
 326         nfsd_export_flush(net);
 327 }
 328
 329 void nfsd_reset_versions(void)
 330 {
 331         int found_one = 0;
 332         int i;
 333
 334         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 335                 if (nfsd_program.pg_vers[i])
 336                         found_one = 1;
 337         }
 338
 339         if (!found_one) {
 340                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 341                         nfsd_program.pg_vers[i] = nfsd_version[i];
 342 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 343                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 344                         nfsd_acl_program.pg_vers[i] =
 345                                 nfsd_acl_version[i];
 346 #endif
 347         }
 348 }
 349
 350 /*
 351  * Each session guarantees a negotiated per slot memory cache for replies
 352  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 353  * NFSv4.1 server might want to use more memory for a DRC than a machine
 354  * with mutiple services.
 355  *
 356  * Impose a hard limit on the number of pages for the DRC which varies
 357  * according to the machines free pages. This is of course only a default.
 358  *
 359  * For now this is a #defined shift which could be under admin control
 360  * in the future.
 361  */
 362 static void set_max_drc(void)
 363 {
 364         #define NFSD_DRC_SIZE_SHIFT     10
 365         nfsd_drc_max_mem = (nr_free_buffer_pages()
 366                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
 367         nfsd_drc_mem_used = 0;
 368         spin_lock_init(&nfsd_drc_lock);
 369         dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
 370 }
 371
 372 static int nfsd_get_default_max_blksize(void)
 373 {
 374         struct sysinfo i;
 375         unsigned long long target;
 376         unsigned long ret;
 377
 378         si_meminfo(&i);
 379         target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
 380         /*
 381          * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
 382          * machines, but only uses 32K on 128M machines.  Bottom out at
 383          * 8K on 32M and smaller.  Of course, this is only a default.
 384          */
 385         target >>= 12;
 386
 387         ret = NFSSVC_MAXBLKSIZE;
 388         while (ret > target && ret >= 8*1024*2)
 389                 ret /= 2;
 390         return ret;
 391 }
 392
 393 int nfsd_create_serv(struct net *net)
 394 {
 395         int error;
 396         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 397
 398         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 399         if (nn->nfsd_serv) {
 400                 svc_get(nn->nfsd_serv);
 401                 return 0;
 402         }
 403         if (nfsd_max_blksize == 0)
 404                 nfsd_max_blksize = nfsd_get_default_max_blksize();
 405         nfsd_reset_versions();
 406         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
 407                                       nfsd_last_thread, nfsd, THIS_MODULE);
 408         if (nn->nfsd_serv == NULL)
 409                 return -ENOMEM;
 410
 411         nn->nfsd_serv->sv_maxconn = nn->max_connections;
 412         error = svc_bind(nn->nfsd_serv, net);
 413         if (error < 0) {
 414                 svc_destroy(nn->nfsd_serv);
 415                 return error;
 416         }
 417
 418         set_max_drc();
 419         do_gettimeofday(&nn->nfssvc_boot);              /* record boot time */
 420         return 0;
 421 }
 422
 423 int nfsd_nrpools(struct net *net)
 424 {
 425         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 426
 427         if (nn->nfsd_serv == NULL)
 428                 return 0;
 429         else
 430                 return nn->nfsd_serv->sv_nrpools;
 431 }
 432
 433 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
 434 {
 435         int i = 0;
 436         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 437
 438         if (nn->nfsd_serv != NULL) {
 439                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
 440                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
 441         }
 442
 443         return 0;
 444 }
 445
 446 void nfsd_destroy(struct net *net)
 447 {
 448         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 449         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
 450
 451         if (destroy)
 452                 svc_shutdown_net(nn->nfsd_serv, net);
 453         svc_destroy(nn->nfsd_serv);
 454         if (destroy)
 455                 nn->nfsd_serv = NULL;
 456 }
 457
 458 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 459 {
 460         int i = 0;
 461         int tot = 0;
 462         int err = 0;
 463         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 464
 465         WARN_ON(!mutex_is_locked(&nfsd_mutex));
 466
 467         if (nn->nfsd_serv == NULL || n <= 0)
 468                 return 0;
 469
 470         if (n > nn->nfsd_serv->sv_nrpools)
 471                 n = nn->nfsd_serv->sv_nrpools;
 472
 473         /* enforce a global maximum number of threads */
 474         tot = 0;
 475         for (i = 0; i < n; i++) {
 476                 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
 477                 tot += nthreads[i];
 478         }
 479         if (tot > NFSD_MAXSERVS) {
 480                 /* total too large: scale down requested numbers */
 481                 for (i = 0; i < n && tot > 0; i++) {
 482                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 483                         tot -= (nthreads[i] - new);
 484                         nthreads[i] = new;
 485                 }
 486                 for (i = 0; i < n && tot > 0; i++) {
 487                         nthreads[i]--;
 488                         tot--;
 489                 }
 490         }
 491
 492         /*
 493          * There must always be a thread in pool 0; the admin
 494          * can't shut down NFS completely using pool_threads.
 495          */
 496         if (nthreads[0] == 0)
 497                 nthreads[0] = 1;
 498
 499         /* apply the new numbers */
 500         svc_get(nn->nfsd_serv);
 501         for (i = 0; i < n; i++) {
 502                 err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
 503                                           nthreads[i]);
 504                 if (err)
 505                         break;
 506         }
 507         nfsd_destroy(net);
 508         return err;
 509 }
 510
 511 /*
 512  * Adjust the number of threads and return the new number of threads.
 513  * This is also the function that starts the server if necessary, if
 514  * this is the first time nrservs is nonzero.
 515  */
 516 int
 517 nfsd_svc(int nrservs, struct net *net)
 518 {
 519         int     error;
 520         bool    nfsd_up_before;
 521         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 522
 523         mutex_lock(&nfsd_mutex);
 524         dprintk("nfsd: creating service\n");
 525
 526         nrservs = max(nrservs, 0);
 527         nrservs = min(nrservs, NFSD_MAXSERVS);
 528         error = 0;
 529
 530         if (nrservs == 0 && nn->nfsd_serv == NULL)
 531                 goto out;
 532
 533         error = nfsd_create_serv(net);
 534         if (error)
 535                 goto out;
 536
 537         nfsd_up_before = nn->nfsd_net_up;
 538
 539         error = nfsd_startup_net(nrservs, net);
 540         if (error)
 541                 goto out_destroy;
 542         error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
 543         if (error)
 544                 goto out_shutdown;
 545         /* We are holding a reference to nn->nfsd_serv which
 546          * we don't want to count in the return value,
 547          * so subtract 1
 548          */
 549         error = nn->nfsd_serv->sv_nrthreads - 1;
 550 out_shutdown:
 551         if (error < 0 && !nfsd_up_before)
 552                 nfsd_shutdown_net(net);
 553 out_destroy:
 554         nfsd_destroy(net);              /* Release server */
 555 out:
 556         mutex_unlock(&nfsd_mutex);
 557         return error;
 558 }
 559
 560
 561 /*
 562  * This is the NFS server kernel thread
 563  */
 564 static int
 565 nfsd(void *vrqstp)
 566 {
 567         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 568         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
 569         struct net *net = perm_sock->xpt_net;
 570         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 571         int err;
 572
 573         /* Lock module and set up kernel thread */
 574         mutex_lock(&nfsd_mutex);
 575
 576         /* At this point, the thread shares current->fs
 577          * with the init process. We need to create files with a
 578          * umask of 0 instead of init's umask. */
 579         if (unshare_fs_struct() < 0) {
 580                 printk("Unable to start nfsd thread: out of memory\n");
 581                 goto out;
 582         }
 583
 584         current->fs->umask = 0;
 585
 586         /*
 587          * thread is spawned with all signals set to SIG_IGN, re-enable
 588          * the ones that will bring down the thread
 589          */
 590         allow_signal(SIGKILL);
 591         allow_signal(SIGHUP);
 592         allow_signal(SIGINT);
 593         allow_signal(SIGQUIT);
 594
 595         nfsdstats.th_cnt++;
 596         mutex_unlock(&nfsd_mutex);
 597
 598         set_freezable();
 599
 600         /*
 601          * The main request loop
 602          */
 603         for (;;) {
 604                 /* Update sv_maxconn if it has changed */
 605                 rqstp->rq_server->sv_maxconn = nn->max_connections;
 606
 607                 /*
 608                  * Find a socket with data available and call its
 609                  * recvfrom routine.
 610                  */
 611                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 612                         ;
 613                 if (err == -EINTR)
 614                         break;
 615                 validate_process_creds();
 616                 svc_process(rqstp);
 617                 validate_process_creds();
 618         }
 619
 620         /* Clear signals before calling svc_exit_thread() */
 621         flush_signals(current);
 622
 623         mutex_lock(&nfsd_mutex);
 624         nfsdstats.th_cnt --;
 625
 626 out:
 627         rqstp->rq_server = NULL;
 628
 629         /* Release the thread */
 630         svc_exit_thread(rqstp);
 631
 632         nfsd_destroy(net);
 633
 634         /* Release module */
 635         mutex_unlock(&nfsd_mutex);
 636         module_put_and_exit(0);
 637         return 0;
 638 }
 639
 640 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 641 {
 642         if (nfserr == nfserr_jukebox && vers == 2)
 643                 return nfserr_dropit;
 644         if (nfserr == nfserr_wrongsec && vers < 4)
 645                 return nfserr_acces;
 646         return nfserr;
 647 }
 648
 649 int
 650 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 651 {
 652         struct svc_procedure    *proc;
 653         kxdrproc_t              xdr;
 654         __be32                  nfserr;
 655         __be32                  *nfserrp;
 656
 657         dprintk("nfsd_dispatch: vers %d proc %d\n",
 658                                 rqstp->rq_vers, rqstp->rq_proc);
 659         proc = rqstp->rq_procinfo;
 660
 661         /*
 662          * Give the xdr decoder a chance to change this if it wants
 663          * (necessary in the NFSv4.0 compound case)
 664          */
 665         rqstp->rq_cachetype = proc->pc_cachetype;
 666         /* Decode arguments */
 667         xdr = proc->pc_decode;
 668         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 669                         rqstp->rq_argp)) {
 670                 dprintk("nfsd: failed to decode arguments!\n");
 671                 *statp = rpc_garbage_args;
 672                 return 1;
 673         }
 674
 675         /* Check whether we have this call in the cache. */
 676         switch (nfsd_cache_lookup(rqstp)) {
 677         case RC_DROPIT:
 678                 return 0;
 679         case RC_REPLY:
 680                 return 1;
 681         case RC_DOIT:;
 682                 /* do it */
 683         }
 684
 685         /* need to grab the location to store the status, as
 686          * nfsv4 does some encoding while processing
 687          */
 688         nfserrp = rqstp->rq_res.head[0].iov_base
 689                 + rqstp->rq_res.head[0].iov_len;
 690         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 691
 692         /* Now call the procedure handler, and encode NFS status. */
 693         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 694         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 695         if (nfserr == nfserr_dropit || rqstp->rq_dropme) {
 696                 dprintk("nfsd: Dropping request; may be revisited later\n");
 697                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 698                 return 0;
 699         }
 700
 701         if (rqstp->rq_proc != 0)
 702                 *nfserrp++ = nfserr;
 703
 704         /* Encode result.
 705          * For NFSv2, additional info is never returned in case of an error.
 706          */
 707         if (!(nfserr && rqstp->rq_vers == 2)) {
 708                 xdr = proc->pc_encode;
 709                 if (xdr && !xdr(rqstp, nfserrp,
 710                                 rqstp->rq_resp)) {
 711                         /* Failed to encode result. Release cache entry */
 712                         dprintk("nfsd: failed to encode result!\n");
 713                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 714                         *statp = rpc_system_err;
 715                         return 1;
 716                 }
 717         }
 718
 719         /* Store reply in cache. */
 720         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
 721         return 1;
 722 }
 723
 724 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 725 {
 726         int ret;
 727         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
 728
 729         mutex_lock(&nfsd_mutex);
 730         if (nn->nfsd_serv == NULL) {
 731                 mutex_unlock(&nfsd_mutex);
 732                 return -ENODEV;
 733         }
 734         /* bump up the psudo refcount while traversing */
 735         svc_get(nn->nfsd_serv);
 736         ret = svc_pool_stats_open(nn->nfsd_serv, file);
 737         mutex_unlock(&nfsd_mutex);
 738         return ret;
 739 }
 740
 741 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 742 {
 743         int ret = seq_release(inode, file);
 744         struct net *net = inode->i_sb->s_fs_info;
 745
 746         mutex_lock(&nfsd_mutex);
 747         /* this function really, really should have been called svc_put() */
 748         nfsd_destroy(net);
 749         mutex_unlock(&nfsd_mutex);
 750         return ret;
 751 }