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TOMOYO Linux Cross Reference
Linux/fs/nfsd/nfssvc.c

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  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             change != NFSD_AVAIL)
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 i;
333 
334         for (i = 0; i < NFSD_NRVERS; i++)
335                 if (nfsd_vers(i, NFSD_TEST))
336                         return;
337 
338         for (i = 0; i < NFSD_NRVERS; i++)
339                 if (i != 4)
340                         nfsd_vers(i, NFSD_SET);
341                 else {
342                         int minor = 0;
343                         while (nfsd_minorversion(minor, NFSD_SET) >= 0)
344                                 minor++;
345                 }
346 }
347 
348 /*
349  * Each session guarantees a negotiated per slot memory cache for replies
350  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
351  * NFSv4.1 server might want to use more memory for a DRC than a machine
352  * with mutiple services.
353  *
354  * Impose a hard limit on the number of pages for the DRC which varies
355  * according to the machines free pages. This is of course only a default.
356  *
357  * For now this is a #defined shift which could be under admin control
358  * in the future.
359  */
360 static void set_max_drc(void)
361 {
362         #define NFSD_DRC_SIZE_SHIFT     10
363         nfsd_drc_max_mem = (nr_free_buffer_pages()
364                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
365         nfsd_drc_mem_used = 0;
366         spin_lock_init(&nfsd_drc_lock);
367         dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
368 }
369 
370 static int nfsd_get_default_max_blksize(void)
371 {
372         struct sysinfo i;
373         unsigned long long target;
374         unsigned long ret;
375 
376         si_meminfo(&i);
377         target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
378         /*
379          * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
380          * machines, but only uses 32K on 128M machines.  Bottom out at
381          * 8K on 32M and smaller.  Of course, this is only a default.
382          */
383         target >>= 12;
384 
385         ret = NFSSVC_MAXBLKSIZE;
386         while (ret > target && ret >= 8*1024*2)
387                 ret /= 2;
388         return ret;
389 }
390 
391 int nfsd_create_serv(struct net *net)
392 {
393         int error;
394         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
395 
396         WARN_ON(!mutex_is_locked(&nfsd_mutex));
397         if (nn->nfsd_serv) {
398                 svc_get(nn->nfsd_serv);
399                 return 0;
400         }
401         if (nfsd_max_blksize == 0)
402                 nfsd_max_blksize = nfsd_get_default_max_blksize();
403         nfsd_reset_versions();
404         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
405                                       nfsd_last_thread, nfsd, THIS_MODULE);
406         if (nn->nfsd_serv == NULL)
407                 return -ENOMEM;
408 
409         nn->nfsd_serv->sv_maxconn = nn->max_connections;
410         error = svc_bind(nn->nfsd_serv, net);
411         if (error < 0) {
412                 svc_destroy(nn->nfsd_serv);
413                 return error;
414         }
415 
416         set_max_drc();
417         do_gettimeofday(&nn->nfssvc_boot);              /* record boot time */
418         return 0;
419 }
420 
421 int nfsd_nrpools(struct net *net)
422 {
423         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
424 
425         if (nn->nfsd_serv == NULL)
426                 return 0;
427         else
428                 return nn->nfsd_serv->sv_nrpools;
429 }
430 
431 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
432 {
433         int i = 0;
434         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
435 
436         if (nn->nfsd_serv != NULL) {
437                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
438                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
439         }
440 
441         return 0;
442 }
443 
444 void nfsd_destroy(struct net *net)
445 {
446         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
447         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
448 
449         if (destroy)
450                 svc_shutdown_net(nn->nfsd_serv, net);
451         svc_destroy(nn->nfsd_serv);
452         if (destroy)
453                 nn->nfsd_serv = NULL;
454 }
455 
456 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
457 {
458         int i = 0;
459         int tot = 0;
460         int err = 0;
461         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
462 
463         WARN_ON(!mutex_is_locked(&nfsd_mutex));
464 
465         if (nn->nfsd_serv == NULL || n <= 0)
466                 return 0;
467 
468         if (n > nn->nfsd_serv->sv_nrpools)
469                 n = nn->nfsd_serv->sv_nrpools;
470 
471         /* enforce a global maximum number of threads */
472         tot = 0;
473         for (i = 0; i < n; i++) {
474                 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
475                 tot += nthreads[i];
476         }
477         if (tot > NFSD_MAXSERVS) {
478                 /* total too large: scale down requested numbers */
479                 for (i = 0; i < n && tot > 0; i++) {
480                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
481                         tot -= (nthreads[i] - new);
482                         nthreads[i] = new;
483                 }
484                 for (i = 0; i < n && tot > 0; i++) {
485                         nthreads[i]--;
486                         tot--;
487                 }
488         }
489 
490         /*
491          * There must always be a thread in pool 0; the admin
492          * can't shut down NFS completely using pool_threads.
493          */
494         if (nthreads[0] == 0)
495                 nthreads[0] = 1;
496 
497         /* apply the new numbers */
498         svc_get(nn->nfsd_serv);
499         for (i = 0; i < n; i++) {
500                 err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
501                                           nthreads[i]);
502                 if (err)
503                         break;
504         }
505         nfsd_destroy(net);
506         return err;
507 }
508 
509 /*
510  * Adjust the number of threads and return the new number of threads.
511  * This is also the function that starts the server if necessary, if
512  * this is the first time nrservs is nonzero.
513  */
514 int
515 nfsd_svc(int nrservs, struct net *net)
516 {
517         int     error;
518         bool    nfsd_up_before;
519         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
520 
521         mutex_lock(&nfsd_mutex);
522         dprintk("nfsd: creating service\n");
523 
524         nrservs = max(nrservs, 0);
525         nrservs = min(nrservs, NFSD_MAXSERVS);
526         error = 0;
527 
528         if (nrservs == 0 && nn->nfsd_serv == NULL)
529                 goto out;
530 
531         error = nfsd_create_serv(net);
532         if (error)
533                 goto out;
534 
535         nfsd_up_before = nn->nfsd_net_up;
536 
537         error = nfsd_startup_net(nrservs, net);
538         if (error)
539                 goto out_destroy;
540         error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
541         if (error)
542                 goto out_shutdown;
543         /* We are holding a reference to nn->nfsd_serv which
544          * we don't want to count in the return value,
545          * so subtract 1
546          */
547         error = nn->nfsd_serv->sv_nrthreads - 1;
548 out_shutdown:
549         if (error < 0 && !nfsd_up_before)
550                 nfsd_shutdown_net(net);
551 out_destroy:
552         nfsd_destroy(net);              /* Release server */
553 out:
554         mutex_unlock(&nfsd_mutex);
555         return error;
556 }
557 
558 
559 /*
560  * This is the NFS server kernel thread
561  */
562 static int
563 nfsd(void *vrqstp)
564 {
565         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
566         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
567         struct net *net = perm_sock->xpt_net;
568         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
569         int err;
570 
571         /* Lock module and set up kernel thread */
572         mutex_lock(&nfsd_mutex);
573 
574         /* At this point, the thread shares current->fs
575          * with the init process. We need to create files with a
576          * umask of 0 instead of init's umask. */
577         if (unshare_fs_struct() < 0) {
578                 printk("Unable to start nfsd thread: out of memory\n");
579                 goto out;
580         }
581 
582         current->fs->umask = 0;
583 
584         /*
585          * thread is spawned with all signals set to SIG_IGN, re-enable
586          * the ones that will bring down the thread
587          */
588         allow_signal(SIGKILL);
589         allow_signal(SIGHUP);
590         allow_signal(SIGINT);
591         allow_signal(SIGQUIT);
592 
593         nfsdstats.th_cnt++;
594         mutex_unlock(&nfsd_mutex);
595 
596         set_freezable();
597 
598         /*
599          * The main request loop
600          */
601         for (;;) {
602                 /* Update sv_maxconn if it has changed */
603                 rqstp->rq_server->sv_maxconn = nn->max_connections;
604 
605                 /*
606                  * Find a socket with data available and call its
607                  * recvfrom routine.
608                  */
609                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
610                         ;
611                 if (err == -EINTR)
612                         break;
613                 validate_process_creds();
614                 svc_process(rqstp);
615                 validate_process_creds();
616         }
617 
618         /* Clear signals before calling svc_exit_thread() */
619         flush_signals(current);
620 
621         mutex_lock(&nfsd_mutex);
622         nfsdstats.th_cnt --;
623 
624 out:
625         rqstp->rq_server = NULL;
626 
627         /* Release the thread */
628         svc_exit_thread(rqstp);
629 
630         nfsd_destroy(net);
631 
632         /* Release module */
633         mutex_unlock(&nfsd_mutex);
634         module_put_and_exit(0);
635         return 0;
636 }
637 
638 static __be32 map_new_errors(u32 vers, __be32 nfserr)
639 {
640         if (nfserr == nfserr_jukebox && vers == 2)
641                 return nfserr_dropit;
642         if (nfserr == nfserr_wrongsec && vers < 4)
643                 return nfserr_acces;
644         return nfserr;
645 }
646 
647 /*
648  * A write procedure can have a large argument, and a read procedure can
649  * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
650  * reply that can both be larger than a page.  The xdr code has taken
651  * advantage of this assumption to be a sloppy about bounds checking in
652  * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
653  * problem, we enforce these assumptions here:
654  */
655 static bool nfs_request_too_big(struct svc_rqst *rqstp,
656                                 struct svc_procedure *proc)
657 {
658         /*
659          * The ACL code has more careful bounds-checking and is not
660          * susceptible to this problem:
661          */
662         if (rqstp->rq_prog != NFS_PROGRAM)
663                 return false;
664         /*
665          * Ditto NFSv4 (which can in theory have argument and reply both
666          * more than a page):
667          */
668         if (rqstp->rq_vers >= 4)
669                 return false;
670         /* The reply will be small, we're OK: */
671         if (proc->pc_xdrressize > 0 &&
672             proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
673                 return false;
674 
675         return rqstp->rq_arg.len > PAGE_SIZE;
676 }
677 
678 int
679 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
680 {
681         struct svc_procedure    *proc;
682         kxdrproc_t              xdr;
683         __be32                  nfserr;
684         __be32                  *nfserrp;
685 
686         dprintk("nfsd_dispatch: vers %d proc %d\n",
687                                 rqstp->rq_vers, rqstp->rq_proc);
688         proc = rqstp->rq_procinfo;
689 
690         if (nfs_request_too_big(rqstp, proc)) {
691                 dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
692                 *statp = rpc_garbage_args;
693                 return 1;
694         }
695         /*
696          * Give the xdr decoder a chance to change this if it wants
697          * (necessary in the NFSv4.0 compound case)
698          */
699         rqstp->rq_cachetype = proc->pc_cachetype;
700         /* Decode arguments */
701         xdr = proc->pc_decode;
702         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
703                         rqstp->rq_argp)) {
704                 dprintk("nfsd: failed to decode arguments!\n");
705                 *statp = rpc_garbage_args;
706                 return 1;
707         }
708 
709         /* Check whether we have this call in the cache. */
710         switch (nfsd_cache_lookup(rqstp)) {
711         case RC_DROPIT:
712                 return 0;
713         case RC_REPLY:
714                 return 1;
715         case RC_DOIT:;
716                 /* do it */
717         }
718 
719         /* need to grab the location to store the status, as
720          * nfsv4 does some encoding while processing 
721          */
722         nfserrp = rqstp->rq_res.head[0].iov_base
723                 + rqstp->rq_res.head[0].iov_len;
724         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
725 
726         /* Now call the procedure handler, and encode NFS status. */
727         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
728         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
729         if (nfserr == nfserr_dropit || rqstp->rq_dropme) {
730                 dprintk("nfsd: Dropping request; may be revisited later\n");
731                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
732                 return 0;
733         }
734 
735         if (rqstp->rq_proc != 0)
736                 *nfserrp++ = nfserr;
737 
738         /* Encode result.
739          * For NFSv2, additional info is never returned in case of an error.
740          */
741         if (!(nfserr && rqstp->rq_vers == 2)) {
742                 xdr = proc->pc_encode;
743                 if (xdr && !xdr(rqstp, nfserrp,
744                                 rqstp->rq_resp)) {
745                         /* Failed to encode result. Release cache entry */
746                         dprintk("nfsd: failed to encode result!\n");
747                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
748                         *statp = rpc_system_err;
749                         return 1;
750                 }
751         }
752 
753         /* Store reply in cache. */
754         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
755         return 1;
756 }
757 
758 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
759 {
760         int ret;
761         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
762 
763         mutex_lock(&nfsd_mutex);
764         if (nn->nfsd_serv == NULL) {
765                 mutex_unlock(&nfsd_mutex);
766                 return -ENODEV;
767         }
768         /* bump up the psudo refcount while traversing */
769         svc_get(nn->nfsd_serv);
770         ret = svc_pool_stats_open(nn->nfsd_serv, file);
771         mutex_unlock(&nfsd_mutex);
772         return ret;
773 }
774 
775 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
776 {
777         int ret = seq_release(inode, file);
778         struct net *net = inode->i_sb->s_fs_info;
779 
780         mutex_lock(&nfsd_mutex);
781         /* this function really, really should have been called svc_put() */
782         nfsd_destroy(net);
783         mutex_unlock(&nfsd_mutex);
784         return ret;
785 }
786 

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