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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 u32 nfsd_supported_minorversion;
120 
121 int nfsd_vers(int vers, enum vers_op change)
122 {
123         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
124                 return 0;
125         switch(change) {
126         case NFSD_SET:
127                 nfsd_versions[vers] = nfsd_version[vers];
128 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
129                 if (vers < NFSD_ACL_NRVERS)
130                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
131 #endif
132                 break;
133         case NFSD_CLEAR:
134                 nfsd_versions[vers] = NULL;
135 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
136                 if (vers < NFSD_ACL_NRVERS)
137                         nfsd_acl_versions[vers] = NULL;
138 #endif
139                 break;
140         case NFSD_TEST:
141                 return nfsd_versions[vers] != NULL;
142         case NFSD_AVAIL:
143                 return nfsd_version[vers] != NULL;
144         }
145         return 0;
146 }
147 
148 int nfsd_minorversion(u32 minorversion, enum vers_op change)
149 {
150         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
151                 return -1;
152         switch(change) {
153         case NFSD_SET:
154                 nfsd_supported_minorversion = minorversion;
155                 break;
156         case NFSD_CLEAR:
157                 if (minorversion == 0)
158                         return -1;
159                 nfsd_supported_minorversion = minorversion - 1;
160                 break;
161         case NFSD_TEST:
162                 return minorversion <= nfsd_supported_minorversion;
163         case NFSD_AVAIL:
164                 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
165         }
166         return 0;
167 }
168 
169 /*
170  * Maximum number of nfsd processes
171  */
172 #define NFSD_MAXSERVS           8192
173 
174 int nfsd_nrthreads(struct net *net)
175 {
176         int rv = 0;
177         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
178 
179         mutex_lock(&nfsd_mutex);
180         if (nn->nfsd_serv)
181                 rv = nn->nfsd_serv->sv_nrthreads;
182         mutex_unlock(&nfsd_mutex);
183         return rv;
184 }
185 
186 static int nfsd_init_socks(struct net *net)
187 {
188         int error;
189         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
190 
191         if (!list_empty(&nn->nfsd_serv->sv_permsocks))
192                 return 0;
193 
194         error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
195                                         SVC_SOCK_DEFAULTS);
196         if (error < 0)
197                 return error;
198 
199         error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
200                                         SVC_SOCK_DEFAULTS);
201         if (error < 0)
202                 return error;
203 
204         return 0;
205 }
206 
207 static int nfsd_users = 0;
208 
209 static int nfsd_startup_generic(int nrservs)
210 {
211         int ret;
212 
213         if (nfsd_users++)
214                 return 0;
215 
216         /*
217          * Readahead param cache - will no-op if it already exists.
218          * (Note therefore results will be suboptimal if number of
219          * threads is modified after nfsd start.)
220          */
221         ret = nfsd_racache_init(2*nrservs);
222         if (ret)
223                 goto dec_users;
224 
225         ret = nfs4_state_start();
226         if (ret)
227                 goto out_racache;
228         return 0;
229 
230 out_racache:
231         nfsd_racache_shutdown();
232 dec_users:
233         nfsd_users--;
234         return ret;
235 }
236 
237 static void nfsd_shutdown_generic(void)
238 {
239         if (--nfsd_users)
240                 return;
241 
242         nfs4_state_shutdown();
243         nfsd_racache_shutdown();
244 }
245 
246 static int nfsd_startup_net(int nrservs, struct net *net)
247 {
248         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
249         int ret;
250 
251         if (nn->nfsd_net_up)
252                 return 0;
253 
254         ret = nfsd_startup_generic(nrservs);
255         if (ret)
256                 return ret;
257         ret = nfsd_init_socks(net);
258         if (ret)
259                 goto out_socks;
260         ret = lockd_up(net);
261         if (ret)
262                 goto out_socks;
263         ret = nfs4_state_start_net(net);
264         if (ret)
265                 goto out_lockd;
266 
267         nn->nfsd_net_up = true;
268         return 0;
269 
270 out_lockd:
271         lockd_down(net);
272 out_socks:
273         nfsd_shutdown_generic();
274         return ret;
275 }
276 
277 static void nfsd_shutdown_net(struct net *net)
278 {
279         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
280 
281         nfs4_state_shutdown_net(net);
282         lockd_down(net);
283         nn->nfsd_net_up = false;
284         nfsd_shutdown_generic();
285 }
286 
287 static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
288 {
289         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
290 
291         /*
292          * write_ports can create the server without actually starting
293          * any threads--if we get shut down before any threads are
294          * started, then nfsd_last_thread will be run before any of this
295          * other initialization has been done.
296          */
297         if (!nn->nfsd_net_up)
298                 return;
299         nfsd_shutdown_net(net);
300 
301         svc_rpcb_cleanup(serv, net);
302 
303         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
304                             "cache\n");
305         nfsd_export_flush(net);
306 }
307 
308 void nfsd_reset_versions(void)
309 {
310         int found_one = 0;
311         int i;
312 
313         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
314                 if (nfsd_program.pg_vers[i])
315                         found_one = 1;
316         }
317 
318         if (!found_one) {
319                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
320                         nfsd_program.pg_vers[i] = nfsd_version[i];
321 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
322                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
323                         nfsd_acl_program.pg_vers[i] =
324                                 nfsd_acl_version[i];
325 #endif
326         }
327 }
328 
329 /*
330  * Each session guarantees a negotiated per slot memory cache for replies
331  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
332  * NFSv4.1 server might want to use more memory for a DRC than a machine
333  * with mutiple services.
334  *
335  * Impose a hard limit on the number of pages for the DRC which varies
336  * according to the machines free pages. This is of course only a default.
337  *
338  * For now this is a #defined shift which could be under admin control
339  * in the future.
340  */
341 static void set_max_drc(void)
342 {
343         #define NFSD_DRC_SIZE_SHIFT     10
344         nfsd_drc_max_mem = (nr_free_buffer_pages()
345                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
346         nfsd_drc_mem_used = 0;
347         spin_lock_init(&nfsd_drc_lock);
348         dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
349 }
350 
351 static int nfsd_get_default_max_blksize(void)
352 {
353         struct sysinfo i;
354         unsigned long long target;
355         unsigned long ret;
356 
357         si_meminfo(&i);
358         target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
359         /*
360          * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
361          * machines, but only uses 32K on 128M machines.  Bottom out at
362          * 8K on 32M and smaller.  Of course, this is only a default.
363          */
364         target >>= 12;
365 
366         ret = NFSSVC_MAXBLKSIZE;
367         while (ret > target && ret >= 8*1024*2)
368                 ret /= 2;
369         return ret;
370 }
371 
372 int nfsd_create_serv(struct net *net)
373 {
374         int error;
375         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
376 
377         WARN_ON(!mutex_is_locked(&nfsd_mutex));
378         if (nn->nfsd_serv) {
379                 svc_get(nn->nfsd_serv);
380                 return 0;
381         }
382         if (nfsd_max_blksize == 0)
383                 nfsd_max_blksize = nfsd_get_default_max_blksize();
384         nfsd_reset_versions();
385         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
386                                       nfsd_last_thread, nfsd, THIS_MODULE);
387         if (nn->nfsd_serv == NULL)
388                 return -ENOMEM;
389 
390         error = svc_bind(nn->nfsd_serv, net);
391         if (error < 0) {
392                 svc_destroy(nn->nfsd_serv);
393                 return error;
394         }
395 
396         set_max_drc();
397         do_gettimeofday(&nn->nfssvc_boot);              /* record boot time */
398         return 0;
399 }
400 
401 int nfsd_nrpools(struct net *net)
402 {
403         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
404 
405         if (nn->nfsd_serv == NULL)
406                 return 0;
407         else
408                 return nn->nfsd_serv->sv_nrpools;
409 }
410 
411 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
412 {
413         int i = 0;
414         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
415 
416         if (nn->nfsd_serv != NULL) {
417                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
418                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
419         }
420 
421         return 0;
422 }
423 
424 void nfsd_destroy(struct net *net)
425 {
426         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
427         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
428 
429         if (destroy)
430                 svc_shutdown_net(nn->nfsd_serv, net);
431         svc_destroy(nn->nfsd_serv);
432         if (destroy)
433                 nn->nfsd_serv = NULL;
434 }
435 
436 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
437 {
438         int i = 0;
439         int tot = 0;
440         int err = 0;
441         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
442 
443         WARN_ON(!mutex_is_locked(&nfsd_mutex));
444 
445         if (nn->nfsd_serv == NULL || n <= 0)
446                 return 0;
447 
448         if (n > nn->nfsd_serv->sv_nrpools)
449                 n = nn->nfsd_serv->sv_nrpools;
450 
451         /* enforce a global maximum number of threads */
452         tot = 0;
453         for (i = 0; i < n; i++) {
454                 if (nthreads[i] > NFSD_MAXSERVS)
455                         nthreads[i] = NFSD_MAXSERVS;
456                 tot += nthreads[i];
457         }
458         if (tot > NFSD_MAXSERVS) {
459                 /* total too large: scale down requested numbers */
460                 for (i = 0; i < n && tot > 0; i++) {
461                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
462                         tot -= (nthreads[i] - new);
463                         nthreads[i] = new;
464                 }
465                 for (i = 0; i < n && tot > 0; i++) {
466                         nthreads[i]--;
467                         tot--;
468                 }
469         }
470 
471         /*
472          * There must always be a thread in pool 0; the admin
473          * can't shut down NFS completely using pool_threads.
474          */
475         if (nthreads[0] == 0)
476                 nthreads[0] = 1;
477 
478         /* apply the new numbers */
479         svc_get(nn->nfsd_serv);
480         for (i = 0; i < n; i++) {
481                 err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
482                                           nthreads[i]);
483                 if (err)
484                         break;
485         }
486         nfsd_destroy(net);
487         return err;
488 }
489 
490 /*
491  * Adjust the number of threads and return the new number of threads.
492  * This is also the function that starts the server if necessary, if
493  * this is the first time nrservs is nonzero.
494  */
495 int
496 nfsd_svc(int nrservs, struct net *net)
497 {
498         int     error;
499         bool    nfsd_up_before;
500         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
501 
502         mutex_lock(&nfsd_mutex);
503         dprintk("nfsd: creating service\n");
504         if (nrservs <= 0)
505                 nrservs = 0;
506         if (nrservs > NFSD_MAXSERVS)
507                 nrservs = NFSD_MAXSERVS;
508         error = 0;
509         if (nrservs == 0 && nn->nfsd_serv == NULL)
510                 goto out;
511 
512         error = nfsd_create_serv(net);
513         if (error)
514                 goto out;
515 
516         nfsd_up_before = nn->nfsd_net_up;
517 
518         error = nfsd_startup_net(nrservs, net);
519         if (error)
520                 goto out_destroy;
521         error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
522         if (error)
523                 goto out_shutdown;
524         /* We are holding a reference to nn->nfsd_serv which
525          * we don't want to count in the return value,
526          * so subtract 1
527          */
528         error = nn->nfsd_serv->sv_nrthreads - 1;
529 out_shutdown:
530         if (error < 0 && !nfsd_up_before)
531                 nfsd_shutdown_net(net);
532 out_destroy:
533         nfsd_destroy(net);              /* Release server */
534 out:
535         mutex_unlock(&nfsd_mutex);
536         return error;
537 }
538 
539 
540 /*
541  * This is the NFS server kernel thread
542  */
543 static int
544 nfsd(void *vrqstp)
545 {
546         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
547         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
548         struct net *net = perm_sock->xpt_net;
549         int err;
550 
551         /* Lock module and set up kernel thread */
552         mutex_lock(&nfsd_mutex);
553 
554         /* At this point, the thread shares current->fs
555          * with the init process. We need to create files with a
556          * umask of 0 instead of init's umask. */
557         if (unshare_fs_struct() < 0) {
558                 printk("Unable to start nfsd thread: out of memory\n");
559                 goto out;
560         }
561 
562         current->fs->umask = 0;
563 
564         /*
565          * thread is spawned with all signals set to SIG_IGN, re-enable
566          * the ones that will bring down the thread
567          */
568         allow_signal(SIGKILL);
569         allow_signal(SIGHUP);
570         allow_signal(SIGINT);
571         allow_signal(SIGQUIT);
572 
573         nfsdstats.th_cnt++;
574         mutex_unlock(&nfsd_mutex);
575 
576         /*
577          * We want less throttling in balance_dirty_pages() so that nfs to
578          * localhost doesn't cause nfsd to lock up due to all the client's
579          * dirty pages.
580          */
581         current->flags |= PF_LESS_THROTTLE;
582         set_freezable();
583 
584         /*
585          * The main request loop
586          */
587         for (;;) {
588                 /*
589                  * Find a socket with data available and call its
590                  * recvfrom routine.
591                  */
592                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
593                         ;
594                 if (err == -EINTR)
595                         break;
596                 validate_process_creds();
597                 svc_process(rqstp);
598                 validate_process_creds();
599         }
600 
601         /* Clear signals before calling svc_exit_thread() */
602         flush_signals(current);
603 
604         mutex_lock(&nfsd_mutex);
605         nfsdstats.th_cnt --;
606 
607 out:
608         rqstp->rq_server = NULL;
609 
610         /* Release the thread */
611         svc_exit_thread(rqstp);
612 
613         nfsd_destroy(net);
614 
615         /* Release module */
616         mutex_unlock(&nfsd_mutex);
617         module_put_and_exit(0);
618         return 0;
619 }
620 
621 static __be32 map_new_errors(u32 vers, __be32 nfserr)
622 {
623         if (nfserr == nfserr_jukebox && vers == 2)
624                 return nfserr_dropit;
625         if (nfserr == nfserr_wrongsec && vers < 4)
626                 return nfserr_acces;
627         return nfserr;
628 }
629 
630 /*
631  * A write procedure can have a large argument, and a read procedure can
632  * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
633  * reply that can both be larger than a page.  The xdr code has taken
634  * advantage of this assumption to be a sloppy about bounds checking in
635  * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
636  * problem, we enforce these assumptions here:
637  */
638 static bool nfs_request_too_big(struct svc_rqst *rqstp,
639                                 struct svc_procedure *proc)
640 {
641         /*
642          * The ACL code has more careful bounds-checking and is not
643          * susceptible to this problem:
644          */
645         if (rqstp->rq_prog != NFS_PROGRAM)
646                 return false;
647         /*
648          * Ditto NFSv4 (which can in theory have argument and reply both
649          * more than a page):
650          */
651         if (rqstp->rq_vers >= 4)
652                 return false;
653         /* The reply will be small, we're OK: */
654         if (proc->pc_xdrressize > 0 &&
655             proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
656                 return false;
657 
658         return rqstp->rq_arg.len > PAGE_SIZE;
659 }
660 
661 int
662 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
663 {
664         struct svc_procedure    *proc;
665         kxdrproc_t              xdr;
666         __be32                  nfserr;
667         __be32                  *nfserrp;
668 
669         dprintk("nfsd_dispatch: vers %d proc %d\n",
670                                 rqstp->rq_vers, rqstp->rq_proc);
671         proc = rqstp->rq_procinfo;
672 
673         if (nfs_request_too_big(rqstp, proc)) {
674                 dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
675                 *statp = rpc_garbage_args;
676                 return 1;
677         }
678         /*
679          * Give the xdr decoder a chance to change this if it wants
680          * (necessary in the NFSv4.0 compound case)
681          */
682         rqstp->rq_cachetype = proc->pc_cachetype;
683         /* Decode arguments */
684         xdr = proc->pc_decode;
685         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
686                         rqstp->rq_argp)) {
687                 dprintk("nfsd: failed to decode arguments!\n");
688                 *statp = rpc_garbage_args;
689                 return 1;
690         }
691 
692         /* Check whether we have this call in the cache. */
693         switch (nfsd_cache_lookup(rqstp)) {
694         case RC_DROPIT:
695                 return 0;
696         case RC_REPLY:
697                 return 1;
698         case RC_DOIT:;
699                 /* do it */
700         }
701 
702         /* need to grab the location to store the status, as
703          * nfsv4 does some encoding while processing 
704          */
705         nfserrp = rqstp->rq_res.head[0].iov_base
706                 + rqstp->rq_res.head[0].iov_len;
707         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
708 
709         /* Now call the procedure handler, and encode NFS status. */
710         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
711         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
712         if (nfserr == nfserr_dropit || rqstp->rq_dropme) {
713                 dprintk("nfsd: Dropping request; may be revisited later\n");
714                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
715                 return 0;
716         }
717 
718         if (rqstp->rq_proc != 0)
719                 *nfserrp++ = nfserr;
720 
721         /* Encode result.
722          * For NFSv2, additional info is never returned in case of an error.
723          */
724         if (!(nfserr && rqstp->rq_vers == 2)) {
725                 xdr = proc->pc_encode;
726                 if (xdr && !xdr(rqstp, nfserrp,
727                                 rqstp->rq_resp)) {
728                         /* Failed to encode result. Release cache entry */
729                         dprintk("nfsd: failed to encode result!\n");
730                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
731                         *statp = rpc_system_err;
732                         return 1;
733                 }
734         }
735 
736         /* Store reply in cache. */
737         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
738         return 1;
739 }
740 
741 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
742 {
743         int ret;
744         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
745 
746         mutex_lock(&nfsd_mutex);
747         if (nn->nfsd_serv == NULL) {
748                 mutex_unlock(&nfsd_mutex);
749                 return -ENODEV;
750         }
751         /* bump up the psudo refcount while traversing */
752         svc_get(nn->nfsd_serv);
753         ret = svc_pool_stats_open(nn->nfsd_serv, file);
754         mutex_unlock(&nfsd_mutex);
755         return ret;
756 }
757 
758 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
759 {
760         int ret = seq_release(inode, file);
761         struct net *net = inode->i_sb->s_fs_info;
762 
763         mutex_lock(&nfsd_mutex);
764         /* this function really, really should have been called svc_put() */
765         nfsd_destroy(net);
766         mutex_unlock(&nfsd_mutex);
767         return ret;
768 }
769 

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