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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/sunrpc/svc_xprt.h>
 18 #include <linux/lockd/bind.h>
 19 #include <linux/nfsacl.h>
 20 #include <linux/seq_file.h>
 21 #include <linux/inetdevice.h>
 22 #include <net/addrconf.h>
 23 #include <net/ipv6.h>
 24 #include <net/net_namespace.h>
 25 #include "nfsd.h"
 26 #include "cache.h"
 27 #include "vfs.h"
 28 #include "netns.h"
 29 
 30 #define NFSDDBG_FACILITY        NFSDDBG_SVC
 31 
 32 extern struct svc_program       nfsd_program;
 33 static int                      nfsd(void *vrqstp);
 34 
 35 /*
 36  * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members
 37  * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
 38  * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
 39  *
 40  * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a
 41  * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
 42  * of nfsd threads must exist and each must listed in ->sp_all_threads in each
 43  * entry of ->sv_pools[].
 44  *
 45  * Transitions of the thread count between zero and non-zero are of particular
 46  * interest since the svc_serv needs to be created and initialized at that
 47  * point, or freed.
 48  *
 49  * Finally, the nfsd_mutex also protects some of the global variables that are
 50  * accessed when nfsd starts and that are settable via the write_* routines in
 51  * nfsctl.c. In particular:
 52  *
 53  *      user_recovery_dirname
 54  *      user_lease_time
 55  *      nfsd_versions
 56  */
 57 DEFINE_MUTEX(nfsd_mutex);
 58 
 59 /*
 60  * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
 61  * nfsd_drc_max_pages limits the total amount of memory available for
 62  * version 4.1 DRC caches.
 63  * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
 64  */
 65 spinlock_t      nfsd_drc_lock;
 66 unsigned long   nfsd_drc_max_mem;
 67 unsigned long   nfsd_drc_mem_used;
 68 
 69 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 70 static struct svc_stat  nfsd_acl_svcstats;
 71 static struct svc_version *     nfsd_acl_version[] = {
 72         [2] = &nfsd_acl_version2,
 73         [3] = &nfsd_acl_version3,
 74 };
 75 
 76 #define NFSD_ACL_MINVERS            2
 77 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
 78 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
 79 
 80 static struct svc_program       nfsd_acl_program = {
 81         .pg_prog                = NFS_ACL_PROGRAM,
 82         .pg_nvers               = NFSD_ACL_NRVERS,
 83         .pg_vers                = nfsd_acl_versions,
 84         .pg_name                = "nfsacl",
 85         .pg_class               = "nfsd",
 86         .pg_stats               = &nfsd_acl_svcstats,
 87         .pg_authenticate        = &svc_set_client,
 88 };
 89 
 90 static struct svc_stat  nfsd_acl_svcstats = {
 91         .program        = &nfsd_acl_program,
 92 };
 93 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
 94 
 95 static struct svc_version *     nfsd_version[] = {
 96         [2] = &nfsd_version2,
 97 #if defined(CONFIG_NFSD_V3)
 98         [3] = &nfsd_version3,
 99 #endif
100 #if defined(CONFIG_NFSD_V4)
101         [4] = &nfsd_version4,
102 #endif
103 };
104 
105 #define NFSD_MINVERS            2
106 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
107 static struct svc_version *nfsd_versions[NFSD_NRVERS];
108 
109 struct svc_program              nfsd_program = {
110 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
111         .pg_next                = &nfsd_acl_program,
112 #endif
113         .pg_prog                = NFS_PROGRAM,          /* program number */
114         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
115         .pg_vers                = nfsd_versions,        /* version table */
116         .pg_name                = "nfsd",               /* program name */
117         .pg_class               = "nfsd",               /* authentication class */
118         .pg_stats               = &nfsd_svcstats,       /* version table */
119         .pg_authenticate        = &svc_set_client,      /* export authentication */
120 
121 };
122 
123 static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = {
124         [0] = 1,
125         [1] = 1,
126         [2] = 1,
127 };
128 
129 int nfsd_vers(int vers, enum vers_op change)
130 {
131         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
132                 return 0;
133         switch(change) {
134         case NFSD_SET:
135                 nfsd_versions[vers] = nfsd_version[vers];
136 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
137                 if (vers < NFSD_ACL_NRVERS)
138                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
139 #endif
140                 break;
141         case NFSD_CLEAR:
142                 nfsd_versions[vers] = NULL;
143 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
144                 if (vers < NFSD_ACL_NRVERS)
145                         nfsd_acl_versions[vers] = NULL;
146 #endif
147                 break;
148         case NFSD_TEST:
149                 return nfsd_versions[vers] != NULL;
150         case NFSD_AVAIL:
151                 return nfsd_version[vers] != NULL;
152         }
153         return 0;
154 }
155 
156 int nfsd_minorversion(u32 minorversion, enum vers_op change)
157 {
158         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
159                 return -1;
160         switch(change) {
161         case NFSD_SET:
162                 nfsd_supported_minorversions[minorversion] = true;
163                 break;
164         case NFSD_CLEAR:
165                 nfsd_supported_minorversions[minorversion] = false;
166                 break;
167         case NFSD_TEST:
168                 return nfsd_supported_minorversions[minorversion];
169         case NFSD_AVAIL:
170                 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
171         }
172         return 0;
173 }
174 
175 /*
176  * Maximum number of nfsd processes
177  */
178 #define NFSD_MAXSERVS           8192
179 
180 int nfsd_nrthreads(struct net *net)
181 {
182         int rv = 0;
183         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
184 
185         mutex_lock(&nfsd_mutex);
186         if (nn->nfsd_serv)
187                 rv = nn->nfsd_serv->sv_nrthreads;
188         mutex_unlock(&nfsd_mutex);
189         return rv;
190 }
191 
192 static int nfsd_init_socks(struct net *net)
193 {
194         int error;
195         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
196 
197         if (!list_empty(&nn->nfsd_serv->sv_permsocks))
198                 return 0;
199 
200         error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
201                                         SVC_SOCK_DEFAULTS);
202         if (error < 0)
203                 return error;
204 
205         error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
206                                         SVC_SOCK_DEFAULTS);
207         if (error < 0)
208                 return error;
209 
210         return 0;
211 }
212 
213 static int nfsd_users = 0;
214 
215 static int nfsd_startup_generic(int nrservs)
216 {
217         int ret;
218 
219         if (nfsd_users++)
220                 return 0;
221 
222         /*
223          * Readahead param cache - will no-op if it already exists.
224          * (Note therefore results will be suboptimal if number of
225          * threads is modified after nfsd start.)
226          */
227         ret = nfsd_racache_init(2*nrservs);
228         if (ret)
229                 goto dec_users;
230 
231         ret = nfs4_state_start();
232         if (ret)
233                 goto out_racache;
234         return 0;
235 
236 out_racache:
237         nfsd_racache_shutdown();
238 dec_users:
239         nfsd_users--;
240         return ret;
241 }
242 
243 static void nfsd_shutdown_generic(void)
244 {
245         if (--nfsd_users)
246                 return;
247 
248         nfs4_state_shutdown();
249         nfsd_racache_shutdown();
250 }
251 
252 static bool nfsd_needs_lockd(void)
253 {
254 #if defined(CONFIG_NFSD_V3)
255         return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
256 #else
257         return (nfsd_versions[2] != NULL);
258 #endif
259 }
260 
261 static int nfsd_startup_net(int nrservs, struct net *net)
262 {
263         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
264         int ret;
265 
266         if (nn->nfsd_net_up)
267                 return 0;
268 
269         ret = nfsd_startup_generic(nrservs);
270         if (ret)
271                 return ret;
272         ret = nfsd_init_socks(net);
273         if (ret)
274                 goto out_socks;
275 
276         if (nfsd_needs_lockd() && !nn->lockd_up) {
277                 ret = lockd_up(net);
278                 if (ret)
279                         goto out_socks;
280                 nn->lockd_up = 1;
281         }
282 
283         ret = nfs4_state_start_net(net);
284         if (ret)
285                 goto out_lockd;
286 
287         nn->nfsd_net_up = true;
288         return 0;
289 
290 out_lockd:
291         if (nn->lockd_up) {
292                 lockd_down(net);
293                 nn->lockd_up = 0;
294         }
295 out_socks:
296         nfsd_shutdown_generic();
297         return ret;
298 }
299 
300 static void nfsd_shutdown_net(struct net *net)
301 {
302         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
303 
304         nfs4_state_shutdown_net(net);
305         if (nn->lockd_up) {
306                 lockd_down(net);
307                 nn->lockd_up = 0;
308         }
309         nn->nfsd_net_up = false;
310         nfsd_shutdown_generic();
311 }
312 
313 static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
314         void *ptr)
315 {
316         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
317         struct net_device *dev = ifa->ifa_dev->dev;
318         struct net *net = dev_net(dev);
319         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
320         struct sockaddr_in sin;
321 
322         if (event != NETDEV_DOWN)
323                 goto out;
324 
325         if (nn->nfsd_serv) {
326                 dprintk("nfsd_inetaddr_event: removed %pI4\n", &ifa->ifa_local);
327                 sin.sin_family = AF_INET;
328                 sin.sin_addr.s_addr = ifa->ifa_local;
329                 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin);
330         }
331 
332 out:
333         return NOTIFY_DONE;
334 }
335 
336 static struct notifier_block nfsd_inetaddr_notifier = {
337         .notifier_call = nfsd_inetaddr_event,
338 };
339 
340 #if IS_ENABLED(CONFIG_IPV6)
341 static int nfsd_inet6addr_event(struct notifier_block *this,
342         unsigned long event, void *ptr)
343 {
344         struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
345         struct net_device *dev = ifa->idev->dev;
346         struct net *net = dev_net(dev);
347         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
348         struct sockaddr_in6 sin6;
349 
350         if (event != NETDEV_DOWN)
351                 goto out;
352 
353         if (nn->nfsd_serv) {
354                 dprintk("nfsd_inet6addr_event: removed %pI6\n", &ifa->addr);
355                 sin6.sin6_family = AF_INET6;
356                 sin6.sin6_addr = ifa->addr;
357                 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6);
358         }
359 
360 out:
361         return NOTIFY_DONE;
362 }
363 
364 static struct notifier_block nfsd_inet6addr_notifier = {
365         .notifier_call = nfsd_inet6addr_event,
366 };
367 #endif
368 
369 /* Only used under nfsd_mutex, so this atomic may be overkill: */
370 static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
371 
372 static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
373 {
374         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
375 
376         /* check if the notifier still has clients */
377         if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
378                 unregister_inetaddr_notifier(&nfsd_inetaddr_notifier);
379 #if IS_ENABLED(CONFIG_IPV6)
380                 unregister_inet6addr_notifier(&nfsd_inet6addr_notifier);
381 #endif
382         }
383 
384         /*
385          * write_ports can create the server without actually starting
386          * any threads--if we get shut down before any threads are
387          * started, then nfsd_last_thread will be run before any of this
388          * other initialization has been done except the rpcb information.
389          */
390         svc_rpcb_cleanup(serv, net);
391         if (!nn->nfsd_net_up)
392                 return;
393 
394         nfsd_shutdown_net(net);
395         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
396                             "cache\n");
397         nfsd_export_flush(net);
398 }
399 
400 void nfsd_reset_versions(void)
401 {
402         int found_one = 0;
403         int i;
404 
405         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
406                 if (nfsd_program.pg_vers[i])
407                         found_one = 1;
408         }
409 
410         if (!found_one) {
411                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
412                         nfsd_program.pg_vers[i] = nfsd_version[i];
413 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
414                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
415                         nfsd_acl_program.pg_vers[i] =
416                                 nfsd_acl_version[i];
417 #endif
418         }
419 }
420 
421 /*
422  * Each session guarantees a negotiated per slot memory cache for replies
423  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
424  * NFSv4.1 server might want to use more memory for a DRC than a machine
425  * with mutiple services.
426  *
427  * Impose a hard limit on the number of pages for the DRC which varies
428  * according to the machines free pages. This is of course only a default.
429  *
430  * For now this is a #defined shift which could be under admin control
431  * in the future.
432  */
433 static void set_max_drc(void)
434 {
435         #define NFSD_DRC_SIZE_SHIFT     10
436         nfsd_drc_max_mem = (nr_free_buffer_pages()
437                                         >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
438         nfsd_drc_mem_used = 0;
439         spin_lock_init(&nfsd_drc_lock);
440         dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
441 }
442 
443 static int nfsd_get_default_max_blksize(void)
444 {
445         struct sysinfo i;
446         unsigned long long target;
447         unsigned long ret;
448 
449         si_meminfo(&i);
450         target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
451         /*
452          * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
453          * machines, but only uses 32K on 128M machines.  Bottom out at
454          * 8K on 32M and smaller.  Of course, this is only a default.
455          */
456         target >>= 12;
457 
458         ret = NFSSVC_MAXBLKSIZE;
459         while (ret > target && ret >= 8*1024*2)
460                 ret /= 2;
461         return ret;
462 }
463 
464 static struct svc_serv_ops nfsd_thread_sv_ops = {
465         .svo_shutdown           = nfsd_last_thread,
466         .svo_function           = nfsd,
467         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
468         .svo_setup              = svc_set_num_threads,
469         .svo_module             = THIS_MODULE,
470 };
471 
472 int nfsd_create_serv(struct net *net)
473 {
474         int error;
475         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
476 
477         WARN_ON(!mutex_is_locked(&nfsd_mutex));
478         if (nn->nfsd_serv) {
479                 svc_get(nn->nfsd_serv);
480                 return 0;
481         }
482         if (nfsd_max_blksize == 0)
483                 nfsd_max_blksize = nfsd_get_default_max_blksize();
484         nfsd_reset_versions();
485         nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
486                                                 &nfsd_thread_sv_ops);
487         if (nn->nfsd_serv == NULL)
488                 return -ENOMEM;
489 
490         nn->nfsd_serv->sv_maxconn = nn->max_connections;
491         error = svc_bind(nn->nfsd_serv, net);
492         if (error < 0) {
493                 svc_destroy(nn->nfsd_serv);
494                 return error;
495         }
496 
497         set_max_drc();
498         /* check if the notifier is already set */
499         if (atomic_inc_return(&nfsd_notifier_refcount) == 1) {
500                 register_inetaddr_notifier(&nfsd_inetaddr_notifier);
501 #if IS_ENABLED(CONFIG_IPV6)
502                 register_inet6addr_notifier(&nfsd_inet6addr_notifier);
503 #endif
504         }
505         do_gettimeofday(&nn->nfssvc_boot);              /* record boot time */
506         return 0;
507 }
508 
509 int nfsd_nrpools(struct net *net)
510 {
511         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
512 
513         if (nn->nfsd_serv == NULL)
514                 return 0;
515         else
516                 return nn->nfsd_serv->sv_nrpools;
517 }
518 
519 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
520 {
521         int i = 0;
522         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
523 
524         if (nn->nfsd_serv != NULL) {
525                 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
526                         nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
527         }
528 
529         return 0;
530 }
531 
532 void nfsd_destroy(struct net *net)
533 {
534         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
535         int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
536 
537         if (destroy)
538                 svc_shutdown_net(nn->nfsd_serv, net);
539         svc_destroy(nn->nfsd_serv);
540         if (destroy)
541                 nn->nfsd_serv = NULL;
542 }
543 
544 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
545 {
546         int i = 0;
547         int tot = 0;
548         int err = 0;
549         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
550 
551         WARN_ON(!mutex_is_locked(&nfsd_mutex));
552 
553         if (nn->nfsd_serv == NULL || n <= 0)
554                 return 0;
555 
556         if (n > nn->nfsd_serv->sv_nrpools)
557                 n = nn->nfsd_serv->sv_nrpools;
558 
559         /* enforce a global maximum number of threads */
560         tot = 0;
561         for (i = 0; i < n; i++) {
562                 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
563                 tot += nthreads[i];
564         }
565         if (tot > NFSD_MAXSERVS) {
566                 /* total too large: scale down requested numbers */
567                 for (i = 0; i < n && tot > 0; i++) {
568                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
569                         tot -= (nthreads[i] - new);
570                         nthreads[i] = new;
571                 }
572                 for (i = 0; i < n && tot > 0; i++) {
573                         nthreads[i]--;
574                         tot--;
575                 }
576         }
577 
578         /*
579          * There must always be a thread in pool 0; the admin
580          * can't shut down NFS completely using pool_threads.
581          */
582         if (nthreads[0] == 0)
583                 nthreads[0] = 1;
584 
585         /* apply the new numbers */
586         svc_get(nn->nfsd_serv);
587         for (i = 0; i < n; i++) {
588                 err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
589                                 &nn->nfsd_serv->sv_pools[i], nthreads[i]);
590                 if (err)
591                         break;
592         }
593         nfsd_destroy(net);
594         return err;
595 }
596 
597 /*
598  * Adjust the number of threads and return the new number of threads.
599  * This is also the function that starts the server if necessary, if
600  * this is the first time nrservs is nonzero.
601  */
602 int
603 nfsd_svc(int nrservs, struct net *net)
604 {
605         int     error;
606         bool    nfsd_up_before;
607         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
608 
609         mutex_lock(&nfsd_mutex);
610         dprintk("nfsd: creating service\n");
611 
612         nrservs = max(nrservs, 0);
613         nrservs = min(nrservs, NFSD_MAXSERVS);
614         error = 0;
615 
616         if (nrservs == 0 && nn->nfsd_serv == NULL)
617                 goto out;
618 
619         error = nfsd_create_serv(net);
620         if (error)
621                 goto out;
622 
623         nfsd_up_before = nn->nfsd_net_up;
624 
625         error = nfsd_startup_net(nrservs, net);
626         if (error)
627                 goto out_destroy;
628         error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
629                         NULL, nrservs);
630         if (error)
631                 goto out_shutdown;
632         /* We are holding a reference to nn->nfsd_serv which
633          * we don't want to count in the return value,
634          * so subtract 1
635          */
636         error = nn->nfsd_serv->sv_nrthreads - 1;
637 out_shutdown:
638         if (error < 0 && !nfsd_up_before)
639                 nfsd_shutdown_net(net);
640 out_destroy:
641         nfsd_destroy(net);              /* Release server */
642 out:
643         mutex_unlock(&nfsd_mutex);
644         return error;
645 }
646 
647 
648 /*
649  * This is the NFS server kernel thread
650  */
651 static int
652 nfsd(void *vrqstp)
653 {
654         struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
655         struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
656         struct net *net = perm_sock->xpt_net;
657         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
658         int err;
659 
660         /* Lock module and set up kernel thread */
661         mutex_lock(&nfsd_mutex);
662 
663         /* At this point, the thread shares current->fs
664          * with the init process. We need to create files with a
665          * umask of 0 instead of init's umask. */
666         if (unshare_fs_struct() < 0) {
667                 printk("Unable to start nfsd thread: out of memory\n");
668                 goto out;
669         }
670 
671         current->fs->umask = 0;
672 
673         /*
674          * thread is spawned with all signals set to SIG_IGN, re-enable
675          * the ones that will bring down the thread
676          */
677         allow_signal(SIGKILL);
678         allow_signal(SIGHUP);
679         allow_signal(SIGINT);
680         allow_signal(SIGQUIT);
681 
682         nfsdstats.th_cnt++;
683         mutex_unlock(&nfsd_mutex);
684 
685         set_freezable();
686 
687         /*
688          * The main request loop
689          */
690         for (;;) {
691                 /* Update sv_maxconn if it has changed */
692                 rqstp->rq_server->sv_maxconn = nn->max_connections;
693 
694                 /*
695                  * Find a socket with data available and call its
696                  * recvfrom routine.
697                  */
698                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
699                         ;
700                 if (err == -EINTR)
701                         break;
702                 validate_process_creds();
703                 svc_process(rqstp);
704                 validate_process_creds();
705         }
706 
707         /* Clear signals before calling svc_exit_thread() */
708         flush_signals(current);
709 
710         mutex_lock(&nfsd_mutex);
711         nfsdstats.th_cnt --;
712 
713 out:
714         rqstp->rq_server = NULL;
715 
716         /* Release the thread */
717         svc_exit_thread(rqstp);
718 
719         nfsd_destroy(net);
720 
721         /* Release module */
722         mutex_unlock(&nfsd_mutex);
723         module_put_and_exit(0);
724         return 0;
725 }
726 
727 static __be32 map_new_errors(u32 vers, __be32 nfserr)
728 {
729         if (nfserr == nfserr_jukebox && vers == 2)
730                 return nfserr_dropit;
731         if (nfserr == nfserr_wrongsec && vers < 4)
732                 return nfserr_acces;
733         return nfserr;
734 }
735 
736 int
737 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
738 {
739         struct svc_procedure    *proc;
740         kxdrproc_t              xdr;
741         __be32                  nfserr;
742         __be32                  *nfserrp;
743 
744         dprintk("nfsd_dispatch: vers %d proc %d\n",
745                                 rqstp->rq_vers, rqstp->rq_proc);
746         proc = rqstp->rq_procinfo;
747 
748         /*
749          * Give the xdr decoder a chance to change this if it wants
750          * (necessary in the NFSv4.0 compound case)
751          */
752         rqstp->rq_cachetype = proc->pc_cachetype;
753         /* Decode arguments */
754         xdr = proc->pc_decode;
755         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
756                         rqstp->rq_argp)) {
757                 dprintk("nfsd: failed to decode arguments!\n");
758                 *statp = rpc_garbage_args;
759                 return 1;
760         }
761 
762         /* Check whether we have this call in the cache. */
763         switch (nfsd_cache_lookup(rqstp)) {
764         case RC_DROPIT:
765                 return 0;
766         case RC_REPLY:
767                 return 1;
768         case RC_DOIT:;
769                 /* do it */
770         }
771 
772         /* need to grab the location to store the status, as
773          * nfsv4 does some encoding while processing 
774          */
775         nfserrp = rqstp->rq_res.head[0].iov_base
776                 + rqstp->rq_res.head[0].iov_len;
777         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
778 
779         /* Now call the procedure handler, and encode NFS status. */
780         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
781         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
782         if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) {
783                 dprintk("nfsd: Dropping request; may be revisited later\n");
784                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
785                 return 0;
786         }
787 
788         if (rqstp->rq_proc != 0)
789                 *nfserrp++ = nfserr;
790 
791         /* Encode result.
792          * For NFSv2, additional info is never returned in case of an error.
793          */
794         if (!(nfserr && rqstp->rq_vers == 2)) {
795                 xdr = proc->pc_encode;
796                 if (xdr && !xdr(rqstp, nfserrp,
797                                 rqstp->rq_resp)) {
798                         /* Failed to encode result. Release cache entry */
799                         dprintk("nfsd: failed to encode result!\n");
800                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
801                         *statp = rpc_system_err;
802                         return 1;
803                 }
804         }
805 
806         /* Store reply in cache. */
807         nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
808         return 1;
809 }
810 
811 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
812 {
813         int ret;
814         struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
815 
816         mutex_lock(&nfsd_mutex);
817         if (nn->nfsd_serv == NULL) {
818                 mutex_unlock(&nfsd_mutex);
819                 return -ENODEV;
820         }
821         /* bump up the psudo refcount while traversing */
822         svc_get(nn->nfsd_serv);
823         ret = svc_pool_stats_open(nn->nfsd_serv, file);
824         mutex_unlock(&nfsd_mutex);
825         return ret;
826 }
827 
828 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
829 {
830         int ret = seq_release(inode, file);
831         struct net *net = inode->i_sb->s_fs_info;
832 
833         mutex_lock(&nfsd_mutex);
834         /* this function really, really should have been called svc_put() */
835         nfsd_destroy(net);
836         mutex_unlock(&nfsd_mutex);
837         return ret;
838 }
839 

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