xref: /openbmc/linux/fs/nfsd/nfssvc.c (revision 609e478b)
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 }
752