xref: /openbmc/linux/fs/nfsd/nfssvc.c (revision 483eb062)
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 		return ret;
225 	ret = nfs4_state_start();
226 	if (ret)
227 		goto out_racache;
228 	return 0;
229 
230 out_racache:
231 	nfsd_racache_shutdown();
232 	return ret;
233 }
234 
235 static void nfsd_shutdown_generic(void)
236 {
237 	if (--nfsd_users)
238 		return;
239 
240 	nfs4_state_shutdown();
241 	nfsd_racache_shutdown();
242 }
243 
244 static bool nfsd_needs_lockd(void)
245 {
246 #if defined(CONFIG_NFSD_V3)
247 	return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
248 #else
249 	return (nfsd_versions[2] != NULL);
250 #endif
251 }
252 
253 static int nfsd_startup_net(int nrservs, struct net *net)
254 {
255 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
256 	int ret;
257 
258 	if (nn->nfsd_net_up)
259 		return 0;
260 
261 	ret = nfsd_startup_generic(nrservs);
262 	if (ret)
263 		return ret;
264 	ret = nfsd_init_socks(net);
265 	if (ret)
266 		goto out_socks;
267 
268 	if (nfsd_needs_lockd() && !nn->lockd_up) {
269 		ret = lockd_up(net);
270 		if (ret)
271 			goto out_socks;
272 		nn->lockd_up = 1;
273 	}
274 
275 	ret = nfs4_state_start_net(net);
276 	if (ret)
277 		goto out_lockd;
278 
279 	nn->nfsd_net_up = true;
280 	return 0;
281 
282 out_lockd:
283 	if (nn->lockd_up) {
284 		lockd_down(net);
285 		nn->lockd_up = 0;
286 	}
287 out_socks:
288 	nfsd_shutdown_generic();
289 	return ret;
290 }
291 
292 static void nfsd_shutdown_net(struct net *net)
293 {
294 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
295 
296 	nfs4_state_shutdown_net(net);
297 	if (nn->lockd_up) {
298 		lockd_down(net);
299 		nn->lockd_up = 0;
300 	}
301 	nn->nfsd_net_up = false;
302 	nfsd_shutdown_generic();
303 }
304 
305 static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
306 {
307 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
308 
309 	/*
310 	 * write_ports can create the server without actually starting
311 	 * any threads--if we get shut down before any threads are
312 	 * started, then nfsd_last_thread will be run before any of this
313 	 * other initialization has been done.
314 	 */
315 	if (!nn->nfsd_net_up)
316 		return;
317 	nfsd_shutdown_net(net);
318 
319 	svc_rpcb_cleanup(serv, net);
320 
321 	printk(KERN_WARNING "nfsd: last server has exited, flushing export "
322 			    "cache\n");
323 	nfsd_export_flush(net);
324 }
325 
326 void nfsd_reset_versions(void)
327 {
328 	int found_one = 0;
329 	int i;
330 
331 	for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
332 		if (nfsd_program.pg_vers[i])
333 			found_one = 1;
334 	}
335 
336 	if (!found_one) {
337 		for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
338 			nfsd_program.pg_vers[i] = nfsd_version[i];
339 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
340 		for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
341 			nfsd_acl_program.pg_vers[i] =
342 				nfsd_acl_version[i];
343 #endif
344 	}
345 }
346 
347 /*
348  * Each session guarantees a negotiated per slot memory cache for replies
349  * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
350  * NFSv4.1 server might want to use more memory for a DRC than a machine
351  * with mutiple services.
352  *
353  * Impose a hard limit on the number of pages for the DRC which varies
354  * according to the machines free pages. This is of course only a default.
355  *
356  * For now this is a #defined shift which could be under admin control
357  * in the future.
358  */
359 static void set_max_drc(void)
360 {
361 	#define NFSD_DRC_SIZE_SHIFT	10
362 	nfsd_drc_max_mem = (nr_free_buffer_pages()
363 					>> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
364 	nfsd_drc_mem_used = 0;
365 	spin_lock_init(&nfsd_drc_lock);
366 	dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
367 }
368 
369 static int nfsd_get_default_max_blksize(void)
370 {
371 	struct sysinfo i;
372 	unsigned long long target;
373 	unsigned long ret;
374 
375 	si_meminfo(&i);
376 	target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
377 	/*
378 	 * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
379 	 * machines, but only uses 32K on 128M machines.  Bottom out at
380 	 * 8K on 32M and smaller.  Of course, this is only a default.
381 	 */
382 	target >>= 12;
383 
384 	ret = NFSSVC_MAXBLKSIZE;
385 	while (ret > target && ret >= 8*1024*2)
386 		ret /= 2;
387 	return ret;
388 }
389 
390 int nfsd_create_serv(struct net *net)
391 {
392 	int error;
393 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
394 
395 	WARN_ON(!mutex_is_locked(&nfsd_mutex));
396 	if (nn->nfsd_serv) {
397 		svc_get(nn->nfsd_serv);
398 		return 0;
399 	}
400 	if (nfsd_max_blksize == 0)
401 		nfsd_max_blksize = nfsd_get_default_max_blksize();
402 	nfsd_reset_versions();
403 	nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
404 				      nfsd_last_thread, nfsd, THIS_MODULE);
405 	if (nn->nfsd_serv == NULL)
406 		return -ENOMEM;
407 
408 	error = svc_bind(nn->nfsd_serv, net);
409 	if (error < 0) {
410 		svc_destroy(nn->nfsd_serv);
411 		return error;
412 	}
413 
414 	set_max_drc();
415 	do_gettimeofday(&nn->nfssvc_boot);		/* record boot time */
416 	return 0;
417 }
418 
419 int nfsd_nrpools(struct net *net)
420 {
421 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
422 
423 	if (nn->nfsd_serv == NULL)
424 		return 0;
425 	else
426 		return nn->nfsd_serv->sv_nrpools;
427 }
428 
429 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
430 {
431 	int i = 0;
432 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
433 
434 	if (nn->nfsd_serv != NULL) {
435 		for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
436 			nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
437 	}
438 
439 	return 0;
440 }
441 
442 void nfsd_destroy(struct net *net)
443 {
444 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
445 	int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
446 
447 	if (destroy)
448 		svc_shutdown_net(nn->nfsd_serv, net);
449 	svc_destroy(nn->nfsd_serv);
450 	if (destroy)
451 		nn->nfsd_serv = NULL;
452 }
453 
454 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
455 {
456 	int i = 0;
457 	int tot = 0;
458 	int err = 0;
459 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
460 
461 	WARN_ON(!mutex_is_locked(&nfsd_mutex));
462 
463 	if (nn->nfsd_serv == NULL || n <= 0)
464 		return 0;
465 
466 	if (n > nn->nfsd_serv->sv_nrpools)
467 		n = nn->nfsd_serv->sv_nrpools;
468 
469 	/* enforce a global maximum number of threads */
470 	tot = 0;
471 	for (i = 0; i < n; i++) {
472 		if (nthreads[i] > NFSD_MAXSERVS)
473 			nthreads[i] = NFSD_MAXSERVS;
474 		tot += nthreads[i];
475 	}
476 	if (tot > NFSD_MAXSERVS) {
477 		/* total too large: scale down requested numbers */
478 		for (i = 0; i < n && tot > 0; i++) {
479 		    	int new = nthreads[i] * NFSD_MAXSERVS / tot;
480 			tot -= (nthreads[i] - new);
481 			nthreads[i] = new;
482 		}
483 		for (i = 0; i < n && tot > 0; i++) {
484 			nthreads[i]--;
485 			tot--;
486 		}
487 	}
488 
489 	/*
490 	 * There must always be a thread in pool 0; the admin
491 	 * can't shut down NFS completely using pool_threads.
492 	 */
493 	if (nthreads[0] == 0)
494 		nthreads[0] = 1;
495 
496 	/* apply the new numbers */
497 	svc_get(nn->nfsd_serv);
498 	for (i = 0; i < n; i++) {
499 		err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
500 				    	  nthreads[i]);
501 		if (err)
502 			break;
503 	}
504 	nfsd_destroy(net);
505 	return err;
506 }
507 
508 /*
509  * Adjust the number of threads and return the new number of threads.
510  * This is also the function that starts the server if necessary, if
511  * this is the first time nrservs is nonzero.
512  */
513 int
514 nfsd_svc(int nrservs, struct net *net)
515 {
516 	int	error;
517 	bool	nfsd_up_before;
518 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
519 
520 	mutex_lock(&nfsd_mutex);
521 	dprintk("nfsd: creating service\n");
522 	if (nrservs <= 0)
523 		nrservs = 0;
524 	if (nrservs > NFSD_MAXSERVS)
525 		nrservs = NFSD_MAXSERVS;
526 	error = 0;
527 	if (nrservs == 0 && nn->nfsd_serv == NULL)
528 		goto out;
529 
530 	error = nfsd_create_serv(net);
531 	if (error)
532 		goto out;
533 
534 	nfsd_up_before = nn->nfsd_net_up;
535 
536 	error = nfsd_startup_net(nrservs, net);
537 	if (error)
538 		goto out_destroy;
539 	error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
540 	if (error)
541 		goto out_shutdown;
542 	/* We are holding a reference to nn->nfsd_serv which
543 	 * we don't want to count in the return value,
544 	 * so subtract 1
545 	 */
546 	error = nn->nfsd_serv->sv_nrthreads - 1;
547 out_shutdown:
548 	if (error < 0 && !nfsd_up_before)
549 		nfsd_shutdown_net(net);
550 out_destroy:
551 	nfsd_destroy(net);		/* Release server */
552 out:
553 	mutex_unlock(&nfsd_mutex);
554 	return error;
555 }
556 
557 
558 /*
559  * This is the NFS server kernel thread
560  */
561 static int
562 nfsd(void *vrqstp)
563 {
564 	struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
565 	struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
566 	struct net *net = perm_sock->xpt_net;
567 	int err;
568 
569 	/* Lock module and set up kernel thread */
570 	mutex_lock(&nfsd_mutex);
571 
572 	/* At this point, the thread shares current->fs
573 	 * with the init process. We need to create files with a
574 	 * umask of 0 instead of init's umask. */
575 	if (unshare_fs_struct() < 0) {
576 		printk("Unable to start nfsd thread: out of memory\n");
577 		goto out;
578 	}
579 
580 	current->fs->umask = 0;
581 
582 	/*
583 	 * thread is spawned with all signals set to SIG_IGN, re-enable
584 	 * the ones that will bring down the thread
585 	 */
586 	allow_signal(SIGKILL);
587 	allow_signal(SIGHUP);
588 	allow_signal(SIGINT);
589 	allow_signal(SIGQUIT);
590 
591 	nfsdstats.th_cnt++;
592 	mutex_unlock(&nfsd_mutex);
593 
594 	/*
595 	 * We want less throttling in balance_dirty_pages() so that nfs to
596 	 * localhost doesn't cause nfsd to lock up due to all the client's
597 	 * dirty pages.
598 	 */
599 	current->flags |= PF_LESS_THROTTLE;
600 	set_freezable();
601 
602 	/*
603 	 * The main request loop
604 	 */
605 	for (;;) {
606 		/*
607 		 * Find a socket with data available and call its
608 		 * recvfrom routine.
609 		 */
610 		while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
611 			;
612 		if (err == -EINTR)
613 			break;
614 		validate_process_creds();
615 		svc_process(rqstp);
616 		validate_process_creds();
617 	}
618 
619 	/* Clear signals before calling svc_exit_thread() */
620 	flush_signals(current);
621 
622 	mutex_lock(&nfsd_mutex);
623 	nfsdstats.th_cnt --;
624 
625 out:
626 	rqstp->rq_server = NULL;
627 
628 	/* Release the thread */
629 	svc_exit_thread(rqstp);
630 
631 	nfsd_destroy(net);
632 
633 	/* Release module */
634 	mutex_unlock(&nfsd_mutex);
635 	module_put_and_exit(0);
636 	return 0;
637 }
638 
639 static __be32 map_new_errors(u32 vers, __be32 nfserr)
640 {
641 	if (nfserr == nfserr_jukebox && vers == 2)
642 		return nfserr_dropit;
643 	if (nfserr == nfserr_wrongsec && vers < 4)
644 		return nfserr_acces;
645 	return nfserr;
646 }
647 
648 int
649 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
650 {
651 	struct svc_procedure	*proc;
652 	kxdrproc_t		xdr;
653 	__be32			nfserr;
654 	__be32			*nfserrp;
655 
656 	dprintk("nfsd_dispatch: vers %d proc %d\n",
657 				rqstp->rq_vers, rqstp->rq_proc);
658 	proc = rqstp->rq_procinfo;
659 
660 	/*
661 	 * Give the xdr decoder a chance to change this if it wants
662 	 * (necessary in the NFSv4.0 compound case)
663 	 */
664 	rqstp->rq_cachetype = proc->pc_cachetype;
665 	/* Decode arguments */
666 	xdr = proc->pc_decode;
667 	if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
668 			rqstp->rq_argp)) {
669 		dprintk("nfsd: failed to decode arguments!\n");
670 		*statp = rpc_garbage_args;
671 		return 1;
672 	}
673 
674 	/* Check whether we have this call in the cache. */
675 	switch (nfsd_cache_lookup(rqstp)) {
676 	case RC_DROPIT:
677 		return 0;
678 	case RC_REPLY:
679 		return 1;
680 	case RC_DOIT:;
681 		/* do it */
682 	}
683 
684 	/* need to grab the location to store the status, as
685 	 * nfsv4 does some encoding while processing
686 	 */
687 	nfserrp = rqstp->rq_res.head[0].iov_base
688 		+ rqstp->rq_res.head[0].iov_len;
689 	rqstp->rq_res.head[0].iov_len += sizeof(__be32);
690 
691 	/* Now call the procedure handler, and encode NFS status. */
692 	nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
693 	nfserr = map_new_errors(rqstp->rq_vers, nfserr);
694 	if (nfserr == nfserr_dropit || rqstp->rq_dropme) {
695 		dprintk("nfsd: Dropping request; may be revisited later\n");
696 		nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
697 		return 0;
698 	}
699 
700 	if (rqstp->rq_proc != 0)
701 		*nfserrp++ = nfserr;
702 
703 	/* Encode result.
704 	 * For NFSv2, additional info is never returned in case of an error.
705 	 */
706 	if (!(nfserr && rqstp->rq_vers == 2)) {
707 		xdr = proc->pc_encode;
708 		if (xdr && !xdr(rqstp, nfserrp,
709 				rqstp->rq_resp)) {
710 			/* Failed to encode result. Release cache entry */
711 			dprintk("nfsd: failed to encode result!\n");
712 			nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
713 			*statp = rpc_system_err;
714 			return 1;
715 		}
716 	}
717 
718 	/* Store reply in cache. */
719 	nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
720 	return 1;
721 }
722 
723 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
724 {
725 	int ret;
726 	struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
727 
728 	mutex_lock(&nfsd_mutex);
729 	if (nn->nfsd_serv == NULL) {
730 		mutex_unlock(&nfsd_mutex);
731 		return -ENODEV;
732 	}
733 	/* bump up the psudo refcount while traversing */
734 	svc_get(nn->nfsd_serv);
735 	ret = svc_pool_stats_open(nn->nfsd_serv, file);
736 	mutex_unlock(&nfsd_mutex);
737 	return ret;
738 }
739 
740 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
741 {
742 	int ret = seq_release(inode, file);
743 	struct net *net = inode->i_sb->s_fs_info;
744 
745 	mutex_lock(&nfsd_mutex);
746 	/* this function really, really should have been called svc_put() */
747 	nfsd_destroy(net);
748 	mutex_unlock(&nfsd_mutex);
749 	return ret;
750 }
751