Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
/*
 * Central processing for nfsd.
 *
 * Authors:	Olaf Kirch (okir@monad.swb.de)
 *
 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/sched.h>
#include <linux/freezer.h>
#include <linux/module.h>
#include <linux/fs_struct.h>
#include <linux/swap.h>

#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/lockd/bind.h>
#include <linux/nfsacl.h>
#include <linux/seq_file.h>
#include <net/net_namespace.h>
#include "nfsd.h"
#include "cache.h"
#include "vfs.h"
#include "netns.h"

#define NFSDDBG_FACILITY	NFSDDBG_SVC

extern struct svc_program	nfsd_program;
static int			nfsd(void *vrqstp);

/*
 * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members
 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
 *
 * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a
 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
 * of nfsd threads must exist and each must listed in ->sp_all_threads in each
 * entry of ->sv_pools[].
 *
 * Transitions of the thread count between zero and non-zero are of particular
 * interest since the svc_serv needs to be created and initialized at that
 * point, or freed.
 *
 * Finally, the nfsd_mutex also protects some of the global variables that are
 * accessed when nfsd starts and that are settable via the write_* routines in
 * nfsctl.c. In particular:
 *
 *	user_recovery_dirname
 *	user_lease_time
 *	nfsd_versions
 */
DEFINE_MUTEX(nfsd_mutex);

/*
 * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
 * nfsd_drc_max_pages limits the total amount of memory available for
 * version 4.1 DRC caches.
 * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
 */
spinlock_t	nfsd_drc_lock;
unsigned long	nfsd_drc_max_mem;
unsigned long	nfsd_drc_mem_used;

#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
static struct svc_stat	nfsd_acl_svcstats;
static struct svc_version *	nfsd_acl_version[] = {
	[2] = &nfsd_acl_version2,
	[3] = &nfsd_acl_version3,
};

#define NFSD_ACL_MINVERS            2
#define NFSD_ACL_NRVERS		ARRAY_SIZE(nfsd_acl_version)
static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];

static struct svc_program	nfsd_acl_program = {
	.pg_prog		= NFS_ACL_PROGRAM,
	.pg_nvers		= NFSD_ACL_NRVERS,
	.pg_vers		= nfsd_acl_versions,
	.pg_name		= "nfsacl",
	.pg_class		= "nfsd",
	.pg_stats		= &nfsd_acl_svcstats,
	.pg_authenticate	= &svc_set_client,
};

static struct svc_stat	nfsd_acl_svcstats = {
	.program	= &nfsd_acl_program,
};
#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */

static struct svc_version *	nfsd_version[] = {
	[2] = &nfsd_version2,
#if defined(CONFIG_NFSD_V3)
	[3] = &nfsd_version3,
#endif
#if defined(CONFIG_NFSD_V4)
	[4] = &nfsd_version4,
#endif
};

#define NFSD_MINVERS    	2
#define NFSD_NRVERS		ARRAY_SIZE(nfsd_version)
static struct svc_version *nfsd_versions[NFSD_NRVERS];

struct svc_program		nfsd_program = {
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
	.pg_next		= &nfsd_acl_program,
#endif
	.pg_prog		= NFS_PROGRAM,		/* program number */
	.pg_nvers		= NFSD_NRVERS,		/* nr of entries in nfsd_version */
	.pg_vers		= nfsd_versions,	/* version table */
	.pg_name		= "nfsd",		/* program name */
	.pg_class		= "nfsd",		/* authentication class */
	.pg_stats		= &nfsd_svcstats,	/* version table */
	.pg_authenticate	= &svc_set_client,	/* export authentication */

};

static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = {
	[0] = 1,
	[1] = 1,
	[2] = 1,
};

int nfsd_vers(int vers, enum vers_op change)
{
	if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
		return 0;
	switch(change) {
	case NFSD_SET:
		nfsd_versions[vers] = nfsd_version[vers];
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
		if (vers < NFSD_ACL_NRVERS)
			nfsd_acl_versions[vers] = nfsd_acl_version[vers];
#endif
		break;
	case NFSD_CLEAR:
		nfsd_versions[vers] = NULL;
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
		if (vers < NFSD_ACL_NRVERS)
			nfsd_acl_versions[vers] = NULL;
#endif
		break;
	case NFSD_TEST:
		return nfsd_versions[vers] != NULL;
	case NFSD_AVAIL:
		return nfsd_version[vers] != NULL;
	}
	return 0;
}

int nfsd_minorversion(u32 minorversion, enum vers_op change)
{
	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
	    change != NFSD_AVAIL)
		return -1;
	switch(change) {
	case NFSD_SET:
		nfsd_supported_minorversions[minorversion] = true;
		break;
	case NFSD_CLEAR:
		nfsd_supported_minorversions[minorversion] = false;
		break;
	case NFSD_TEST:
		return nfsd_supported_minorversions[minorversion];
	case NFSD_AVAIL:
		return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
	}
	return 0;
}

/*
 * Maximum number of nfsd processes
 */
#define	NFSD_MAXSERVS		8192

int nfsd_nrthreads(struct net *net)
{
	int rv = 0;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	mutex_lock(&nfsd_mutex);
	if (nn->nfsd_serv)
		rv = nn->nfsd_serv->sv_nrthreads;
	mutex_unlock(&nfsd_mutex);
	return rv;
}

static int nfsd_init_socks(struct net *net)
{
	int error;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	if (!list_empty(&nn->nfsd_serv->sv_permsocks))
		return 0;

	error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
					SVC_SOCK_DEFAULTS);
	if (error < 0)
		return error;

	error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
					SVC_SOCK_DEFAULTS);
	if (error < 0)
		return error;

	return 0;
}

static int nfsd_users = 0;

static int nfsd_startup_generic(int nrservs)
{
	int ret;

	if (nfsd_users++)
		return 0;

	/*
	 * Readahead param cache - will no-op if it already exists.
	 * (Note therefore results will be suboptimal if number of
	 * threads is modified after nfsd start.)
	 */
	ret = nfsd_racache_init(2*nrservs);
	if (ret)
		goto dec_users;

	ret = nfs4_state_start();
	if (ret)
		goto out_racache;
	return 0;

out_racache:
	nfsd_racache_shutdown();
dec_users:
	nfsd_users--;
	return ret;
}

static void nfsd_shutdown_generic(void)
{
	if (--nfsd_users)
		return;

	nfs4_state_shutdown();
	nfsd_racache_shutdown();
}

static bool nfsd_needs_lockd(void)
{
#if defined(CONFIG_NFSD_V3)
	return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
#else
	return (nfsd_versions[2] != NULL);
#endif
}

static int nfsd_startup_net(int nrservs, struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	int ret;

	if (nn->nfsd_net_up)
		return 0;

	ret = nfsd_startup_generic(nrservs);
	if (ret)
		return ret;
	ret = nfsd_init_socks(net);
	if (ret)
		goto out_socks;

	if (nfsd_needs_lockd() && !nn->lockd_up) {
		ret = lockd_up(net);
		if (ret)
			goto out_socks;
		nn->lockd_up = 1;
	}

	ret = nfs4_state_start_net(net);
	if (ret)
		goto out_lockd;

	nn->nfsd_net_up = true;
	return 0;

out_lockd:
	if (nn->lockd_up) {
		lockd_down(net);
		nn->lockd_up = 0;
	}
out_socks:
	nfsd_shutdown_generic();
	return ret;
}

static void nfsd_shutdown_net(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	nfs4_state_shutdown_net(net);
	if (nn->lockd_up) {
		lockd_down(net);
		nn->lockd_up = 0;
	}
	nn->nfsd_net_up = false;
	nfsd_shutdown_generic();
}

static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	/*
	 * write_ports can create the server without actually starting
	 * any threads--if we get shut down before any threads are
	 * started, then nfsd_last_thread will be run before any of this
	 * other initialization has been done.
	 */
	if (!nn->nfsd_net_up)
		return;
	nfsd_shutdown_net(net);

	svc_rpcb_cleanup(serv, net);

	printk(KERN_WARNING "nfsd: last server has exited, flushing export "
			    "cache\n");
	nfsd_export_flush(net);
}

void nfsd_reset_versions(void)
{
	int i;

	for (i = 0; i < NFSD_NRVERS; i++)
		if (nfsd_vers(i, NFSD_TEST))
			return;

	for (i = 0; i < NFSD_NRVERS; i++)
		if (i != 4)
			nfsd_vers(i, NFSD_SET);
		else {
			int minor = 0;
			while (nfsd_minorversion(minor, NFSD_SET) >= 0)
				minor++;
		}
}

/*
 * Each session guarantees a negotiated per slot memory cache for replies
 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 * NFSv4.1 server might want to use more memory for a DRC than a machine
 * with mutiple services.
 *
 * Impose a hard limit on the number of pages for the DRC which varies
 * according to the machines free pages. This is of course only a default.
 *
 * For now this is a #defined shift which could be under admin control
 * in the future.
 */
static void set_max_drc(void)
{
	#define NFSD_DRC_SIZE_SHIFT	10
	nfsd_drc_max_mem = (nr_free_buffer_pages()
					>> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
	nfsd_drc_mem_used = 0;
	spin_lock_init(&nfsd_drc_lock);
	dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
}

static int nfsd_get_default_max_blksize(void)
{
	struct sysinfo i;
	unsigned long long target;
	unsigned long ret;

	si_meminfo(&i);
	target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
	/*
	 * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
	 * machines, but only uses 32K on 128M machines.  Bottom out at
	 * 8K on 32M and smaller.  Of course, this is only a default.
	 */
	target >>= 12;

	ret = NFSSVC_MAXBLKSIZE;
	while (ret > target && ret >= 8*1024*2)
		ret /= 2;
	return ret;
}

static struct svc_serv_ops nfsd_thread_sv_ops = {
	.svo_shutdown		= nfsd_last_thread,
	.svo_function		= nfsd,
	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
	.svo_setup		= svc_set_num_threads,
	.svo_module		= THIS_MODULE,
};

int nfsd_create_serv(struct net *net)
{
	int error;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	WARN_ON(!mutex_is_locked(&nfsd_mutex));
	if (nn->nfsd_serv) {
		svc_get(nn->nfsd_serv);
		return 0;
	}
	if (nfsd_max_blksize == 0)
		nfsd_max_blksize = nfsd_get_default_max_blksize();
	nfsd_reset_versions();
	nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
						&nfsd_thread_sv_ops);
	if (nn->nfsd_serv == NULL)
		return -ENOMEM;

	nn->nfsd_serv->sv_maxconn = nn->max_connections;
	error = svc_bind(nn->nfsd_serv, net);
	if (error < 0) {
		svc_destroy(nn->nfsd_serv);
		return error;
	}

	set_max_drc();
	do_gettimeofday(&nn->nfssvc_boot);		/* record boot time */
	return 0;
}

int nfsd_nrpools(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	if (nn->nfsd_serv == NULL)
		return 0;
	else
		return nn->nfsd_serv->sv_nrpools;
}

int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
{
	int i = 0;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	if (nn->nfsd_serv != NULL) {
		for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
			nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
	}

	return 0;
}

void nfsd_destroy(struct net *net)
{
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	int destroy = (nn->nfsd_serv->sv_nrthreads == 1);

	if (destroy)
		svc_shutdown_net(nn->nfsd_serv, net);
	svc_destroy(nn->nfsd_serv);
	if (destroy)
		nn->nfsd_serv = NULL;
}

int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
{
	int i = 0;
	int tot = 0;
	int err = 0;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	WARN_ON(!mutex_is_locked(&nfsd_mutex));

	if (nn->nfsd_serv == NULL || n <= 0)
		return 0;

	if (n > nn->nfsd_serv->sv_nrpools)
		n = nn->nfsd_serv->sv_nrpools;

	/* enforce a global maximum number of threads */
	tot = 0;
	for (i = 0; i < n; i++) {
		nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
		tot += nthreads[i];
	}
	if (tot > NFSD_MAXSERVS) {
		/* total too large: scale down requested numbers */
		for (i = 0; i < n && tot > 0; i++) {
		    	int new = nthreads[i] * NFSD_MAXSERVS / tot;
			tot -= (nthreads[i] - new);
			nthreads[i] = new;
		}
		for (i = 0; i < n && tot > 0; i++) {
			nthreads[i]--;
			tot--;
		}
	}

	/*
	 * There must always be a thread in pool 0; the admin
	 * can't shut down NFS completely using pool_threads.
	 */
	if (nthreads[0] == 0)
		nthreads[0] = 1;

	/* apply the new numbers */
	svc_get(nn->nfsd_serv);
	for (i = 0; i < n; i++) {
		err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
				&nn->nfsd_serv->sv_pools[i], nthreads[i]);
		if (err)
			break;
	}
	nfsd_destroy(net);
	return err;
}

/*
 * Adjust the number of threads and return the new number of threads.
 * This is also the function that starts the server if necessary, if
 * this is the first time nrservs is nonzero.
 */
int
nfsd_svc(int nrservs, struct net *net)
{
	int	error;
	bool	nfsd_up_before;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	mutex_lock(&nfsd_mutex);
	dprintk("nfsd: creating service\n");

	nrservs = max(nrservs, 0);
	nrservs = min(nrservs, NFSD_MAXSERVS);
	error = 0;

	if (nrservs == 0 && nn->nfsd_serv == NULL)
		goto out;

	error = nfsd_create_serv(net);
	if (error)
		goto out;

	nfsd_up_before = nn->nfsd_net_up;

	error = nfsd_startup_net(nrservs, net);
	if (error)
		goto out_destroy;
	error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
			NULL, nrservs);
	if (error)
		goto out_shutdown;
	/* We are holding a reference to nn->nfsd_serv which
	 * we don't want to count in the return value,
	 * so subtract 1
	 */
	error = nn->nfsd_serv->sv_nrthreads - 1;
out_shutdown:
	if (error < 0 && !nfsd_up_before)
		nfsd_shutdown_net(net);
out_destroy:
	nfsd_destroy(net);		/* Release server */
out:
	mutex_unlock(&nfsd_mutex);
	return error;
}


/*
 * This is the NFS server kernel thread
 */
static int
nfsd(void *vrqstp)
{
	struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
	struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
	struct net *net = perm_sock->xpt_net;
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
	int err;

	/* Lock module and set up kernel thread */
	mutex_lock(&nfsd_mutex);

	/* At this point, the thread shares current->fs
	 * with the init process. We need to create files with a
	 * umask of 0 instead of init's umask. */
	if (unshare_fs_struct() < 0) {
		printk("Unable to start nfsd thread: out of memory\n");
		goto out;
	}

	current->fs->umask = 0;

	/*
	 * thread is spawned with all signals set to SIG_IGN, re-enable
	 * the ones that will bring down the thread
	 */
	allow_signal(SIGKILL);
	allow_signal(SIGHUP);
	allow_signal(SIGINT);
	allow_signal(SIGQUIT);

	nfsdstats.th_cnt++;
	mutex_unlock(&nfsd_mutex);

	set_freezable();

	/*
	 * The main request loop
	 */
	for (;;) {
		/* Update sv_maxconn if it has changed */
		rqstp->rq_server->sv_maxconn = nn->max_connections;

		/*
		 * Find a socket with data available and call its
		 * recvfrom routine.
		 */
		while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
			;
		if (err == -EINTR)
			break;
		validate_process_creds();
		svc_process(rqstp);
		validate_process_creds();
	}

	/* Clear signals before calling svc_exit_thread() */
	flush_signals(current);

	mutex_lock(&nfsd_mutex);
	nfsdstats.th_cnt --;

out:
	rqstp->rq_server = NULL;

	/* Release the thread */
	svc_exit_thread(rqstp);

	nfsd_destroy(net);

	/* Release module */
	mutex_unlock(&nfsd_mutex);
	module_put_and_exit(0);
	return 0;
}

static __be32 map_new_errors(u32 vers, __be32 nfserr)
{
	if (nfserr == nfserr_jukebox && vers == 2)
		return nfserr_dropit;
	if (nfserr == nfserr_wrongsec && vers < 4)
		return nfserr_acces;
	return nfserr;
}

/*
 * A write procedure can have a large argument, and a read procedure can
 * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
 * reply that can both be larger than a page.  The xdr code has taken
 * advantage of this assumption to be a sloppy about bounds checking in
 * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
 * problem, we enforce these assumptions here:
 */
static bool nfs_request_too_big(struct svc_rqst *rqstp,
				struct svc_procedure *proc)
{
	/*
	 * The ACL code has more careful bounds-checking and is not
	 * susceptible to this problem:
	 */
	if (rqstp->rq_prog != NFS_PROGRAM)
		return false;
	/*
	 * Ditto NFSv4 (which can in theory have argument and reply both
	 * more than a page):
	 */
	if (rqstp->rq_vers >= 4)
		return false;
	/* The reply will be small, we're OK: */
	if (proc->pc_xdrressize > 0 &&
	    proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
		return false;

	return rqstp->rq_arg.len > PAGE_SIZE;
}

int
nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
{
	struct svc_procedure	*proc;
	kxdrproc_t		xdr;
	__be32			nfserr;
	__be32			*nfserrp;

	dprintk("nfsd_dispatch: vers %d proc %d\n",
				rqstp->rq_vers, rqstp->rq_proc);
	proc = rqstp->rq_procinfo;

	if (nfs_request_too_big(rqstp, proc)) {
		dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
		*statp = rpc_garbage_args;
		return 1;
	}
	/*
	 * Give the xdr decoder a chance to change this if it wants
	 * (necessary in the NFSv4.0 compound case)
	 */
	rqstp->rq_cachetype = proc->pc_cachetype;
	/* Decode arguments */
	xdr = proc->pc_decode;
	if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
			rqstp->rq_argp)) {
		dprintk("nfsd: failed to decode arguments!\n");
		*statp = rpc_garbage_args;
		return 1;
	}

	/* Check whether we have this call in the cache. */
	switch (nfsd_cache_lookup(rqstp)) {
	case RC_DROPIT:
		return 0;
	case RC_REPLY:
		return 1;
	case RC_DOIT:;
		/* do it */
	}

	/* need to grab the location to store the status, as
	 * nfsv4 does some encoding while processing 
	 */
	nfserrp = rqstp->rq_res.head[0].iov_base
		+ rqstp->rq_res.head[0].iov_len;
	rqstp->rq_res.head[0].iov_len += sizeof(__be32);

	/* Now call the procedure handler, and encode NFS status. */
	nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
	nfserr = map_new_errors(rqstp->rq_vers, nfserr);
	if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) {
		dprintk("nfsd: Dropping request; may be revisited later\n");
		nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
		return 0;
	}

	if (rqstp->rq_proc != 0)
		*nfserrp++ = nfserr;

	/* Encode result.
	 * For NFSv2, additional info is never returned in case of an error.
	 */
	if (!(nfserr && rqstp->rq_vers == 2)) {
		xdr = proc->pc_encode;
		if (xdr && !xdr(rqstp, nfserrp,
				rqstp->rq_resp)) {
			/* Failed to encode result. Release cache entry */
			dprintk("nfsd: failed to encode result!\n");
			nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
			*statp = rpc_system_err;
			return 1;
		}
	}

	/* Store reply in cache. */
	nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
	return 1;
}

int nfsd_pool_stats_open(struct inode *inode, struct file *file)
{
	int ret;
	struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);

	mutex_lock(&nfsd_mutex);
	if (nn->nfsd_serv == NULL) {
		mutex_unlock(&nfsd_mutex);
		return -ENODEV;
	}
	/* bump up the psudo refcount while traversing */
	svc_get(nn->nfsd_serv);
	ret = svc_pool_stats_open(nn->nfsd_serv, file);
	mutex_unlock(&nfsd_mutex);
	return ret;
}

int nfsd_pool_stats_release(struct inode *inode, struct file *file)
{
	int ret = seq_release(inode, file);
	struct net *net = inode->i_sb->s_fs_info;

	mutex_lock(&nfsd_mutex);
	/* this function really, really should have been called svc_put() */
	nfsd_destroy(net);
	mutex_unlock(&nfsd_mutex);
	return ret;
}