aboutsummaryrefslogtreecommitdiffstats
path: root/fs/nfs/nfs4session.c
blob: a5489d70a7244642967422aea12008593536c304 (plain) (blame)
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
/*
 * fs/nfs/nfs4session.c
 *
 * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
 *
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/bc_xprt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/module.h>

#include "nfs4_fs.h"
#include "internal.h"
#include "nfs4session.h"
#include "callback.h"

#define NFSDBG_FACILITY		NFSDBG_STATE

static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
{
	tbl->highest_used_slotid = NFS4_NO_SLOT;
	spin_lock_init(&tbl->slot_tbl_lock);
	rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
	init_waitqueue_head(&tbl->slot_waitq);
	init_completion(&tbl->complete);
}

/*
 * nfs4_shrink_slot_table - free retired slots from the slot table
 */
static void nfs4_shrink_slot_table(struct nfs4_slot_table  *tbl, u32 newsize)
{
	struct nfs4_slot **p;
	if (newsize >= tbl->max_slots)
		return;

	p = &tbl->slots;
	while (newsize--)
		p = &(*p)->next;
	while (*p) {
		struct nfs4_slot *slot = *p;

		*p = slot->next;
		kfree(slot);
		tbl->max_slots--;
	}
}

/**
 * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
 * @tbl - controlling slot table
 *
 */
void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
{
	if (nfs4_slot_tbl_draining(tbl))
		complete(&tbl->complete);
}

/*
 * nfs4_free_slot - free a slot and efficiently update slot table.
 *
 * freeing a slot is trivially done by clearing its respective bit
 * in the bitmap.
 * If the freed slotid equals highest_used_slotid we want to update it
 * so that the server would be able to size down the slot table if needed,
 * otherwise we know that the highest_used_slotid is still in use.
 * When updating highest_used_slotid there may be "holes" in the bitmap
 * so we need to scan down from highest_used_slotid to 0 looking for the now
 * highest slotid in use.
 * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
 *
 * Must be called while holding tbl->slot_tbl_lock
 */
void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
	u32 slotid = slot->slot_nr;

	/* clear used bit in bitmap */
	__clear_bit(slotid, tbl->used_slots);

	/* update highest_used_slotid when it is freed */
	if (slotid == tbl->highest_used_slotid) {
		u32 new_max = find_last_bit(tbl->used_slots, slotid);
		if (new_max < slotid)
			tbl->highest_used_slotid = new_max;
		else {
			tbl->highest_used_slotid = NFS4_NO_SLOT;
			nfs4_slot_tbl_drain_complete(tbl);
		}
	}
	dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
		slotid, tbl->highest_used_slotid);
}

static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table  *tbl,
		u32 slotid, u32 seq_init, gfp_t gfp_mask)
{
	struct nfs4_slot *slot;

	slot = kzalloc(sizeof(*slot), gfp_mask);
	if (slot) {
		slot->table = tbl;
		slot->slot_nr = slotid;
		slot->seq_nr = seq_init;
	}
	return slot;
}

static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table  *tbl,
		u32 slotid, u32 seq_init, gfp_t gfp_mask)
{
	struct nfs4_slot **p, *slot;

	p = &tbl->slots;
	for (;;) {
		if (*p == NULL) {
			*p = nfs4_new_slot(tbl, tbl->max_slots,
					seq_init, gfp_mask);
			if (*p == NULL)
				break;
			tbl->max_slots++;
		}
		slot = *p;
		if (slot->slot_nr == slotid)
			return slot;
		p = &slot->next;
	}
	return ERR_PTR(-ENOMEM);
}

static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot)
{
	u32 slotid = slot->slot_nr;

	__set_bit(slotid, tbl->used_slots);
	if (slotid > tbl->highest_used_slotid ||
	    tbl->highest_used_slotid == NFS4_NO_SLOT)
		tbl->highest_used_slotid = slotid;
	slot->generation = tbl->generation;
}

/*
 * nfs4_try_to_lock_slot - Given a slot try to allocate it
 *
 * Note: must be called with the slot_tbl_lock held.
 */
bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
	if (nfs4_test_locked_slot(tbl, slot->slot_nr))
		return false;
	nfs4_lock_slot(tbl, slot);
	return true;
}

/*
 * nfs4_lookup_slot - Find a slot but don't allocate it
 *
 * Note: must be called with the slot_tbl_lock held.
 */
struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
{
	if (slotid <= tbl->max_slotid)
		return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
	return ERR_PTR(-E2BIG);
}

static int nfs4_slot_get_seqid(struct nfs4_slot_table  *tbl, u32 slotid,
		u32 *seq_nr)
	__must_hold(&tbl->slot_tbl_lock)
{
	struct nfs4_slot *slot;
	int ret;

	slot = nfs4_lookup_slot(tbl, slotid);
	ret = PTR_ERR_OR_ZERO(slot);
	if (!ret)
		*seq_nr = slot->seq_nr;

	return ret;
}

/*
 * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
 *
 * Given a slot table, slot id and sequence number, determine if the
 * RPC call in question is still in flight. This function is mainly
 * intended for use by the callback channel.
 */
static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
		u32 slotid, u32 seq_nr)
{
	u32 cur_seq = 0;
	bool ret = false;

	spin_lock(&tbl->slot_tbl_lock);
	if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
	    cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
		ret = true;
	spin_unlock(&tbl->slot_tbl_lock);
	return ret;
}

/*
 * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
 *
 * Given a slot table, slot id and sequence number, wait until the
 * corresponding RPC call completes. This function is mainly
 * intended for use by the callback channel.
 */
int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
		u32 slotid, u32 seq_nr,
		unsigned long timeout)
{
	if (wait_event_timeout(tbl->slot_waitq,
			!nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
			timeout) == 0)
		return -ETIMEDOUT;
	return 0;
}

/*
 * nfs4_alloc_slot - efficiently look for a free slot
 *
 * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
 * If found, we mark the slot as used, update the highest_used_slotid,
 * and respectively set up the sequence operation args.
 *
 * Note: must be called with under the slot_tbl_lock.
 */
struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
{
	struct nfs4_slot *ret = ERR_PTR(-EBUSY);
	u32 slotid;

	dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
		__func__, tbl->used_slots[0], tbl->highest_used_slotid,
		tbl->max_slotid + 1);
	slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
	if (slotid <= tbl->max_slotid) {
		ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
		if (!IS_ERR(ret))
			nfs4_lock_slot(tbl, ret);
	}
	dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
		__func__, tbl->used_slots[0], tbl->highest_used_slotid,
		!IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
	return ret;
}

static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
		 u32 max_reqs, u32 ivalue)
{
	if (max_reqs <= tbl->max_slots)
		return 0;
	if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
		return 0;
	return -ENOMEM;
}

static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
		u32 server_highest_slotid,
		u32 ivalue)
{
	struct nfs4_slot **p;

	nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
	p = &tbl->slots;
	while (*p) {
		(*p)->seq_nr = ivalue;
		(*p)->interrupted = 0;
		p = &(*p)->next;
	}
	tbl->highest_used_slotid = NFS4_NO_SLOT;
	tbl->target_highest_slotid = server_highest_slotid;
	tbl->server_highest_slotid = server_highest_slotid;
	tbl->d_target_highest_slotid = 0;
	tbl->d2_target_highest_slotid = 0;
	tbl->max_slotid = server_highest_slotid;
}

/*
 * (re)Initialise a slot table
 */
static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
		u32 max_reqs, u32 ivalue)
{
	int ret;

	dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
		max_reqs, tbl->max_slots);

	if (max_reqs > NFS4_MAX_SLOT_TABLE)
		max_reqs = NFS4_MAX_SLOT_TABLE;

	ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
	if (ret)
		goto out;

	spin_lock(&tbl->slot_tbl_lock);
	nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
	spin_unlock(&tbl->slot_tbl_lock);

	dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
		tbl, tbl->slots, tbl->max_slots);
out:
	dprintk("<-- %s: return %d\n", __func__, ret);
	return ret;
}

/*
 * nfs4_release_slot_table - release all slot table entries
 */
static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
{
	nfs4_shrink_slot_table(tbl, 0);
}

/**
 * nfs4_shutdown_slot_table - release resources attached to a slot table
 * @tbl: slot table to shut down
 *
 */
void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
{
	nfs4_release_slot_table(tbl);
	rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
}

/**
 * nfs4_setup_slot_table - prepare a stand-alone slot table for use
 * @tbl: slot table to set up
 * @max_reqs: maximum number of requests allowed
 * @queue: name to give RPC wait queue
 *
 * Returns zero on success, or a negative errno.
 */
int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
		const char *queue)
{
	nfs4_init_slot_table(tbl, queue);
	return nfs4_realloc_slot_table(tbl, max_reqs, 0);
}

static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
{
	struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
	struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
	struct nfs4_slot *slot = pslot;
	struct nfs4_slot_table *tbl = slot->table;

	if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
		return false;
	slot->generation = tbl->generation;
	args->sa_slot = slot;
	res->sr_timestamp = jiffies;
	res->sr_slot = slot;
	res->sr_status_flags = 0;
	res->sr_status = 1;
	return true;
}

static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot)
{
	if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
		return true;
	return false;
}

bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot)
{
	if (slot->slot_nr > tbl->max_slotid)
		return false;
	return __nfs41_wake_and_assign_slot(tbl, slot);
}

static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
{
	struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
	if (!IS_ERR(slot)) {
		bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
		if (ret)
			return ret;
		nfs4_free_slot(tbl, slot);
	}
	return false;
}

void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
{
	for (;;) {
		if (!nfs41_try_wake_next_slot_table_entry(tbl))
			break;
	}
}

#if defined(CONFIG_NFS_V4_1)

static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid)
{
	u32 max_slotid;

	max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
	if (max_slotid > tbl->server_highest_slotid)
		max_slotid = tbl->server_highest_slotid;
	if (max_slotid > tbl->target_highest_slotid)
		max_slotid = tbl->target_highest_slotid;
	tbl->max_slotid = max_slotid;
	nfs41_wake_slot_table(tbl);
}

/* Update the client's idea of target_highest_slotid */
static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid)
{
	if (tbl->target_highest_slotid == target_highest_slotid)
		return;
	tbl->target_highest_slotid = target_highest_slotid;
	tbl->generation++;
}

void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid)
{
	spin_lock(&tbl->slot_tbl_lock);
	nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
	tbl->d_target_highest_slotid = 0;
	tbl->d2_target_highest_slotid = 0;
	nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
	spin_unlock(&tbl->slot_tbl_lock);
}

static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
		u32 highest_slotid)
{
	if (tbl->server_highest_slotid == highest_slotid)
		return;
	if (tbl->highest_used_slotid > highest_slotid)
		return;
	/* Deallocate slots */
	nfs4_shrink_slot_table(tbl, highest_slotid + 1);
	tbl->server_highest_slotid = highest_slotid;
}

static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
{
	s1 -= s2;
	if (s1 == 0)
		return 0;
	if (s1 < 0)
		return (s1 - 1) >> 1;
	return (s1 + 1) >> 1;
}

static int nfs41_sign_s32(s32 s1)
{
	if (s1 > 0)
		return 1;
	if (s1 < 0)
		return -1;
	return 0;
}

static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
{
	if (!s1 || !s2)
		return true;
	return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
}

/* Try to eliminate outliers by checking for sharp changes in the
 * derivatives and second derivatives
 */
static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
		u32 new_target)
{
	s32 d_target, d2_target;
	bool ret = true;

	d_target = nfs41_derivative_target_slotid(new_target,
			tbl->target_highest_slotid);
	d2_target = nfs41_derivative_target_slotid(d_target,
			tbl->d_target_highest_slotid);
	/* Is first derivative same sign? */
	if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
		ret = false;
	/* Is second derivative same sign? */
	if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
		ret = false;
	tbl->d_target_highest_slotid = d_target;
	tbl->d2_target_highest_slotid = d2_target;
	return ret;
}

void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot,
		struct nfs4_sequence_res *res)
{
	spin_lock(&tbl->slot_tbl_lock);
	if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
		nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
	if (tbl->generation == slot->generation)
		nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
	nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
	spin_unlock(&tbl->slot_tbl_lock);
}

static void nfs4_release_session_slot_tables(struct nfs4_session *session)
{
	nfs4_release_slot_table(&session->fc_slot_table);
	nfs4_release_slot_table(&session->bc_slot_table);
}

/*
 * Initialize or reset the forechannel and backchannel tables
 */
int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
{
	struct nfs4_slot_table *tbl;
	int status;

	dprintk("--> %s\n", __func__);
	/* Fore channel */
	tbl = &ses->fc_slot_table;
	tbl->session = ses;
	status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
	if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
		return status;
	/* Back channel */
	tbl = &ses->bc_slot_table;
	tbl->session = ses;
	status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
	if (status && tbl->slots == NULL)
		/* Fore and back channel share a connection so get
		 * both slot tables or neither */
		nfs4_release_session_slot_tables(ses);
	return status;
}

struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
{
	struct nfs4_session *session;

	session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
	if (!session)
		return NULL;

	nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
	nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
	session->session_state = 1<<NFS4_SESSION_INITING;

	session->clp = clp;
	return session;
}

static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
{
	nfs4_shutdown_slot_table(&session->fc_slot_table);
	nfs4_shutdown_slot_table(&session->bc_slot_table);
}

void nfs4_destroy_session(struct nfs4_session *session)
{
	struct rpc_xprt *xprt;
	const struct cred *cred;

	cred = nfs4_get_clid_cred(session->clp);
	nfs4_proc_destroy_session(session, cred);
	put_cred(cred);

	rcu_read_lock();
	xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
	rcu_read_unlock();
	dprintk("%s Destroy backchannel for xprt %p\n",
		__func__, xprt);
	xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
	nfs4_destroy_session_slot_tables(session);
	kfree(session);
}

/*
 * With sessions, the client is not marked ready until after a
 * successful EXCHANGE_ID and CREATE_SESSION.
 *
 * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
 * other versions of NFS can be tried.
 */
static int nfs41_check_session_ready(struct nfs_client *clp)
{
	int ret;
	
	if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
		ret = nfs4_client_recover_expired_lease(clp);
		if (ret)
			return ret;
	}
	if (clp->cl_cons_state < NFS_CS_READY)
		return -EPROTONOSUPPORT;
	smp_rmb();
	return 0;
}

int nfs4_init_session(struct nfs_client *clp)
{
	if (!nfs4_has_session(clp))
		return 0;

	clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
	return nfs41_check_session_ready(clp);
}

int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
{
	struct nfs4_session *session = clp->cl_session;
	int ret;

	spin_lock(&clp->cl_lock);
	if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
		/*
		 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
		 * DS lease to be equal to the MDS lease.
		 */
		clp->cl_lease_time = lease_time;
		clp->cl_last_renewal = jiffies;
	}
	spin_unlock(&clp->cl_lock);

	ret = nfs41_check_session_ready(clp);
	if (ret)
		return ret;
	/* Test for the DS role */
	if (!is_ds_client(clp))
		return -ENODEV;
	return 0;
}
EXPORT_SYMBOL_GPL(nfs4_init_ds_session);

#endif	/* defined(CONFIG_NFS_V4_1) */