aboutsummaryrefslogtreecommitdiff
path: root/fs/nfs/nfs4client.c
blob: 2e9779b58b7af6f3d143e60af3fba6abc8902a11 (plain)
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
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
/*
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */
#include <linux/module.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs_mount.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/xprt.h>
#include <linux/sunrpc/bc_xprt.h>
#include "internal.h"
#include "callback.h"
#include "delegation.h"
#include "nfs4session.h"
#include "pnfs.h"
#include "netns.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

/*
 * Get a unique NFSv4.0 callback identifier which will be used
 * by the V4.0 callback service to lookup the nfs_client struct
 */
static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
{
	int ret = 0;
	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);

	if (clp->rpc_ops->version != 4 || minorversion != 0)
		return ret;
retry:
	if (!idr_pre_get(&nn->cb_ident_idr, GFP_KERNEL))
		return -ENOMEM;
	spin_lock(&nn->nfs_client_lock);
	ret = idr_get_new(&nn->cb_ident_idr, clp, &clp->cl_cb_ident);
	spin_unlock(&nn->nfs_client_lock);
	if (ret == -EAGAIN)
		goto retry;
	return ret;
}

#ifdef CONFIG_NFS_V4_1
static void nfs4_shutdown_session(struct nfs_client *clp)
{
	if (nfs4_has_session(clp)) {
		nfs4_destroy_session(clp->cl_session);
		nfs4_destroy_clientid(clp);
	}

}
#else /* CONFIG_NFS_V4_1 */
static void nfs4_shutdown_session(struct nfs_client *clp)
{
}
#endif /* CONFIG_NFS_V4_1 */

struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
{
	int err;
	struct nfs_client *clp = nfs_alloc_client(cl_init);
	if (IS_ERR(clp))
		return clp;

	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
	if (err)
		goto error;

	spin_lock_init(&clp->cl_lock);
	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
	clp->cl_minorversion = cl_init->minorversion;
	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
	return clp;

error:
	nfs_free_client(clp);
	return ERR_PTR(err);
}

/*
 * Destroy the NFS4 callback service
 */
static void nfs4_destroy_callback(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
}

static void nfs4_shutdown_client(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
		nfs4_kill_renewd(clp);
	nfs4_shutdown_session(clp);
	nfs4_destroy_callback(clp);
	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
		nfs_idmap_delete(clp);

	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
	kfree(clp->cl_serverowner);
	kfree(clp->cl_serverscope);
	kfree(clp->cl_implid);
}

void nfs4_free_client(struct nfs_client *clp)
{
	nfs4_shutdown_client(clp);
	nfs_free_client(clp);
}

/*
 * Initialize the NFS4 callback service
 */
static int nfs4_init_callback(struct nfs_client *clp)
{
	int error;

	if (clp->rpc_ops->version == 4) {
		struct rpc_xprt *xprt;

		xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);

		if (nfs4_has_session(clp)) {
			error = xprt_setup_backchannel(xprt,
						NFS41_BC_MIN_CALLBACKS);
			if (error < 0)
				return error;
		}

		error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
		if (error < 0) {
			dprintk("%s: failed to start callback. Error = %d\n",
				__func__, error);
			return error;
		}
		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
	}
	return 0;
}

/*
 * Initialize the minor version specific parts of an NFS4 client record
 */
static int nfs4_init_client_minor_version(struct nfs_client *clp)
{
#if defined(CONFIG_NFS_V4_1)
	if (clp->cl_mvops->minor_version) {
		struct nfs4_session *session = NULL;
		/*
		 * Create the session and mark it expired.
		 * When a SEQUENCE operation encounters the expired session
		 * it will do session recovery to initialize it.
		 */
		session = nfs4_alloc_session(clp);
		if (!session)
			return -ENOMEM;

		clp->cl_session = session;
		/*
		 * The create session reply races with the server back
		 * channel probe. Mark the client NFS_CS_SESSION_INITING
		 * so that the client back channel can find the
		 * nfs_client struct
		 */
		nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
	}
#endif /* CONFIG_NFS_V4_1 */

	return nfs4_init_callback(clp);
}

/**
 * nfs4_init_client - Initialise an NFS4 client record
 *
 * @clp: nfs_client to initialise
 * @timeparms: timeout parameters for underlying RPC transport
 * @ip_addr: callback IP address in presentation format
 * @authflavor: authentication flavor for underlying RPC transport
 *
 * Returns pointer to an NFS client, or an ERR_PTR value.
 */
struct nfs_client *nfs4_init_client(struct nfs_client *clp,
				    const struct rpc_timeout *timeparms,
				    const char *ip_addr,
				    rpc_authflavor_t authflavour)
{
	char buf[INET6_ADDRSTRLEN + 1];
	struct nfs_client *old;
	int error;

	if (clp->cl_cons_state == NFS_CS_READY) {
		/* the client is initialised already */
		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
		return clp;
	}

	/* Check NFS protocol revision and initialize RPC op vector */
	clp->rpc_ops = &nfs_v4_clientops;

	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
	error = nfs_create_rpc_client(clp, timeparms, authflavour);
	if (error < 0)
		goto error;

	/* If no clientaddr= option was specified, find a usable cb address */
	if (ip_addr == NULL) {
		struct sockaddr_storage cb_addr;
		struct sockaddr *sap = (struct sockaddr *)&cb_addr;

		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
		if (error < 0)
			goto error;
		error = rpc_ntop(sap, buf, sizeof(buf));
		if (error < 0)
			goto error;
		ip_addr = (const char *)buf;
	}
	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));

	error = nfs_idmap_new(clp);
	if (error < 0) {
		dprintk("%s: failed to create idmapper. Error = %d\n",
			__func__, error);
		goto error;
	}
	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);

	error = nfs4_init_client_minor_version(clp);
	if (error < 0)
		goto error;

	if (!nfs4_has_session(clp))
		nfs_mark_client_ready(clp, NFS_CS_READY);

	error = nfs4_discover_server_trunking(clp, &old);
	if (error < 0)
		goto error;
	nfs_put_client(clp);
	if (clp != old) {
		clp->cl_preserve_clid = true;
		clp = old;
	}

	return clp;

error:
	nfs_mark_client_ready(clp, error);
	nfs_put_client(clp);
	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
	return ERR_PTR(error);
}

/*
 * SETCLIENTID just did a callback update with the callback ident in
 * "drop," but server trunking discovery claims "drop" and "keep" are
 * actually the same server.  Swap the callback IDs so that "keep"
 * will continue to use the callback ident the server now knows about,
 * and so that "keep"'s original callback ident is destroyed when
 * "drop" is freed.
 */
static void nfs4_swap_callback_idents(struct nfs_client *keep,
				      struct nfs_client *drop)
{
	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
	unsigned int save = keep->cl_cb_ident;

	if (keep->cl_cb_ident == drop->cl_cb_ident)
		return;

	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
		__func__, keep->cl_cb_ident, drop->cl_cb_ident);

	spin_lock(&nn->nfs_client_lock);

	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
	keep->cl_cb_ident = drop->cl_cb_ident;

	idr_replace(&nn->cb_ident_idr, drop, save);
	drop->cl_cb_ident = save;

	spin_unlock(&nn->nfs_client_lock);
}

/**
 * nfs40_walk_client_list - Find server that recognizes a client ID
 *
 * @new: nfs_client with client ID to test
 * @result: OUT: found nfs_client, or new
 * @cred: credential to use for trunking test
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status.
 * If zero is returned, an nfs_client pointer is planted in "result."
 *
 * NB: nfs40_walk_client_list() relies on the new nfs_client being
 *     the last nfs_client on the list.
 */
int nfs40_walk_client_list(struct nfs_client *new,
			   struct nfs_client **result,
			   struct rpc_cred *cred)
{
	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
	struct nfs_client *pos, *n, *prev = NULL;
	struct nfs4_setclientid_res clid = {
		.clientid	= new->cl_clientid,
		.confirm	= new->cl_confirm,
	};
	int status = -NFS4ERR_STALE_CLIENTID;

	spin_lock(&nn->nfs_client_lock);
	list_for_each_entry_safe(pos, n, &nn->nfs_client_list, cl_share_link) {
		/* If "pos" isn't marked ready, we can't trust the
		 * remaining fields in "pos" */
		if (pos->cl_cons_state < NFS_CS_READY)
			continue;

		if (pos->rpc_ops != new->rpc_ops)
			continue;

		if (pos->cl_proto != new->cl_proto)
			continue;

		if (pos->cl_minorversion != new->cl_minorversion)
			continue;

		if (pos->cl_clientid != new->cl_clientid)
			continue;

		atomic_inc(&pos->cl_count);
		spin_unlock(&nn->nfs_client_lock);

		if (prev)
			nfs_put_client(prev);
		prev = pos;

		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
		switch (status) {
		case -NFS4ERR_STALE_CLIENTID:
			break;
		case 0:
			nfs4_swap_callback_idents(pos, new);

			prev = NULL;
			*result = pos;
			dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
				__func__, pos, atomic_read(&pos->cl_count));
		default:
			goto out;
		}

		spin_lock(&nn->nfs_client_lock);
	}
	spin_unlock(&nn->nfs_client_lock);

	/* No match found. The server lost our clientid */
out:
	if (prev)
		nfs_put_client(prev);
	dprintk("NFS: <-- %s status = %d\n", __func__, status);
	return status;
}

#ifdef CONFIG_NFS_V4_1
/*
 * Returns true if the client IDs match
 */
static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
{
	if (a->cl_clientid != b->cl_clientid) {
		dprintk("NFS: --> %s client ID %llx does not match %llx\n",
			__func__, a->cl_clientid, b->cl_clientid);
		return false;
	}
	dprintk("NFS: --> %s client ID %llx matches %llx\n",
		__func__, a->cl_clientid, b->cl_clientid);
	return true;
}

/*
 * Returns true if the server owners match
 */
static bool
nfs4_match_serverowners(struct nfs_client *a, struct nfs_client *b)
{
	struct nfs41_server_owner *o1 = a->cl_serverowner;
	struct nfs41_server_owner *o2 = b->cl_serverowner;

	if (o1->minor_id != o2->minor_id) {
		dprintk("NFS: --> %s server owner minor IDs do not match\n",
			__func__);
		return false;
	}

	if (o1->major_id_sz != o2->major_id_sz)
		goto out_major_mismatch;
	if (memcmp(o1->major_id, o2->major_id, o1->major_id_sz) != 0)
		goto out_major_mismatch;

	dprintk("NFS: --> %s server owners match\n", __func__);
	return true;

out_major_mismatch:
	dprintk("NFS: --> %s server owner major IDs do not match\n",
		__func__);
	return false;
}

/**
 * nfs41_walk_client_list - Find nfs_client that matches a client/server owner
 *
 * @new: nfs_client with client ID to test
 * @result: OUT: found nfs_client, or new
 * @cred: credential to use for trunking test
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status.
 * If zero is returned, an nfs_client pointer is planted in "result."
 *
 * NB: nfs41_walk_client_list() relies on the new nfs_client being
 *     the last nfs_client on the list.
 */
int nfs41_walk_client_list(struct nfs_client *new,
			   struct nfs_client **result,
			   struct rpc_cred *cred)
{
	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
	struct nfs_client *pos, *n, *prev = NULL;
	int status = -NFS4ERR_STALE_CLIENTID;

	spin_lock(&nn->nfs_client_lock);
	list_for_each_entry_safe(pos, n, &nn->nfs_client_list, cl_share_link) {
		/* If "pos" isn't marked ready, we can't trust the
		 * remaining fields in "pos", especially the client
		 * ID and serverowner fields.  Wait for CREATE_SESSION
		 * to finish. */
		if (pos->cl_cons_state < NFS_CS_READY) {
			atomic_inc(&pos->cl_count);
			spin_unlock(&nn->nfs_client_lock);

			if (prev)
				nfs_put_client(prev);
			prev = pos;

			nfs4_schedule_lease_recovery(pos);
			status = nfs_wait_client_init_complete(pos);
			if (status < 0) {
				nfs_put_client(pos);
				spin_lock(&nn->nfs_client_lock);
				continue;
			}
			status = pos->cl_cons_state;
			spin_lock(&nn->nfs_client_lock);
			if (status < 0)
				continue;
		}

		if (pos->rpc_ops != new->rpc_ops)
			continue;

		if (pos->cl_proto != new->cl_proto)
			continue;

		if (pos->cl_minorversion != new->cl_minorversion)
			continue;

		if (!nfs4_match_clientids(pos, new))
			continue;

		if (!nfs4_match_serverowners(pos, new))
			continue;

		atomic_inc(&pos->cl_count);
		spin_unlock(&nn->nfs_client_lock);
		dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
			__func__, pos, atomic_read(&pos->cl_count));

		*result = pos;
		return 0;
	}

	/* No matching nfs_client found. */
	spin_unlock(&nn->nfs_client_lock);
	dprintk("NFS: <-- %s status = %d\n", __func__, status);
	return status;
}
#endif	/* CONFIG_NFS_V4_1 */

static void nfs4_destroy_server(struct nfs_server *server)
{
	nfs_server_return_all_delegations(server);
	unset_pnfs_layoutdriver(server);
	nfs4_purge_state_owners(server);
}

/*
 * NFSv4.0 callback thread helper
 *
 * Find a client by callback identifier
 */
struct nfs_client *
nfs4_find_client_ident(struct net *net, int cb_ident)
{
	struct nfs_client *clp;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	spin_lock(&nn->nfs_client_lock);
	clp = idr_find(&nn->cb_ident_idr, cb_ident);
	if (clp)
		atomic_inc(&clp->cl_count);
	spin_unlock(&nn->nfs_client_lock);
	return clp;
}

#if defined(CONFIG_NFS_V4_1)
/* Common match routine for v4.0 and v4.1 callback services */
static bool nfs4_cb_match_client(const struct sockaddr *addr,
		struct nfs_client *clp, u32 minorversion)
{
	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;

	/* Don't match clients that failed to initialise */
	if (!(clp->cl_cons_state == NFS_CS_READY ||
	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
		return false;

	smp_rmb();

	/* Match the version and minorversion */
	if (clp->rpc_ops->version != 4 ||
	    clp->cl_minorversion != minorversion)
		return false;

	/* Match only the IP address, not the port number */
	if (!nfs_sockaddr_match_ipaddr(addr, clap))
		return false;

	return true;
}

/*
 * NFSv4.1 callback thread helper
 * For CB_COMPOUND calls, find a client by IP address, protocol version,
 * minorversion, and sessionID
 *
 * Returns NULL if no such client
 */
struct nfs_client *
nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
			   struct nfs4_sessionid *sid)
{
	struct nfs_client *clp;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	spin_lock(&nn->nfs_client_lock);
	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
		if (nfs4_cb_match_client(addr, clp, 1) == false)
			continue;

		if (!nfs4_has_session(clp))
			continue;

		/* Match sessionid*/
		if (memcmp(clp->cl_session->sess_id.data,
		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
			continue;

		atomic_inc(&clp->cl_count);
		spin_unlock(&nn->nfs_client_lock);
		return clp;
	}
	spin_unlock(&nn->nfs_client_lock);
	return NULL;
}

#else /* CONFIG_NFS_V4_1 */

struct nfs_client *
nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
			   struct nfs4_sessionid *sid)
{
	return NULL;
}
#endif /* CONFIG_NFS_V4_1 */

/*
 * Set up an NFS4 client
 */
static int nfs4_set_client(struct nfs_server *server,
		const char *hostname,
		const struct sockaddr *addr,
		const size_t addrlen,
		const char *ip_addr,
		rpc_authflavor_t authflavour,
		int proto, const struct rpc_timeout *timeparms,
		u32 minorversion, struct net *net)
{
	struct nfs_client_initdata cl_init = {
		.hostname = hostname,
		.addr = addr,
		.addrlen = addrlen,
		.nfs_mod = &nfs_v4,
		.proto = proto,
		.minorversion = minorversion,
		.net = net,
	};
	struct nfs_client *clp;
	int error;

	dprintk("--> nfs4_set_client()\n");

	if (server->flags & NFS_MOUNT_NORESVPORT)
		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);

	/* Allocate or find a client reference we can use */
	clp = nfs_get_client(&cl_init, timeparms, ip_addr, authflavour);
	if (IS_ERR(clp)) {
		error = PTR_ERR(clp);
		goto error;
	}

	/*
	 * Query for the lease time on clientid setup or renewal
	 *
	 * Note that this will be set on nfs_clients that were created
	 * only for the DS role and did not set this bit, but now will
	 * serve a dual role.
	 */
	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);

	server->nfs_client = clp;
	dprintk("<-- nfs4_set_client() = 0 [new %p]\n", clp);
	return 0;
error:
	dprintk("<-- nfs4_set_client() = xerror %d\n", error);
	return error;
}

/*
 * Set up a pNFS Data Server client.
 *
 * Return any existing nfs_client that matches server address,port,version
 * and minorversion.
 *
 * For a new nfs_client, use a soft mount (default), a low retrans and a
 * low timeout interval so that if a connection is lost, we retry through
 * the MDS.
 */
struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,
		const struct sockaddr *ds_addr, int ds_addrlen,
		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans)
{
	struct nfs_client_initdata cl_init = {
		.addr = ds_addr,
		.addrlen = ds_addrlen,
		.nfs_mod = &nfs_v4,
		.proto = ds_proto,
		.minorversion = mds_clp->cl_minorversion,
		.net = mds_clp->cl_net,
	};
	struct rpc_timeout ds_timeout;
	struct nfs_client *clp;

	/*
	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
	 * (section 13.1 RFC 5661).
	 */
	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
	clp = nfs_get_client(&cl_init, &ds_timeout, mds_clp->cl_ipaddr,
			     mds_clp->cl_rpcclient->cl_auth->au_flavor);

	dprintk("<-- %s %p\n", __func__, clp);
	return clp;
}
EXPORT_SYMBOL_GPL(nfs4_set_ds_client);

/*
 * Session has been established, and the client marked ready.
 * Set the mount rsize and wsize with negotiated fore channel
 * attributes which will be bound checked in nfs_server_set_fsinfo.
 */
static void nfs4_session_set_rwsize(struct nfs_server *server)
{
#ifdef CONFIG_NFS_V4_1
	struct nfs4_session *sess;
	u32 server_resp_sz;
	u32 server_rqst_sz;

	if (!nfs4_has_session(server->nfs_client))
		return;
	sess = server->nfs_client->cl_session;
	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;

	if (server->rsize > server_resp_sz)
		server->rsize = server_resp_sz;
	if (server->wsize > server_rqst_sz)
		server->wsize = server_rqst_sz;
#endif /* CONFIG_NFS_V4_1 */
}

static int nfs4_server_common_setup(struct nfs_server *server,
		struct nfs_fh *mntfh)
{
	struct nfs_fattr *fattr;
	int error;

	/* data servers support only a subset of NFSv4.1 */
	if (is_ds_only_client(server->nfs_client))
		return -EPROTONOSUPPORT;

	fattr = nfs_alloc_fattr();
	if (fattr == NULL)
		return -ENOMEM;

	/* We must ensure the session is initialised first */
	error = nfs4_init_session(server);
	if (error < 0)
		goto out;

	/* Probe the root fh to retrieve its FSID and filehandle */
	error = nfs4_get_rootfh(server, mntfh);
	if (error < 0)
		goto out;

	dprintk("Server FSID: %llx:%llx\n",
			(unsigned long long) server->fsid.major,
			(unsigned long long) server->fsid.minor);
	dprintk("Mount FH: %d\n", mntfh->size);

	nfs4_session_set_rwsize(server);

	error = nfs_probe_fsinfo(server, mntfh, fattr);
	if (error < 0)
		goto out;

	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
		server->namelen = NFS4_MAXNAMLEN;

	nfs_server_insert_lists(server);
	server->mount_time = jiffies;
	server->destroy = nfs4_destroy_server;
out:
	nfs_free_fattr(fattr);
	return error;
}

/*
 * Create a version 4 volume record
 */
static int nfs4_init_server(struct nfs_server *server,
		const struct nfs_parsed_mount_data *data)
{
	struct rpc_timeout timeparms;
	int error;

	dprintk("--> nfs4_init_server()\n");

	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
			data->timeo, data->retrans);

	/* Initialise the client representation from the mount data */
	server->flags = data->flags;
	server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR|NFS_CAP_POSIX_LOCK;
	if (!(data->flags & NFS_MOUNT_NORDIRPLUS))
			server->caps |= NFS_CAP_READDIRPLUS;
	server->options = data->options;

	/* Get a client record */
	error = nfs4_set_client(server,
			data->nfs_server.hostname,
			(const struct sockaddr *)&data->nfs_server.address,
			data->nfs_server.addrlen,
			data->client_address,
			data->auth_flavors[0],
			data->nfs_server.protocol,
			&timeparms,
			data->minorversion,
			data->net);
	if (error < 0)
		goto error;

	/*
	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
	 * authentication.
	 */
	if (nfs4_disable_idmapping && data->auth_flavors[0] == RPC_AUTH_UNIX)
		server->caps |= NFS_CAP_UIDGID_NOMAP;

	if (data->rsize)
		server->rsize = nfs_block_size(data->rsize, NULL);
	if (data->wsize)
		server->wsize = nfs_block_size(data->wsize, NULL);

	server->acregmin = data->acregmin * HZ;
	server->acregmax = data->acregmax * HZ;
	server->acdirmin = data->acdirmin * HZ;
	server->acdirmax = data->acdirmax * HZ;

	server->port = data->nfs_server.port;

	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);

error:
	/* Done */
	dprintk("<-- nfs4_init_server() = %d\n", error);
	return error;
}

/*
 * Create a version 4 volume record
 * - keyed on server and FSID
 */
/*struct nfs_server *nfs4_create_server(const struct nfs_parsed_mount_data *data,
				      struct nfs_fh *mntfh)*/
struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
				      struct nfs_subversion *nfs_mod)
{
	struct nfs_server *server;
	int error;

	dprintk("--> nfs4_create_server()\n");

	server = nfs_alloc_server();
	if (!server)
		return ERR_PTR(-ENOMEM);

	/* set up the general RPC client */
	error = nfs4_init_server(server, mount_info->parsed);
	if (error < 0)
		goto error;

	error = nfs4_server_common_setup(server, mount_info->mntfh);
	if (error < 0)
		goto error;

	dprintk("<-- nfs4_create_server() = %p\n", server);
	return server;

error:
	nfs_free_server(server);
	dprintk("<-- nfs4_create_server() = error %d\n", error);
	return ERR_PTR(error);
}

/*
 * Create an NFS4 referral server record
 */
struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
					       struct nfs_fh *mntfh)
{
	struct nfs_client *parent_client;
	struct nfs_server *server, *parent_server;
	int error;

	dprintk("--> nfs4_create_referral_server()\n");

	server = nfs_alloc_server();
	if (!server)
		return ERR_PTR(-ENOMEM);

	parent_server = NFS_SB(data->sb);
	parent_client = parent_server->nfs_client;

	/* Initialise the client representation from the parent server */
	nfs_server_copy_userdata(server, parent_server);
	server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR;

	/* Get a client representation.
	 * Note: NFSv4 always uses TCP, */
	error = nfs4_set_client(server, data->hostname,
				data->addr,
				data->addrlen,
				parent_client->cl_ipaddr,
				data->authflavor,
				rpc_protocol(parent_server->client),
				parent_server->client->cl_timeout,
				parent_client->cl_mvops->minor_version,
				parent_client->cl_net);
	if (error < 0)
		goto error;

	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout, data->authflavor);
	if (error < 0)
		goto error;

	error = nfs4_server_common_setup(server, mntfh);
	if (error < 0)
		goto error;

	dprintk("<-- nfs_create_referral_server() = %p\n", server);
	return server;

error:
	nfs_free_server(server);
	dprintk("<-- nfs4_create_referral_server() = error %d\n", error);
	return ERR_PTR(error);
}