summaryrefslogtreecommitdiff
path: root/fs/cifs/cifs_swn.c
blob: 180c234c2f46c26d09df18f064752937647a2375 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Witness Service client for CIFS
 *
 * Copyright (c) 2020 Samuel Cabrero <scabrero@suse.de>
 */

#include <linux/kref.h>
#include <net/genetlink.h>
#include <uapi/linux/cifs/cifs_netlink.h>

#include "cifs_swn.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "fscache.h"
#include "cifs_debug.h"
#include "netlink.h"

static DEFINE_IDR(cifs_swnreg_idr);
static DEFINE_MUTEX(cifs_swnreg_idr_mutex);

struct cifs_swn_reg {
	int id;
	struct kref ref_count;

	const char *net_name;
	const char *share_name;
	bool net_name_notify;
	bool share_name_notify;
	bool ip_notify;

	struct cifs_tcon *tcon;
};

static int cifs_swn_auth_info_krb(struct cifs_tcon *tcon, struct sk_buff *skb)
{
	int ret;

	ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_KRB_AUTH);
	if (ret < 0)
		return ret;

	return 0;
}

static int cifs_swn_auth_info_ntlm(struct cifs_tcon *tcon, struct sk_buff *skb)
{
	int ret;

	if (tcon->ses->user_name != NULL) {
		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_USER_NAME, tcon->ses->user_name);
		if (ret < 0)
			return ret;
	}

	if (tcon->ses->password != NULL) {
		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_PASSWORD, tcon->ses->password);
		if (ret < 0)
			return ret;
	}

	if (tcon->ses->domainName != NULL) {
		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_DOMAIN_NAME, tcon->ses->domainName);
		if (ret < 0)
			return ret;
	}

	return 0;
}

/*
 * Sends a register message to the userspace daemon based on the registration.
 * The authentication information to connect to the witness service is bundled
 * into the message.
 */
static int cifs_swn_send_register_message(struct cifs_swn_reg *swnreg)
{
	struct sk_buff *skb;
	struct genlmsghdr *hdr;
	enum securityEnum authtype;
	struct sockaddr_storage *addr;
	int ret;

	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (skb == NULL) {
		ret = -ENOMEM;
		goto fail;
	}

	hdr = genlmsg_put(skb, 0, 0, &cifs_genl_family, 0, CIFS_GENL_CMD_SWN_REGISTER);
	if (hdr == NULL) {
		ret = -ENOMEM;
		goto nlmsg_fail;
	}

	ret = nla_put_u32(skb, CIFS_GENL_ATTR_SWN_REGISTRATION_ID, swnreg->id);
	if (ret < 0)
		goto nlmsg_fail;

	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_NET_NAME, swnreg->net_name);
	if (ret < 0)
		goto nlmsg_fail;

	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME, swnreg->share_name);
	if (ret < 0)
		goto nlmsg_fail;

	/*
	 * If there is an address stored use it instead of the server address, because we are
	 * in the process of reconnecting to it after a share has been moved or we have been
	 * told to switch to it (client move message). In these cases we unregister from the
	 * server address and register to the new address when we receive the notification.
	 */
	if (swnreg->tcon->ses->server->use_swn_dstaddr)
		addr = &swnreg->tcon->ses->server->swn_dstaddr;
	else
		addr = &swnreg->tcon->ses->server->dstaddr;

	ret = nla_put(skb, CIFS_GENL_ATTR_SWN_IP, sizeof(struct sockaddr_storage), addr);
	if (ret < 0)
		goto nlmsg_fail;

	if (swnreg->net_name_notify) {
		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_NET_NAME_NOTIFY);
		if (ret < 0)
			goto nlmsg_fail;
	}

	if (swnreg->share_name_notify) {
		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME_NOTIFY);
		if (ret < 0)
			goto nlmsg_fail;
	}

	if (swnreg->ip_notify) {
		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_IP_NOTIFY);
		if (ret < 0)
			goto nlmsg_fail;
	}

	authtype = cifs_select_sectype(swnreg->tcon->ses->server, swnreg->tcon->ses->sectype);
	switch (authtype) {
	case Kerberos:
		ret = cifs_swn_auth_info_krb(swnreg->tcon, skb);
		if (ret < 0) {
			cifs_dbg(VFS, "%s: Failed to get kerberos auth info: %d\n", __func__, ret);
			goto nlmsg_fail;
		}
		break;
	case NTLMv2:
	case RawNTLMSSP:
		ret = cifs_swn_auth_info_ntlm(swnreg->tcon, skb);
		if (ret < 0) {
			cifs_dbg(VFS, "%s: Failed to get NTLM auth info: %d\n", __func__, ret);
			goto nlmsg_fail;
		}
		break;
	default:
		cifs_dbg(VFS, "%s: secType %d not supported!\n", __func__, authtype);
		ret = -EINVAL;
		goto nlmsg_fail;
	}

	genlmsg_end(skb, hdr);
	genlmsg_multicast(&cifs_genl_family, skb, 0, CIFS_GENL_MCGRP_SWN, GFP_ATOMIC);

	cifs_dbg(FYI, "%s: Message to register for network name %s with id %d sent\n", __func__,
			swnreg->net_name, swnreg->id);

	return 0;

nlmsg_fail:
	genlmsg_cancel(skb, hdr);
	nlmsg_free(skb);
fail:
	return ret;
}

/*
 * Sends an uregister message to the userspace daemon based on the registration
 */
static int cifs_swn_send_unregister_message(struct cifs_swn_reg *swnreg)
{
	struct sk_buff *skb;
	struct genlmsghdr *hdr;
	int ret;

	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (skb == NULL)
		return -ENOMEM;

	hdr = genlmsg_put(skb, 0, 0, &cifs_genl_family, 0, CIFS_GENL_CMD_SWN_UNREGISTER);
	if (hdr == NULL) {
		ret = -ENOMEM;
		goto nlmsg_fail;
	}

	ret = nla_put_u32(skb, CIFS_GENL_ATTR_SWN_REGISTRATION_ID, swnreg->id);
	if (ret < 0)
		goto nlmsg_fail;

	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_NET_NAME, swnreg->net_name);
	if (ret < 0)
		goto nlmsg_fail;

	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME, swnreg->share_name);
	if (ret < 0)
		goto nlmsg_fail;

	ret = nla_put(skb, CIFS_GENL_ATTR_SWN_IP, sizeof(struct sockaddr_storage),
			&swnreg->tcon->ses->server->dstaddr);
	if (ret < 0)
		goto nlmsg_fail;

	if (swnreg->net_name_notify) {
		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_NET_NAME_NOTIFY);
		if (ret < 0)
			goto nlmsg_fail;
	}

	if (swnreg->share_name_notify) {
		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME_NOTIFY);
		if (ret < 0)
			goto nlmsg_fail;
	}

	if (swnreg->ip_notify) {
		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_IP_NOTIFY);
		if (ret < 0)
			goto nlmsg_fail;
	}

	genlmsg_end(skb, hdr);
	genlmsg_multicast(&cifs_genl_family, skb, 0, CIFS_GENL_MCGRP_SWN, GFP_ATOMIC);

	cifs_dbg(FYI, "%s: Message to unregister for network name %s with id %d sent\n", __func__,
			swnreg->net_name, swnreg->id);

	return 0;

nlmsg_fail:
	genlmsg_cancel(skb, hdr);
	nlmsg_free(skb);
	return ret;
}

/*
 * Try to find a matching registration for the tcon's server name and share name.
 * Calls to this function must be protected by cifs_swnreg_idr_mutex.
 * TODO Try to avoid memory allocations
 */
static struct cifs_swn_reg *cifs_find_swn_reg(struct cifs_tcon *tcon)
{
	struct cifs_swn_reg *swnreg;
	int id;
	const char *share_name;
	const char *net_name;

	net_name = extract_hostname(tcon->treeName);
	if (IS_ERR(net_name)) {
		int ret;

		ret = PTR_ERR(net_name);
		cifs_dbg(VFS, "%s: failed to extract host name from target '%s': %d\n",
				__func__, tcon->treeName, ret);
		return ERR_PTR(-EINVAL);
	}

	share_name = extract_sharename(tcon->treeName);
	if (IS_ERR(share_name)) {
		int ret;

		ret = PTR_ERR(share_name);
		cifs_dbg(VFS, "%s: failed to extract share name from target '%s': %d\n",
				__func__, tcon->treeName, ret);
		kfree(net_name);
		return ERR_PTR(-EINVAL);
	}

	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
		if (strcasecmp(swnreg->net_name, net_name) != 0
		    || strcasecmp(swnreg->share_name, share_name) != 0) {
			continue;
		}

		cifs_dbg(FYI, "Existing swn registration for %s:%s found\n", swnreg->net_name,
				swnreg->share_name);

		kfree(net_name);
		kfree(share_name);

		return swnreg;
	}

	kfree(net_name);
	kfree(share_name);

	return ERR_PTR(-EEXIST);
}

/*
 * Get a registration for the tcon's server and share name, allocating a new one if it does not
 * exists
 */
static struct cifs_swn_reg *cifs_get_swn_reg(struct cifs_tcon *tcon)
{
	struct cifs_swn_reg *reg = NULL;
	int ret;

	mutex_lock(&cifs_swnreg_idr_mutex);

	/* Check if we are already registered for this network and share names */
	reg = cifs_find_swn_reg(tcon);
	if (!IS_ERR(reg)) {
		kref_get(&reg->ref_count);
		mutex_unlock(&cifs_swnreg_idr_mutex);
		return reg;
	} else if (PTR_ERR(reg) != -EEXIST) {
		mutex_unlock(&cifs_swnreg_idr_mutex);
		return reg;
	}

	reg = kmalloc(sizeof(struct cifs_swn_reg), GFP_ATOMIC);
	if (reg == NULL) {
		mutex_unlock(&cifs_swnreg_idr_mutex);
		return ERR_PTR(-ENOMEM);
	}

	kref_init(&reg->ref_count);

	reg->id = idr_alloc(&cifs_swnreg_idr, reg, 1, 0, GFP_ATOMIC);
	if (reg->id < 0) {
		cifs_dbg(FYI, "%s: failed to allocate registration id\n", __func__);
		ret = reg->id;
		goto fail;
	}

	reg->net_name = extract_hostname(tcon->treeName);
	if (IS_ERR(reg->net_name)) {
		ret = PTR_ERR(reg->net_name);
		cifs_dbg(VFS, "%s: failed to extract host name from target: %d\n", __func__, ret);
		goto fail_idr;
	}

	reg->share_name = extract_sharename(tcon->treeName);
	if (IS_ERR(reg->share_name)) {
		ret = PTR_ERR(reg->share_name);
		cifs_dbg(VFS, "%s: failed to extract share name from target: %d\n", __func__, ret);
		goto fail_net_name;
	}

	reg->net_name_notify = true;
	reg->share_name_notify = true;
	reg->ip_notify = (tcon->capabilities & SMB2_SHARE_CAP_SCALEOUT);

	reg->tcon = tcon;

	mutex_unlock(&cifs_swnreg_idr_mutex);

	return reg;

fail_net_name:
	kfree(reg->net_name);
fail_idr:
	idr_remove(&cifs_swnreg_idr, reg->id);
fail:
	kfree(reg);
	mutex_unlock(&cifs_swnreg_idr_mutex);
	return ERR_PTR(ret);
}

static void cifs_swn_reg_release(struct kref *ref)
{
	struct cifs_swn_reg *swnreg = container_of(ref, struct cifs_swn_reg, ref_count);
	int ret;

	ret = cifs_swn_send_unregister_message(swnreg);
	if (ret < 0)
		cifs_dbg(VFS, "%s: Failed to send unregister message: %d\n", __func__, ret);

	idr_remove(&cifs_swnreg_idr, swnreg->id);
	kfree(swnreg->net_name);
	kfree(swnreg->share_name);
	kfree(swnreg);
}

static void cifs_put_swn_reg(struct cifs_swn_reg *swnreg)
{
	mutex_lock(&cifs_swnreg_idr_mutex);
	kref_put(&swnreg->ref_count, cifs_swn_reg_release);
	mutex_unlock(&cifs_swnreg_idr_mutex);
}

static int cifs_swn_resource_state_changed(struct cifs_swn_reg *swnreg, const char *name, int state)
{
	switch (state) {
	case CIFS_SWN_RESOURCE_STATE_UNAVAILABLE:
		cifs_dbg(FYI, "%s: resource name '%s' become unavailable\n", __func__, name);
		cifs_signal_cifsd_for_reconnect(swnreg->tcon->ses->server, true);
		break;
	case CIFS_SWN_RESOURCE_STATE_AVAILABLE:
		cifs_dbg(FYI, "%s: resource name '%s' become available\n", __func__, name);
		cifs_signal_cifsd_for_reconnect(swnreg->tcon->ses->server, true);
		break;
	case CIFS_SWN_RESOURCE_STATE_UNKNOWN:
		cifs_dbg(FYI, "%s: resource name '%s' changed to unknown state\n", __func__, name);
		break;
	}
	return 0;
}

static bool cifs_sockaddr_equal(struct sockaddr_storage *addr1, struct sockaddr_storage *addr2)
{
	if (addr1->ss_family != addr2->ss_family)
		return false;

	if (addr1->ss_family == AF_INET) {
		return (memcmp(&((const struct sockaddr_in *)addr1)->sin_addr,
				&((const struct sockaddr_in *)addr2)->sin_addr,
				sizeof(struct in_addr)) == 0);
	}

	if (addr1->ss_family == AF_INET6) {
		return (memcmp(&((const struct sockaddr_in6 *)addr1)->sin6_addr,
				&((const struct sockaddr_in6 *)addr2)->sin6_addr,
				sizeof(struct in6_addr)) == 0);
	}

	return false;
}

static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
				   const struct sockaddr_storage *old,
				   struct sockaddr_storage *dst)
{
	__be16 port = cpu_to_be16(CIFS_PORT);

	if (old->ss_family == AF_INET) {
		struct sockaddr_in *ipv4 = (struct sockaddr_in *)old;

		port = ipv4->sin_port;
	} else if (old->ss_family == AF_INET6) {
		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)old;

		port = ipv6->sin6_port;
	}

	if (new->ss_family == AF_INET) {
		struct sockaddr_in *ipv4 = (struct sockaddr_in *)new;

		ipv4->sin_port = port;
	} else if (new->ss_family == AF_INET6) {
		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)new;

		ipv6->sin6_port = port;
	}

	*dst = *new;

	return 0;
}

static int cifs_swn_reconnect(struct cifs_tcon *tcon, struct sockaddr_storage *addr)
{
	int ret = 0;

	/* Store the reconnect address */
	mutex_lock(&tcon->ses->server->srv_mutex);
	if (cifs_sockaddr_equal(&tcon->ses->server->dstaddr, addr))
		goto unlock;

	ret = cifs_swn_store_swn_addr(addr, &tcon->ses->server->dstaddr,
				      &tcon->ses->server->swn_dstaddr);
	if (ret < 0) {
		cifs_dbg(VFS, "%s: failed to store address: %d\n", __func__, ret);
		goto unlock;
	}
	tcon->ses->server->use_swn_dstaddr = true;

	/*
	 * Unregister to stop receiving notifications for the old IP address.
	 */
	ret = cifs_swn_unregister(tcon);
	if (ret < 0) {
		cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
			 __func__, ret);
		goto unlock;
	}

	/*
	 * And register to receive notifications for the new IP address now that we have
	 * stored the new address.
	 */
	ret = cifs_swn_register(tcon);
	if (ret < 0) {
		cifs_dbg(VFS, "%s: Failed to register for witness notifications: %d\n",
			 __func__, ret);
		goto unlock;
	}

	cifs_signal_cifsd_for_reconnect(tcon->ses->server, false);

unlock:
	mutex_unlock(&tcon->ses->server->srv_mutex);

	return ret;
}

static int cifs_swn_client_move(struct cifs_swn_reg *swnreg, struct sockaddr_storage *addr)
{
	struct sockaddr_in *ipv4 = (struct sockaddr_in *)addr;
	struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)addr;

	if (addr->ss_family == AF_INET)
		cifs_dbg(FYI, "%s: move to %pI4\n", __func__, &ipv4->sin_addr);
	else if (addr->ss_family == AF_INET6)
		cifs_dbg(FYI, "%s: move to %pI6\n", __func__, &ipv6->sin6_addr);

	return cifs_swn_reconnect(swnreg->tcon, addr);
}

int cifs_swn_notify(struct sk_buff *skb, struct genl_info *info)
{
	struct cifs_swn_reg *swnreg;
	char name[256];
	int type;

	if (info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]) {
		int swnreg_id;

		swnreg_id = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]);
		mutex_lock(&cifs_swnreg_idr_mutex);
		swnreg = idr_find(&cifs_swnreg_idr, swnreg_id);
		mutex_unlock(&cifs_swnreg_idr_mutex);
		if (swnreg == NULL) {
			cifs_dbg(FYI, "%s: registration id %d not found\n", __func__, swnreg_id);
			return -EINVAL;
		}
	} else {
		cifs_dbg(FYI, "%s: missing registration id attribute\n", __func__);
		return -EINVAL;
	}

	if (info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]) {
		type = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]);
	} else {
		cifs_dbg(FYI, "%s: missing notification type attribute\n", __func__);
		return -EINVAL;
	}

	switch (type) {
	case CIFS_SWN_NOTIFICATION_RESOURCE_CHANGE: {
		int state;

		if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME]) {
			nla_strscpy(name, info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME],
					sizeof(name));
		} else {
			cifs_dbg(FYI, "%s: missing resource name attribute\n", __func__);
			return -EINVAL;
		}
		if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]) {
			state = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]);
		} else {
			cifs_dbg(FYI, "%s: missing resource state attribute\n", __func__);
			return -EINVAL;
		}
		return cifs_swn_resource_state_changed(swnreg, name, state);
	}
	case CIFS_SWN_NOTIFICATION_CLIENT_MOVE: {
		struct sockaddr_storage addr;

		if (info->attrs[CIFS_GENL_ATTR_SWN_IP]) {
			nla_memcpy(&addr, info->attrs[CIFS_GENL_ATTR_SWN_IP], sizeof(addr));
		} else {
			cifs_dbg(FYI, "%s: missing IP address attribute\n", __func__);
			return -EINVAL;
		}
		return cifs_swn_client_move(swnreg, &addr);
	}
	default:
		cifs_dbg(FYI, "%s: unknown notification type %d\n", __func__, type);
		break;
	}

	return 0;
}

int cifs_swn_register(struct cifs_tcon *tcon)
{
	struct cifs_swn_reg *swnreg;
	int ret;

	swnreg = cifs_get_swn_reg(tcon);
	if (IS_ERR(swnreg))
		return PTR_ERR(swnreg);

	ret = cifs_swn_send_register_message(swnreg);
	if (ret < 0) {
		cifs_dbg(VFS, "%s: Failed to send swn register message: %d\n", __func__, ret);
		/* Do not put the swnreg or return error, the echo task will retry */
	}

	return 0;
}

int cifs_swn_unregister(struct cifs_tcon *tcon)
{
	struct cifs_swn_reg *swnreg;

	mutex_lock(&cifs_swnreg_idr_mutex);

	swnreg = cifs_find_swn_reg(tcon);
	if (IS_ERR(swnreg)) {
		mutex_unlock(&cifs_swnreg_idr_mutex);
		return PTR_ERR(swnreg);
	}

	mutex_unlock(&cifs_swnreg_idr_mutex);

	cifs_put_swn_reg(swnreg);

	return 0;
}

void cifs_swn_dump(struct seq_file *m)
{
	struct cifs_swn_reg *swnreg;
	struct sockaddr_in *sa;
	struct sockaddr_in6 *sa6;
	int id;

	seq_puts(m, "Witness registrations:");

	mutex_lock(&cifs_swnreg_idr_mutex);
	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
		seq_printf(m, "\nId: %u Refs: %u Network name: '%s'%s Share name: '%s'%s Ip address: ",
				id, kref_read(&swnreg->ref_count),
				swnreg->net_name, swnreg->net_name_notify ? "(y)" : "(n)",
				swnreg->share_name, swnreg->share_name_notify ? "(y)" : "(n)");
		switch (swnreg->tcon->ses->server->dstaddr.ss_family) {
		case AF_INET:
			sa = (struct sockaddr_in *) &swnreg->tcon->ses->server->dstaddr;
			seq_printf(m, "%pI4", &sa->sin_addr.s_addr);
			break;
		case AF_INET6:
			sa6 = (struct sockaddr_in6 *) &swnreg->tcon->ses->server->dstaddr;
			seq_printf(m, "%pI6", &sa6->sin6_addr.s6_addr);
			if (sa6->sin6_scope_id)
				seq_printf(m, "%%%u", sa6->sin6_scope_id);
			break;
		default:
			seq_puts(m, "(unknown)");
		}
		seq_printf(m, "%s", swnreg->ip_notify ? "(y)" : "(n)");
	}
	mutex_unlock(&cifs_swnreg_idr_mutex);
	seq_puts(m, "\n");
}

void cifs_swn_check(void)
{
	struct cifs_swn_reg *swnreg;
	int id;
	int ret;

	mutex_lock(&cifs_swnreg_idr_mutex);
	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
		ret = cifs_swn_send_register_message(swnreg);
		if (ret < 0)
			cifs_dbg(FYI, "%s: Failed to send register message: %d\n", __func__, ret);
	}
	mutex_unlock(&cifs_swnreg_idr_mutex);
}