xref: /linux/fs/smb/client/cifs_swn.c (revision ba199dc909a20fe62270ae4e93f263987bb9d119)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Witness Service client for CIFS
4  *
5  * Copyright (c) 2020 Samuel Cabrero <scabrero@suse.de>
6  */
7 
8 #include <linux/kref.h>
9 #include <net/genetlink.h>
10 #include <uapi/linux/cifs/cifs_netlink.h>
11 
12 #include "cifs_swn.h"
13 #include "cifsglob.h"
14 #include "cifsproto.h"
15 #include "fscache.h"
16 #include "cifs_debug.h"
17 #include "netlink.h"
18 
19 static DEFINE_IDR(cifs_swnreg_idr);
20 static DEFINE_MUTEX(cifs_swnreg_idr_mutex);
21 
22 struct cifs_swn_reg {
23 	int id;
24 	struct kref ref_count;
25 
26 	const char *net_name;
27 	const char *share_name;
28 	bool net_name_notify;
29 	bool share_name_notify;
30 	bool ip_notify;
31 
32 	struct cifs_tcon *tcon;
33 };
34 
35 static int cifs_swn_auth_info_krb(struct cifs_tcon *tcon, struct sk_buff *skb)
36 {
37 	int ret;
38 
39 	ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_KRB_AUTH);
40 	if (ret < 0)
41 		return ret;
42 
43 	return 0;
44 }
45 
46 static int cifs_swn_auth_info_ntlm(struct cifs_tcon *tcon, struct sk_buff *skb)
47 {
48 	int ret;
49 
50 	if (tcon->ses->user_name != NULL) {
51 		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_USER_NAME, tcon->ses->user_name);
52 		if (ret < 0)
53 			return ret;
54 	}
55 
56 	if (tcon->ses->password != NULL) {
57 		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_PASSWORD, tcon->ses->password);
58 		if (ret < 0)
59 			return ret;
60 	}
61 
62 	if (tcon->ses->domainName != NULL) {
63 		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_DOMAIN_NAME, tcon->ses->domainName);
64 		if (ret < 0)
65 			return ret;
66 	}
67 
68 	return 0;
69 }
70 
71 /*
72  * Sends a register message to the userspace daemon based on the registration.
73  * The authentication information to connect to the witness service is bundled
74  * into the message.
75  */
76 static int cifs_swn_send_register_message(struct cifs_swn_reg *swnreg)
77 {
78 	struct sk_buff *skb;
79 	struct genlmsghdr *hdr;
80 	enum securityEnum authtype;
81 	struct sockaddr_storage *addr;
82 	int ret;
83 
84 	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
85 	if (skb == NULL) {
86 		ret = -ENOMEM;
87 		goto fail;
88 	}
89 
90 	hdr = genlmsg_put(skb, 0, 0, &cifs_genl_family, 0, CIFS_GENL_CMD_SWN_REGISTER);
91 	if (hdr == NULL) {
92 		ret = -ENOMEM;
93 		goto nlmsg_fail;
94 	}
95 
96 	ret = nla_put_u32(skb, CIFS_GENL_ATTR_SWN_REGISTRATION_ID, swnreg->id);
97 	if (ret < 0)
98 		goto nlmsg_fail;
99 
100 	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_NET_NAME, swnreg->net_name);
101 	if (ret < 0)
102 		goto nlmsg_fail;
103 
104 	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME, swnreg->share_name);
105 	if (ret < 0)
106 		goto nlmsg_fail;
107 
108 	/*
109 	 * If there is an address stored use it instead of the server address, because we are
110 	 * in the process of reconnecting to it after a share has been moved or we have been
111 	 * told to switch to it (client move message). In these cases we unregister from the
112 	 * server address and register to the new address when we receive the notification.
113 	 */
114 	if (swnreg->tcon->ses->server->use_swn_dstaddr)
115 		addr = &swnreg->tcon->ses->server->swn_dstaddr;
116 	else
117 		addr = &swnreg->tcon->ses->server->dstaddr;
118 
119 	ret = nla_put(skb, CIFS_GENL_ATTR_SWN_IP, sizeof(struct sockaddr_storage), addr);
120 	if (ret < 0)
121 		goto nlmsg_fail;
122 
123 	if (swnreg->net_name_notify) {
124 		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_NET_NAME_NOTIFY);
125 		if (ret < 0)
126 			goto nlmsg_fail;
127 	}
128 
129 	if (swnreg->share_name_notify) {
130 		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME_NOTIFY);
131 		if (ret < 0)
132 			goto nlmsg_fail;
133 	}
134 
135 	if (swnreg->ip_notify) {
136 		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_IP_NOTIFY);
137 		if (ret < 0)
138 			goto nlmsg_fail;
139 	}
140 
141 	authtype = cifs_select_sectype(swnreg->tcon->ses->server, swnreg->tcon->ses->sectype);
142 	switch (authtype) {
143 	case Kerberos:
144 		ret = cifs_swn_auth_info_krb(swnreg->tcon, skb);
145 		if (ret < 0) {
146 			cifs_dbg(VFS, "%s: Failed to get kerberos auth info: %d\n", __func__, ret);
147 			goto nlmsg_fail;
148 		}
149 		break;
150 	case NTLMv2:
151 	case RawNTLMSSP:
152 		ret = cifs_swn_auth_info_ntlm(swnreg->tcon, skb);
153 		if (ret < 0) {
154 			cifs_dbg(VFS, "%s: Failed to get NTLM auth info: %d\n", __func__, ret);
155 			goto nlmsg_fail;
156 		}
157 		break;
158 	default:
159 		cifs_dbg(VFS, "%s: secType %d not supported!\n", __func__, authtype);
160 		ret = -EINVAL;
161 		goto nlmsg_fail;
162 	}
163 
164 	genlmsg_end(skb, hdr);
165 	genlmsg_multicast(&cifs_genl_family, skb, 0, CIFS_GENL_MCGRP_SWN, GFP_ATOMIC);
166 
167 	cifs_dbg(FYI, "%s: Message to register for network name %s with id %d sent\n", __func__,
168 			swnreg->net_name, swnreg->id);
169 
170 	return 0;
171 
172 nlmsg_fail:
173 	genlmsg_cancel(skb, hdr);
174 	nlmsg_free(skb);
175 fail:
176 	return ret;
177 }
178 
179 /*
180  * Sends an uregister message to the userspace daemon based on the registration
181  */
182 static int cifs_swn_send_unregister_message(struct cifs_swn_reg *swnreg)
183 {
184 	struct sk_buff *skb;
185 	struct genlmsghdr *hdr;
186 	int ret;
187 
188 	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
189 	if (skb == NULL)
190 		return -ENOMEM;
191 
192 	hdr = genlmsg_put(skb, 0, 0, &cifs_genl_family, 0, CIFS_GENL_CMD_SWN_UNREGISTER);
193 	if (hdr == NULL) {
194 		ret = -ENOMEM;
195 		goto nlmsg_fail;
196 	}
197 
198 	ret = nla_put_u32(skb, CIFS_GENL_ATTR_SWN_REGISTRATION_ID, swnreg->id);
199 	if (ret < 0)
200 		goto nlmsg_fail;
201 
202 	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_NET_NAME, swnreg->net_name);
203 	if (ret < 0)
204 		goto nlmsg_fail;
205 
206 	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME, swnreg->share_name);
207 	if (ret < 0)
208 		goto nlmsg_fail;
209 
210 	ret = nla_put(skb, CIFS_GENL_ATTR_SWN_IP, sizeof(struct sockaddr_storage),
211 			&swnreg->tcon->ses->server->dstaddr);
212 	if (ret < 0)
213 		goto nlmsg_fail;
214 
215 	if (swnreg->net_name_notify) {
216 		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_NET_NAME_NOTIFY);
217 		if (ret < 0)
218 			goto nlmsg_fail;
219 	}
220 
221 	if (swnreg->share_name_notify) {
222 		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME_NOTIFY);
223 		if (ret < 0)
224 			goto nlmsg_fail;
225 	}
226 
227 	if (swnreg->ip_notify) {
228 		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_IP_NOTIFY);
229 		if (ret < 0)
230 			goto nlmsg_fail;
231 	}
232 
233 	genlmsg_end(skb, hdr);
234 	genlmsg_multicast(&cifs_genl_family, skb, 0, CIFS_GENL_MCGRP_SWN, GFP_ATOMIC);
235 
236 	cifs_dbg(FYI, "%s: Message to unregister for network name %s with id %d sent\n", __func__,
237 			swnreg->net_name, swnreg->id);
238 
239 	return 0;
240 
241 nlmsg_fail:
242 	genlmsg_cancel(skb, hdr);
243 	nlmsg_free(skb);
244 	return ret;
245 }
246 
247 /*
248  * Try to find a matching registration for the tcon's server name and share name.
249  * Calls to this function must be protected by cifs_swnreg_idr_mutex.
250  * TODO Try to avoid memory allocations
251  */
252 static struct cifs_swn_reg *cifs_find_swn_reg(struct cifs_tcon *tcon)
253 {
254 	struct cifs_swn_reg *swnreg;
255 	int id;
256 	const char *share_name;
257 	const char *net_name;
258 
259 	net_name = extract_hostname(tcon->tree_name);
260 	if (IS_ERR(net_name)) {
261 		int ret;
262 
263 		ret = PTR_ERR(net_name);
264 		cifs_dbg(VFS, "%s: failed to extract host name from target '%s': %d\n",
265 				__func__, tcon->tree_name, ret);
266 		return ERR_PTR(-EINVAL);
267 	}
268 
269 	share_name = extract_sharename(tcon->tree_name);
270 	if (IS_ERR(share_name)) {
271 		int ret;
272 
273 		ret = PTR_ERR(share_name);
274 		cifs_dbg(VFS, "%s: failed to extract share name from target '%s': %d\n",
275 				__func__, tcon->tree_name, ret);
276 		kfree(net_name);
277 		return ERR_PTR(-EINVAL);
278 	}
279 
280 	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
281 		if (strcasecmp(swnreg->net_name, net_name) != 0
282 		    || strcasecmp(swnreg->share_name, share_name) != 0) {
283 			continue;
284 		}
285 
286 		cifs_dbg(FYI, "Existing swn registration for %s:%s found\n", swnreg->net_name,
287 				swnreg->share_name);
288 
289 		kfree(net_name);
290 		kfree(share_name);
291 
292 		return swnreg;
293 	}
294 
295 	kfree(net_name);
296 	kfree(share_name);
297 
298 	return ERR_PTR(-EEXIST);
299 }
300 
301 /*
302  * Get a registration for the tcon's server and share name, allocating a new one if it does not
303  * exists
304  */
305 static struct cifs_swn_reg *cifs_get_swn_reg(struct cifs_tcon *tcon)
306 {
307 	struct cifs_swn_reg *reg = NULL;
308 	int ret;
309 
310 	mutex_lock(&cifs_swnreg_idr_mutex);
311 
312 	/* Check if we are already registered for this network and share names */
313 	reg = cifs_find_swn_reg(tcon);
314 	if (!IS_ERR(reg)) {
315 		kref_get(&reg->ref_count);
316 		mutex_unlock(&cifs_swnreg_idr_mutex);
317 		return reg;
318 	} else if (PTR_ERR(reg) != -EEXIST) {
319 		mutex_unlock(&cifs_swnreg_idr_mutex);
320 		return reg;
321 	}
322 
323 	reg = kmalloc(sizeof(struct cifs_swn_reg), GFP_ATOMIC);
324 	if (reg == NULL) {
325 		mutex_unlock(&cifs_swnreg_idr_mutex);
326 		return ERR_PTR(-ENOMEM);
327 	}
328 
329 	kref_init(&reg->ref_count);
330 
331 	reg->id = idr_alloc(&cifs_swnreg_idr, reg, 1, 0, GFP_ATOMIC);
332 	if (reg->id < 0) {
333 		cifs_dbg(FYI, "%s: failed to allocate registration id\n", __func__);
334 		ret = reg->id;
335 		goto fail;
336 	}
337 
338 	reg->net_name = extract_hostname(tcon->tree_name);
339 	if (IS_ERR(reg->net_name)) {
340 		ret = PTR_ERR(reg->net_name);
341 		cifs_dbg(VFS, "%s: failed to extract host name from target: %d\n", __func__, ret);
342 		goto fail_idr;
343 	}
344 
345 	reg->share_name = extract_sharename(tcon->tree_name);
346 	if (IS_ERR(reg->share_name)) {
347 		ret = PTR_ERR(reg->share_name);
348 		cifs_dbg(VFS, "%s: failed to extract share name from target: %d\n", __func__, ret);
349 		goto fail_net_name;
350 	}
351 
352 	reg->net_name_notify = true;
353 	reg->share_name_notify = true;
354 	reg->ip_notify = (tcon->capabilities & SMB2_SHARE_CAP_SCALEOUT);
355 
356 	reg->tcon = tcon;
357 
358 	mutex_unlock(&cifs_swnreg_idr_mutex);
359 
360 	return reg;
361 
362 fail_net_name:
363 	kfree(reg->net_name);
364 fail_idr:
365 	idr_remove(&cifs_swnreg_idr, reg->id);
366 fail:
367 	kfree(reg);
368 	mutex_unlock(&cifs_swnreg_idr_mutex);
369 	return ERR_PTR(ret);
370 }
371 
372 static void cifs_swn_reg_release(struct kref *ref)
373 {
374 	struct cifs_swn_reg *swnreg = container_of(ref, struct cifs_swn_reg, ref_count);
375 	int ret;
376 
377 	ret = cifs_swn_send_unregister_message(swnreg);
378 	if (ret < 0)
379 		cifs_dbg(VFS, "%s: Failed to send unregister message: %d\n", __func__, ret);
380 
381 	idr_remove(&cifs_swnreg_idr, swnreg->id);
382 	kfree(swnreg->net_name);
383 	kfree(swnreg->share_name);
384 	kfree(swnreg);
385 }
386 
387 static void cifs_put_swn_reg(struct cifs_swn_reg *swnreg)
388 {
389 	mutex_lock(&cifs_swnreg_idr_mutex);
390 	kref_put(&swnreg->ref_count, cifs_swn_reg_release);
391 	mutex_unlock(&cifs_swnreg_idr_mutex);
392 }
393 
394 static int cifs_swn_resource_state_changed(struct cifs_swn_reg *swnreg, const char *name, int state)
395 {
396 	switch (state) {
397 	case CIFS_SWN_RESOURCE_STATE_UNAVAILABLE:
398 		cifs_dbg(FYI, "%s: resource name '%s' become unavailable\n", __func__, name);
399 		cifs_signal_cifsd_for_reconnect(swnreg->tcon->ses->server, true);
400 		break;
401 	case CIFS_SWN_RESOURCE_STATE_AVAILABLE:
402 		cifs_dbg(FYI, "%s: resource name '%s' become available\n", __func__, name);
403 		cifs_signal_cifsd_for_reconnect(swnreg->tcon->ses->server, true);
404 		break;
405 	case CIFS_SWN_RESOURCE_STATE_UNKNOWN:
406 		cifs_dbg(FYI, "%s: resource name '%s' changed to unknown state\n", __func__, name);
407 		break;
408 	}
409 	return 0;
410 }
411 
412 static bool cifs_sockaddr_equal(struct sockaddr_storage *addr1, struct sockaddr_storage *addr2)
413 {
414 	if (addr1->ss_family != addr2->ss_family)
415 		return false;
416 
417 	if (addr1->ss_family == AF_INET) {
418 		return (memcmp(&((const struct sockaddr_in *)addr1)->sin_addr,
419 				&((const struct sockaddr_in *)addr2)->sin_addr,
420 				sizeof(struct in_addr)) == 0);
421 	}
422 
423 	if (addr1->ss_family == AF_INET6) {
424 		return (memcmp(&((const struct sockaddr_in6 *)addr1)->sin6_addr,
425 				&((const struct sockaddr_in6 *)addr2)->sin6_addr,
426 				sizeof(struct in6_addr)) == 0);
427 	}
428 
429 	return false;
430 }
431 
432 static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
433 				   const struct sockaddr_storage *old,
434 				   struct sockaddr_storage *dst)
435 {
436 	__be16 port = cpu_to_be16(CIFS_PORT);
437 
438 	if (old->ss_family == AF_INET) {
439 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)old;
440 
441 		port = ipv4->sin_port;
442 	} else if (old->ss_family == AF_INET6) {
443 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)old;
444 
445 		port = ipv6->sin6_port;
446 	}
447 
448 	if (new->ss_family == AF_INET) {
449 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)new;
450 
451 		ipv4->sin_port = port;
452 	} else if (new->ss_family == AF_INET6) {
453 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)new;
454 
455 		ipv6->sin6_port = port;
456 	}
457 
458 	*dst = *new;
459 
460 	return 0;
461 }
462 
463 static int cifs_swn_reconnect(struct cifs_tcon *tcon, struct sockaddr_storage *addr)
464 {
465 	int ret = 0;
466 
467 	/* Store the reconnect address */
468 	cifs_server_lock(tcon->ses->server);
469 	if (cifs_sockaddr_equal(&tcon->ses->server->dstaddr, addr))
470 		goto unlock;
471 
472 	ret = cifs_swn_store_swn_addr(addr, &tcon->ses->server->dstaddr,
473 				      &tcon->ses->server->swn_dstaddr);
474 	if (ret < 0) {
475 		cifs_dbg(VFS, "%s: failed to store address: %d\n", __func__, ret);
476 		goto unlock;
477 	}
478 	tcon->ses->server->use_swn_dstaddr = true;
479 
480 	/*
481 	 * Unregister to stop receiving notifications for the old IP address.
482 	 */
483 	ret = cifs_swn_unregister(tcon);
484 	if (ret < 0) {
485 		cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
486 			 __func__, ret);
487 		goto unlock;
488 	}
489 
490 	/*
491 	 * And register to receive notifications for the new IP address now that we have
492 	 * stored the new address.
493 	 */
494 	ret = cifs_swn_register(tcon);
495 	if (ret < 0) {
496 		cifs_dbg(VFS, "%s: Failed to register for witness notifications: %d\n",
497 			 __func__, ret);
498 		goto unlock;
499 	}
500 
501 	cifs_signal_cifsd_for_reconnect(tcon->ses->server, false);
502 
503 unlock:
504 	cifs_server_unlock(tcon->ses->server);
505 
506 	return ret;
507 }
508 
509 static int cifs_swn_client_move(struct cifs_swn_reg *swnreg, struct sockaddr_storage *addr)
510 {
511 	struct sockaddr_in *ipv4 = (struct sockaddr_in *)addr;
512 	struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)addr;
513 
514 	if (addr->ss_family == AF_INET)
515 		cifs_dbg(FYI, "%s: move to %pI4\n", __func__, &ipv4->sin_addr);
516 	else if (addr->ss_family == AF_INET6)
517 		cifs_dbg(FYI, "%s: move to %pI6\n", __func__, &ipv6->sin6_addr);
518 
519 	return cifs_swn_reconnect(swnreg->tcon, addr);
520 }
521 
522 int cifs_swn_notify(struct sk_buff *skb, struct genl_info *info)
523 {
524 	struct cifs_swn_reg *swnreg;
525 	char name[256];
526 	int type;
527 
528 	if (info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]) {
529 		int swnreg_id;
530 
531 		swnreg_id = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]);
532 		mutex_lock(&cifs_swnreg_idr_mutex);
533 		swnreg = idr_find(&cifs_swnreg_idr, swnreg_id);
534 		mutex_unlock(&cifs_swnreg_idr_mutex);
535 		if (swnreg == NULL) {
536 			cifs_dbg(FYI, "%s: registration id %d not found\n", __func__, swnreg_id);
537 			return -EINVAL;
538 		}
539 	} else {
540 		cifs_dbg(FYI, "%s: missing registration id attribute\n", __func__);
541 		return -EINVAL;
542 	}
543 
544 	if (info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]) {
545 		type = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]);
546 	} else {
547 		cifs_dbg(FYI, "%s: missing notification type attribute\n", __func__);
548 		return -EINVAL;
549 	}
550 
551 	switch (type) {
552 	case CIFS_SWN_NOTIFICATION_RESOURCE_CHANGE: {
553 		int state;
554 
555 		if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME]) {
556 			nla_strscpy(name, info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME],
557 					sizeof(name));
558 		} else {
559 			cifs_dbg(FYI, "%s: missing resource name attribute\n", __func__);
560 			return -EINVAL;
561 		}
562 		if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]) {
563 			state = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]);
564 		} else {
565 			cifs_dbg(FYI, "%s: missing resource state attribute\n", __func__);
566 			return -EINVAL;
567 		}
568 		return cifs_swn_resource_state_changed(swnreg, name, state);
569 	}
570 	case CIFS_SWN_NOTIFICATION_CLIENT_MOVE: {
571 		struct sockaddr_storage addr;
572 
573 		if (info->attrs[CIFS_GENL_ATTR_SWN_IP]) {
574 			nla_memcpy(&addr, info->attrs[CIFS_GENL_ATTR_SWN_IP], sizeof(addr));
575 		} else {
576 			cifs_dbg(FYI, "%s: missing IP address attribute\n", __func__);
577 			return -EINVAL;
578 		}
579 		return cifs_swn_client_move(swnreg, &addr);
580 	}
581 	default:
582 		cifs_dbg(FYI, "%s: unknown notification type %d\n", __func__, type);
583 		break;
584 	}
585 
586 	return 0;
587 }
588 
589 int cifs_swn_register(struct cifs_tcon *tcon)
590 {
591 	struct cifs_swn_reg *swnreg;
592 	int ret;
593 
594 	swnreg = cifs_get_swn_reg(tcon);
595 	if (IS_ERR(swnreg))
596 		return PTR_ERR(swnreg);
597 
598 	ret = cifs_swn_send_register_message(swnreg);
599 	if (ret < 0) {
600 		cifs_dbg(VFS, "%s: Failed to send swn register message: %d\n", __func__, ret);
601 		/* Do not put the swnreg or return error, the echo task will retry */
602 	}
603 
604 	return 0;
605 }
606 
607 int cifs_swn_unregister(struct cifs_tcon *tcon)
608 {
609 	struct cifs_swn_reg *swnreg;
610 
611 	mutex_lock(&cifs_swnreg_idr_mutex);
612 
613 	swnreg = cifs_find_swn_reg(tcon);
614 	if (IS_ERR(swnreg)) {
615 		mutex_unlock(&cifs_swnreg_idr_mutex);
616 		return PTR_ERR(swnreg);
617 	}
618 
619 	mutex_unlock(&cifs_swnreg_idr_mutex);
620 
621 	cifs_put_swn_reg(swnreg);
622 
623 	return 0;
624 }
625 
626 void cifs_swn_dump(struct seq_file *m)
627 {
628 	struct cifs_swn_reg *swnreg;
629 	struct sockaddr_in *sa;
630 	struct sockaddr_in6 *sa6;
631 	int id;
632 
633 	seq_puts(m, "Witness registrations:");
634 
635 	mutex_lock(&cifs_swnreg_idr_mutex);
636 	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
637 		seq_printf(m, "\nId: %u Refs: %u Network name: '%s'%s Share name: '%s'%s Ip address: ",
638 				id, kref_read(&swnreg->ref_count),
639 				swnreg->net_name, swnreg->net_name_notify ? "(y)" : "(n)",
640 				swnreg->share_name, swnreg->share_name_notify ? "(y)" : "(n)");
641 		switch (swnreg->tcon->ses->server->dstaddr.ss_family) {
642 		case AF_INET:
643 			sa = (struct sockaddr_in *) &swnreg->tcon->ses->server->dstaddr;
644 			seq_printf(m, "%pI4", &sa->sin_addr.s_addr);
645 			break;
646 		case AF_INET6:
647 			sa6 = (struct sockaddr_in6 *) &swnreg->tcon->ses->server->dstaddr;
648 			seq_printf(m, "%pI6", &sa6->sin6_addr.s6_addr);
649 			if (sa6->sin6_scope_id)
650 				seq_printf(m, "%%%u", sa6->sin6_scope_id);
651 			break;
652 		default:
653 			seq_puts(m, "(unknown)");
654 		}
655 		seq_printf(m, "%s", swnreg->ip_notify ? "(y)" : "(n)");
656 	}
657 	mutex_unlock(&cifs_swnreg_idr_mutex);
658 	seq_puts(m, "\n");
659 }
660 
661 void cifs_swn_check(void)
662 {
663 	struct cifs_swn_reg *swnreg;
664 	int id;
665 	int ret;
666 
667 	mutex_lock(&cifs_swnreg_idr_mutex);
668 	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
669 		ret = cifs_swn_send_register_message(swnreg);
670 		if (ret < 0)
671 			cifs_dbg(FYI, "%s: Failed to send register message: %d\n", __func__, ret);
672 	}
673 	mutex_unlock(&cifs_swnreg_idr_mutex);
674 }
675