xref: /linux/fs/smb/client/connect.c (revision 73aea586d6c58f55799f6130e19321ff7b574c3d)
1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3  *
4  *   Copyright (C) International Business Machines  Corp., 2002,2011
5  *   Author(s): Steve French (sfrench@us.ibm.com)
6  *
7  */
8 #include <linux/fs.h>
9 #include <linux/net.h>
10 #include <linux/string.h>
11 #include <linux/sched/mm.h>
12 #include <linux/sched/signal.h>
13 #include <linux/list.h>
14 #include <linux/wait.h>
15 #include <linux/slab.h>
16 #include <linux/pagemap.h>
17 #include <linux/ctype.h>
18 #include <linux/utsname.h>
19 #include <linux/mempool.h>
20 #include <linux/delay.h>
21 #include <linux/completion.h>
22 #include <linux/kthread.h>
23 #include <linux/pagevec.h>
24 #include <linux/freezer.h>
25 #include <linux/namei.h>
26 #include <linux/uuid.h>
27 #include <linux/uaccess.h>
28 #include <asm/processor.h>
29 #include <linux/inet.h>
30 #include <linux/module.h>
31 #include <keys/user-type.h>
32 #include <net/ipv6.h>
33 #include <linux/parser.h>
34 #include <linux/bvec.h>
35 #include "cifspdu.h"
36 #include "cifsglob.h"
37 #include "cifsproto.h"
38 #include "cifs_unicode.h"
39 #include "cifs_debug.h"
40 #include "cifs_fs_sb.h"
41 #include "ntlmssp.h"
42 #include "nterr.h"
43 #include "rfc1002pdu.h"
44 #include "fscache.h"
45 #include "smb2proto.h"
46 #include "smbdirect.h"
47 #include "dns_resolve.h"
48 #ifdef CONFIG_CIFS_DFS_UPCALL
49 #include "dfs.h"
50 #include "dfs_cache.h"
51 #endif
52 #include "fs_context.h"
53 #include "cifs_swn.h"
54 
55 extern mempool_t *cifs_req_poolp;
56 extern bool disable_legacy_dialects;
57 
58 /* FIXME: should these be tunable? */
59 #define TLINK_ERROR_EXPIRE	(1 * HZ)
60 #define TLINK_IDLE_EXPIRE	(600 * HZ)
61 
62 /* Drop the connection to not overload the server */
63 #define MAX_STATUS_IO_TIMEOUT   5
64 
65 static int ip_connect(struct TCP_Server_Info *server);
66 static int generic_ip_connect(struct TCP_Server_Info *server);
67 static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
68 static void cifs_prune_tlinks(struct work_struct *work);
69 
70 /*
71  * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
72  * get their ip addresses changed at some point.
73  *
74  * This should be called with server->srv_mutex held.
75  */
76 static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
77 {
78 	int rc;
79 	int len;
80 	char *unc;
81 	struct sockaddr_storage ss;
82 
83 	if (!server->hostname)
84 		return -EINVAL;
85 
86 	/* if server hostname isn't populated, there's nothing to do here */
87 	if (server->hostname[0] == '\0')
88 		return 0;
89 
90 	len = strlen(server->hostname) + 3;
91 
92 	unc = kmalloc(len, GFP_KERNEL);
93 	if (!unc) {
94 		cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
95 		return -ENOMEM;
96 	}
97 	scnprintf(unc, len, "\\\\%s", server->hostname);
98 
99 	spin_lock(&server->srv_lock);
100 	ss = server->dstaddr;
101 	spin_unlock(&server->srv_lock);
102 
103 	rc = dns_resolve_server_name_to_ip(unc, (struct sockaddr *)&ss, NULL);
104 	kfree(unc);
105 
106 	if (rc < 0) {
107 		cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
108 			 __func__, server->hostname, rc);
109 	} else {
110 		spin_lock(&server->srv_lock);
111 		memcpy(&server->dstaddr, &ss, sizeof(server->dstaddr));
112 		spin_unlock(&server->srv_lock);
113 		rc = 0;
114 	}
115 
116 	return rc;
117 }
118 
119 static void smb2_query_server_interfaces(struct work_struct *work)
120 {
121 	int rc;
122 	int xid;
123 	struct cifs_tcon *tcon = container_of(work,
124 					struct cifs_tcon,
125 					query_interfaces.work);
126 
127 	/*
128 	 * query server network interfaces, in case they change
129 	 */
130 	xid = get_xid();
131 	rc = SMB3_request_interfaces(xid, tcon, false);
132 	free_xid(xid);
133 
134 	if (rc) {
135 		if (rc == -EOPNOTSUPP)
136 			return;
137 
138 		cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
139 				__func__, rc);
140 	}
141 
142 	queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
143 			   (SMB_INTERFACE_POLL_INTERVAL * HZ));
144 }
145 
146 /*
147  * Update the tcpStatus for the server.
148  * This is used to signal the cifsd thread to call cifs_reconnect
149  * ONLY cifsd thread should call cifs_reconnect. For any other
150  * thread, use this function
151  *
152  * @server: the tcp ses for which reconnect is needed
153  * @all_channels: if this needs to be done for all channels
154  */
155 void
156 cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
157 				bool all_channels)
158 {
159 	struct TCP_Server_Info *pserver;
160 	struct cifs_ses *ses;
161 	int i;
162 
163 	/* If server is a channel, select the primary channel */
164 	pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
165 
166 	/* if we need to signal just this channel */
167 	if (!all_channels) {
168 		spin_lock(&server->srv_lock);
169 		if (server->tcpStatus != CifsExiting)
170 			server->tcpStatus = CifsNeedReconnect;
171 		spin_unlock(&server->srv_lock);
172 		return;
173 	}
174 
175 	spin_lock(&cifs_tcp_ses_lock);
176 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
177 		spin_lock(&ses->chan_lock);
178 		for (i = 0; i < ses->chan_count; i++) {
179 			if (!ses->chans[i].server)
180 				continue;
181 
182 			spin_lock(&ses->chans[i].server->srv_lock);
183 			if (ses->chans[i].server->tcpStatus != CifsExiting)
184 				ses->chans[i].server->tcpStatus = CifsNeedReconnect;
185 			spin_unlock(&ses->chans[i].server->srv_lock);
186 		}
187 		spin_unlock(&ses->chan_lock);
188 	}
189 	spin_unlock(&cifs_tcp_ses_lock);
190 }
191 
192 /*
193  * Mark all sessions and tcons for reconnect.
194  * IMPORTANT: make sure that this gets called only from
195  * cifsd thread. For any other thread, use
196  * cifs_signal_cifsd_for_reconnect
197  *
198  * @server: the tcp ses for which reconnect is needed
199  * @server needs to be previously set to CifsNeedReconnect.
200  * @mark_smb_session: whether even sessions need to be marked
201  */
202 void
203 cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
204 				      bool mark_smb_session)
205 {
206 	struct TCP_Server_Info *pserver;
207 	struct cifs_ses *ses, *nses;
208 	struct cifs_tcon *tcon;
209 
210 	/*
211 	 * before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they
212 	 * are not used until reconnected.
213 	 */
214 	cifs_dbg(FYI, "%s: marking necessary sessions and tcons for reconnect\n", __func__);
215 
216 	/* If server is a channel, select the primary channel */
217 	pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
218 
219 
220 	spin_lock(&cifs_tcp_ses_lock);
221 	list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
222 		/*
223 		 * if channel has been marked for termination, nothing to do
224 		 * for the channel. in fact, we cannot find the channel for the
225 		 * server. So safe to exit here
226 		 */
227 		if (server->terminate)
228 			break;
229 
230 		/* check if iface is still active */
231 		if (!cifs_chan_is_iface_active(ses, server))
232 			cifs_chan_update_iface(ses, server);
233 
234 		spin_lock(&ses->chan_lock);
235 		if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server)) {
236 			spin_unlock(&ses->chan_lock);
237 			continue;
238 		}
239 
240 		if (mark_smb_session)
241 			CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses);
242 		else
243 			cifs_chan_set_need_reconnect(ses, server);
244 
245 		cifs_dbg(FYI, "%s: channel connect bitmap: 0x%lx\n",
246 			 __func__, ses->chans_need_reconnect);
247 
248 		/* If all channels need reconnect, then tcon needs reconnect */
249 		if (!mark_smb_session && !CIFS_ALL_CHANS_NEED_RECONNECT(ses)) {
250 			spin_unlock(&ses->chan_lock);
251 			continue;
252 		}
253 		spin_unlock(&ses->chan_lock);
254 
255 		spin_lock(&ses->ses_lock);
256 		ses->ses_status = SES_NEED_RECON;
257 		spin_unlock(&ses->ses_lock);
258 
259 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
260 			tcon->need_reconnect = true;
261 			spin_lock(&tcon->tc_lock);
262 			tcon->status = TID_NEED_RECON;
263 			spin_unlock(&tcon->tc_lock);
264 
265 			cancel_delayed_work(&tcon->query_interfaces);
266 		}
267 		if (ses->tcon_ipc) {
268 			ses->tcon_ipc->need_reconnect = true;
269 			spin_lock(&ses->tcon_ipc->tc_lock);
270 			ses->tcon_ipc->status = TID_NEED_RECON;
271 			spin_unlock(&ses->tcon_ipc->tc_lock);
272 		}
273 	}
274 	spin_unlock(&cifs_tcp_ses_lock);
275 }
276 
277 static void
278 cifs_abort_connection(struct TCP_Server_Info *server)
279 {
280 	struct mid_q_entry *mid, *nmid;
281 	struct list_head retry_list;
282 
283 	server->maxBuf = 0;
284 	server->max_read = 0;
285 
286 	/* do not want to be sending data on a socket we are freeing */
287 	cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
288 	cifs_server_lock(server);
289 	if (server->ssocket) {
290 		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
291 			 server->ssocket->flags);
292 		kernel_sock_shutdown(server->ssocket, SHUT_WR);
293 		cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n", server->ssocket->state,
294 			 server->ssocket->flags);
295 		sock_release(server->ssocket);
296 		server->ssocket = NULL;
297 	}
298 	server->sequence_number = 0;
299 	server->session_estab = false;
300 	kfree_sensitive(server->session_key.response);
301 	server->session_key.response = NULL;
302 	server->session_key.len = 0;
303 	server->lstrp = jiffies;
304 
305 	/* mark submitted MIDs for retry and issue callback */
306 	INIT_LIST_HEAD(&retry_list);
307 	cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
308 	spin_lock(&server->mid_lock);
309 	list_for_each_entry_safe(mid, nmid, &server->pending_mid_q, qhead) {
310 		kref_get(&mid->refcount);
311 		if (mid->mid_state == MID_REQUEST_SUBMITTED)
312 			mid->mid_state = MID_RETRY_NEEDED;
313 		list_move(&mid->qhead, &retry_list);
314 		mid->mid_flags |= MID_DELETED;
315 	}
316 	spin_unlock(&server->mid_lock);
317 	cifs_server_unlock(server);
318 
319 	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
320 	list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
321 		list_del_init(&mid->qhead);
322 		mid->callback(mid);
323 		release_mid(mid);
324 	}
325 
326 	if (cifs_rdma_enabled(server)) {
327 		cifs_server_lock(server);
328 		smbd_destroy(server);
329 		cifs_server_unlock(server);
330 	}
331 }
332 
333 static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
334 {
335 	spin_lock(&server->srv_lock);
336 	server->nr_targets = num_targets;
337 	if (server->tcpStatus == CifsExiting) {
338 		/* the demux thread will exit normally next time through the loop */
339 		spin_unlock(&server->srv_lock);
340 		wake_up(&server->response_q);
341 		return false;
342 	}
343 
344 	cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
345 	trace_smb3_reconnect(server->CurrentMid, server->conn_id,
346 			     server->hostname);
347 	server->tcpStatus = CifsNeedReconnect;
348 
349 	spin_unlock(&server->srv_lock);
350 	return true;
351 }
352 
353 /*
354  * cifs tcp session reconnection
355  *
356  * mark tcp session as reconnecting so temporarily locked
357  * mark all smb sessions as reconnecting for tcp session
358  * reconnect tcp session
359  * wake up waiters on reconnection? - (not needed currently)
360  *
361  * if mark_smb_session is passed as true, unconditionally mark
362  * the smb session (and tcon) for reconnect as well. This value
363  * doesn't really matter for non-multichannel scenario.
364  *
365  */
366 static int __cifs_reconnect(struct TCP_Server_Info *server,
367 			    bool mark_smb_session)
368 {
369 	int rc = 0;
370 
371 	if (!cifs_tcp_ses_needs_reconnect(server, 1))
372 		return 0;
373 
374 	cifs_mark_tcp_ses_conns_for_reconnect(server, mark_smb_session);
375 
376 	cifs_abort_connection(server);
377 
378 	do {
379 		try_to_freeze();
380 		cifs_server_lock(server);
381 
382 		if (!cifs_swn_set_server_dstaddr(server)) {
383 			/* resolve the hostname again to make sure that IP address is up-to-date */
384 			rc = reconn_set_ipaddr_from_hostname(server);
385 			cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
386 		}
387 
388 		if (cifs_rdma_enabled(server))
389 			rc = smbd_reconnect(server);
390 		else
391 			rc = generic_ip_connect(server);
392 		if (rc) {
393 			cifs_server_unlock(server);
394 			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
395 			msleep(3000);
396 		} else {
397 			atomic_inc(&tcpSesReconnectCount);
398 			set_credits(server, 1);
399 			spin_lock(&server->srv_lock);
400 			if (server->tcpStatus != CifsExiting)
401 				server->tcpStatus = CifsNeedNegotiate;
402 			spin_unlock(&server->srv_lock);
403 			cifs_swn_reset_server_dstaddr(server);
404 			cifs_server_unlock(server);
405 
406 			/* increase ref count which reconnect work will drop */
407 			spin_lock(&cifs_tcp_ses_lock);
408 			server->srv_count++;
409 			spin_unlock(&cifs_tcp_ses_lock);
410 			if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))
411 				cifs_put_tcp_session(server, false);
412 		}
413 	} while (server->tcpStatus == CifsNeedReconnect);
414 
415 	spin_lock(&server->srv_lock);
416 	if (server->tcpStatus == CifsNeedNegotiate)
417 		mod_delayed_work(cifsiod_wq, &server->echo, 0);
418 	spin_unlock(&server->srv_lock);
419 
420 	wake_up(&server->response_q);
421 	return rc;
422 }
423 
424 #ifdef CONFIG_CIFS_DFS_UPCALL
425 static int __reconnect_target_unlocked(struct TCP_Server_Info *server, const char *target)
426 {
427 	int rc;
428 	char *hostname;
429 
430 	if (!cifs_swn_set_server_dstaddr(server)) {
431 		if (server->hostname != target) {
432 			hostname = extract_hostname(target);
433 			if (!IS_ERR(hostname)) {
434 				spin_lock(&server->srv_lock);
435 				kfree(server->hostname);
436 				server->hostname = hostname;
437 				spin_unlock(&server->srv_lock);
438 			} else {
439 				cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
440 					 __func__, PTR_ERR(hostname));
441 				cifs_dbg(FYI, "%s: default to last target server: %s\n", __func__,
442 					 server->hostname);
443 			}
444 		}
445 		/* resolve the hostname again to make sure that IP address is up-to-date. */
446 		rc = reconn_set_ipaddr_from_hostname(server);
447 		cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
448 	}
449 	/* Reconnect the socket */
450 	if (cifs_rdma_enabled(server))
451 		rc = smbd_reconnect(server);
452 	else
453 		rc = generic_ip_connect(server);
454 
455 	return rc;
456 }
457 
458 static int reconnect_target_unlocked(struct TCP_Server_Info *server, struct dfs_cache_tgt_list *tl,
459 				     struct dfs_cache_tgt_iterator **target_hint)
460 {
461 	int rc;
462 	struct dfs_cache_tgt_iterator *tit;
463 
464 	*target_hint = NULL;
465 
466 	/* If dfs target list is empty, then reconnect to last server */
467 	tit = dfs_cache_get_tgt_iterator(tl);
468 	if (!tit)
469 		return __reconnect_target_unlocked(server, server->hostname);
470 
471 	/* Otherwise, try every dfs target in @tl */
472 	for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
473 		rc = __reconnect_target_unlocked(server, dfs_cache_get_tgt_name(tit));
474 		if (!rc) {
475 			*target_hint = tit;
476 			break;
477 		}
478 	}
479 	return rc;
480 }
481 
482 static int reconnect_dfs_server(struct TCP_Server_Info *server)
483 {
484 	struct dfs_cache_tgt_iterator *target_hint = NULL;
485 	DFS_CACHE_TGT_LIST(tl);
486 	int num_targets = 0;
487 	int rc = 0;
488 
489 	/*
490 	 * Determine the number of dfs targets the referral path in @cifs_sb resolves to.
491 	 *
492 	 * smb2_reconnect() needs to know how long it should wait based upon the number of dfs
493 	 * targets (server->nr_targets).  It's also possible that the cached referral was cleared
494 	 * through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
495 	 * refreshing the referral, so, in this case, default it to 1.
496 	 */
497 	mutex_lock(&server->refpath_lock);
498 	if (!dfs_cache_noreq_find(server->leaf_fullpath + 1, NULL, &tl))
499 		num_targets = dfs_cache_get_nr_tgts(&tl);
500 	mutex_unlock(&server->refpath_lock);
501 	if (!num_targets)
502 		num_targets = 1;
503 
504 	if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
505 		return 0;
506 
507 	/*
508 	 * Unconditionally mark all sessions & tcons for reconnect as we might be connecting to a
509 	 * different server or share during failover.  It could be improved by adding some logic to
510 	 * only do that in case it connects to a different server or share, though.
511 	 */
512 	cifs_mark_tcp_ses_conns_for_reconnect(server, true);
513 
514 	cifs_abort_connection(server);
515 
516 	do {
517 		try_to_freeze();
518 		cifs_server_lock(server);
519 
520 		rc = reconnect_target_unlocked(server, &tl, &target_hint);
521 		if (rc) {
522 			/* Failed to reconnect socket */
523 			cifs_server_unlock(server);
524 			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
525 			msleep(3000);
526 			continue;
527 		}
528 		/*
529 		 * Socket was created.  Update tcp session status to CifsNeedNegotiate so that a
530 		 * process waiting for reconnect will know it needs to re-establish session and tcon
531 		 * through the reconnected target server.
532 		 */
533 		atomic_inc(&tcpSesReconnectCount);
534 		set_credits(server, 1);
535 		spin_lock(&server->srv_lock);
536 		if (server->tcpStatus != CifsExiting)
537 			server->tcpStatus = CifsNeedNegotiate;
538 		spin_unlock(&server->srv_lock);
539 		cifs_swn_reset_server_dstaddr(server);
540 		cifs_server_unlock(server);
541 
542 		/* increase ref count which reconnect work will drop */
543 		spin_lock(&cifs_tcp_ses_lock);
544 		server->srv_count++;
545 		spin_unlock(&cifs_tcp_ses_lock);
546 		if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))
547 			cifs_put_tcp_session(server, false);
548 	} while (server->tcpStatus == CifsNeedReconnect);
549 
550 	mutex_lock(&server->refpath_lock);
551 	dfs_cache_noreq_update_tgthint(server->leaf_fullpath + 1, target_hint);
552 	mutex_unlock(&server->refpath_lock);
553 	dfs_cache_free_tgts(&tl);
554 
555 	/* Need to set up echo worker again once connection has been established */
556 	spin_lock(&server->srv_lock);
557 	if (server->tcpStatus == CifsNeedNegotiate)
558 		mod_delayed_work(cifsiod_wq, &server->echo, 0);
559 	spin_unlock(&server->srv_lock);
560 
561 	wake_up(&server->response_q);
562 	return rc;
563 }
564 
565 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
566 {
567 	mutex_lock(&server->refpath_lock);
568 	if (!server->leaf_fullpath) {
569 		mutex_unlock(&server->refpath_lock);
570 		return __cifs_reconnect(server, mark_smb_session);
571 	}
572 	mutex_unlock(&server->refpath_lock);
573 
574 	return reconnect_dfs_server(server);
575 }
576 #else
577 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
578 {
579 	return __cifs_reconnect(server, mark_smb_session);
580 }
581 #endif
582 
583 static void
584 cifs_echo_request(struct work_struct *work)
585 {
586 	int rc;
587 	struct TCP_Server_Info *server = container_of(work,
588 					struct TCP_Server_Info, echo.work);
589 
590 	/*
591 	 * We cannot send an echo if it is disabled.
592 	 * Also, no need to ping if we got a response recently.
593 	 */
594 
595 	if (server->tcpStatus == CifsNeedReconnect ||
596 	    server->tcpStatus == CifsExiting ||
597 	    server->tcpStatus == CifsNew ||
598 	    (server->ops->can_echo && !server->ops->can_echo(server)) ||
599 	    time_before(jiffies, server->lstrp + server->echo_interval - HZ))
600 		goto requeue_echo;
601 
602 	rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
603 	cifs_server_dbg(FYI, "send echo request: rc = %d\n", rc);
604 
605 	/* Check witness registrations */
606 	cifs_swn_check();
607 
608 requeue_echo:
609 	queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
610 }
611 
612 static bool
613 allocate_buffers(struct TCP_Server_Info *server)
614 {
615 	if (!server->bigbuf) {
616 		server->bigbuf = (char *)cifs_buf_get();
617 		if (!server->bigbuf) {
618 			cifs_server_dbg(VFS, "No memory for large SMB response\n");
619 			msleep(3000);
620 			/* retry will check if exiting */
621 			return false;
622 		}
623 	} else if (server->large_buf) {
624 		/* we are reusing a dirty large buf, clear its start */
625 		memset(server->bigbuf, 0, HEADER_SIZE(server));
626 	}
627 
628 	if (!server->smallbuf) {
629 		server->smallbuf = (char *)cifs_small_buf_get();
630 		if (!server->smallbuf) {
631 			cifs_server_dbg(VFS, "No memory for SMB response\n");
632 			msleep(1000);
633 			/* retry will check if exiting */
634 			return false;
635 		}
636 		/* beginning of smb buffer is cleared in our buf_get */
637 	} else {
638 		/* if existing small buf clear beginning */
639 		memset(server->smallbuf, 0, HEADER_SIZE(server));
640 	}
641 
642 	return true;
643 }
644 
645 static bool
646 server_unresponsive(struct TCP_Server_Info *server)
647 {
648 	/*
649 	 * We need to wait 3 echo intervals to make sure we handle such
650 	 * situations right:
651 	 * 1s  client sends a normal SMB request
652 	 * 2s  client gets a response
653 	 * 30s echo workqueue job pops, and decides we got a response recently
654 	 *     and don't need to send another
655 	 * ...
656 	 * 65s kernel_recvmsg times out, and we see that we haven't gotten
657 	 *     a response in >60s.
658 	 */
659 	spin_lock(&server->srv_lock);
660 	if ((server->tcpStatus == CifsGood ||
661 	    server->tcpStatus == CifsNeedNegotiate) &&
662 	    (!server->ops->can_echo || server->ops->can_echo(server)) &&
663 	    time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
664 		spin_unlock(&server->srv_lock);
665 		cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
666 			 (3 * server->echo_interval) / HZ);
667 		cifs_reconnect(server, false);
668 		return true;
669 	}
670 	spin_unlock(&server->srv_lock);
671 
672 	return false;
673 }
674 
675 static inline bool
676 zero_credits(struct TCP_Server_Info *server)
677 {
678 	int val;
679 
680 	spin_lock(&server->req_lock);
681 	val = server->credits + server->echo_credits + server->oplock_credits;
682 	if (server->in_flight == 0 && val == 0) {
683 		spin_unlock(&server->req_lock);
684 		return true;
685 	}
686 	spin_unlock(&server->req_lock);
687 	return false;
688 }
689 
690 static int
691 cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
692 {
693 	int length = 0;
694 	int total_read;
695 
696 	for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
697 		try_to_freeze();
698 
699 		/* reconnect if no credits and no requests in flight */
700 		if (zero_credits(server)) {
701 			cifs_reconnect(server, false);
702 			return -ECONNABORTED;
703 		}
704 
705 		if (server_unresponsive(server))
706 			return -ECONNABORTED;
707 		if (cifs_rdma_enabled(server) && server->smbd_conn)
708 			length = smbd_recv(server->smbd_conn, smb_msg);
709 		else
710 			length = sock_recvmsg(server->ssocket, smb_msg, 0);
711 
712 		spin_lock(&server->srv_lock);
713 		if (server->tcpStatus == CifsExiting) {
714 			spin_unlock(&server->srv_lock);
715 			return -ESHUTDOWN;
716 		}
717 
718 		if (server->tcpStatus == CifsNeedReconnect) {
719 			spin_unlock(&server->srv_lock);
720 			cifs_reconnect(server, false);
721 			return -ECONNABORTED;
722 		}
723 		spin_unlock(&server->srv_lock);
724 
725 		if (length == -ERESTARTSYS ||
726 		    length == -EAGAIN ||
727 		    length == -EINTR) {
728 			/*
729 			 * Minimum sleep to prevent looping, allowing socket
730 			 * to clear and app threads to set tcpStatus
731 			 * CifsNeedReconnect if server hung.
732 			 */
733 			usleep_range(1000, 2000);
734 			length = 0;
735 			continue;
736 		}
737 
738 		if (length <= 0) {
739 			cifs_dbg(FYI, "Received no data or error: %d\n", length);
740 			cifs_reconnect(server, false);
741 			return -ECONNABORTED;
742 		}
743 	}
744 	return total_read;
745 }
746 
747 int
748 cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
749 		      unsigned int to_read)
750 {
751 	struct msghdr smb_msg = {};
752 	struct kvec iov = {.iov_base = buf, .iov_len = to_read};
753 	iov_iter_kvec(&smb_msg.msg_iter, ITER_DEST, &iov, 1, to_read);
754 
755 	return cifs_readv_from_socket(server, &smb_msg);
756 }
757 
758 ssize_t
759 cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
760 {
761 	struct msghdr smb_msg = {};
762 
763 	/*
764 	 *  iov_iter_discard already sets smb_msg.type and count and iov_offset
765 	 *  and cifs_readv_from_socket sets msg_control and msg_controllen
766 	 *  so little to initialize in struct msghdr
767 	 */
768 	iov_iter_discard(&smb_msg.msg_iter, ITER_DEST, to_read);
769 
770 	return cifs_readv_from_socket(server, &smb_msg);
771 }
772 
773 int
774 cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
775 	unsigned int page_offset, unsigned int to_read)
776 {
777 	struct msghdr smb_msg = {};
778 	struct bio_vec bv;
779 
780 	bvec_set_page(&bv, page, to_read, page_offset);
781 	iov_iter_bvec(&smb_msg.msg_iter, ITER_DEST, &bv, 1, to_read);
782 	return cifs_readv_from_socket(server, &smb_msg);
783 }
784 
785 int
786 cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter,
787 			   unsigned int to_read)
788 {
789 	struct msghdr smb_msg = { .msg_iter = *iter };
790 	int ret;
791 
792 	iov_iter_truncate(&smb_msg.msg_iter, to_read);
793 	ret = cifs_readv_from_socket(server, &smb_msg);
794 	if (ret > 0)
795 		iov_iter_advance(iter, ret);
796 	return ret;
797 }
798 
799 static bool
800 is_smb_response(struct TCP_Server_Info *server, unsigned char type)
801 {
802 	/*
803 	 * The first byte big endian of the length field,
804 	 * is actually not part of the length but the type
805 	 * with the most common, zero, as regular data.
806 	 */
807 	switch (type) {
808 	case RFC1002_SESSION_MESSAGE:
809 		/* Regular SMB response */
810 		return true;
811 	case RFC1002_SESSION_KEEP_ALIVE:
812 		cifs_dbg(FYI, "RFC 1002 session keep alive\n");
813 		break;
814 	case RFC1002_POSITIVE_SESSION_RESPONSE:
815 		cifs_dbg(FYI, "RFC 1002 positive session response\n");
816 		break;
817 	case RFC1002_NEGATIVE_SESSION_RESPONSE:
818 		/*
819 		 * We get this from Windows 98 instead of an error on
820 		 * SMB negprot response.
821 		 */
822 		cifs_dbg(FYI, "RFC 1002 negative session response\n");
823 		/* give server a second to clean up */
824 		msleep(1000);
825 		/*
826 		 * Always try 445 first on reconnect since we get NACK
827 		 * on some if we ever connected to port 139 (the NACK
828 		 * is since we do not begin with RFC1001 session
829 		 * initialize frame).
830 		 */
831 		cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
832 		cifs_reconnect(server, true);
833 		break;
834 	default:
835 		cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
836 		cifs_reconnect(server, true);
837 	}
838 
839 	return false;
840 }
841 
842 void
843 dequeue_mid(struct mid_q_entry *mid, bool malformed)
844 {
845 #ifdef CONFIG_CIFS_STATS2
846 	mid->when_received = jiffies;
847 #endif
848 	spin_lock(&mid->server->mid_lock);
849 	if (!malformed)
850 		mid->mid_state = MID_RESPONSE_RECEIVED;
851 	else
852 		mid->mid_state = MID_RESPONSE_MALFORMED;
853 	/*
854 	 * Trying to handle/dequeue a mid after the send_recv()
855 	 * function has finished processing it is a bug.
856 	 */
857 	if (mid->mid_flags & MID_DELETED) {
858 		spin_unlock(&mid->server->mid_lock);
859 		pr_warn_once("trying to dequeue a deleted mid\n");
860 	} else {
861 		list_del_init(&mid->qhead);
862 		mid->mid_flags |= MID_DELETED;
863 		spin_unlock(&mid->server->mid_lock);
864 	}
865 }
866 
867 static unsigned int
868 smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
869 {
870 	struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
871 
872 	/*
873 	 * SMB1 does not use credits.
874 	 */
875 	if (is_smb1(server))
876 		return 0;
877 
878 	return le16_to_cpu(shdr->CreditRequest);
879 }
880 
881 static void
882 handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
883 	   char *buf, int malformed)
884 {
885 	if (server->ops->check_trans2 &&
886 	    server->ops->check_trans2(mid, server, buf, malformed))
887 		return;
888 	mid->credits_received = smb2_get_credits_from_hdr(buf, server);
889 	mid->resp_buf = buf;
890 	mid->large_buf = server->large_buf;
891 	/* Was previous buf put in mpx struct for multi-rsp? */
892 	if (!mid->multiRsp) {
893 		/* smb buffer will be freed by user thread */
894 		if (server->large_buf)
895 			server->bigbuf = NULL;
896 		else
897 			server->smallbuf = NULL;
898 	}
899 	dequeue_mid(mid, malformed);
900 }
901 
902 int
903 cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required)
904 {
905 	bool srv_sign_required = server->sec_mode & server->vals->signing_required;
906 	bool srv_sign_enabled = server->sec_mode & server->vals->signing_enabled;
907 	bool mnt_sign_enabled;
908 
909 	/*
910 	 * Is signing required by mnt options? If not then check
911 	 * global_secflags to see if it is there.
912 	 */
913 	if (!mnt_sign_required)
914 		mnt_sign_required = ((global_secflags & CIFSSEC_MUST_SIGN) ==
915 						CIFSSEC_MUST_SIGN);
916 
917 	/*
918 	 * If signing is required then it's automatically enabled too,
919 	 * otherwise, check to see if the secflags allow it.
920 	 */
921 	mnt_sign_enabled = mnt_sign_required ? mnt_sign_required :
922 				(global_secflags & CIFSSEC_MAY_SIGN);
923 
924 	/* If server requires signing, does client allow it? */
925 	if (srv_sign_required) {
926 		if (!mnt_sign_enabled) {
927 			cifs_dbg(VFS, "Server requires signing, but it's disabled in SecurityFlags!\n");
928 			return -EOPNOTSUPP;
929 		}
930 		server->sign = true;
931 	}
932 
933 	/* If client requires signing, does server allow it? */
934 	if (mnt_sign_required) {
935 		if (!srv_sign_enabled) {
936 			cifs_dbg(VFS, "Server does not support signing!\n");
937 			return -EOPNOTSUPP;
938 		}
939 		server->sign = true;
940 	}
941 
942 	if (cifs_rdma_enabled(server) && server->sign)
943 		cifs_dbg(VFS, "Signing is enabled, and RDMA read/write will be disabled\n");
944 
945 	return 0;
946 }
947 
948 static noinline_for_stack void
949 clean_demultiplex_info(struct TCP_Server_Info *server)
950 {
951 	int length;
952 
953 	/* take it off the list, if it's not already */
954 	spin_lock(&server->srv_lock);
955 	list_del_init(&server->tcp_ses_list);
956 	spin_unlock(&server->srv_lock);
957 
958 	cancel_delayed_work_sync(&server->echo);
959 
960 	spin_lock(&server->srv_lock);
961 	server->tcpStatus = CifsExiting;
962 	spin_unlock(&server->srv_lock);
963 	wake_up_all(&server->response_q);
964 
965 	/* check if we have blocked requests that need to free */
966 	spin_lock(&server->req_lock);
967 	if (server->credits <= 0)
968 		server->credits = 1;
969 	spin_unlock(&server->req_lock);
970 	/*
971 	 * Although there should not be any requests blocked on this queue it
972 	 * can not hurt to be paranoid and try to wake up requests that may
973 	 * haven been blocked when more than 50 at time were on the wire to the
974 	 * same server - they now will see the session is in exit state and get
975 	 * out of SendReceive.
976 	 */
977 	wake_up_all(&server->request_q);
978 	/* give those requests time to exit */
979 	msleep(125);
980 	if (cifs_rdma_enabled(server))
981 		smbd_destroy(server);
982 	if (server->ssocket) {
983 		sock_release(server->ssocket);
984 		server->ssocket = NULL;
985 	}
986 
987 	if (!list_empty(&server->pending_mid_q)) {
988 		struct list_head dispose_list;
989 		struct mid_q_entry *mid_entry;
990 		struct list_head *tmp, *tmp2;
991 
992 		INIT_LIST_HEAD(&dispose_list);
993 		spin_lock(&server->mid_lock);
994 		list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
995 			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
996 			cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
997 			kref_get(&mid_entry->refcount);
998 			mid_entry->mid_state = MID_SHUTDOWN;
999 			list_move(&mid_entry->qhead, &dispose_list);
1000 			mid_entry->mid_flags |= MID_DELETED;
1001 		}
1002 		spin_unlock(&server->mid_lock);
1003 
1004 		/* now walk dispose list and issue callbacks */
1005 		list_for_each_safe(tmp, tmp2, &dispose_list) {
1006 			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
1007 			cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
1008 			list_del_init(&mid_entry->qhead);
1009 			mid_entry->callback(mid_entry);
1010 			release_mid(mid_entry);
1011 		}
1012 		/* 1/8th of sec is more than enough time for them to exit */
1013 		msleep(125);
1014 	}
1015 
1016 	if (!list_empty(&server->pending_mid_q)) {
1017 		/*
1018 		 * mpx threads have not exited yet give them at least the smb
1019 		 * send timeout time for long ops.
1020 		 *
1021 		 * Due to delays on oplock break requests, we need to wait at
1022 		 * least 45 seconds before giving up on a request getting a
1023 		 * response and going ahead and killing cifsd.
1024 		 */
1025 		cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
1026 		msleep(46000);
1027 		/*
1028 		 * If threads still have not exited they are probably never
1029 		 * coming home not much else we can do but free the memory.
1030 		 */
1031 	}
1032 
1033 	kfree(server->leaf_fullpath);
1034 	kfree(server);
1035 
1036 	length = atomic_dec_return(&tcpSesAllocCount);
1037 	if (length > 0)
1038 		mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
1039 }
1040 
1041 static int
1042 standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
1043 {
1044 	int length;
1045 	char *buf = server->smallbuf;
1046 	unsigned int pdu_length = server->pdu_size;
1047 
1048 	/* make sure this will fit in a large buffer */
1049 	if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
1050 	    HEADER_PREAMBLE_SIZE(server)) {
1051 		cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
1052 		cifs_reconnect(server, true);
1053 		return -ECONNABORTED;
1054 	}
1055 
1056 	/* switch to large buffer if too big for a small one */
1057 	if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
1058 		server->large_buf = true;
1059 		memcpy(server->bigbuf, buf, server->total_read);
1060 		buf = server->bigbuf;
1061 	}
1062 
1063 	/* now read the rest */
1064 	length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
1065 				       pdu_length - MID_HEADER_SIZE(server));
1066 
1067 	if (length < 0)
1068 		return length;
1069 	server->total_read += length;
1070 
1071 	dump_smb(buf, server->total_read);
1072 
1073 	return cifs_handle_standard(server, mid);
1074 }
1075 
1076 int
1077 cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
1078 {
1079 	char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
1080 	int rc;
1081 
1082 	/*
1083 	 * We know that we received enough to get to the MID as we
1084 	 * checked the pdu_length earlier. Now check to see
1085 	 * if the rest of the header is OK.
1086 	 *
1087 	 * 48 bytes is enough to display the header and a little bit
1088 	 * into the payload for debugging purposes.
1089 	 */
1090 	rc = server->ops->check_message(buf, server->total_read, server);
1091 	if (rc)
1092 		cifs_dump_mem("Bad SMB: ", buf,
1093 			min_t(unsigned int, server->total_read, 48));
1094 
1095 	if (server->ops->is_session_expired &&
1096 	    server->ops->is_session_expired(buf)) {
1097 		cifs_reconnect(server, true);
1098 		return -1;
1099 	}
1100 
1101 	if (server->ops->is_status_pending &&
1102 	    server->ops->is_status_pending(buf, server))
1103 		return -1;
1104 
1105 	if (!mid)
1106 		return rc;
1107 
1108 	handle_mid(mid, server, buf, rc);
1109 	return 0;
1110 }
1111 
1112 static void
1113 smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
1114 {
1115 	struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
1116 	int scredits, in_flight;
1117 
1118 	/*
1119 	 * SMB1 does not use credits.
1120 	 */
1121 	if (is_smb1(server))
1122 		return;
1123 
1124 	if (shdr->CreditRequest) {
1125 		spin_lock(&server->req_lock);
1126 		server->credits += le16_to_cpu(shdr->CreditRequest);
1127 		scredits = server->credits;
1128 		in_flight = server->in_flight;
1129 		spin_unlock(&server->req_lock);
1130 		wake_up(&server->request_q);
1131 
1132 		trace_smb3_hdr_credits(server->CurrentMid,
1133 				server->conn_id, server->hostname, scredits,
1134 				le16_to_cpu(shdr->CreditRequest), in_flight);
1135 		cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
1136 				__func__, le16_to_cpu(shdr->CreditRequest),
1137 				scredits);
1138 	}
1139 }
1140 
1141 
1142 static int
1143 cifs_demultiplex_thread(void *p)
1144 {
1145 	int i, num_mids, length;
1146 	struct TCP_Server_Info *server = p;
1147 	unsigned int pdu_length;
1148 	unsigned int next_offset;
1149 	char *buf = NULL;
1150 	struct task_struct *task_to_wake = NULL;
1151 	struct mid_q_entry *mids[MAX_COMPOUND];
1152 	char *bufs[MAX_COMPOUND];
1153 	unsigned int noreclaim_flag, num_io_timeout = 0;
1154 	bool pending_reconnect = false;
1155 
1156 	noreclaim_flag = memalloc_noreclaim_save();
1157 	cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
1158 
1159 	length = atomic_inc_return(&tcpSesAllocCount);
1160 	if (length > 1)
1161 		mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
1162 
1163 	set_freezable();
1164 	allow_kernel_signal(SIGKILL);
1165 	while (server->tcpStatus != CifsExiting) {
1166 		if (try_to_freeze())
1167 			continue;
1168 
1169 		if (!allocate_buffers(server))
1170 			continue;
1171 
1172 		server->large_buf = false;
1173 		buf = server->smallbuf;
1174 		pdu_length = 4; /* enough to get RFC1001 header */
1175 
1176 		length = cifs_read_from_socket(server, buf, pdu_length);
1177 		if (length < 0)
1178 			continue;
1179 
1180 		if (is_smb1(server))
1181 			server->total_read = length;
1182 		else
1183 			server->total_read = 0;
1184 
1185 		/*
1186 		 * The right amount was read from socket - 4 bytes,
1187 		 * so we can now interpret the length field.
1188 		 */
1189 		pdu_length = get_rfc1002_length(buf);
1190 
1191 		cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
1192 		if (!is_smb_response(server, buf[0]))
1193 			continue;
1194 
1195 		pending_reconnect = false;
1196 next_pdu:
1197 		server->pdu_size = pdu_length;
1198 
1199 		/* make sure we have enough to get to the MID */
1200 		if (server->pdu_size < MID_HEADER_SIZE(server)) {
1201 			cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
1202 				 server->pdu_size);
1203 			cifs_reconnect(server, true);
1204 			continue;
1205 		}
1206 
1207 		/* read down to the MID */
1208 		length = cifs_read_from_socket(server,
1209 			     buf + HEADER_PREAMBLE_SIZE(server),
1210 			     MID_HEADER_SIZE(server));
1211 		if (length < 0)
1212 			continue;
1213 		server->total_read += length;
1214 
1215 		if (server->ops->next_header) {
1216 			next_offset = server->ops->next_header(buf);
1217 			if (next_offset)
1218 				server->pdu_size = next_offset;
1219 		}
1220 
1221 		memset(mids, 0, sizeof(mids));
1222 		memset(bufs, 0, sizeof(bufs));
1223 		num_mids = 0;
1224 
1225 		if (server->ops->is_transform_hdr &&
1226 		    server->ops->receive_transform &&
1227 		    server->ops->is_transform_hdr(buf)) {
1228 			length = server->ops->receive_transform(server,
1229 								mids,
1230 								bufs,
1231 								&num_mids);
1232 		} else {
1233 			mids[0] = server->ops->find_mid(server, buf);
1234 			bufs[0] = buf;
1235 			num_mids = 1;
1236 
1237 			if (!mids[0] || !mids[0]->receive)
1238 				length = standard_receive3(server, mids[0]);
1239 			else
1240 				length = mids[0]->receive(server, mids[0]);
1241 		}
1242 
1243 		if (length < 0) {
1244 			for (i = 0; i < num_mids; i++)
1245 				if (mids[i])
1246 					release_mid(mids[i]);
1247 			continue;
1248 		}
1249 
1250 		if (server->ops->is_status_io_timeout &&
1251 		    server->ops->is_status_io_timeout(buf)) {
1252 			num_io_timeout++;
1253 			if (num_io_timeout > MAX_STATUS_IO_TIMEOUT) {
1254 				cifs_server_dbg(VFS,
1255 						"Number of request timeouts exceeded %d. Reconnecting",
1256 						MAX_STATUS_IO_TIMEOUT);
1257 
1258 				pending_reconnect = true;
1259 				num_io_timeout = 0;
1260 			}
1261 		}
1262 
1263 		server->lstrp = jiffies;
1264 
1265 		for (i = 0; i < num_mids; i++) {
1266 			if (mids[i] != NULL) {
1267 				mids[i]->resp_buf_size = server->pdu_size;
1268 
1269 				if (bufs[i] != NULL) {
1270 					if (server->ops->is_network_name_deleted &&
1271 					    server->ops->is_network_name_deleted(bufs[i],
1272 										 server)) {
1273 						cifs_server_dbg(FYI,
1274 								"Share deleted. Reconnect needed");
1275 					}
1276 				}
1277 
1278 				if (!mids[i]->multiRsp || mids[i]->multiEnd)
1279 					mids[i]->callback(mids[i]);
1280 
1281 				release_mid(mids[i]);
1282 			} else if (server->ops->is_oplock_break &&
1283 				   server->ops->is_oplock_break(bufs[i],
1284 								server)) {
1285 				smb2_add_credits_from_hdr(bufs[i], server);
1286 				cifs_dbg(FYI, "Received oplock break\n");
1287 			} else {
1288 				cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
1289 						atomic_read(&mid_count));
1290 				cifs_dump_mem("Received Data is: ", bufs[i],
1291 					      HEADER_SIZE(server));
1292 				smb2_add_credits_from_hdr(bufs[i], server);
1293 #ifdef CONFIG_CIFS_DEBUG2
1294 				if (server->ops->dump_detail)
1295 					server->ops->dump_detail(bufs[i],
1296 								 server);
1297 				cifs_dump_mids(server);
1298 #endif /* CIFS_DEBUG2 */
1299 			}
1300 		}
1301 
1302 		if (pdu_length > server->pdu_size) {
1303 			if (!allocate_buffers(server))
1304 				continue;
1305 			pdu_length -= server->pdu_size;
1306 			server->total_read = 0;
1307 			server->large_buf = false;
1308 			buf = server->smallbuf;
1309 			goto next_pdu;
1310 		}
1311 
1312 		/* do this reconnect at the very end after processing all MIDs */
1313 		if (pending_reconnect)
1314 			cifs_reconnect(server, true);
1315 
1316 	} /* end while !EXITING */
1317 
1318 	/* buffer usually freed in free_mid - need to free it here on exit */
1319 	cifs_buf_release(server->bigbuf);
1320 	if (server->smallbuf) /* no sense logging a debug message if NULL */
1321 		cifs_small_buf_release(server->smallbuf);
1322 
1323 	task_to_wake = xchg(&server->tsk, NULL);
1324 	clean_demultiplex_info(server);
1325 
1326 	/* if server->tsk was NULL then wait for a signal before exiting */
1327 	if (!task_to_wake) {
1328 		set_current_state(TASK_INTERRUPTIBLE);
1329 		while (!signal_pending(current)) {
1330 			schedule();
1331 			set_current_state(TASK_INTERRUPTIBLE);
1332 		}
1333 		set_current_state(TASK_RUNNING);
1334 	}
1335 
1336 	memalloc_noreclaim_restore(noreclaim_flag);
1337 	module_put_and_kthread_exit(0);
1338 }
1339 
1340 int
1341 cifs_ipaddr_cmp(struct sockaddr *srcaddr, struct sockaddr *rhs)
1342 {
1343 	struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1344 	struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1345 	struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1346 	struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1347 
1348 	switch (srcaddr->sa_family) {
1349 	case AF_UNSPEC:
1350 		switch (rhs->sa_family) {
1351 		case AF_UNSPEC:
1352 			return 0;
1353 		case AF_INET:
1354 		case AF_INET6:
1355 			return 1;
1356 		default:
1357 			return -1;
1358 		}
1359 	case AF_INET: {
1360 		switch (rhs->sa_family) {
1361 		case AF_UNSPEC:
1362 			return -1;
1363 		case AF_INET:
1364 			return memcmp(saddr4, vaddr4,
1365 				      sizeof(struct sockaddr_in));
1366 		case AF_INET6:
1367 			return 1;
1368 		default:
1369 			return -1;
1370 		}
1371 	}
1372 	case AF_INET6: {
1373 		switch (rhs->sa_family) {
1374 		case AF_UNSPEC:
1375 		case AF_INET:
1376 			return -1;
1377 		case AF_INET6:
1378 			return memcmp(saddr6,
1379 				      vaddr6,
1380 				      sizeof(struct sockaddr_in6));
1381 		default:
1382 			return -1;
1383 		}
1384 	}
1385 	default:
1386 		return -1; /* don't expect to be here */
1387 	}
1388 }
1389 
1390 /*
1391  * Returns true if srcaddr isn't specified and rhs isn't specified, or
1392  * if srcaddr is specified and matches the IP address of the rhs argument
1393  */
1394 bool
1395 cifs_match_ipaddr(struct sockaddr *srcaddr, struct sockaddr *rhs)
1396 {
1397 	switch (srcaddr->sa_family) {
1398 	case AF_UNSPEC:
1399 		return (rhs->sa_family == AF_UNSPEC);
1400 	case AF_INET: {
1401 		struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1402 		struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1403 		return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
1404 	}
1405 	case AF_INET6: {
1406 		struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1407 		struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1408 		return (ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr)
1409 			&& saddr6->sin6_scope_id == vaddr6->sin6_scope_id);
1410 	}
1411 	default:
1412 		WARN_ON(1);
1413 		return false; /* don't expect to be here */
1414 	}
1415 }
1416 
1417 /*
1418  * If no port is specified in addr structure, we try to match with 445 port
1419  * and if it fails - with 139 ports. It should be called only if address
1420  * families of server and addr are equal.
1421  */
1422 static bool
1423 match_port(struct TCP_Server_Info *server, struct sockaddr *addr)
1424 {
1425 	__be16 port, *sport;
1426 
1427 	/* SMBDirect manages its own ports, don't match it here */
1428 	if (server->rdma)
1429 		return true;
1430 
1431 	switch (addr->sa_family) {
1432 	case AF_INET:
1433 		sport = &((struct sockaddr_in *) &server->dstaddr)->sin_port;
1434 		port = ((struct sockaddr_in *) addr)->sin_port;
1435 		break;
1436 	case AF_INET6:
1437 		sport = &((struct sockaddr_in6 *) &server->dstaddr)->sin6_port;
1438 		port = ((struct sockaddr_in6 *) addr)->sin6_port;
1439 		break;
1440 	default:
1441 		WARN_ON(1);
1442 		return false;
1443 	}
1444 
1445 	if (!port) {
1446 		port = htons(CIFS_PORT);
1447 		if (port == *sport)
1448 			return true;
1449 
1450 		port = htons(RFC1001_PORT);
1451 	}
1452 
1453 	return port == *sport;
1454 }
1455 
1456 static bool match_server_address(struct TCP_Server_Info *server, struct sockaddr *addr)
1457 {
1458 	if (!cifs_match_ipaddr(addr, (struct sockaddr *)&server->dstaddr))
1459 		return false;
1460 
1461 	return true;
1462 }
1463 
1464 static bool
1465 match_security(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1466 {
1467 	/*
1468 	 * The select_sectype function should either return the ctx->sectype
1469 	 * that was specified, or "Unspecified" if that sectype was not
1470 	 * compatible with the given NEGOTIATE request.
1471 	 */
1472 	if (server->ops->select_sectype(server, ctx->sectype)
1473 	     == Unspecified)
1474 		return false;
1475 
1476 	/*
1477 	 * Now check if signing mode is acceptable. No need to check
1478 	 * global_secflags at this point since if MUST_SIGN is set then
1479 	 * the server->sign had better be too.
1480 	 */
1481 	if (ctx->sign && !server->sign)
1482 		return false;
1483 
1484 	return true;
1485 }
1486 
1487 /* this function must be called with srv_lock held */
1488 static int match_server(struct TCP_Server_Info *server,
1489 			struct smb3_fs_context *ctx,
1490 			bool match_super)
1491 {
1492 	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
1493 
1494 	lockdep_assert_held(&server->srv_lock);
1495 
1496 	if (ctx->nosharesock)
1497 		return 0;
1498 
1499 	/* this server does not share socket */
1500 	if (server->nosharesock)
1501 		return 0;
1502 
1503 	/* If multidialect negotiation see if existing sessions match one */
1504 	if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
1505 		if (server->vals->protocol_id < SMB30_PROT_ID)
1506 			return 0;
1507 	} else if (strcmp(ctx->vals->version_string,
1508 		   SMBDEFAULT_VERSION_STRING) == 0) {
1509 		if (server->vals->protocol_id < SMB21_PROT_ID)
1510 			return 0;
1511 	} else if ((server->vals != ctx->vals) || (server->ops != ctx->ops))
1512 		return 0;
1513 
1514 	if (!net_eq(cifs_net_ns(server), current->nsproxy->net_ns))
1515 		return 0;
1516 
1517 	if (!cifs_match_ipaddr((struct sockaddr *)&ctx->srcaddr,
1518 			       (struct sockaddr *)&server->srcaddr))
1519 		return 0;
1520 	/*
1521 	 * When matching cifs.ko superblocks (@match_super == true), we can't
1522 	 * really match either @server->leaf_fullpath or @server->dstaddr
1523 	 * directly since this @server might belong to a completely different
1524 	 * server -- in case of domain-based DFS referrals or DFS links -- as
1525 	 * provided earlier by mount(2) through 'source' and 'ip' options.
1526 	 *
1527 	 * Otherwise, match the DFS referral in @server->leaf_fullpath or the
1528 	 * destination address in @server->dstaddr.
1529 	 *
1530 	 * When using 'nodfs' mount option, we avoid sharing it with DFS
1531 	 * connections as they might failover.
1532 	 */
1533 	if (!match_super) {
1534 		if (!ctx->nodfs) {
1535 			if (server->leaf_fullpath) {
1536 				if (!ctx->leaf_fullpath ||
1537 				    strcasecmp(server->leaf_fullpath,
1538 					       ctx->leaf_fullpath))
1539 					return 0;
1540 			} else if (ctx->leaf_fullpath) {
1541 				return 0;
1542 			}
1543 		} else if (server->leaf_fullpath) {
1544 			return 0;
1545 		}
1546 	}
1547 
1548 	/*
1549 	 * Match for a regular connection (address/hostname/port) which has no
1550 	 * DFS referrals set.
1551 	 */
1552 	if (!server->leaf_fullpath &&
1553 	    (strcasecmp(server->hostname, ctx->server_hostname) ||
1554 	     !match_server_address(server, addr) ||
1555 	     !match_port(server, addr)))
1556 		return 0;
1557 
1558 	if (!match_security(server, ctx))
1559 		return 0;
1560 
1561 	if (server->echo_interval != ctx->echo_interval * HZ)
1562 		return 0;
1563 
1564 	if (server->rdma != ctx->rdma)
1565 		return 0;
1566 
1567 	if (server->ignore_signature != ctx->ignore_signature)
1568 		return 0;
1569 
1570 	if (server->min_offload != ctx->min_offload)
1571 		return 0;
1572 
1573 	return 1;
1574 }
1575 
1576 struct TCP_Server_Info *
1577 cifs_find_tcp_session(struct smb3_fs_context *ctx)
1578 {
1579 	struct TCP_Server_Info *server;
1580 
1581 	spin_lock(&cifs_tcp_ses_lock);
1582 	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
1583 		spin_lock(&server->srv_lock);
1584 		/*
1585 		 * Skip ses channels since they're only handled in lower layers
1586 		 * (e.g. cifs_send_recv).
1587 		 */
1588 		if (SERVER_IS_CHAN(server) ||
1589 		    !match_server(server, ctx, false)) {
1590 			spin_unlock(&server->srv_lock);
1591 			continue;
1592 		}
1593 		spin_unlock(&server->srv_lock);
1594 
1595 		++server->srv_count;
1596 		spin_unlock(&cifs_tcp_ses_lock);
1597 		cifs_dbg(FYI, "Existing tcp session with server found\n");
1598 		return server;
1599 	}
1600 	spin_unlock(&cifs_tcp_ses_lock);
1601 	return NULL;
1602 }
1603 
1604 void
1605 cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
1606 {
1607 	struct task_struct *task;
1608 
1609 	spin_lock(&cifs_tcp_ses_lock);
1610 	if (--server->srv_count > 0) {
1611 		spin_unlock(&cifs_tcp_ses_lock);
1612 		return;
1613 	}
1614 
1615 	/* srv_count can never go negative */
1616 	WARN_ON(server->srv_count < 0);
1617 
1618 	put_net(cifs_net_ns(server));
1619 
1620 	list_del_init(&server->tcp_ses_list);
1621 	spin_unlock(&cifs_tcp_ses_lock);
1622 
1623 	/* For secondary channels, we pick up ref-count on the primary server */
1624 	if (SERVER_IS_CHAN(server))
1625 		cifs_put_tcp_session(server->primary_server, from_reconnect);
1626 
1627 	cancel_delayed_work_sync(&server->echo);
1628 
1629 	if (from_reconnect) {
1630 		/*
1631 		 * Avoid deadlock here: reconnect work calls
1632 		 * cifs_put_tcp_session() at its end. Need to be sure
1633 		 * that reconnect work does nothing with server pointer after
1634 		 * that step.
1635 		 */
1636 		if (cancel_delayed_work(&server->reconnect))
1637 			cifs_put_tcp_session(server, from_reconnect);
1638 	} else {
1639 		if (cancel_delayed_work_sync(&server->reconnect))
1640 			cifs_put_tcp_session(server, from_reconnect);
1641 	}
1642 
1643 	spin_lock(&server->srv_lock);
1644 	server->tcpStatus = CifsExiting;
1645 	spin_unlock(&server->srv_lock);
1646 
1647 	cifs_crypto_secmech_release(server);
1648 
1649 	kfree_sensitive(server->session_key.response);
1650 	server->session_key.response = NULL;
1651 	server->session_key.len = 0;
1652 	kfree(server->hostname);
1653 	server->hostname = NULL;
1654 
1655 	task = xchg(&server->tsk, NULL);
1656 	if (task)
1657 		send_sig(SIGKILL, task, 1);
1658 }
1659 
1660 struct TCP_Server_Info *
1661 cifs_get_tcp_session(struct smb3_fs_context *ctx,
1662 		     struct TCP_Server_Info *primary_server)
1663 {
1664 	struct TCP_Server_Info *tcp_ses = NULL;
1665 	int rc;
1666 
1667 	cifs_dbg(FYI, "UNC: %s\n", ctx->UNC);
1668 
1669 	/* see if we already have a matching tcp_ses */
1670 	tcp_ses = cifs_find_tcp_session(ctx);
1671 	if (tcp_ses)
1672 		return tcp_ses;
1673 
1674 	tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
1675 	if (!tcp_ses) {
1676 		rc = -ENOMEM;
1677 		goto out_err;
1678 	}
1679 
1680 	tcp_ses->hostname = kstrdup(ctx->server_hostname, GFP_KERNEL);
1681 	if (!tcp_ses->hostname) {
1682 		rc = -ENOMEM;
1683 		goto out_err;
1684 	}
1685 
1686 	if (ctx->leaf_fullpath) {
1687 		tcp_ses->leaf_fullpath = kstrdup(ctx->leaf_fullpath, GFP_KERNEL);
1688 		if (!tcp_ses->leaf_fullpath) {
1689 			rc = -ENOMEM;
1690 			goto out_err;
1691 		}
1692 	}
1693 
1694 	if (ctx->nosharesock)
1695 		tcp_ses->nosharesock = true;
1696 
1697 	tcp_ses->ops = ctx->ops;
1698 	tcp_ses->vals = ctx->vals;
1699 	cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
1700 
1701 	tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);
1702 	tcp_ses->noblockcnt = ctx->rootfs;
1703 	tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;
1704 	tcp_ses->noautotune = ctx->noautotune;
1705 	tcp_ses->tcp_nodelay = ctx->sockopt_tcp_nodelay;
1706 	tcp_ses->rdma = ctx->rdma;
1707 	tcp_ses->in_flight = 0;
1708 	tcp_ses->max_in_flight = 0;
1709 	tcp_ses->credits = 1;
1710 	if (primary_server) {
1711 		spin_lock(&cifs_tcp_ses_lock);
1712 		++primary_server->srv_count;
1713 		spin_unlock(&cifs_tcp_ses_lock);
1714 		tcp_ses->primary_server = primary_server;
1715 	}
1716 	init_waitqueue_head(&tcp_ses->response_q);
1717 	init_waitqueue_head(&tcp_ses->request_q);
1718 	INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
1719 	mutex_init(&tcp_ses->_srv_mutex);
1720 	memcpy(tcp_ses->workstation_RFC1001_name,
1721 		ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1722 	memcpy(tcp_ses->server_RFC1001_name,
1723 		ctx->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1724 	tcp_ses->session_estab = false;
1725 	tcp_ses->sequence_number = 0;
1726 	tcp_ses->channel_sequence_num = 0; /* only tracked for primary channel */
1727 	tcp_ses->reconnect_instance = 1;
1728 	tcp_ses->lstrp = jiffies;
1729 	tcp_ses->compress_algorithm = cpu_to_le16(ctx->compression);
1730 	spin_lock_init(&tcp_ses->req_lock);
1731 	spin_lock_init(&tcp_ses->srv_lock);
1732 	spin_lock_init(&tcp_ses->mid_lock);
1733 	INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
1734 	INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
1735 	INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
1736 	INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
1737 	mutex_init(&tcp_ses->reconnect_mutex);
1738 #ifdef CONFIG_CIFS_DFS_UPCALL
1739 	mutex_init(&tcp_ses->refpath_lock);
1740 #endif
1741 	memcpy(&tcp_ses->srcaddr, &ctx->srcaddr,
1742 	       sizeof(tcp_ses->srcaddr));
1743 	memcpy(&tcp_ses->dstaddr, &ctx->dstaddr,
1744 		sizeof(tcp_ses->dstaddr));
1745 	if (ctx->use_client_guid)
1746 		memcpy(tcp_ses->client_guid, ctx->client_guid,
1747 		       SMB2_CLIENT_GUID_SIZE);
1748 	else
1749 		generate_random_uuid(tcp_ses->client_guid);
1750 	/*
1751 	 * at this point we are the only ones with the pointer
1752 	 * to the struct since the kernel thread not created yet
1753 	 * no need to spinlock this init of tcpStatus or srv_count
1754 	 */
1755 	tcp_ses->tcpStatus = CifsNew;
1756 	++tcp_ses->srv_count;
1757 
1758 	if (ctx->echo_interval >= SMB_ECHO_INTERVAL_MIN &&
1759 		ctx->echo_interval <= SMB_ECHO_INTERVAL_MAX)
1760 		tcp_ses->echo_interval = ctx->echo_interval * HZ;
1761 	else
1762 		tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
1763 	if (tcp_ses->rdma) {
1764 #ifndef CONFIG_CIFS_SMB_DIRECT
1765 		cifs_dbg(VFS, "CONFIG_CIFS_SMB_DIRECT is not enabled\n");
1766 		rc = -ENOENT;
1767 		goto out_err_crypto_release;
1768 #endif
1769 		tcp_ses->smbd_conn = smbd_get_connection(
1770 			tcp_ses, (struct sockaddr *)&ctx->dstaddr);
1771 		if (tcp_ses->smbd_conn) {
1772 			cifs_dbg(VFS, "RDMA transport established\n");
1773 			rc = 0;
1774 			goto smbd_connected;
1775 		} else {
1776 			rc = -ENOENT;
1777 			goto out_err_crypto_release;
1778 		}
1779 	}
1780 	rc = ip_connect(tcp_ses);
1781 	if (rc < 0) {
1782 		cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
1783 		goto out_err_crypto_release;
1784 	}
1785 smbd_connected:
1786 	/*
1787 	 * since we're in a cifs function already, we know that
1788 	 * this will succeed. No need for try_module_get().
1789 	 */
1790 	__module_get(THIS_MODULE);
1791 	tcp_ses->tsk = kthread_run(cifs_demultiplex_thread,
1792 				  tcp_ses, "cifsd");
1793 	if (IS_ERR(tcp_ses->tsk)) {
1794 		rc = PTR_ERR(tcp_ses->tsk);
1795 		cifs_dbg(VFS, "error %d create cifsd thread\n", rc);
1796 		module_put(THIS_MODULE);
1797 		goto out_err_crypto_release;
1798 	}
1799 	tcp_ses->min_offload = ctx->min_offload;
1800 	/*
1801 	 * at this point we are the only ones with the pointer
1802 	 * to the struct since the kernel thread not created yet
1803 	 * no need to spinlock this update of tcpStatus
1804 	 */
1805 	spin_lock(&tcp_ses->srv_lock);
1806 	tcp_ses->tcpStatus = CifsNeedNegotiate;
1807 	spin_unlock(&tcp_ses->srv_lock);
1808 
1809 	if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
1810 		tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
1811 	else
1812 		tcp_ses->max_credits = ctx->max_credits;
1813 
1814 	tcp_ses->nr_targets = 1;
1815 	tcp_ses->ignore_signature = ctx->ignore_signature;
1816 	/* thread spawned, put it on the list */
1817 	spin_lock(&cifs_tcp_ses_lock);
1818 	list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
1819 	spin_unlock(&cifs_tcp_ses_lock);
1820 
1821 	/* queue echo request delayed work */
1822 	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
1823 
1824 	return tcp_ses;
1825 
1826 out_err_crypto_release:
1827 	cifs_crypto_secmech_release(tcp_ses);
1828 
1829 	put_net(cifs_net_ns(tcp_ses));
1830 
1831 out_err:
1832 	if (tcp_ses) {
1833 		if (SERVER_IS_CHAN(tcp_ses))
1834 			cifs_put_tcp_session(tcp_ses->primary_server, false);
1835 		kfree(tcp_ses->hostname);
1836 		kfree(tcp_ses->leaf_fullpath);
1837 		if (tcp_ses->ssocket)
1838 			sock_release(tcp_ses->ssocket);
1839 		kfree(tcp_ses);
1840 	}
1841 	return ERR_PTR(rc);
1842 }
1843 
1844 /* this function must be called with ses_lock and chan_lock held */
1845 static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1846 {
1847 	if (ctx->sectype != Unspecified &&
1848 	    ctx->sectype != ses->sectype)
1849 		return 0;
1850 
1851 	/*
1852 	 * If an existing session is limited to less channels than
1853 	 * requested, it should not be reused
1854 	 */
1855 	if (ses->chan_max < ctx->max_channels)
1856 		return 0;
1857 
1858 	switch (ses->sectype) {
1859 	case Kerberos:
1860 		if (!uid_eq(ctx->cred_uid, ses->cred_uid))
1861 			return 0;
1862 		break;
1863 	default:
1864 		/* NULL username means anonymous session */
1865 		if (ses->user_name == NULL) {
1866 			if (!ctx->nullauth)
1867 				return 0;
1868 			break;
1869 		}
1870 
1871 		/* anything else takes username/password */
1872 		if (strncmp(ses->user_name,
1873 			    ctx->username ? ctx->username : "",
1874 			    CIFS_MAX_USERNAME_LEN))
1875 			return 0;
1876 		if ((ctx->username && strlen(ctx->username) != 0) &&
1877 		    ses->password != NULL &&
1878 		    strncmp(ses->password,
1879 			    ctx->password ? ctx->password : "",
1880 			    CIFS_MAX_PASSWORD_LEN))
1881 			return 0;
1882 	}
1883 
1884 	if (strcmp(ctx->local_nls->charset, ses->local_nls->charset))
1885 		return 0;
1886 
1887 	return 1;
1888 }
1889 
1890 /**
1891  * cifs_setup_ipc - helper to setup the IPC tcon for the session
1892  * @ses: smb session to issue the request on
1893  * @ctx: the superblock configuration context to use for building the
1894  *       new tree connection for the IPC (interprocess communication RPC)
1895  *
1896  * A new IPC connection is made and stored in the session
1897  * tcon_ipc. The IPC tcon has the same lifetime as the session.
1898  */
1899 static int
1900 cifs_setup_ipc(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1901 {
1902 	int rc = 0, xid;
1903 	struct cifs_tcon *tcon;
1904 	char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
1905 	bool seal = false;
1906 	struct TCP_Server_Info *server = ses->server;
1907 
1908 	/*
1909 	 * If the mount request that resulted in the creation of the
1910 	 * session requires encryption, force IPC to be encrypted too.
1911 	 */
1912 	if (ctx->seal) {
1913 		if (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
1914 			seal = true;
1915 		else {
1916 			cifs_server_dbg(VFS,
1917 				 "IPC: server doesn't support encryption\n");
1918 			return -EOPNOTSUPP;
1919 		}
1920 	}
1921 
1922 	/* no need to setup directory caching on IPC share, so pass in false */
1923 	tcon = tcon_info_alloc(false);
1924 	if (tcon == NULL)
1925 		return -ENOMEM;
1926 
1927 	spin_lock(&server->srv_lock);
1928 	scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", server->hostname);
1929 	spin_unlock(&server->srv_lock);
1930 
1931 	xid = get_xid();
1932 	tcon->ses = ses;
1933 	tcon->ipc = true;
1934 	tcon->seal = seal;
1935 	rc = server->ops->tree_connect(xid, ses, unc, tcon, ctx->local_nls);
1936 	free_xid(xid);
1937 
1938 	if (rc) {
1939 		cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
1940 		tconInfoFree(tcon);
1941 		goto out;
1942 	}
1943 
1944 	cifs_dbg(FYI, "IPC tcon rc=%d ipc tid=0x%x\n", rc, tcon->tid);
1945 
1946 	spin_lock(&tcon->tc_lock);
1947 	tcon->status = TID_GOOD;
1948 	spin_unlock(&tcon->tc_lock);
1949 	ses->tcon_ipc = tcon;
1950 out:
1951 	return rc;
1952 }
1953 
1954 /**
1955  * cifs_free_ipc - helper to release the session IPC tcon
1956  * @ses: smb session to unmount the IPC from
1957  *
1958  * Needs to be called everytime a session is destroyed.
1959  *
1960  * On session close, the IPC is closed and the server must release all tcons of the session.
1961  * No need to send a tree disconnect here.
1962  *
1963  * Besides, it will make the server to not close durable and resilient files on session close, as
1964  * specified in MS-SMB2 3.3.5.6 Receiving an SMB2 LOGOFF Request.
1965  */
1966 static int
1967 cifs_free_ipc(struct cifs_ses *ses)
1968 {
1969 	struct cifs_tcon *tcon = ses->tcon_ipc;
1970 
1971 	if (tcon == NULL)
1972 		return 0;
1973 
1974 	tconInfoFree(tcon);
1975 	ses->tcon_ipc = NULL;
1976 	return 0;
1977 }
1978 
1979 static struct cifs_ses *
1980 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1981 {
1982 	struct cifs_ses *ses, *ret = NULL;
1983 
1984 	spin_lock(&cifs_tcp_ses_lock);
1985 	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1986 		spin_lock(&ses->ses_lock);
1987 		if (ses->ses_status == SES_EXITING) {
1988 			spin_unlock(&ses->ses_lock);
1989 			continue;
1990 		}
1991 		spin_lock(&ses->chan_lock);
1992 		if (match_session(ses, ctx)) {
1993 			spin_unlock(&ses->chan_lock);
1994 			spin_unlock(&ses->ses_lock);
1995 			ret = ses;
1996 			break;
1997 		}
1998 		spin_unlock(&ses->chan_lock);
1999 		spin_unlock(&ses->ses_lock);
2000 	}
2001 	if (ret)
2002 		cifs_smb_ses_inc_refcount(ret);
2003 	spin_unlock(&cifs_tcp_ses_lock);
2004 	return ret;
2005 }
2006 
2007 void __cifs_put_smb_ses(struct cifs_ses *ses)
2008 {
2009 	struct TCP_Server_Info *server = ses->server;
2010 	unsigned int xid;
2011 	size_t i;
2012 	int rc;
2013 
2014 	spin_lock(&ses->ses_lock);
2015 	if (ses->ses_status == SES_EXITING) {
2016 		spin_unlock(&ses->ses_lock);
2017 		return;
2018 	}
2019 	spin_unlock(&ses->ses_lock);
2020 
2021 	cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
2022 	cifs_dbg(FYI,
2023 		 "%s: ses ipc: %s\n", __func__, ses->tcon_ipc ? ses->tcon_ipc->tree_name : "NONE");
2024 
2025 	spin_lock(&cifs_tcp_ses_lock);
2026 	if (--ses->ses_count > 0) {
2027 		spin_unlock(&cifs_tcp_ses_lock);
2028 		return;
2029 	}
2030 	spin_lock(&ses->ses_lock);
2031 	if (ses->ses_status == SES_GOOD)
2032 		ses->ses_status = SES_EXITING;
2033 	spin_unlock(&ses->ses_lock);
2034 	spin_unlock(&cifs_tcp_ses_lock);
2035 
2036 	/* ses_count can never go negative */
2037 	WARN_ON(ses->ses_count < 0);
2038 
2039 	spin_lock(&ses->ses_lock);
2040 	if (ses->ses_status == SES_EXITING && server->ops->logoff) {
2041 		spin_unlock(&ses->ses_lock);
2042 		cifs_free_ipc(ses);
2043 		xid = get_xid();
2044 		rc = server->ops->logoff(xid, ses);
2045 		if (rc)
2046 			cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
2047 				__func__, rc);
2048 		_free_xid(xid);
2049 	} else {
2050 		spin_unlock(&ses->ses_lock);
2051 		cifs_free_ipc(ses);
2052 	}
2053 
2054 	spin_lock(&cifs_tcp_ses_lock);
2055 	list_del_init(&ses->smb_ses_list);
2056 	spin_unlock(&cifs_tcp_ses_lock);
2057 
2058 	/* close any extra channels */
2059 	for (i = 1; i < ses->chan_count; i++) {
2060 		if (ses->chans[i].iface) {
2061 			kref_put(&ses->chans[i].iface->refcount, release_iface);
2062 			ses->chans[i].iface = NULL;
2063 		}
2064 		cifs_put_tcp_session(ses->chans[i].server, 0);
2065 		ses->chans[i].server = NULL;
2066 	}
2067 
2068 	/* we now account for primary channel in iface->refcount */
2069 	if (ses->chans[0].iface) {
2070 		kref_put(&ses->chans[0].iface->refcount, release_iface);
2071 		ses->chans[0].server = NULL;
2072 	}
2073 
2074 	sesInfoFree(ses);
2075 	cifs_put_tcp_session(server, 0);
2076 }
2077 
2078 #ifdef CONFIG_KEYS
2079 
2080 /* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
2081 #define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
2082 
2083 /* Populate username and pw fields from keyring if possible */
2084 static int
2085 cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
2086 {
2087 	int rc = 0;
2088 	int is_domain = 0;
2089 	const char *delim, *payload;
2090 	char *desc;
2091 	ssize_t len;
2092 	struct key *key;
2093 	struct TCP_Server_Info *server = ses->server;
2094 	struct sockaddr_in *sa;
2095 	struct sockaddr_in6 *sa6;
2096 	const struct user_key_payload *upayload;
2097 
2098 	desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
2099 	if (!desc)
2100 		return -ENOMEM;
2101 
2102 	/* try to find an address key first */
2103 	switch (server->dstaddr.ss_family) {
2104 	case AF_INET:
2105 		sa = (struct sockaddr_in *)&server->dstaddr;
2106 		sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
2107 		break;
2108 	case AF_INET6:
2109 		sa6 = (struct sockaddr_in6 *)&server->dstaddr;
2110 		sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
2111 		break;
2112 	default:
2113 		cifs_dbg(FYI, "Bad ss_family (%hu)\n",
2114 			 server->dstaddr.ss_family);
2115 		rc = -EINVAL;
2116 		goto out_err;
2117 	}
2118 
2119 	cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
2120 	key = request_key(&key_type_logon, desc, "");
2121 	if (IS_ERR(key)) {
2122 		if (!ses->domainName) {
2123 			cifs_dbg(FYI, "domainName is NULL\n");
2124 			rc = PTR_ERR(key);
2125 			goto out_err;
2126 		}
2127 
2128 		/* didn't work, try to find a domain key */
2129 		sprintf(desc, "cifs:d:%s", ses->domainName);
2130 		cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
2131 		key = request_key(&key_type_logon, desc, "");
2132 		if (IS_ERR(key)) {
2133 			rc = PTR_ERR(key);
2134 			goto out_err;
2135 		}
2136 		is_domain = 1;
2137 	}
2138 
2139 	down_read(&key->sem);
2140 	upayload = user_key_payload_locked(key);
2141 	if (IS_ERR_OR_NULL(upayload)) {
2142 		rc = upayload ? PTR_ERR(upayload) : -EINVAL;
2143 		goto out_key_put;
2144 	}
2145 
2146 	/* find first : in payload */
2147 	payload = upayload->data;
2148 	delim = strnchr(payload, upayload->datalen, ':');
2149 	cifs_dbg(FYI, "payload=%s\n", payload);
2150 	if (!delim) {
2151 		cifs_dbg(FYI, "Unable to find ':' in payload (datalen=%d)\n",
2152 			 upayload->datalen);
2153 		rc = -EINVAL;
2154 		goto out_key_put;
2155 	}
2156 
2157 	len = delim - payload;
2158 	if (len > CIFS_MAX_USERNAME_LEN || len <= 0) {
2159 		cifs_dbg(FYI, "Bad value from username search (len=%zd)\n",
2160 			 len);
2161 		rc = -EINVAL;
2162 		goto out_key_put;
2163 	}
2164 
2165 	ctx->username = kstrndup(payload, len, GFP_KERNEL);
2166 	if (!ctx->username) {
2167 		cifs_dbg(FYI, "Unable to allocate %zd bytes for username\n",
2168 			 len);
2169 		rc = -ENOMEM;
2170 		goto out_key_put;
2171 	}
2172 	cifs_dbg(FYI, "%s: username=%s\n", __func__, ctx->username);
2173 
2174 	len = key->datalen - (len + 1);
2175 	if (len > CIFS_MAX_PASSWORD_LEN || len <= 0) {
2176 		cifs_dbg(FYI, "Bad len for password search (len=%zd)\n", len);
2177 		rc = -EINVAL;
2178 		kfree(ctx->username);
2179 		ctx->username = NULL;
2180 		goto out_key_put;
2181 	}
2182 
2183 	++delim;
2184 	ctx->password = kstrndup(delim, len, GFP_KERNEL);
2185 	if (!ctx->password) {
2186 		cifs_dbg(FYI, "Unable to allocate %zd bytes for password\n",
2187 			 len);
2188 		rc = -ENOMEM;
2189 		kfree(ctx->username);
2190 		ctx->username = NULL;
2191 		goto out_key_put;
2192 	}
2193 
2194 	/*
2195 	 * If we have a domain key then we must set the domainName in the
2196 	 * for the request.
2197 	 */
2198 	if (is_domain && ses->domainName) {
2199 		ctx->domainname = kstrdup(ses->domainName, GFP_KERNEL);
2200 		if (!ctx->domainname) {
2201 			cifs_dbg(FYI, "Unable to allocate %zd bytes for domain\n",
2202 				 len);
2203 			rc = -ENOMEM;
2204 			kfree(ctx->username);
2205 			ctx->username = NULL;
2206 			kfree_sensitive(ctx->password);
2207 			ctx->password = NULL;
2208 			goto out_key_put;
2209 		}
2210 	}
2211 
2212 	strscpy(ctx->workstation_name, ses->workstation_name, sizeof(ctx->workstation_name));
2213 
2214 out_key_put:
2215 	up_read(&key->sem);
2216 	key_put(key);
2217 out_err:
2218 	kfree(desc);
2219 	cifs_dbg(FYI, "%s: returning %d\n", __func__, rc);
2220 	return rc;
2221 }
2222 #else /* ! CONFIG_KEYS */
2223 static inline int
2224 cifs_set_cifscreds(struct smb3_fs_context *ctx __attribute__((unused)),
2225 		   struct cifs_ses *ses __attribute__((unused)))
2226 {
2227 	return -ENOSYS;
2228 }
2229 #endif /* CONFIG_KEYS */
2230 
2231 /**
2232  * cifs_get_smb_ses - get a session matching @ctx data from @server
2233  * @server: server to setup the session to
2234  * @ctx: superblock configuration context to use to setup the session
2235  *
2236  * This function assumes it is being called from cifs_mount() where we
2237  * already got a server reference (server refcount +1). See
2238  * cifs_get_tcon() for refcount explanations.
2239  */
2240 struct cifs_ses *
2241 cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
2242 {
2243 	int rc = 0;
2244 	unsigned int xid;
2245 	struct cifs_ses *ses;
2246 	struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
2247 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
2248 
2249 	xid = get_xid();
2250 
2251 	ses = cifs_find_smb_ses(server, ctx);
2252 	if (ses) {
2253 		cifs_dbg(FYI, "Existing smb sess found (status=%d)\n",
2254 			 ses->ses_status);
2255 
2256 		spin_lock(&ses->chan_lock);
2257 		if (cifs_chan_needs_reconnect(ses, server)) {
2258 			spin_unlock(&ses->chan_lock);
2259 			cifs_dbg(FYI, "Session needs reconnect\n");
2260 
2261 			mutex_lock(&ses->session_mutex);
2262 			rc = cifs_negotiate_protocol(xid, ses, server);
2263 			if (rc) {
2264 				mutex_unlock(&ses->session_mutex);
2265 				/* problem -- put our ses reference */
2266 				cifs_put_smb_ses(ses);
2267 				free_xid(xid);
2268 				return ERR_PTR(rc);
2269 			}
2270 
2271 			rc = cifs_setup_session(xid, ses, server,
2272 						ctx->local_nls);
2273 			if (rc) {
2274 				mutex_unlock(&ses->session_mutex);
2275 				/* problem -- put our reference */
2276 				cifs_put_smb_ses(ses);
2277 				free_xid(xid);
2278 				return ERR_PTR(rc);
2279 			}
2280 			mutex_unlock(&ses->session_mutex);
2281 
2282 			spin_lock(&ses->chan_lock);
2283 		}
2284 		spin_unlock(&ses->chan_lock);
2285 
2286 		/* existing SMB ses has a server reference already */
2287 		cifs_put_tcp_session(server, 0);
2288 		free_xid(xid);
2289 		return ses;
2290 	}
2291 
2292 	rc = -ENOMEM;
2293 
2294 	cifs_dbg(FYI, "Existing smb sess not found\n");
2295 	ses = sesInfoAlloc();
2296 	if (ses == NULL)
2297 		goto get_ses_fail;
2298 
2299 	/* new SMB session uses our server ref */
2300 	ses->server = server;
2301 	if (server->dstaddr.ss_family == AF_INET6)
2302 		sprintf(ses->ip_addr, "%pI6", &addr6->sin6_addr);
2303 	else
2304 		sprintf(ses->ip_addr, "%pI4", &addr->sin_addr);
2305 
2306 	if (ctx->username) {
2307 		ses->user_name = kstrdup(ctx->username, GFP_KERNEL);
2308 		if (!ses->user_name)
2309 			goto get_ses_fail;
2310 	}
2311 
2312 	/* ctx->password freed at unmount */
2313 	if (ctx->password) {
2314 		ses->password = kstrdup(ctx->password, GFP_KERNEL);
2315 		if (!ses->password)
2316 			goto get_ses_fail;
2317 	}
2318 	if (ctx->domainname) {
2319 		ses->domainName = kstrdup(ctx->domainname, GFP_KERNEL);
2320 		if (!ses->domainName)
2321 			goto get_ses_fail;
2322 	}
2323 
2324 	strscpy(ses->workstation_name, ctx->workstation_name, sizeof(ses->workstation_name));
2325 
2326 	if (ctx->domainauto)
2327 		ses->domainAuto = ctx->domainauto;
2328 	ses->cred_uid = ctx->cred_uid;
2329 	ses->linux_uid = ctx->linux_uid;
2330 
2331 	ses->sectype = ctx->sectype;
2332 	ses->sign = ctx->sign;
2333 	ses->local_nls = load_nls(ctx->local_nls->charset);
2334 
2335 	/* add server as first channel */
2336 	spin_lock(&ses->chan_lock);
2337 	ses->chans[0].server = server;
2338 	ses->chan_count = 1;
2339 	ses->chan_max = ctx->multichannel ? ctx->max_channels:1;
2340 	ses->chans_need_reconnect = 1;
2341 	spin_unlock(&ses->chan_lock);
2342 
2343 	mutex_lock(&ses->session_mutex);
2344 	rc = cifs_negotiate_protocol(xid, ses, server);
2345 	if (!rc)
2346 		rc = cifs_setup_session(xid, ses, server, ctx->local_nls);
2347 	mutex_unlock(&ses->session_mutex);
2348 
2349 	/* each channel uses a different signing key */
2350 	spin_lock(&ses->chan_lock);
2351 	memcpy(ses->chans[0].signkey, ses->smb3signingkey,
2352 	       sizeof(ses->smb3signingkey));
2353 	spin_unlock(&ses->chan_lock);
2354 
2355 	if (rc)
2356 		goto get_ses_fail;
2357 
2358 	/*
2359 	 * success, put it on the list and add it as first channel
2360 	 * note: the session becomes active soon after this. So you'll
2361 	 * need to lock before changing something in the session.
2362 	 */
2363 	spin_lock(&cifs_tcp_ses_lock);
2364 	ses->dfs_root_ses = ctx->dfs_root_ses;
2365 	if (ses->dfs_root_ses)
2366 		ses->dfs_root_ses->ses_count++;
2367 	list_add(&ses->smb_ses_list, &server->smb_ses_list);
2368 	spin_unlock(&cifs_tcp_ses_lock);
2369 
2370 	cifs_setup_ipc(ses, ctx);
2371 
2372 	free_xid(xid);
2373 
2374 	return ses;
2375 
2376 get_ses_fail:
2377 	sesInfoFree(ses);
2378 	free_xid(xid);
2379 	return ERR_PTR(rc);
2380 }
2381 
2382 /* this function must be called with tc_lock held */
2383 static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
2384 {
2385 	struct TCP_Server_Info *server = tcon->ses->server;
2386 
2387 	if (tcon->status == TID_EXITING)
2388 		return 0;
2389 
2390 	if (tcon->origin_fullpath) {
2391 		if (!ctx->source ||
2392 		    !dfs_src_pathname_equal(ctx->source,
2393 					    tcon->origin_fullpath))
2394 			return 0;
2395 	} else if (!server->leaf_fullpath &&
2396 		   strncmp(tcon->tree_name, ctx->UNC, MAX_TREE_SIZE)) {
2397 		return 0;
2398 	}
2399 	if (tcon->seal != ctx->seal)
2400 		return 0;
2401 	if (tcon->snapshot_time != ctx->snapshot_time)
2402 		return 0;
2403 	if (tcon->handle_timeout != ctx->handle_timeout)
2404 		return 0;
2405 	if (tcon->no_lease != ctx->no_lease)
2406 		return 0;
2407 	if (tcon->nodelete != ctx->nodelete)
2408 		return 0;
2409 	return 1;
2410 }
2411 
2412 static struct cifs_tcon *
2413 cifs_find_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2414 {
2415 	struct cifs_tcon *tcon;
2416 
2417 	spin_lock(&cifs_tcp_ses_lock);
2418 	list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
2419 		spin_lock(&tcon->tc_lock);
2420 		if (!match_tcon(tcon, ctx)) {
2421 			spin_unlock(&tcon->tc_lock);
2422 			continue;
2423 		}
2424 		++tcon->tc_count;
2425 		spin_unlock(&tcon->tc_lock);
2426 		spin_unlock(&cifs_tcp_ses_lock);
2427 		return tcon;
2428 	}
2429 	spin_unlock(&cifs_tcp_ses_lock);
2430 	return NULL;
2431 }
2432 
2433 void
2434 cifs_put_tcon(struct cifs_tcon *tcon)
2435 {
2436 	unsigned int xid;
2437 	struct cifs_ses *ses;
2438 
2439 	/*
2440 	 * IPC tcon share the lifetime of their session and are
2441 	 * destroyed in the session put function
2442 	 */
2443 	if (tcon == NULL || tcon->ipc)
2444 		return;
2445 
2446 	ses = tcon->ses;
2447 	cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
2448 	spin_lock(&cifs_tcp_ses_lock);
2449 	spin_lock(&tcon->tc_lock);
2450 	if (--tcon->tc_count > 0) {
2451 		spin_unlock(&tcon->tc_lock);
2452 		spin_unlock(&cifs_tcp_ses_lock);
2453 		return;
2454 	}
2455 
2456 	/* tc_count can never go negative */
2457 	WARN_ON(tcon->tc_count < 0);
2458 
2459 	list_del_init(&tcon->tcon_list);
2460 	tcon->status = TID_EXITING;
2461 	spin_unlock(&tcon->tc_lock);
2462 	spin_unlock(&cifs_tcp_ses_lock);
2463 
2464 	/* cancel polling of interfaces */
2465 	cancel_delayed_work_sync(&tcon->query_interfaces);
2466 #ifdef CONFIG_CIFS_DFS_UPCALL
2467 	cancel_delayed_work_sync(&tcon->dfs_cache_work);
2468 #endif
2469 
2470 	if (tcon->use_witness) {
2471 		int rc;
2472 
2473 		rc = cifs_swn_unregister(tcon);
2474 		if (rc < 0) {
2475 			cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
2476 					__func__, rc);
2477 		}
2478 	}
2479 
2480 	xid = get_xid();
2481 	if (ses->server->ops->tree_disconnect)
2482 		ses->server->ops->tree_disconnect(xid, tcon);
2483 	_free_xid(xid);
2484 
2485 	cifs_fscache_release_super_cookie(tcon);
2486 	tconInfoFree(tcon);
2487 	cifs_put_smb_ses(ses);
2488 }
2489 
2490 /**
2491  * cifs_get_tcon - get a tcon matching @ctx data from @ses
2492  * @ses: smb session to issue the request on
2493  * @ctx: the superblock configuration context to use for building the
2494  *
2495  * - tcon refcount is the number of mount points using the tcon.
2496  * - ses refcount is the number of tcon using the session.
2497  *
2498  * 1. This function assumes it is being called from cifs_mount() where
2499  *    we already got a session reference (ses refcount +1).
2500  *
2501  * 2. Since we're in the context of adding a mount point, the end
2502  *    result should be either:
2503  *
2504  * a) a new tcon already allocated with refcount=1 (1 mount point) and
2505  *    its session refcount incremented (1 new tcon). This +1 was
2506  *    already done in (1).
2507  *
2508  * b) an existing tcon with refcount+1 (add a mount point to it) and
2509  *    identical ses refcount (no new tcon). Because of (1) we need to
2510  *    decrement the ses refcount.
2511  */
2512 static struct cifs_tcon *
2513 cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2514 {
2515 	struct cifs_tcon *tcon;
2516 	bool nohandlecache;
2517 	int rc, xid;
2518 
2519 	tcon = cifs_find_tcon(ses, ctx);
2520 	if (tcon) {
2521 		/*
2522 		 * tcon has refcount already incremented but we need to
2523 		 * decrement extra ses reference gotten by caller (case b)
2524 		 */
2525 		cifs_dbg(FYI, "Found match on UNC path\n");
2526 		cifs_put_smb_ses(ses);
2527 		return tcon;
2528 	}
2529 
2530 	if (!ses->server->ops->tree_connect) {
2531 		rc = -ENOSYS;
2532 		goto out_fail;
2533 	}
2534 
2535 	if (ses->server->dialect >= SMB20_PROT_ID &&
2536 	    (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING))
2537 		nohandlecache = ctx->nohandlecache;
2538 	else
2539 		nohandlecache = true;
2540 	tcon = tcon_info_alloc(!nohandlecache);
2541 	if (tcon == NULL) {
2542 		rc = -ENOMEM;
2543 		goto out_fail;
2544 	}
2545 	tcon->nohandlecache = nohandlecache;
2546 
2547 	if (ctx->snapshot_time) {
2548 		if (ses->server->vals->protocol_id == 0) {
2549 			cifs_dbg(VFS,
2550 			     "Use SMB2 or later for snapshot mount option\n");
2551 			rc = -EOPNOTSUPP;
2552 			goto out_fail;
2553 		} else
2554 			tcon->snapshot_time = ctx->snapshot_time;
2555 	}
2556 
2557 	if (ctx->handle_timeout) {
2558 		if (ses->server->vals->protocol_id == 0) {
2559 			cifs_dbg(VFS,
2560 			     "Use SMB2.1 or later for handle timeout option\n");
2561 			rc = -EOPNOTSUPP;
2562 			goto out_fail;
2563 		} else
2564 			tcon->handle_timeout = ctx->handle_timeout;
2565 	}
2566 
2567 	tcon->ses = ses;
2568 	if (ctx->password) {
2569 		tcon->password = kstrdup(ctx->password, GFP_KERNEL);
2570 		if (!tcon->password) {
2571 			rc = -ENOMEM;
2572 			goto out_fail;
2573 		}
2574 	}
2575 
2576 	if (ctx->seal) {
2577 		if (ses->server->vals->protocol_id == 0) {
2578 			cifs_dbg(VFS,
2579 				 "SMB3 or later required for encryption\n");
2580 			rc = -EOPNOTSUPP;
2581 			goto out_fail;
2582 		} else if (tcon->ses->server->capabilities &
2583 					SMB2_GLOBAL_CAP_ENCRYPTION)
2584 			tcon->seal = true;
2585 		else {
2586 			cifs_dbg(VFS, "Encryption is not supported on share\n");
2587 			rc = -EOPNOTSUPP;
2588 			goto out_fail;
2589 		}
2590 	}
2591 
2592 	if (ctx->linux_ext) {
2593 		if (ses->server->posix_ext_supported) {
2594 			tcon->posix_extensions = true;
2595 			pr_warn_once("SMB3.11 POSIX Extensions are experimental\n");
2596 		} else if ((ses->server->vals->protocol_id == SMB311_PROT_ID) ||
2597 		    (strcmp(ses->server->vals->version_string,
2598 		     SMB3ANY_VERSION_STRING) == 0) ||
2599 		    (strcmp(ses->server->vals->version_string,
2600 		     SMBDEFAULT_VERSION_STRING) == 0)) {
2601 			cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions\n");
2602 			rc = -EOPNOTSUPP;
2603 			goto out_fail;
2604 		} else {
2605 			cifs_dbg(VFS, "Check vers= mount option. SMB3.11 "
2606 				"disabled but required for POSIX extensions\n");
2607 			rc = -EOPNOTSUPP;
2608 			goto out_fail;
2609 		}
2610 	}
2611 
2612 	xid = get_xid();
2613 	rc = ses->server->ops->tree_connect(xid, ses, ctx->UNC, tcon,
2614 					    ctx->local_nls);
2615 	free_xid(xid);
2616 	cifs_dbg(FYI, "Tcon rc = %d\n", rc);
2617 	if (rc)
2618 		goto out_fail;
2619 
2620 	tcon->use_persistent = false;
2621 	/* check if SMB2 or later, CIFS does not support persistent handles */
2622 	if (ctx->persistent) {
2623 		if (ses->server->vals->protocol_id == 0) {
2624 			cifs_dbg(VFS,
2625 			     "SMB3 or later required for persistent handles\n");
2626 			rc = -EOPNOTSUPP;
2627 			goto out_fail;
2628 		} else if (ses->server->capabilities &
2629 			   SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2630 			tcon->use_persistent = true;
2631 		else /* persistent handles requested but not supported */ {
2632 			cifs_dbg(VFS,
2633 				"Persistent handles not supported on share\n");
2634 			rc = -EOPNOTSUPP;
2635 			goto out_fail;
2636 		}
2637 	} else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
2638 	     && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2639 	     && (ctx->nopersistent == false)) {
2640 		cifs_dbg(FYI, "enabling persistent handles\n");
2641 		tcon->use_persistent = true;
2642 	} else if (ctx->resilient) {
2643 		if (ses->server->vals->protocol_id == 0) {
2644 			cifs_dbg(VFS,
2645 			     "SMB2.1 or later required for resilient handles\n");
2646 			rc = -EOPNOTSUPP;
2647 			goto out_fail;
2648 		}
2649 		tcon->use_resilient = true;
2650 	}
2651 
2652 	tcon->use_witness = false;
2653 	if (IS_ENABLED(CONFIG_CIFS_SWN_UPCALL) && ctx->witness) {
2654 		if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
2655 			if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
2656 				/*
2657 				 * Set witness in use flag in first place
2658 				 * to retry registration in the echo task
2659 				 */
2660 				tcon->use_witness = true;
2661 				/* And try to register immediately */
2662 				rc = cifs_swn_register(tcon);
2663 				if (rc < 0) {
2664 					cifs_dbg(VFS, "Failed to register for witness notifications: %d\n", rc);
2665 					goto out_fail;
2666 				}
2667 			} else {
2668 				/* TODO: try to extend for non-cluster uses (eg multichannel) */
2669 				cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
2670 				rc = -EOPNOTSUPP;
2671 				goto out_fail;
2672 			}
2673 		} else {
2674 			cifs_dbg(VFS, "SMB3 or later required for witness option\n");
2675 			rc = -EOPNOTSUPP;
2676 			goto out_fail;
2677 		}
2678 	}
2679 
2680 	/* If the user really knows what they are doing they can override */
2681 	if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
2682 		if (ctx->cache_ro)
2683 			cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING flag set on share\n");
2684 		else if (ctx->cache_rw)
2685 			cifs_dbg(VFS, "cache=singleclient requested on mount but NO_CACHING flag set on share\n");
2686 	}
2687 
2688 	if (ctx->no_lease) {
2689 		if (ses->server->vals->protocol_id == 0) {
2690 			cifs_dbg(VFS,
2691 				"SMB2 or later required for nolease option\n");
2692 			rc = -EOPNOTSUPP;
2693 			goto out_fail;
2694 		} else
2695 			tcon->no_lease = ctx->no_lease;
2696 	}
2697 
2698 	/*
2699 	 * We can have only one retry value for a connection to a share so for
2700 	 * resources mounted more than once to the same server share the last
2701 	 * value passed in for the retry flag is used.
2702 	 */
2703 	tcon->retry = ctx->retry;
2704 	tcon->nocase = ctx->nocase;
2705 	tcon->broken_sparse_sup = ctx->no_sparse;
2706 	tcon->max_cached_dirs = ctx->max_cached_dirs;
2707 	tcon->nodelete = ctx->nodelete;
2708 	tcon->local_lease = ctx->local_lease;
2709 	INIT_LIST_HEAD(&tcon->pending_opens);
2710 	tcon->status = TID_GOOD;
2711 
2712 	INIT_DELAYED_WORK(&tcon->query_interfaces,
2713 			  smb2_query_server_interfaces);
2714 	if (ses->server->dialect >= SMB30_PROT_ID &&
2715 	    (ses->server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
2716 		/* schedule query interfaces poll */
2717 		queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
2718 				   (SMB_INTERFACE_POLL_INTERVAL * HZ));
2719 	}
2720 #ifdef CONFIG_CIFS_DFS_UPCALL
2721 	INIT_DELAYED_WORK(&tcon->dfs_cache_work, dfs_cache_refresh);
2722 #endif
2723 	spin_lock(&cifs_tcp_ses_lock);
2724 	list_add(&tcon->tcon_list, &ses->tcon_list);
2725 	spin_unlock(&cifs_tcp_ses_lock);
2726 
2727 	return tcon;
2728 
2729 out_fail:
2730 	tconInfoFree(tcon);
2731 	return ERR_PTR(rc);
2732 }
2733 
2734 void
2735 cifs_put_tlink(struct tcon_link *tlink)
2736 {
2737 	if (!tlink || IS_ERR(tlink))
2738 		return;
2739 
2740 	if (!atomic_dec_and_test(&tlink->tl_count) ||
2741 	    test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
2742 		tlink->tl_time = jiffies;
2743 		return;
2744 	}
2745 
2746 	if (!IS_ERR(tlink_tcon(tlink)))
2747 		cifs_put_tcon(tlink_tcon(tlink));
2748 	kfree(tlink);
2749 	return;
2750 }
2751 
2752 static int
2753 compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2754 {
2755 	struct cifs_sb_info *old = CIFS_SB(sb);
2756 	struct cifs_sb_info *new = mnt_data->cifs_sb;
2757 	unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
2758 	unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;
2759 
2760 	if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
2761 		return 0;
2762 
2763 	if (old->mnt_cifs_serverino_autodisabled)
2764 		newflags &= ~CIFS_MOUNT_SERVER_INUM;
2765 
2766 	if (oldflags != newflags)
2767 		return 0;
2768 
2769 	/*
2770 	 * We want to share sb only if we don't specify an r/wsize or
2771 	 * specified r/wsize is greater than or equal to existing one.
2772 	 */
2773 	if (new->ctx->wsize && new->ctx->wsize < old->ctx->wsize)
2774 		return 0;
2775 
2776 	if (new->ctx->rsize && new->ctx->rsize < old->ctx->rsize)
2777 		return 0;
2778 
2779 	if (!uid_eq(old->ctx->linux_uid, new->ctx->linux_uid) ||
2780 	    !gid_eq(old->ctx->linux_gid, new->ctx->linux_gid))
2781 		return 0;
2782 
2783 	if (old->ctx->file_mode != new->ctx->file_mode ||
2784 	    old->ctx->dir_mode != new->ctx->dir_mode)
2785 		return 0;
2786 
2787 	if (strcmp(old->local_nls->charset, new->local_nls->charset))
2788 		return 0;
2789 
2790 	if (old->ctx->acregmax != new->ctx->acregmax)
2791 		return 0;
2792 	if (old->ctx->acdirmax != new->ctx->acdirmax)
2793 		return 0;
2794 	if (old->ctx->closetimeo != new->ctx->closetimeo)
2795 		return 0;
2796 
2797 	return 1;
2798 }
2799 
2800 static int match_prepath(struct super_block *sb,
2801 			 struct cifs_tcon *tcon,
2802 			 struct cifs_mnt_data *mnt_data)
2803 {
2804 	struct smb3_fs_context *ctx = mnt_data->ctx;
2805 	struct cifs_sb_info *old = CIFS_SB(sb);
2806 	struct cifs_sb_info *new = mnt_data->cifs_sb;
2807 	bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2808 		old->prepath;
2809 	bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2810 		new->prepath;
2811 
2812 	if (tcon->origin_fullpath &&
2813 	    dfs_src_pathname_equal(tcon->origin_fullpath, ctx->source))
2814 		return 1;
2815 
2816 	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
2817 		return 1;
2818 	else if (!old_set && !new_set)
2819 		return 1;
2820 
2821 	return 0;
2822 }
2823 
2824 int
2825 cifs_match_super(struct super_block *sb, void *data)
2826 {
2827 	struct cifs_mnt_data *mnt_data = data;
2828 	struct smb3_fs_context *ctx;
2829 	struct cifs_sb_info *cifs_sb;
2830 	struct TCP_Server_Info *tcp_srv;
2831 	struct cifs_ses *ses;
2832 	struct cifs_tcon *tcon;
2833 	struct tcon_link *tlink;
2834 	int rc = 0;
2835 
2836 	spin_lock(&cifs_tcp_ses_lock);
2837 	cifs_sb = CIFS_SB(sb);
2838 
2839 	/* We do not want to use a superblock that has been shutdown */
2840 	if (CIFS_MOUNT_SHUTDOWN & cifs_sb->mnt_cifs_flags) {
2841 		spin_unlock(&cifs_tcp_ses_lock);
2842 		return 0;
2843 	}
2844 
2845 	tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
2846 	if (IS_ERR_OR_NULL(tlink)) {
2847 		pr_warn_once("%s: skip super matching due to bad tlink(%p)\n",
2848 			     __func__, tlink);
2849 		spin_unlock(&cifs_tcp_ses_lock);
2850 		return 0;
2851 	}
2852 	tcon = tlink_tcon(tlink);
2853 	ses = tcon->ses;
2854 	tcp_srv = ses->server;
2855 
2856 	ctx = mnt_data->ctx;
2857 
2858 	spin_lock(&tcp_srv->srv_lock);
2859 	spin_lock(&ses->ses_lock);
2860 	spin_lock(&ses->chan_lock);
2861 	spin_lock(&tcon->tc_lock);
2862 	if (!match_server(tcp_srv, ctx, true) ||
2863 	    !match_session(ses, ctx) ||
2864 	    !match_tcon(tcon, ctx) ||
2865 	    !match_prepath(sb, tcon, mnt_data)) {
2866 		rc = 0;
2867 		goto out;
2868 	}
2869 
2870 	rc = compare_mount_options(sb, mnt_data);
2871 out:
2872 	spin_unlock(&tcon->tc_lock);
2873 	spin_unlock(&ses->chan_lock);
2874 	spin_unlock(&ses->ses_lock);
2875 	spin_unlock(&tcp_srv->srv_lock);
2876 
2877 	spin_unlock(&cifs_tcp_ses_lock);
2878 	cifs_put_tlink(tlink);
2879 	return rc;
2880 }
2881 
2882 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2883 static struct lock_class_key cifs_key[2];
2884 static struct lock_class_key cifs_slock_key[2];
2885 
2886 static inline void
2887 cifs_reclassify_socket4(struct socket *sock)
2888 {
2889 	struct sock *sk = sock->sk;
2890 	BUG_ON(!sock_allow_reclassification(sk));
2891 	sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS",
2892 		&cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]);
2893 }
2894 
2895 static inline void
2896 cifs_reclassify_socket6(struct socket *sock)
2897 {
2898 	struct sock *sk = sock->sk;
2899 	BUG_ON(!sock_allow_reclassification(sk));
2900 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS",
2901 		&cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]);
2902 }
2903 #else
2904 static inline void
2905 cifs_reclassify_socket4(struct socket *sock)
2906 {
2907 }
2908 
2909 static inline void
2910 cifs_reclassify_socket6(struct socket *sock)
2911 {
2912 }
2913 #endif
2914 
2915 /* See RFC1001 section 14 on representation of Netbios names */
2916 static void rfc1002mangle(char *target, char *source, unsigned int length)
2917 {
2918 	unsigned int i, j;
2919 
2920 	for (i = 0, j = 0; i < (length); i++) {
2921 		/* mask a nibble at a time and encode */
2922 		target[j] = 'A' + (0x0F & (source[i] >> 4));
2923 		target[j+1] = 'A' + (0x0F & source[i]);
2924 		j += 2;
2925 	}
2926 
2927 }
2928 
2929 static int
2930 bind_socket(struct TCP_Server_Info *server)
2931 {
2932 	int rc = 0;
2933 	if (server->srcaddr.ss_family != AF_UNSPEC) {
2934 		/* Bind to the specified local IP address */
2935 		struct socket *socket = server->ssocket;
2936 		rc = kernel_bind(socket,
2937 				 (struct sockaddr *) &server->srcaddr,
2938 				 sizeof(server->srcaddr));
2939 		if (rc < 0) {
2940 			struct sockaddr_in *saddr4;
2941 			struct sockaddr_in6 *saddr6;
2942 			saddr4 = (struct sockaddr_in *)&server->srcaddr;
2943 			saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
2944 			if (saddr6->sin6_family == AF_INET6)
2945 				cifs_server_dbg(VFS, "Failed to bind to: %pI6c, error: %d\n",
2946 					 &saddr6->sin6_addr, rc);
2947 			else
2948 				cifs_server_dbg(VFS, "Failed to bind to: %pI4, error: %d\n",
2949 					 &saddr4->sin_addr.s_addr, rc);
2950 		}
2951 	}
2952 	return rc;
2953 }
2954 
2955 static int
2956 ip_rfc1001_connect(struct TCP_Server_Info *server)
2957 {
2958 	int rc = 0;
2959 	/*
2960 	 * some servers require RFC1001 sessinit before sending
2961 	 * negprot - BB check reconnection in case where second
2962 	 * sessinit is sent but no second negprot
2963 	 */
2964 	struct rfc1002_session_packet req = {};
2965 	struct smb_hdr *smb_buf = (struct smb_hdr *)&req;
2966 	unsigned int len;
2967 
2968 	req.trailer.session_req.called_len = sizeof(req.trailer.session_req.called_name);
2969 
2970 	if (server->server_RFC1001_name[0] != 0)
2971 		rfc1002mangle(req.trailer.session_req.called_name,
2972 			      server->server_RFC1001_name,
2973 			      RFC1001_NAME_LEN_WITH_NULL);
2974 	else
2975 		rfc1002mangle(req.trailer.session_req.called_name,
2976 			      DEFAULT_CIFS_CALLED_NAME,
2977 			      RFC1001_NAME_LEN_WITH_NULL);
2978 
2979 	req.trailer.session_req.calling_len = sizeof(req.trailer.session_req.calling_name);
2980 
2981 	/* calling name ends in null (byte 16) from old smb convention */
2982 	if (server->workstation_RFC1001_name[0] != 0)
2983 		rfc1002mangle(req.trailer.session_req.calling_name,
2984 			      server->workstation_RFC1001_name,
2985 			      RFC1001_NAME_LEN_WITH_NULL);
2986 	else
2987 		rfc1002mangle(req.trailer.session_req.calling_name,
2988 			      "LINUX_CIFS_CLNT",
2989 			      RFC1001_NAME_LEN_WITH_NULL);
2990 
2991 	/*
2992 	 * As per rfc1002, @len must be the number of bytes that follows the
2993 	 * length field of a rfc1002 session request payload.
2994 	 */
2995 	len = sizeof(req) - offsetof(struct rfc1002_session_packet, trailer.session_req);
2996 
2997 	smb_buf->smb_buf_length = cpu_to_be32((RFC1002_SESSION_REQUEST << 24) | len);
2998 	rc = smb_send(server, smb_buf, len);
2999 	/*
3000 	 * RFC1001 layer in at least one server requires very short break before
3001 	 * negprot presumably because not expecting negprot to follow so fast.
3002 	 * This is a simple solution that works without complicating the code
3003 	 * and causes no significant slowing down on mount for everyone else
3004 	 */
3005 	usleep_range(1000, 2000);
3006 
3007 	return rc;
3008 }
3009 
3010 static int
3011 generic_ip_connect(struct TCP_Server_Info *server)
3012 {
3013 	struct sockaddr *saddr;
3014 	struct socket *socket;
3015 	int slen, sfamily;
3016 	__be16 sport;
3017 	int rc = 0;
3018 
3019 	saddr = (struct sockaddr *) &server->dstaddr;
3020 
3021 	if (server->dstaddr.ss_family == AF_INET6) {
3022 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&server->dstaddr;
3023 
3024 		sport = ipv6->sin6_port;
3025 		slen = sizeof(struct sockaddr_in6);
3026 		sfamily = AF_INET6;
3027 		cifs_dbg(FYI, "%s: connecting to [%pI6]:%d\n", __func__, &ipv6->sin6_addr,
3028 				ntohs(sport));
3029 	} else {
3030 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)&server->dstaddr;
3031 
3032 		sport = ipv4->sin_port;
3033 		slen = sizeof(struct sockaddr_in);
3034 		sfamily = AF_INET;
3035 		cifs_dbg(FYI, "%s: connecting to %pI4:%d\n", __func__, &ipv4->sin_addr,
3036 				ntohs(sport));
3037 	}
3038 
3039 	if (server->ssocket) {
3040 		socket = server->ssocket;
3041 	} else {
3042 		rc = __sock_create(cifs_net_ns(server), sfamily, SOCK_STREAM,
3043 				   IPPROTO_TCP, &server->ssocket, 1);
3044 		if (rc < 0) {
3045 			cifs_server_dbg(VFS, "Error %d creating socket\n", rc);
3046 			return rc;
3047 		}
3048 
3049 		/* BB other socket options to set KEEPALIVE, NODELAY? */
3050 		cifs_dbg(FYI, "Socket created\n");
3051 		socket = server->ssocket;
3052 		socket->sk->sk_allocation = GFP_NOFS;
3053 		socket->sk->sk_use_task_frag = false;
3054 		if (sfamily == AF_INET6)
3055 			cifs_reclassify_socket6(socket);
3056 		else
3057 			cifs_reclassify_socket4(socket);
3058 	}
3059 
3060 	rc = bind_socket(server);
3061 	if (rc < 0)
3062 		return rc;
3063 
3064 	/*
3065 	 * Eventually check for other socket options to change from
3066 	 * the default. sock_setsockopt not used because it expects
3067 	 * user space buffer
3068 	 */
3069 	socket->sk->sk_rcvtimeo = 7 * HZ;
3070 	socket->sk->sk_sndtimeo = 5 * HZ;
3071 
3072 	/* make the bufsizes depend on wsize/rsize and max requests */
3073 	if (server->noautotune) {
3074 		if (socket->sk->sk_sndbuf < (200 * 1024))
3075 			socket->sk->sk_sndbuf = 200 * 1024;
3076 		if (socket->sk->sk_rcvbuf < (140 * 1024))
3077 			socket->sk->sk_rcvbuf = 140 * 1024;
3078 	}
3079 
3080 	if (server->tcp_nodelay)
3081 		tcp_sock_set_nodelay(socket->sk);
3082 
3083 	cifs_dbg(FYI, "sndbuf %d rcvbuf %d rcvtimeo 0x%lx\n",
3084 		 socket->sk->sk_sndbuf,
3085 		 socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
3086 
3087 	rc = kernel_connect(socket, saddr, slen,
3088 			    server->noblockcnt ? O_NONBLOCK : 0);
3089 	/*
3090 	 * When mounting SMB root file systems, we do not want to block in
3091 	 * connect. Otherwise bail out and then let cifs_reconnect() perform
3092 	 * reconnect failover - if possible.
3093 	 */
3094 	if (server->noblockcnt && rc == -EINPROGRESS)
3095 		rc = 0;
3096 	if (rc < 0) {
3097 		cifs_dbg(FYI, "Error %d connecting to server\n", rc);
3098 		trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
3099 		sock_release(socket);
3100 		server->ssocket = NULL;
3101 		return rc;
3102 	}
3103 	trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
3104 	if (sport == htons(RFC1001_PORT))
3105 		rc = ip_rfc1001_connect(server);
3106 
3107 	return rc;
3108 }
3109 
3110 static int
3111 ip_connect(struct TCP_Server_Info *server)
3112 {
3113 	__be16 *sport;
3114 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
3115 	struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
3116 
3117 	if (server->dstaddr.ss_family == AF_INET6)
3118 		sport = &addr6->sin6_port;
3119 	else
3120 		sport = &addr->sin_port;
3121 
3122 	if (*sport == 0) {
3123 		int rc;
3124 
3125 		/* try with 445 port at first */
3126 		*sport = htons(CIFS_PORT);
3127 
3128 		rc = generic_ip_connect(server);
3129 		if (rc >= 0)
3130 			return rc;
3131 
3132 		/* if it failed, try with 139 port */
3133 		*sport = htons(RFC1001_PORT);
3134 	}
3135 
3136 	return generic_ip_connect(server);
3137 }
3138 
3139 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
3140 void reset_cifs_unix_caps(unsigned int xid, struct cifs_tcon *tcon,
3141 			  struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3142 {
3143 	/*
3144 	 * If we are reconnecting then should we check to see if
3145 	 * any requested capabilities changed locally e.g. via
3146 	 * remount but we can not do much about it here
3147 	 * if they have (even if we could detect it by the following)
3148 	 * Perhaps we could add a backpointer to array of sb from tcon
3149 	 * or if we change to make all sb to same share the same
3150 	 * sb as NFS - then we only have one backpointer to sb.
3151 	 * What if we wanted to mount the server share twice once with
3152 	 * and once without posixacls or posix paths?
3153 	 */
3154 	__u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
3155 
3156 	if (ctx && ctx->no_linux_ext) {
3157 		tcon->fsUnixInfo.Capability = 0;
3158 		tcon->unix_ext = 0; /* Unix Extensions disabled */
3159 		cifs_dbg(FYI, "Linux protocol extensions disabled\n");
3160 		return;
3161 	} else if (ctx)
3162 		tcon->unix_ext = 1; /* Unix Extensions supported */
3163 
3164 	if (!tcon->unix_ext) {
3165 		cifs_dbg(FYI, "Unix extensions disabled so not set on reconnect\n");
3166 		return;
3167 	}
3168 
3169 	if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
3170 		__u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
3171 		cifs_dbg(FYI, "unix caps which server supports %lld\n", cap);
3172 		/*
3173 		 * check for reconnect case in which we do not
3174 		 * want to change the mount behavior if we can avoid it
3175 		 */
3176 		if (ctx == NULL) {
3177 			/*
3178 			 * turn off POSIX ACL and PATHNAMES if not set
3179 			 * originally at mount time
3180 			 */
3181 			if ((saved_cap & CIFS_UNIX_POSIX_ACL_CAP) == 0)
3182 				cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
3183 			if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
3184 				if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
3185 					cifs_dbg(VFS, "POSIXPATH support change\n");
3186 				cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
3187 			} else if ((cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
3188 				cifs_dbg(VFS, "possible reconnect error\n");
3189 				cifs_dbg(VFS, "server disabled POSIX path support\n");
3190 			}
3191 		}
3192 
3193 		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
3194 			cifs_dbg(VFS, "per-share encryption not supported yet\n");
3195 
3196 		cap &= CIFS_UNIX_CAP_MASK;
3197 		if (ctx && ctx->no_psx_acl)
3198 			cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
3199 		else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
3200 			cifs_dbg(FYI, "negotiated posix acl support\n");
3201 			if (cifs_sb)
3202 				cifs_sb->mnt_cifs_flags |=
3203 					CIFS_MOUNT_POSIXACL;
3204 		}
3205 
3206 		if (ctx && ctx->posix_paths == 0)
3207 			cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
3208 		else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
3209 			cifs_dbg(FYI, "negotiate posix pathnames\n");
3210 			if (cifs_sb)
3211 				cifs_sb->mnt_cifs_flags |=
3212 					CIFS_MOUNT_POSIX_PATHS;
3213 		}
3214 
3215 		cifs_dbg(FYI, "Negotiate caps 0x%x\n", (int)cap);
3216 #ifdef CONFIG_CIFS_DEBUG2
3217 		if (cap & CIFS_UNIX_FCNTL_CAP)
3218 			cifs_dbg(FYI, "FCNTL cap\n");
3219 		if (cap & CIFS_UNIX_EXTATTR_CAP)
3220 			cifs_dbg(FYI, "EXTATTR cap\n");
3221 		if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
3222 			cifs_dbg(FYI, "POSIX path cap\n");
3223 		if (cap & CIFS_UNIX_XATTR_CAP)
3224 			cifs_dbg(FYI, "XATTR cap\n");
3225 		if (cap & CIFS_UNIX_POSIX_ACL_CAP)
3226 			cifs_dbg(FYI, "POSIX ACL cap\n");
3227 		if (cap & CIFS_UNIX_LARGE_READ_CAP)
3228 			cifs_dbg(FYI, "very large read cap\n");
3229 		if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
3230 			cifs_dbg(FYI, "very large write cap\n");
3231 		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
3232 			cifs_dbg(FYI, "transport encryption cap\n");
3233 		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
3234 			cifs_dbg(FYI, "mandatory transport encryption cap\n");
3235 #endif /* CIFS_DEBUG2 */
3236 		if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
3237 			if (ctx == NULL)
3238 				cifs_dbg(FYI, "resetting capabilities failed\n");
3239 			else
3240 				cifs_dbg(VFS, "Negotiating Unix capabilities with the server failed. Consider mounting with the Unix Extensions disabled if problems are found by specifying the nounix mount option.\n");
3241 
3242 		}
3243 	}
3244 }
3245 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
3246 
3247 int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb)
3248 {
3249 	struct smb3_fs_context *ctx = cifs_sb->ctx;
3250 
3251 	INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
3252 
3253 	spin_lock_init(&cifs_sb->tlink_tree_lock);
3254 	cifs_sb->tlink_tree = RB_ROOT;
3255 
3256 	cifs_dbg(FYI, "file mode: %04ho  dir mode: %04ho\n",
3257 		 ctx->file_mode, ctx->dir_mode);
3258 
3259 	/* this is needed for ASCII cp to Unicode converts */
3260 	if (ctx->iocharset == NULL) {
3261 		/* load_nls_default cannot return null */
3262 		cifs_sb->local_nls = load_nls_default();
3263 	} else {
3264 		cifs_sb->local_nls = load_nls(ctx->iocharset);
3265 		if (cifs_sb->local_nls == NULL) {
3266 			cifs_dbg(VFS, "CIFS mount error: iocharset %s not found\n",
3267 				 ctx->iocharset);
3268 			return -ELIBACC;
3269 		}
3270 	}
3271 	ctx->local_nls = cifs_sb->local_nls;
3272 
3273 	smb3_update_mnt_flags(cifs_sb);
3274 
3275 	if (ctx->direct_io)
3276 		cifs_dbg(FYI, "mounting share using direct i/o\n");
3277 	if (ctx->cache_ro) {
3278 		cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
3279 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
3280 	} else if (ctx->cache_rw) {
3281 		cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
3282 		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
3283 					    CIFS_MOUNT_RW_CACHE);
3284 	}
3285 
3286 	if ((ctx->cifs_acl) && (ctx->dynperm))
3287 		cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
3288 
3289 	if (ctx->prepath) {
3290 		cifs_sb->prepath = kstrdup(ctx->prepath, GFP_KERNEL);
3291 		if (cifs_sb->prepath == NULL)
3292 			return -ENOMEM;
3293 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3294 	}
3295 
3296 	return 0;
3297 }
3298 
3299 /* Release all succeed connections */
3300 void cifs_mount_put_conns(struct cifs_mount_ctx *mnt_ctx)
3301 {
3302 	int rc = 0;
3303 
3304 	if (mnt_ctx->tcon)
3305 		cifs_put_tcon(mnt_ctx->tcon);
3306 	else if (mnt_ctx->ses)
3307 		cifs_put_smb_ses(mnt_ctx->ses);
3308 	else if (mnt_ctx->server)
3309 		cifs_put_tcp_session(mnt_ctx->server, 0);
3310 	mnt_ctx->cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
3311 	free_xid(mnt_ctx->xid);
3312 }
3313 
3314 int cifs_mount_get_session(struct cifs_mount_ctx *mnt_ctx)
3315 {
3316 	struct TCP_Server_Info *server = NULL;
3317 	struct smb3_fs_context *ctx;
3318 	struct cifs_ses *ses = NULL;
3319 	unsigned int xid;
3320 	int rc = 0;
3321 
3322 	xid = get_xid();
3323 
3324 	if (WARN_ON_ONCE(!mnt_ctx || !mnt_ctx->fs_ctx)) {
3325 		rc = -EINVAL;
3326 		goto out;
3327 	}
3328 	ctx = mnt_ctx->fs_ctx;
3329 
3330 	/* get a reference to a tcp session */
3331 	server = cifs_get_tcp_session(ctx, NULL);
3332 	if (IS_ERR(server)) {
3333 		rc = PTR_ERR(server);
3334 		server = NULL;
3335 		goto out;
3336 	}
3337 
3338 	/* get a reference to a SMB session */
3339 	ses = cifs_get_smb_ses(server, ctx);
3340 	if (IS_ERR(ses)) {
3341 		rc = PTR_ERR(ses);
3342 		ses = NULL;
3343 		goto out;
3344 	}
3345 
3346 	if ((ctx->persistent == true) && (!(ses->server->capabilities &
3347 					    SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
3348 		cifs_server_dbg(VFS, "persistent handles not supported by server\n");
3349 		rc = -EOPNOTSUPP;
3350 	}
3351 
3352 out:
3353 	mnt_ctx->xid = xid;
3354 	mnt_ctx->server = server;
3355 	mnt_ctx->ses = ses;
3356 	mnt_ctx->tcon = NULL;
3357 
3358 	return rc;
3359 }
3360 
3361 int cifs_mount_get_tcon(struct cifs_mount_ctx *mnt_ctx)
3362 {
3363 	struct TCP_Server_Info *server;
3364 	struct cifs_sb_info *cifs_sb;
3365 	struct smb3_fs_context *ctx;
3366 	struct cifs_tcon *tcon = NULL;
3367 	int rc = 0;
3368 
3369 	if (WARN_ON_ONCE(!mnt_ctx || !mnt_ctx->server || !mnt_ctx->ses || !mnt_ctx->fs_ctx ||
3370 			 !mnt_ctx->cifs_sb)) {
3371 		rc = -EINVAL;
3372 		goto out;
3373 	}
3374 	server = mnt_ctx->server;
3375 	ctx = mnt_ctx->fs_ctx;
3376 	cifs_sb = mnt_ctx->cifs_sb;
3377 
3378 	/* search for existing tcon to this server share */
3379 	tcon = cifs_get_tcon(mnt_ctx->ses, ctx);
3380 	if (IS_ERR(tcon)) {
3381 		rc = PTR_ERR(tcon);
3382 		tcon = NULL;
3383 		goto out;
3384 	}
3385 
3386 	/* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
3387 	if (tcon->posix_extensions)
3388 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
3389 
3390 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
3391 	/* tell server which Unix caps we support */
3392 	if (cap_unix(tcon->ses)) {
3393 		/*
3394 		 * reset of caps checks mount to see if unix extensions disabled
3395 		 * for just this mount.
3396 		 */
3397 		reset_cifs_unix_caps(mnt_ctx->xid, tcon, cifs_sb, ctx);
3398 		spin_lock(&tcon->ses->server->srv_lock);
3399 		if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
3400 		    (le64_to_cpu(tcon->fsUnixInfo.Capability) &
3401 		     CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
3402 			spin_unlock(&tcon->ses->server->srv_lock);
3403 			rc = -EACCES;
3404 			goto out;
3405 		}
3406 		spin_unlock(&tcon->ses->server->srv_lock);
3407 	} else
3408 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
3409 		tcon->unix_ext = 0; /* server does not support them */
3410 
3411 	/* do not care if a following call succeed - informational */
3412 	if (!tcon->pipe && server->ops->qfs_tcon) {
3413 		server->ops->qfs_tcon(mnt_ctx->xid, tcon, cifs_sb);
3414 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE) {
3415 			if (tcon->fsDevInfo.DeviceCharacteristics &
3416 			    cpu_to_le32(FILE_READ_ONLY_DEVICE))
3417 				cifs_dbg(VFS, "mounted to read only share\n");
3418 			else if ((cifs_sb->mnt_cifs_flags &
3419 				  CIFS_MOUNT_RW_CACHE) == 0)
3420 				cifs_dbg(VFS, "read only mount of RW share\n");
3421 			/* no need to log a RW mount of a typical RW share */
3422 		}
3423 	}
3424 
3425 	/*
3426 	 * Clamp the rsize/wsize mount arguments if they are too big for the server
3427 	 * and set the rsize/wsize to the negotiated values if not passed in by
3428 	 * the user on mount
3429 	 */
3430 	if ((cifs_sb->ctx->wsize == 0) ||
3431 	    (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx)))
3432 		cifs_sb->ctx->wsize = server->ops->negotiate_wsize(tcon, ctx);
3433 	if ((cifs_sb->ctx->rsize == 0) ||
3434 	    (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
3435 		cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
3436 
3437 	/*
3438 	 * The cookie is initialized from volume info returned above.
3439 	 * Inside cifs_fscache_get_super_cookie it checks
3440 	 * that we do not get super cookie twice.
3441 	 */
3442 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE)
3443 		cifs_fscache_get_super_cookie(tcon);
3444 
3445 out:
3446 	mnt_ctx->tcon = tcon;
3447 	return rc;
3448 }
3449 
3450 static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
3451 			     struct cifs_tcon *tcon)
3452 {
3453 	struct tcon_link *tlink;
3454 
3455 	/* hang the tcon off of the superblock */
3456 	tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
3457 	if (tlink == NULL)
3458 		return -ENOMEM;
3459 
3460 	tlink->tl_uid = ses->linux_uid;
3461 	tlink->tl_tcon = tcon;
3462 	tlink->tl_time = jiffies;
3463 	set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
3464 	set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3465 
3466 	cifs_sb->master_tlink = tlink;
3467 	spin_lock(&cifs_sb->tlink_tree_lock);
3468 	tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
3469 	spin_unlock(&cifs_sb->tlink_tree_lock);
3470 
3471 	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
3472 				TLINK_IDLE_EXPIRE);
3473 	return 0;
3474 }
3475 
3476 static int
3477 cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
3478 					unsigned int xid,
3479 					struct cifs_tcon *tcon,
3480 					struct cifs_sb_info *cifs_sb,
3481 					char *full_path,
3482 					int added_treename)
3483 {
3484 	int rc;
3485 	char *s;
3486 	char sep, tmp;
3487 	int skip = added_treename ? 1 : 0;
3488 
3489 	sep = CIFS_DIR_SEP(cifs_sb);
3490 	s = full_path;
3491 
3492 	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
3493 	while (rc == 0) {
3494 		/* skip separators */
3495 		while (*s == sep)
3496 			s++;
3497 		if (!*s)
3498 			break;
3499 		/* next separator */
3500 		while (*s && *s != sep)
3501 			s++;
3502 		/*
3503 		 * if the treename is added, we then have to skip the first
3504 		 * part within the separators
3505 		 */
3506 		if (skip) {
3507 			skip = 0;
3508 			continue;
3509 		}
3510 		/*
3511 		 * temporarily null-terminate the path at the end of
3512 		 * the current component
3513 		 */
3514 		tmp = *s;
3515 		*s = 0;
3516 		rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3517 						     full_path);
3518 		*s = tmp;
3519 	}
3520 	return rc;
3521 }
3522 
3523 /*
3524  * Check if path is remote (i.e. a DFS share).
3525  *
3526  * Return -EREMOTE if it is, otherwise 0 or -errno.
3527  */
3528 int cifs_is_path_remote(struct cifs_mount_ctx *mnt_ctx)
3529 {
3530 	int rc;
3531 	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3532 	struct TCP_Server_Info *server = mnt_ctx->server;
3533 	unsigned int xid = mnt_ctx->xid;
3534 	struct cifs_tcon *tcon = mnt_ctx->tcon;
3535 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3536 	char *full_path;
3537 
3538 	if (!server->ops->is_path_accessible)
3539 		return -EOPNOTSUPP;
3540 
3541 	/*
3542 	 * cifs_build_path_to_root works only when we have a valid tcon
3543 	 */
3544 	full_path = cifs_build_path_to_root(ctx, cifs_sb, tcon,
3545 					    tcon->Flags & SMB_SHARE_IS_IN_DFS);
3546 	if (full_path == NULL)
3547 		return -ENOMEM;
3548 
3549 	cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
3550 
3551 	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3552 					     full_path);
3553 	if (rc != 0 && rc != -EREMOTE)
3554 		goto out;
3555 
3556 	if (rc != -EREMOTE) {
3557 		rc = cifs_are_all_path_components_accessible(server, xid, tcon,
3558 			cifs_sb, full_path, tcon->Flags & SMB_SHARE_IS_IN_DFS);
3559 		if (rc != 0) {
3560 			cifs_server_dbg(VFS, "cannot query dirs between root and final path, enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
3561 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3562 			rc = 0;
3563 		}
3564 	}
3565 
3566 out:
3567 	kfree(full_path);
3568 	return rc;
3569 }
3570 
3571 #ifdef CONFIG_CIFS_DFS_UPCALL
3572 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3573 {
3574 	struct cifs_mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
3575 	bool isdfs;
3576 	int rc;
3577 
3578 	INIT_LIST_HEAD(&mnt_ctx.dfs_ses_list);
3579 
3580 	rc = dfs_mount_share(&mnt_ctx, &isdfs);
3581 	if (rc)
3582 		goto error;
3583 	if (!isdfs)
3584 		goto out;
3585 
3586 	/*
3587 	 * After reconnecting to a different server, unique ids won't match anymore, so we disable
3588 	 * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
3589 	 */
3590 	cifs_autodisable_serverino(cifs_sb);
3591 	/*
3592 	 * Force the use of prefix path to support failover on DFS paths that resolve to targets
3593 	 * that have different prefix paths.
3594 	 */
3595 	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3596 	kfree(cifs_sb->prepath);
3597 	cifs_sb->prepath = ctx->prepath;
3598 	ctx->prepath = NULL;
3599 
3600 out:
3601 	cifs_try_adding_channels(mnt_ctx.ses);
3602 	rc = mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
3603 	if (rc)
3604 		goto error;
3605 
3606 	free_xid(mnt_ctx.xid);
3607 	return rc;
3608 
3609 error:
3610 	dfs_put_root_smb_sessions(&mnt_ctx.dfs_ses_list);
3611 	cifs_mount_put_conns(&mnt_ctx);
3612 	return rc;
3613 }
3614 #else
3615 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3616 {
3617 	int rc = 0;
3618 	struct cifs_mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
3619 
3620 	rc = cifs_mount_get_session(&mnt_ctx);
3621 	if (rc)
3622 		goto error;
3623 
3624 	rc = cifs_mount_get_tcon(&mnt_ctx);
3625 	if (rc)
3626 		goto error;
3627 
3628 	rc = cifs_is_path_remote(&mnt_ctx);
3629 	if (rc == -EREMOTE)
3630 		rc = -EOPNOTSUPP;
3631 	if (rc)
3632 		goto error;
3633 
3634 	rc = mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
3635 	if (rc)
3636 		goto error;
3637 
3638 	free_xid(mnt_ctx.xid);
3639 	return rc;
3640 
3641 error:
3642 	cifs_mount_put_conns(&mnt_ctx);
3643 	return rc;
3644 }
3645 #endif
3646 
3647 /*
3648  * Issue a TREE_CONNECT request.
3649  */
3650 int
3651 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
3652 	 const char *tree, struct cifs_tcon *tcon,
3653 	 const struct nls_table *nls_codepage)
3654 {
3655 	struct smb_hdr *smb_buffer;
3656 	struct smb_hdr *smb_buffer_response;
3657 	TCONX_REQ *pSMB;
3658 	TCONX_RSP *pSMBr;
3659 	unsigned char *bcc_ptr;
3660 	int rc = 0;
3661 	int length;
3662 	__u16 bytes_left, count;
3663 
3664 	if (ses == NULL)
3665 		return -EIO;
3666 
3667 	smb_buffer = cifs_buf_get();
3668 	if (smb_buffer == NULL)
3669 		return -ENOMEM;
3670 
3671 	smb_buffer_response = smb_buffer;
3672 
3673 	header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
3674 			NULL /*no tid */ , 4 /*wct */ );
3675 
3676 	smb_buffer->Mid = get_next_mid(ses->server);
3677 	smb_buffer->Uid = ses->Suid;
3678 	pSMB = (TCONX_REQ *) smb_buffer;
3679 	pSMBr = (TCONX_RSP *) smb_buffer_response;
3680 
3681 	pSMB->AndXCommand = 0xFF;
3682 	pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
3683 	bcc_ptr = &pSMB->Password[0];
3684 
3685 	pSMB->PasswordLength = cpu_to_le16(1);	/* minimum */
3686 	*bcc_ptr = 0; /* password is null byte */
3687 	bcc_ptr++;              /* skip password */
3688 	/* already aligned so no need to do it below */
3689 
3690 	if (ses->server->sign)
3691 		smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
3692 
3693 	if (ses->capabilities & CAP_STATUS32) {
3694 		smb_buffer->Flags2 |= SMBFLG2_ERR_STATUS;
3695 	}
3696 	if (ses->capabilities & CAP_DFS) {
3697 		smb_buffer->Flags2 |= SMBFLG2_DFS;
3698 	}
3699 	if (ses->capabilities & CAP_UNICODE) {
3700 		smb_buffer->Flags2 |= SMBFLG2_UNICODE;
3701 		length =
3702 		    cifs_strtoUTF16((__le16 *) bcc_ptr, tree,
3703 			6 /* max utf8 char length in bytes */ *
3704 			(/* server len*/ + 256 /* share len */), nls_codepage);
3705 		bcc_ptr += 2 * length;	/* convert num 16 bit words to bytes */
3706 		bcc_ptr += 2;	/* skip trailing null */
3707 	} else {		/* ASCII */
3708 		strcpy(bcc_ptr, tree);
3709 		bcc_ptr += strlen(tree) + 1;
3710 	}
3711 	strcpy(bcc_ptr, "?????");
3712 	bcc_ptr += strlen("?????");
3713 	bcc_ptr += 1;
3714 	count = bcc_ptr - &pSMB->Password[0];
3715 	be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
3716 	pSMB->ByteCount = cpu_to_le16(count);
3717 
3718 	rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,
3719 			 0);
3720 
3721 	/* above now done in SendReceive */
3722 	if (rc == 0) {
3723 		bool is_unicode;
3724 
3725 		tcon->tid = smb_buffer_response->Tid;
3726 		bcc_ptr = pByteArea(smb_buffer_response);
3727 		bytes_left = get_bcc(smb_buffer_response);
3728 		length = strnlen(bcc_ptr, bytes_left - 2);
3729 		if (smb_buffer->Flags2 & SMBFLG2_UNICODE)
3730 			is_unicode = true;
3731 		else
3732 			is_unicode = false;
3733 
3734 
3735 		/* skip service field (NB: this field is always ASCII) */
3736 		if (length == 3) {
3737 			if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
3738 			    (bcc_ptr[2] == 'C')) {
3739 				cifs_dbg(FYI, "IPC connection\n");
3740 				tcon->ipc = true;
3741 				tcon->pipe = true;
3742 			}
3743 		} else if (length == 2) {
3744 			if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
3745 				/* the most common case */
3746 				cifs_dbg(FYI, "disk share connection\n");
3747 			}
3748 		}
3749 		bcc_ptr += length + 1;
3750 		bytes_left -= (length + 1);
3751 		strscpy(tcon->tree_name, tree, sizeof(tcon->tree_name));
3752 
3753 		/* mostly informational -- no need to fail on error here */
3754 		kfree(tcon->nativeFileSystem);
3755 		tcon->nativeFileSystem = cifs_strndup_from_utf16(bcc_ptr,
3756 						      bytes_left, is_unicode,
3757 						      nls_codepage);
3758 
3759 		cifs_dbg(FYI, "nativeFileSystem=%s\n", tcon->nativeFileSystem);
3760 
3761 		if ((smb_buffer_response->WordCount == 3) ||
3762 			 (smb_buffer_response->WordCount == 7))
3763 			/* field is in same location */
3764 			tcon->Flags = le16_to_cpu(pSMBr->OptionalSupport);
3765 		else
3766 			tcon->Flags = 0;
3767 		cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
3768 	}
3769 
3770 	cifs_buf_release(smb_buffer);
3771 	return rc;
3772 }
3773 
3774 static void delayed_free(struct rcu_head *p)
3775 {
3776 	struct cifs_sb_info *cifs_sb = container_of(p, struct cifs_sb_info, rcu);
3777 
3778 	unload_nls(cifs_sb->local_nls);
3779 	smb3_cleanup_fs_context(cifs_sb->ctx);
3780 	kfree(cifs_sb);
3781 }
3782 
3783 void
3784 cifs_umount(struct cifs_sb_info *cifs_sb)
3785 {
3786 	struct rb_root *root = &cifs_sb->tlink_tree;
3787 	struct rb_node *node;
3788 	struct tcon_link *tlink;
3789 
3790 	cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
3791 
3792 	spin_lock(&cifs_sb->tlink_tree_lock);
3793 	while ((node = rb_first(root))) {
3794 		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
3795 		cifs_get_tlink(tlink);
3796 		clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3797 		rb_erase(node, root);
3798 
3799 		spin_unlock(&cifs_sb->tlink_tree_lock);
3800 		cifs_put_tlink(tlink);
3801 		spin_lock(&cifs_sb->tlink_tree_lock);
3802 	}
3803 	spin_unlock(&cifs_sb->tlink_tree_lock);
3804 
3805 	kfree(cifs_sb->prepath);
3806 	call_rcu(&cifs_sb->rcu, delayed_free);
3807 }
3808 
3809 int
3810 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses,
3811 			struct TCP_Server_Info *server)
3812 {
3813 	int rc = 0;
3814 
3815 	if (!server->ops->need_neg || !server->ops->negotiate)
3816 		return -ENOSYS;
3817 
3818 	/* only send once per connect */
3819 	spin_lock(&server->srv_lock);
3820 	if (server->tcpStatus != CifsGood &&
3821 	    server->tcpStatus != CifsNew &&
3822 	    server->tcpStatus != CifsNeedNegotiate) {
3823 		spin_unlock(&server->srv_lock);
3824 		return -EHOSTDOWN;
3825 	}
3826 
3827 	if (!server->ops->need_neg(server) &&
3828 	    server->tcpStatus == CifsGood) {
3829 		spin_unlock(&server->srv_lock);
3830 		return 0;
3831 	}
3832 
3833 	server->tcpStatus = CifsInNegotiate;
3834 	spin_unlock(&server->srv_lock);
3835 
3836 	rc = server->ops->negotiate(xid, ses, server);
3837 	if (rc == 0) {
3838 		spin_lock(&server->srv_lock);
3839 		if (server->tcpStatus == CifsInNegotiate)
3840 			server->tcpStatus = CifsGood;
3841 		else
3842 			rc = -EHOSTDOWN;
3843 		spin_unlock(&server->srv_lock);
3844 	} else {
3845 		spin_lock(&server->srv_lock);
3846 		if (server->tcpStatus == CifsInNegotiate)
3847 			server->tcpStatus = CifsNeedNegotiate;
3848 		spin_unlock(&server->srv_lock);
3849 	}
3850 
3851 	return rc;
3852 }
3853 
3854 int
3855 cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
3856 		   struct TCP_Server_Info *server,
3857 		   struct nls_table *nls_info)
3858 {
3859 	int rc = -ENOSYS;
3860 	struct TCP_Server_Info *pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
3861 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&pserver->dstaddr;
3862 	struct sockaddr_in *addr = (struct sockaddr_in *)&pserver->dstaddr;
3863 	bool is_binding = false;
3864 
3865 	spin_lock(&ses->ses_lock);
3866 	cifs_dbg(FYI, "%s: channel connect bitmap: 0x%lx\n",
3867 		 __func__, ses->chans_need_reconnect);
3868 
3869 	if (ses->ses_status != SES_GOOD &&
3870 	    ses->ses_status != SES_NEW &&
3871 	    ses->ses_status != SES_NEED_RECON) {
3872 		spin_unlock(&ses->ses_lock);
3873 		return -EHOSTDOWN;
3874 	}
3875 
3876 	/* only send once per connect */
3877 	spin_lock(&ses->chan_lock);
3878 	if (CIFS_ALL_CHANS_GOOD(ses)) {
3879 		if (ses->ses_status == SES_NEED_RECON)
3880 			ses->ses_status = SES_GOOD;
3881 		spin_unlock(&ses->chan_lock);
3882 		spin_unlock(&ses->ses_lock);
3883 		return 0;
3884 	}
3885 
3886 	cifs_chan_set_in_reconnect(ses, server);
3887 	is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
3888 	spin_unlock(&ses->chan_lock);
3889 
3890 	if (!is_binding) {
3891 		ses->ses_status = SES_IN_SETUP;
3892 
3893 		/* force iface_list refresh */
3894 		ses->iface_last_update = 0;
3895 	}
3896 	spin_unlock(&ses->ses_lock);
3897 
3898 	/* update ses ip_addr only for primary chan */
3899 	if (server == pserver) {
3900 		if (server->dstaddr.ss_family == AF_INET6)
3901 			scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI6", &addr6->sin6_addr);
3902 		else
3903 			scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI4", &addr->sin_addr);
3904 	}
3905 
3906 	if (!is_binding) {
3907 		ses->capabilities = server->capabilities;
3908 		if (!linuxExtEnabled)
3909 			ses->capabilities &= (~server->vals->cap_unix);
3910 
3911 		if (ses->auth_key.response) {
3912 			cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
3913 				 ses->auth_key.response);
3914 			kfree_sensitive(ses->auth_key.response);
3915 			ses->auth_key.response = NULL;
3916 			ses->auth_key.len = 0;
3917 		}
3918 	}
3919 
3920 	cifs_dbg(FYI, "Security Mode: 0x%x Capabilities: 0x%x TimeAdjust: %d\n",
3921 		 server->sec_mode, server->capabilities, server->timeAdj);
3922 
3923 	if (server->ops->sess_setup)
3924 		rc = server->ops->sess_setup(xid, ses, server, nls_info);
3925 
3926 	if (rc) {
3927 		cifs_server_dbg(VFS, "Send error in SessSetup = %d\n", rc);
3928 		spin_lock(&ses->ses_lock);
3929 		if (ses->ses_status == SES_IN_SETUP)
3930 			ses->ses_status = SES_NEED_RECON;
3931 		spin_lock(&ses->chan_lock);
3932 		cifs_chan_clear_in_reconnect(ses, server);
3933 		spin_unlock(&ses->chan_lock);
3934 		spin_unlock(&ses->ses_lock);
3935 	} else {
3936 		spin_lock(&ses->ses_lock);
3937 		if (ses->ses_status == SES_IN_SETUP)
3938 			ses->ses_status = SES_GOOD;
3939 		spin_lock(&ses->chan_lock);
3940 		cifs_chan_clear_in_reconnect(ses, server);
3941 		cifs_chan_clear_need_reconnect(ses, server);
3942 		spin_unlock(&ses->chan_lock);
3943 		spin_unlock(&ses->ses_lock);
3944 	}
3945 
3946 	return rc;
3947 }
3948 
3949 static int
3950 cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
3951 {
3952 	ctx->sectype = ses->sectype;
3953 
3954 	/* krb5 is special, since we don't need username or pw */
3955 	if (ctx->sectype == Kerberos)
3956 		return 0;
3957 
3958 	return cifs_set_cifscreds(ctx, ses);
3959 }
3960 
3961 static struct cifs_tcon *
3962 cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
3963 {
3964 	int rc;
3965 	struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
3966 	struct cifs_ses *ses;
3967 	struct cifs_tcon *tcon = NULL;
3968 	struct smb3_fs_context *ctx;
3969 
3970 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
3971 	if (ctx == NULL)
3972 		return ERR_PTR(-ENOMEM);
3973 
3974 	ctx->local_nls = cifs_sb->local_nls;
3975 	ctx->linux_uid = fsuid;
3976 	ctx->cred_uid = fsuid;
3977 	ctx->UNC = master_tcon->tree_name;
3978 	ctx->retry = master_tcon->retry;
3979 	ctx->nocase = master_tcon->nocase;
3980 	ctx->nohandlecache = master_tcon->nohandlecache;
3981 	ctx->local_lease = master_tcon->local_lease;
3982 	ctx->no_lease = master_tcon->no_lease;
3983 	ctx->resilient = master_tcon->use_resilient;
3984 	ctx->persistent = master_tcon->use_persistent;
3985 	ctx->handle_timeout = master_tcon->handle_timeout;
3986 	ctx->no_linux_ext = !master_tcon->unix_ext;
3987 	ctx->linux_ext = master_tcon->posix_extensions;
3988 	ctx->sectype = master_tcon->ses->sectype;
3989 	ctx->sign = master_tcon->ses->sign;
3990 	ctx->seal = master_tcon->seal;
3991 	ctx->witness = master_tcon->use_witness;
3992 
3993 	rc = cifs_set_vol_auth(ctx, master_tcon->ses);
3994 	if (rc) {
3995 		tcon = ERR_PTR(rc);
3996 		goto out;
3997 	}
3998 
3999 	/* get a reference for the same TCP session */
4000 	spin_lock(&cifs_tcp_ses_lock);
4001 	++master_tcon->ses->server->srv_count;
4002 	spin_unlock(&cifs_tcp_ses_lock);
4003 
4004 	ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
4005 	if (IS_ERR(ses)) {
4006 		tcon = (struct cifs_tcon *)ses;
4007 		cifs_put_tcp_session(master_tcon->ses->server, 0);
4008 		goto out;
4009 	}
4010 
4011 	tcon = cifs_get_tcon(ses, ctx);
4012 	if (IS_ERR(tcon)) {
4013 		cifs_put_smb_ses(ses);
4014 		goto out;
4015 	}
4016 
4017 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
4018 	if (cap_unix(ses))
4019 		reset_cifs_unix_caps(0, tcon, NULL, ctx);
4020 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
4021 
4022 out:
4023 	kfree(ctx->username);
4024 	kfree_sensitive(ctx->password);
4025 	kfree(ctx);
4026 
4027 	return tcon;
4028 }
4029 
4030 struct cifs_tcon *
4031 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
4032 {
4033 	return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
4034 }
4035 
4036 /* find and return a tlink with given uid */
4037 static struct tcon_link *
4038 tlink_rb_search(struct rb_root *root, kuid_t uid)
4039 {
4040 	struct rb_node *node = root->rb_node;
4041 	struct tcon_link *tlink;
4042 
4043 	while (node) {
4044 		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
4045 
4046 		if (uid_gt(tlink->tl_uid, uid))
4047 			node = node->rb_left;
4048 		else if (uid_lt(tlink->tl_uid, uid))
4049 			node = node->rb_right;
4050 		else
4051 			return tlink;
4052 	}
4053 	return NULL;
4054 }
4055 
4056 /* insert a tcon_link into the tree */
4057 static void
4058 tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
4059 {
4060 	struct rb_node **new = &(root->rb_node), *parent = NULL;
4061 	struct tcon_link *tlink;
4062 
4063 	while (*new) {
4064 		tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
4065 		parent = *new;
4066 
4067 		if (uid_gt(tlink->tl_uid, new_tlink->tl_uid))
4068 			new = &((*new)->rb_left);
4069 		else
4070 			new = &((*new)->rb_right);
4071 	}
4072 
4073 	rb_link_node(&new_tlink->tl_rbnode, parent, new);
4074 	rb_insert_color(&new_tlink->tl_rbnode, root);
4075 }
4076 
4077 /*
4078  * Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
4079  * current task.
4080  *
4081  * If the superblock doesn't refer to a multiuser mount, then just return
4082  * the master tcon for the mount.
4083  *
4084  * First, search the rbtree for an existing tcon for this fsuid. If one
4085  * exists, then check to see if it's pending construction. If it is then wait
4086  * for construction to complete. Once it's no longer pending, check to see if
4087  * it failed and either return an error or retry construction, depending on
4088  * the timeout.
4089  *
4090  * If one doesn't exist then insert a new tcon_link struct into the tree and
4091  * try to construct a new one.
4092  */
4093 struct tcon_link *
4094 cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
4095 {
4096 	int ret;
4097 	kuid_t fsuid = current_fsuid();
4098 	struct tcon_link *tlink, *newtlink;
4099 
4100 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
4101 		return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
4102 
4103 	spin_lock(&cifs_sb->tlink_tree_lock);
4104 	tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4105 	if (tlink)
4106 		cifs_get_tlink(tlink);
4107 	spin_unlock(&cifs_sb->tlink_tree_lock);
4108 
4109 	if (tlink == NULL) {
4110 		newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
4111 		if (newtlink == NULL)
4112 			return ERR_PTR(-ENOMEM);
4113 		newtlink->tl_uid = fsuid;
4114 		newtlink->tl_tcon = ERR_PTR(-EACCES);
4115 		set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
4116 		set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
4117 		cifs_get_tlink(newtlink);
4118 
4119 		spin_lock(&cifs_sb->tlink_tree_lock);
4120 		/* was one inserted after previous search? */
4121 		tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4122 		if (tlink) {
4123 			cifs_get_tlink(tlink);
4124 			spin_unlock(&cifs_sb->tlink_tree_lock);
4125 			kfree(newtlink);
4126 			goto wait_for_construction;
4127 		}
4128 		tlink = newtlink;
4129 		tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
4130 		spin_unlock(&cifs_sb->tlink_tree_lock);
4131 	} else {
4132 wait_for_construction:
4133 		ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
4134 				  TASK_INTERRUPTIBLE);
4135 		if (ret) {
4136 			cifs_put_tlink(tlink);
4137 			return ERR_PTR(-ERESTARTSYS);
4138 		}
4139 
4140 		/* if it's good, return it */
4141 		if (!IS_ERR(tlink->tl_tcon))
4142 			return tlink;
4143 
4144 		/* return error if we tried this already recently */
4145 		if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
4146 			cifs_put_tlink(tlink);
4147 			return ERR_PTR(-EACCES);
4148 		}
4149 
4150 		if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
4151 			goto wait_for_construction;
4152 	}
4153 
4154 	tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid);
4155 	clear_bit(TCON_LINK_PENDING, &tlink->tl_flags);
4156 	wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
4157 
4158 	if (IS_ERR(tlink->tl_tcon)) {
4159 		cifs_put_tlink(tlink);
4160 		return ERR_PTR(-EACCES);
4161 	}
4162 
4163 	return tlink;
4164 }
4165 
4166 /*
4167  * periodic workqueue job that scans tcon_tree for a superblock and closes
4168  * out tcons.
4169  */
4170 static void
4171 cifs_prune_tlinks(struct work_struct *work)
4172 {
4173 	struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
4174 						    prune_tlinks.work);
4175 	struct rb_root *root = &cifs_sb->tlink_tree;
4176 	struct rb_node *node;
4177 	struct rb_node *tmp;
4178 	struct tcon_link *tlink;
4179 
4180 	/*
4181 	 * Because we drop the spinlock in the loop in order to put the tlink
4182 	 * it's not guarded against removal of links from the tree. The only
4183 	 * places that remove entries from the tree are this function and
4184 	 * umounts. Because this function is non-reentrant and is canceled
4185 	 * before umount can proceed, this is safe.
4186 	 */
4187 	spin_lock(&cifs_sb->tlink_tree_lock);
4188 	node = rb_first(root);
4189 	while (node != NULL) {
4190 		tmp = node;
4191 		node = rb_next(tmp);
4192 		tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
4193 
4194 		if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
4195 		    atomic_read(&tlink->tl_count) != 0 ||
4196 		    time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
4197 			continue;
4198 
4199 		cifs_get_tlink(tlink);
4200 		clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
4201 		rb_erase(tmp, root);
4202 
4203 		spin_unlock(&cifs_sb->tlink_tree_lock);
4204 		cifs_put_tlink(tlink);
4205 		spin_lock(&cifs_sb->tlink_tree_lock);
4206 	}
4207 	spin_unlock(&cifs_sb->tlink_tree_lock);
4208 
4209 	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
4210 				TLINK_IDLE_EXPIRE);
4211 }
4212 
4213 #ifndef CONFIG_CIFS_DFS_UPCALL
4214 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4215 {
4216 	int rc;
4217 	const struct smb_version_operations *ops = tcon->ses->server->ops;
4218 
4219 	/* only send once per connect */
4220 	spin_lock(&tcon->tc_lock);
4221 	if (tcon->status == TID_GOOD) {
4222 		spin_unlock(&tcon->tc_lock);
4223 		return 0;
4224 	}
4225 
4226 	if (tcon->status != TID_NEW &&
4227 	    tcon->status != TID_NEED_TCON) {
4228 		spin_unlock(&tcon->tc_lock);
4229 		return -EHOSTDOWN;
4230 	}
4231 
4232 	tcon->status = TID_IN_TCON;
4233 	spin_unlock(&tcon->tc_lock);
4234 
4235 	rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon, nlsc);
4236 	if (rc) {
4237 		spin_lock(&tcon->tc_lock);
4238 		if (tcon->status == TID_IN_TCON)
4239 			tcon->status = TID_NEED_TCON;
4240 		spin_unlock(&tcon->tc_lock);
4241 	} else {
4242 		spin_lock(&tcon->tc_lock);
4243 		if (tcon->status == TID_IN_TCON)
4244 			tcon->status = TID_GOOD;
4245 		tcon->need_reconnect = false;
4246 		spin_unlock(&tcon->tc_lock);
4247 	}
4248 
4249 	return rc;
4250 }
4251 #endif
4252