xref: /linux/fs/smb/client/connect.c (revision 4e0373f1f920811a67fef0c3383f1ad602b3845e)
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 /* FIXME: should these be tunable? */
56 #define TLINK_ERROR_EXPIRE	(1 * HZ)
57 #define TLINK_IDLE_EXPIRE	(600 * HZ)
58 
59 /* Drop the connection to not overload the server */
60 #define MAX_STATUS_IO_TIMEOUT   5
61 
62 static int ip_connect(struct TCP_Server_Info *server);
63 static int generic_ip_connect(struct TCP_Server_Info *server);
64 static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
65 static void cifs_prune_tlinks(struct work_struct *work);
66 
67 /*
68  * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
69  * get their ip addresses changed at some point.
70  *
71  * This should be called with server->srv_mutex held.
72  */
73 static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
74 {
75 	int rc;
76 	int len;
77 	char *unc;
78 	struct sockaddr_storage ss;
79 
80 	if (!server->hostname)
81 		return -EINVAL;
82 
83 	/* if server hostname isn't populated, there's nothing to do here */
84 	if (server->hostname[0] == '\0')
85 		return 0;
86 
87 	len = strlen(server->hostname) + 3;
88 
89 	unc = kmalloc(len, GFP_KERNEL);
90 	if (!unc) {
91 		cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
92 		return -ENOMEM;
93 	}
94 	scnprintf(unc, len, "\\\\%s", server->hostname);
95 
96 	spin_lock(&server->srv_lock);
97 	ss = server->dstaddr;
98 	spin_unlock(&server->srv_lock);
99 
100 	rc = dns_resolve_server_name_to_ip(unc, (struct sockaddr *)&ss, NULL);
101 	kfree(unc);
102 
103 	if (rc < 0) {
104 		cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
105 			 __func__, server->hostname, rc);
106 	} else {
107 		spin_lock(&server->srv_lock);
108 		memcpy(&server->dstaddr, &ss, sizeof(server->dstaddr));
109 		spin_unlock(&server->srv_lock);
110 		rc = 0;
111 	}
112 
113 	return rc;
114 }
115 
116 static void smb2_query_server_interfaces(struct work_struct *work)
117 {
118 	int rc;
119 	int xid;
120 	struct cifs_tcon *tcon = container_of(work,
121 					struct cifs_tcon,
122 					query_interfaces.work);
123 	struct TCP_Server_Info *server = tcon->ses->server;
124 
125 	/*
126 	 * query server network interfaces, in case they change
127 	 */
128 	if (!server->ops->query_server_interfaces)
129 		return;
130 
131 	xid = get_xid();
132 	rc = server->ops->query_server_interfaces(xid, tcon, false);
133 	free_xid(xid);
134 
135 	if (rc) {
136 		if (rc == -EOPNOTSUPP)
137 			return;
138 
139 		cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
140 				__func__, rc);
141 	}
142 
143 	queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
144 			   (SMB_INTERFACE_POLL_INTERVAL * HZ));
145 }
146 
147 /*
148  * Update the tcpStatus for the server.
149  * This is used to signal the cifsd thread to call cifs_reconnect
150  * ONLY cifsd thread should call cifs_reconnect. For any other
151  * thread, use this function
152  *
153  * @server: the tcp ses for which reconnect is needed
154  * @all_channels: if this needs to be done for all channels
155  */
156 void
157 cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
158 				bool all_channels)
159 {
160 	struct TCP_Server_Info *pserver;
161 	struct cifs_ses *ses;
162 	int i;
163 
164 	/* If server is a channel, select the primary channel */
165 	pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
166 
167 	/* if we need to signal just this channel */
168 	if (!all_channels) {
169 		spin_lock(&server->srv_lock);
170 		if (server->tcpStatus != CifsExiting)
171 			server->tcpStatus = CifsNeedReconnect;
172 		spin_unlock(&server->srv_lock);
173 		return;
174 	}
175 
176 	spin_lock(&cifs_tcp_ses_lock);
177 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
178 		if (cifs_ses_exiting(ses))
179 			continue;
180 		spin_lock(&ses->chan_lock);
181 		for (i = 0; i < ses->chan_count; i++) {
182 			if (!ses->chans[i].server)
183 				continue;
184 
185 			spin_lock(&ses->chans[i].server->srv_lock);
186 			if (ses->chans[i].server->tcpStatus != CifsExiting)
187 				ses->chans[i].server->tcpStatus = CifsNeedReconnect;
188 			spin_unlock(&ses->chans[i].server->srv_lock);
189 		}
190 		spin_unlock(&ses->chan_lock);
191 	}
192 	spin_unlock(&cifs_tcp_ses_lock);
193 }
194 
195 /*
196  * Mark all sessions and tcons for reconnect.
197  * IMPORTANT: make sure that this gets called only from
198  * cifsd thread. For any other thread, use
199  * cifs_signal_cifsd_for_reconnect
200  *
201  * @server: the tcp ses for which reconnect is needed
202  * @server needs to be previously set to CifsNeedReconnect.
203  * @mark_smb_session: whether even sessions need to be marked
204  */
205 void
206 cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
207 				      bool mark_smb_session)
208 {
209 	struct TCP_Server_Info *pserver;
210 	struct cifs_ses *ses, *nses;
211 	struct cifs_tcon *tcon;
212 
213 	/*
214 	 * before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they
215 	 * are not used until reconnected.
216 	 */
217 	cifs_dbg(FYI, "%s: marking necessary sessions and tcons for reconnect\n", __func__);
218 
219 	/* If server is a channel, select the primary channel */
220 	pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
221 
222 	/*
223 	 * if the server has been marked for termination, there is a
224 	 * chance that the remaining channels all need reconnect. To be
225 	 * on the safer side, mark the session and trees for reconnect
226 	 * for this scenario. This might cause a few redundant session
227 	 * setup and tree connect requests, but it is better than not doing
228 	 * a tree connect when needed, and all following requests failing
229 	 */
230 	if (server->terminate) {
231 		mark_smb_session = true;
232 		server = pserver;
233 	}
234 
235 	spin_lock(&cifs_tcp_ses_lock);
236 	list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
237 		spin_lock(&ses->ses_lock);
238 		if (ses->ses_status == SES_EXITING) {
239 			spin_unlock(&ses->ses_lock);
240 			continue;
241 		}
242 		spin_unlock(&ses->ses_lock);
243 
244 		spin_lock(&ses->chan_lock);
245 		if (cifs_ses_get_chan_index(ses, server) ==
246 		    CIFS_INVAL_CHAN_INDEX) {
247 			spin_unlock(&ses->chan_lock);
248 			continue;
249 		}
250 
251 		if (!cifs_chan_is_iface_active(ses, server)) {
252 			spin_unlock(&ses->chan_lock);
253 			cifs_chan_update_iface(ses, server);
254 			spin_lock(&ses->chan_lock);
255 		}
256 
257 		if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server)) {
258 			spin_unlock(&ses->chan_lock);
259 			continue;
260 		}
261 
262 		if (mark_smb_session)
263 			CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses);
264 		else
265 			cifs_chan_set_need_reconnect(ses, server);
266 
267 		cifs_dbg(FYI, "%s: channel connect bitmap: 0x%lx\n",
268 			 __func__, ses->chans_need_reconnect);
269 
270 		/* If all channels need reconnect, then tcon needs reconnect */
271 		if (!mark_smb_session && !CIFS_ALL_CHANS_NEED_RECONNECT(ses)) {
272 			spin_unlock(&ses->chan_lock);
273 			continue;
274 		}
275 		spin_unlock(&ses->chan_lock);
276 
277 		spin_lock(&ses->ses_lock);
278 		ses->ses_status = SES_NEED_RECON;
279 		spin_unlock(&ses->ses_lock);
280 
281 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
282 			tcon->need_reconnect = true;
283 			spin_lock(&tcon->tc_lock);
284 			tcon->status = TID_NEED_RECON;
285 			spin_unlock(&tcon->tc_lock);
286 
287 			cancel_delayed_work(&tcon->query_interfaces);
288 		}
289 		if (ses->tcon_ipc) {
290 			ses->tcon_ipc->need_reconnect = true;
291 			spin_lock(&ses->tcon_ipc->tc_lock);
292 			ses->tcon_ipc->status = TID_NEED_RECON;
293 			spin_unlock(&ses->tcon_ipc->tc_lock);
294 		}
295 	}
296 	spin_unlock(&cifs_tcp_ses_lock);
297 }
298 
299 static void
300 cifs_abort_connection(struct TCP_Server_Info *server)
301 {
302 	struct mid_q_entry *mid, *nmid;
303 	struct list_head retry_list;
304 
305 	server->maxBuf = 0;
306 	server->max_read = 0;
307 
308 	/* do not want to be sending data on a socket we are freeing */
309 	cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
310 	cifs_server_lock(server);
311 	if (server->ssocket) {
312 		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
313 			 server->ssocket->flags);
314 		kernel_sock_shutdown(server->ssocket, SHUT_WR);
315 		cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n", server->ssocket->state,
316 			 server->ssocket->flags);
317 		sock_release(server->ssocket);
318 		server->ssocket = NULL;
319 	}
320 	server->sequence_number = 0;
321 	server->session_estab = false;
322 	kfree_sensitive(server->session_key.response);
323 	server->session_key.response = NULL;
324 	server->session_key.len = 0;
325 	server->lstrp = jiffies;
326 
327 	/* mark submitted MIDs for retry and issue callback */
328 	INIT_LIST_HEAD(&retry_list);
329 	cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
330 	spin_lock(&server->mid_lock);
331 	list_for_each_entry_safe(mid, nmid, &server->pending_mid_q, qhead) {
332 		kref_get(&mid->refcount);
333 		if (mid->mid_state == MID_REQUEST_SUBMITTED)
334 			mid->mid_state = MID_RETRY_NEEDED;
335 		list_move(&mid->qhead, &retry_list);
336 		mid->mid_flags |= MID_DELETED;
337 	}
338 	spin_unlock(&server->mid_lock);
339 	cifs_server_unlock(server);
340 
341 	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
342 	list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
343 		list_del_init(&mid->qhead);
344 		mid->callback(mid);
345 		release_mid(mid);
346 	}
347 
348 	if (cifs_rdma_enabled(server)) {
349 		cifs_server_lock(server);
350 		smbd_destroy(server);
351 		cifs_server_unlock(server);
352 	}
353 }
354 
355 static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
356 {
357 	spin_lock(&server->srv_lock);
358 	server->nr_targets = num_targets;
359 	if (server->tcpStatus == CifsExiting) {
360 		/* the demux thread will exit normally next time through the loop */
361 		spin_unlock(&server->srv_lock);
362 		wake_up(&server->response_q);
363 		return false;
364 	}
365 
366 	cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
367 	trace_smb3_reconnect(server->CurrentMid, server->conn_id,
368 			     server->hostname);
369 	server->tcpStatus = CifsNeedReconnect;
370 
371 	spin_unlock(&server->srv_lock);
372 	return true;
373 }
374 
375 /*
376  * cifs tcp session reconnection
377  *
378  * mark tcp session as reconnecting so temporarily locked
379  * mark all smb sessions as reconnecting for tcp session
380  * reconnect tcp session
381  * wake up waiters on reconnection? - (not needed currently)
382  *
383  * if mark_smb_session is passed as true, unconditionally mark
384  * the smb session (and tcon) for reconnect as well. This value
385  * doesn't really matter for non-multichannel scenario.
386  *
387  */
388 static int __cifs_reconnect(struct TCP_Server_Info *server,
389 			    bool mark_smb_session)
390 {
391 	int rc = 0;
392 
393 	if (!cifs_tcp_ses_needs_reconnect(server, 1))
394 		return 0;
395 
396 	cifs_mark_tcp_ses_conns_for_reconnect(server, mark_smb_session);
397 
398 	cifs_abort_connection(server);
399 
400 	do {
401 		try_to_freeze();
402 		cifs_server_lock(server);
403 
404 		if (!cifs_swn_set_server_dstaddr(server)) {
405 			/* resolve the hostname again to make sure that IP address is up-to-date */
406 			rc = reconn_set_ipaddr_from_hostname(server);
407 			cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
408 		}
409 
410 		if (cifs_rdma_enabled(server))
411 			rc = smbd_reconnect(server);
412 		else
413 			rc = generic_ip_connect(server);
414 		if (rc) {
415 			cifs_server_unlock(server);
416 			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
417 			msleep(3000);
418 		} else {
419 			atomic_inc(&tcpSesReconnectCount);
420 			set_credits(server, 1);
421 			spin_lock(&server->srv_lock);
422 			if (server->tcpStatus != CifsExiting)
423 				server->tcpStatus = CifsNeedNegotiate;
424 			spin_unlock(&server->srv_lock);
425 			cifs_swn_reset_server_dstaddr(server);
426 			cifs_server_unlock(server);
427 			mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
428 		}
429 	} while (server->tcpStatus == CifsNeedReconnect);
430 
431 	spin_lock(&server->srv_lock);
432 	if (server->tcpStatus == CifsNeedNegotiate)
433 		mod_delayed_work(cifsiod_wq, &server->echo, 0);
434 	spin_unlock(&server->srv_lock);
435 
436 	wake_up(&server->response_q);
437 	return rc;
438 }
439 
440 #ifdef CONFIG_CIFS_DFS_UPCALL
441 static int __reconnect_target_unlocked(struct TCP_Server_Info *server, const char *target)
442 {
443 	int rc;
444 	char *hostname;
445 
446 	if (!cifs_swn_set_server_dstaddr(server)) {
447 		if (server->hostname != target) {
448 			hostname = extract_hostname(target);
449 			if (!IS_ERR(hostname)) {
450 				spin_lock(&server->srv_lock);
451 				kfree(server->hostname);
452 				server->hostname = hostname;
453 				spin_unlock(&server->srv_lock);
454 			} else {
455 				cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
456 					 __func__, PTR_ERR(hostname));
457 				cifs_dbg(FYI, "%s: default to last target server: %s\n", __func__,
458 					 server->hostname);
459 			}
460 		}
461 		/* resolve the hostname again to make sure that IP address is up-to-date. */
462 		rc = reconn_set_ipaddr_from_hostname(server);
463 		cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
464 	}
465 	/* Reconnect the socket */
466 	if (cifs_rdma_enabled(server))
467 		rc = smbd_reconnect(server);
468 	else
469 		rc = generic_ip_connect(server);
470 
471 	return rc;
472 }
473 
474 static int reconnect_target_unlocked(struct TCP_Server_Info *server, struct dfs_cache_tgt_list *tl,
475 				     struct dfs_cache_tgt_iterator **target_hint)
476 {
477 	int rc;
478 	struct dfs_cache_tgt_iterator *tit;
479 
480 	*target_hint = NULL;
481 
482 	/* If dfs target list is empty, then reconnect to last server */
483 	tit = dfs_cache_get_tgt_iterator(tl);
484 	if (!tit)
485 		return __reconnect_target_unlocked(server, server->hostname);
486 
487 	/* Otherwise, try every dfs target in @tl */
488 	for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
489 		rc = __reconnect_target_unlocked(server, dfs_cache_get_tgt_name(tit));
490 		if (!rc) {
491 			*target_hint = tit;
492 			break;
493 		}
494 	}
495 	return rc;
496 }
497 
498 static int reconnect_dfs_server(struct TCP_Server_Info *server)
499 {
500 	struct dfs_cache_tgt_iterator *target_hint = NULL;
501 
502 	DFS_CACHE_TGT_LIST(tl);
503 	int num_targets = 0;
504 	int rc = 0;
505 
506 	/*
507 	 * Determine the number of dfs targets the referral path in @cifs_sb resolves to.
508 	 *
509 	 * smb2_reconnect() needs to know how long it should wait based upon the number of dfs
510 	 * targets (server->nr_targets).  It's also possible that the cached referral was cleared
511 	 * through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
512 	 * refreshing the referral, so, in this case, default it to 1.
513 	 */
514 	mutex_lock(&server->refpath_lock);
515 	if (!dfs_cache_noreq_find(server->leaf_fullpath + 1, NULL, &tl))
516 		num_targets = dfs_cache_get_nr_tgts(&tl);
517 	mutex_unlock(&server->refpath_lock);
518 	if (!num_targets)
519 		num_targets = 1;
520 
521 	if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
522 		return 0;
523 
524 	/*
525 	 * Unconditionally mark all sessions & tcons for reconnect as we might be connecting to a
526 	 * different server or share during failover.  It could be improved by adding some logic to
527 	 * only do that in case it connects to a different server or share, though.
528 	 */
529 	cifs_mark_tcp_ses_conns_for_reconnect(server, true);
530 
531 	cifs_abort_connection(server);
532 
533 	do {
534 		try_to_freeze();
535 		cifs_server_lock(server);
536 
537 		rc = reconnect_target_unlocked(server, &tl, &target_hint);
538 		if (rc) {
539 			/* Failed to reconnect socket */
540 			cifs_server_unlock(server);
541 			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
542 			msleep(3000);
543 			continue;
544 		}
545 		/*
546 		 * Socket was created.  Update tcp session status to CifsNeedNegotiate so that a
547 		 * process waiting for reconnect will know it needs to re-establish session and tcon
548 		 * through the reconnected target server.
549 		 */
550 		atomic_inc(&tcpSesReconnectCount);
551 		set_credits(server, 1);
552 		spin_lock(&server->srv_lock);
553 		if (server->tcpStatus != CifsExiting)
554 			server->tcpStatus = CifsNeedNegotiate;
555 		spin_unlock(&server->srv_lock);
556 		cifs_swn_reset_server_dstaddr(server);
557 		cifs_server_unlock(server);
558 		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
559 	} while (server->tcpStatus == CifsNeedReconnect);
560 
561 	mutex_lock(&server->refpath_lock);
562 	dfs_cache_noreq_update_tgthint(server->leaf_fullpath + 1, target_hint);
563 	mutex_unlock(&server->refpath_lock);
564 	dfs_cache_free_tgts(&tl);
565 
566 	/* Need to set up echo worker again once connection has been established */
567 	spin_lock(&server->srv_lock);
568 	if (server->tcpStatus == CifsNeedNegotiate)
569 		mod_delayed_work(cifsiod_wq, &server->echo, 0);
570 	spin_unlock(&server->srv_lock);
571 
572 	wake_up(&server->response_q);
573 	return rc;
574 }
575 
576 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
577 {
578 	mutex_lock(&server->refpath_lock);
579 	if (!server->leaf_fullpath) {
580 		mutex_unlock(&server->refpath_lock);
581 		return __cifs_reconnect(server, mark_smb_session);
582 	}
583 	mutex_unlock(&server->refpath_lock);
584 
585 	return reconnect_dfs_server(server);
586 }
587 #else
588 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
589 {
590 	return __cifs_reconnect(server, mark_smb_session);
591 }
592 #endif
593 
594 static void
595 cifs_echo_request(struct work_struct *work)
596 {
597 	int rc;
598 	struct TCP_Server_Info *server = container_of(work,
599 					struct TCP_Server_Info, echo.work);
600 
601 	/*
602 	 * We cannot send an echo if it is disabled.
603 	 * Also, no need to ping if we got a response recently.
604 	 */
605 
606 	if (server->tcpStatus == CifsNeedReconnect ||
607 	    server->tcpStatus == CifsExiting ||
608 	    server->tcpStatus == CifsNew ||
609 	    (server->ops->can_echo && !server->ops->can_echo(server)) ||
610 	    time_before(jiffies, server->lstrp + server->echo_interval - HZ))
611 		goto requeue_echo;
612 
613 	rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
614 	cifs_server_dbg(FYI, "send echo request: rc = %d\n", rc);
615 
616 	/* Check witness registrations */
617 	cifs_swn_check();
618 
619 requeue_echo:
620 	queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
621 }
622 
623 static bool
624 allocate_buffers(struct TCP_Server_Info *server)
625 {
626 	if (!server->bigbuf) {
627 		server->bigbuf = (char *)cifs_buf_get();
628 		if (!server->bigbuf) {
629 			cifs_server_dbg(VFS, "No memory for large SMB response\n");
630 			msleep(3000);
631 			/* retry will check if exiting */
632 			return false;
633 		}
634 	} else if (server->large_buf) {
635 		/* we are reusing a dirty large buf, clear its start */
636 		memset(server->bigbuf, 0, HEADER_SIZE(server));
637 	}
638 
639 	if (!server->smallbuf) {
640 		server->smallbuf = (char *)cifs_small_buf_get();
641 		if (!server->smallbuf) {
642 			cifs_server_dbg(VFS, "No memory for SMB response\n");
643 			msleep(1000);
644 			/* retry will check if exiting */
645 			return false;
646 		}
647 		/* beginning of smb buffer is cleared in our buf_get */
648 	} else {
649 		/* if existing small buf clear beginning */
650 		memset(server->smallbuf, 0, HEADER_SIZE(server));
651 	}
652 
653 	return true;
654 }
655 
656 static bool
657 server_unresponsive(struct TCP_Server_Info *server)
658 {
659 	/*
660 	 * If we're in the process of mounting a share or reconnecting a session
661 	 * and the server abruptly shut down (e.g. socket wasn't closed, packet
662 	 * had been ACK'ed but no SMB response), don't wait longer than 20s to
663 	 * negotiate protocol.
664 	 */
665 	spin_lock(&server->srv_lock);
666 	if (server->tcpStatus == CifsInNegotiate &&
667 	    time_after(jiffies, server->lstrp + 20 * HZ)) {
668 		spin_unlock(&server->srv_lock);
669 		cifs_reconnect(server, false);
670 		return true;
671 	}
672 	/*
673 	 * We need to wait 3 echo intervals to make sure we handle such
674 	 * situations right:
675 	 * 1s  client sends a normal SMB request
676 	 * 2s  client gets a response
677 	 * 30s echo workqueue job pops, and decides we got a response recently
678 	 *     and don't need to send another
679 	 * ...
680 	 * 65s kernel_recvmsg times out, and we see that we haven't gotten
681 	 *     a response in >60s.
682 	 */
683 	if ((server->tcpStatus == CifsGood ||
684 	    server->tcpStatus == CifsNeedNegotiate) &&
685 	    (!server->ops->can_echo || server->ops->can_echo(server)) &&
686 	    time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
687 		spin_unlock(&server->srv_lock);
688 		cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
689 			 (3 * server->echo_interval) / HZ);
690 		cifs_reconnect(server, false);
691 		return true;
692 	}
693 	spin_unlock(&server->srv_lock);
694 
695 	return false;
696 }
697 
698 static inline bool
699 zero_credits(struct TCP_Server_Info *server)
700 {
701 	int val;
702 
703 	spin_lock(&server->req_lock);
704 	val = server->credits + server->echo_credits + server->oplock_credits;
705 	if (server->in_flight == 0 && val == 0) {
706 		spin_unlock(&server->req_lock);
707 		return true;
708 	}
709 	spin_unlock(&server->req_lock);
710 	return false;
711 }
712 
713 static int
714 cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
715 {
716 	int length = 0;
717 	int total_read;
718 
719 	for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
720 		try_to_freeze();
721 
722 		/* reconnect if no credits and no requests in flight */
723 		if (zero_credits(server)) {
724 			cifs_reconnect(server, false);
725 			return -ECONNABORTED;
726 		}
727 
728 		if (server_unresponsive(server))
729 			return -ECONNABORTED;
730 		if (cifs_rdma_enabled(server) && server->smbd_conn)
731 			length = smbd_recv(server->smbd_conn, smb_msg);
732 		else
733 			length = sock_recvmsg(server->ssocket, smb_msg, 0);
734 
735 		spin_lock(&server->srv_lock);
736 		if (server->tcpStatus == CifsExiting) {
737 			spin_unlock(&server->srv_lock);
738 			return -ESHUTDOWN;
739 		}
740 
741 		if (server->tcpStatus == CifsNeedReconnect) {
742 			spin_unlock(&server->srv_lock);
743 			cifs_reconnect(server, false);
744 			return -ECONNABORTED;
745 		}
746 		spin_unlock(&server->srv_lock);
747 
748 		if (length == -ERESTARTSYS ||
749 		    length == -EAGAIN ||
750 		    length == -EINTR) {
751 			/*
752 			 * Minimum sleep to prevent looping, allowing socket
753 			 * to clear and app threads to set tcpStatus
754 			 * CifsNeedReconnect if server hung.
755 			 */
756 			usleep_range(1000, 2000);
757 			length = 0;
758 			continue;
759 		}
760 
761 		if (length <= 0) {
762 			cifs_dbg(FYI, "Received no data or error: %d\n", length);
763 			cifs_reconnect(server, false);
764 			return -ECONNABORTED;
765 		}
766 	}
767 	return total_read;
768 }
769 
770 int
771 cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
772 		      unsigned int to_read)
773 {
774 	struct msghdr smb_msg = {};
775 	struct kvec iov = {.iov_base = buf, .iov_len = to_read};
776 
777 	iov_iter_kvec(&smb_msg.msg_iter, ITER_DEST, &iov, 1, to_read);
778 
779 	return cifs_readv_from_socket(server, &smb_msg);
780 }
781 
782 ssize_t
783 cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
784 {
785 	struct msghdr smb_msg = {};
786 
787 	/*
788 	 *  iov_iter_discard already sets smb_msg.type and count and iov_offset
789 	 *  and cifs_readv_from_socket sets msg_control and msg_controllen
790 	 *  so little to initialize in struct msghdr
791 	 */
792 	iov_iter_discard(&smb_msg.msg_iter, ITER_DEST, to_read);
793 
794 	return cifs_readv_from_socket(server, &smb_msg);
795 }
796 
797 int
798 cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
799 	unsigned int page_offset, unsigned int to_read)
800 {
801 	struct msghdr smb_msg = {};
802 	struct bio_vec bv;
803 
804 	bvec_set_page(&bv, page, to_read, page_offset);
805 	iov_iter_bvec(&smb_msg.msg_iter, ITER_DEST, &bv, 1, to_read);
806 	return cifs_readv_from_socket(server, &smb_msg);
807 }
808 
809 int
810 cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter,
811 			   unsigned int to_read)
812 {
813 	struct msghdr smb_msg = { .msg_iter = *iter };
814 	int ret;
815 
816 	iov_iter_truncate(&smb_msg.msg_iter, to_read);
817 	ret = cifs_readv_from_socket(server, &smb_msg);
818 	if (ret > 0)
819 		iov_iter_advance(iter, ret);
820 	return ret;
821 }
822 
823 static bool
824 is_smb_response(struct TCP_Server_Info *server, unsigned char type)
825 {
826 	/*
827 	 * The first byte big endian of the length field,
828 	 * is actually not part of the length but the type
829 	 * with the most common, zero, as regular data.
830 	 */
831 	switch (type) {
832 	case RFC1002_SESSION_MESSAGE:
833 		/* Regular SMB response */
834 		return true;
835 	case RFC1002_SESSION_KEEP_ALIVE:
836 		cifs_dbg(FYI, "RFC 1002 session keep alive\n");
837 		break;
838 	case RFC1002_POSITIVE_SESSION_RESPONSE:
839 		cifs_dbg(FYI, "RFC 1002 positive session response\n");
840 		break;
841 	case RFC1002_NEGATIVE_SESSION_RESPONSE:
842 		/*
843 		 * We get this from Windows 98 instead of an error on
844 		 * SMB negprot response.
845 		 */
846 		cifs_dbg(FYI, "RFC 1002 negative session response\n");
847 		/* give server a second to clean up */
848 		msleep(1000);
849 		/*
850 		 * Always try 445 first on reconnect since we get NACK
851 		 * on some if we ever connected to port 139 (the NACK
852 		 * is since we do not begin with RFC1001 session
853 		 * initialize frame).
854 		 */
855 		cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
856 		cifs_reconnect(server, true);
857 		break;
858 	default:
859 		cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
860 		cifs_reconnect(server, true);
861 	}
862 
863 	return false;
864 }
865 
866 void
867 dequeue_mid(struct mid_q_entry *mid, bool malformed)
868 {
869 #ifdef CONFIG_CIFS_STATS2
870 	mid->when_received = jiffies;
871 #endif
872 	spin_lock(&mid->server->mid_lock);
873 	if (!malformed)
874 		mid->mid_state = MID_RESPONSE_RECEIVED;
875 	else
876 		mid->mid_state = MID_RESPONSE_MALFORMED;
877 	/*
878 	 * Trying to handle/dequeue a mid after the send_recv()
879 	 * function has finished processing it is a bug.
880 	 */
881 	if (mid->mid_flags & MID_DELETED) {
882 		spin_unlock(&mid->server->mid_lock);
883 		pr_warn_once("trying to dequeue a deleted mid\n");
884 	} else {
885 		list_del_init(&mid->qhead);
886 		mid->mid_flags |= MID_DELETED;
887 		spin_unlock(&mid->server->mid_lock);
888 	}
889 }
890 
891 static unsigned int
892 smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
893 {
894 	struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
895 
896 	/*
897 	 * SMB1 does not use credits.
898 	 */
899 	if (is_smb1(server))
900 		return 0;
901 
902 	return le16_to_cpu(shdr->CreditRequest);
903 }
904 
905 static void
906 handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
907 	   char *buf, int malformed)
908 {
909 	if (server->ops->check_trans2 &&
910 	    server->ops->check_trans2(mid, server, buf, malformed))
911 		return;
912 	mid->credits_received = smb2_get_credits_from_hdr(buf, server);
913 	mid->resp_buf = buf;
914 	mid->large_buf = server->large_buf;
915 	/* Was previous buf put in mpx struct for multi-rsp? */
916 	if (!mid->multiRsp) {
917 		/* smb buffer will be freed by user thread */
918 		if (server->large_buf)
919 			server->bigbuf = NULL;
920 		else
921 			server->smallbuf = NULL;
922 	}
923 	dequeue_mid(mid, malformed);
924 }
925 
926 int
927 cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required)
928 {
929 	bool srv_sign_required = server->sec_mode & server->vals->signing_required;
930 	bool srv_sign_enabled = server->sec_mode & server->vals->signing_enabled;
931 	bool mnt_sign_enabled;
932 
933 	/*
934 	 * Is signing required by mnt options? If not then check
935 	 * global_secflags to see if it is there.
936 	 */
937 	if (!mnt_sign_required)
938 		mnt_sign_required = ((global_secflags & CIFSSEC_MUST_SIGN) ==
939 						CIFSSEC_MUST_SIGN);
940 
941 	/*
942 	 * If signing is required then it's automatically enabled too,
943 	 * otherwise, check to see if the secflags allow it.
944 	 */
945 	mnt_sign_enabled = mnt_sign_required ? mnt_sign_required :
946 				(global_secflags & CIFSSEC_MAY_SIGN);
947 
948 	/* If server requires signing, does client allow it? */
949 	if (srv_sign_required) {
950 		if (!mnt_sign_enabled) {
951 			cifs_dbg(VFS, "Server requires signing, but it's disabled in SecurityFlags!\n");
952 			return -EOPNOTSUPP;
953 		}
954 		server->sign = true;
955 	}
956 
957 	/* If client requires signing, does server allow it? */
958 	if (mnt_sign_required) {
959 		if (!srv_sign_enabled) {
960 			cifs_dbg(VFS, "Server does not support signing!\n");
961 			return -EOPNOTSUPP;
962 		}
963 		server->sign = true;
964 	}
965 
966 	if (cifs_rdma_enabled(server) && server->sign)
967 		cifs_dbg(VFS, "Signing is enabled, and RDMA read/write will be disabled\n");
968 
969 	return 0;
970 }
971 
972 static noinline_for_stack void
973 clean_demultiplex_info(struct TCP_Server_Info *server)
974 {
975 	int length;
976 
977 	/* take it off the list, if it's not already */
978 	spin_lock(&server->srv_lock);
979 	list_del_init(&server->tcp_ses_list);
980 	spin_unlock(&server->srv_lock);
981 
982 	cancel_delayed_work_sync(&server->echo);
983 
984 	spin_lock(&server->srv_lock);
985 	server->tcpStatus = CifsExiting;
986 	spin_unlock(&server->srv_lock);
987 	wake_up_all(&server->response_q);
988 
989 	/* check if we have blocked requests that need to free */
990 	spin_lock(&server->req_lock);
991 	if (server->credits <= 0)
992 		server->credits = 1;
993 	spin_unlock(&server->req_lock);
994 	/*
995 	 * Although there should not be any requests blocked on this queue it
996 	 * can not hurt to be paranoid and try to wake up requests that may
997 	 * haven been blocked when more than 50 at time were on the wire to the
998 	 * same server - they now will see the session is in exit state and get
999 	 * out of SendReceive.
1000 	 */
1001 	wake_up_all(&server->request_q);
1002 	/* give those requests time to exit */
1003 	msleep(125);
1004 	if (cifs_rdma_enabled(server))
1005 		smbd_destroy(server);
1006 	if (server->ssocket) {
1007 		sock_release(server->ssocket);
1008 		server->ssocket = NULL;
1009 	}
1010 
1011 	if (!list_empty(&server->pending_mid_q)) {
1012 		struct mid_q_entry *mid_entry;
1013 		struct list_head *tmp, *tmp2;
1014 		LIST_HEAD(dispose_list);
1015 
1016 		spin_lock(&server->mid_lock);
1017 		list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
1018 			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
1019 			cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
1020 			kref_get(&mid_entry->refcount);
1021 			mid_entry->mid_state = MID_SHUTDOWN;
1022 			list_move(&mid_entry->qhead, &dispose_list);
1023 			mid_entry->mid_flags |= MID_DELETED;
1024 		}
1025 		spin_unlock(&server->mid_lock);
1026 
1027 		/* now walk dispose list and issue callbacks */
1028 		list_for_each_safe(tmp, tmp2, &dispose_list) {
1029 			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
1030 			cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
1031 			list_del_init(&mid_entry->qhead);
1032 			mid_entry->callback(mid_entry);
1033 			release_mid(mid_entry);
1034 		}
1035 		/* 1/8th of sec is more than enough time for them to exit */
1036 		msleep(125);
1037 	}
1038 
1039 	if (!list_empty(&server->pending_mid_q)) {
1040 		/*
1041 		 * mpx threads have not exited yet give them at least the smb
1042 		 * send timeout time for long ops.
1043 		 *
1044 		 * Due to delays on oplock break requests, we need to wait at
1045 		 * least 45 seconds before giving up on a request getting a
1046 		 * response and going ahead and killing cifsd.
1047 		 */
1048 		cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
1049 		msleep(46000);
1050 		/*
1051 		 * If threads still have not exited they are probably never
1052 		 * coming home not much else we can do but free the memory.
1053 		 */
1054 	}
1055 
1056 	kfree(server->leaf_fullpath);
1057 	kfree(server);
1058 
1059 	length = atomic_dec_return(&tcpSesAllocCount);
1060 	if (length > 0)
1061 		mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
1062 }
1063 
1064 static int
1065 standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
1066 {
1067 	int length;
1068 	char *buf = server->smallbuf;
1069 	unsigned int pdu_length = server->pdu_size;
1070 
1071 	/* make sure this will fit in a large buffer */
1072 	if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
1073 	    HEADER_PREAMBLE_SIZE(server)) {
1074 		cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
1075 		cifs_reconnect(server, true);
1076 		return -ECONNABORTED;
1077 	}
1078 
1079 	/* switch to large buffer if too big for a small one */
1080 	if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
1081 		server->large_buf = true;
1082 		memcpy(server->bigbuf, buf, server->total_read);
1083 		buf = server->bigbuf;
1084 	}
1085 
1086 	/* now read the rest */
1087 	length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
1088 				       pdu_length - MID_HEADER_SIZE(server));
1089 
1090 	if (length < 0)
1091 		return length;
1092 	server->total_read += length;
1093 
1094 	dump_smb(buf, server->total_read);
1095 
1096 	return cifs_handle_standard(server, mid);
1097 }
1098 
1099 int
1100 cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
1101 {
1102 	char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
1103 	int rc;
1104 
1105 	/*
1106 	 * We know that we received enough to get to the MID as we
1107 	 * checked the pdu_length earlier. Now check to see
1108 	 * if the rest of the header is OK.
1109 	 *
1110 	 * 48 bytes is enough to display the header and a little bit
1111 	 * into the payload for debugging purposes.
1112 	 */
1113 	rc = server->ops->check_message(buf, server->total_read, server);
1114 	if (rc)
1115 		cifs_dump_mem("Bad SMB: ", buf,
1116 			min_t(unsigned int, server->total_read, 48));
1117 
1118 	if (server->ops->is_session_expired &&
1119 	    server->ops->is_session_expired(buf)) {
1120 		cifs_reconnect(server, true);
1121 		return -1;
1122 	}
1123 
1124 	if (server->ops->is_status_pending &&
1125 	    server->ops->is_status_pending(buf, server))
1126 		return -1;
1127 
1128 	if (!mid)
1129 		return rc;
1130 
1131 	handle_mid(mid, server, buf, rc);
1132 	return 0;
1133 }
1134 
1135 static void
1136 smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
1137 {
1138 	struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
1139 	int scredits, in_flight;
1140 
1141 	/*
1142 	 * SMB1 does not use credits.
1143 	 */
1144 	if (is_smb1(server))
1145 		return;
1146 
1147 	if (shdr->CreditRequest) {
1148 		spin_lock(&server->req_lock);
1149 		server->credits += le16_to_cpu(shdr->CreditRequest);
1150 		scredits = server->credits;
1151 		in_flight = server->in_flight;
1152 		spin_unlock(&server->req_lock);
1153 		wake_up(&server->request_q);
1154 
1155 		trace_smb3_hdr_credits(server->CurrentMid,
1156 				server->conn_id, server->hostname, scredits,
1157 				le16_to_cpu(shdr->CreditRequest), in_flight);
1158 		cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
1159 				__func__, le16_to_cpu(shdr->CreditRequest),
1160 				scredits);
1161 	}
1162 }
1163 
1164 
1165 static int
1166 cifs_demultiplex_thread(void *p)
1167 {
1168 	int i, num_mids, length;
1169 	struct TCP_Server_Info *server = p;
1170 	unsigned int pdu_length;
1171 	unsigned int next_offset;
1172 	char *buf = NULL;
1173 	struct task_struct *task_to_wake = NULL;
1174 	struct mid_q_entry *mids[MAX_COMPOUND];
1175 	char *bufs[MAX_COMPOUND];
1176 	unsigned int noreclaim_flag, num_io_timeout = 0;
1177 	bool pending_reconnect = false;
1178 
1179 	noreclaim_flag = memalloc_noreclaim_save();
1180 	cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
1181 
1182 	length = atomic_inc_return(&tcpSesAllocCount);
1183 	if (length > 1)
1184 		mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
1185 
1186 	set_freezable();
1187 	allow_kernel_signal(SIGKILL);
1188 	while (server->tcpStatus != CifsExiting) {
1189 		if (try_to_freeze())
1190 			continue;
1191 
1192 		if (!allocate_buffers(server))
1193 			continue;
1194 
1195 		server->large_buf = false;
1196 		buf = server->smallbuf;
1197 		pdu_length = 4; /* enough to get RFC1001 header */
1198 
1199 		length = cifs_read_from_socket(server, buf, pdu_length);
1200 		if (length < 0)
1201 			continue;
1202 
1203 		if (is_smb1(server))
1204 			server->total_read = length;
1205 		else
1206 			server->total_read = 0;
1207 
1208 		/*
1209 		 * The right amount was read from socket - 4 bytes,
1210 		 * so we can now interpret the length field.
1211 		 */
1212 		pdu_length = get_rfc1002_length(buf);
1213 
1214 		cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
1215 		if (!is_smb_response(server, buf[0]))
1216 			continue;
1217 
1218 		pending_reconnect = false;
1219 next_pdu:
1220 		server->pdu_size = pdu_length;
1221 
1222 		/* make sure we have enough to get to the MID */
1223 		if (server->pdu_size < MID_HEADER_SIZE(server)) {
1224 			cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
1225 				 server->pdu_size);
1226 			cifs_reconnect(server, true);
1227 			continue;
1228 		}
1229 
1230 		/* read down to the MID */
1231 		length = cifs_read_from_socket(server,
1232 			     buf + HEADER_PREAMBLE_SIZE(server),
1233 			     MID_HEADER_SIZE(server));
1234 		if (length < 0)
1235 			continue;
1236 		server->total_read += length;
1237 
1238 		if (server->ops->next_header) {
1239 			if (server->ops->next_header(server, buf, &next_offset)) {
1240 				cifs_dbg(VFS, "%s: malformed response (next_offset=%u)\n",
1241 					 __func__, next_offset);
1242 				cifs_reconnect(server, true);
1243 				continue;
1244 			}
1245 			if (next_offset)
1246 				server->pdu_size = next_offset;
1247 		}
1248 
1249 		memset(mids, 0, sizeof(mids));
1250 		memset(bufs, 0, sizeof(bufs));
1251 		num_mids = 0;
1252 
1253 		if (server->ops->is_transform_hdr &&
1254 		    server->ops->receive_transform &&
1255 		    server->ops->is_transform_hdr(buf)) {
1256 			length = server->ops->receive_transform(server,
1257 								mids,
1258 								bufs,
1259 								&num_mids);
1260 		} else {
1261 			mids[0] = server->ops->find_mid(server, buf);
1262 			bufs[0] = buf;
1263 			num_mids = 1;
1264 
1265 			if (!mids[0] || !mids[0]->receive)
1266 				length = standard_receive3(server, mids[0]);
1267 			else
1268 				length = mids[0]->receive(server, mids[0]);
1269 		}
1270 
1271 		if (length < 0) {
1272 			for (i = 0; i < num_mids; i++)
1273 				if (mids[i])
1274 					release_mid(mids[i]);
1275 			continue;
1276 		}
1277 
1278 		if (server->ops->is_status_io_timeout &&
1279 		    server->ops->is_status_io_timeout(buf)) {
1280 			num_io_timeout++;
1281 			if (num_io_timeout > MAX_STATUS_IO_TIMEOUT) {
1282 				cifs_server_dbg(VFS,
1283 						"Number of request timeouts exceeded %d. Reconnecting",
1284 						MAX_STATUS_IO_TIMEOUT);
1285 
1286 				pending_reconnect = true;
1287 				num_io_timeout = 0;
1288 			}
1289 		}
1290 
1291 		server->lstrp = jiffies;
1292 
1293 		for (i = 0; i < num_mids; i++) {
1294 			if (mids[i] != NULL) {
1295 				mids[i]->resp_buf_size = server->pdu_size;
1296 
1297 				if (bufs[i] != NULL) {
1298 					if (server->ops->is_network_name_deleted &&
1299 					    server->ops->is_network_name_deleted(bufs[i],
1300 										 server)) {
1301 						cifs_server_dbg(FYI,
1302 								"Share deleted. Reconnect needed");
1303 					}
1304 				}
1305 
1306 				if (!mids[i]->multiRsp || mids[i]->multiEnd)
1307 					mids[i]->callback(mids[i]);
1308 
1309 				release_mid(mids[i]);
1310 			} else if (server->ops->is_oplock_break &&
1311 				   server->ops->is_oplock_break(bufs[i],
1312 								server)) {
1313 				smb2_add_credits_from_hdr(bufs[i], server);
1314 				cifs_dbg(FYI, "Received oplock break\n");
1315 			} else {
1316 				cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
1317 						atomic_read(&mid_count));
1318 				cifs_dump_mem("Received Data is: ", bufs[i],
1319 					      HEADER_SIZE(server));
1320 				smb2_add_credits_from_hdr(bufs[i], server);
1321 #ifdef CONFIG_CIFS_DEBUG2
1322 				if (server->ops->dump_detail)
1323 					server->ops->dump_detail(bufs[i],
1324 								 server);
1325 				cifs_dump_mids(server);
1326 #endif /* CIFS_DEBUG2 */
1327 			}
1328 		}
1329 
1330 		if (pdu_length > server->pdu_size) {
1331 			if (!allocate_buffers(server))
1332 				continue;
1333 			pdu_length -= server->pdu_size;
1334 			server->total_read = 0;
1335 			server->large_buf = false;
1336 			buf = server->smallbuf;
1337 			goto next_pdu;
1338 		}
1339 
1340 		/* do this reconnect at the very end after processing all MIDs */
1341 		if (pending_reconnect)
1342 			cifs_reconnect(server, true);
1343 
1344 	} /* end while !EXITING */
1345 
1346 	/* buffer usually freed in free_mid - need to free it here on exit */
1347 	cifs_buf_release(server->bigbuf);
1348 	if (server->smallbuf) /* no sense logging a debug message if NULL */
1349 		cifs_small_buf_release(server->smallbuf);
1350 
1351 	task_to_wake = xchg(&server->tsk, NULL);
1352 	clean_demultiplex_info(server);
1353 
1354 	/* if server->tsk was NULL then wait for a signal before exiting */
1355 	if (!task_to_wake) {
1356 		set_current_state(TASK_INTERRUPTIBLE);
1357 		while (!signal_pending(current)) {
1358 			schedule();
1359 			set_current_state(TASK_INTERRUPTIBLE);
1360 		}
1361 		set_current_state(TASK_RUNNING);
1362 	}
1363 
1364 	memalloc_noreclaim_restore(noreclaim_flag);
1365 	module_put_and_kthread_exit(0);
1366 }
1367 
1368 int
1369 cifs_ipaddr_cmp(struct sockaddr *srcaddr, struct sockaddr *rhs)
1370 {
1371 	struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1372 	struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1373 	struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1374 	struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1375 
1376 	switch (srcaddr->sa_family) {
1377 	case AF_UNSPEC:
1378 		switch (rhs->sa_family) {
1379 		case AF_UNSPEC:
1380 			return 0;
1381 		case AF_INET:
1382 		case AF_INET6:
1383 			return 1;
1384 		default:
1385 			return -1;
1386 		}
1387 	case AF_INET: {
1388 		switch (rhs->sa_family) {
1389 		case AF_UNSPEC:
1390 			return -1;
1391 		case AF_INET:
1392 			return memcmp(saddr4, vaddr4,
1393 				      sizeof(struct sockaddr_in));
1394 		case AF_INET6:
1395 			return 1;
1396 		default:
1397 			return -1;
1398 		}
1399 	}
1400 	case AF_INET6: {
1401 		switch (rhs->sa_family) {
1402 		case AF_UNSPEC:
1403 		case AF_INET:
1404 			return -1;
1405 		case AF_INET6:
1406 			return memcmp(saddr6,
1407 				      vaddr6,
1408 				      sizeof(struct sockaddr_in6));
1409 		default:
1410 			return -1;
1411 		}
1412 	}
1413 	default:
1414 		return -1; /* don't expect to be here */
1415 	}
1416 }
1417 
1418 /*
1419  * Returns true if srcaddr isn't specified and rhs isn't specified, or
1420  * if srcaddr is specified and matches the IP address of the rhs argument
1421  */
1422 bool
1423 cifs_match_ipaddr(struct sockaddr *srcaddr, struct sockaddr *rhs)
1424 {
1425 	switch (srcaddr->sa_family) {
1426 	case AF_UNSPEC:
1427 		return (rhs->sa_family == AF_UNSPEC);
1428 	case AF_INET: {
1429 		struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1430 		struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1431 
1432 		return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
1433 	}
1434 	case AF_INET6: {
1435 		struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1436 		struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1437 
1438 		return (ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr)
1439 			&& saddr6->sin6_scope_id == vaddr6->sin6_scope_id);
1440 	}
1441 	default:
1442 		WARN_ON(1);
1443 		return false; /* don't expect to be here */
1444 	}
1445 }
1446 
1447 /*
1448  * If no port is specified in addr structure, we try to match with 445 port
1449  * and if it fails - with 139 ports. It should be called only if address
1450  * families of server and addr are equal.
1451  */
1452 static bool
1453 match_port(struct TCP_Server_Info *server, struct sockaddr *addr)
1454 {
1455 	__be16 port, *sport;
1456 
1457 	/* SMBDirect manages its own ports, don't match it here */
1458 	if (server->rdma)
1459 		return true;
1460 
1461 	switch (addr->sa_family) {
1462 	case AF_INET:
1463 		sport = &((struct sockaddr_in *) &server->dstaddr)->sin_port;
1464 		port = ((struct sockaddr_in *) addr)->sin_port;
1465 		break;
1466 	case AF_INET6:
1467 		sport = &((struct sockaddr_in6 *) &server->dstaddr)->sin6_port;
1468 		port = ((struct sockaddr_in6 *) addr)->sin6_port;
1469 		break;
1470 	default:
1471 		WARN_ON(1);
1472 		return false;
1473 	}
1474 
1475 	if (!port) {
1476 		port = htons(CIFS_PORT);
1477 		if (port == *sport)
1478 			return true;
1479 
1480 		port = htons(RFC1001_PORT);
1481 	}
1482 
1483 	return port == *sport;
1484 }
1485 
1486 static bool match_server_address(struct TCP_Server_Info *server, struct sockaddr *addr)
1487 {
1488 	if (!cifs_match_ipaddr(addr, (struct sockaddr *)&server->dstaddr))
1489 		return false;
1490 
1491 	return true;
1492 }
1493 
1494 static bool
1495 match_security(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1496 {
1497 	/*
1498 	 * The select_sectype function should either return the ctx->sectype
1499 	 * that was specified, or "Unspecified" if that sectype was not
1500 	 * compatible with the given NEGOTIATE request.
1501 	 */
1502 	if (server->ops->select_sectype(server, ctx->sectype)
1503 	     == Unspecified)
1504 		return false;
1505 
1506 	/*
1507 	 * Now check if signing mode is acceptable. No need to check
1508 	 * global_secflags at this point since if MUST_SIGN is set then
1509 	 * the server->sign had better be too.
1510 	 */
1511 	if (ctx->sign && !server->sign)
1512 		return false;
1513 
1514 	return true;
1515 }
1516 
1517 /* this function must be called with srv_lock held */
1518 static int match_server(struct TCP_Server_Info *server,
1519 			struct smb3_fs_context *ctx,
1520 			bool match_super)
1521 {
1522 	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
1523 
1524 	lockdep_assert_held(&server->srv_lock);
1525 
1526 	if (ctx->nosharesock)
1527 		return 0;
1528 
1529 	/* this server does not share socket */
1530 	if (server->nosharesock)
1531 		return 0;
1532 
1533 	/* If multidialect negotiation see if existing sessions match one */
1534 	if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
1535 		if (server->vals->protocol_id < SMB30_PROT_ID)
1536 			return 0;
1537 	} else if (strcmp(ctx->vals->version_string,
1538 		   SMBDEFAULT_VERSION_STRING) == 0) {
1539 		if (server->vals->protocol_id < SMB21_PROT_ID)
1540 			return 0;
1541 	} else if ((server->vals != ctx->vals) || (server->ops != ctx->ops))
1542 		return 0;
1543 
1544 	if (!net_eq(cifs_net_ns(server), current->nsproxy->net_ns))
1545 		return 0;
1546 
1547 	if (!cifs_match_ipaddr((struct sockaddr *)&ctx->srcaddr,
1548 			       (struct sockaddr *)&server->srcaddr))
1549 		return 0;
1550 	/*
1551 	 * When matching cifs.ko superblocks (@match_super == true), we can't
1552 	 * really match either @server->leaf_fullpath or @server->dstaddr
1553 	 * directly since this @server might belong to a completely different
1554 	 * server -- in case of domain-based DFS referrals or DFS links -- as
1555 	 * provided earlier by mount(2) through 'source' and 'ip' options.
1556 	 *
1557 	 * Otherwise, match the DFS referral in @server->leaf_fullpath or the
1558 	 * destination address in @server->dstaddr.
1559 	 *
1560 	 * When using 'nodfs' mount option, we avoid sharing it with DFS
1561 	 * connections as they might failover.
1562 	 */
1563 	if (!match_super) {
1564 		if (!ctx->nodfs) {
1565 			if (server->leaf_fullpath) {
1566 				if (!ctx->leaf_fullpath ||
1567 				    strcasecmp(server->leaf_fullpath,
1568 					       ctx->leaf_fullpath))
1569 					return 0;
1570 			} else if (ctx->leaf_fullpath) {
1571 				return 0;
1572 			}
1573 		} else if (server->leaf_fullpath) {
1574 			return 0;
1575 		}
1576 	}
1577 
1578 	/*
1579 	 * Match for a regular connection (address/hostname/port) which has no
1580 	 * DFS referrals set.
1581 	 */
1582 	if (!server->leaf_fullpath &&
1583 	    (strcasecmp(server->hostname, ctx->server_hostname) ||
1584 	     !match_server_address(server, addr) ||
1585 	     !match_port(server, addr)))
1586 		return 0;
1587 
1588 	if (!match_security(server, ctx))
1589 		return 0;
1590 
1591 	if (server->echo_interval != ctx->echo_interval * HZ)
1592 		return 0;
1593 
1594 	if (server->rdma != ctx->rdma)
1595 		return 0;
1596 
1597 	if (server->ignore_signature != ctx->ignore_signature)
1598 		return 0;
1599 
1600 	if (server->min_offload != ctx->min_offload)
1601 		return 0;
1602 
1603 	if (server->retrans != ctx->retrans)
1604 		return 0;
1605 
1606 	return 1;
1607 }
1608 
1609 struct TCP_Server_Info *
1610 cifs_find_tcp_session(struct smb3_fs_context *ctx)
1611 {
1612 	struct TCP_Server_Info *server;
1613 
1614 	spin_lock(&cifs_tcp_ses_lock);
1615 	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
1616 		spin_lock(&server->srv_lock);
1617 		/*
1618 		 * Skip ses channels since they're only handled in lower layers
1619 		 * (e.g. cifs_send_recv).
1620 		 */
1621 		if (SERVER_IS_CHAN(server) ||
1622 		    !match_server(server, ctx, false)) {
1623 			spin_unlock(&server->srv_lock);
1624 			continue;
1625 		}
1626 		spin_unlock(&server->srv_lock);
1627 
1628 		++server->srv_count;
1629 		spin_unlock(&cifs_tcp_ses_lock);
1630 		cifs_dbg(FYI, "Existing tcp session with server found\n");
1631 		return server;
1632 	}
1633 	spin_unlock(&cifs_tcp_ses_lock);
1634 	return NULL;
1635 }
1636 
1637 void
1638 cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
1639 {
1640 	struct task_struct *task;
1641 
1642 	spin_lock(&cifs_tcp_ses_lock);
1643 	if (--server->srv_count > 0) {
1644 		spin_unlock(&cifs_tcp_ses_lock);
1645 		return;
1646 	}
1647 
1648 	/* srv_count can never go negative */
1649 	WARN_ON(server->srv_count < 0);
1650 
1651 	put_net(cifs_net_ns(server));
1652 
1653 	list_del_init(&server->tcp_ses_list);
1654 	spin_unlock(&cifs_tcp_ses_lock);
1655 
1656 	cancel_delayed_work_sync(&server->echo);
1657 
1658 	if (from_reconnect)
1659 		/*
1660 		 * Avoid deadlock here: reconnect work calls
1661 		 * cifs_put_tcp_session() at its end. Need to be sure
1662 		 * that reconnect work does nothing with server pointer after
1663 		 * that step.
1664 		 */
1665 		cancel_delayed_work(&server->reconnect);
1666 	else
1667 		cancel_delayed_work_sync(&server->reconnect);
1668 
1669 	/* For secondary channels, we pick up ref-count on the primary server */
1670 	if (SERVER_IS_CHAN(server))
1671 		cifs_put_tcp_session(server->primary_server, from_reconnect);
1672 
1673 	spin_lock(&server->srv_lock);
1674 	server->tcpStatus = CifsExiting;
1675 	spin_unlock(&server->srv_lock);
1676 
1677 	cifs_crypto_secmech_release(server);
1678 
1679 	kfree_sensitive(server->session_key.response);
1680 	server->session_key.response = NULL;
1681 	server->session_key.len = 0;
1682 	kfree(server->hostname);
1683 	server->hostname = NULL;
1684 
1685 	task = xchg(&server->tsk, NULL);
1686 	if (task)
1687 		send_sig(SIGKILL, task, 1);
1688 }
1689 
1690 struct TCP_Server_Info *
1691 cifs_get_tcp_session(struct smb3_fs_context *ctx,
1692 		     struct TCP_Server_Info *primary_server)
1693 {
1694 	struct TCP_Server_Info *tcp_ses = NULL;
1695 	int rc;
1696 
1697 	cifs_dbg(FYI, "UNC: %s\n", ctx->UNC);
1698 
1699 	/* see if we already have a matching tcp_ses */
1700 	tcp_ses = cifs_find_tcp_session(ctx);
1701 	if (tcp_ses)
1702 		return tcp_ses;
1703 
1704 	tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
1705 	if (!tcp_ses) {
1706 		rc = -ENOMEM;
1707 		goto out_err;
1708 	}
1709 
1710 	tcp_ses->hostname = kstrdup(ctx->server_hostname, GFP_KERNEL);
1711 	if (!tcp_ses->hostname) {
1712 		rc = -ENOMEM;
1713 		goto out_err;
1714 	}
1715 
1716 	if (ctx->leaf_fullpath) {
1717 		tcp_ses->leaf_fullpath = kstrdup(ctx->leaf_fullpath, GFP_KERNEL);
1718 		if (!tcp_ses->leaf_fullpath) {
1719 			rc = -ENOMEM;
1720 			goto out_err;
1721 		}
1722 	}
1723 
1724 	if (ctx->nosharesock)
1725 		tcp_ses->nosharesock = true;
1726 
1727 	tcp_ses->ops = ctx->ops;
1728 	tcp_ses->vals = ctx->vals;
1729 	cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
1730 
1731 	tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);
1732 	tcp_ses->noblockcnt = ctx->rootfs;
1733 	tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;
1734 	tcp_ses->noautotune = ctx->noautotune;
1735 	tcp_ses->tcp_nodelay = ctx->sockopt_tcp_nodelay;
1736 	tcp_ses->rdma = ctx->rdma;
1737 	tcp_ses->in_flight = 0;
1738 	tcp_ses->max_in_flight = 0;
1739 	tcp_ses->credits = 1;
1740 	if (primary_server) {
1741 		spin_lock(&cifs_tcp_ses_lock);
1742 		++primary_server->srv_count;
1743 		spin_unlock(&cifs_tcp_ses_lock);
1744 		tcp_ses->primary_server = primary_server;
1745 	}
1746 	init_waitqueue_head(&tcp_ses->response_q);
1747 	init_waitqueue_head(&tcp_ses->request_q);
1748 	INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
1749 	mutex_init(&tcp_ses->_srv_mutex);
1750 	memcpy(tcp_ses->workstation_RFC1001_name,
1751 		ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1752 	memcpy(tcp_ses->server_RFC1001_name,
1753 		ctx->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1754 	tcp_ses->session_estab = false;
1755 	tcp_ses->sequence_number = 0;
1756 	tcp_ses->channel_sequence_num = 0; /* only tracked for primary channel */
1757 	tcp_ses->reconnect_instance = 1;
1758 	tcp_ses->lstrp = jiffies;
1759 	tcp_ses->compression.requested = ctx->compress;
1760 	spin_lock_init(&tcp_ses->req_lock);
1761 	spin_lock_init(&tcp_ses->srv_lock);
1762 	spin_lock_init(&tcp_ses->mid_lock);
1763 	INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
1764 	INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
1765 	INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
1766 	INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
1767 	mutex_init(&tcp_ses->reconnect_mutex);
1768 #ifdef CONFIG_CIFS_DFS_UPCALL
1769 	mutex_init(&tcp_ses->refpath_lock);
1770 #endif
1771 	memcpy(&tcp_ses->srcaddr, &ctx->srcaddr,
1772 	       sizeof(tcp_ses->srcaddr));
1773 	memcpy(&tcp_ses->dstaddr, &ctx->dstaddr,
1774 		sizeof(tcp_ses->dstaddr));
1775 	if (ctx->use_client_guid)
1776 		memcpy(tcp_ses->client_guid, ctx->client_guid,
1777 		       SMB2_CLIENT_GUID_SIZE);
1778 	else
1779 		generate_random_uuid(tcp_ses->client_guid);
1780 	/*
1781 	 * at this point we are the only ones with the pointer
1782 	 * to the struct since the kernel thread not created yet
1783 	 * no need to spinlock this init of tcpStatus or srv_count
1784 	 */
1785 	tcp_ses->tcpStatus = CifsNew;
1786 	++tcp_ses->srv_count;
1787 
1788 	if (ctx->echo_interval >= SMB_ECHO_INTERVAL_MIN &&
1789 		ctx->echo_interval <= SMB_ECHO_INTERVAL_MAX)
1790 		tcp_ses->echo_interval = ctx->echo_interval * HZ;
1791 	else
1792 		tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
1793 	if (tcp_ses->rdma) {
1794 #ifndef CONFIG_CIFS_SMB_DIRECT
1795 		cifs_dbg(VFS, "CONFIG_CIFS_SMB_DIRECT is not enabled\n");
1796 		rc = -ENOENT;
1797 		goto out_err_crypto_release;
1798 #endif
1799 		tcp_ses->smbd_conn = smbd_get_connection(
1800 			tcp_ses, (struct sockaddr *)&ctx->dstaddr);
1801 		if (tcp_ses->smbd_conn) {
1802 			cifs_dbg(VFS, "RDMA transport established\n");
1803 			rc = 0;
1804 			goto smbd_connected;
1805 		} else {
1806 			rc = -ENOENT;
1807 			goto out_err_crypto_release;
1808 		}
1809 	}
1810 	rc = ip_connect(tcp_ses);
1811 	if (rc < 0) {
1812 		cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
1813 		goto out_err_crypto_release;
1814 	}
1815 smbd_connected:
1816 	/*
1817 	 * since we're in a cifs function already, we know that
1818 	 * this will succeed. No need for try_module_get().
1819 	 */
1820 	__module_get(THIS_MODULE);
1821 	tcp_ses->tsk = kthread_run(cifs_demultiplex_thread,
1822 				  tcp_ses, "cifsd");
1823 	if (IS_ERR(tcp_ses->tsk)) {
1824 		rc = PTR_ERR(tcp_ses->tsk);
1825 		cifs_dbg(VFS, "error %d create cifsd thread\n", rc);
1826 		module_put(THIS_MODULE);
1827 		goto out_err_crypto_release;
1828 	}
1829 	tcp_ses->min_offload = ctx->min_offload;
1830 	tcp_ses->retrans = ctx->retrans;
1831 	/*
1832 	 * at this point we are the only ones with the pointer
1833 	 * to the struct since the kernel thread not created yet
1834 	 * no need to spinlock this update of tcpStatus
1835 	 */
1836 	spin_lock(&tcp_ses->srv_lock);
1837 	tcp_ses->tcpStatus = CifsNeedNegotiate;
1838 	spin_unlock(&tcp_ses->srv_lock);
1839 
1840 	if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
1841 		tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
1842 	else
1843 		tcp_ses->max_credits = ctx->max_credits;
1844 
1845 	tcp_ses->nr_targets = 1;
1846 	tcp_ses->ignore_signature = ctx->ignore_signature;
1847 	/* thread spawned, put it on the list */
1848 	spin_lock(&cifs_tcp_ses_lock);
1849 	list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
1850 	spin_unlock(&cifs_tcp_ses_lock);
1851 
1852 	/* queue echo request delayed work */
1853 	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
1854 
1855 	return tcp_ses;
1856 
1857 out_err_crypto_release:
1858 	cifs_crypto_secmech_release(tcp_ses);
1859 
1860 	put_net(cifs_net_ns(tcp_ses));
1861 
1862 out_err:
1863 	if (tcp_ses) {
1864 		if (SERVER_IS_CHAN(tcp_ses))
1865 			cifs_put_tcp_session(tcp_ses->primary_server, false);
1866 		kfree(tcp_ses->hostname);
1867 		kfree(tcp_ses->leaf_fullpath);
1868 		if (tcp_ses->ssocket)
1869 			sock_release(tcp_ses->ssocket);
1870 		kfree(tcp_ses);
1871 	}
1872 	return ERR_PTR(rc);
1873 }
1874 
1875 /* this function must be called with ses_lock and chan_lock held */
1876 static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1877 {
1878 	if (ctx->sectype != Unspecified &&
1879 	    ctx->sectype != ses->sectype)
1880 		return 0;
1881 
1882 	if (ctx->dfs_root_ses != ses->dfs_root_ses)
1883 		return 0;
1884 
1885 	/*
1886 	 * If an existing session is limited to less channels than
1887 	 * requested, it should not be reused
1888 	 */
1889 	if (ses->chan_max < ctx->max_channels)
1890 		return 0;
1891 
1892 	switch (ses->sectype) {
1893 	case Kerberos:
1894 		if (!uid_eq(ctx->cred_uid, ses->cred_uid))
1895 			return 0;
1896 		break;
1897 	default:
1898 		/* NULL username means anonymous session */
1899 		if (ses->user_name == NULL) {
1900 			if (!ctx->nullauth)
1901 				return 0;
1902 			break;
1903 		}
1904 
1905 		/* anything else takes username/password */
1906 		if (strncmp(ses->user_name,
1907 			    ctx->username ? ctx->username : "",
1908 			    CIFS_MAX_USERNAME_LEN))
1909 			return 0;
1910 		if ((ctx->username && strlen(ctx->username) != 0) &&
1911 		    ses->password != NULL &&
1912 		    strncmp(ses->password,
1913 			    ctx->password ? ctx->password : "",
1914 			    CIFS_MAX_PASSWORD_LEN))
1915 			return 0;
1916 	}
1917 
1918 	if (strcmp(ctx->local_nls->charset, ses->local_nls->charset))
1919 		return 0;
1920 
1921 	return 1;
1922 }
1923 
1924 /**
1925  * cifs_setup_ipc - helper to setup the IPC tcon for the session
1926  * @ses: smb session to issue the request on
1927  * @ctx: the superblock configuration context to use for building the
1928  *       new tree connection for the IPC (interprocess communication RPC)
1929  *
1930  * A new IPC connection is made and stored in the session
1931  * tcon_ipc. The IPC tcon has the same lifetime as the session.
1932  */
1933 static int
1934 cifs_setup_ipc(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1935 {
1936 	int rc = 0, xid;
1937 	struct cifs_tcon *tcon;
1938 	char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
1939 	bool seal = false;
1940 	struct TCP_Server_Info *server = ses->server;
1941 
1942 	/*
1943 	 * If the mount request that resulted in the creation of the
1944 	 * session requires encryption, force IPC to be encrypted too.
1945 	 */
1946 	if (ctx->seal) {
1947 		if (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
1948 			seal = true;
1949 		else {
1950 			cifs_server_dbg(VFS,
1951 				 "IPC: server doesn't support encryption\n");
1952 			return -EOPNOTSUPP;
1953 		}
1954 	}
1955 
1956 	/* no need to setup directory caching on IPC share, so pass in false */
1957 	tcon = tcon_info_alloc(false, netfs_trace_tcon_ref_new_ipc);
1958 	if (tcon == NULL)
1959 		return -ENOMEM;
1960 
1961 	spin_lock(&server->srv_lock);
1962 	scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", server->hostname);
1963 	spin_unlock(&server->srv_lock);
1964 
1965 	xid = get_xid();
1966 	tcon->ses = ses;
1967 	tcon->ipc = true;
1968 	tcon->seal = seal;
1969 	rc = server->ops->tree_connect(xid, ses, unc, tcon, ctx->local_nls);
1970 	free_xid(xid);
1971 
1972 	if (rc) {
1973 		cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
1974 		tconInfoFree(tcon, netfs_trace_tcon_ref_free_ipc_fail);
1975 		goto out;
1976 	}
1977 
1978 	cifs_dbg(FYI, "IPC tcon rc=%d ipc tid=0x%x\n", rc, tcon->tid);
1979 
1980 	spin_lock(&tcon->tc_lock);
1981 	tcon->status = TID_GOOD;
1982 	spin_unlock(&tcon->tc_lock);
1983 	ses->tcon_ipc = tcon;
1984 out:
1985 	return rc;
1986 }
1987 
1988 static struct cifs_ses *
1989 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1990 {
1991 	struct cifs_ses *ses, *ret = NULL;
1992 
1993 	spin_lock(&cifs_tcp_ses_lock);
1994 	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1995 		spin_lock(&ses->ses_lock);
1996 		if (ses->ses_status == SES_EXITING) {
1997 			spin_unlock(&ses->ses_lock);
1998 			continue;
1999 		}
2000 		spin_lock(&ses->chan_lock);
2001 		if (match_session(ses, ctx)) {
2002 			spin_unlock(&ses->chan_lock);
2003 			spin_unlock(&ses->ses_lock);
2004 			ret = ses;
2005 			break;
2006 		}
2007 		spin_unlock(&ses->chan_lock);
2008 		spin_unlock(&ses->ses_lock);
2009 	}
2010 	if (ret)
2011 		cifs_smb_ses_inc_refcount(ret);
2012 	spin_unlock(&cifs_tcp_ses_lock);
2013 	return ret;
2014 }
2015 
2016 void __cifs_put_smb_ses(struct cifs_ses *ses)
2017 {
2018 	struct TCP_Server_Info *server = ses->server;
2019 	struct cifs_tcon *tcon;
2020 	unsigned int xid;
2021 	size_t i;
2022 	bool do_logoff;
2023 	int rc;
2024 
2025 	spin_lock(&cifs_tcp_ses_lock);
2026 	spin_lock(&ses->ses_lock);
2027 	cifs_dbg(FYI, "%s: id=0x%llx ses_count=%d ses_status=%u ipc=%s\n",
2028 		 __func__, ses->Suid, ses->ses_count, ses->ses_status,
2029 		 ses->tcon_ipc ? ses->tcon_ipc->tree_name : "none");
2030 	if (ses->ses_status == SES_EXITING || --ses->ses_count > 0) {
2031 		spin_unlock(&ses->ses_lock);
2032 		spin_unlock(&cifs_tcp_ses_lock);
2033 		return;
2034 	}
2035 	/* ses_count can never go negative */
2036 	WARN_ON(ses->ses_count < 0);
2037 
2038 	spin_lock(&ses->chan_lock);
2039 	cifs_chan_clear_need_reconnect(ses, server);
2040 	spin_unlock(&ses->chan_lock);
2041 
2042 	do_logoff = ses->ses_status == SES_GOOD && server->ops->logoff;
2043 	ses->ses_status = SES_EXITING;
2044 	tcon = ses->tcon_ipc;
2045 	ses->tcon_ipc = NULL;
2046 	spin_unlock(&ses->ses_lock);
2047 	spin_unlock(&cifs_tcp_ses_lock);
2048 
2049 	/*
2050 	 * On session close, the IPC is closed and the server must release all
2051 	 * tcons of the session.  No need to send a tree disconnect here.
2052 	 *
2053 	 * Besides, it will make the server to not close durable and resilient
2054 	 * files on session close, as specified in MS-SMB2 3.3.5.6 Receiving an
2055 	 * SMB2 LOGOFF Request.
2056 	 */
2057 	tconInfoFree(tcon, netfs_trace_tcon_ref_free_ipc);
2058 	if (do_logoff) {
2059 		xid = get_xid();
2060 		rc = server->ops->logoff(xid, ses);
2061 		if (rc)
2062 			cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
2063 				__func__, rc);
2064 		_free_xid(xid);
2065 	}
2066 
2067 	spin_lock(&cifs_tcp_ses_lock);
2068 	list_del_init(&ses->smb_ses_list);
2069 	spin_unlock(&cifs_tcp_ses_lock);
2070 
2071 	/* close any extra channels */
2072 	for (i = 1; i < ses->chan_count; i++) {
2073 		if (ses->chans[i].iface) {
2074 			kref_put(&ses->chans[i].iface->refcount, release_iface);
2075 			ses->chans[i].iface = NULL;
2076 		}
2077 		cifs_put_tcp_session(ses->chans[i].server, 0);
2078 		ses->chans[i].server = NULL;
2079 	}
2080 
2081 	/* we now account for primary channel in iface->refcount */
2082 	if (ses->chans[0].iface) {
2083 		kref_put(&ses->chans[0].iface->refcount, release_iface);
2084 		ses->chans[0].server = NULL;
2085 	}
2086 
2087 	sesInfoFree(ses);
2088 	cifs_put_tcp_session(server, 0);
2089 }
2090 
2091 #ifdef CONFIG_KEYS
2092 
2093 /* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
2094 #define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
2095 
2096 /* Populate username and pw fields from keyring if possible */
2097 static int
2098 cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
2099 {
2100 	int rc = 0;
2101 	int is_domain = 0;
2102 	const char *delim, *payload;
2103 	char *desc;
2104 	ssize_t len;
2105 	struct key *key;
2106 	struct TCP_Server_Info *server = ses->server;
2107 	struct sockaddr_in *sa;
2108 	struct sockaddr_in6 *sa6;
2109 	const struct user_key_payload *upayload;
2110 
2111 	desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
2112 	if (!desc)
2113 		return -ENOMEM;
2114 
2115 	/* try to find an address key first */
2116 	switch (server->dstaddr.ss_family) {
2117 	case AF_INET:
2118 		sa = (struct sockaddr_in *)&server->dstaddr;
2119 		sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
2120 		break;
2121 	case AF_INET6:
2122 		sa6 = (struct sockaddr_in6 *)&server->dstaddr;
2123 		sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
2124 		break;
2125 	default:
2126 		cifs_dbg(FYI, "Bad ss_family (%hu)\n",
2127 			 server->dstaddr.ss_family);
2128 		rc = -EINVAL;
2129 		goto out_err;
2130 	}
2131 
2132 	cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
2133 	key = request_key(&key_type_logon, desc, "");
2134 	if (IS_ERR(key)) {
2135 		if (!ses->domainName) {
2136 			cifs_dbg(FYI, "domainName is NULL\n");
2137 			rc = PTR_ERR(key);
2138 			goto out_err;
2139 		}
2140 
2141 		/* didn't work, try to find a domain key */
2142 		sprintf(desc, "cifs:d:%s", ses->domainName);
2143 		cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
2144 		key = request_key(&key_type_logon, desc, "");
2145 		if (IS_ERR(key)) {
2146 			rc = PTR_ERR(key);
2147 			goto out_err;
2148 		}
2149 		is_domain = 1;
2150 	}
2151 
2152 	down_read(&key->sem);
2153 	upayload = user_key_payload_locked(key);
2154 	if (IS_ERR_OR_NULL(upayload)) {
2155 		rc = upayload ? PTR_ERR(upayload) : -EINVAL;
2156 		goto out_key_put;
2157 	}
2158 
2159 	/* find first : in payload */
2160 	payload = upayload->data;
2161 	delim = strnchr(payload, upayload->datalen, ':');
2162 	cifs_dbg(FYI, "payload=%s\n", payload);
2163 	if (!delim) {
2164 		cifs_dbg(FYI, "Unable to find ':' in payload (datalen=%d)\n",
2165 			 upayload->datalen);
2166 		rc = -EINVAL;
2167 		goto out_key_put;
2168 	}
2169 
2170 	len = delim - payload;
2171 	if (len > CIFS_MAX_USERNAME_LEN || len <= 0) {
2172 		cifs_dbg(FYI, "Bad value from username search (len=%zd)\n",
2173 			 len);
2174 		rc = -EINVAL;
2175 		goto out_key_put;
2176 	}
2177 
2178 	ctx->username = kstrndup(payload, len, GFP_KERNEL);
2179 	if (!ctx->username) {
2180 		cifs_dbg(FYI, "Unable to allocate %zd bytes for username\n",
2181 			 len);
2182 		rc = -ENOMEM;
2183 		goto out_key_put;
2184 	}
2185 	cifs_dbg(FYI, "%s: username=%s\n", __func__, ctx->username);
2186 
2187 	len = key->datalen - (len + 1);
2188 	if (len > CIFS_MAX_PASSWORD_LEN || len <= 0) {
2189 		cifs_dbg(FYI, "Bad len for password search (len=%zd)\n", len);
2190 		rc = -EINVAL;
2191 		kfree(ctx->username);
2192 		ctx->username = NULL;
2193 		goto out_key_put;
2194 	}
2195 
2196 	++delim;
2197 	/* BB consider adding support for password2 (Key Rotation) for multiuser in future */
2198 	ctx->password = kstrndup(delim, len, GFP_KERNEL);
2199 	if (!ctx->password) {
2200 		cifs_dbg(FYI, "Unable to allocate %zd bytes for password\n",
2201 			 len);
2202 		rc = -ENOMEM;
2203 		kfree(ctx->username);
2204 		ctx->username = NULL;
2205 		goto out_key_put;
2206 	}
2207 
2208 	/*
2209 	 * If we have a domain key then we must set the domainName in the
2210 	 * for the request.
2211 	 */
2212 	if (is_domain && ses->domainName) {
2213 		ctx->domainname = kstrdup(ses->domainName, GFP_KERNEL);
2214 		if (!ctx->domainname) {
2215 			cifs_dbg(FYI, "Unable to allocate %zd bytes for domain\n",
2216 				 len);
2217 			rc = -ENOMEM;
2218 			kfree(ctx->username);
2219 			ctx->username = NULL;
2220 			kfree_sensitive(ctx->password);
2221 			/* no need to free ctx->password2 since not allocated in this path */
2222 			ctx->password = NULL;
2223 			goto out_key_put;
2224 		}
2225 	}
2226 
2227 	strscpy(ctx->workstation_name, ses->workstation_name, sizeof(ctx->workstation_name));
2228 
2229 out_key_put:
2230 	up_read(&key->sem);
2231 	key_put(key);
2232 out_err:
2233 	kfree(desc);
2234 	cifs_dbg(FYI, "%s: returning %d\n", __func__, rc);
2235 	return rc;
2236 }
2237 #else /* ! CONFIG_KEYS */
2238 static inline int
2239 cifs_set_cifscreds(struct smb3_fs_context *ctx __attribute__((unused)),
2240 		   struct cifs_ses *ses __attribute__((unused)))
2241 {
2242 	return -ENOSYS;
2243 }
2244 #endif /* CONFIG_KEYS */
2245 
2246 /**
2247  * cifs_get_smb_ses - get a session matching @ctx data from @server
2248  * @server: server to setup the session to
2249  * @ctx: superblock configuration context to use to setup the session
2250  *
2251  * This function assumes it is being called from cifs_mount() where we
2252  * already got a server reference (server refcount +1). See
2253  * cifs_get_tcon() for refcount explanations.
2254  */
2255 struct cifs_ses *
2256 cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
2257 {
2258 	int rc = 0;
2259 	unsigned int xid;
2260 	struct cifs_ses *ses;
2261 	struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
2262 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
2263 
2264 	xid = get_xid();
2265 
2266 	ses = cifs_find_smb_ses(server, ctx);
2267 	if (ses) {
2268 		cifs_dbg(FYI, "Existing smb sess found (status=%d)\n",
2269 			 ses->ses_status);
2270 
2271 		spin_lock(&ses->chan_lock);
2272 		if (cifs_chan_needs_reconnect(ses, server)) {
2273 			spin_unlock(&ses->chan_lock);
2274 			cifs_dbg(FYI, "Session needs reconnect\n");
2275 
2276 			mutex_lock(&ses->session_mutex);
2277 			rc = cifs_negotiate_protocol(xid, ses, server);
2278 			if (rc) {
2279 				mutex_unlock(&ses->session_mutex);
2280 				/* problem -- put our ses reference */
2281 				cifs_put_smb_ses(ses);
2282 				free_xid(xid);
2283 				return ERR_PTR(rc);
2284 			}
2285 
2286 			rc = cifs_setup_session(xid, ses, server,
2287 						ctx->local_nls);
2288 			if (rc) {
2289 				mutex_unlock(&ses->session_mutex);
2290 				/* problem -- put our reference */
2291 				cifs_put_smb_ses(ses);
2292 				free_xid(xid);
2293 				return ERR_PTR(rc);
2294 			}
2295 			mutex_unlock(&ses->session_mutex);
2296 
2297 			spin_lock(&ses->chan_lock);
2298 		}
2299 		spin_unlock(&ses->chan_lock);
2300 
2301 		/* existing SMB ses has a server reference already */
2302 		cifs_put_tcp_session(server, 0);
2303 		free_xid(xid);
2304 		return ses;
2305 	}
2306 
2307 	rc = -ENOMEM;
2308 
2309 	cifs_dbg(FYI, "Existing smb sess not found\n");
2310 	ses = sesInfoAlloc();
2311 	if (ses == NULL)
2312 		goto get_ses_fail;
2313 
2314 	/* new SMB session uses our server ref */
2315 	ses->server = server;
2316 	if (server->dstaddr.ss_family == AF_INET6)
2317 		sprintf(ses->ip_addr, "%pI6", &addr6->sin6_addr);
2318 	else
2319 		sprintf(ses->ip_addr, "%pI4", &addr->sin_addr);
2320 
2321 	if (ctx->username) {
2322 		ses->user_name = kstrdup(ctx->username, GFP_KERNEL);
2323 		if (!ses->user_name)
2324 			goto get_ses_fail;
2325 	}
2326 
2327 	/* ctx->password freed at unmount */
2328 	if (ctx->password) {
2329 		ses->password = kstrdup(ctx->password, GFP_KERNEL);
2330 		if (!ses->password)
2331 			goto get_ses_fail;
2332 	}
2333 	/* ctx->password freed at unmount */
2334 	if (ctx->password2) {
2335 		ses->password2 = kstrdup(ctx->password2, GFP_KERNEL);
2336 		if (!ses->password2)
2337 			goto get_ses_fail;
2338 	}
2339 	if (ctx->domainname) {
2340 		ses->domainName = kstrdup(ctx->domainname, GFP_KERNEL);
2341 		if (!ses->domainName)
2342 			goto get_ses_fail;
2343 	}
2344 
2345 	strscpy(ses->workstation_name, ctx->workstation_name, sizeof(ses->workstation_name));
2346 
2347 	if (ctx->domainauto)
2348 		ses->domainAuto = ctx->domainauto;
2349 	ses->cred_uid = ctx->cred_uid;
2350 	ses->linux_uid = ctx->linux_uid;
2351 
2352 	ses->sectype = ctx->sectype;
2353 	ses->sign = ctx->sign;
2354 	ses->local_nls = load_nls(ctx->local_nls->charset);
2355 
2356 	/* add server as first channel */
2357 	spin_lock(&ses->chan_lock);
2358 	ses->chans[0].server = server;
2359 	ses->chan_count = 1;
2360 	ses->chan_max = ctx->multichannel ? ctx->max_channels:1;
2361 	ses->chans_need_reconnect = 1;
2362 	spin_unlock(&ses->chan_lock);
2363 
2364 	mutex_lock(&ses->session_mutex);
2365 	rc = cifs_negotiate_protocol(xid, ses, server);
2366 	if (!rc)
2367 		rc = cifs_setup_session(xid, ses, server, ctx->local_nls);
2368 	mutex_unlock(&ses->session_mutex);
2369 
2370 	/* each channel uses a different signing key */
2371 	spin_lock(&ses->chan_lock);
2372 	memcpy(ses->chans[0].signkey, ses->smb3signingkey,
2373 	       sizeof(ses->smb3signingkey));
2374 	spin_unlock(&ses->chan_lock);
2375 
2376 	if (rc)
2377 		goto get_ses_fail;
2378 
2379 	/*
2380 	 * success, put it on the list and add it as first channel
2381 	 * note: the session becomes active soon after this. So you'll
2382 	 * need to lock before changing something in the session.
2383 	 */
2384 	spin_lock(&cifs_tcp_ses_lock);
2385 	if (ctx->dfs_root_ses)
2386 		cifs_smb_ses_inc_refcount(ctx->dfs_root_ses);
2387 	ses->dfs_root_ses = ctx->dfs_root_ses;
2388 	list_add(&ses->smb_ses_list, &server->smb_ses_list);
2389 	spin_unlock(&cifs_tcp_ses_lock);
2390 
2391 	cifs_setup_ipc(ses, ctx);
2392 
2393 	free_xid(xid);
2394 
2395 	return ses;
2396 
2397 get_ses_fail:
2398 	sesInfoFree(ses);
2399 	free_xid(xid);
2400 	return ERR_PTR(rc);
2401 }
2402 
2403 /* this function must be called with tc_lock held */
2404 static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
2405 {
2406 	struct TCP_Server_Info *server = tcon->ses->server;
2407 
2408 	if (tcon->status == TID_EXITING)
2409 		return 0;
2410 
2411 	if (tcon->origin_fullpath) {
2412 		if (!ctx->source ||
2413 		    !dfs_src_pathname_equal(ctx->source,
2414 					    tcon->origin_fullpath))
2415 			return 0;
2416 	} else if (!server->leaf_fullpath &&
2417 		   strncmp(tcon->tree_name, ctx->UNC, MAX_TREE_SIZE)) {
2418 		return 0;
2419 	}
2420 	if (tcon->seal != ctx->seal)
2421 		return 0;
2422 	if (tcon->snapshot_time != ctx->snapshot_time)
2423 		return 0;
2424 	if (tcon->handle_timeout != ctx->handle_timeout)
2425 		return 0;
2426 	if (tcon->no_lease != ctx->no_lease)
2427 		return 0;
2428 	if (tcon->nodelete != ctx->nodelete)
2429 		return 0;
2430 	return 1;
2431 }
2432 
2433 static struct cifs_tcon *
2434 cifs_find_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2435 {
2436 	struct cifs_tcon *tcon;
2437 
2438 	spin_lock(&cifs_tcp_ses_lock);
2439 	list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
2440 		spin_lock(&tcon->tc_lock);
2441 		if (!match_tcon(tcon, ctx)) {
2442 			spin_unlock(&tcon->tc_lock);
2443 			continue;
2444 		}
2445 		++tcon->tc_count;
2446 		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
2447 				    netfs_trace_tcon_ref_get_find);
2448 		spin_unlock(&tcon->tc_lock);
2449 		spin_unlock(&cifs_tcp_ses_lock);
2450 		return tcon;
2451 	}
2452 	spin_unlock(&cifs_tcp_ses_lock);
2453 	return NULL;
2454 }
2455 
2456 void
2457 cifs_put_tcon(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
2458 {
2459 	unsigned int xid;
2460 	struct cifs_ses *ses;
2461 
2462 	/*
2463 	 * IPC tcon share the lifetime of their session and are
2464 	 * destroyed in the session put function
2465 	 */
2466 	if (tcon == NULL || tcon->ipc)
2467 		return;
2468 
2469 	ses = tcon->ses;
2470 	cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
2471 	spin_lock(&cifs_tcp_ses_lock);
2472 	spin_lock(&tcon->tc_lock);
2473 	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count - 1, trace);
2474 	if (--tcon->tc_count > 0) {
2475 		spin_unlock(&tcon->tc_lock);
2476 		spin_unlock(&cifs_tcp_ses_lock);
2477 		return;
2478 	}
2479 
2480 	/* tc_count can never go negative */
2481 	WARN_ON(tcon->tc_count < 0);
2482 
2483 	list_del_init(&tcon->tcon_list);
2484 	tcon->status = TID_EXITING;
2485 	spin_unlock(&tcon->tc_lock);
2486 	spin_unlock(&cifs_tcp_ses_lock);
2487 
2488 	/* cancel polling of interfaces */
2489 	cancel_delayed_work_sync(&tcon->query_interfaces);
2490 #ifdef CONFIG_CIFS_DFS_UPCALL
2491 	cancel_delayed_work_sync(&tcon->dfs_cache_work);
2492 #endif
2493 
2494 	if (tcon->use_witness) {
2495 		int rc;
2496 
2497 		rc = cifs_swn_unregister(tcon);
2498 		if (rc < 0) {
2499 			cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
2500 					__func__, rc);
2501 		}
2502 	}
2503 
2504 	xid = get_xid();
2505 	if (ses->server->ops->tree_disconnect)
2506 		ses->server->ops->tree_disconnect(xid, tcon);
2507 	_free_xid(xid);
2508 
2509 	cifs_fscache_release_super_cookie(tcon);
2510 	tconInfoFree(tcon, netfs_trace_tcon_ref_free);
2511 	cifs_put_smb_ses(ses);
2512 }
2513 
2514 /**
2515  * cifs_get_tcon - get a tcon matching @ctx data from @ses
2516  * @ses: smb session to issue the request on
2517  * @ctx: the superblock configuration context to use for building the
2518  *
2519  * - tcon refcount is the number of mount points using the tcon.
2520  * - ses refcount is the number of tcon using the session.
2521  *
2522  * 1. This function assumes it is being called from cifs_mount() where
2523  *    we already got a session reference (ses refcount +1).
2524  *
2525  * 2. Since we're in the context of adding a mount point, the end
2526  *    result should be either:
2527  *
2528  * a) a new tcon already allocated with refcount=1 (1 mount point) and
2529  *    its session refcount incremented (1 new tcon). This +1 was
2530  *    already done in (1).
2531  *
2532  * b) an existing tcon with refcount+1 (add a mount point to it) and
2533  *    identical ses refcount (no new tcon). Because of (1) we need to
2534  *    decrement the ses refcount.
2535  */
2536 static struct cifs_tcon *
2537 cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2538 {
2539 	struct cifs_tcon *tcon;
2540 	bool nohandlecache;
2541 	int rc, xid;
2542 
2543 	tcon = cifs_find_tcon(ses, ctx);
2544 	if (tcon) {
2545 		/*
2546 		 * tcon has refcount already incremented but we need to
2547 		 * decrement extra ses reference gotten by caller (case b)
2548 		 */
2549 		cifs_dbg(FYI, "Found match on UNC path\n");
2550 		cifs_put_smb_ses(ses);
2551 		return tcon;
2552 	}
2553 
2554 	if (!ses->server->ops->tree_connect) {
2555 		rc = -ENOSYS;
2556 		goto out_fail;
2557 	}
2558 
2559 	if (ses->server->dialect >= SMB20_PROT_ID &&
2560 	    (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING))
2561 		nohandlecache = ctx->nohandlecache;
2562 	else
2563 		nohandlecache = true;
2564 	tcon = tcon_info_alloc(!nohandlecache, netfs_trace_tcon_ref_new);
2565 	if (tcon == NULL) {
2566 		rc = -ENOMEM;
2567 		goto out_fail;
2568 	}
2569 	tcon->nohandlecache = nohandlecache;
2570 
2571 	if (ctx->snapshot_time) {
2572 		if (ses->server->vals->protocol_id == 0) {
2573 			cifs_dbg(VFS,
2574 			     "Use SMB2 or later for snapshot mount option\n");
2575 			rc = -EOPNOTSUPP;
2576 			goto out_fail;
2577 		} else
2578 			tcon->snapshot_time = ctx->snapshot_time;
2579 	}
2580 
2581 	if (ctx->handle_timeout) {
2582 		if (ses->server->vals->protocol_id == 0) {
2583 			cifs_dbg(VFS,
2584 			     "Use SMB2.1 or later for handle timeout option\n");
2585 			rc = -EOPNOTSUPP;
2586 			goto out_fail;
2587 		} else
2588 			tcon->handle_timeout = ctx->handle_timeout;
2589 	}
2590 
2591 	tcon->ses = ses;
2592 	if (ctx->password) {
2593 		tcon->password = kstrdup(ctx->password, GFP_KERNEL);
2594 		if (!tcon->password) {
2595 			rc = -ENOMEM;
2596 			goto out_fail;
2597 		}
2598 	}
2599 
2600 	if (ctx->seal) {
2601 		if (ses->server->vals->protocol_id == 0) {
2602 			cifs_dbg(VFS,
2603 				 "SMB3 or later required for encryption\n");
2604 			rc = -EOPNOTSUPP;
2605 			goto out_fail;
2606 		} else if (tcon->ses->server->capabilities &
2607 					SMB2_GLOBAL_CAP_ENCRYPTION)
2608 			tcon->seal = true;
2609 		else {
2610 			cifs_dbg(VFS, "Encryption is not supported on share\n");
2611 			rc = -EOPNOTSUPP;
2612 			goto out_fail;
2613 		}
2614 	}
2615 
2616 	if (ctx->linux_ext) {
2617 		if (ses->server->posix_ext_supported) {
2618 			tcon->posix_extensions = true;
2619 			pr_warn_once("SMB3.11 POSIX Extensions are experimental\n");
2620 		} else if ((ses->server->vals->protocol_id == SMB311_PROT_ID) ||
2621 		    (strcmp(ses->server->vals->version_string,
2622 		     SMB3ANY_VERSION_STRING) == 0) ||
2623 		    (strcmp(ses->server->vals->version_string,
2624 		     SMBDEFAULT_VERSION_STRING) == 0)) {
2625 			cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions\n");
2626 			rc = -EOPNOTSUPP;
2627 			goto out_fail;
2628 		} else if (ses->server->vals->protocol_id == SMB10_PROT_ID)
2629 			if (cap_unix(ses))
2630 				cifs_dbg(FYI, "Unix Extensions requested on SMB1 mount\n");
2631 			else {
2632 				cifs_dbg(VFS, "SMB1 Unix Extensions not supported by server\n");
2633 				rc = -EOPNOTSUPP;
2634 				goto out_fail;
2635 		} else {
2636 			cifs_dbg(VFS,
2637 				"Check vers= mount option. SMB3.11 disabled but required for POSIX extensions\n");
2638 			rc = -EOPNOTSUPP;
2639 			goto out_fail;
2640 		}
2641 	}
2642 
2643 	xid = get_xid();
2644 	rc = ses->server->ops->tree_connect(xid, ses, ctx->UNC, tcon,
2645 					    ctx->local_nls);
2646 	free_xid(xid);
2647 	cifs_dbg(FYI, "Tcon rc = %d\n", rc);
2648 	if (rc)
2649 		goto out_fail;
2650 
2651 	tcon->use_persistent = false;
2652 	/* check if SMB2 or later, CIFS does not support persistent handles */
2653 	if (ctx->persistent) {
2654 		if (ses->server->vals->protocol_id == 0) {
2655 			cifs_dbg(VFS,
2656 			     "SMB3 or later required for persistent handles\n");
2657 			rc = -EOPNOTSUPP;
2658 			goto out_fail;
2659 		} else if (ses->server->capabilities &
2660 			   SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2661 			tcon->use_persistent = true;
2662 		else /* persistent handles requested but not supported */ {
2663 			cifs_dbg(VFS,
2664 				"Persistent handles not supported on share\n");
2665 			rc = -EOPNOTSUPP;
2666 			goto out_fail;
2667 		}
2668 	} else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
2669 	     && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2670 	     && (ctx->nopersistent == false)) {
2671 		cifs_dbg(FYI, "enabling persistent handles\n");
2672 		tcon->use_persistent = true;
2673 	} else if (ctx->resilient) {
2674 		if (ses->server->vals->protocol_id == 0) {
2675 			cifs_dbg(VFS,
2676 			     "SMB2.1 or later required for resilient handles\n");
2677 			rc = -EOPNOTSUPP;
2678 			goto out_fail;
2679 		}
2680 		tcon->use_resilient = true;
2681 	}
2682 
2683 	tcon->use_witness = false;
2684 	if (IS_ENABLED(CONFIG_CIFS_SWN_UPCALL) && ctx->witness) {
2685 		if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
2686 			if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
2687 				/*
2688 				 * Set witness in use flag in first place
2689 				 * to retry registration in the echo task
2690 				 */
2691 				tcon->use_witness = true;
2692 				/* And try to register immediately */
2693 				rc = cifs_swn_register(tcon);
2694 				if (rc < 0) {
2695 					cifs_dbg(VFS, "Failed to register for witness notifications: %d\n", rc);
2696 					goto out_fail;
2697 				}
2698 			} else {
2699 				/* TODO: try to extend for non-cluster uses (eg multichannel) */
2700 				cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
2701 				rc = -EOPNOTSUPP;
2702 				goto out_fail;
2703 			}
2704 		} else {
2705 			cifs_dbg(VFS, "SMB3 or later required for witness option\n");
2706 			rc = -EOPNOTSUPP;
2707 			goto out_fail;
2708 		}
2709 	}
2710 
2711 	/* If the user really knows what they are doing they can override */
2712 	if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
2713 		if (ctx->cache_ro)
2714 			cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING flag set on share\n");
2715 		else if (ctx->cache_rw)
2716 			cifs_dbg(VFS, "cache=singleclient requested on mount but NO_CACHING flag set on share\n");
2717 	}
2718 
2719 	if (ctx->no_lease) {
2720 		if (ses->server->vals->protocol_id == 0) {
2721 			cifs_dbg(VFS,
2722 				"SMB2 or later required for nolease option\n");
2723 			rc = -EOPNOTSUPP;
2724 			goto out_fail;
2725 		} else
2726 			tcon->no_lease = ctx->no_lease;
2727 	}
2728 
2729 	/*
2730 	 * We can have only one retry value for a connection to a share so for
2731 	 * resources mounted more than once to the same server share the last
2732 	 * value passed in for the retry flag is used.
2733 	 */
2734 	tcon->retry = ctx->retry;
2735 	tcon->nocase = ctx->nocase;
2736 	tcon->broken_sparse_sup = ctx->no_sparse;
2737 	tcon->max_cached_dirs = ctx->max_cached_dirs;
2738 	tcon->nodelete = ctx->nodelete;
2739 	tcon->local_lease = ctx->local_lease;
2740 	INIT_LIST_HEAD(&tcon->pending_opens);
2741 	tcon->status = TID_GOOD;
2742 
2743 	INIT_DELAYED_WORK(&tcon->query_interfaces,
2744 			  smb2_query_server_interfaces);
2745 	if (ses->server->dialect >= SMB30_PROT_ID &&
2746 	    (ses->server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
2747 		/* schedule query interfaces poll */
2748 		queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
2749 				   (SMB_INTERFACE_POLL_INTERVAL * HZ));
2750 	}
2751 #ifdef CONFIG_CIFS_DFS_UPCALL
2752 	INIT_DELAYED_WORK(&tcon->dfs_cache_work, dfs_cache_refresh);
2753 #endif
2754 	spin_lock(&cifs_tcp_ses_lock);
2755 	list_add(&tcon->tcon_list, &ses->tcon_list);
2756 	spin_unlock(&cifs_tcp_ses_lock);
2757 
2758 	return tcon;
2759 
2760 out_fail:
2761 	tconInfoFree(tcon, netfs_trace_tcon_ref_free_fail);
2762 	return ERR_PTR(rc);
2763 }
2764 
2765 void
2766 cifs_put_tlink(struct tcon_link *tlink)
2767 {
2768 	if (!tlink || IS_ERR(tlink))
2769 		return;
2770 
2771 	if (!atomic_dec_and_test(&tlink->tl_count) ||
2772 	    test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
2773 		tlink->tl_time = jiffies;
2774 		return;
2775 	}
2776 
2777 	if (!IS_ERR(tlink_tcon(tlink)))
2778 		cifs_put_tcon(tlink_tcon(tlink), netfs_trace_tcon_ref_put_tlink);
2779 	kfree(tlink);
2780 }
2781 
2782 static int
2783 compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2784 {
2785 	struct cifs_sb_info *old = CIFS_SB(sb);
2786 	struct cifs_sb_info *new = mnt_data->cifs_sb;
2787 	unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
2788 	unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;
2789 
2790 	if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
2791 		return 0;
2792 
2793 	if (old->mnt_cifs_serverino_autodisabled)
2794 		newflags &= ~CIFS_MOUNT_SERVER_INUM;
2795 
2796 	if (oldflags != newflags)
2797 		return 0;
2798 
2799 	/*
2800 	 * We want to share sb only if we don't specify an r/wsize or
2801 	 * specified r/wsize is greater than or equal to existing one.
2802 	 */
2803 	if (new->ctx->wsize && new->ctx->wsize < old->ctx->wsize)
2804 		return 0;
2805 
2806 	if (new->ctx->rsize && new->ctx->rsize < old->ctx->rsize)
2807 		return 0;
2808 
2809 	if (!uid_eq(old->ctx->linux_uid, new->ctx->linux_uid) ||
2810 	    !gid_eq(old->ctx->linux_gid, new->ctx->linux_gid))
2811 		return 0;
2812 
2813 	if (old->ctx->file_mode != new->ctx->file_mode ||
2814 	    old->ctx->dir_mode != new->ctx->dir_mode)
2815 		return 0;
2816 
2817 	if (strcmp(old->local_nls->charset, new->local_nls->charset))
2818 		return 0;
2819 
2820 	if (old->ctx->acregmax != new->ctx->acregmax)
2821 		return 0;
2822 	if (old->ctx->acdirmax != new->ctx->acdirmax)
2823 		return 0;
2824 	if (old->ctx->closetimeo != new->ctx->closetimeo)
2825 		return 0;
2826 	if (old->ctx->reparse_type != new->ctx->reparse_type)
2827 		return 0;
2828 
2829 	return 1;
2830 }
2831 
2832 static int match_prepath(struct super_block *sb,
2833 			 struct cifs_tcon *tcon,
2834 			 struct cifs_mnt_data *mnt_data)
2835 {
2836 	struct smb3_fs_context *ctx = mnt_data->ctx;
2837 	struct cifs_sb_info *old = CIFS_SB(sb);
2838 	struct cifs_sb_info *new = mnt_data->cifs_sb;
2839 	bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2840 		old->prepath;
2841 	bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2842 		new->prepath;
2843 
2844 	if (tcon->origin_fullpath &&
2845 	    dfs_src_pathname_equal(tcon->origin_fullpath, ctx->source))
2846 		return 1;
2847 
2848 	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
2849 		return 1;
2850 	else if (!old_set && !new_set)
2851 		return 1;
2852 
2853 	return 0;
2854 }
2855 
2856 int
2857 cifs_match_super(struct super_block *sb, void *data)
2858 {
2859 	struct cifs_mnt_data *mnt_data = data;
2860 	struct smb3_fs_context *ctx;
2861 	struct cifs_sb_info *cifs_sb;
2862 	struct TCP_Server_Info *tcp_srv;
2863 	struct cifs_ses *ses;
2864 	struct cifs_tcon *tcon;
2865 	struct tcon_link *tlink;
2866 	int rc = 0;
2867 
2868 	spin_lock(&cifs_tcp_ses_lock);
2869 	cifs_sb = CIFS_SB(sb);
2870 
2871 	/* We do not want to use a superblock that has been shutdown */
2872 	if (CIFS_MOUNT_SHUTDOWN & cifs_sb->mnt_cifs_flags) {
2873 		spin_unlock(&cifs_tcp_ses_lock);
2874 		return 0;
2875 	}
2876 
2877 	tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
2878 	if (IS_ERR_OR_NULL(tlink)) {
2879 		pr_warn_once("%s: skip super matching due to bad tlink(%p)\n",
2880 			     __func__, tlink);
2881 		spin_unlock(&cifs_tcp_ses_lock);
2882 		return 0;
2883 	}
2884 	tcon = tlink_tcon(tlink);
2885 	ses = tcon->ses;
2886 	tcp_srv = ses->server;
2887 
2888 	ctx = mnt_data->ctx;
2889 
2890 	spin_lock(&tcp_srv->srv_lock);
2891 	spin_lock(&ses->ses_lock);
2892 	spin_lock(&ses->chan_lock);
2893 	spin_lock(&tcon->tc_lock);
2894 	if (!match_server(tcp_srv, ctx, true) ||
2895 	    !match_session(ses, ctx) ||
2896 	    !match_tcon(tcon, ctx) ||
2897 	    !match_prepath(sb, tcon, mnt_data)) {
2898 		rc = 0;
2899 		goto out;
2900 	}
2901 
2902 	rc = compare_mount_options(sb, mnt_data);
2903 out:
2904 	spin_unlock(&tcon->tc_lock);
2905 	spin_unlock(&ses->chan_lock);
2906 	spin_unlock(&ses->ses_lock);
2907 	spin_unlock(&tcp_srv->srv_lock);
2908 
2909 	spin_unlock(&cifs_tcp_ses_lock);
2910 	cifs_put_tlink(tlink);
2911 	return rc;
2912 }
2913 
2914 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2915 static struct lock_class_key cifs_key[2];
2916 static struct lock_class_key cifs_slock_key[2];
2917 
2918 static inline void
2919 cifs_reclassify_socket4(struct socket *sock)
2920 {
2921 	struct sock *sk = sock->sk;
2922 
2923 	BUG_ON(!sock_allow_reclassification(sk));
2924 	sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS",
2925 		&cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]);
2926 }
2927 
2928 static inline void
2929 cifs_reclassify_socket6(struct socket *sock)
2930 {
2931 	struct sock *sk = sock->sk;
2932 
2933 	BUG_ON(!sock_allow_reclassification(sk));
2934 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS",
2935 		&cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]);
2936 }
2937 #else
2938 static inline void
2939 cifs_reclassify_socket4(struct socket *sock)
2940 {
2941 }
2942 
2943 static inline void
2944 cifs_reclassify_socket6(struct socket *sock)
2945 {
2946 }
2947 #endif
2948 
2949 /* See RFC1001 section 14 on representation of Netbios names */
2950 static void rfc1002mangle(char *target, char *source, unsigned int length)
2951 {
2952 	unsigned int i, j;
2953 
2954 	for (i = 0, j = 0; i < (length); i++) {
2955 		/* mask a nibble at a time and encode */
2956 		target[j] = 'A' + (0x0F & (source[i] >> 4));
2957 		target[j+1] = 'A' + (0x0F & source[i]);
2958 		j += 2;
2959 	}
2960 
2961 }
2962 
2963 static int
2964 bind_socket(struct TCP_Server_Info *server)
2965 {
2966 	int rc = 0;
2967 
2968 	if (server->srcaddr.ss_family != AF_UNSPEC) {
2969 		/* Bind to the specified local IP address */
2970 		struct socket *socket = server->ssocket;
2971 
2972 		rc = kernel_bind(socket,
2973 				 (struct sockaddr *) &server->srcaddr,
2974 				 sizeof(server->srcaddr));
2975 		if (rc < 0) {
2976 			struct sockaddr_in *saddr4;
2977 			struct sockaddr_in6 *saddr6;
2978 
2979 			saddr4 = (struct sockaddr_in *)&server->srcaddr;
2980 			saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
2981 			if (saddr6->sin6_family == AF_INET6)
2982 				cifs_server_dbg(VFS, "Failed to bind to: %pI6c, error: %d\n",
2983 					 &saddr6->sin6_addr, rc);
2984 			else
2985 				cifs_server_dbg(VFS, "Failed to bind to: %pI4, error: %d\n",
2986 					 &saddr4->sin_addr.s_addr, rc);
2987 		}
2988 	}
2989 	return rc;
2990 }
2991 
2992 static int
2993 ip_rfc1001_connect(struct TCP_Server_Info *server)
2994 {
2995 	int rc = 0;
2996 	/*
2997 	 * some servers require RFC1001 sessinit before sending
2998 	 * negprot - BB check reconnection in case where second
2999 	 * sessinit is sent but no second negprot
3000 	 */
3001 	struct rfc1002_session_packet req = {};
3002 	struct smb_hdr *smb_buf = (struct smb_hdr *)&req;
3003 	unsigned int len;
3004 
3005 	req.trailer.session_req.called_len = sizeof(req.trailer.session_req.called_name);
3006 
3007 	if (server->server_RFC1001_name[0] != 0)
3008 		rfc1002mangle(req.trailer.session_req.called_name,
3009 			      server->server_RFC1001_name,
3010 			      RFC1001_NAME_LEN_WITH_NULL);
3011 	else
3012 		rfc1002mangle(req.trailer.session_req.called_name,
3013 			      DEFAULT_CIFS_CALLED_NAME,
3014 			      RFC1001_NAME_LEN_WITH_NULL);
3015 
3016 	req.trailer.session_req.calling_len = sizeof(req.trailer.session_req.calling_name);
3017 
3018 	/* calling name ends in null (byte 16) from old smb convention */
3019 	if (server->workstation_RFC1001_name[0] != 0)
3020 		rfc1002mangle(req.trailer.session_req.calling_name,
3021 			      server->workstation_RFC1001_name,
3022 			      RFC1001_NAME_LEN_WITH_NULL);
3023 	else
3024 		rfc1002mangle(req.trailer.session_req.calling_name,
3025 			      "LINUX_CIFS_CLNT",
3026 			      RFC1001_NAME_LEN_WITH_NULL);
3027 
3028 	/*
3029 	 * As per rfc1002, @len must be the number of bytes that follows the
3030 	 * length field of a rfc1002 session request payload.
3031 	 */
3032 	len = sizeof(req) - offsetof(struct rfc1002_session_packet, trailer.session_req);
3033 
3034 	smb_buf->smb_buf_length = cpu_to_be32((RFC1002_SESSION_REQUEST << 24) | len);
3035 	rc = smb_send(server, smb_buf, len);
3036 	/*
3037 	 * RFC1001 layer in at least one server requires very short break before
3038 	 * negprot presumably because not expecting negprot to follow so fast.
3039 	 * This is a simple solution that works without complicating the code
3040 	 * and causes no significant slowing down on mount for everyone else
3041 	 */
3042 	usleep_range(1000, 2000);
3043 
3044 	return rc;
3045 }
3046 
3047 static int
3048 generic_ip_connect(struct TCP_Server_Info *server)
3049 {
3050 	struct sockaddr *saddr;
3051 	struct socket *socket;
3052 	int slen, sfamily;
3053 	__be16 sport;
3054 	int rc = 0;
3055 
3056 	saddr = (struct sockaddr *) &server->dstaddr;
3057 
3058 	if (server->dstaddr.ss_family == AF_INET6) {
3059 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&server->dstaddr;
3060 
3061 		sport = ipv6->sin6_port;
3062 		slen = sizeof(struct sockaddr_in6);
3063 		sfamily = AF_INET6;
3064 		cifs_dbg(FYI, "%s: connecting to [%pI6]:%d\n", __func__, &ipv6->sin6_addr,
3065 				ntohs(sport));
3066 	} else {
3067 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)&server->dstaddr;
3068 
3069 		sport = ipv4->sin_port;
3070 		slen = sizeof(struct sockaddr_in);
3071 		sfamily = AF_INET;
3072 		cifs_dbg(FYI, "%s: connecting to %pI4:%d\n", __func__, &ipv4->sin_addr,
3073 				ntohs(sport));
3074 	}
3075 
3076 	if (server->ssocket) {
3077 		socket = server->ssocket;
3078 	} else {
3079 		rc = __sock_create(cifs_net_ns(server), sfamily, SOCK_STREAM,
3080 				   IPPROTO_TCP, &server->ssocket, 1);
3081 		if (rc < 0) {
3082 			cifs_server_dbg(VFS, "Error %d creating socket\n", rc);
3083 			return rc;
3084 		}
3085 
3086 		/* BB other socket options to set KEEPALIVE, NODELAY? */
3087 		cifs_dbg(FYI, "Socket created\n");
3088 		socket = server->ssocket;
3089 		socket->sk->sk_allocation = GFP_NOFS;
3090 		socket->sk->sk_use_task_frag = false;
3091 		if (sfamily == AF_INET6)
3092 			cifs_reclassify_socket6(socket);
3093 		else
3094 			cifs_reclassify_socket4(socket);
3095 	}
3096 
3097 	rc = bind_socket(server);
3098 	if (rc < 0)
3099 		return rc;
3100 
3101 	/*
3102 	 * Eventually check for other socket options to change from
3103 	 * the default. sock_setsockopt not used because it expects
3104 	 * user space buffer
3105 	 */
3106 	socket->sk->sk_rcvtimeo = 7 * HZ;
3107 	socket->sk->sk_sndtimeo = 5 * HZ;
3108 
3109 	/* make the bufsizes depend on wsize/rsize and max requests */
3110 	if (server->noautotune) {
3111 		if (socket->sk->sk_sndbuf < (200 * 1024))
3112 			socket->sk->sk_sndbuf = 200 * 1024;
3113 		if (socket->sk->sk_rcvbuf < (140 * 1024))
3114 			socket->sk->sk_rcvbuf = 140 * 1024;
3115 	}
3116 
3117 	if (server->tcp_nodelay)
3118 		tcp_sock_set_nodelay(socket->sk);
3119 
3120 	cifs_dbg(FYI, "sndbuf %d rcvbuf %d rcvtimeo 0x%lx\n",
3121 		 socket->sk->sk_sndbuf,
3122 		 socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
3123 
3124 	rc = kernel_connect(socket, saddr, slen,
3125 			    server->noblockcnt ? O_NONBLOCK : 0);
3126 	/*
3127 	 * When mounting SMB root file systems, we do not want to block in
3128 	 * connect. Otherwise bail out and then let cifs_reconnect() perform
3129 	 * reconnect failover - if possible.
3130 	 */
3131 	if (server->noblockcnt && rc == -EINPROGRESS)
3132 		rc = 0;
3133 	if (rc < 0) {
3134 		cifs_dbg(FYI, "Error %d connecting to server\n", rc);
3135 		trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
3136 		sock_release(socket);
3137 		server->ssocket = NULL;
3138 		return rc;
3139 	}
3140 	trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
3141 	if (sport == htons(RFC1001_PORT))
3142 		rc = ip_rfc1001_connect(server);
3143 
3144 	return rc;
3145 }
3146 
3147 static int
3148 ip_connect(struct TCP_Server_Info *server)
3149 {
3150 	__be16 *sport;
3151 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
3152 	struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
3153 
3154 	if (server->dstaddr.ss_family == AF_INET6)
3155 		sport = &addr6->sin6_port;
3156 	else
3157 		sport = &addr->sin_port;
3158 
3159 	if (*sport == 0) {
3160 		int rc;
3161 
3162 		/* try with 445 port at first */
3163 		*sport = htons(CIFS_PORT);
3164 
3165 		rc = generic_ip_connect(server);
3166 		if (rc >= 0)
3167 			return rc;
3168 
3169 		/* if it failed, try with 139 port */
3170 		*sport = htons(RFC1001_PORT);
3171 	}
3172 
3173 	return generic_ip_connect(server);
3174 }
3175 
3176 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
3177 void reset_cifs_unix_caps(unsigned int xid, struct cifs_tcon *tcon,
3178 			  struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3179 {
3180 	/*
3181 	 * If we are reconnecting then should we check to see if
3182 	 * any requested capabilities changed locally e.g. via
3183 	 * remount but we can not do much about it here
3184 	 * if they have (even if we could detect it by the following)
3185 	 * Perhaps we could add a backpointer to array of sb from tcon
3186 	 * or if we change to make all sb to same share the same
3187 	 * sb as NFS - then we only have one backpointer to sb.
3188 	 * What if we wanted to mount the server share twice once with
3189 	 * and once without posixacls or posix paths?
3190 	 */
3191 	__u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
3192 
3193 	if (ctx && ctx->no_linux_ext) {
3194 		tcon->fsUnixInfo.Capability = 0;
3195 		tcon->unix_ext = 0; /* Unix Extensions disabled */
3196 		cifs_dbg(FYI, "Linux protocol extensions disabled\n");
3197 		return;
3198 	} else if (ctx)
3199 		tcon->unix_ext = 1; /* Unix Extensions supported */
3200 
3201 	if (!tcon->unix_ext) {
3202 		cifs_dbg(FYI, "Unix extensions disabled so not set on reconnect\n");
3203 		return;
3204 	}
3205 
3206 	if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
3207 		__u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
3208 
3209 		cifs_dbg(FYI, "unix caps which server supports %lld\n", cap);
3210 		/*
3211 		 * check for reconnect case in which we do not
3212 		 * want to change the mount behavior if we can avoid it
3213 		 */
3214 		if (ctx == NULL) {
3215 			/*
3216 			 * turn off POSIX ACL and PATHNAMES if not set
3217 			 * originally at mount time
3218 			 */
3219 			if ((saved_cap & CIFS_UNIX_POSIX_ACL_CAP) == 0)
3220 				cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
3221 			if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
3222 				if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
3223 					cifs_dbg(VFS, "POSIXPATH support change\n");
3224 				cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
3225 			} else if ((cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
3226 				cifs_dbg(VFS, "possible reconnect error\n");
3227 				cifs_dbg(VFS, "server disabled POSIX path support\n");
3228 			}
3229 		}
3230 
3231 		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
3232 			cifs_dbg(VFS, "per-share encryption not supported yet\n");
3233 
3234 		cap &= CIFS_UNIX_CAP_MASK;
3235 		if (ctx && ctx->no_psx_acl)
3236 			cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
3237 		else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
3238 			cifs_dbg(FYI, "negotiated posix acl support\n");
3239 			if (cifs_sb)
3240 				cifs_sb->mnt_cifs_flags |=
3241 					CIFS_MOUNT_POSIXACL;
3242 		}
3243 
3244 		if (ctx && ctx->posix_paths == 0)
3245 			cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
3246 		else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
3247 			cifs_dbg(FYI, "negotiate posix pathnames\n");
3248 			if (cifs_sb)
3249 				cifs_sb->mnt_cifs_flags |=
3250 					CIFS_MOUNT_POSIX_PATHS;
3251 		}
3252 
3253 		cifs_dbg(FYI, "Negotiate caps 0x%x\n", (int)cap);
3254 #ifdef CONFIG_CIFS_DEBUG2
3255 		if (cap & CIFS_UNIX_FCNTL_CAP)
3256 			cifs_dbg(FYI, "FCNTL cap\n");
3257 		if (cap & CIFS_UNIX_EXTATTR_CAP)
3258 			cifs_dbg(FYI, "EXTATTR cap\n");
3259 		if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
3260 			cifs_dbg(FYI, "POSIX path cap\n");
3261 		if (cap & CIFS_UNIX_XATTR_CAP)
3262 			cifs_dbg(FYI, "XATTR cap\n");
3263 		if (cap & CIFS_UNIX_POSIX_ACL_CAP)
3264 			cifs_dbg(FYI, "POSIX ACL cap\n");
3265 		if (cap & CIFS_UNIX_LARGE_READ_CAP)
3266 			cifs_dbg(FYI, "very large read cap\n");
3267 		if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
3268 			cifs_dbg(FYI, "very large write cap\n");
3269 		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
3270 			cifs_dbg(FYI, "transport encryption cap\n");
3271 		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
3272 			cifs_dbg(FYI, "mandatory transport encryption cap\n");
3273 #endif /* CIFS_DEBUG2 */
3274 		if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
3275 			if (ctx == NULL)
3276 				cifs_dbg(FYI, "resetting capabilities failed\n");
3277 			else
3278 				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");
3279 
3280 		}
3281 	}
3282 }
3283 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
3284 
3285 int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb)
3286 {
3287 	struct smb3_fs_context *ctx = cifs_sb->ctx;
3288 
3289 	INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
3290 
3291 	spin_lock_init(&cifs_sb->tlink_tree_lock);
3292 	cifs_sb->tlink_tree = RB_ROOT;
3293 
3294 	cifs_dbg(FYI, "file mode: %04ho  dir mode: %04ho\n",
3295 		 ctx->file_mode, ctx->dir_mode);
3296 
3297 	/* this is needed for ASCII cp to Unicode converts */
3298 	if (ctx->iocharset == NULL) {
3299 		/* load_nls_default cannot return null */
3300 		cifs_sb->local_nls = load_nls_default();
3301 	} else {
3302 		cifs_sb->local_nls = load_nls(ctx->iocharset);
3303 		if (cifs_sb->local_nls == NULL) {
3304 			cifs_dbg(VFS, "CIFS mount error: iocharset %s not found\n",
3305 				 ctx->iocharset);
3306 			return -ELIBACC;
3307 		}
3308 	}
3309 	ctx->local_nls = cifs_sb->local_nls;
3310 
3311 	smb3_update_mnt_flags(cifs_sb);
3312 
3313 	if (ctx->direct_io)
3314 		cifs_dbg(FYI, "mounting share using direct i/o\n");
3315 	if (ctx->cache_ro) {
3316 		cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
3317 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
3318 	} else if (ctx->cache_rw) {
3319 		cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
3320 		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
3321 					    CIFS_MOUNT_RW_CACHE);
3322 	}
3323 
3324 	if ((ctx->cifs_acl) && (ctx->dynperm))
3325 		cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
3326 
3327 	if (ctx->prepath) {
3328 		cifs_sb->prepath = kstrdup(ctx->prepath, GFP_KERNEL);
3329 		if (cifs_sb->prepath == NULL)
3330 			return -ENOMEM;
3331 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3332 	}
3333 
3334 	return 0;
3335 }
3336 
3337 /* Release all succeed connections */
3338 void cifs_mount_put_conns(struct cifs_mount_ctx *mnt_ctx)
3339 {
3340 	int rc = 0;
3341 
3342 	if (mnt_ctx->tcon)
3343 		cifs_put_tcon(mnt_ctx->tcon, netfs_trace_tcon_ref_put_mnt_ctx);
3344 	else if (mnt_ctx->ses)
3345 		cifs_put_smb_ses(mnt_ctx->ses);
3346 	else if (mnt_ctx->server)
3347 		cifs_put_tcp_session(mnt_ctx->server, 0);
3348 	mnt_ctx->ses = NULL;
3349 	mnt_ctx->tcon = NULL;
3350 	mnt_ctx->server = NULL;
3351 	mnt_ctx->cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
3352 	free_xid(mnt_ctx->xid);
3353 }
3354 
3355 int cifs_mount_get_session(struct cifs_mount_ctx *mnt_ctx)
3356 {
3357 	struct TCP_Server_Info *server = NULL;
3358 	struct smb3_fs_context *ctx;
3359 	struct cifs_ses *ses = NULL;
3360 	unsigned int xid;
3361 	int rc = 0;
3362 
3363 	xid = get_xid();
3364 
3365 	if (WARN_ON_ONCE(!mnt_ctx || !mnt_ctx->fs_ctx)) {
3366 		rc = -EINVAL;
3367 		goto out;
3368 	}
3369 	ctx = mnt_ctx->fs_ctx;
3370 
3371 	/* get a reference to a tcp session */
3372 	server = cifs_get_tcp_session(ctx, NULL);
3373 	if (IS_ERR(server)) {
3374 		rc = PTR_ERR(server);
3375 		server = NULL;
3376 		goto out;
3377 	}
3378 
3379 	/* get a reference to a SMB session */
3380 	ses = cifs_get_smb_ses(server, ctx);
3381 	if (IS_ERR(ses)) {
3382 		rc = PTR_ERR(ses);
3383 		ses = NULL;
3384 		goto out;
3385 	}
3386 
3387 	if ((ctx->persistent == true) && (!(ses->server->capabilities &
3388 					    SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
3389 		cifs_server_dbg(VFS, "persistent handles not supported by server\n");
3390 		rc = -EOPNOTSUPP;
3391 	}
3392 
3393 out:
3394 	mnt_ctx->xid = xid;
3395 	mnt_ctx->server = server;
3396 	mnt_ctx->ses = ses;
3397 	mnt_ctx->tcon = NULL;
3398 
3399 	return rc;
3400 }
3401 
3402 int cifs_mount_get_tcon(struct cifs_mount_ctx *mnt_ctx)
3403 {
3404 	struct TCP_Server_Info *server;
3405 	struct cifs_sb_info *cifs_sb;
3406 	struct smb3_fs_context *ctx;
3407 	struct cifs_tcon *tcon = NULL;
3408 	int rc = 0;
3409 
3410 	if (WARN_ON_ONCE(!mnt_ctx || !mnt_ctx->server || !mnt_ctx->ses || !mnt_ctx->fs_ctx ||
3411 			 !mnt_ctx->cifs_sb)) {
3412 		rc = -EINVAL;
3413 		goto out;
3414 	}
3415 	server = mnt_ctx->server;
3416 	ctx = mnt_ctx->fs_ctx;
3417 	cifs_sb = mnt_ctx->cifs_sb;
3418 
3419 	/* search for existing tcon to this server share */
3420 	tcon = cifs_get_tcon(mnt_ctx->ses, ctx);
3421 	if (IS_ERR(tcon)) {
3422 		rc = PTR_ERR(tcon);
3423 		tcon = NULL;
3424 		goto out;
3425 	}
3426 
3427 	/* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
3428 	if (tcon->posix_extensions)
3429 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
3430 
3431 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
3432 	/* tell server which Unix caps we support */
3433 	if (cap_unix(tcon->ses)) {
3434 		/*
3435 		 * reset of caps checks mount to see if unix extensions disabled
3436 		 * for just this mount.
3437 		 */
3438 		reset_cifs_unix_caps(mnt_ctx->xid, tcon, cifs_sb, ctx);
3439 		spin_lock(&tcon->ses->server->srv_lock);
3440 		if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
3441 		    (le64_to_cpu(tcon->fsUnixInfo.Capability) &
3442 		     CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
3443 			spin_unlock(&tcon->ses->server->srv_lock);
3444 			rc = -EACCES;
3445 			goto out;
3446 		}
3447 		spin_unlock(&tcon->ses->server->srv_lock);
3448 	} else
3449 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
3450 		tcon->unix_ext = 0; /* server does not support them */
3451 
3452 	/* do not care if a following call succeed - informational */
3453 	if (!tcon->pipe && server->ops->qfs_tcon) {
3454 		server->ops->qfs_tcon(mnt_ctx->xid, tcon, cifs_sb);
3455 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE) {
3456 			if (tcon->fsDevInfo.DeviceCharacteristics &
3457 			    cpu_to_le32(FILE_READ_ONLY_DEVICE))
3458 				cifs_dbg(VFS, "mounted to read only share\n");
3459 			else if ((cifs_sb->mnt_cifs_flags &
3460 				  CIFS_MOUNT_RW_CACHE) == 0)
3461 				cifs_dbg(VFS, "read only mount of RW share\n");
3462 			/* no need to log a RW mount of a typical RW share */
3463 		}
3464 	}
3465 
3466 	/*
3467 	 * Clamp the rsize/wsize mount arguments if they are too big for the server
3468 	 * and set the rsize/wsize to the negotiated values if not passed in by
3469 	 * the user on mount
3470 	 */
3471 	if ((cifs_sb->ctx->wsize == 0) ||
3472 	    (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx))) {
3473 		cifs_sb->ctx->wsize =
3474 			round_down(server->ops->negotiate_wsize(tcon, ctx), PAGE_SIZE);
3475 		/*
3476 		 * in the very unlikely event that the server sent a max write size under PAGE_SIZE,
3477 		 * (which would get rounded down to 0) then reset wsize to absolute minimum eg 4096
3478 		 */
3479 		if (cifs_sb->ctx->wsize == 0) {
3480 			cifs_sb->ctx->wsize = PAGE_SIZE;
3481 			cifs_dbg(VFS, "wsize too small, reset to minimum ie PAGE_SIZE, usually 4096\n");
3482 		}
3483 	}
3484 	if ((cifs_sb->ctx->rsize == 0) ||
3485 	    (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
3486 		cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
3487 
3488 	/*
3489 	 * The cookie is initialized from volume info returned above.
3490 	 * Inside cifs_fscache_get_super_cookie it checks
3491 	 * that we do not get super cookie twice.
3492 	 */
3493 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE)
3494 		cifs_fscache_get_super_cookie(tcon);
3495 
3496 out:
3497 	mnt_ctx->tcon = tcon;
3498 	return rc;
3499 }
3500 
3501 static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
3502 			     struct cifs_tcon *tcon)
3503 {
3504 	struct tcon_link *tlink;
3505 
3506 	/* hang the tcon off of the superblock */
3507 	tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
3508 	if (tlink == NULL)
3509 		return -ENOMEM;
3510 
3511 	tlink->tl_uid = ses->linux_uid;
3512 	tlink->tl_tcon = tcon;
3513 	tlink->tl_time = jiffies;
3514 	set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
3515 	set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3516 
3517 	cifs_sb->master_tlink = tlink;
3518 	spin_lock(&cifs_sb->tlink_tree_lock);
3519 	tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
3520 	spin_unlock(&cifs_sb->tlink_tree_lock);
3521 
3522 	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
3523 				TLINK_IDLE_EXPIRE);
3524 	return 0;
3525 }
3526 
3527 static int
3528 cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
3529 					unsigned int xid,
3530 					struct cifs_tcon *tcon,
3531 					struct cifs_sb_info *cifs_sb,
3532 					char *full_path,
3533 					int added_treename)
3534 {
3535 	int rc;
3536 	char *s;
3537 	char sep, tmp;
3538 	int skip = added_treename ? 1 : 0;
3539 
3540 	sep = CIFS_DIR_SEP(cifs_sb);
3541 	s = full_path;
3542 
3543 	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
3544 	while (rc == 0) {
3545 		/* skip separators */
3546 		while (*s == sep)
3547 			s++;
3548 		if (!*s)
3549 			break;
3550 		/* next separator */
3551 		while (*s && *s != sep)
3552 			s++;
3553 		/*
3554 		 * if the treename is added, we then have to skip the first
3555 		 * part within the separators
3556 		 */
3557 		if (skip) {
3558 			skip = 0;
3559 			continue;
3560 		}
3561 		/*
3562 		 * temporarily null-terminate the path at the end of
3563 		 * the current component
3564 		 */
3565 		tmp = *s;
3566 		*s = 0;
3567 		rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3568 						     full_path);
3569 		*s = tmp;
3570 	}
3571 	return rc;
3572 }
3573 
3574 /*
3575  * Check if path is remote (i.e. a DFS share).
3576  *
3577  * Return -EREMOTE if it is, otherwise 0 or -errno.
3578  */
3579 int cifs_is_path_remote(struct cifs_mount_ctx *mnt_ctx)
3580 {
3581 	int rc;
3582 	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3583 	struct TCP_Server_Info *server = mnt_ctx->server;
3584 	unsigned int xid = mnt_ctx->xid;
3585 	struct cifs_tcon *tcon = mnt_ctx->tcon;
3586 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3587 	char *full_path;
3588 
3589 	if (!server->ops->is_path_accessible)
3590 		return -EOPNOTSUPP;
3591 
3592 	/*
3593 	 * cifs_build_path_to_root works only when we have a valid tcon
3594 	 */
3595 	full_path = cifs_build_path_to_root(ctx, cifs_sb, tcon,
3596 					    tcon->Flags & SMB_SHARE_IS_IN_DFS);
3597 	if (full_path == NULL)
3598 		return -ENOMEM;
3599 
3600 	cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
3601 
3602 	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3603 					     full_path);
3604 	if (rc != 0 && rc != -EREMOTE)
3605 		goto out;
3606 
3607 	if (rc != -EREMOTE) {
3608 		rc = cifs_are_all_path_components_accessible(server, xid, tcon,
3609 			cifs_sb, full_path, tcon->Flags & SMB_SHARE_IS_IN_DFS);
3610 		if (rc != 0) {
3611 			cifs_server_dbg(VFS, "cannot query dirs between root and final path, enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
3612 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3613 			rc = 0;
3614 		}
3615 	}
3616 
3617 out:
3618 	kfree(full_path);
3619 	return rc;
3620 }
3621 
3622 #ifdef CONFIG_CIFS_DFS_UPCALL
3623 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3624 {
3625 	struct cifs_mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
3626 	bool isdfs;
3627 	int rc;
3628 
3629 	rc = dfs_mount_share(&mnt_ctx, &isdfs);
3630 	if (rc)
3631 		goto error;
3632 	if (!isdfs)
3633 		goto out;
3634 
3635 	/*
3636 	 * After reconnecting to a different server, unique ids won't match anymore, so we disable
3637 	 * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
3638 	 */
3639 	cifs_autodisable_serverino(cifs_sb);
3640 	/*
3641 	 * Force the use of prefix path to support failover on DFS paths that resolve to targets
3642 	 * that have different prefix paths.
3643 	 */
3644 	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3645 	kfree(cifs_sb->prepath);
3646 	cifs_sb->prepath = ctx->prepath;
3647 	ctx->prepath = NULL;
3648 
3649 out:
3650 	cifs_try_adding_channels(mnt_ctx.ses);
3651 	rc = mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
3652 	if (rc)
3653 		goto error;
3654 
3655 	free_xid(mnt_ctx.xid);
3656 	return rc;
3657 
3658 error:
3659 	cifs_mount_put_conns(&mnt_ctx);
3660 	return rc;
3661 }
3662 #else
3663 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3664 {
3665 	int rc = 0;
3666 	struct cifs_mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
3667 
3668 	rc = cifs_mount_get_session(&mnt_ctx);
3669 	if (rc)
3670 		goto error;
3671 
3672 	rc = cifs_mount_get_tcon(&mnt_ctx);
3673 	if (!rc) {
3674 		/*
3675 		 * Prevent superblock from being created with any missing
3676 		 * connections.
3677 		 */
3678 		if (WARN_ON(!mnt_ctx.server))
3679 			rc = -EHOSTDOWN;
3680 		else if (WARN_ON(!mnt_ctx.ses))
3681 			rc = -EACCES;
3682 		else if (WARN_ON(!mnt_ctx.tcon))
3683 			rc = -ENOENT;
3684 	}
3685 	if (rc)
3686 		goto error;
3687 
3688 	rc = cifs_is_path_remote(&mnt_ctx);
3689 	if (rc == -EREMOTE)
3690 		rc = -EOPNOTSUPP;
3691 	if (rc)
3692 		goto error;
3693 
3694 	rc = mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
3695 	if (rc)
3696 		goto error;
3697 
3698 	free_xid(mnt_ctx.xid);
3699 	return rc;
3700 
3701 error:
3702 	cifs_mount_put_conns(&mnt_ctx);
3703 	return rc;
3704 }
3705 #endif
3706 
3707 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
3708 /*
3709  * Issue a TREE_CONNECT request.
3710  */
3711 int
3712 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
3713 	 const char *tree, struct cifs_tcon *tcon,
3714 	 const struct nls_table *nls_codepage)
3715 {
3716 	struct smb_hdr *smb_buffer;
3717 	struct smb_hdr *smb_buffer_response;
3718 	TCONX_REQ *pSMB;
3719 	TCONX_RSP *pSMBr;
3720 	unsigned char *bcc_ptr;
3721 	int rc = 0;
3722 	int length;
3723 	__u16 bytes_left, count;
3724 
3725 	if (ses == NULL)
3726 		return -EIO;
3727 
3728 	smb_buffer = cifs_buf_get();
3729 	if (smb_buffer == NULL)
3730 		return -ENOMEM;
3731 
3732 	smb_buffer_response = smb_buffer;
3733 
3734 	header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
3735 			NULL /*no tid */, 4 /*wct */);
3736 
3737 	smb_buffer->Mid = get_next_mid(ses->server);
3738 	smb_buffer->Uid = ses->Suid;
3739 	pSMB = (TCONX_REQ *) smb_buffer;
3740 	pSMBr = (TCONX_RSP *) smb_buffer_response;
3741 
3742 	pSMB->AndXCommand = 0xFF;
3743 	pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
3744 	bcc_ptr = &pSMB->Password[0];
3745 
3746 	pSMB->PasswordLength = cpu_to_le16(1);	/* minimum */
3747 	*bcc_ptr = 0; /* password is null byte */
3748 	bcc_ptr++;              /* skip password */
3749 	/* already aligned so no need to do it below */
3750 
3751 	if (ses->server->sign)
3752 		smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
3753 
3754 	if (ses->capabilities & CAP_STATUS32)
3755 		smb_buffer->Flags2 |= SMBFLG2_ERR_STATUS;
3756 
3757 	if (ses->capabilities & CAP_DFS)
3758 		smb_buffer->Flags2 |= SMBFLG2_DFS;
3759 
3760 	if (ses->capabilities & CAP_UNICODE) {
3761 		smb_buffer->Flags2 |= SMBFLG2_UNICODE;
3762 		length =
3763 		    cifs_strtoUTF16((__le16 *) bcc_ptr, tree,
3764 			6 /* max utf8 char length in bytes */ *
3765 			(/* server len*/ + 256 /* share len */), nls_codepage);
3766 		bcc_ptr += 2 * length;	/* convert num 16 bit words to bytes */
3767 		bcc_ptr += 2;	/* skip trailing null */
3768 	} else {		/* ASCII */
3769 		strcpy(bcc_ptr, tree);
3770 		bcc_ptr += strlen(tree) + 1;
3771 	}
3772 	strcpy(bcc_ptr, "?????");
3773 	bcc_ptr += strlen("?????");
3774 	bcc_ptr += 1;
3775 	count = bcc_ptr - &pSMB->Password[0];
3776 	be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
3777 	pSMB->ByteCount = cpu_to_le16(count);
3778 
3779 	rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,
3780 			 0);
3781 
3782 	/* above now done in SendReceive */
3783 	if (rc == 0) {
3784 		bool is_unicode;
3785 
3786 		tcon->tid = smb_buffer_response->Tid;
3787 		bcc_ptr = pByteArea(smb_buffer_response);
3788 		bytes_left = get_bcc(smb_buffer_response);
3789 		length = strnlen(bcc_ptr, bytes_left - 2);
3790 		if (smb_buffer->Flags2 & SMBFLG2_UNICODE)
3791 			is_unicode = true;
3792 		else
3793 			is_unicode = false;
3794 
3795 
3796 		/* skip service field (NB: this field is always ASCII) */
3797 		if (length == 3) {
3798 			if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
3799 			    (bcc_ptr[2] == 'C')) {
3800 				cifs_dbg(FYI, "IPC connection\n");
3801 				tcon->ipc = true;
3802 				tcon->pipe = true;
3803 			}
3804 		} else if (length == 2) {
3805 			if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
3806 				/* the most common case */
3807 				cifs_dbg(FYI, "disk share connection\n");
3808 			}
3809 		}
3810 		bcc_ptr += length + 1;
3811 		bytes_left -= (length + 1);
3812 		strscpy(tcon->tree_name, tree, sizeof(tcon->tree_name));
3813 
3814 		/* mostly informational -- no need to fail on error here */
3815 		kfree(tcon->nativeFileSystem);
3816 		tcon->nativeFileSystem = cifs_strndup_from_utf16(bcc_ptr,
3817 						      bytes_left, is_unicode,
3818 						      nls_codepage);
3819 
3820 		cifs_dbg(FYI, "nativeFileSystem=%s\n", tcon->nativeFileSystem);
3821 
3822 		if ((smb_buffer_response->WordCount == 3) ||
3823 			 (smb_buffer_response->WordCount == 7))
3824 			/* field is in same location */
3825 			tcon->Flags = le16_to_cpu(pSMBr->OptionalSupport);
3826 		else
3827 			tcon->Flags = 0;
3828 		cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
3829 
3830 		/*
3831 		 * reset_cifs_unix_caps calls QFSInfo which requires
3832 		 * need_reconnect to be false, but we would not need to call
3833 		 * reset_caps if this were not a reconnect case so must check
3834 		 * need_reconnect flag here.  The caller will also clear
3835 		 * need_reconnect when tcon was successful but needed to be
3836 		 * cleared earlier in the case of unix extensions reconnect
3837 		 */
3838 		if (tcon->need_reconnect && tcon->unix_ext) {
3839 			cifs_dbg(FYI, "resetting caps for %s\n", tcon->tree_name);
3840 			tcon->need_reconnect = false;
3841 			reset_cifs_unix_caps(xid, tcon, NULL, NULL);
3842 		}
3843 	}
3844 	cifs_buf_release(smb_buffer);
3845 	return rc;
3846 }
3847 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
3848 
3849 static void delayed_free(struct rcu_head *p)
3850 {
3851 	struct cifs_sb_info *cifs_sb = container_of(p, struct cifs_sb_info, rcu);
3852 
3853 	unload_nls(cifs_sb->local_nls);
3854 	smb3_cleanup_fs_context(cifs_sb->ctx);
3855 	kfree(cifs_sb);
3856 }
3857 
3858 void
3859 cifs_umount(struct cifs_sb_info *cifs_sb)
3860 {
3861 	struct rb_root *root = &cifs_sb->tlink_tree;
3862 	struct rb_node *node;
3863 	struct tcon_link *tlink;
3864 
3865 	cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
3866 
3867 	spin_lock(&cifs_sb->tlink_tree_lock);
3868 	while ((node = rb_first(root))) {
3869 		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
3870 		cifs_get_tlink(tlink);
3871 		clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3872 		rb_erase(node, root);
3873 
3874 		spin_unlock(&cifs_sb->tlink_tree_lock);
3875 		cifs_put_tlink(tlink);
3876 		spin_lock(&cifs_sb->tlink_tree_lock);
3877 	}
3878 	spin_unlock(&cifs_sb->tlink_tree_lock);
3879 
3880 	kfree(cifs_sb->prepath);
3881 	call_rcu(&cifs_sb->rcu, delayed_free);
3882 }
3883 
3884 int
3885 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses,
3886 			struct TCP_Server_Info *server)
3887 {
3888 	int rc = 0;
3889 
3890 	if (!server->ops->need_neg || !server->ops->negotiate)
3891 		return -ENOSYS;
3892 
3893 	/* only send once per connect */
3894 	spin_lock(&server->srv_lock);
3895 	if (server->tcpStatus != CifsGood &&
3896 	    server->tcpStatus != CifsNew &&
3897 	    server->tcpStatus != CifsNeedNegotiate) {
3898 		spin_unlock(&server->srv_lock);
3899 		return -EHOSTDOWN;
3900 	}
3901 
3902 	if (!server->ops->need_neg(server) &&
3903 	    server->tcpStatus == CifsGood) {
3904 		spin_unlock(&server->srv_lock);
3905 		return 0;
3906 	}
3907 
3908 	server->tcpStatus = CifsInNegotiate;
3909 	spin_unlock(&server->srv_lock);
3910 
3911 	rc = server->ops->negotiate(xid, ses, server);
3912 	if (rc == 0) {
3913 		spin_lock(&server->srv_lock);
3914 		if (server->tcpStatus == CifsInNegotiate)
3915 			server->tcpStatus = CifsGood;
3916 		else
3917 			rc = -EHOSTDOWN;
3918 		spin_unlock(&server->srv_lock);
3919 	} else {
3920 		spin_lock(&server->srv_lock);
3921 		if (server->tcpStatus == CifsInNegotiate)
3922 			server->tcpStatus = CifsNeedNegotiate;
3923 		spin_unlock(&server->srv_lock);
3924 	}
3925 
3926 	return rc;
3927 }
3928 
3929 int
3930 cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
3931 		   struct TCP_Server_Info *server,
3932 		   struct nls_table *nls_info)
3933 {
3934 	int rc = -ENOSYS;
3935 	struct TCP_Server_Info *pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
3936 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&pserver->dstaddr;
3937 	struct sockaddr_in *addr = (struct sockaddr_in *)&pserver->dstaddr;
3938 	bool is_binding = false;
3939 
3940 	spin_lock(&ses->ses_lock);
3941 	cifs_dbg(FYI, "%s: channel connect bitmap: 0x%lx\n",
3942 		 __func__, ses->chans_need_reconnect);
3943 
3944 	if (ses->ses_status != SES_GOOD &&
3945 	    ses->ses_status != SES_NEW &&
3946 	    ses->ses_status != SES_NEED_RECON) {
3947 		spin_unlock(&ses->ses_lock);
3948 		return -EHOSTDOWN;
3949 	}
3950 
3951 	/* only send once per connect */
3952 	spin_lock(&ses->chan_lock);
3953 	if (CIFS_ALL_CHANS_GOOD(ses)) {
3954 		if (ses->ses_status == SES_NEED_RECON)
3955 			ses->ses_status = SES_GOOD;
3956 		spin_unlock(&ses->chan_lock);
3957 		spin_unlock(&ses->ses_lock);
3958 		return 0;
3959 	}
3960 
3961 	cifs_chan_set_in_reconnect(ses, server);
3962 	is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
3963 	spin_unlock(&ses->chan_lock);
3964 
3965 	if (!is_binding) {
3966 		ses->ses_status = SES_IN_SETUP;
3967 
3968 		/* force iface_list refresh */
3969 		ses->iface_last_update = 0;
3970 	}
3971 	spin_unlock(&ses->ses_lock);
3972 
3973 	/* update ses ip_addr only for primary chan */
3974 	if (server == pserver) {
3975 		if (server->dstaddr.ss_family == AF_INET6)
3976 			scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI6", &addr6->sin6_addr);
3977 		else
3978 			scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI4", &addr->sin_addr);
3979 	}
3980 
3981 	if (!is_binding) {
3982 		ses->capabilities = server->capabilities;
3983 		if (!linuxExtEnabled)
3984 			ses->capabilities &= (~server->vals->cap_unix);
3985 
3986 		if (ses->auth_key.response) {
3987 			cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
3988 				 ses->auth_key.response);
3989 			kfree_sensitive(ses->auth_key.response);
3990 			ses->auth_key.response = NULL;
3991 			ses->auth_key.len = 0;
3992 		}
3993 	}
3994 
3995 	cifs_dbg(FYI, "Security Mode: 0x%x Capabilities: 0x%x TimeAdjust: %d\n",
3996 		 server->sec_mode, server->capabilities, server->timeAdj);
3997 
3998 	if (server->ops->sess_setup)
3999 		rc = server->ops->sess_setup(xid, ses, server, nls_info);
4000 
4001 	if (rc) {
4002 		cifs_server_dbg(VFS, "Send error in SessSetup = %d\n", rc);
4003 		spin_lock(&ses->ses_lock);
4004 		if (ses->ses_status == SES_IN_SETUP)
4005 			ses->ses_status = SES_NEED_RECON;
4006 		spin_lock(&ses->chan_lock);
4007 		cifs_chan_clear_in_reconnect(ses, server);
4008 		spin_unlock(&ses->chan_lock);
4009 		spin_unlock(&ses->ses_lock);
4010 	} else {
4011 		spin_lock(&ses->ses_lock);
4012 		if (ses->ses_status == SES_IN_SETUP)
4013 			ses->ses_status = SES_GOOD;
4014 		spin_lock(&ses->chan_lock);
4015 		cifs_chan_clear_in_reconnect(ses, server);
4016 		cifs_chan_clear_need_reconnect(ses, server);
4017 		spin_unlock(&ses->chan_lock);
4018 		spin_unlock(&ses->ses_lock);
4019 	}
4020 
4021 	return rc;
4022 }
4023 
4024 static int
4025 cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
4026 {
4027 	ctx->sectype = ses->sectype;
4028 
4029 	/* krb5 is special, since we don't need username or pw */
4030 	if (ctx->sectype == Kerberos)
4031 		return 0;
4032 
4033 	return cifs_set_cifscreds(ctx, ses);
4034 }
4035 
4036 static struct cifs_tcon *
4037 __cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
4038 {
4039 	int rc;
4040 	struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
4041 	struct cifs_ses *ses;
4042 	struct cifs_tcon *tcon = NULL;
4043 	struct smb3_fs_context *ctx;
4044 	char *origin_fullpath = NULL;
4045 
4046 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
4047 	if (ctx == NULL)
4048 		return ERR_PTR(-ENOMEM);
4049 
4050 	ctx->local_nls = cifs_sb->local_nls;
4051 	ctx->linux_uid = fsuid;
4052 	ctx->cred_uid = fsuid;
4053 	ctx->UNC = master_tcon->tree_name;
4054 	ctx->retry = master_tcon->retry;
4055 	ctx->nocase = master_tcon->nocase;
4056 	ctx->nohandlecache = master_tcon->nohandlecache;
4057 	ctx->local_lease = master_tcon->local_lease;
4058 	ctx->no_lease = master_tcon->no_lease;
4059 	ctx->resilient = master_tcon->use_resilient;
4060 	ctx->persistent = master_tcon->use_persistent;
4061 	ctx->handle_timeout = master_tcon->handle_timeout;
4062 	ctx->no_linux_ext = !master_tcon->unix_ext;
4063 	ctx->linux_ext = master_tcon->posix_extensions;
4064 	ctx->sectype = master_tcon->ses->sectype;
4065 	ctx->sign = master_tcon->ses->sign;
4066 	ctx->seal = master_tcon->seal;
4067 	ctx->witness = master_tcon->use_witness;
4068 	ctx->dfs_root_ses = master_tcon->ses->dfs_root_ses;
4069 
4070 	rc = cifs_set_vol_auth(ctx, master_tcon->ses);
4071 	if (rc) {
4072 		tcon = ERR_PTR(rc);
4073 		goto out;
4074 	}
4075 
4076 	/* get a reference for the same TCP session */
4077 	spin_lock(&cifs_tcp_ses_lock);
4078 	++master_tcon->ses->server->srv_count;
4079 	spin_unlock(&cifs_tcp_ses_lock);
4080 
4081 	ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
4082 	if (IS_ERR(ses)) {
4083 		tcon = ERR_CAST(ses);
4084 		cifs_put_tcp_session(master_tcon->ses->server, 0);
4085 		goto out;
4086 	}
4087 
4088 #ifdef CONFIG_CIFS_DFS_UPCALL
4089 	spin_lock(&master_tcon->tc_lock);
4090 	if (master_tcon->origin_fullpath) {
4091 		spin_unlock(&master_tcon->tc_lock);
4092 		origin_fullpath = dfs_get_path(cifs_sb, cifs_sb->ctx->source);
4093 		if (IS_ERR(origin_fullpath)) {
4094 			tcon = ERR_CAST(origin_fullpath);
4095 			origin_fullpath = NULL;
4096 			cifs_put_smb_ses(ses);
4097 			goto out;
4098 		}
4099 	} else {
4100 		spin_unlock(&master_tcon->tc_lock);
4101 	}
4102 #endif
4103 
4104 	tcon = cifs_get_tcon(ses, ctx);
4105 	if (IS_ERR(tcon)) {
4106 		cifs_put_smb_ses(ses);
4107 		goto out;
4108 	}
4109 
4110 #ifdef CONFIG_CIFS_DFS_UPCALL
4111 	if (origin_fullpath) {
4112 		spin_lock(&tcon->tc_lock);
4113 		tcon->origin_fullpath = origin_fullpath;
4114 		spin_unlock(&tcon->tc_lock);
4115 		origin_fullpath = NULL;
4116 		queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
4117 				   dfs_cache_get_ttl() * HZ);
4118 	}
4119 #endif
4120 
4121 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
4122 	if (cap_unix(ses))
4123 		reset_cifs_unix_caps(0, tcon, NULL, ctx);
4124 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
4125 
4126 out:
4127 	kfree(ctx->username);
4128 	kfree_sensitive(ctx->password);
4129 	kfree(origin_fullpath);
4130 	kfree(ctx);
4131 
4132 	return tcon;
4133 }
4134 
4135 static struct cifs_tcon *
4136 cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
4137 {
4138 	struct cifs_tcon *ret;
4139 
4140 	cifs_mount_lock();
4141 	ret = __cifs_construct_tcon(cifs_sb, fsuid);
4142 	cifs_mount_unlock();
4143 	return ret;
4144 }
4145 
4146 struct cifs_tcon *
4147 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
4148 {
4149 	return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
4150 }
4151 
4152 /* find and return a tlink with given uid */
4153 static struct tcon_link *
4154 tlink_rb_search(struct rb_root *root, kuid_t uid)
4155 {
4156 	struct rb_node *node = root->rb_node;
4157 	struct tcon_link *tlink;
4158 
4159 	while (node) {
4160 		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
4161 
4162 		if (uid_gt(tlink->tl_uid, uid))
4163 			node = node->rb_left;
4164 		else if (uid_lt(tlink->tl_uid, uid))
4165 			node = node->rb_right;
4166 		else
4167 			return tlink;
4168 	}
4169 	return NULL;
4170 }
4171 
4172 /* insert a tcon_link into the tree */
4173 static void
4174 tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
4175 {
4176 	struct rb_node **new = &(root->rb_node), *parent = NULL;
4177 	struct tcon_link *tlink;
4178 
4179 	while (*new) {
4180 		tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
4181 		parent = *new;
4182 
4183 		if (uid_gt(tlink->tl_uid, new_tlink->tl_uid))
4184 			new = &((*new)->rb_left);
4185 		else
4186 			new = &((*new)->rb_right);
4187 	}
4188 
4189 	rb_link_node(&new_tlink->tl_rbnode, parent, new);
4190 	rb_insert_color(&new_tlink->tl_rbnode, root);
4191 }
4192 
4193 /*
4194  * Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
4195  * current task.
4196  *
4197  * If the superblock doesn't refer to a multiuser mount, then just return
4198  * the master tcon for the mount.
4199  *
4200  * First, search the rbtree for an existing tcon for this fsuid. If one
4201  * exists, then check to see if it's pending construction. If it is then wait
4202  * for construction to complete. Once it's no longer pending, check to see if
4203  * it failed and either return an error or retry construction, depending on
4204  * the timeout.
4205  *
4206  * If one doesn't exist then insert a new tcon_link struct into the tree and
4207  * try to construct a new one.
4208  *
4209  * REMEMBER to call cifs_put_tlink() after successful calls to cifs_sb_tlink,
4210  * to avoid refcount issues
4211  */
4212 struct tcon_link *
4213 cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
4214 {
4215 	int ret;
4216 	kuid_t fsuid = current_fsuid();
4217 	struct tcon_link *tlink, *newtlink;
4218 
4219 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
4220 		return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
4221 
4222 	spin_lock(&cifs_sb->tlink_tree_lock);
4223 	tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4224 	if (tlink)
4225 		cifs_get_tlink(tlink);
4226 	spin_unlock(&cifs_sb->tlink_tree_lock);
4227 
4228 	if (tlink == NULL) {
4229 		newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
4230 		if (newtlink == NULL)
4231 			return ERR_PTR(-ENOMEM);
4232 		newtlink->tl_uid = fsuid;
4233 		newtlink->tl_tcon = ERR_PTR(-EACCES);
4234 		set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
4235 		set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
4236 		cifs_get_tlink(newtlink);
4237 
4238 		spin_lock(&cifs_sb->tlink_tree_lock);
4239 		/* was one inserted after previous search? */
4240 		tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4241 		if (tlink) {
4242 			cifs_get_tlink(tlink);
4243 			spin_unlock(&cifs_sb->tlink_tree_lock);
4244 			kfree(newtlink);
4245 			goto wait_for_construction;
4246 		}
4247 		tlink = newtlink;
4248 		tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
4249 		spin_unlock(&cifs_sb->tlink_tree_lock);
4250 	} else {
4251 wait_for_construction:
4252 		ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
4253 				  TASK_INTERRUPTIBLE);
4254 		if (ret) {
4255 			cifs_put_tlink(tlink);
4256 			return ERR_PTR(-ERESTARTSYS);
4257 		}
4258 
4259 		/* if it's good, return it */
4260 		if (!IS_ERR(tlink->tl_tcon))
4261 			return tlink;
4262 
4263 		/* return error if we tried this already recently */
4264 		if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
4265 			cifs_put_tlink(tlink);
4266 			return ERR_PTR(-EACCES);
4267 		}
4268 
4269 		if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
4270 			goto wait_for_construction;
4271 	}
4272 
4273 	tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid);
4274 	clear_bit(TCON_LINK_PENDING, &tlink->tl_flags);
4275 	wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
4276 
4277 	if (IS_ERR(tlink->tl_tcon)) {
4278 		cifs_put_tlink(tlink);
4279 		return ERR_PTR(-EACCES);
4280 	}
4281 
4282 	return tlink;
4283 }
4284 
4285 /*
4286  * periodic workqueue job that scans tcon_tree for a superblock and closes
4287  * out tcons.
4288  */
4289 static void
4290 cifs_prune_tlinks(struct work_struct *work)
4291 {
4292 	struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
4293 						    prune_tlinks.work);
4294 	struct rb_root *root = &cifs_sb->tlink_tree;
4295 	struct rb_node *node;
4296 	struct rb_node *tmp;
4297 	struct tcon_link *tlink;
4298 
4299 	/*
4300 	 * Because we drop the spinlock in the loop in order to put the tlink
4301 	 * it's not guarded against removal of links from the tree. The only
4302 	 * places that remove entries from the tree are this function and
4303 	 * umounts. Because this function is non-reentrant and is canceled
4304 	 * before umount can proceed, this is safe.
4305 	 */
4306 	spin_lock(&cifs_sb->tlink_tree_lock);
4307 	node = rb_first(root);
4308 	while (node != NULL) {
4309 		tmp = node;
4310 		node = rb_next(tmp);
4311 		tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
4312 
4313 		if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
4314 		    atomic_read(&tlink->tl_count) != 0 ||
4315 		    time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
4316 			continue;
4317 
4318 		cifs_get_tlink(tlink);
4319 		clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
4320 		rb_erase(tmp, root);
4321 
4322 		spin_unlock(&cifs_sb->tlink_tree_lock);
4323 		cifs_put_tlink(tlink);
4324 		spin_lock(&cifs_sb->tlink_tree_lock);
4325 	}
4326 	spin_unlock(&cifs_sb->tlink_tree_lock);
4327 
4328 	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
4329 				TLINK_IDLE_EXPIRE);
4330 }
4331 
4332 #ifndef CONFIG_CIFS_DFS_UPCALL
4333 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4334 {
4335 	int rc;
4336 	const struct smb_version_operations *ops = tcon->ses->server->ops;
4337 
4338 	/* only send once per connect */
4339 	spin_lock(&tcon->tc_lock);
4340 
4341 	/* if tcon is marked for needing reconnect, update state */
4342 	if (tcon->need_reconnect)
4343 		tcon->status = TID_NEED_TCON;
4344 
4345 	if (tcon->status == TID_GOOD) {
4346 		spin_unlock(&tcon->tc_lock);
4347 		return 0;
4348 	}
4349 
4350 	if (tcon->status != TID_NEW &&
4351 	    tcon->status != TID_NEED_TCON) {
4352 		spin_unlock(&tcon->tc_lock);
4353 		return -EHOSTDOWN;
4354 	}
4355 
4356 	tcon->status = TID_IN_TCON;
4357 	spin_unlock(&tcon->tc_lock);
4358 
4359 	rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon, nlsc);
4360 	if (rc) {
4361 		spin_lock(&tcon->tc_lock);
4362 		if (tcon->status == TID_IN_TCON)
4363 			tcon->status = TID_NEED_TCON;
4364 		spin_unlock(&tcon->tc_lock);
4365 	} else {
4366 		spin_lock(&tcon->tc_lock);
4367 		if (tcon->status == TID_IN_TCON)
4368 			tcon->status = TID_GOOD;
4369 		tcon->need_reconnect = false;
4370 		spin_unlock(&tcon->tc_lock);
4371 	}
4372 
4373 	return rc;
4374 }
4375 #endif
4376