forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathconnect.c
4593 lines (3982 loc) · 123 KB
/
connect.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// SPDX-License-Identifier: LGPL-2.1
/*
*
* Copyright (C) International Business Machines Corp., 2002,2011
* Author(s): Steve French ([email protected])
*
*/
#include <linux/fs.h>
#include <linux/net.h>
#include <linux/string.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/ctype.h>
#include <linux/utsname.h>
#include <linux/mempool.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/pagevec.h>
#include <linux/freezer.h>
#include <linux/namei.h>
#include <linux/uuid.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <linux/inet.h>
#include <linux/module.h>
#include <keys/user-type.h>
#include <net/ipv6.h>
#include <linux/parser.h>
#include <linux/bvec.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "ntlmssp.h"
#include "nterr.h"
#include "rfc1002pdu.h"
#include "fscache.h"
#include "smb2proto.h"
#include "smbdirect.h"
#include "dns_resolve.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif
#include "fs_context.h"
#include "cifs_swn.h"
extern mempool_t *cifs_req_poolp;
extern bool disable_legacy_dialects;
/* FIXME: should these be tunable? */
#define TLINK_ERROR_EXPIRE (1 * HZ)
#define TLINK_IDLE_EXPIRE (600 * HZ)
/* Drop the connection to not overload the server */
#define NUM_STATUS_IO_TIMEOUT 5
struct mount_ctx {
struct cifs_sb_info *cifs_sb;
struct smb3_fs_context *fs_ctx;
unsigned int xid;
struct TCP_Server_Info *server;
struct cifs_ses *ses;
struct cifs_tcon *tcon;
#ifdef CONFIG_CIFS_DFS_UPCALL
struct cifs_ses *root_ses;
uuid_t mount_id;
char *origin_fullpath, *leaf_fullpath;
#endif
};
static int ip_connect(struct TCP_Server_Info *server);
static int generic_ip_connect(struct TCP_Server_Info *server);
static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
static void cifs_prune_tlinks(struct work_struct *work);
/*
* Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
* get their ip addresses changed at some point.
*
* This should be called with server->srv_mutex held.
*/
static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
{
int rc;
int len;
char *unc, *ipaddr = NULL;
time64_t expiry, now;
unsigned long ttl = SMB_DNS_RESOLVE_INTERVAL_DEFAULT;
if (!server->hostname)
return -EINVAL;
len = strlen(server->hostname) + 3;
unc = kmalloc(len, GFP_KERNEL);
if (!unc) {
cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
return -ENOMEM;
}
scnprintf(unc, len, "\\\\%s", server->hostname);
rc = dns_resolve_server_name_to_ip(unc, &ipaddr, &expiry);
kfree(unc);
if (rc < 0) {
cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
__func__, server->hostname, rc);
goto requeue_resolve;
}
spin_lock(&cifs_tcp_ses_lock);
rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
strlen(ipaddr));
spin_unlock(&cifs_tcp_ses_lock);
kfree(ipaddr);
/* rc == 1 means success here */
if (rc) {
now = ktime_get_real_seconds();
if (expiry && expiry > now)
/*
* To make sure we don't use the cached entry, retry 1s
* after expiry.
*/
ttl = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 1;
}
rc = !rc ? -1 : 0;
requeue_resolve:
cifs_dbg(FYI, "%s: next dns resolution scheduled for %lu seconds in the future\n",
__func__, ttl);
mod_delayed_work(cifsiod_wq, &server->resolve, (ttl * HZ));
return rc;
}
static void cifs_resolve_server(struct work_struct *work)
{
int rc;
struct TCP_Server_Info *server = container_of(work,
struct TCP_Server_Info, resolve.work);
mutex_lock(&server->srv_mutex);
/*
* Resolve the hostname again to make sure that IP address is up-to-date.
*/
rc = reconn_set_ipaddr_from_hostname(server);
if (rc) {
cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
__func__, rc);
}
mutex_unlock(&server->srv_mutex);
}
/*
* Update the tcpStatus for the server.
* This is used to signal the cifsd thread to call cifs_reconnect
* ONLY cifsd thread should call cifs_reconnect. For any other
* thread, use this function
*
* @server: the tcp ses for which reconnect is needed
* @all_channels: if this needs to be done for all channels
*/
void
cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
bool all_channels)
{
struct TCP_Server_Info *pserver;
struct cifs_ses *ses;
int i;
/* If server is a channel, select the primary channel */
pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
spin_lock(&cifs_tcp_ses_lock);
if (!all_channels) {
pserver->tcpStatus = CifsNeedReconnect;
spin_unlock(&cifs_tcp_ses_lock);
return;
}
list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
spin_lock(&ses->chan_lock);
for (i = 0; i < ses->chan_count; i++)
ses->chans[i].server->tcpStatus = CifsNeedReconnect;
spin_unlock(&ses->chan_lock);
}
spin_unlock(&cifs_tcp_ses_lock);
}
/*
* Mark all sessions and tcons for reconnect.
* IMPORTANT: make sure that this gets called only from
* cifsd thread. For any other thread, use
* cifs_signal_cifsd_for_reconnect
*
* @server: the tcp ses for which reconnect is needed
* @server needs to be previously set to CifsNeedReconnect.
* @mark_smb_session: whether even sessions need to be marked
*/
void
cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
bool mark_smb_session)
{
struct TCP_Server_Info *pserver;
struct cifs_ses *ses;
struct cifs_tcon *tcon;
/*
* before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they
* are not used until reconnected.
*/
cifs_dbg(FYI, "%s: marking necessary sessions and tcons for reconnect\n", __func__);
/* If server is a channel, select the primary channel */
pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
spin_lock(&cifs_tcp_ses_lock);
list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
spin_lock(&ses->chan_lock);
if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server))
goto next_session;
if (mark_smb_session)
CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses);
else
cifs_chan_set_need_reconnect(ses, server);
/* If all channels need reconnect, then tcon needs reconnect */
if (!mark_smb_session && !CIFS_ALL_CHANS_NEED_RECONNECT(ses))
goto next_session;
ses->status = CifsNeedReconnect;
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
tcon->need_reconnect = true;
tcon->status = TID_NEED_RECON;
}
if (ses->tcon_ipc)
ses->tcon_ipc->need_reconnect = true;
next_session:
spin_unlock(&ses->chan_lock);
}
spin_unlock(&cifs_tcp_ses_lock);
}
static void
cifs_abort_connection(struct TCP_Server_Info *server)
{
struct mid_q_entry *mid, *nmid;
struct list_head retry_list;
server->maxBuf = 0;
server->max_read = 0;
/* do not want to be sending data on a socket we are freeing */
cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
mutex_lock(&server->srv_mutex);
if (server->ssocket) {
cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
server->ssocket->flags);
kernel_sock_shutdown(server->ssocket, SHUT_WR);
cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n", server->ssocket->state,
server->ssocket->flags);
sock_release(server->ssocket);
server->ssocket = NULL;
}
server->sequence_number = 0;
server->session_estab = false;
kfree(server->session_key.response);
server->session_key.response = NULL;
server->session_key.len = 0;
server->lstrp = jiffies;
/* mark submitted MIDs for retry and issue callback */
INIT_LIST_HEAD(&retry_list);
cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
spin_lock(&GlobalMid_Lock);
list_for_each_entry_safe(mid, nmid, &server->pending_mid_q, qhead) {
kref_get(&mid->refcount);
if (mid->mid_state == MID_REQUEST_SUBMITTED)
mid->mid_state = MID_RETRY_NEEDED;
list_move(&mid->qhead, &retry_list);
mid->mid_flags |= MID_DELETED;
}
spin_unlock(&GlobalMid_Lock);
mutex_unlock(&server->srv_mutex);
cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
list_del_init(&mid->qhead);
mid->callback(mid);
cifs_mid_q_entry_release(mid);
}
if (cifs_rdma_enabled(server)) {
mutex_lock(&server->srv_mutex);
smbd_destroy(server);
mutex_unlock(&server->srv_mutex);
}
}
static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
{
spin_lock(&cifs_tcp_ses_lock);
server->nr_targets = num_targets;
if (server->tcpStatus == CifsExiting) {
/* the demux thread will exit normally next time through the loop */
spin_unlock(&cifs_tcp_ses_lock);
wake_up(&server->response_q);
return false;
}
cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
trace_smb3_reconnect(server->CurrentMid, server->conn_id,
server->hostname);
server->tcpStatus = CifsNeedReconnect;
spin_unlock(&cifs_tcp_ses_lock);
return true;
}
/*
* cifs tcp session reconnection
*
* mark tcp session as reconnecting so temporarily locked
* mark all smb sessions as reconnecting for tcp session
* reconnect tcp session
* wake up waiters on reconnection? - (not needed currently)
*
* if mark_smb_session is passed as true, unconditionally mark
* the smb session (and tcon) for reconnect as well. This value
* doesn't really matter for non-multichannel scenario.
*
*/
static int __cifs_reconnect(struct TCP_Server_Info *server,
bool mark_smb_session)
{
int rc = 0;
if (!cifs_tcp_ses_needs_reconnect(server, 1))
return 0;
cifs_mark_tcp_ses_conns_for_reconnect(server, mark_smb_session);
cifs_abort_connection(server);
do {
try_to_freeze();
mutex_lock(&server->srv_mutex);
if (!cifs_swn_set_server_dstaddr(server)) {
/* resolve the hostname again to make sure that IP address is up-to-date */
rc = reconn_set_ipaddr_from_hostname(server);
cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
}
if (cifs_rdma_enabled(server))
rc = smbd_reconnect(server);
else
rc = generic_ip_connect(server);
if (rc) {
mutex_unlock(&server->srv_mutex);
cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
msleep(3000);
} else {
atomic_inc(&tcpSesReconnectCount);
set_credits(server, 1);
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus != CifsExiting)
server->tcpStatus = CifsNeedNegotiate;
spin_unlock(&cifs_tcp_ses_lock);
cifs_swn_reset_server_dstaddr(server);
mutex_unlock(&server->srv_mutex);
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
}
} while (server->tcpStatus == CifsNeedReconnect);
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsNeedNegotiate)
mod_delayed_work(cifsiod_wq, &server->echo, 0);
spin_unlock(&cifs_tcp_ses_lock);
wake_up(&server->response_q);
return rc;
}
#ifdef CONFIG_CIFS_DFS_UPCALL
static int __reconnect_target_unlocked(struct TCP_Server_Info *server, const char *target)
{
int rc;
char *hostname;
if (!cifs_swn_set_server_dstaddr(server)) {
if (server->hostname != target) {
hostname = extract_hostname(target);
if (!IS_ERR(hostname)) {
kfree(server->hostname);
server->hostname = hostname;
} else {
cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
__func__, PTR_ERR(hostname));
cifs_dbg(FYI, "%s: default to last target server: %s\n", __func__,
server->hostname);
}
}
/* resolve the hostname again to make sure that IP address is up-to-date. */
rc = reconn_set_ipaddr_from_hostname(server);
cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
}
/* Reconnect the socket */
if (cifs_rdma_enabled(server))
rc = smbd_reconnect(server);
else
rc = generic_ip_connect(server);
return rc;
}
static int reconnect_target_unlocked(struct TCP_Server_Info *server, struct dfs_cache_tgt_list *tl,
struct dfs_cache_tgt_iterator **target_hint)
{
int rc;
struct dfs_cache_tgt_iterator *tit;
*target_hint = NULL;
/* If dfs target list is empty, then reconnect to last server */
tit = dfs_cache_get_tgt_iterator(tl);
if (!tit)
return __reconnect_target_unlocked(server, server->hostname);
/* Otherwise, try every dfs target in @tl */
for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
rc = __reconnect_target_unlocked(server, dfs_cache_get_tgt_name(tit));
if (!rc) {
*target_hint = tit;
break;
}
}
return rc;
}
static int reconnect_dfs_server(struct TCP_Server_Info *server)
{
int rc = 0;
const char *refpath = server->current_fullpath + 1;
struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
struct dfs_cache_tgt_iterator *target_hint = NULL;
int num_targets = 0;
/*
* Determine the number of dfs targets the referral path in @cifs_sb resolves to.
*
* smb2_reconnect() needs to know how long it should wait based upon the number of dfs
* targets (server->nr_targets). It's also possible that the cached referral was cleared
* through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
* refreshing the referral, so, in this case, default it to 1.
*/
if (!dfs_cache_noreq_find(refpath, NULL, &tl))
num_targets = dfs_cache_get_nr_tgts(&tl);
if (!num_targets)
num_targets = 1;
if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
return 0;
/*
* Unconditionally mark all sessions & tcons for reconnect as we might be connecting to a
* different server or share during failover. It could be improved by adding some logic to
* only do that in case it connects to a different server or share, though.
*/
cifs_mark_tcp_ses_conns_for_reconnect(server, true);
cifs_abort_connection(server);
do {
try_to_freeze();
mutex_lock(&server->srv_mutex);
rc = reconnect_target_unlocked(server, &tl, &target_hint);
if (rc) {
/* Failed to reconnect socket */
mutex_unlock(&server->srv_mutex);
cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
msleep(3000);
continue;
}
/*
* Socket was created. Update tcp session status to CifsNeedNegotiate so that a
* process waiting for reconnect will know it needs to re-establish session and tcon
* through the reconnected target server.
*/
atomic_inc(&tcpSesReconnectCount);
set_credits(server, 1);
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus != CifsExiting)
server->tcpStatus = CifsNeedNegotiate;
spin_unlock(&cifs_tcp_ses_lock);
cifs_swn_reset_server_dstaddr(server);
mutex_unlock(&server->srv_mutex);
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
} while (server->tcpStatus == CifsNeedReconnect);
if (target_hint)
dfs_cache_noreq_update_tgthint(refpath, target_hint);
dfs_cache_free_tgts(&tl);
/* Need to set up echo worker again once connection has been established */
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsNeedNegotiate)
mod_delayed_work(cifsiod_wq, &server->echo, 0);
spin_unlock(&cifs_tcp_ses_lock);
wake_up(&server->response_q);
return rc;
}
int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
{
/* If tcp session is not an dfs connection, then reconnect to last target server */
spin_lock(&cifs_tcp_ses_lock);
if (!server->is_dfs_conn) {
spin_unlock(&cifs_tcp_ses_lock);
return __cifs_reconnect(server, mark_smb_session);
}
spin_unlock(&cifs_tcp_ses_lock);
mutex_lock(&server->refpath_lock);
if (!server->origin_fullpath || !server->leaf_fullpath) {
mutex_unlock(&server->refpath_lock);
return __cifs_reconnect(server, mark_smb_session);
}
mutex_unlock(&server->refpath_lock);
return reconnect_dfs_server(server);
}
#else
int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
{
return __cifs_reconnect(server, mark_smb_session);
}
#endif
static void
cifs_echo_request(struct work_struct *work)
{
int rc;
struct TCP_Server_Info *server = container_of(work,
struct TCP_Server_Info, echo.work);
/*
* We cannot send an echo if it is disabled.
* Also, no need to ping if we got a response recently.
*/
if (server->tcpStatus == CifsNeedReconnect ||
server->tcpStatus == CifsExiting ||
server->tcpStatus == CifsNew ||
(server->ops->can_echo && !server->ops->can_echo(server)) ||
time_before(jiffies, server->lstrp + server->echo_interval - HZ))
goto requeue_echo;
rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
if (rc)
cifs_dbg(FYI, "Unable to send echo request to server: %s\n",
server->hostname);
/* Check witness registrations */
cifs_swn_check();
requeue_echo:
queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
}
static bool
allocate_buffers(struct TCP_Server_Info *server)
{
if (!server->bigbuf) {
server->bigbuf = (char *)cifs_buf_get();
if (!server->bigbuf) {
cifs_server_dbg(VFS, "No memory for large SMB response\n");
msleep(3000);
/* retry will check if exiting */
return false;
}
} else if (server->large_buf) {
/* we are reusing a dirty large buf, clear its start */
memset(server->bigbuf, 0, HEADER_SIZE(server));
}
if (!server->smallbuf) {
server->smallbuf = (char *)cifs_small_buf_get();
if (!server->smallbuf) {
cifs_server_dbg(VFS, "No memory for SMB response\n");
msleep(1000);
/* retry will check if exiting */
return false;
}
/* beginning of smb buffer is cleared in our buf_get */
} else {
/* if existing small buf clear beginning */
memset(server->smallbuf, 0, HEADER_SIZE(server));
}
return true;
}
static bool
server_unresponsive(struct TCP_Server_Info *server)
{
/*
* We need to wait 3 echo intervals to make sure we handle such
* situations right:
* 1s client sends a normal SMB request
* 2s client gets a response
* 30s echo workqueue job pops, and decides we got a response recently
* and don't need to send another
* ...
* 65s kernel_recvmsg times out, and we see that we haven't gotten
* a response in >60s.
*/
spin_lock(&cifs_tcp_ses_lock);
if ((server->tcpStatus == CifsGood ||
server->tcpStatus == CifsNeedNegotiate) &&
(!server->ops->can_echo || server->ops->can_echo(server)) &&
time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
spin_unlock(&cifs_tcp_ses_lock);
cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
(3 * server->echo_interval) / HZ);
cifs_reconnect(server, false);
return true;
}
spin_unlock(&cifs_tcp_ses_lock);
return false;
}
static inline bool
zero_credits(struct TCP_Server_Info *server)
{
int val;
spin_lock(&server->req_lock);
val = server->credits + server->echo_credits + server->oplock_credits;
if (server->in_flight == 0 && val == 0) {
spin_unlock(&server->req_lock);
return true;
}
spin_unlock(&server->req_lock);
return false;
}
static int
cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
{
int length = 0;
int total_read;
smb_msg->msg_control = NULL;
smb_msg->msg_controllen = 0;
for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
try_to_freeze();
/* reconnect if no credits and no requests in flight */
if (zero_credits(server)) {
cifs_reconnect(server, false);
return -ECONNABORTED;
}
if (server_unresponsive(server))
return -ECONNABORTED;
if (cifs_rdma_enabled(server) && server->smbd_conn)
length = smbd_recv(server->smbd_conn, smb_msg);
else
length = sock_recvmsg(server->ssocket, smb_msg, 0);
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&cifs_tcp_ses_lock);
return -ESHUTDOWN;
}
if (server->tcpStatus == CifsNeedReconnect) {
spin_unlock(&cifs_tcp_ses_lock);
cifs_reconnect(server, false);
return -ECONNABORTED;
}
spin_unlock(&cifs_tcp_ses_lock);
if (length == -ERESTARTSYS ||
length == -EAGAIN ||
length == -EINTR) {
/*
* Minimum sleep to prevent looping, allowing socket
* to clear and app threads to set tcpStatus
* CifsNeedReconnect if server hung.
*/
usleep_range(1000, 2000);
length = 0;
continue;
}
if (length <= 0) {
cifs_dbg(FYI, "Received no data or error: %d\n", length);
cifs_reconnect(server, false);
return -ECONNABORTED;
}
}
return total_read;
}
int
cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
unsigned int to_read)
{
struct msghdr smb_msg;
struct kvec iov = {.iov_base = buf, .iov_len = to_read};
iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
return cifs_readv_from_socket(server, &smb_msg);
}
ssize_t
cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
{
struct msghdr smb_msg;
/*
* iov_iter_discard already sets smb_msg.type and count and iov_offset
* and cifs_readv_from_socket sets msg_control and msg_controllen
* so little to initialize in struct msghdr
*/
smb_msg.msg_name = NULL;
smb_msg.msg_namelen = 0;
iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
return cifs_readv_from_socket(server, &smb_msg);
}
int
cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
unsigned int page_offset, unsigned int to_read)
{
struct msghdr smb_msg;
struct bio_vec bv = {
.bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
return cifs_readv_from_socket(server, &smb_msg);
}
static bool
is_smb_response(struct TCP_Server_Info *server, unsigned char type)
{
/*
* The first byte big endian of the length field,
* is actually not part of the length but the type
* with the most common, zero, as regular data.
*/
switch (type) {
case RFC1002_SESSION_MESSAGE:
/* Regular SMB response */
return true;
case RFC1002_SESSION_KEEP_ALIVE:
cifs_dbg(FYI, "RFC 1002 session keep alive\n");
break;
case RFC1002_POSITIVE_SESSION_RESPONSE:
cifs_dbg(FYI, "RFC 1002 positive session response\n");
break;
case RFC1002_NEGATIVE_SESSION_RESPONSE:
/*
* We get this from Windows 98 instead of an error on
* SMB negprot response.
*/
cifs_dbg(FYI, "RFC 1002 negative session response\n");
/* give server a second to clean up */
msleep(1000);
/*
* Always try 445 first on reconnect since we get NACK
* on some if we ever connected to port 139 (the NACK
* is since we do not begin with RFC1001 session
* initialize frame).
*/
cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
cifs_reconnect(server, true);
break;
default:
cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
cifs_reconnect(server, true);
}
return false;
}
void
dequeue_mid(struct mid_q_entry *mid, bool malformed)
{
#ifdef CONFIG_CIFS_STATS2
mid->when_received = jiffies;
#endif
spin_lock(&GlobalMid_Lock);
if (!malformed)
mid->mid_state = MID_RESPONSE_RECEIVED;
else
mid->mid_state = MID_RESPONSE_MALFORMED;
/*
* Trying to handle/dequeue a mid after the send_recv()
* function has finished processing it is a bug.
*/
if (mid->mid_flags & MID_DELETED) {
spin_unlock(&GlobalMid_Lock);
pr_warn_once("trying to dequeue a deleted mid\n");
} else {
list_del_init(&mid->qhead);
mid->mid_flags |= MID_DELETED;
spin_unlock(&GlobalMid_Lock);
}
}
static unsigned int
smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
{
struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
/*
* SMB1 does not use credits.
*/
if (server->vals->header_preamble_size)
return 0;
return le16_to_cpu(shdr->CreditRequest);
}
static void
handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
char *buf, int malformed)
{
if (server->ops->check_trans2 &&
server->ops->check_trans2(mid, server, buf, malformed))
return;
mid->credits_received = smb2_get_credits_from_hdr(buf, server);
mid->resp_buf = buf;
mid->large_buf = server->large_buf;
/* Was previous buf put in mpx struct for multi-rsp? */
if (!mid->multiRsp) {
/* smb buffer will be freed by user thread */
if (server->large_buf)
server->bigbuf = NULL;
else
server->smallbuf = NULL;
}
dequeue_mid(mid, malformed);
}
static void clean_demultiplex_info(struct TCP_Server_Info *server)
{
int length;
/* take it off the list, if it's not already */
spin_lock(&cifs_tcp_ses_lock);
list_del_init(&server->tcp_ses_list);
spin_unlock(&cifs_tcp_ses_lock);
cancel_delayed_work_sync(&server->echo);
cancel_delayed_work_sync(&server->resolve);
spin_lock(&cifs_tcp_ses_lock);
server->tcpStatus = CifsExiting;
spin_unlock(&cifs_tcp_ses_lock);
wake_up_all(&server->response_q);
/* check if we have blocked requests that need to free */
spin_lock(&server->req_lock);
if (server->credits <= 0)
server->credits = 1;
spin_unlock(&server->req_lock);
/*
* Although there should not be any requests blocked on this queue it
* can not hurt to be paranoid and try to wake up requests that may
* haven been blocked when more than 50 at time were on the wire to the
* same server - they now will see the session is in exit state and get
* out of SendReceive.
*/
wake_up_all(&server->request_q);
/* give those requests time to exit */
msleep(125);
if (cifs_rdma_enabled(server))
smbd_destroy(server);
if (server->ssocket) {
sock_release(server->ssocket);
server->ssocket = NULL;
}
if (!list_empty(&server->pending_mid_q)) {
struct list_head dispose_list;
struct mid_q_entry *mid_entry;
struct list_head *tmp, *tmp2;
INIT_LIST_HEAD(&dispose_list);
spin_lock(&GlobalMid_Lock);
list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
kref_get(&mid_entry->refcount);
mid_entry->mid_state = MID_SHUTDOWN;
list_move(&mid_entry->qhead, &dispose_list);
mid_entry->mid_flags |= MID_DELETED;
}
spin_unlock(&GlobalMid_Lock);
/* now walk dispose list and issue callbacks */
list_for_each_safe(tmp, tmp2, &dispose_list) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
list_del_init(&mid_entry->qhead);
mid_entry->callback(mid_entry);
cifs_mid_q_entry_release(mid_entry);
}
/* 1/8th of sec is more than enough time for them to exit */
msleep(125);
}
if (!list_empty(&server->pending_mid_q)) {
/*
* mpx threads have not exited yet give them at least the smb
* send timeout time for long ops.
*
* Due to delays on oplock break requests, we need to wait at
* least 45 seconds before giving up on a request getting a
* response and going ahead and killing cifsd.
*/
cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
msleep(46000);
/*
* If threads still have not exited they are probably never
* coming home not much else we can do but free the memory.
*/
}
#ifdef CONFIG_CIFS_DFS_UPCALL
kfree(server->origin_fullpath);
kfree(server->leaf_fullpath);
#endif
kfree(server);
length = atomic_dec_return(&tcpSesAllocCount);
if (length > 0)
mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
}
static int
standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
int length;
char *buf = server->smallbuf;
unsigned int pdu_length = server->pdu_size;
/* make sure this will fit in a large buffer */
if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
server->vals->header_preamble_size) {
cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
cifs_reconnect(server, true);
return -ECONNABORTED;
}
/* switch to large buffer if too big for a small one */
if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
server->large_buf = true;
memcpy(server->bigbuf, buf, server->total_read);
buf = server->bigbuf;
}
/* now read the rest */
length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
pdu_length - HEADER_SIZE(server) + 1
+ server->vals->header_preamble_size);
if (length < 0)
return length;
server->total_read += length;
dump_smb(buf, server->total_read);
return cifs_handle_standard(server, mid);
}