summaryrefslogtreecommitdiffstats
path: root/fs/cifs/misc.c
blob: 1e1626a2cfc393afb5ea6470261e6bd9703a2e40 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
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
/*
 *   fs/cifs/misc.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/mempool.h>
#include <linux/vmalloc.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smberr.h"
#include "nterr.h"
#include "cifs_unicode.h"
#include "smb2pdu.h"

extern mempool_t *cifs_sm_req_poolp;
extern mempool_t *cifs_req_poolp;

/* The xid serves as a useful identifier for each incoming vfs request,
   in a similar way to the mid which is useful to track each sent smb,
   and CurrentXid can also provide a running counter (although it
   will eventually wrap past zero) of the total vfs operations handled
   since the cifs fs was mounted */

unsigned int
_get_xid(void)
{
	unsigned int xid;

	spin_lock(&GlobalMid_Lock);
	GlobalTotalActiveXid++;

	/* keep high water mark for number of simultaneous ops in filesystem */
	if (GlobalTotalActiveXid > GlobalMaxActiveXid)
		GlobalMaxActiveXid = GlobalTotalActiveXid;
	if (GlobalTotalActiveXid > 65000)
		cifs_dbg(FYI, "warning: more than 65000 requests active\n");
	xid = GlobalCurrentXid++;
	spin_unlock(&GlobalMid_Lock);
	return xid;
}

void
_free_xid(unsigned int xid)
{
	spin_lock(&GlobalMid_Lock);
	/* if (GlobalTotalActiveXid == 0)
		BUG(); */
	GlobalTotalActiveXid--;
	spin_unlock(&GlobalMid_Lock);
}

struct cifs_ses *
sesInfoAlloc(void)
{
	struct cifs_ses *ret_buf;

	ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
	if (ret_buf) {
		atomic_inc(&sesInfoAllocCount);
		ret_buf->status = CifsNew;
		++ret_buf->ses_count;
		INIT_LIST_HEAD(&ret_buf->smb_ses_list);
		INIT_LIST_HEAD(&ret_buf->tcon_list);
		mutex_init(&ret_buf->session_mutex);
		spin_lock_init(&ret_buf->iface_lock);
	}
	return ret_buf;
}

void
sesInfoFree(struct cifs_ses *buf_to_free)
{
	if (buf_to_free == NULL) {
		cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
		return;
	}

	atomic_dec(&sesInfoAllocCount);
	kfree(buf_to_free->serverOS);
	kfree(buf_to_free->serverDomain);
	kfree(buf_to_free->serverNOS);
	kzfree(buf_to_free->password);
	kfree(buf_to_free->user_name);
	kfree(buf_to_free->domainName);
	kzfree(buf_to_free->auth_key.response);
	kfree(buf_to_free->iface_list);
	kzfree(buf_to_free);
}

struct cifs_tcon *
tconInfoAlloc(void)
{
	struct cifs_tcon *ret_buf;

	ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
	if (!ret_buf)
		return NULL;
	ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
	if (!ret_buf->crfid.fid) {
		kfree(ret_buf);
		return NULL;
	}

	atomic_inc(&tconInfoAllocCount);
	ret_buf->tidStatus = CifsNew;
	++ret_buf->tc_count;
	INIT_LIST_HEAD(&ret_buf->openFileList);
	INIT_LIST_HEAD(&ret_buf->tcon_list);
	spin_lock_init(&ret_buf->open_file_lock);
	mutex_init(&ret_buf->crfid.fid_mutex);
	spin_lock_init(&ret_buf->stat_lock);
	atomic_set(&ret_buf->num_local_opens, 0);
	atomic_set(&ret_buf->num_remote_opens, 0);

	return ret_buf;
}

void
tconInfoFree(struct cifs_tcon *buf_to_free)
{
	if (buf_to_free == NULL) {
		cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
		return;
	}
	atomic_dec(&tconInfoAllocCount);
	kfree(buf_to_free->nativeFileSystem);
	kzfree(buf_to_free->password);
	kfree(buf_to_free->crfid.fid);
#ifdef CONFIG_CIFS_DFS_UPCALL
	kfree(buf_to_free->dfs_path);
#endif
	kfree(buf_to_free);
}

struct smb_hdr *
cifs_buf_get(void)
{
	struct smb_hdr *ret_buf = NULL;
	/*
	 * SMB2 header is bigger than CIFS one - no problems to clean some
	 * more bytes for CIFS.
	 */
	size_t buf_size = sizeof(struct smb2_sync_hdr);

	/*
	 * We could use negotiated size instead of max_msgsize -
	 * but it may be more efficient to always alloc same size
	 * albeit slightly larger than necessary and maxbuffersize
	 * defaults to this and can not be bigger.
	 */
	ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);

	/* clear the first few header bytes */
	/* for most paths, more is cleared in header_assemble */
	memset(ret_buf, 0, buf_size + 3);
	atomic_inc(&bufAllocCount);
#ifdef CONFIG_CIFS_STATS2
	atomic_inc(&totBufAllocCount);
#endif /* CONFIG_CIFS_STATS2 */

	return ret_buf;
}

void
cifs_buf_release(void *buf_to_free)
{
	if (buf_to_free == NULL) {
		/* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
		return;
	}
	mempool_free(buf_to_free, cifs_req_poolp);

	atomic_dec(&bufAllocCount);
	return;
}

struct smb_hdr *
cifs_small_buf_get(void)
{
	struct smb_hdr *ret_buf = NULL;

/* We could use negotiated size instead of max_msgsize -
   but it may be more efficient to always alloc same size
   albeit slightly larger than necessary and maxbuffersize
   defaults to this and can not be bigger */
	ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
	/* No need to clear memory here, cleared in header assemble */
	/*	memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
	atomic_inc(&smBufAllocCount);
#ifdef CONFIG_CIFS_STATS2
	atomic_inc(&totSmBufAllocCount);
#endif /* CONFIG_CIFS_STATS2 */

	return ret_buf;
}

void
cifs_small_buf_release(void *buf_to_free)
{

	if (buf_to_free == NULL) {
		cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
		return;
	}
	mempool_free(buf_to_free, cifs_sm_req_poolp);

	atomic_dec(&smBufAllocCount);
	return;
}

void
free_rsp_buf(int resp_buftype, void *rsp)
{
	if (resp_buftype == CIFS_SMALL_BUFFER)
		cifs_small_buf_release(rsp);
	else if (resp_buftype == CIFS_LARGE_BUFFER)
		cifs_buf_release(rsp);
}

/* NB: MID can not be set if treeCon not passed in, in that
   case it is responsbility of caller to set the mid */
void
header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
		const struct cifs_tcon *treeCon, int word_count
		/* length of fixed section (word count) in two byte units  */)
{
	char *temp = (char *) buffer;

	memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */

	buffer->smb_buf_length = cpu_to_be32(
	    (2 * word_count) + sizeof(struct smb_hdr) -
	    4 /*  RFC 1001 length field does not count */  +
	    2 /* for bcc field itself */) ;

	buffer->Protocol[0] = 0xFF;
	buffer->Protocol[1] = 'S';
	buffer->Protocol[2] = 'M';
	buffer->Protocol[3] = 'B';
	buffer->Command = smb_command;
	buffer->Flags = 0x00;	/* case sensitive */
	buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
	buffer->Pid = cpu_to_le16((__u16)current->tgid);
	buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
	if (treeCon) {
		buffer->Tid = treeCon->tid;
		if (treeCon->ses) {
			if (treeCon->ses->capabilities & CAP_UNICODE)
				buffer->Flags2 |= SMBFLG2_UNICODE;
			if (treeCon->ses->capabilities & CAP_STATUS32)
				buffer->Flags2 |= SMBFLG2_ERR_STATUS;

			/* Uid is not converted */
			buffer->Uid = treeCon->ses->Suid;
			buffer->Mid = get_next_mid(treeCon->ses->server);
		}
		if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
			buffer->Flags2 |= SMBFLG2_DFS;
		if (treeCon->nocase)
			buffer->Flags  |= SMBFLG_CASELESS;
		if ((treeCon->ses) && (treeCon->ses->server))
			if (treeCon->ses->server->sign)
				buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
	}

/*  endian conversion of flags is now done just before sending */
	buffer->WordCount = (char) word_count;
	return;
}

static int
check_smb_hdr(struct smb_hdr *smb)
{
	/* does it have the right SMB "signature" ? */
	if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
		cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
			 *(unsigned int *)smb->Protocol);
		return 1;
	}

	/* if it's a response then accept */
	if (smb->Flags & SMBFLG_RESPONSE)
		return 0;

	/* only one valid case where server sends us request */
	if (smb->Command == SMB_COM_LOCKING_ANDX)
		return 0;

	cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
		 get_mid(smb));
	return 1;
}

int
checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
{
	struct smb_hdr *smb = (struct smb_hdr *)buf;
	__u32 rfclen = be32_to_cpu(smb->smb_buf_length);
	__u32 clc_len;  /* calculated length */
	cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
		 total_read, rfclen);

	/* is this frame too small to even get to a BCC? */
	if (total_read < 2 + sizeof(struct smb_hdr)) {
		if ((total_read >= sizeof(struct smb_hdr) - 1)
			    && (smb->Status.CifsError != 0)) {
			/* it's an error return */
			smb->WordCount = 0;
			/* some error cases do not return wct and bcc */
			return 0;
		} else if ((total_read == sizeof(struct smb_hdr) + 1) &&
				(smb->WordCount == 0)) {
			char *tmp = (char *)smb;
			/* Need to work around a bug in two servers here */
			/* First, check if the part of bcc they sent was zero */
			if (tmp[sizeof(struct smb_hdr)] == 0) {
				/* some servers return only half of bcc
				 * on simple responses (wct, bcc both zero)
				 * in particular have seen this on
				 * ulogoffX and FindClose. This leaves
				 * one byte of bcc potentially unitialized
				 */
				/* zero rest of bcc */
				tmp[sizeof(struct smb_hdr)+1] = 0;
				return 0;
			}
			cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
		} else {
			cifs_dbg(VFS, "Length less than smb header size\n");
		}
		return -EIO;
	}

	/* otherwise, there is enough to get to the BCC */
	if (check_smb_hdr(smb))
		return -EIO;
	clc_len = smbCalcSize(smb, server);

	if (4 + rfclen != total_read) {
		cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
			 rfclen);
		return -EIO;
	}

	if (4 + rfclen != clc_len) {
		__u16 mid = get_mid(smb);
		/* check if bcc wrapped around for large read responses */
		if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
			/* check if lengths match mod 64K */
			if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
				return 0; /* bcc wrapped */
		}
		cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
			 clc_len, 4 + rfclen, mid);

		if (4 + rfclen < clc_len) {
			cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
				 rfclen, mid);
			return -EIO;
		} else if (rfclen > clc_len + 512) {
			/*
			 * Some servers (Windows XP in particular) send more
			 * data than the lengths in the SMB packet would
			 * indicate on certain calls (byte range locks and
			 * trans2 find first calls in particular). While the
			 * client can handle such a frame by ignoring the
			 * trailing data, we choose limit the amount of extra
			 * data to 512 bytes.
			 */
			cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
				 rfclen, mid);
			return -EIO;
		}
	}
	return 0;
}

bool
is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
{
	struct smb_hdr *buf = (struct smb_hdr *)buffer;
	struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
	struct list_head *tmp, *tmp1, *tmp2;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct cifsInodeInfo *pCifsInode;
	struct cifsFileInfo *netfile;

	cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
	if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
	   (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
		struct smb_com_transaction_change_notify_rsp *pSMBr =
			(struct smb_com_transaction_change_notify_rsp *)buf;
		struct file_notify_information *pnotify;
		__u32 data_offset = 0;
		size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);

		if (get_bcc(buf) > sizeof(struct file_notify_information)) {
			data_offset = le32_to_cpu(pSMBr->DataOffset);

			if (data_offset >
			    len - sizeof(struct file_notify_information)) {
				cifs_dbg(FYI, "invalid data_offset %u\n",
					 data_offset);
				return true;
			}
			pnotify = (struct file_notify_information *)
				((char *)&pSMBr->hdr.Protocol + data_offset);
			cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
				 pnotify->FileName, pnotify->Action);
			/*   cifs_dump_mem("Rcvd notify Data: ",buf,
				sizeof(struct smb_hdr)+60); */
			return true;
		}
		if (pSMBr->hdr.Status.CifsError) {
			cifs_dbg(FYI, "notify err 0x%x\n",
				 pSMBr->hdr.Status.CifsError);
			return true;
		}
		return false;
	}
	if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
		return false;
	if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
		/* no sense logging error on invalid handle on oplock
		   break - harmless race between close request and oplock
		   break response is expected from time to time writing out
		   large dirty files cached on the client */
		if ((NT_STATUS_INVALID_HANDLE) ==
		   le32_to_cpu(pSMB->hdr.Status.CifsError)) {
			cifs_dbg(FYI, "invalid handle on oplock break\n");
			return true;
		} else if (ERRbadfid ==
		   le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
			return true;
		} else {
			return false; /* on valid oplock brk we get "request" */
		}
	}
	if (pSMB->hdr.WordCount != 8)
		return false;

	cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
		 pSMB->LockType, pSMB->OplockLevel);
	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
		return false;

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &srv->smb_ses_list) {
		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
		list_for_each(tmp1, &ses->tcon_list) {
			tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
			if (tcon->tid != buf->Tid)
				continue;

			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
			spin_lock(&tcon->open_file_lock);
			list_for_each(tmp2, &tcon->openFileList) {
				netfile = list_entry(tmp2, struct cifsFileInfo,
						     tlist);
				if (pSMB->Fid != netfile->fid.netfid)
					continue;

				cifs_dbg(FYI, "file id match, oplock break\n");
				pCifsInode = CIFS_I(d_inode(netfile->dentry));

				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
					&pCifsInode->flags);

				/*
				 * Set flag if the server downgrades the oplock
				 * to L2 else clear.
				 */
				if (pSMB->OplockLevel)
					set_bit(
					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
					   &pCifsInode->flags);
				else
					clear_bit(
					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
					   &pCifsInode->flags);

				cifs_queue_oplock_break(netfile);
				netfile->oplock_break_cancelled = false;

				spin_unlock(&tcon->open_file_lock);
				spin_unlock(&cifs_tcp_ses_lock);
				return true;
			}
			spin_unlock(&tcon->open_file_lock);
			spin_unlock(&cifs_tcp_ses_lock);
			cifs_dbg(FYI, "No matching file for oplock break\n");
			return true;
		}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
	return true;
}

void
dump_smb(void *buf, int smb_buf_length)
{
	if (traceSMB == 0)
		return;

	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
		       smb_buf_length, true);
}

void
cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
{
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
		struct cifs_tcon *tcon = NULL;

		if (cifs_sb->master_tlink)
			tcon = cifs_sb_master_tcon(cifs_sb);

		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
		cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s.\n",
			 tcon ? tcon->treeName : "new server");
		cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS).\n");
		cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");

	}
}

void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
{
	oplock &= 0xF;

	if (oplock == OPLOCK_EXCLUSIVE) {
		cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
		cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
			 &cinode->vfs_inode);
	} else if (oplock == OPLOCK_READ) {
		cinode->oplock = CIFS_CACHE_READ_FLG;
		cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
			 &cinode->vfs_inode);
	} else
		cinode->oplock = 0;
}

/*
 * We wait for oplock breaks to be processed before we attempt to perform
 * writes.
 */
int cifs_get_writer(struct cifsInodeInfo *cinode)
{
	int rc;

start:
	rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
			 TASK_KILLABLE);
	if (rc)
		return rc;

	spin_lock(&cinode->writers_lock);
	if (!cinode->writers)
		set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
	cinode->writers++;
	/* Check to see if we have started servicing an oplock break */
	if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
		cinode->writers--;
		if (cinode->writers == 0) {
			clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
			wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
		}
		spin_unlock(&cinode->writers_lock);
		goto start;
	}
	spin_unlock(&cinode->writers_lock);
	return 0;
}

void cifs_put_writer(struct cifsInodeInfo *cinode)
{
	spin_lock(&cinode->writers_lock);
	cinode->writers--;
	if (cinode->writers == 0) {
		clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
		wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
	}
	spin_unlock(&cinode->writers_lock);
}

/**
 * cifs_queue_oplock_break - queue the oplock break handler for cfile
 *
 * This function is called from the demultiplex thread when it
 * receives an oplock break for @cfile.
 *
 * Assumes the tcon->open_file_lock is held.
 * Assumes cfile->file_info_lock is NOT held.
 */
void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
{
	/*
	 * Bump the handle refcount now while we hold the
	 * open_file_lock to enforce the validity of it for the oplock
	 * break handler. The matching put is done at the end of the
	 * handler.
	 */
	cifsFileInfo_get(cfile);

	queue_work(cifsoplockd_wq, &cfile->oplock_break);
}

void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
{
	clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
	wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
}

bool
backup_cred(struct cifs_sb_info *cifs_sb)
{
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
		if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
			return true;
	}
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
		if (in_group_p(cifs_sb->mnt_backupgid))
			return true;
	}

	return false;
}

void
cifs_del_pending_open(struct cifs_pending_open *open)
{
	spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
	list_del(&open->olist);
	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
}

void
cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
			     struct cifs_pending_open *open)
{
	memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
	open->oplock = CIFS_OPLOCK_NO_CHANGE;
	open->tlink = tlink;
	fid->pending_open = open;
	list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
}

void
cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
		      struct cifs_pending_open *open)
{
	spin_lock(&tlink_tcon(tlink)->open_file_lock);
	cifs_add_pending_open_locked(fid, tlink, open);
	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
}

/* parses DFS refferal V3 structure
 * caller is responsible for freeing target_nodes
 * returns:
 * - on success - 0
 * - on failure - errno
 */
int
parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
		    unsigned int *num_of_nodes,
		    struct dfs_info3_param **target_nodes,
		    const struct nls_table *nls_codepage, int remap,
		    const char *searchName, bool is_unicode)
{
	int i, rc = 0;
	char *data_end;
	struct dfs_referral_level_3 *ref;

	*num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);

	if (*num_of_nodes < 1) {
		cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
			 *num_of_nodes);
		rc = -EINVAL;
		goto parse_DFS_referrals_exit;
	}

	ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
	if (ref->VersionNumber != cpu_to_le16(3)) {
		cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
			 le16_to_cpu(ref->VersionNumber));
		rc = -EINVAL;
		goto parse_DFS_referrals_exit;
	}

	/* get the upper boundary of the resp buffer */
	data_end = (char *)rsp + rsp_size;

	cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
		 *num_of_nodes, le32_to_cpu(rsp->DFSFlags));

	*target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
				GFP_KERNEL);
	if (*target_nodes == NULL) {
		rc = -ENOMEM;
		goto parse_DFS_referrals_exit;
	}

	/* collect necessary data from referrals */
	for (i = 0; i < *num_of_nodes; i++) {
		char *temp;
		int max_len;
		struct dfs_info3_param *node = (*target_nodes)+i;

		node->flags = le32_to_cpu(rsp->DFSFlags);
		if (is_unicode) {
			__le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
						GFP_KERNEL);
			if (tmp == NULL) {
				rc = -ENOMEM;
				goto parse_DFS_referrals_exit;
			}
			cifsConvertToUTF16((__le16 *) tmp, searchName,
					   PATH_MAX, nls_codepage, remap);
			node->path_consumed = cifs_utf16_bytes(tmp,
					le16_to_cpu(rsp->PathConsumed),
					nls_codepage);
			kfree(tmp);
		} else
			node->path_consumed = le16_to_cpu(rsp->PathConsumed);

		node->server_type = le16_to_cpu(ref->ServerType);
		node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);

		/* copy DfsPath */
		temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
		max_len = data_end - temp;
		node->path_name = cifs_strndup_from_utf16(temp, max_len,
						is_unicode, nls_codepage);
		if (!node->path_name) {
			rc = -ENOMEM;
			goto parse_DFS_referrals_exit;
		}

		/* copy link target UNC */
		temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
		max_len = data_end - temp;
		node->node_name = cifs_strndup_from_utf16(temp, max_len,
						is_unicode, nls_codepage);
		if (!node->node_name) {
			rc = -ENOMEM;
			goto parse_DFS_referrals_exit;
		}

		node->ttl = le32_to_cpu(ref->TimeToLive);

		ref++;
	}

parse_DFS_referrals_exit:
	if (rc) {
		free_dfs_info_array(*target_nodes, *num_of_nodes);
		*target_nodes = NULL;
		*num_of_nodes = 0;
	}
	return rc;
}

struct cifs_aio_ctx *
cifs_aio_ctx_alloc(void)
{
	struct cifs_aio_ctx *ctx;

	ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
	if (!ctx)
		return NULL;

	INIT_LIST_HEAD(&ctx->list);
	mutex_init(&ctx->aio_mutex);
	init_completion(&ctx->done);
	kref_init(&ctx->refcount);
	return ctx;
}

void
cifs_aio_ctx_release(struct kref *refcount)
{
	struct cifs_aio_ctx *ctx = container_of(refcount,
					struct cifs_aio_ctx, refcount);

	cifsFileInfo_put(ctx->cfile);
	kvfree(ctx->bv);
	kfree(ctx);
}

#define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)

int
setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
{
	ssize_t rc;
	unsigned int cur_npages;
	unsigned int npages = 0;
	unsigned int i;
	size_t len;
	size_t count = iov_iter_count(iter);
	unsigned int saved_len;
	size_t start;
	unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
	struct page **pages = NULL;
	struct bio_vec *bv = NULL;

	if (iov_iter_is_kvec(iter)) {
		memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
		ctx->len = count;
		iov_iter_advance(iter, count);
		return 0;
	}

	if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
		bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
				   GFP_KERNEL);

	if (!bv) {
		bv = vmalloc(array_size(max_pages, sizeof(struct bio_vec)));
		if (!bv)
			return -ENOMEM;
	}

	if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
		pages = kmalloc_array(max_pages, sizeof(struct page *),
				      GFP_KERNEL);

	if (!pages) {
		pages = vmalloc(array_size(max_pages, sizeof(struct page *)));
		if (!pages) {
			kvfree(bv);
			return -ENOMEM;
		}
	}

	saved_len = count;

	while (count && npages < max_pages) {
		rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
		if (rc < 0) {
			cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
			break;
		}

		if (rc > count) {
			cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
				 count);
			break;
		}

		iov_iter_advance(iter, rc);
		count -= rc;
		rc += start;
		cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);

		if (npages + cur_npages > max_pages) {
			cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
				 npages + cur_npages, max_pages);
			break;
		}

		for (i = 0; i < cur_npages; i++) {
			len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
			bv[npages + i].bv_page = pages[i];
			bv[npages + i].bv_offset = start;
			bv[npages + i].bv_len = len - start;
			rc -= len;
			start = 0;
		}

		npages += cur_npages;
	}

	kvfree(pages);
	ctx->bv = bv;
	ctx->len = saved_len - count;
	ctx->npages = npages;
	iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
	return 0;
}

/**
 * cifs_alloc_hash - allocate hash and hash context together
 *
 * The caller has to make sure @sdesc is initialized to either NULL or
 * a valid context. Both can be freed via cifs_free_hash().
 */
int
cifs_alloc_hash(const char *name,
		struct crypto_shash **shash, struct sdesc **sdesc)
{
	int rc = 0;
	size_t size;

	if (*sdesc != NULL)
		return 0;

	*shash = crypto_alloc_shash(name, 0, 0);
	if (IS_ERR(*shash)) {
		cifs_dbg(VFS, "could not allocate crypto %s\n", name);
		rc = PTR_ERR(*shash);
		*shash = NULL;
		*sdesc = NULL;
		return rc;
	}

	size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
	*sdesc = kmalloc(size, GFP_KERNEL);
	if (*sdesc == NULL) {
		cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
		crypto_free_shash(*shash);
		*shash = NULL;
		return -ENOMEM;
	}

	(*sdesc)->shash.tfm = *shash;
	(*sdesc)->shash.flags = 0x0;
	return 0;
}

/**
 * cifs_free_hash - free hash and hash context together
 *
 * Freeing a NULL hash or context is safe.
 */
void
cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
{
	kfree(*sdesc);
	*sdesc = NULL;
	if (*shash)
		crypto_free_shash(*shash);
	*shash = NULL;
}

/**
 * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
 * Input: rqst - a smb_rqst, page - a page index for rqst
 * Output: *len - the length for this page, *offset - the offset for this page
 */
void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
				unsigned int *len, unsigned int *offset)
{
	*len = rqst->rq_pagesz;
	*offset = (page == 0) ? rqst->rq_offset : 0;

	if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
		*len = rqst->rq_tailsz;
	else if (page == 0)
		*len = rqst->rq_pagesz - rqst->rq_offset;
}

void extract_unc_hostname(const char *unc, const char **h, size_t *len)
{
	const char *end;

	/* skip initial slashes */
	while (*unc && (*unc == '\\' || *unc == '/'))
		unc++;

	end = unc;

	while (*end && !(*end == '\\' || *end == '/'))
		end++;

	*h = unc;
	*len = end - unc;
}