summaryrefslogtreecommitdiffstats
path: root/net/9p/client.c
blob: bde9f3d38c579eca51183cf38cb7f33effad8055 (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
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
/*
 * net/9p/clnt.c
 *
 * 9P Client
 *
 *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "protocol.h"

/*
  * Client Option Parsing (code inspired by NFS code)
  *  - a little lazy - parse all client options
  */

enum {
	Opt_msize,
	Opt_trans,
	Opt_legacy,
	Opt_version,
	Opt_err,
};

static const match_table_t tokens = {
	{Opt_msize, "msize=%u"},
	{Opt_legacy, "noextend"},
	{Opt_trans, "trans=%s"},
	{Opt_version, "version=%s"},
	{Opt_err, NULL},
};

inline int p9_is_proto_dotl(struct p9_client *clnt)
{
	return (clnt->proto_version == p9_proto_2010L);
}
EXPORT_SYMBOL(p9_is_proto_dotl);

inline int p9_is_proto_dotu(struct p9_client *clnt)
{
	return (clnt->proto_version == p9_proto_2000u);
}
EXPORT_SYMBOL(p9_is_proto_dotu);

/* Interpret mount option for protocol version */
static unsigned char get_protocol_version(const substring_t *name)
{
	unsigned char version = -EINVAL;
	if (!strncmp("9p2000", name->from, name->to-name->from)) {
		version = p9_proto_legacy;
		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: Legacy\n");
	} else if (!strncmp("9p2000.u", name->from, name->to-name->from)) {
		version = p9_proto_2000u;
		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
	} else if (!strncmp("9p2010.L", name->from, name->to-name->from)) {
		version = p9_proto_2010L;
		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: 9P2010.L\n");
	} else {
		P9_DPRINTK(P9_DEBUG_ERROR, "Unknown protocol version %s. ",
							name->from);
	}
	return version;
}

static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);

/**
 * parse_options - parse mount options into client structure
 * @opts: options string passed from mount
 * @clnt: existing v9fs client information
 *
 * Return 0 upon success, -ERRNO upon failure
 */

static int parse_opts(char *opts, struct p9_client *clnt)
{
	char *options, *tmp_options;
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	int ret = 0;

	clnt->proto_version = p9_proto_2000u;
	clnt->msize = 8192;

	if (!opts)
		return 0;

	tmp_options = kstrdup(opts, GFP_KERNEL);
	if (!tmp_options) {
		P9_DPRINTK(P9_DEBUG_ERROR,
				"failed to allocate copy of option string\n");
		return -ENOMEM;
	}
	options = tmp_options;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		if (!*p)
			continue;
		token = match_token(p, tokens, args);
		if (token < Opt_trans) {
			int r = match_int(&args[0], &option);
			if (r < 0) {
				P9_DPRINTK(P9_DEBUG_ERROR,
					"integer field, but no integer?\n");
				ret = r;
				continue;
			}
		}
		switch (token) {
		case Opt_msize:
			clnt->msize = option;
			break;
		case Opt_trans:
			clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
			if(clnt->trans_mod == NULL) {
				P9_DPRINTK(P9_DEBUG_ERROR,
				   "Could not find request transport: %s\n",
				   (char *) &args[0]);
				ret = -EINVAL;
				goto free_and_return;
			}
			break;
		case Opt_legacy:
			clnt->proto_version = p9_proto_legacy;
			break;
		case Opt_version:
			ret = get_protocol_version(&args[0]);
			if (ret == -EINVAL)
				goto free_and_return;
			clnt->proto_version = ret;
			break;
		default:
			continue;
		}
	}

free_and_return:
	kfree(tmp_options);
	return ret;
}

/**
 * p9_tag_alloc - lookup/allocate a request by tag
 * @c: client session to lookup tag within
 * @tag: numeric id for transaction
 *
 * this is a simple array lookup, but will grow the
 * request_slots as necessary to accomodate transaction
 * ids which did not previously have a slot.
 *
 * this code relies on the client spinlock to manage locks, its
 * possible we should switch to something else, but I'd rather
 * stick with something low-overhead for the common case.
 *
 */

static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
{
	unsigned long flags;
	int row, col;
	struct p9_req_t *req;

	/* This looks up the original request by tag so we know which
	 * buffer to read the data into */
	tag++;

	if (tag >= c->max_tag) {
		spin_lock_irqsave(&c->lock, flags);
		/* check again since original check was outside of lock */
		while (tag >= c->max_tag) {
			row = (tag / P9_ROW_MAXTAG);
			c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
					sizeof(struct p9_req_t), GFP_ATOMIC);

			if (!c->reqs[row]) {
				printk(KERN_ERR "Couldn't grow tag array\n");
				spin_unlock_irqrestore(&c->lock, flags);
				return ERR_PTR(-ENOMEM);
			}
			for (col = 0; col < P9_ROW_MAXTAG; col++) {
				c->reqs[row][col].status = REQ_STATUS_IDLE;
				c->reqs[row][col].tc = NULL;
			}
			c->max_tag += P9_ROW_MAXTAG;
		}
		spin_unlock_irqrestore(&c->lock, flags);
	}
	row = tag / P9_ROW_MAXTAG;
	col = tag % P9_ROW_MAXTAG;

	req = &c->reqs[row][col];
	if (!req->tc) {
		req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
		if (!req->wq) {
			printk(KERN_ERR "Couldn't grow tag array\n");
			return ERR_PTR(-ENOMEM);
		}
		init_waitqueue_head(req->wq);
		req->tc = kmalloc(sizeof(struct p9_fcall)+c->msize,
								GFP_KERNEL);
		req->rc = kmalloc(sizeof(struct p9_fcall)+c->msize,
								GFP_KERNEL);
		if ((!req->tc) || (!req->rc)) {
			printk(KERN_ERR "Couldn't grow tag array\n");
			kfree(req->tc);
			kfree(req->rc);
			kfree(req->wq);
			req->tc = req->rc = NULL;
			req->wq = NULL;
			return ERR_PTR(-ENOMEM);
		}
		req->tc->sdata = (char *) req->tc + sizeof(struct p9_fcall);
		req->tc->capacity = c->msize;
		req->rc->sdata = (char *) req->rc + sizeof(struct p9_fcall);
		req->rc->capacity = c->msize;
	}

	p9pdu_reset(req->tc);
	p9pdu_reset(req->rc);

	req->tc->tag = tag-1;
	req->status = REQ_STATUS_ALLOC;

	return &c->reqs[row][col];
}

/**
 * p9_tag_lookup - lookup a request by tag
 * @c: client session to lookup tag within
 * @tag: numeric id for transaction
 *
 */

struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
{
	int row, col;

	/* This looks up the original request by tag so we know which
	 * buffer to read the data into */
	tag++;

	BUG_ON(tag >= c->max_tag);

	row = tag / P9_ROW_MAXTAG;
	col = tag % P9_ROW_MAXTAG;

	return &c->reqs[row][col];
}
EXPORT_SYMBOL(p9_tag_lookup);

/**
 * p9_tag_init - setup tags structure and contents
 * @c:  v9fs client struct
 *
 * This initializes the tags structure for each client instance.
 *
 */

static int p9_tag_init(struct p9_client *c)
{
	int err = 0;

	c->tagpool = p9_idpool_create();
	if (IS_ERR(c->tagpool)) {
		err = PTR_ERR(c->tagpool);
		c->tagpool = NULL;
		goto error;
	}

	p9_idpool_get(c->tagpool); /* reserve tag 0 */

	c->max_tag = 0;
error:
	return err;
}

/**
 * p9_tag_cleanup - cleans up tags structure and reclaims resources
 * @c:  v9fs client struct
 *
 * This frees resources associated with the tags structure
 *
 */
static void p9_tag_cleanup(struct p9_client *c)
{
	int row, col;

	/* check to insure all requests are idle */
	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
		for (col = 0; col < P9_ROW_MAXTAG; col++) {
			if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
				P9_DPRINTK(P9_DEBUG_MUX,
				  "Attempting to cleanup non-free tag %d,%d\n",
				  row, col);
				/* TODO: delay execution of cleanup */
				return;
			}
		}
	}

	if (c->tagpool)
		p9_idpool_destroy(c->tagpool);

	/* free requests associated with tags */
	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
		for (col = 0; col < P9_ROW_MAXTAG; col++) {
			kfree(c->reqs[row][col].wq);
			kfree(c->reqs[row][col].tc);
			kfree(c->reqs[row][col].rc);
		}
		kfree(c->reqs[row]);
	}
	c->max_tag = 0;
}

/**
 * p9_free_req - free a request and clean-up as necessary
 * c: client state
 * r: request to release
 *
 */

static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
{
	int tag = r->tc->tag;
	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);

	r->status = REQ_STATUS_IDLE;
	if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
		p9_idpool_put(tag, c->tagpool);
}

/**
 * p9_client_cb - call back from transport to client
 * c: client state
 * req: request received
 *
 */
void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
{
	P9_DPRINTK(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
	wake_up(req->wq);
	P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
}
EXPORT_SYMBOL(p9_client_cb);

/**
 * p9_parse_header - parse header arguments out of a packet
 * @pdu: packet to parse
 * @size: size of packet
 * @type: type of request
 * @tag: tag of packet
 * @rewind: set if we need to rewind offset afterwards
 */

int
p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
								int rewind)
{
	int8_t r_type;
	int16_t r_tag;
	int32_t r_size;
	int offset = pdu->offset;
	int err;

	pdu->offset = 0;
	if (pdu->size == 0)
		pdu->size = 7;

	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
	if (err)
		goto rewind_and_exit;

	pdu->size = r_size;
	pdu->id = r_type;
	pdu->tag = r_tag;

	P9_DPRINTK(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n", pdu->size,
							pdu->id, pdu->tag);

	if (type)
		*type = r_type;
	if (tag)
		*tag = r_tag;
	if (size)
		*size = r_size;


rewind_and_exit:
	if (rewind)
		pdu->offset = offset;
	return err;
}
EXPORT_SYMBOL(p9_parse_header);

/**
 * p9_check_errors - check 9p packet for error return and process it
 * @c: current client instance
 * @req: request to parse and check for error conditions
 *
 * returns error code if one is discovered, otherwise returns 0
 *
 * this will have to be more complicated if we have multiple
 * error packet types
 */

static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
{
	int8_t type;
	int err;

	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
	if (err) {
		P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
		return err;
	}

	if (type == P9_RERROR) {
		int ecode;
		char *ename;

		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
							&ename, &ecode);
		if (err) {
			P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n",
									err);
			return err;
		}

		if (p9_is_proto_dotu(c))
			err = -ecode;

		if (!err || !IS_ERR_VALUE(err))
			err = p9_errstr2errno(ename, strlen(ename));

		P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode, ename);

		kfree(ename);
	} else
		err = 0;

	return err;
}

/**
 * p9_client_flush - flush (cancel) a request
 * @c: client state
 * @oldreq: request to cancel
 *
 * This sents a flush for a particular requests and links
 * the flush request to the original request.  The current
 * code only supports a single flush request although the protocol
 * allows for multiple flush requests to be sent for a single request.
 *
 */

static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
{
	struct p9_req_t *req;
	int16_t oldtag;
	int err;

	err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
	if (err)
		return err;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);

	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
	if (IS_ERR(req))
		return PTR_ERR(req);


	/* if we haven't received a response for oldreq,
	   remove it from the list. */
	spin_lock(&c->lock);
	if (oldreq->status == REQ_STATUS_FLSH)
		list_del(&oldreq->req_list);
	spin_unlock(&c->lock);

	p9_free_req(c, req);
	return 0;
}

/**
 * p9_client_rpc - issue a request and wait for a response
 * @c: client session
 * @type: type of request
 * @fmt: protocol format string (see protocol.c)
 *
 * Returns request structure (which client must free using p9_free_req)
 */

static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
{
	va_list ap;
	int tag, err;
	struct p9_req_t *req;
	unsigned long flags;
	int sigpending;

	P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);

	if (c->status != Connected)
		return ERR_PTR(-EIO);

	if (signal_pending(current)) {
		sigpending = 1;
		clear_thread_flag(TIF_SIGPENDING);
	} else
		sigpending = 0;

	tag = P9_NOTAG;
	if (type != P9_TVERSION) {
		tag = p9_idpool_get(c->tagpool);
		if (tag < 0)
			return ERR_PTR(-ENOMEM);
	}

	req = p9_tag_alloc(c, tag);
	if (IS_ERR(req))
		return req;

	/* marshall the data */
	p9pdu_prepare(req->tc, tag, type);
	va_start(ap, fmt);
	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
	va_end(ap);
	p9pdu_finalize(req->tc);

	err = c->trans_mod->request(c, req);
	if (err < 0) {
		c->status = Disconnected;
		goto reterr;
	}

	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);
	err = wait_event_interruptible(*req->wq,
						req->status >= REQ_STATUS_RCVD);
	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",
						req->wq, tag, err);

	if (req->status == REQ_STATUS_ERROR) {
		P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
		err = req->t_err;
	}

	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
		P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
		sigpending = 1;
		clear_thread_flag(TIF_SIGPENDING);

		if (c->trans_mod->cancel(c, req))
			p9_client_flush(c, req);

		/* if we received the response anyway, don't signal error */
		if (req->status == REQ_STATUS_RCVD)
			err = 0;
	}

	if (sigpending) {
		spin_lock_irqsave(&current->sighand->siglock, flags);
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, flags);
	}

	if (err < 0)
		goto reterr;

	err = p9_check_errors(c, req);
	if (!err) {
		P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d\n", c, type);
		return req;
	}

reterr:
	P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d error: %d\n", c, type,
									err);
	p9_free_req(c, req);
	return ERR_PTR(err);
}

static struct p9_fid *p9_fid_create(struct p9_client *clnt)
{
	int ret;
	struct p9_fid *fid;
	unsigned long flags;

	P9_DPRINTK(P9_DEBUG_FID, "clnt %p\n", clnt);
	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
	if (!fid)
		return ERR_PTR(-ENOMEM);

	ret = p9_idpool_get(clnt->fidpool);
	if (ret < 0) {
		ret = -ENOSPC;
		goto error;
	}
	fid->fid = ret;

	memset(&fid->qid, 0, sizeof(struct p9_qid));
	fid->mode = -1;
	fid->uid = current_fsuid();
	fid->clnt = clnt;
	fid->rdir = NULL;
	spin_lock_irqsave(&clnt->lock, flags);
	list_add(&fid->flist, &clnt->fidlist);
	spin_unlock_irqrestore(&clnt->lock, flags);

	return fid;

error:
	kfree(fid);
	return ERR_PTR(ret);
}

static void p9_fid_destroy(struct p9_fid *fid)
{
	struct p9_client *clnt;
	unsigned long flags;

	P9_DPRINTK(P9_DEBUG_FID, "fid %d\n", fid->fid);
	clnt = fid->clnt;
	p9_idpool_put(fid->fid, clnt->fidpool);
	spin_lock_irqsave(&clnt->lock, flags);
	list_del(&fid->flist);
	spin_unlock_irqrestore(&clnt->lock, flags);
	kfree(fid->rdir);
	kfree(fid);
}

int p9_client_version(struct p9_client *c)
{
	int err = 0;
	struct p9_req_t *req;
	char *version;
	int msize;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
						c->msize, c->proto_version);

	switch (c->proto_version) {
	case p9_proto_2010L:
		req = p9_client_rpc(c, P9_TVERSION, "ds",
					c->msize, "9P2010.L");
		break;
	case p9_proto_2000u:
		req = p9_client_rpc(c, P9_TVERSION, "ds",
					c->msize, "9P2000.u");
		break;
	case p9_proto_legacy:
		req = p9_client_rpc(c, P9_TVERSION, "ds",
					c->msize, "9P2000");
		break;
	default:
		return -EINVAL;
		break;
	}

	if (IS_ERR(req))
		return PTR_ERR(req);

	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
	if (err) {
		P9_DPRINTK(P9_DEBUG_9P, "version error %d\n", err);
		p9pdu_dump(1, req->rc);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
	if (!strncmp(version, "9P2010.L", 8))
		c->proto_version = p9_proto_2010L;
	else if (!strncmp(version, "9P2000.u", 8))
		c->proto_version = p9_proto_2000u;
	else if (!strncmp(version, "9P2000", 6))
		c->proto_version = p9_proto_legacy;
	else {
		err = -EREMOTEIO;
		goto error;
	}

	if (msize < c->msize)
		c->msize = msize;

error:
	kfree(version);
	p9_free_req(c, req);

	return err;
}
EXPORT_SYMBOL(p9_client_version);

struct p9_client *p9_client_create(const char *dev_name, char *options)
{
	int err;
	struct p9_client *clnt;

	err = 0;
	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
	if (!clnt)
		return ERR_PTR(-ENOMEM);

	clnt->trans_mod = NULL;
	clnt->trans = NULL;
	spin_lock_init(&clnt->lock);
	INIT_LIST_HEAD(&clnt->fidlist);

	p9_tag_init(clnt);

	err = parse_opts(options, clnt);
	if (err < 0)
		goto free_client;

	if (!clnt->trans_mod)
		clnt->trans_mod = v9fs_get_default_trans();

	if (clnt->trans_mod == NULL) {
		err = -EPROTONOSUPPORT;
		P9_DPRINTK(P9_DEBUG_ERROR,
				"No transport defined or default transport\n");
		goto free_client;
	}

	clnt->fidpool = p9_idpool_create();
	if (IS_ERR(clnt->fidpool)) {
		err = PTR_ERR(clnt->fidpool);
		clnt->fidpool = NULL;
		goto put_trans;
	}

	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
		clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);

	err = clnt->trans_mod->create(clnt, dev_name, options);
	if (err)
		goto destroy_fidpool;

	if ((clnt->msize+P9_IOHDRSZ) > clnt->trans_mod->maxsize)
		clnt->msize = clnt->trans_mod->maxsize-P9_IOHDRSZ;

	err = p9_client_version(clnt);
	if (err)
		goto close_trans;

	return clnt;

close_trans:
	clnt->trans_mod->close(clnt);
destroy_fidpool:
	p9_idpool_destroy(clnt->fidpool);
put_trans:
	v9fs_put_trans(clnt->trans_mod);
free_client:
	kfree(clnt);
	return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_create);

void p9_client_destroy(struct p9_client *clnt)
{
	struct p9_fid *fid, *fidptr;

	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p\n", clnt);

	if (clnt->trans_mod)
		clnt->trans_mod->close(clnt);

	v9fs_put_trans(clnt->trans_mod);

	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
		p9_fid_destroy(fid);

	if (clnt->fidpool)
		p9_idpool_destroy(clnt->fidpool);

	p9_tag_cleanup(clnt);

	kfree(clnt);
}
EXPORT_SYMBOL(p9_client_destroy);

void p9_client_disconnect(struct p9_client *clnt)
{
	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
	clnt->status = Disconnected;
}
EXPORT_SYMBOL(p9_client_disconnect);

struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
	char *uname, u32 n_uname, char *aname)
{
	int err;
	struct p9_req_t *req;
	struct p9_fid *fid;
	struct p9_qid qid;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
					afid ? afid->fid : -1, uname, aname);
	err = 0;

	fid = p9_fid_create(clnt);
	if (IS_ERR(fid)) {
		err = PTR_ERR(fid);
		fid = NULL;
		goto error;
	}

	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?d", fid->fid,
			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
	if (err) {
		p9pdu_dump(1, req->rc);
		p9_free_req(clnt, req);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
					qid.type,
					(unsigned long long)qid.path,
					qid.version);

	memmove(&fid->qid, &qid, sizeof(struct p9_qid));

	p9_free_req(clnt, req);
	return fid;

error:
	if (fid)
		p9_fid_destroy(fid);
	return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_attach);

struct p9_fid *
p9_client_auth(struct p9_client *clnt, char *uname, u32 n_uname, char *aname)
{
	int err;
	struct p9_req_t *req;
	struct p9_qid qid;
	struct p9_fid *afid;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TAUTH uname %s aname %s\n", uname, aname);
	err = 0;

	afid = p9_fid_create(clnt);
	if (IS_ERR(afid)) {
		err = PTR_ERR(afid);
		afid = NULL;
		goto error;
	}

	req = p9_client_rpc(clnt, P9_TAUTH, "dss?d",
			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
	if (err) {
		p9pdu_dump(1, req->rc);
		p9_free_req(clnt, req);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RAUTH qid %x.%llx.%x\n",
					qid.type,
					(unsigned long long)qid.path,
					qid.version);

	memmove(&afid->qid, &qid, sizeof(struct p9_qid));
	p9_free_req(clnt, req);
	return afid;

error:
	if (afid)
		p9_fid_destroy(afid);
	return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_auth);

struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
	int clone)
{
	int err;
	struct p9_client *clnt;
	struct p9_fid *fid;
	struct p9_qid *wqids;
	struct p9_req_t *req;
	int16_t nwqids, count;

	err = 0;
	clnt = oldfid->clnt;
	if (clone) {
		fid = p9_fid_create(clnt);
		if (IS_ERR(fid)) {
			err = PTR_ERR(fid);
			fid = NULL;
			goto error;
		}

		fid->uid = oldfid->uid;
	} else
		fid = oldfid;


	P9_DPRINTK(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %d wname[0] %s\n",
		oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);

	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
								nwname, wnames);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
	if (err) {
		p9pdu_dump(1, req->rc);
		p9_free_req(clnt, req);
		goto clunk_fid;
	}
	p9_free_req(clnt, req);

	P9_DPRINTK(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);

	if (nwqids != nwname) {
		err = -ENOENT;
		goto clunk_fid;
	}

	for (count = 0; count < nwqids; count++)
		P9_DPRINTK(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
			count, wqids[count].type,
			(unsigned long long)wqids[count].path,
			wqids[count].version);

	if (nwname)
		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
	else
		fid->qid = oldfid->qid;

	return fid;

clunk_fid:
	p9_client_clunk(fid);
	fid = NULL;

error:
	if (fid && (fid != oldfid))
		p9_fid_destroy(fid);

	return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_walk);

int p9_client_open(struct p9_fid *fid, int mode)
{
	int err;
	struct p9_client *clnt;
	struct p9_req_t *req;
	struct p9_qid qid;
	int iounit;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TOPEN fid %d mode %d\n", fid->fid, mode);
	err = 0;
	clnt = fid->clnt;

	if (fid->mode != -1)
		return -EINVAL;

	req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
	if (err) {
		p9pdu_dump(1, req->rc);
		goto free_and_error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< ROPEN qid %x.%llx.%x iounit %x\n",
				qid.type,
				(unsigned long long)qid.path,
				qid.version, iounit);

	fid->mode = mode;
	fid->iounit = iounit;

free_and_error:
	p9_free_req(clnt, req);
error:
	return err;
}
EXPORT_SYMBOL(p9_client_open);

int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
		     char *extension)
{
	int err;
	struct p9_client *clnt;
	struct p9_req_t *req;
	struct p9_qid qid;
	int iounit;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
						fid->fid, name, perm, mode);
	err = 0;
	clnt = fid->clnt;

	if (fid->mode != -1)
		return -EINVAL;

	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
				mode, extension);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
	if (err) {
		p9pdu_dump(1, req->rc);
		goto free_and_error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
				qid.type,
				(unsigned long long)qid.path,
				qid.version, iounit);

	fid->mode = mode;
	fid->iounit = iounit;

free_and_error:
	p9_free_req(clnt, req);
error:
	return err;
}
EXPORT_SYMBOL(p9_client_fcreate);

int p9_client_clunk(struct p9_fid *fid)
{
	int err;
	struct p9_client *clnt;
	struct p9_req_t *req;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TCLUNK fid %d\n", fid->fid);
	err = 0;
	clnt = fid->clnt;

	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);

	p9_free_req(clnt, req);
	p9_fid_destroy(fid);

error:
	return err;
}
EXPORT_SYMBOL(p9_client_clunk);

int p9_client_remove(struct p9_fid *fid)
{
	int err;
	struct p9_client *clnt;
	struct p9_req_t *req;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
	err = 0;
	clnt = fid->clnt;

	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);

	p9_free_req(clnt, req);
	p9_fid_destroy(fid);

error:
	return err;
}
EXPORT_SYMBOL(p9_client_remove);

int
p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
								u32 count)
{
	int err, rsize, total;
	struct p9_client *clnt;
	struct p9_req_t *req;
	char *dataptr;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", fid->fid,
					(long long unsigned) offset, count);
	err = 0;
	clnt = fid->clnt;
	total = 0;

	rsize = fid->iounit;
	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
		rsize = clnt->msize - P9_IOHDRSZ;

	if (count < rsize)
		rsize = count;

	req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
	if (err) {
		p9pdu_dump(1, req->rc);
		goto free_and_error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RREAD count %d\n", count);

	if (data) {
		memmove(data, dataptr, count);
	}

	if (udata) {
		err = copy_to_user(udata, dataptr, count);
		if (err) {
			err = -EFAULT;
			goto free_and_error;
		}
	}

	p9_free_req(clnt, req);
	return count;

free_and_error:
	p9_free_req(clnt, req);
error:
	return err;
}
EXPORT_SYMBOL(p9_client_read);

int
p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
							u64 offset, u32 count)
{
	int err, rsize, total;
	struct p9_client *clnt;
	struct p9_req_t *req;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
				fid->fid, (long long unsigned) offset, count);
	err = 0;
	clnt = fid->clnt;
	total = 0;

	rsize = fid->iounit;
	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
		rsize = clnt->msize - P9_IOHDRSZ;

	if (count < rsize)
		rsize = count;
	if (data)
		req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid, offset,
								rsize, data);
	else
		req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid, offset,
								rsize, udata);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
	if (err) {
		p9pdu_dump(1, req->rc);
		goto free_and_error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);

	p9_free_req(clnt, req);
	return count;

free_and_error:
	p9_free_req(clnt, req);
error:
	return err;
}
EXPORT_SYMBOL(p9_client_write);

struct p9_wstat *p9_client_stat(struct p9_fid *fid)
{
	int err;
	struct p9_client *clnt;
	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
	struct p9_req_t *req;
	u16 ignored;

	P9_DPRINTK(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);

	if (!ret)
		return ERR_PTR(-ENOMEM);

	err = 0;
	clnt = fid->clnt;

	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
	if (err) {
		p9pdu_dump(1, req->rc);
		p9_free_req(clnt, req);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P,
		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
		"<<<    uid=%d gid=%d n_muid=%d\n",
		ret->size, ret->type, ret->dev, ret->qid.type,
		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
		ret->atime, ret->mtime, (unsigned long long)ret->length,
		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
		ret->n_uid, ret->n_gid, ret->n_muid);

	p9_free_req(clnt, req);
	return ret;

error:
	kfree(ret);
	return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_stat);

static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
{
	int ret;

	/* NOTE: size shouldn't include its own length */
	/* size[2] type[2] dev[4] qid[13] */
	/* mode[4] atime[4] mtime[4] length[8]*/
	/* name[s] uid[s] gid[s] muid[s] */
	ret = 2+4+13+4+4+4+8+2+2+2+2;

	if (wst->name)
		ret += strlen(wst->name);
	if (wst->uid)
		ret += strlen(wst->uid);
	if (wst->gid)
		ret += strlen(wst->gid);
	if (wst->muid)
		ret += strlen(wst->muid);

	if (proto_version == p9_proto_2000u) {
		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
		if (wst->extension)
			ret += strlen(wst->extension);
	}

	return ret;
}

int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
{
	int err;
	struct p9_req_t *req;
	struct p9_client *clnt;

	err = 0;
	clnt = fid->clnt;
	wst->size = p9_client_statsize(wst, clnt->proto_version);
	P9_DPRINTK(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
	P9_DPRINTK(P9_DEBUG_9P,
		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
		"     uid=%d gid=%d n_muid=%d\n",
		wst->size, wst->type, wst->dev, wst->qid.type,
		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
		wst->atime, wst->mtime, (unsigned long long)wst->length,
		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
		wst->n_uid, wst->n_gid, wst->n_muid);

	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto error;
	}

	P9_DPRINTK(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);

	p9_free_req(clnt, req);
error:
	return err;
}
EXPORT_SYMBOL(p9_client_wstat);