summaryrefslogtreecommitdiff
path: root/drivers/mtd/ubi/cdev.c
blob: f4061126926bdb231493e318f7e9c5978a9b88ff (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
/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 */

/*
 * This file includes implementation of UBI character device operations.
 *
 * There are two kinds of character devices in UBI: UBI character devices and
 * UBI volume character devices. UBI character devices allow users to
 * manipulate whole volumes: create, remove, and re-size them. Volume character
 * devices provide volume I/O capabilities.
 *
 * Major and minor numbers are assigned dynamically to both UBI and volume
 * character devices.
 *
 * Well, there is the third kind of character devices - the UBI control
 * character device, which allows to manipulate by UBI devices - create and
 * delete them. In other words, it is used for attaching and detaching MTD
 * devices.
 */

#include <linux/module.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/ioctl.h>
#include <linux/capability.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include <linux/math64.h>
#include <mtd/ubi-user.h>
#include "ubi.h"

/**
 * get_exclusive - get exclusive access to an UBI volume.
 * @desc: volume descriptor
 *
 * This function changes UBI volume open mode to "exclusive". Returns previous
 * mode value (positive integer) in case of success and a negative error code
 * in case of failure.
 */
static int get_exclusive(struct ubi_volume_desc *desc)
{
	int users, err;
	struct ubi_volume *vol = desc->vol;

	spin_lock(&vol->ubi->volumes_lock);
	users = vol->readers + vol->writers + vol->exclusive;
	ubi_assert(users > 0);
	if (users > 1) {
		dbg_err("%d users for volume %d", users, vol->vol_id);
		err = -EBUSY;
	} else {
		vol->readers = vol->writers = 0;
		vol->exclusive = 1;
		err = desc->mode;
		desc->mode = UBI_EXCLUSIVE;
	}
	spin_unlock(&vol->ubi->volumes_lock);

	return err;
}

/**
 * revoke_exclusive - revoke exclusive mode.
 * @desc: volume descriptor
 * @mode: new mode to switch to
 */
static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
{
	struct ubi_volume *vol = desc->vol;

	spin_lock(&vol->ubi->volumes_lock);
	ubi_assert(vol->readers == 0 && vol->writers == 0);
	ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
	vol->exclusive = 0;
	if (mode == UBI_READONLY)
		vol->readers = 1;
	else if (mode == UBI_READWRITE)
		vol->writers = 1;
	else
		vol->exclusive = 1;
	spin_unlock(&vol->ubi->volumes_lock);

	desc->mode = mode;
}

static int vol_cdev_open(struct inode *inode, struct file *file)
{
	struct ubi_volume_desc *desc;
	int vol_id = iminor(inode) - 1, mode, ubi_num;

	ubi_num = ubi_major2num(imajor(inode));
	if (ubi_num < 0)
		return ubi_num;

	if (file->f_mode & FMODE_WRITE)
		mode = UBI_READWRITE;
	else
		mode = UBI_READONLY;

	dbg_gen("open device %d, volume %d, mode %d",
		ubi_num, vol_id, mode);

	desc = ubi_open_volume(ubi_num, vol_id, mode);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	file->private_data = desc;
	return 0;
}

static int vol_cdev_release(struct inode *inode, struct file *file)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;

	dbg_gen("release device %d, volume %d, mode %d",
		vol->ubi->ubi_num, vol->vol_id, desc->mode);

	if (vol->updating) {
		ubi_warn("update of volume %d not finished, volume is damaged",
			 vol->vol_id);
		ubi_assert(!vol->changing_leb);
		vol->updating = 0;
		vfree(vol->upd_buf);
	} else if (vol->changing_leb) {
		dbg_gen("only %lld of %lld bytes received for atomic LEB change"
			" for volume %d:%d, cancel", vol->upd_received,
			vol->upd_bytes, vol->ubi->ubi_num, vol->vol_id);
		vol->changing_leb = 0;
		vfree(vol->upd_buf);
	}

	ubi_close_volume(desc);
	return 0;
}

static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	loff_t new_offset;

	if (vol->updating) {
		/* Update is in progress, seeking is prohibited */
		dbg_err("updating");
		return -EBUSY;
	}

	switch (origin) {
	case 0: /* SEEK_SET */
		new_offset = offset;
		break;
	case 1: /* SEEK_CUR */
		new_offset = file->f_pos + offset;
		break;
	case 2: /* SEEK_END */
		new_offset = vol->used_bytes + offset;
		break;
	default:
		return -EINVAL;
	}

	if (new_offset < 0 || new_offset > vol->used_bytes) {
		dbg_err("bad seek %lld", new_offset);
		return -EINVAL;
	}

	dbg_gen("seek volume %d, offset %lld, origin %d, new offset %lld",
		vol->vol_id, offset, origin, new_offset);

	file->f_pos = new_offset;
	return new_offset;
}

static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_device *ubi = desc->vol->ubi;
	struct inode *inode = file->f_path.dentry->d_inode;
	int err;
	mutex_lock(&inode->i_mutex);
	err = ubi_sync(ubi->ubi_num);
	mutex_unlock(&inode->i_mutex);
	return err;
}


static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
			     loff_t *offp)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;
	int err, lnum, off, len,  tbuf_size;
	size_t count_save = count;
	void *tbuf;

	dbg_gen("read %zd bytes from offset %lld of volume %d",
		count, *offp, vol->vol_id);

	if (vol->updating) {
		dbg_err("updating");
		return -EBUSY;
	}
	if (vol->upd_marker) {
		dbg_err("damaged volume, update marker is set");
		return -EBADF;
	}
	if (*offp == vol->used_bytes || count == 0)
		return 0;

	if (vol->corrupted)
		dbg_gen("read from corrupted volume %d", vol->vol_id);

	if (*offp + count > vol->used_bytes)
		count_save = count = vol->used_bytes - *offp;

	tbuf_size = vol->usable_leb_size;
	if (count < tbuf_size)
		tbuf_size = ALIGN(count, ubi->min_io_size);
	tbuf = vmalloc(tbuf_size);
	if (!tbuf)
		return -ENOMEM;

	len = count > tbuf_size ? tbuf_size : count;
	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);

	do {
		cond_resched();

		if (off + len >= vol->usable_leb_size)
			len = vol->usable_leb_size - off;

		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
		if (err)
			break;

		off += len;
		if (off == vol->usable_leb_size) {
			lnum += 1;
			off -= vol->usable_leb_size;
		}

		count -= len;
		*offp += len;

		err = copy_to_user(buf, tbuf, len);
		if (err) {
			err = -EFAULT;
			break;
		}

		buf += len;
		len = count > tbuf_size ? tbuf_size : count;
	} while (count);

	vfree(tbuf);
	return err ? err : count_save - count;
}

/*
 * This function allows to directly write to dynamic UBI volumes, without
 * issuing the volume update operation.
 */
static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
				     size_t count, loff_t *offp)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;
	int lnum, off, len, tbuf_size, err = 0;
	size_t count_save = count;
	char *tbuf;

	if (!vol->direct_writes)
		return -EPERM;

	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
		count, *offp, vol->vol_id);

	if (vol->vol_type == UBI_STATIC_VOLUME)
		return -EROFS;

	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
	if (off & (ubi->min_io_size - 1)) {
		dbg_err("unaligned position");
		return -EINVAL;
	}

	if (*offp + count > vol->used_bytes)
		count_save = count = vol->used_bytes - *offp;

	/* We can write only in fractions of the minimum I/O unit */
	if (count & (ubi->min_io_size - 1)) {
		dbg_err("unaligned write length");
		return -EINVAL;
	}

	tbuf_size = vol->usable_leb_size;
	if (count < tbuf_size)
		tbuf_size = ALIGN(count, ubi->min_io_size);
	tbuf = vmalloc(tbuf_size);
	if (!tbuf)
		return -ENOMEM;

	len = count > tbuf_size ? tbuf_size : count;

	while (count) {
		cond_resched();

		if (off + len >= vol->usable_leb_size)
			len = vol->usable_leb_size - off;

		err = copy_from_user(tbuf, buf, len);
		if (err) {
			err = -EFAULT;
			break;
		}

		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
		if (err)
			break;

		off += len;
		if (off == vol->usable_leb_size) {
			lnum += 1;
			off -= vol->usable_leb_size;
		}

		count -= len;
		*offp += len;
		buf += len;
		len = count > tbuf_size ? tbuf_size : count;
	}

	vfree(tbuf);
	return err ? err : count_save - count;
}

static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
			      size_t count, loff_t *offp)
{
	int err = 0;
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;

	if (!vol->updating && !vol->changing_leb)
		return vol_cdev_direct_write(file, buf, count, offp);

	if (vol->updating)
		err = ubi_more_update_data(ubi, vol, buf, count);
	else
		err = ubi_more_leb_change_data(ubi, vol, buf, count);

	if (err < 0) {
		ubi_err("cannot accept more %zd bytes of data, error %d",
			count, err);
		return err;
	}

	if (err) {
		/*
		 * The operation is finished, @err contains number of actually
		 * written bytes.
		 */
		count = err;

		if (vol->changing_leb) {
			revoke_exclusive(desc, UBI_READWRITE);
			return count;
		}

		err = ubi_check_volume(ubi, vol->vol_id);
		if (err < 0)
			return err;

		if (err) {
			ubi_warn("volume %d on UBI device %d is corrupted",
				 vol->vol_id, ubi->ubi_num);
			vol->corrupted = 1;
		}
		vol->checked = 1;
		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
		revoke_exclusive(desc, UBI_READWRITE);
	}

	return count;
}

static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
			   unsigned long arg)
{
	int err = 0;
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	/* Volume update command */
	case UBI_IOCVOLUP:
	{
		int64_t bytes, rsvd_bytes;

		if (!capable(CAP_SYS_RESOURCE)) {
			err = -EPERM;
			break;
		}

		err = copy_from_user(&bytes, argp, sizeof(int64_t));
		if (err) {
			err = -EFAULT;
			break;
		}

		if (desc->mode == UBI_READONLY) {
			err = -EROFS;
			break;
		}

		rsvd_bytes = (long long)vol->reserved_pebs *
					ubi->leb_size-vol->data_pad;
		if (bytes < 0 || bytes > rsvd_bytes) {
			err = -EINVAL;
			break;
		}

		err = get_exclusive(desc);
		if (err < 0)
			break;

		err = ubi_start_update(ubi, vol, bytes);
		if (bytes == 0)
			revoke_exclusive(desc, UBI_READWRITE);
		break;
	}

	/* Atomic logical eraseblock change command */
	case UBI_IOCEBCH:
	{
		struct ubi_leb_change_req req;

		err = copy_from_user(&req, argp,
				     sizeof(struct ubi_leb_change_req));
		if (err) {
			err = -EFAULT;
			break;
		}

		if (desc->mode == UBI_READONLY ||
		    vol->vol_type == UBI_STATIC_VOLUME) {
			err = -EROFS;
			break;
		}

		/* Validate the request */
		err = -EINVAL;
		if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
		    req.bytes < 0 || req.lnum >= vol->usable_leb_size)
			break;

		err = get_exclusive(desc);
		if (err < 0)
			break;

		err = ubi_start_leb_change(ubi, vol, &req);
		if (req.bytes == 0)
			revoke_exclusive(desc, UBI_READWRITE);
		break;
	}

	/* Logical eraseblock erasure command */
	case UBI_IOCEBER:
	{
		int32_t lnum;

		err = get_user(lnum, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}

		if (desc->mode == UBI_READONLY ||
		    vol->vol_type == UBI_STATIC_VOLUME) {
			err = -EROFS;
			break;
		}

		if (lnum < 0 || lnum >= vol->reserved_pebs) {
			err = -EINVAL;
			break;
		}

		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
		err = ubi_eba_unmap_leb(ubi, vol, lnum);
		if (err)
			break;

		err = ubi_wl_flush(ubi);
		break;
	}

	/* Logical eraseblock map command */
	case UBI_IOCEBMAP:
	{
		struct ubi_map_req req;

		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
		if (err) {
			err = -EFAULT;
			break;
		}
		err = ubi_leb_map(desc, req.lnum);
		break;
	}

	/* Logical eraseblock un-map command */
	case UBI_IOCEBUNMAP:
	{
		int32_t lnum;

		err = get_user(lnum, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}
		err = ubi_leb_unmap(desc, lnum);
		break;
	}

	/* Check if logical eraseblock is mapped command */
	case UBI_IOCEBISMAP:
	{
		int32_t lnum;

		err = get_user(lnum, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}
		err = ubi_is_mapped(desc, lnum);
		break;
	}

	/* Set volume property command */
	case UBI_IOCSETVOLPROP:
	{
		struct ubi_set_vol_prop_req req;

		err = copy_from_user(&req, argp,
				     sizeof(struct ubi_set_vol_prop_req));
		if (err) {
			err = -EFAULT;
			break;
		}
		switch (req.property) {
		case UBI_VOL_PROP_DIRECT_WRITE:
			mutex_lock(&ubi->device_mutex);
			desc->vol->direct_writes = !!req.value;
			mutex_unlock(&ubi->device_mutex);
			break;
		default:
			err = -EINVAL;
			break;
		}
		break;
	}

	default:
		err = -ENOTTY;
		break;
	}
	return err;
}

/**
 * verify_mkvol_req - verify volume creation request.
 * @ubi: UBI device description object
 * @req: the request to check
 *
 * This function zero if the request is correct, and %-EINVAL if not.
 */
static int verify_mkvol_req(const struct ubi_device *ubi,
			    const struct ubi_mkvol_req *req)
{
	int n, err = -EINVAL;

	if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
	    req->name_len < 0)
		goto bad;

	if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
	    req->vol_id != UBI_VOL_NUM_AUTO)
		goto bad;

	if (req->alignment == 0)
		goto bad;

	if (req->bytes == 0)
		goto bad;

	if (req->vol_type != UBI_DYNAMIC_VOLUME &&
	    req->vol_type != UBI_STATIC_VOLUME)
		goto bad;

	if (req->alignment > ubi->leb_size)
		goto bad;

	n = req->alignment & (ubi->min_io_size - 1);
	if (req->alignment != 1 && n)
		goto bad;

	if (!req->name[0] || !req->name_len)
		goto bad;

	if (req->name_len > UBI_VOL_NAME_MAX) {
		err = -ENAMETOOLONG;
		goto bad;
	}

	n = strnlen(req->name, req->name_len + 1);
	if (n != req->name_len)
		goto bad;

	return 0;

bad:
	dbg_err("bad volume creation request");
	ubi_dbg_dump_mkvol_req(req);
	return err;
}

/**
 * verify_rsvol_req - verify volume re-size request.
 * @ubi: UBI device description object
 * @req: the request to check
 *
 * This function returns zero if the request is correct, and %-EINVAL if not.
 */
static int verify_rsvol_req(const struct ubi_device *ubi,
			    const struct ubi_rsvol_req *req)
{
	if (req->bytes <= 0)
		return -EINVAL;

	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
		return -EINVAL;

	return 0;
}

/**
 * rename_volumes - rename UBI volumes.
 * @ubi: UBI device description object
 * @req: volumes re-name request
 *
 * This is a helper function for the volume re-name IOCTL which validates the
 * the request, opens the volume and calls corresponding volumes management
 * function. Returns zero in case of success and a negative error code in case
 * of failure.
 */
static int rename_volumes(struct ubi_device *ubi,
			  struct ubi_rnvol_req *req)
{
	int i, n, err;
	struct list_head rename_list;
	struct ubi_rename_entry *re, *re1;

	if (req->count < 0 || req->count > UBI_MAX_RNVOL)
		return -EINVAL;

	if (req->count == 0)
		return 0;

	/* Validate volume IDs and names in the request */
	for (i = 0; i < req->count; i++) {
		if (req->ents[i].vol_id < 0 ||
		    req->ents[i].vol_id >= ubi->vtbl_slots)
			return -EINVAL;
		if (req->ents[i].name_len < 0)
			return -EINVAL;
		if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
			return -ENAMETOOLONG;
		req->ents[i].name[req->ents[i].name_len] = '\0';
		n = strlen(req->ents[i].name);
		if (n != req->ents[i].name_len)
			err = -EINVAL;
	}

	/* Make sure volume IDs and names are unique */
	for (i = 0; i < req->count - 1; i++) {
		for (n = i + 1; n < req->count; n++) {
			if (req->ents[i].vol_id == req->ents[n].vol_id) {
				dbg_err("duplicated volume id %d",
					req->ents[i].vol_id);
				return -EINVAL;
			}
			if (!strcmp(req->ents[i].name, req->ents[n].name)) {
				dbg_err("duplicated volume name \"%s\"",
					req->ents[i].name);
				return -EINVAL;
			}
		}
	}

	/* Create the re-name list */
	INIT_LIST_HEAD(&rename_list);
	for (i = 0; i < req->count; i++) {
		int vol_id = req->ents[i].vol_id;
		int name_len = req->ents[i].name_len;
		const char *name = req->ents[i].name;

		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
		if (!re) {
			err = -ENOMEM;
			goto out_free;
		}

		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
		if (IS_ERR(re->desc)) {
			err = PTR_ERR(re->desc);
			dbg_err("cannot open volume %d, error %d", vol_id, err);
			kfree(re);
			goto out_free;
		}

		/* Skip this re-naming if the name does not really change */
		if (re->desc->vol->name_len == name_len &&
		    !memcmp(re->desc->vol->name, name, name_len)) {
			ubi_close_volume(re->desc);
			kfree(re);
			continue;
		}

		re->new_name_len = name_len;
		memcpy(re->new_name, name, name_len);
		list_add_tail(&re->list, &rename_list);
		dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
			vol_id, re->desc->vol->name, name);
	}

	if (list_empty(&rename_list))
		return 0;

	/* Find out the volumes which have to be removed */
	list_for_each_entry(re, &rename_list, list) {
		struct ubi_volume_desc *desc;
		int no_remove_needed = 0;

		/*
		 * Volume @re->vol_id is going to be re-named to
		 * @re->new_name, while its current name is @name. If a volume
		 * with name @re->new_name currently exists, it has to be
		 * removed, unless it is also re-named in the request (@req).
		 */
		list_for_each_entry(re1, &rename_list, list) {
			if (re->new_name_len == re1->desc->vol->name_len &&
			    !memcmp(re->new_name, re1->desc->vol->name,
				    re1->desc->vol->name_len)) {
				no_remove_needed = 1;
				break;
			}
		}

		if (no_remove_needed)
			continue;

		/*
		 * It seems we need to remove volume with name @re->new_name,
		 * if it exists.
		 */
		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
					  UBI_EXCLUSIVE);
		if (IS_ERR(desc)) {
			err = PTR_ERR(desc);
			if (err == -ENODEV)
				/* Re-naming into a non-existing volume name */
				continue;

			/* The volume exists but busy, or an error occurred */
			dbg_err("cannot open volume \"%s\", error %d",
				re->new_name, err);
			goto out_free;
		}

		re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
		if (!re1) {
			err = -ENOMEM;
			ubi_close_volume(desc);
			goto out_free;
		}

		re1->remove = 1;
		re1->desc = desc;
		list_add(&re1->list, &rename_list);
		dbg_msg("will remove volume %d, name \"%s\"",
			re1->desc->vol->vol_id, re1->desc->vol->name);
	}

	mutex_lock(&ubi->device_mutex);
	err = ubi_rename_volumes(ubi, &rename_list);
	mutex_unlock(&ubi->device_mutex);

out_free:
	list_for_each_entry_safe(re, re1, &rename_list, list) {
		ubi_close_volume(re->desc);
		list_del(&re->list);
		kfree(re);
	}
	return err;
}

static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
			   unsigned long arg)
{
	int err = 0;
	struct ubi_device *ubi;
	struct ubi_volume_desc *desc;
	void __user *argp = (void __user *)arg;

	if (!capable(CAP_SYS_RESOURCE))
		return -EPERM;

	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
	if (!ubi)
		return -ENODEV;

	switch (cmd) {
	/* Create volume command */
	case UBI_IOCMKVOL:
	{
		struct ubi_mkvol_req req;

		dbg_gen("create volume");
		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
		if (err) {
			err = -EFAULT;
			break;
		}

		err = verify_mkvol_req(ubi, &req);
		if (err)
			break;

		mutex_lock(&ubi->device_mutex);
		err = ubi_create_volume(ubi, &req);
		mutex_unlock(&ubi->device_mutex);
		if (err)
			break;

		err = put_user(req.vol_id, (__user int32_t *)argp);
		if (err)
			err = -EFAULT;

		break;
	}

	/* Remove volume command */
	case UBI_IOCRMVOL:
	{
		int vol_id;

		dbg_gen("remove volume");
		err = get_user(vol_id, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}

		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
		if (IS_ERR(desc)) {
			err = PTR_ERR(desc);
			break;
		}

		mutex_lock(&ubi->device_mutex);
		err = ubi_remove_volume(desc, 0);
		mutex_unlock(&ubi->device_mutex);

		/*
		 * The volume is deleted (unless an error occurred), and the
		 * 'struct ubi_volume' object will be freed when
		 * 'ubi_close_volume()' will call 'put_device()'.
		 */
		ubi_close_volume(desc);
		break;
	}

	/* Re-size volume command */
	case UBI_IOCRSVOL:
	{
		int pebs;
		struct ubi_rsvol_req req;

		dbg_gen("re-size volume");
		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
		if (err) {
			err = -EFAULT;
			break;
		}

		err = verify_rsvol_req(ubi, &req);
		if (err)
			break;

		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
		if (IS_ERR(desc)) {
			err = PTR_ERR(desc);
			break;
		}

		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
			       desc->vol->usable_leb_size);

		mutex_lock(&ubi->device_mutex);
		err = ubi_resize_volume(desc, pebs);
		mutex_unlock(&ubi->device_mutex);
		ubi_close_volume(desc);
		break;
	}

	/* Re-name volumes command */
	case UBI_IOCRNVOL:
	{
		struct ubi_rnvol_req *req;

		dbg_msg("re-name volumes");
		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
		if (!req) {
			err = -ENOMEM;
			break;
		};

		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
		if (err) {
			err = -EFAULT;
			kfree(req);
			break;
		}

		err = rename_volumes(ubi, req);
		kfree(req);
		break;
	}

	default:
		err = -ENOTTY;
		break;
	}

	ubi_put_device(ubi);
	return err;
}

static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	int err = 0;
	void __user *argp = (void __user *)arg;

	if (!capable(CAP_SYS_RESOURCE))
		return -EPERM;

	switch (cmd) {
	/* Attach an MTD device command */
	case UBI_IOCATT:
	{
		struct ubi_attach_req req;
		struct mtd_info *mtd;

		dbg_gen("attach MTD device");
		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
		if (err) {
			err = -EFAULT;
			break;
		}

		if (req.mtd_num < 0 ||
		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
			err = -EINVAL;
			break;
		}

		mtd = get_mtd_device(NULL, req.mtd_num);
		if (IS_ERR(mtd)) {
			err = PTR_ERR(mtd);
			break;
		}

		/*
		 * Note, further request verification is done by
		 * 'ubi_attach_mtd_dev()'.
		 */
		mutex_lock(&ubi_devices_mutex);
		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
		mutex_unlock(&ubi_devices_mutex);
		if (err < 0)
			put_mtd_device(mtd);
		else
			/* @err contains UBI device number */
			err = put_user(err, (__user int32_t *)argp);

		break;
	}

	/* Detach an MTD device command */
	case UBI_IOCDET:
	{
		int ubi_num;

		dbg_gen("dettach MTD device");
		err = get_user(ubi_num, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}

		mutex_lock(&ubi_devices_mutex);
		err = ubi_detach_mtd_dev(ubi_num, 0);
		mutex_unlock(&ubi_devices_mutex);
		break;
	}

	default:
		err = -ENOTTY;
		break;
	}

	return err;
}

#ifdef CONFIG_COMPAT
static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
				  unsigned long arg)
{
	unsigned long translated_arg = (unsigned long)compat_ptr(arg);

	return vol_cdev_ioctl(file, cmd, translated_arg);
}

static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
				  unsigned long arg)
{
	unsigned long translated_arg = (unsigned long)compat_ptr(arg);

	return ubi_cdev_ioctl(file, cmd, translated_arg);
}

static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
				   unsigned long arg)
{
	unsigned long translated_arg = (unsigned long)compat_ptr(arg);

	return ctrl_cdev_ioctl(file, cmd, translated_arg);
}
#else
#define vol_cdev_compat_ioctl  NULL
#define ubi_cdev_compat_ioctl  NULL
#define ctrl_cdev_compat_ioctl NULL
#endif

/* UBI volume character device operations */
const struct file_operations ubi_vol_cdev_operations = {
	.owner          = THIS_MODULE,
	.open           = vol_cdev_open,
	.release        = vol_cdev_release,
	.llseek         = vol_cdev_llseek,
	.read           = vol_cdev_read,
	.write          = vol_cdev_write,
	.fsync		= vol_cdev_fsync,
	.unlocked_ioctl = vol_cdev_ioctl,
	.compat_ioctl   = vol_cdev_compat_ioctl,
};

/* UBI character device operations */
const struct file_operations ubi_cdev_operations = {
	.owner          = THIS_MODULE,
	.llseek         = no_llseek,
	.unlocked_ioctl = ubi_cdev_ioctl,
	.compat_ioctl   = ubi_cdev_compat_ioctl,
};

/* UBI control character device operations */
const struct file_operations ubi_ctrl_cdev_operations = {
	.owner          = THIS_MODULE,
	.unlocked_ioctl = ctrl_cdev_ioctl,
	.compat_ioctl   = ctrl_cdev_compat_ioctl,
	.llseek		= no_llseek,
};