summaryrefslogtreecommitdiffstats
path: root/drivers/md/dm-dust.c
blob: 072ea913cebc727861b3ed17deb568b4f5da9e39 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2018 Red Hat, Inc.
 *
 * This is a test "dust" device, which fails reads on specified
 * sectors, emulating the behavior of a hard disk drive sending
 * a "Read Medium Error" sense.
 *
 */

#include <linux/device-mapper.h>
#include <linux/module.h>
#include <linux/rbtree.h>

#define DM_MSG_PREFIX "dust"

struct badblock {
	struct rb_node node;
	sector_t bb;
	unsigned char wr_fail_cnt;
};

struct dust_device {
	struct dm_dev *dev;
	struct rb_root badblocklist;
	unsigned long long badblock_count;
	spinlock_t dust_lock;
	unsigned int blksz;
	int sect_per_block_shift;
	unsigned int sect_per_block;
	sector_t start;
	bool fail_read_on_bb:1;
	bool quiet_mode:1;
};

static struct badblock *dust_rb_search(struct rb_root *root, sector_t blk)
{
	struct rb_node *node = root->rb_node;

	while (node) {
		struct badblock *bblk = rb_entry(node, struct badblock, node);

		if (bblk->bb > blk)
			node = node->rb_left;
		else if (bblk->bb < blk)
			node = node->rb_right;
		else
			return bblk;
	}

	return NULL;
}

static bool dust_rb_insert(struct rb_root *root, struct badblock *new)
{
	struct badblock *bblk;
	struct rb_node **link = &root->rb_node, *parent = NULL;
	sector_t value = new->bb;

	while (*link) {
		parent = *link;
		bblk = rb_entry(parent, struct badblock, node);

		if (bblk->bb > value)
			link = &(*link)->rb_left;
		else if (bblk->bb < value)
			link = &(*link)->rb_right;
		else
			return false;
	}

	rb_link_node(&new->node, parent, link);
	rb_insert_color(&new->node, root);

	return true;
}

static int dust_remove_block(struct dust_device *dd, unsigned long long block)
{
	struct badblock *bblock;
	unsigned long flags;

	spin_lock_irqsave(&dd->dust_lock, flags);
	bblock = dust_rb_search(&dd->badblocklist, block);

	if (bblock == NULL) {
		if (!dd->quiet_mode) {
			DMERR("%s: block %llu not found in badblocklist",
			      __func__, block);
		}
		spin_unlock_irqrestore(&dd->dust_lock, flags);
		return -EINVAL;
	}

	rb_erase(&bblock->node, &dd->badblocklist);
	dd->badblock_count--;
	if (!dd->quiet_mode)
		DMINFO("%s: badblock removed at block %llu", __func__, block);
	kfree(bblock);
	spin_unlock_irqrestore(&dd->dust_lock, flags);

	return 0;
}

static int dust_add_block(struct dust_device *dd, unsigned long long block,
			  unsigned char wr_fail_cnt)
{
	struct badblock *bblock;
	unsigned long flags;

	bblock = kmalloc(sizeof(*bblock), GFP_KERNEL);
	if (bblock == NULL) {
		if (!dd->quiet_mode)
			DMERR("%s: badblock allocation failed", __func__);
		return -ENOMEM;
	}

	spin_lock_irqsave(&dd->dust_lock, flags);
	bblock->bb = block;
	bblock->wr_fail_cnt = wr_fail_cnt;
	if (!dust_rb_insert(&dd->badblocklist, bblock)) {
		if (!dd->quiet_mode) {
			DMERR("%s: block %llu already in badblocklist",
			      __func__, block);
		}
		spin_unlock_irqrestore(&dd->dust_lock, flags);
		kfree(bblock);
		return -EINVAL;
	}

	dd->badblock_count++;
	if (!dd->quiet_mode) {
		DMINFO("%s: badblock added at block %llu with write fail count %hhu",
		       __func__, block, wr_fail_cnt);
	}
	spin_unlock_irqrestore(&dd->dust_lock, flags);

	return 0;
}

static int dust_query_block(struct dust_device *dd, unsigned long long block, char *result,
			    unsigned int maxlen, unsigned int *sz_ptr)
{
	struct badblock *bblock;
	unsigned long flags;
	unsigned int sz = *sz_ptr;

	spin_lock_irqsave(&dd->dust_lock, flags);
	bblock = dust_rb_search(&dd->badblocklist, block);
	if (bblock != NULL)
		DMEMIT("%s: block %llu found in badblocklist", __func__, block);
	else
		DMEMIT("%s: block %llu not found in badblocklist", __func__, block);
	spin_unlock_irqrestore(&dd->dust_lock, flags);

	return 1;
}

static int __dust_map_read(struct dust_device *dd, sector_t thisblock)
{
	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);

	if (bblk)
		return DM_MAPIO_KILL;

	return DM_MAPIO_REMAPPED;
}

static int dust_map_read(struct dust_device *dd, sector_t thisblock,
			 bool fail_read_on_bb)
{
	unsigned long flags;
	int r = DM_MAPIO_REMAPPED;

	if (fail_read_on_bb) {
		thisblock >>= dd->sect_per_block_shift;
		spin_lock_irqsave(&dd->dust_lock, flags);
		r = __dust_map_read(dd, thisblock);
		spin_unlock_irqrestore(&dd->dust_lock, flags);
	}

	return r;
}

static int __dust_map_write(struct dust_device *dd, sector_t thisblock)
{
	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);

	if (bblk && bblk->wr_fail_cnt > 0) {
		bblk->wr_fail_cnt--;
		return DM_MAPIO_KILL;
	}

	if (bblk) {
		rb_erase(&bblk->node, &dd->badblocklist);
		dd->badblock_count--;
		kfree(bblk);
		if (!dd->quiet_mode) {
			sector_div(thisblock, dd->sect_per_block);
			DMINFO("block %llu removed from badblocklist by write",
			       (unsigned long long)thisblock);
		}
	}

	return DM_MAPIO_REMAPPED;
}

static int dust_map_write(struct dust_device *dd, sector_t thisblock,
			  bool fail_read_on_bb)
{
	unsigned long flags;
	int r = DM_MAPIO_REMAPPED;

	if (fail_read_on_bb) {
		thisblock >>= dd->sect_per_block_shift;
		spin_lock_irqsave(&dd->dust_lock, flags);
		r = __dust_map_write(dd, thisblock);
		spin_unlock_irqrestore(&dd->dust_lock, flags);
	}

	return r;
}

static int dust_map(struct dm_target *ti, struct bio *bio)
{
	struct dust_device *dd = ti->private;
	int r;

	bio_set_dev(bio, dd->dev->bdev);
	bio->bi_iter.bi_sector = dd->start + dm_target_offset(ti, bio->bi_iter.bi_sector);

	if (bio_data_dir(bio) == READ)
		r = dust_map_read(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
	else
		r = dust_map_write(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);

	return r;
}

static bool __dust_clear_badblocks(struct rb_root *tree,
				   unsigned long long count)
{
	struct rb_node *node = NULL, *nnode = NULL;

	nnode = rb_first(tree);
	if (nnode == NULL) {
		BUG_ON(count != 0);
		return false;
	}

	while (nnode) {
		node = nnode;
		nnode = rb_next(node);
		rb_erase(node, tree);
		count--;
		kfree(node);
	}
	BUG_ON(count != 0);
	BUG_ON(tree->rb_node != NULL);

	return true;
}

static int dust_clear_badblocks(struct dust_device *dd, char *result, unsigned int maxlen,
				unsigned int *sz_ptr)
{
	unsigned long flags;
	struct rb_root badblocklist;
	unsigned long long badblock_count;
	unsigned int sz = *sz_ptr;

	spin_lock_irqsave(&dd->dust_lock, flags);
	badblocklist = dd->badblocklist;
	badblock_count = dd->badblock_count;
	dd->badblocklist = RB_ROOT;
	dd->badblock_count = 0;
	spin_unlock_irqrestore(&dd->dust_lock, flags);

	if (!__dust_clear_badblocks(&badblocklist, badblock_count))
		DMEMIT("%s: no badblocks found", __func__);
	else
		DMEMIT("%s: badblocks cleared", __func__);

	return 1;
}

static int dust_list_badblocks(struct dust_device *dd, char *result, unsigned int maxlen,
				unsigned int *sz_ptr)
{
	unsigned long flags;
	struct rb_root badblocklist;
	struct rb_node *node;
	struct badblock *bblk;
	unsigned int sz = *sz_ptr;
	unsigned long long num = 0;

	spin_lock_irqsave(&dd->dust_lock, flags);
	badblocklist = dd->badblocklist;
	for (node = rb_first(&badblocklist); node; node = rb_next(node)) {
		bblk = rb_entry(node, struct badblock, node);
		DMEMIT("%llu\n", bblk->bb);
		num++;
	}

	spin_unlock_irqrestore(&dd->dust_lock, flags);
	if (!num)
		DMEMIT("No blocks in badblocklist");

	return 1;
}

/*
 * Target parameters:
 *
 * <device_path> <offset> <blksz>
 *
 * device_path: path to the block device
 * offset: offset to data area from start of device_path
 * blksz: block size (minimum 512, maximum 1073741824, must be a power of 2)
 */
static int dust_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct dust_device *dd;
	unsigned long long tmp;
	char dummy;
	unsigned int blksz;
	unsigned int sect_per_block;
	sector_t DUST_MAX_BLKSZ_SECTORS = 2097152;
	sector_t max_block_sectors = min(ti->len, DUST_MAX_BLKSZ_SECTORS);

	if (argc != 3) {
		ti->error = "Invalid argument count";
		return -EINVAL;
	}

	if (kstrtouint(argv[2], 10, &blksz) || !blksz) {
		ti->error = "Invalid block size parameter";
		return -EINVAL;
	}

	if (blksz < 512) {
		ti->error = "Block size must be at least 512";
		return -EINVAL;
	}

	if (!is_power_of_2(blksz)) {
		ti->error = "Block size must be a power of 2";
		return -EINVAL;
	}

	if (to_sector(blksz) > max_block_sectors) {
		ti->error = "Block size is too large";
		return -EINVAL;
	}

	sect_per_block = (blksz >> SECTOR_SHIFT);

	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
		ti->error = "Invalid device offset sector";
		return -EINVAL;
	}

	dd = kzalloc(sizeof(struct dust_device), GFP_KERNEL);
	if (dd == NULL) {
		ti->error = "Cannot allocate context";
		return -ENOMEM;
	}

	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dd->dev)) {
		ti->error = "Device lookup failed";
		kfree(dd);
		return -EINVAL;
	}

	dd->sect_per_block = sect_per_block;
	dd->blksz = blksz;
	dd->start = tmp;

	dd->sect_per_block_shift = __ffs(sect_per_block);

	/*
	 * Whether to fail a read on a "bad" block.
	 * Defaults to false; enabled later by message.
	 */
	dd->fail_read_on_bb = false;

	/*
	 * Initialize bad block list rbtree.
	 */
	dd->badblocklist = RB_ROOT;
	dd->badblock_count = 0;
	spin_lock_init(&dd->dust_lock);

	dd->quiet_mode = false;

	BUG_ON(dm_set_target_max_io_len(ti, dd->sect_per_block) != 0);

	ti->num_discard_bios = 1;
	ti->num_flush_bios = 1;
	ti->private = dd;

	return 0;
}

static void dust_dtr(struct dm_target *ti)
{
	struct dust_device *dd = ti->private;

	__dust_clear_badblocks(&dd->badblocklist, dd->badblock_count);
	dm_put_device(ti, dd->dev);
	kfree(dd);
}

static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
			char *result, unsigned int maxlen)
{
	struct dust_device *dd = ti->private;
	sector_t size = i_size_read(dd->dev->bdev->bd_inode) >> SECTOR_SHIFT;
	bool invalid_msg = false;
	int r = -EINVAL;
	unsigned long long tmp, block;
	unsigned char wr_fail_cnt;
	unsigned int tmp_ui;
	unsigned long flags;
	unsigned int sz = 0;
	char dummy;

	if (argc == 1) {
		if (!strcasecmp(argv[0], "addbadblock") ||
		    !strcasecmp(argv[0], "removebadblock") ||
		    !strcasecmp(argv[0], "queryblock")) {
			DMERR("%s requires an additional argument", argv[0]);
		} else if (!strcasecmp(argv[0], "disable")) {
			DMINFO("disabling read failures on bad sectors");
			dd->fail_read_on_bb = false;
			r = 0;
		} else if (!strcasecmp(argv[0], "enable")) {
			DMINFO("enabling read failures on bad sectors");
			dd->fail_read_on_bb = true;
			r = 0;
		} else if (!strcasecmp(argv[0], "countbadblocks")) {
			spin_lock_irqsave(&dd->dust_lock, flags);
			DMEMIT("countbadblocks: %llu badblock(s) found",
			       dd->badblock_count);
			spin_unlock_irqrestore(&dd->dust_lock, flags);
			r = 1;
		} else if (!strcasecmp(argv[0], "clearbadblocks")) {
			r = dust_clear_badblocks(dd, result, maxlen, &sz);
		} else if (!strcasecmp(argv[0], "quiet")) {
			if (!dd->quiet_mode)
				dd->quiet_mode = true;
			else
				dd->quiet_mode = false;
			r = 0;
		} else if (!strcasecmp(argv[0], "listbadblocks")) {
			r = dust_list_badblocks(dd, result, maxlen, &sz);
		} else {
			invalid_msg = true;
		}
	} else if (argc == 2) {
		if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
			return r;

		block = tmp;
		sector_div(size, dd->sect_per_block);
		if (block > size) {
			DMERR("selected block value out of range");
			return r;
		}

		if (!strcasecmp(argv[0], "addbadblock"))
			r = dust_add_block(dd, block, 0);
		else if (!strcasecmp(argv[0], "removebadblock"))
			r = dust_remove_block(dd, block);
		else if (!strcasecmp(argv[0], "queryblock"))
			r = dust_query_block(dd, block, result, maxlen, &sz);
		else
			invalid_msg = true;

	} else if (argc == 3) {
		if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
			return r;

		if (sscanf(argv[2], "%u%c", &tmp_ui, &dummy) != 1)
			return r;

		block = tmp;
		if (tmp_ui > 255) {
			DMERR("selected write fail count out of range");
			return r;
		}
		wr_fail_cnt = tmp_ui;
		sector_div(size, dd->sect_per_block);
		if (block > size) {
			DMERR("selected block value out of range");
			return r;
		}

		if (!strcasecmp(argv[0], "addbadblock"))
			r = dust_add_block(dd, block, wr_fail_cnt);
		else
			invalid_msg = true;

	} else
		DMERR("invalid number of arguments '%d'", argc);

	if (invalid_msg)
		DMERR("unrecognized message '%s' received", argv[0]);

	return r;
}

static void dust_status(struct dm_target *ti, status_type_t type,
			unsigned int status_flags, char *result, unsigned int maxlen)
{
	struct dust_device *dd = ti->private;
	unsigned int sz = 0;

	switch (type) {
	case STATUSTYPE_INFO:
		DMEMIT("%s %s %s", dd->dev->name,
		       dd->fail_read_on_bb ? "fail_read_on_bad_block" : "bypass",
		       dd->quiet_mode ? "quiet" : "verbose");
		break;

	case STATUSTYPE_TABLE:
		DMEMIT("%s %llu %u", dd->dev->name,
		       (unsigned long long)dd->start, dd->blksz);
		break;
	}
}

static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
{
	struct dust_device *dd = ti->private;
	struct dm_dev *dev = dd->dev;

	*bdev = dev->bdev;

	/*
	 * Only pass ioctls through if the device sizes match exactly.
	 */
	if (dd->start ||
	    ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
		return 1;

	return 0;
}

static int dust_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn,
				void *data)
{
	struct dust_device *dd = ti->private;

	return fn(ti, dd->dev, dd->start, ti->len, data);
}

static struct target_type dust_target = {
	.name = "dust",
	.version = {1, 0, 0},
	.module = THIS_MODULE,
	.ctr = dust_ctr,
	.dtr = dust_dtr,
	.iterate_devices = dust_iterate_devices,
	.map = dust_map,
	.message = dust_message,
	.status = dust_status,
	.prepare_ioctl = dust_prepare_ioctl,
};

static int __init dm_dust_init(void)
{
	int r = dm_register_target(&dust_target);

	if (r < 0)
		DMERR("dm_register_target failed %d", r);

	return r;
}

static void __exit dm_dust_exit(void)
{
	dm_unregister_target(&dust_target);
}

module_init(dm_dust_init);
module_exit(dm_dust_exit);

MODULE_DESCRIPTION(DM_NAME " dust test target");
MODULE_AUTHOR("Bryan Gurney <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");