summaryrefslogtreecommitdiffstats
path: root/drivers/md/persistent-data/dm-space-map-checker.c
blob: bb44a937fe635b1f38641ef771b3bd81ce8306d8 (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
/*
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#include "dm-space-map-checker.h"

#include <linux/device-mapper.h>

#ifdef CONFIG_DM_DEBUG_SPACE_MAPS

#define DM_MSG_PREFIX "space map checker"

/*----------------------------------------------------------------*/

struct count_array {
	dm_block_t nr;
	dm_block_t nr_free;

	uint32_t *counts;
};

static int ca_get_count(struct count_array *ca, dm_block_t b, uint32_t *count)
{
	if (b >= ca->nr)
		return -EINVAL;

	*count = ca->counts[b];
	return 0;
}

static int ca_count_more_than_one(struct count_array *ca, dm_block_t b, int *r)
{
	if (b >= ca->nr)
		return -EINVAL;

	*r = ca->counts[b] > 1;
	return 0;
}

static int ca_set_count(struct count_array *ca, dm_block_t b, uint32_t count)
{
	uint32_t old_count;

	if (b >= ca->nr)
		return -EINVAL;

	old_count = ca->counts[b];

	if (!count && old_count)
		ca->nr_free++;

	else if (count && !old_count)
		ca->nr_free--;

	ca->counts[b] = count;
	return 0;
}

static int ca_inc_block(struct count_array *ca, dm_block_t b)
{
	if (b >= ca->nr)
		return -EINVAL;

	ca_set_count(ca, b, ca->counts[b] + 1);
	return 0;
}

static int ca_dec_block(struct count_array *ca, dm_block_t b)
{
	if (b >= ca->nr)
		return -EINVAL;

	BUG_ON(ca->counts[b] == 0);
	ca_set_count(ca, b, ca->counts[b] - 1);
	return 0;
}

static int ca_create(struct count_array *ca, struct dm_space_map *sm)
{
	int r;
	dm_block_t nr_blocks;

	r = dm_sm_get_nr_blocks(sm, &nr_blocks);
	if (r)
		return r;

	ca->nr = nr_blocks;
	ca->nr_free = nr_blocks;
	ca->counts = kzalloc(sizeof(*ca->counts) * nr_blocks, GFP_KERNEL);
	if (!ca->counts)
		return -ENOMEM;

	return 0;
}

static int ca_load(struct count_array *ca, struct dm_space_map *sm)
{
	int r;
	uint32_t count;
	dm_block_t nr_blocks, i;

	r = dm_sm_get_nr_blocks(sm, &nr_blocks);
	if (r)
		return r;

	BUG_ON(ca->nr != nr_blocks);

	DMWARN("Loading debug space map from disk.  This may take some time");
	for (i = 0; i < nr_blocks; i++) {
		r = dm_sm_get_count(sm, i, &count);
		if (r) {
			DMERR("load failed");
			return r;
		}

		ca_set_count(ca, i, count);
	}
	DMWARN("Load complete");

	return 0;
}

static int ca_extend(struct count_array *ca, dm_block_t extra_blocks)
{
	dm_block_t nr_blocks = ca->nr + extra_blocks;
	uint32_t *counts = kzalloc(sizeof(*counts) * nr_blocks, GFP_KERNEL);
	if (!counts)
		return -ENOMEM;

	memcpy(counts, ca->counts, sizeof(*counts) * ca->nr);
	kfree(ca->counts);
	ca->nr = nr_blocks;
	ca->nr_free += extra_blocks;
	ca->counts = counts;
	return 0;
}

static int ca_commit(struct count_array *old, struct count_array *new)
{
	if (old->nr != new->nr) {
		BUG_ON(old->nr > new->nr);
		ca_extend(old, new->nr - old->nr);
	}

	BUG_ON(old->nr != new->nr);
	old->nr_free = new->nr_free;
	memcpy(old->counts, new->counts, sizeof(*old->counts) * old->nr);
	return 0;
}

static void ca_destroy(struct count_array *ca)
{
	kfree(ca->counts);
}

/*----------------------------------------------------------------*/

struct sm_checker {
	struct dm_space_map sm;

	struct count_array old_counts;
	struct count_array counts;

	struct dm_space_map *real_sm;
};

static void sm_checker_destroy(struct dm_space_map *sm)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);

	dm_sm_destroy(smc->real_sm);
	ca_destroy(&smc->old_counts);
	ca_destroy(&smc->counts);
	kfree(smc);
}

static int sm_checker_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r = dm_sm_get_nr_blocks(smc->real_sm, count);
	if (!r)
		BUG_ON(smc->old_counts.nr != *count);
	return r;
}

static int sm_checker_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r = dm_sm_get_nr_free(smc->real_sm, count);
	if (!r) {
		/*
		 * Slow, but we know it's correct.
		 */
		dm_block_t b, n = 0;
		for (b = 0; b < smc->old_counts.nr; b++)
			if (smc->old_counts.counts[b] == 0 &&
			    smc->counts.counts[b] == 0)
				n++;

		if (n != *count)
			DMERR("free block counts differ, checker %u, sm-disk:%u",
			      (unsigned) n, (unsigned) *count);
	}
	return r;
}

static int sm_checker_new_block(struct dm_space_map *sm, dm_block_t *b)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r = dm_sm_new_block(smc->real_sm, b);

	if (!r) {
		BUG_ON(*b >= smc->old_counts.nr);
		BUG_ON(smc->old_counts.counts[*b] != 0);
		BUG_ON(*b >= smc->counts.nr);
		BUG_ON(smc->counts.counts[*b] != 0);
		ca_set_count(&smc->counts, *b, 1);
	}

	return r;
}

static int sm_checker_inc_block(struct dm_space_map *sm, dm_block_t b)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r = dm_sm_inc_block(smc->real_sm, b);
	int r2 = ca_inc_block(&smc->counts, b);
	BUG_ON(r != r2);
	return r;
}

static int sm_checker_dec_block(struct dm_space_map *sm, dm_block_t b)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r = dm_sm_dec_block(smc->real_sm, b);
	int r2 = ca_dec_block(&smc->counts, b);
	BUG_ON(r != r2);
	return r;
}

static int sm_checker_get_count(struct dm_space_map *sm, dm_block_t b, uint32_t *result)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	uint32_t result2 = 0;
	int r = dm_sm_get_count(smc->real_sm, b, result);
	int r2 = ca_get_count(&smc->counts, b, &result2);

	BUG_ON(r != r2);
	if (!r)
		BUG_ON(*result != result2);
	return r;
}

static int sm_checker_count_more_than_one(struct dm_space_map *sm, dm_block_t b, int *result)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int result2 = 0;
	int r = dm_sm_count_is_more_than_one(smc->real_sm, b, result);
	int r2 = ca_count_more_than_one(&smc->counts, b, &result2);

	BUG_ON(r != r2);
	if (!r)
		BUG_ON(!(*result) && result2);
	return r;
}

static int sm_checker_set_count(struct dm_space_map *sm, dm_block_t b, uint32_t count)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	uint32_t old_rc;
	int r = dm_sm_set_count(smc->real_sm, b, count);
	int r2;

	BUG_ON(b >= smc->counts.nr);
	old_rc = smc->counts.counts[b];
	r2 = ca_set_count(&smc->counts, b, count);
	BUG_ON(r != r2);

	return r;
}

static int sm_checker_commit(struct dm_space_map *sm)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r;

	r = dm_sm_commit(smc->real_sm);
	if (r)
		return r;

	r = ca_commit(&smc->old_counts, &smc->counts);
	if (r)
		return r;

	return 0;
}

static int sm_checker_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	int r = dm_sm_extend(smc->real_sm, extra_blocks);
	if (r)
		return r;

	return ca_extend(&smc->counts, extra_blocks);
}

static int sm_checker_root_size(struct dm_space_map *sm, size_t *result)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	return dm_sm_root_size(smc->real_sm, result);
}

static int sm_checker_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
{
	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
	return dm_sm_copy_root(smc->real_sm, copy_to_here_le, len);
}

/*----------------------------------------------------------------*/

static struct dm_space_map ops_ = {
	.destroy = sm_checker_destroy,
	.get_nr_blocks = sm_checker_get_nr_blocks,
	.get_nr_free = sm_checker_get_nr_free,
	.inc_block = sm_checker_inc_block,
	.dec_block = sm_checker_dec_block,
	.new_block = sm_checker_new_block,
	.get_count = sm_checker_get_count,
	.count_is_more_than_one = sm_checker_count_more_than_one,
	.set_count = sm_checker_set_count,
	.commit = sm_checker_commit,
	.extend = sm_checker_extend,
	.root_size = sm_checker_root_size,
	.copy_root = sm_checker_copy_root
};

struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
{
	int r;
	struct sm_checker *smc;

	if (!sm)
		return NULL;

	smc = kmalloc(sizeof(*smc), GFP_KERNEL);
	if (!smc)
		return NULL;

	memcpy(&smc->sm, &ops_, sizeof(smc->sm));
	r = ca_create(&smc->old_counts, sm);
	if (r) {
		kfree(smc);
		return NULL;
	}

	r = ca_create(&smc->counts, sm);
	if (r) {
		ca_destroy(&smc->old_counts);
		kfree(smc);
		return NULL;
	}

	smc->real_sm = sm;

	r = ca_load(&smc->counts, sm);
	if (r) {
		ca_destroy(&smc->counts);
		ca_destroy(&smc->old_counts);
		kfree(smc);
		return NULL;
	}

	r = ca_commit(&smc->old_counts, &smc->counts);
	if (r) {
		ca_destroy(&smc->counts);
		ca_destroy(&smc->old_counts);
		kfree(smc);
		return NULL;
	}

	return &smc->sm;
}
EXPORT_SYMBOL_GPL(dm_sm_checker_create);

struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
{
	int r;
	struct sm_checker *smc;

	if (!sm)
		return NULL;

	smc = kmalloc(sizeof(*smc), GFP_KERNEL);
	if (!smc)
		return NULL;

	memcpy(&smc->sm, &ops_, sizeof(smc->sm));
	r = ca_create(&smc->old_counts, sm);
	if (r) {
		kfree(smc);
		return NULL;
	}

	r = ca_create(&smc->counts, sm);
	if (r) {
		ca_destroy(&smc->old_counts);
		kfree(smc);
		return NULL;
	}

	smc->real_sm = sm;
	return &smc->sm;
}
EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);

/*----------------------------------------------------------------*/

#else

struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
{
	return sm;
}
EXPORT_SYMBOL_GPL(dm_sm_checker_create);

struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
{
	return sm;
}
EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);

/*----------------------------------------------------------------*/

#endif