drivers/md/persistent-data/dm-space-map-checker.c

   1 /*
   2  * Copyright (C) 2011 Red Hat, Inc.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-space-map-checker.h"
   8
   9 #include <linux/device-mapper.h>
  10
  11 #ifdef CONFIG_DM_DEBUG_SPACE_MAPS
  12
  13 #define DM_MSG_PREFIX "space map checker"
  14
  15 /*----------------------------------------------------------------*/
  16
  17 struct count_array {
  18         dm_block_t nr;
  19         dm_block_t nr_free;
  20
  21         uint32_t *counts;
  22 };
  23
  24 static int ca_get_count(struct count_array *ca, dm_block_t b, uint32_t *count)
  25 {
  26         if (b >= ca->nr)
  27                 return -EINVAL;
  28
  29         *count = ca->counts[b];
  30         return 0;
  31 }
  32
  33 static int ca_count_more_than_one(struct count_array *ca, dm_block_t b, int *r)
  34 {
  35         if (b >= ca->nr)
  36                 return -EINVAL;
  37
  38         *r = ca->counts[b] > 1;
  39         return 0;
  40 }
  41
  42 static int ca_set_count(struct count_array *ca, dm_block_t b, uint32_t count)
  43 {
  44         uint32_t old_count;
  45
  46         if (b >= ca->nr)
  47                 return -EINVAL;
  48
  49         old_count = ca->counts[b];
  50
  51         if (!count && old_count)
  52                 ca->nr_free++;
  53
  54         else if (count && !old_count)
  55                 ca->nr_free--;
  56
  57         ca->counts[b] = count;
  58         return 0;
  59 }
  60
  61 static int ca_inc_block(struct count_array *ca, dm_block_t b)
  62 {
  63         if (b >= ca->nr)
  64                 return -EINVAL;
  65
  66         ca_set_count(ca, b, ca->counts[b] + 1);
  67         return 0;
  68 }
  69
  70 static int ca_dec_block(struct count_array *ca, dm_block_t b)
  71 {
  72         if (b >= ca->nr)
  73                 return -EINVAL;
  74
  75         BUG_ON(ca->counts[b] == 0);
  76         ca_set_count(ca, b, ca->counts[b] - 1);
  77         return 0;
  78 }
  79
  80 static int ca_create(struct count_array *ca, struct dm_space_map *sm)
  81 {
  82         int r;
  83         dm_block_t nr_blocks;
  84
  85         r = dm_sm_get_nr_blocks(sm, &nr_blocks);
  86         if (r)
  87                 return r;
  88
  89         ca->nr = nr_blocks;
  90         ca->nr_free = nr_blocks;
  91         ca->counts = kzalloc(sizeof(*ca->counts) * nr_blocks, GFP_KERNEL);
  92         if (!ca->counts)
  93                 return -ENOMEM;
  94
  95         return 0;
  96 }
  97
  98 static int ca_load(struct count_array *ca, struct dm_space_map *sm)
  99 {
 100         int r;
 101         uint32_t count;
 102         dm_block_t nr_blocks, i;
 103
 104         r = dm_sm_get_nr_blocks(sm, &nr_blocks);
 105         if (r)
 106                 return r;
 107
 108         BUG_ON(ca->nr != nr_blocks);
 109
 110         DMWARN("Loading debug space map from disk.  This may take some time");
 111         for (i = 0; i < nr_blocks; i++) {
 112                 r = dm_sm_get_count(sm, i, &count);
 113                 if (r) {
 114                         DMERR("load failed");
 115                         return r;
 116                 }
 117
 118                 ca_set_count(ca, i, count);
 119         }
 120         DMWARN("Load complete");
 121
 122         return 0;
 123 }
 124
 125 static int ca_extend(struct count_array *ca, dm_block_t extra_blocks)
 126 {
 127         dm_block_t nr_blocks = ca->nr + extra_blocks;
 128         uint32_t *counts = kzalloc(sizeof(*counts) * nr_blocks, GFP_KERNEL);
 129         if (!counts)
 130                 return -ENOMEM;
 131
 132         memcpy(counts, ca->counts, sizeof(*counts) * ca->nr);
 133         kfree(ca->counts);
 134         ca->nr = nr_blocks;
 135         ca->nr_free += extra_blocks;
 136         ca->counts = counts;
 137         return 0;
 138 }
 139
 140 static int ca_commit(struct count_array *old, struct count_array *new)
 141 {
 142         if (old->nr != new->nr) {
 143                 BUG_ON(old->nr > new->nr);
 144                 ca_extend(old, new->nr - old->nr);
 145         }
 146
 147         BUG_ON(old->nr != new->nr);
 148         old->nr_free = new->nr_free;
 149         memcpy(old->counts, new->counts, sizeof(*old->counts) * old->nr);
 150         return 0;
 151 }
 152
 153 static void ca_destroy(struct count_array *ca)
 154 {
 155         kfree(ca->counts);
 156 }
 157
 158 /*----------------------------------------------------------------*/
 159
 160 struct sm_checker {
 161         struct dm_space_map sm;
 162
 163         struct count_array old_counts;
 164         struct count_array counts;
 165
 166         struct dm_space_map *real_sm;
 167 };
 168
 169 static void sm_checker_destroy(struct dm_space_map *sm)
 170 {
 171         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 172
 173         dm_sm_destroy(smc->real_sm);
 174         ca_destroy(&smc->old_counts);
 175         ca_destroy(&smc->counts);
 176         kfree(smc);
 177 }
 178
 179 static int sm_checker_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 180 {
 181         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 182         int r = dm_sm_get_nr_blocks(smc->real_sm, count);
 183         if (!r)
 184                 BUG_ON(smc->old_counts.nr != *count);
 185         return r;
 186 }
 187
 188 static int sm_checker_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 189 {
 190         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 191         int r = dm_sm_get_nr_free(smc->real_sm, count);
 192         if (!r) {
 193                 /*
 194                  * Slow, but we know it's correct.
 195                  */
 196                 dm_block_t b, n = 0;
 197                 for (b = 0; b < smc->old_counts.nr; b++)
 198                         if (smc->old_counts.counts[b] == 0 &&
 199                             smc->counts.counts[b] == 0)
 200                                 n++;
 201
 202                 if (n != *count)
 203                         DMERR("free block counts differ, checker %u, sm-disk:%u",
 204                               (unsigned) n, (unsigned) *count);
 205         }
 206         return r;
 207 }
 208
 209 static int sm_checker_new_block(struct dm_space_map *sm, dm_block_t *b)
 210 {
 211         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 212         int r = dm_sm_new_block(smc->real_sm, b);
 213
 214         if (!r) {
 215                 BUG_ON(*b >= smc->old_counts.nr);
 216                 BUG_ON(smc->old_counts.counts[*b] != 0);
 217                 BUG_ON(*b >= smc->counts.nr);
 218                 BUG_ON(smc->counts.counts[*b] != 0);
 219                 ca_set_count(&smc->counts, *b, 1);
 220         }
 221
 222         return r;
 223 }
 224
 225 static int sm_checker_inc_block(struct dm_space_map *sm, dm_block_t b)
 226 {
 227         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 228         int r = dm_sm_inc_block(smc->real_sm, b);
 229         int r2 = ca_inc_block(&smc->counts, b);
 230         BUG_ON(r != r2);
 231         return r;
 232 }
 233
 234 static int sm_checker_dec_block(struct dm_space_map *sm, dm_block_t b)
 235 {
 236         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 237         int r = dm_sm_dec_block(smc->real_sm, b);
 238         int r2 = ca_dec_block(&smc->counts, b);
 239         BUG_ON(r != r2);
 240         return r;
 241 }
 242
 243 static int sm_checker_get_count(struct dm_space_map *sm, dm_block_t b, uint32_t *result)
 244 {
 245         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 246         uint32_t result2 = 0;
 247         int r = dm_sm_get_count(smc->real_sm, b, result);
 248         int r2 = ca_get_count(&smc->counts, b, &result2);
 249
 250         BUG_ON(r != r2);
 251         if (!r)
 252                 BUG_ON(*result != result2);
 253         return r;
 254 }
 255
 256 static int sm_checker_count_more_than_one(struct dm_space_map *sm, dm_block_t b, int *result)
 257 {
 258         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 259         int result2 = 0;
 260         int r = dm_sm_count_is_more_than_one(smc->real_sm, b, result);
 261         int r2 = ca_count_more_than_one(&smc->counts, b, &result2);
 262
 263         BUG_ON(r != r2);
 264         if (!r)
 265                 BUG_ON(!(*result) && result2);
 266         return r;
 267 }
 268
 269 static int sm_checker_set_count(struct dm_space_map *sm, dm_block_t b, uint32_t count)
 270 {
 271         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 272         uint32_t old_rc;
 273         int r = dm_sm_set_count(smc->real_sm, b, count);
 274         int r2;
 275
 276         BUG_ON(b >= smc->counts.nr);
 277         old_rc = smc->counts.counts[b];
 278         r2 = ca_set_count(&smc->counts, b, count);
 279         BUG_ON(r != r2);
 280
 281         return r;
 282 }
 283
 284 static int sm_checker_commit(struct dm_space_map *sm)
 285 {
 286         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 287         int r;
 288
 289         r = dm_sm_commit(smc->real_sm);
 290         if (r)
 291                 return r;
 292
 293         r = ca_commit(&smc->old_counts, &smc->counts);
 294         if (r)
 295                 return r;
 296
 297         return 0;
 298 }
 299
 300 static int sm_checker_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 301 {
 302         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 303         int r = dm_sm_extend(smc->real_sm, extra_blocks);
 304         if (r)
 305                 return r;
 306
 307         return ca_extend(&smc->counts, extra_blocks);
 308 }
 309
 310 static int sm_checker_root_size(struct dm_space_map *sm, size_t *result)
 311 {
 312         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 313         return dm_sm_root_size(smc->real_sm, result);
 314 }
 315
 316 static int sm_checker_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
 317 {
 318         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 319         return dm_sm_copy_root(smc->real_sm, copy_to_here_le, len);
 320 }
 321
 322 /*----------------------------------------------------------------*/
 323
 324 static struct dm_space_map ops_ = {
 325         .destroy = sm_checker_destroy,
 326         .get_nr_blocks = sm_checker_get_nr_blocks,
 327         .get_nr_free = sm_checker_get_nr_free,
 328         .inc_block = sm_checker_inc_block,
 329         .dec_block = sm_checker_dec_block,
 330         .new_block = sm_checker_new_block,
 331         .get_count = sm_checker_get_count,
 332         .count_is_more_than_one = sm_checker_count_more_than_one,
 333         .set_count = sm_checker_set_count,
 334         .commit = sm_checker_commit,
 335         .extend = sm_checker_extend,
 336         .root_size = sm_checker_root_size,
 337         .copy_root = sm_checker_copy_root
 338 };
 339
 340 struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
 341 {
 342         int r;
 343         struct sm_checker *smc;
 344
 345         if (!sm)
 346                 return NULL;
 347
 348         smc = kmalloc(sizeof(*smc), GFP_KERNEL);
 349         if (!smc)
 350                 return NULL;
 351
 352         memcpy(&smc->sm, &ops_, sizeof(smc->sm));
 353         r = ca_create(&smc->old_counts, sm);
 354         if (r) {
 355                 kfree(smc);
 356                 return NULL;
 357         }
 358
 359         r = ca_create(&smc->counts, sm);
 360         if (r) {
 361                 ca_destroy(&smc->old_counts);
 362                 kfree(smc);
 363                 return NULL;
 364         }
 365
 366         smc->real_sm = sm;
 367
 368         r = ca_load(&smc->counts, sm);
 369         if (r) {
 370                 ca_destroy(&smc->counts);
 371                 ca_destroy(&smc->old_counts);
 372                 kfree(smc);
 373                 return NULL;
 374         }
 375
 376         r = ca_commit(&smc->old_counts, &smc->counts);
 377         if (r) {
 378                 ca_destroy(&smc->counts);
 379                 ca_destroy(&smc->old_counts);
 380                 kfree(smc);
 381                 return NULL;
 382         }
 383
 384         return &smc->sm;
 385 }
 386 EXPORT_SYMBOL_GPL(dm_sm_checker_create);
 387
 388 struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
 389 {
 390         int r;
 391         struct sm_checker *smc;
 392
 393         if (!sm)
 394                 return NULL;
 395
 396         smc = kmalloc(sizeof(*smc), GFP_KERNEL);
 397         if (!smc)
 398                 return NULL;
 399
 400         memcpy(&smc->sm, &ops_, sizeof(smc->sm));
 401         r = ca_create(&smc->old_counts, sm);
 402         if (r) {
 403                 kfree(smc);
 404                 return NULL;
 405         }
 406
 407         r = ca_create(&smc->counts, sm);
 408         if (r) {
 409                 ca_destroy(&smc->old_counts);
 410                 kfree(smc);
 411                 return NULL;
 412         }
 413
 414         smc->real_sm = sm;
 415         return &smc->sm;
 416 }
 417 EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);
 418
 419 /*----------------------------------------------------------------*/
 420
 421 #else
 422
 423 struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
 424 {
 425         return sm;
 426 }
 427 EXPORT_SYMBOL_GPL(dm_sm_checker_create);
 428
 429 struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
 430 {
 431         return sm;
 432 }
 433 EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);
 434
 435 /*----------------------------------------------------------------*/
 436
 437 #endif