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 #include <linux/export.h>
  11 #include <linux/vmalloc.h>
  12
  13 #ifdef CONFIG_DM_DEBUG_SPACE_MAPS
  14
  15 #define DM_MSG_PREFIX "space map checker"
  16
  17 /*----------------------------------------------------------------*/
  18
  19 struct count_array {
  20         dm_block_t nr;
  21         dm_block_t nr_free;
  22
  23         uint32_t *counts;
  24 };
  25
  26 static int ca_get_count(struct count_array *ca, dm_block_t b, uint32_t *count)
  27 {
  28         if (b >= ca->nr)
  29                 return -EINVAL;
  30
  31         *count = ca->counts[b];
  32         return 0;
  33 }
  34
  35 static int ca_count_more_than_one(struct count_array *ca, dm_block_t b, int *r)
  36 {
  37         if (b >= ca->nr)
  38                 return -EINVAL;
  39
  40         *r = ca->counts[b] > 1;
  41         return 0;
  42 }
  43
  44 static int ca_set_count(struct count_array *ca, dm_block_t b, uint32_t count)
  45 {
  46         uint32_t old_count;
  47
  48         if (b >= ca->nr)
  49                 return -EINVAL;
  50
  51         old_count = ca->counts[b];
  52
  53         if (!count && old_count)
  54                 ca->nr_free++;
  55
  56         else if (count && !old_count)
  57                 ca->nr_free--;
  58
  59         ca->counts[b] = count;
  60         return 0;
  61 }
  62
  63 static int ca_inc_block(struct count_array *ca, dm_block_t b)
  64 {
  65         if (b >= ca->nr)
  66                 return -EINVAL;
  67
  68         ca_set_count(ca, b, ca->counts[b] + 1);
  69         return 0;
  70 }
  71
  72 static int ca_dec_block(struct count_array *ca, dm_block_t b)
  73 {
  74         if (b >= ca->nr)
  75                 return -EINVAL;
  76
  77         BUG_ON(ca->counts[b] == 0);
  78         ca_set_count(ca, b, ca->counts[b] - 1);
  79         return 0;
  80 }
  81
  82 static int ca_create(struct count_array *ca, struct dm_space_map *sm)
  83 {
  84         int r;
  85         dm_block_t nr_blocks;
  86
  87         r = dm_sm_get_nr_blocks(sm, &nr_blocks);
  88         if (r)
  89                 return r;
  90
  91         ca->nr = nr_blocks;
  92         ca->nr_free = nr_blocks;
  93
  94         if (!nr_blocks)
  95                 ca->counts = NULL;
  96         else {
  97                 ca->counts = vzalloc(sizeof(*ca->counts) * nr_blocks);
  98                 if (!ca->counts)
  99                         return -ENOMEM;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static void ca_destroy(struct count_array *ca)
 106 {
 107         vfree(ca->counts);
 108 }
 109
 110 static int ca_load(struct count_array *ca, struct dm_space_map *sm)
 111 {
 112         int r;
 113         uint32_t count;
 114         dm_block_t nr_blocks, i;
 115
 116         r = dm_sm_get_nr_blocks(sm, &nr_blocks);
 117         if (r)
 118                 return r;
 119
 120         BUG_ON(ca->nr != nr_blocks);
 121
 122         DMWARN("Loading debug space map from disk.  This may take some time");
 123         for (i = 0; i < nr_blocks; i++) {
 124                 r = dm_sm_get_count(sm, i, &count);
 125                 if (r) {
 126                         DMERR("load failed");
 127                         return r;
 128                 }
 129
 130                 ca_set_count(ca, i, count);
 131         }
 132         DMWARN("Load complete");
 133
 134         return 0;
 135 }
 136
 137 static int ca_extend(struct count_array *ca, dm_block_t extra_blocks)
 138 {
 139         dm_block_t nr_blocks = ca->nr + extra_blocks;
 140         uint32_t *counts = vzalloc(sizeof(*counts) * nr_blocks);
 141         if (!counts)
 142                 return -ENOMEM;
 143
 144         if (ca->counts) {
 145                 memcpy(counts, ca->counts, sizeof(*counts) * ca->nr);
 146                 ca_destroy(ca);
 147         }
 148         ca->nr = nr_blocks;
 149         ca->nr_free += extra_blocks;
 150         ca->counts = counts;
 151         return 0;
 152 }
 153
 154 static int ca_commit(struct count_array *old, struct count_array *new)
 155 {
 156         if (old->nr != new->nr) {
 157                 BUG_ON(old->nr > new->nr);
 158                 ca_extend(old, new->nr - old->nr);
 159         }
 160
 161         BUG_ON(old->nr != new->nr);
 162         old->nr_free = new->nr_free;
 163         memcpy(old->counts, new->counts, sizeof(*old->counts) * old->nr);
 164         return 0;
 165 }
 166
 167 /*----------------------------------------------------------------*/
 168
 169 struct sm_checker {
 170         struct dm_space_map sm;
 171
 172         struct count_array old_counts;
 173         struct count_array counts;
 174
 175         struct dm_space_map *real_sm;
 176 };
 177
 178 static void sm_checker_destroy(struct dm_space_map *sm)
 179 {
 180         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 181
 182         dm_sm_destroy(smc->real_sm);
 183         ca_destroy(&smc->old_counts);
 184         ca_destroy(&smc->counts);
 185         kfree(smc);
 186 }
 187
 188 static int sm_checker_get_nr_blocks(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_blocks(smc->real_sm, count);
 192         if (!r)
 193                 BUG_ON(smc->old_counts.nr != *count);
 194         return r;
 195 }
 196
 197 static int sm_checker_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 198 {
 199         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 200         int r = dm_sm_get_nr_free(smc->real_sm, count);
 201         if (!r) {
 202                 /*
 203                  * Slow, but we know it's correct.
 204                  */
 205                 dm_block_t b, n = 0;
 206                 for (b = 0; b < smc->old_counts.nr; b++)
 207                         if (smc->old_counts.counts[b] == 0 &&
 208                             smc->counts.counts[b] == 0)
 209                                 n++;
 210
 211                 if (n != *count)
 212                         DMERR("free block counts differ, checker %u, sm-disk:%u",
 213                               (unsigned) n, (unsigned) *count);
 214         }
 215         return r;
 216 }
 217
 218 static int sm_checker_new_block(struct dm_space_map *sm, dm_block_t *b)
 219 {
 220         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 221         int r = dm_sm_new_block(smc->real_sm, b);
 222
 223         if (!r) {
 224                 BUG_ON(*b >= smc->old_counts.nr);
 225                 BUG_ON(smc->old_counts.counts[*b] != 0);
 226                 BUG_ON(*b >= smc->counts.nr);
 227                 BUG_ON(smc->counts.counts[*b] != 0);
 228                 ca_set_count(&smc->counts, *b, 1);
 229         }
 230
 231         return r;
 232 }
 233
 234 static int sm_checker_inc_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_inc_block(smc->real_sm, b);
 238         int r2 = ca_inc_block(&smc->counts, b);
 239         BUG_ON(r != r2);
 240         return r;
 241 }
 242
 243 static int sm_checker_dec_block(struct dm_space_map *sm, dm_block_t b)
 244 {
 245         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 246         int r = dm_sm_dec_block(smc->real_sm, b);
 247         int r2 = ca_dec_block(&smc->counts, b);
 248         BUG_ON(r != r2);
 249         return r;
 250 }
 251
 252 static int sm_checker_get_count(struct dm_space_map *sm, dm_block_t b, uint32_t *result)
 253 {
 254         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 255         uint32_t result2 = 0;
 256         int r = dm_sm_get_count(smc->real_sm, b, result);
 257         int r2 = ca_get_count(&smc->counts, b, &result2);
 258
 259         BUG_ON(r != r2);
 260         if (!r)
 261                 BUG_ON(*result != result2);
 262         return r;
 263 }
 264
 265 static int sm_checker_count_more_than_one(struct dm_space_map *sm, dm_block_t b, int *result)
 266 {
 267         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 268         int result2 = 0;
 269         int r = dm_sm_count_is_more_than_one(smc->real_sm, b, result);
 270         int r2 = ca_count_more_than_one(&smc->counts, b, &result2);
 271
 272         BUG_ON(r != r2);
 273         if (!r)
 274                 BUG_ON(!(*result) && result2);
 275         return r;
 276 }
 277
 278 static int sm_checker_set_count(struct dm_space_map *sm, dm_block_t b, uint32_t count)
 279 {
 280         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 281         uint32_t old_rc;
 282         int r = dm_sm_set_count(smc->real_sm, b, count);
 283         int r2;
 284
 285         BUG_ON(b >= smc->counts.nr);
 286         old_rc = smc->counts.counts[b];
 287         r2 = ca_set_count(&smc->counts, b, count);
 288         BUG_ON(r != r2);
 289
 290         return r;
 291 }
 292
 293 static int sm_checker_commit(struct dm_space_map *sm)
 294 {
 295         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 296         int r;
 297
 298         r = dm_sm_commit(smc->real_sm);
 299         if (r)
 300                 return r;
 301
 302         r = ca_commit(&smc->old_counts, &smc->counts);
 303         if (r)
 304                 return r;
 305
 306         return 0;
 307 }
 308
 309 static int sm_checker_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 310 {
 311         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 312         int r = dm_sm_extend(smc->real_sm, extra_blocks);
 313         if (r)
 314                 return r;
 315
 316         return ca_extend(&smc->counts, extra_blocks);
 317 }
 318
 319 static int sm_checker_root_size(struct dm_space_map *sm, size_t *result)
 320 {
 321         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 322         return dm_sm_root_size(smc->real_sm, result);
 323 }
 324
 325 static int sm_checker_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
 326 {
 327         struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
 328         return dm_sm_copy_root(smc->real_sm, copy_to_here_le, len);
 329 }
 330
 331 /*----------------------------------------------------------------*/
 332
 333 static struct dm_space_map ops_ = {
 334         .destroy = sm_checker_destroy,
 335         .get_nr_blocks = sm_checker_get_nr_blocks,
 336         .get_nr_free = sm_checker_get_nr_free,
 337         .inc_block = sm_checker_inc_block,
 338         .dec_block = sm_checker_dec_block,
 339         .new_block = sm_checker_new_block,
 340         .get_count = sm_checker_get_count,
 341         .count_is_more_than_one = sm_checker_count_more_than_one,
 342         .set_count = sm_checker_set_count,
 343         .commit = sm_checker_commit,
 344         .extend = sm_checker_extend,
 345         .root_size = sm_checker_root_size,
 346         .copy_root = sm_checker_copy_root
 347 };
 348
 349 struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
 350 {
 351         int r;
 352         struct sm_checker *smc;
 353
 354         if (IS_ERR_OR_NULL(sm))
 355                 return ERR_PTR(-EINVAL);
 356
 357         smc = kmalloc(sizeof(*smc), GFP_KERNEL);
 358         if (!smc)
 359                 return ERR_PTR(-ENOMEM);
 360
 361         memcpy(&smc->sm, &ops_, sizeof(smc->sm));
 362         r = ca_create(&smc->old_counts, sm);
 363         if (r) {
 364                 kfree(smc);
 365                 return ERR_PTR(r);
 366         }
 367
 368         r = ca_create(&smc->counts, sm);
 369         if (r) {
 370                 ca_destroy(&smc->old_counts);
 371                 kfree(smc);
 372                 return ERR_PTR(r);
 373         }
 374
 375         smc->real_sm = sm;
 376
 377         r = ca_load(&smc->counts, sm);
 378         if (r) {
 379                 ca_destroy(&smc->counts);
 380                 ca_destroy(&smc->old_counts);
 381                 kfree(smc);
 382                 return ERR_PTR(r);
 383         }
 384
 385         r = ca_commit(&smc->old_counts, &smc->counts);
 386         if (r) {
 387                 ca_destroy(&smc->counts);
 388                 ca_destroy(&smc->old_counts);
 389                 kfree(smc);
 390                 return ERR_PTR(r);
 391         }
 392
 393         return &smc->sm;
 394 }
 395 EXPORT_SYMBOL_GPL(dm_sm_checker_create);
 396
 397 struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
 398 {
 399         int r;
 400         struct sm_checker *smc;
 401
 402         if (IS_ERR_OR_NULL(sm))
 403                 return ERR_PTR(-EINVAL);
 404
 405         smc = kmalloc(sizeof(*smc), GFP_KERNEL);
 406         if (!smc)
 407                 return ERR_PTR(-ENOMEM);
 408
 409         memcpy(&smc->sm, &ops_, sizeof(smc->sm));
 410         r = ca_create(&smc->old_counts, sm);
 411         if (r) {
 412                 kfree(smc);
 413                 return ERR_PTR(r);
 414         }
 415
 416         r = ca_create(&smc->counts, sm);
 417         if (r) {
 418                 ca_destroy(&smc->old_counts);
 419                 kfree(smc);
 420                 return ERR_PTR(r);
 421         }
 422
 423         smc->real_sm = sm;
 424         return &smc->sm;
 425 }
 426 EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);
 427
 428 /*----------------------------------------------------------------*/
 429
 430 #else
 431
 432 struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
 433 {
 434         return sm;
 435 }
 436 EXPORT_SYMBOL_GPL(dm_sm_checker_create);
 437
 438 struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
 439 {
 440         return sm;
 441 }
 442 EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);
 443
 444 /*----------------------------------------------------------------*/
 445
 446 #endif