1 /* 2 * Copyright (C) 2012 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm-cache-metadata.h" 8 9 #include "persistent-data/dm-array.h" 10 #include "persistent-data/dm-bitset.h" 11 #include "persistent-data/dm-space-map.h" 12 #include "persistent-data/dm-space-map-disk.h" 13 #include "persistent-data/dm-transaction-manager.h" 14 15 #include <linux/device-mapper.h> 16 17 /*----------------------------------------------------------------*/ 18 19 #define DM_MSG_PREFIX "cache metadata" 20 21 #define CACHE_SUPERBLOCK_MAGIC 06142003 22 #define CACHE_SUPERBLOCK_LOCATION 0 23 24 /* 25 * defines a range of metadata versions that this module can handle. 26 */ 27 #define MIN_CACHE_VERSION 1 28 #define MAX_CACHE_VERSION 1 29 30 #define CACHE_METADATA_CACHE_SIZE 64 31 32 /* 33 * 3 for btree insert + 34 * 2 for btree lookup used within space map 35 */ 36 #define CACHE_MAX_CONCURRENT_LOCKS 5 37 #define SPACE_MAP_ROOT_SIZE 128 38 39 enum superblock_flag_bits { 40 /* for spotting crashes that would invalidate the dirty bitset */ 41 CLEAN_SHUTDOWN, 42 /* metadata must be checked using the tools */ 43 NEEDS_CHECK, 44 }; 45 46 /* 47 * Each mapping from cache block -> origin block carries a set of flags. 48 */ 49 enum mapping_bits { 50 /* 51 * A valid mapping. Because we're using an array we clear this 52 * flag for an non existant mapping. 53 */ 54 M_VALID = 1, 55 56 /* 57 * The data on the cache is different from that on the origin. 58 */ 59 M_DIRTY = 2 60 }; 61 62 struct cache_disk_superblock { 63 __le32 csum; 64 __le32 flags; 65 __le64 blocknr; 66 67 __u8 uuid[16]; 68 __le64 magic; 69 __le32 version; 70 71 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 72 __le32 policy_hint_size; 73 74 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 75 __le64 mapping_root; 76 __le64 hint_root; 77 78 __le64 discard_root; 79 __le64 discard_block_size; 80 __le64 discard_nr_blocks; 81 82 __le32 data_block_size; 83 __le32 metadata_block_size; 84 __le32 cache_blocks; 85 86 __le32 compat_flags; 87 __le32 compat_ro_flags; 88 __le32 incompat_flags; 89 90 __le32 read_hits; 91 __le32 read_misses; 92 __le32 write_hits; 93 __le32 write_misses; 94 95 __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; 96 } __packed; 97 98 struct dm_cache_metadata { 99 atomic_t ref_count; 100 struct list_head list; 101 102 struct block_device *bdev; 103 struct dm_block_manager *bm; 104 struct dm_space_map *metadata_sm; 105 struct dm_transaction_manager *tm; 106 107 struct dm_array_info info; 108 struct dm_array_info hint_info; 109 struct dm_disk_bitset discard_info; 110 111 struct rw_semaphore root_lock; 112 unsigned long flags; 113 dm_block_t root; 114 dm_block_t hint_root; 115 dm_block_t discard_root; 116 117 sector_t discard_block_size; 118 dm_dblock_t discard_nr_blocks; 119 120 sector_t data_block_size; 121 dm_cblock_t cache_blocks; 122 bool changed:1; 123 bool clean_when_opened:1; 124 125 char policy_name[CACHE_POLICY_NAME_SIZE]; 126 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 127 size_t policy_hint_size; 128 struct dm_cache_statistics stats; 129 130 /* 131 * Reading the space map root can fail, so we read it into this 132 * buffer before the superblock is locked and updated. 133 */ 134 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 135 136 /* 137 * Set if a transaction has to be aborted but the attempt to roll 138 * back to the previous (good) transaction failed. The only 139 * metadata operation permissible in this state is the closing of 140 * the device. 141 */ 142 bool fail_io:1; 143 }; 144 145 /*------------------------------------------------------------------- 146 * superblock validator 147 *-----------------------------------------------------------------*/ 148 149 #define SUPERBLOCK_CSUM_XOR 9031977 150 151 static void sb_prepare_for_write(struct dm_block_validator *v, 152 struct dm_block *b, 153 size_t sb_block_size) 154 { 155 struct cache_disk_superblock *disk_super = dm_block_data(b); 156 157 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 158 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 159 sb_block_size - sizeof(__le32), 160 SUPERBLOCK_CSUM_XOR)); 161 } 162 163 static int check_metadata_version(struct cache_disk_superblock *disk_super) 164 { 165 uint32_t metadata_version = le32_to_cpu(disk_super->version); 166 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 167 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 168 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 169 return -EINVAL; 170 } 171 172 return 0; 173 } 174 175 static int sb_check(struct dm_block_validator *v, 176 struct dm_block *b, 177 size_t sb_block_size) 178 { 179 struct cache_disk_superblock *disk_super = dm_block_data(b); 180 __le32 csum_le; 181 182 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 183 DMERR("sb_check failed: blocknr %llu: wanted %llu", 184 le64_to_cpu(disk_super->blocknr), 185 (unsigned long long)dm_block_location(b)); 186 return -ENOTBLK; 187 } 188 189 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 190 DMERR("sb_check failed: magic %llu: wanted %llu", 191 le64_to_cpu(disk_super->magic), 192 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 193 return -EILSEQ; 194 } 195 196 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 197 sb_block_size - sizeof(__le32), 198 SUPERBLOCK_CSUM_XOR)); 199 if (csum_le != disk_super->csum) { 200 DMERR("sb_check failed: csum %u: wanted %u", 201 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 202 return -EILSEQ; 203 } 204 205 return check_metadata_version(disk_super); 206 } 207 208 static struct dm_block_validator sb_validator = { 209 .name = "superblock", 210 .prepare_for_write = sb_prepare_for_write, 211 .check = sb_check 212 }; 213 214 /*----------------------------------------------------------------*/ 215 216 static int superblock_read_lock(struct dm_cache_metadata *cmd, 217 struct dm_block **sblock) 218 { 219 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 220 &sb_validator, sblock); 221 } 222 223 static int superblock_lock_zero(struct dm_cache_metadata *cmd, 224 struct dm_block **sblock) 225 { 226 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 227 &sb_validator, sblock); 228 } 229 230 static int superblock_lock(struct dm_cache_metadata *cmd, 231 struct dm_block **sblock) 232 { 233 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 234 &sb_validator, sblock); 235 } 236 237 /*----------------------------------------------------------------*/ 238 239 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 240 { 241 int r; 242 unsigned i; 243 struct dm_block *b; 244 __le64 *data_le, zero = cpu_to_le64(0); 245 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 246 247 /* 248 * We can't use a validator here - it may be all zeroes. 249 */ 250 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 251 if (r) 252 return r; 253 254 data_le = dm_block_data(b); 255 *result = true; 256 for (i = 0; i < sb_block_size; i++) { 257 if (data_le[i] != zero) { 258 *result = false; 259 break; 260 } 261 } 262 263 dm_bm_unlock(b); 264 265 return 0; 266 } 267 268 static void __setup_mapping_info(struct dm_cache_metadata *cmd) 269 { 270 struct dm_btree_value_type vt; 271 272 vt.context = NULL; 273 vt.size = sizeof(__le64); 274 vt.inc = NULL; 275 vt.dec = NULL; 276 vt.equal = NULL; 277 dm_array_info_init(&cmd->info, cmd->tm, &vt); 278 279 if (cmd->policy_hint_size) { 280 vt.size = sizeof(__le32); 281 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 282 } 283 } 284 285 static int __save_sm_root(struct dm_cache_metadata *cmd) 286 { 287 int r; 288 size_t metadata_len; 289 290 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 291 if (r < 0) 292 return r; 293 294 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, 295 metadata_len); 296 } 297 298 static void __copy_sm_root(struct dm_cache_metadata *cmd, 299 struct cache_disk_superblock *disk_super) 300 { 301 memcpy(&disk_super->metadata_space_map_root, 302 &cmd->metadata_space_map_root, 303 sizeof(cmd->metadata_space_map_root)); 304 } 305 306 static int __write_initial_superblock(struct dm_cache_metadata *cmd) 307 { 308 int r; 309 struct dm_block *sblock; 310 struct cache_disk_superblock *disk_super; 311 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 312 313 /* FIXME: see if we can lose the max sectors limit */ 314 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 315 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 316 317 r = dm_tm_pre_commit(cmd->tm); 318 if (r < 0) 319 return r; 320 321 /* 322 * dm_sm_copy_root() can fail. So we need to do it before we start 323 * updating the superblock. 324 */ 325 r = __save_sm_root(cmd); 326 if (r) 327 return r; 328 329 r = superblock_lock_zero(cmd, &sblock); 330 if (r) 331 return r; 332 333 disk_super = dm_block_data(sblock); 334 disk_super->flags = 0; 335 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 336 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 337 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION); 338 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 339 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 340 disk_super->policy_hint_size = 0; 341 342 __copy_sm_root(cmd, disk_super); 343 344 disk_super->mapping_root = cpu_to_le64(cmd->root); 345 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 346 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 347 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 348 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 349 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE); 350 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 351 disk_super->cache_blocks = cpu_to_le32(0); 352 353 disk_super->read_hits = cpu_to_le32(0); 354 disk_super->read_misses = cpu_to_le32(0); 355 disk_super->write_hits = cpu_to_le32(0); 356 disk_super->write_misses = cpu_to_le32(0); 357 358 return dm_tm_commit(cmd->tm, sblock); 359 } 360 361 static int __format_metadata(struct dm_cache_metadata *cmd) 362 { 363 int r; 364 365 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 366 &cmd->tm, &cmd->metadata_sm); 367 if (r < 0) { 368 DMERR("tm_create_with_sm failed"); 369 return r; 370 } 371 372 __setup_mapping_info(cmd); 373 374 r = dm_array_empty(&cmd->info, &cmd->root); 375 if (r < 0) 376 goto bad; 377 378 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 379 380 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 381 if (r < 0) 382 goto bad; 383 384 cmd->discard_block_size = 0; 385 cmd->discard_nr_blocks = 0; 386 387 r = __write_initial_superblock(cmd); 388 if (r) 389 goto bad; 390 391 cmd->clean_when_opened = true; 392 return 0; 393 394 bad: 395 dm_tm_destroy(cmd->tm); 396 dm_sm_destroy(cmd->metadata_sm); 397 398 return r; 399 } 400 401 static int __check_incompat_features(struct cache_disk_superblock *disk_super, 402 struct dm_cache_metadata *cmd) 403 { 404 uint32_t features; 405 406 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 407 if (features) { 408 DMERR("could not access metadata due to unsupported optional features (%lx).", 409 (unsigned long)features); 410 return -EINVAL; 411 } 412 413 /* 414 * Check for read-only metadata to skip the following RDWR checks. 415 */ 416 if (get_disk_ro(cmd->bdev->bd_disk)) 417 return 0; 418 419 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 420 if (features) { 421 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 422 (unsigned long)features); 423 return -EINVAL; 424 } 425 426 return 0; 427 } 428 429 static int __open_metadata(struct dm_cache_metadata *cmd) 430 { 431 int r; 432 struct dm_block *sblock; 433 struct cache_disk_superblock *disk_super; 434 unsigned long sb_flags; 435 436 r = superblock_read_lock(cmd, &sblock); 437 if (r < 0) { 438 DMERR("couldn't read lock superblock"); 439 return r; 440 } 441 442 disk_super = dm_block_data(sblock); 443 444 /* Verify the data block size hasn't changed */ 445 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) { 446 DMERR("changing the data block size (from %u to %llu) is not supported", 447 le32_to_cpu(disk_super->data_block_size), 448 (unsigned long long)cmd->data_block_size); 449 r = -EINVAL; 450 goto bad; 451 } 452 453 r = __check_incompat_features(disk_super, cmd); 454 if (r < 0) 455 goto bad; 456 457 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 458 disk_super->metadata_space_map_root, 459 sizeof(disk_super->metadata_space_map_root), 460 &cmd->tm, &cmd->metadata_sm); 461 if (r < 0) { 462 DMERR("tm_open_with_sm failed"); 463 goto bad; 464 } 465 466 __setup_mapping_info(cmd); 467 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 468 sb_flags = le32_to_cpu(disk_super->flags); 469 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 470 dm_bm_unlock(sblock); 471 472 return 0; 473 474 bad: 475 dm_bm_unlock(sblock); 476 return r; 477 } 478 479 static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 480 bool format_device) 481 { 482 int r; 483 bool unformatted = false; 484 485 r = __superblock_all_zeroes(cmd->bm, &unformatted); 486 if (r) 487 return r; 488 489 if (unformatted) 490 return format_device ? __format_metadata(cmd) : -EPERM; 491 492 return __open_metadata(cmd); 493 } 494 495 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 496 bool may_format_device) 497 { 498 int r; 499 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, 500 CACHE_METADATA_CACHE_SIZE, 501 CACHE_MAX_CONCURRENT_LOCKS); 502 if (IS_ERR(cmd->bm)) { 503 DMERR("could not create block manager"); 504 return PTR_ERR(cmd->bm); 505 } 506 507 r = __open_or_format_metadata(cmd, may_format_device); 508 if (r) 509 dm_block_manager_destroy(cmd->bm); 510 511 return r; 512 } 513 514 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 515 { 516 dm_sm_destroy(cmd->metadata_sm); 517 dm_tm_destroy(cmd->tm); 518 dm_block_manager_destroy(cmd->bm); 519 } 520 521 typedef unsigned long (*flags_mutator)(unsigned long); 522 523 static void update_flags(struct cache_disk_superblock *disk_super, 524 flags_mutator mutator) 525 { 526 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 527 disk_super->flags = cpu_to_le32(sb_flags); 528 } 529 530 static unsigned long set_clean_shutdown(unsigned long flags) 531 { 532 set_bit(CLEAN_SHUTDOWN, &flags); 533 return flags; 534 } 535 536 static unsigned long clear_clean_shutdown(unsigned long flags) 537 { 538 clear_bit(CLEAN_SHUTDOWN, &flags); 539 return flags; 540 } 541 542 static void read_superblock_fields(struct dm_cache_metadata *cmd, 543 struct cache_disk_superblock *disk_super) 544 { 545 cmd->flags = le32_to_cpu(disk_super->flags); 546 cmd->root = le64_to_cpu(disk_super->mapping_root); 547 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 548 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 549 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 550 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 551 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 552 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 553 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 554 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 555 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 556 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 557 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 558 559 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 560 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 561 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 562 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 563 564 cmd->changed = false; 565 } 566 567 /* 568 * The mutator updates the superblock flags. 569 */ 570 static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 571 flags_mutator mutator) 572 { 573 int r; 574 struct cache_disk_superblock *disk_super; 575 struct dm_block *sblock; 576 577 r = superblock_lock(cmd, &sblock); 578 if (r) 579 return r; 580 581 disk_super = dm_block_data(sblock); 582 update_flags(disk_super, mutator); 583 read_superblock_fields(cmd, disk_super); 584 dm_bm_unlock(sblock); 585 586 return dm_bm_flush(cmd->bm); 587 } 588 589 static int __begin_transaction(struct dm_cache_metadata *cmd) 590 { 591 int r; 592 struct cache_disk_superblock *disk_super; 593 struct dm_block *sblock; 594 595 /* 596 * We re-read the superblock every time. Shouldn't need to do this 597 * really. 598 */ 599 r = superblock_read_lock(cmd, &sblock); 600 if (r) 601 return r; 602 603 disk_super = dm_block_data(sblock); 604 read_superblock_fields(cmd, disk_super); 605 dm_bm_unlock(sblock); 606 607 return 0; 608 } 609 610 static int __commit_transaction(struct dm_cache_metadata *cmd, 611 flags_mutator mutator) 612 { 613 int r; 614 struct cache_disk_superblock *disk_super; 615 struct dm_block *sblock; 616 617 /* 618 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 619 */ 620 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 621 622 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 623 &cmd->discard_root); 624 if (r) 625 return r; 626 627 r = dm_tm_pre_commit(cmd->tm); 628 if (r < 0) 629 return r; 630 631 r = __save_sm_root(cmd); 632 if (r) 633 return r; 634 635 r = superblock_lock(cmd, &sblock); 636 if (r) 637 return r; 638 639 disk_super = dm_block_data(sblock); 640 641 disk_super->flags = cpu_to_le32(cmd->flags); 642 if (mutator) 643 update_flags(disk_super, mutator); 644 645 disk_super->mapping_root = cpu_to_le64(cmd->root); 646 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 647 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 648 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 649 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 650 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 651 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 652 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 653 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 654 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 655 656 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 657 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 658 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 659 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 660 __copy_sm_root(cmd, disk_super); 661 662 return dm_tm_commit(cmd->tm, sblock); 663 } 664 665 /*----------------------------------------------------------------*/ 666 667 /* 668 * The mappings are held in a dm-array that has 64-bit values stored in 669 * little-endian format. The index is the cblock, the high 48bits of the 670 * value are the oblock and the low 16 bit the flags. 671 */ 672 #define FLAGS_MASK ((1 << 16) - 1) 673 674 static __le64 pack_value(dm_oblock_t block, unsigned flags) 675 { 676 uint64_t value = from_oblock(block); 677 value <<= 16; 678 value = value | (flags & FLAGS_MASK); 679 return cpu_to_le64(value); 680 } 681 682 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 683 { 684 uint64_t value = le64_to_cpu(value_le); 685 uint64_t b = value >> 16; 686 *block = to_oblock(b); 687 *flags = value & FLAGS_MASK; 688 } 689 690 /*----------------------------------------------------------------*/ 691 692 static struct dm_cache_metadata *metadata_open(struct block_device *bdev, 693 sector_t data_block_size, 694 bool may_format_device, 695 size_t policy_hint_size) 696 { 697 int r; 698 struct dm_cache_metadata *cmd; 699 700 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 701 if (!cmd) { 702 DMERR("could not allocate metadata struct"); 703 return ERR_PTR(-ENOMEM); 704 } 705 706 atomic_set(&cmd->ref_count, 1); 707 init_rwsem(&cmd->root_lock); 708 cmd->bdev = bdev; 709 cmd->data_block_size = data_block_size; 710 cmd->cache_blocks = 0; 711 cmd->policy_hint_size = policy_hint_size; 712 cmd->changed = true; 713 cmd->fail_io = false; 714 715 r = __create_persistent_data_objects(cmd, may_format_device); 716 if (r) { 717 kfree(cmd); 718 return ERR_PTR(r); 719 } 720 721 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 722 if (r < 0) { 723 dm_cache_metadata_close(cmd); 724 return ERR_PTR(r); 725 } 726 727 return cmd; 728 } 729 730 /* 731 * We keep a little list of ref counted metadata objects to prevent two 732 * different target instances creating separate bufio instances. This is 733 * an issue if a table is reloaded before the suspend. 734 */ 735 static DEFINE_MUTEX(table_lock); 736 static LIST_HEAD(table); 737 738 static struct dm_cache_metadata *lookup(struct block_device *bdev) 739 { 740 struct dm_cache_metadata *cmd; 741 742 list_for_each_entry(cmd, &table, list) 743 if (cmd->bdev == bdev) { 744 atomic_inc(&cmd->ref_count); 745 return cmd; 746 } 747 748 return NULL; 749 } 750 751 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, 752 sector_t data_block_size, 753 bool may_format_device, 754 size_t policy_hint_size) 755 { 756 struct dm_cache_metadata *cmd, *cmd2; 757 758 mutex_lock(&table_lock); 759 cmd = lookup(bdev); 760 mutex_unlock(&table_lock); 761 762 if (cmd) 763 return cmd; 764 765 cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size); 766 if (!IS_ERR(cmd)) { 767 mutex_lock(&table_lock); 768 cmd2 = lookup(bdev); 769 if (cmd2) { 770 mutex_unlock(&table_lock); 771 __destroy_persistent_data_objects(cmd); 772 kfree(cmd); 773 return cmd2; 774 } 775 list_add(&cmd->list, &table); 776 mutex_unlock(&table_lock); 777 } 778 779 return cmd; 780 } 781 782 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) 783 { 784 if (cmd->data_block_size != data_block_size) { 785 DMERR("data_block_size (%llu) different from that in metadata (%llu)\n", 786 (unsigned long long) data_block_size, 787 (unsigned long long) cmd->data_block_size); 788 return false; 789 } 790 791 return true; 792 } 793 794 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 795 sector_t data_block_size, 796 bool may_format_device, 797 size_t policy_hint_size) 798 { 799 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, 800 may_format_device, policy_hint_size); 801 802 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { 803 dm_cache_metadata_close(cmd); 804 return ERR_PTR(-EINVAL); 805 } 806 807 return cmd; 808 } 809 810 void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 811 { 812 if (atomic_dec_and_test(&cmd->ref_count)) { 813 mutex_lock(&table_lock); 814 list_del(&cmd->list); 815 mutex_unlock(&table_lock); 816 817 if (!cmd->fail_io) 818 __destroy_persistent_data_objects(cmd); 819 kfree(cmd); 820 } 821 } 822 823 /* 824 * Checks that the given cache block is either unmapped or clean. 825 */ 826 static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b, 827 bool *result) 828 { 829 int r; 830 __le64 value; 831 dm_oblock_t ob; 832 unsigned flags; 833 834 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 835 if (r) { 836 DMERR("block_unmapped_or_clean failed"); 837 return r; 838 } 839 840 unpack_value(value, &ob, &flags); 841 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 842 843 return 0; 844 } 845 846 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 847 dm_cblock_t begin, dm_cblock_t end, 848 bool *result) 849 { 850 int r; 851 *result = true; 852 853 while (begin != end) { 854 r = block_unmapped_or_clean(cmd, begin, result); 855 if (r) 856 return r; 857 858 if (!*result) { 859 DMERR("cache block %llu is dirty", 860 (unsigned long long) from_cblock(begin)); 861 return 0; 862 } 863 864 begin = to_cblock(from_cblock(begin) + 1); 865 } 866 867 return 0; 868 } 869 870 #define WRITE_LOCK(cmd) \ 871 down_write(&cmd->root_lock); \ 872 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ 873 up_write(&cmd->root_lock); \ 874 return -EINVAL; \ 875 } 876 877 #define WRITE_LOCK_VOID(cmd) \ 878 down_write(&cmd->root_lock); \ 879 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ 880 up_write(&cmd->root_lock); \ 881 return; \ 882 } 883 884 #define WRITE_UNLOCK(cmd) \ 885 up_write(&cmd->root_lock) 886 887 #define READ_LOCK(cmd) \ 888 down_read(&cmd->root_lock); \ 889 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ 890 up_read(&cmd->root_lock); \ 891 return -EINVAL; \ 892 } 893 894 #define READ_LOCK_VOID(cmd) \ 895 down_read(&cmd->root_lock); \ 896 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { \ 897 up_read(&cmd->root_lock); \ 898 return; \ 899 } 900 901 #define READ_UNLOCK(cmd) \ 902 up_read(&cmd->root_lock) 903 904 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 905 { 906 int r; 907 bool clean; 908 __le64 null_mapping = pack_value(0, 0); 909 910 WRITE_LOCK(cmd); 911 __dm_bless_for_disk(&null_mapping); 912 913 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 914 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 915 if (r) { 916 __dm_unbless_for_disk(&null_mapping); 917 goto out; 918 } 919 920 if (!clean) { 921 DMERR("unable to shrink cache due to dirty blocks"); 922 r = -EINVAL; 923 __dm_unbless_for_disk(&null_mapping); 924 goto out; 925 } 926 } 927 928 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 929 from_cblock(new_cache_size), 930 &null_mapping, &cmd->root); 931 if (!r) 932 cmd->cache_blocks = new_cache_size; 933 cmd->changed = true; 934 935 out: 936 WRITE_UNLOCK(cmd); 937 938 return r; 939 } 940 941 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 942 sector_t discard_block_size, 943 dm_dblock_t new_nr_entries) 944 { 945 int r; 946 947 WRITE_LOCK(cmd); 948 r = dm_bitset_resize(&cmd->discard_info, 949 cmd->discard_root, 950 from_dblock(cmd->discard_nr_blocks), 951 from_dblock(new_nr_entries), 952 false, &cmd->discard_root); 953 if (!r) { 954 cmd->discard_block_size = discard_block_size; 955 cmd->discard_nr_blocks = new_nr_entries; 956 } 957 958 cmd->changed = true; 959 WRITE_UNLOCK(cmd); 960 961 return r; 962 } 963 964 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 965 { 966 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 967 from_dblock(b), &cmd->discard_root); 968 } 969 970 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 971 { 972 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 973 from_dblock(b), &cmd->discard_root); 974 } 975 976 static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b, 977 bool *is_discarded) 978 { 979 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, 980 from_dblock(b), &cmd->discard_root, 981 is_discarded); 982 } 983 984 static int __discard(struct dm_cache_metadata *cmd, 985 dm_dblock_t dblock, bool discard) 986 { 987 int r; 988 989 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 990 if (r) 991 return r; 992 993 cmd->changed = true; 994 return 0; 995 } 996 997 int dm_cache_set_discard(struct dm_cache_metadata *cmd, 998 dm_dblock_t dblock, bool discard) 999 { 1000 int r; 1001 1002 WRITE_LOCK(cmd); 1003 r = __discard(cmd, dblock, discard); 1004 WRITE_UNLOCK(cmd); 1005 1006 return r; 1007 } 1008 1009 static int __load_discards(struct dm_cache_metadata *cmd, 1010 load_discard_fn fn, void *context) 1011 { 1012 int r = 0; 1013 dm_block_t b; 1014 bool discard; 1015 1016 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1017 dm_dblock_t dblock = to_dblock(b); 1018 1019 if (cmd->clean_when_opened) { 1020 r = __is_discarded(cmd, dblock, &discard); 1021 if (r) 1022 return r; 1023 } else 1024 discard = false; 1025 1026 r = fn(context, cmd->discard_block_size, dblock, discard); 1027 if (r) 1028 break; 1029 } 1030 1031 return r; 1032 } 1033 1034 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 1035 load_discard_fn fn, void *context) 1036 { 1037 int r; 1038 1039 READ_LOCK(cmd); 1040 r = __load_discards(cmd, fn, context); 1041 READ_UNLOCK(cmd); 1042 1043 return r; 1044 } 1045 1046 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result) 1047 { 1048 READ_LOCK(cmd); 1049 *result = cmd->cache_blocks; 1050 READ_UNLOCK(cmd); 1051 1052 return 0; 1053 } 1054 1055 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1056 { 1057 int r; 1058 __le64 value = pack_value(0, 0); 1059 1060 __dm_bless_for_disk(&value); 1061 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1062 &value, &cmd->root); 1063 if (r) 1064 return r; 1065 1066 cmd->changed = true; 1067 return 0; 1068 } 1069 1070 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1071 { 1072 int r; 1073 1074 WRITE_LOCK(cmd); 1075 r = __remove(cmd, cblock); 1076 WRITE_UNLOCK(cmd); 1077 1078 return r; 1079 } 1080 1081 static int __insert(struct dm_cache_metadata *cmd, 1082 dm_cblock_t cblock, dm_oblock_t oblock) 1083 { 1084 int r; 1085 __le64 value = pack_value(oblock, M_VALID); 1086 __dm_bless_for_disk(&value); 1087 1088 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1089 &value, &cmd->root); 1090 if (r) 1091 return r; 1092 1093 cmd->changed = true; 1094 return 0; 1095 } 1096 1097 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 1098 dm_cblock_t cblock, dm_oblock_t oblock) 1099 { 1100 int r; 1101 1102 WRITE_LOCK(cmd); 1103 r = __insert(cmd, cblock, oblock); 1104 WRITE_UNLOCK(cmd); 1105 1106 return r; 1107 } 1108 1109 struct thunk { 1110 load_mapping_fn fn; 1111 void *context; 1112 1113 struct dm_cache_metadata *cmd; 1114 bool respect_dirty_flags; 1115 bool hints_valid; 1116 }; 1117 1118 static bool policy_unchanged(struct dm_cache_metadata *cmd, 1119 struct dm_cache_policy *policy) 1120 { 1121 const char *policy_name = dm_cache_policy_get_name(policy); 1122 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1123 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 1124 1125 /* 1126 * Ensure policy names match. 1127 */ 1128 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 1129 return false; 1130 1131 /* 1132 * Ensure policy major versions match. 1133 */ 1134 if (cmd->policy_version[0] != policy_version[0]) 1135 return false; 1136 1137 /* 1138 * Ensure policy hint sizes match. 1139 */ 1140 if (cmd->policy_hint_size != policy_hint_size) 1141 return false; 1142 1143 return true; 1144 } 1145 1146 static bool hints_array_initialized(struct dm_cache_metadata *cmd) 1147 { 1148 return cmd->hint_root && cmd->policy_hint_size; 1149 } 1150 1151 static bool hints_array_available(struct dm_cache_metadata *cmd, 1152 struct dm_cache_policy *policy) 1153 { 1154 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 1155 hints_array_initialized(cmd); 1156 } 1157 1158 static int __load_mapping(void *context, uint64_t cblock, void *leaf) 1159 { 1160 int r = 0; 1161 bool dirty; 1162 __le64 value; 1163 __le32 hint_value = 0; 1164 dm_oblock_t oblock; 1165 unsigned flags; 1166 struct thunk *thunk = context; 1167 struct dm_cache_metadata *cmd = thunk->cmd; 1168 1169 memcpy(&value, leaf, sizeof(value)); 1170 unpack_value(value, &oblock, &flags); 1171 1172 if (flags & M_VALID) { 1173 if (thunk->hints_valid) { 1174 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, 1175 cblock, &hint_value); 1176 if (r && r != -ENODATA) 1177 return r; 1178 } 1179 1180 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; 1181 r = thunk->fn(thunk->context, oblock, to_cblock(cblock), 1182 dirty, le32_to_cpu(hint_value), thunk->hints_valid); 1183 } 1184 1185 return r; 1186 } 1187 1188 static int __load_mappings(struct dm_cache_metadata *cmd, 1189 struct dm_cache_policy *policy, 1190 load_mapping_fn fn, void *context) 1191 { 1192 struct thunk thunk; 1193 1194 thunk.fn = fn; 1195 thunk.context = context; 1196 1197 thunk.cmd = cmd; 1198 thunk.respect_dirty_flags = cmd->clean_when_opened; 1199 thunk.hints_valid = hints_array_available(cmd, policy); 1200 1201 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); 1202 } 1203 1204 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1205 struct dm_cache_policy *policy, 1206 load_mapping_fn fn, void *context) 1207 { 1208 int r; 1209 1210 READ_LOCK(cmd); 1211 r = __load_mappings(cmd, policy, fn, context); 1212 READ_UNLOCK(cmd); 1213 1214 return r; 1215 } 1216 1217 static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1218 { 1219 int r = 0; 1220 __le64 value; 1221 dm_oblock_t oblock; 1222 unsigned flags; 1223 1224 memcpy(&value, leaf, sizeof(value)); 1225 unpack_value(value, &oblock, &flags); 1226 1227 return r; 1228 } 1229 1230 static int __dump_mappings(struct dm_cache_metadata *cmd) 1231 { 1232 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1233 } 1234 1235 void dm_cache_dump(struct dm_cache_metadata *cmd) 1236 { 1237 READ_LOCK_VOID(cmd); 1238 __dump_mappings(cmd); 1239 READ_UNLOCK(cmd); 1240 } 1241 1242 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1243 { 1244 int r; 1245 1246 READ_LOCK(cmd); 1247 r = cmd->changed; 1248 READ_UNLOCK(cmd); 1249 1250 return r; 1251 } 1252 1253 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1254 { 1255 int r; 1256 unsigned flags; 1257 dm_oblock_t oblock; 1258 __le64 value; 1259 1260 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1261 if (r) 1262 return r; 1263 1264 unpack_value(value, &oblock, &flags); 1265 1266 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1267 /* nothing to be done */ 1268 return 0; 1269 1270 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1271 __dm_bless_for_disk(&value); 1272 1273 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1274 &value, &cmd->root); 1275 if (r) 1276 return r; 1277 1278 cmd->changed = true; 1279 return 0; 1280 1281 } 1282 1283 int dm_cache_set_dirty(struct dm_cache_metadata *cmd, 1284 dm_cblock_t cblock, bool dirty) 1285 { 1286 int r; 1287 1288 WRITE_LOCK(cmd); 1289 r = __dirty(cmd, cblock, dirty); 1290 WRITE_UNLOCK(cmd); 1291 1292 return r; 1293 } 1294 1295 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1296 struct dm_cache_statistics *stats) 1297 { 1298 READ_LOCK_VOID(cmd); 1299 *stats = cmd->stats; 1300 READ_UNLOCK(cmd); 1301 } 1302 1303 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1304 struct dm_cache_statistics *stats) 1305 { 1306 WRITE_LOCK_VOID(cmd); 1307 cmd->stats = *stats; 1308 WRITE_UNLOCK(cmd); 1309 } 1310 1311 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1312 { 1313 int r; 1314 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1315 clear_clean_shutdown); 1316 1317 WRITE_LOCK(cmd); 1318 r = __commit_transaction(cmd, mutator); 1319 if (r) 1320 goto out; 1321 1322 r = __begin_transaction(cmd); 1323 1324 out: 1325 WRITE_UNLOCK(cmd); 1326 return r; 1327 } 1328 1329 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1330 dm_block_t *result) 1331 { 1332 int r = -EINVAL; 1333 1334 READ_LOCK(cmd); 1335 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1336 READ_UNLOCK(cmd); 1337 1338 return r; 1339 } 1340 1341 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1342 dm_block_t *result) 1343 { 1344 int r = -EINVAL; 1345 1346 READ_LOCK(cmd); 1347 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1348 READ_UNLOCK(cmd); 1349 1350 return r; 1351 } 1352 1353 /*----------------------------------------------------------------*/ 1354 1355 static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1356 { 1357 int r; 1358 __le32 value; 1359 size_t hint_size; 1360 const char *policy_name = dm_cache_policy_get_name(policy); 1361 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1362 1363 if (!policy_name[0] || 1364 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1365 return -EINVAL; 1366 1367 if (!policy_unchanged(cmd, policy)) { 1368 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1369 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1370 1371 hint_size = dm_cache_policy_get_hint_size(policy); 1372 if (!hint_size) 1373 return 0; /* short-circuit hints initialization */ 1374 cmd->policy_hint_size = hint_size; 1375 1376 if (cmd->hint_root) { 1377 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1378 if (r) 1379 return r; 1380 } 1381 1382 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); 1383 if (r) 1384 return r; 1385 1386 value = cpu_to_le32(0); 1387 __dm_bless_for_disk(&value); 1388 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, 1389 from_cblock(cmd->cache_blocks), 1390 &value, &cmd->hint_root); 1391 if (r) 1392 return r; 1393 } 1394 1395 return 0; 1396 } 1397 1398 static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint) 1399 { 1400 struct dm_cache_metadata *cmd = context; 1401 __le32 value = cpu_to_le32(hint); 1402 int r; 1403 1404 __dm_bless_for_disk(&value); 1405 1406 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, 1407 from_cblock(cblock), &value, &cmd->hint_root); 1408 cmd->changed = true; 1409 1410 return r; 1411 } 1412 1413 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1414 { 1415 int r; 1416 1417 r = begin_hints(cmd, policy); 1418 if (r) { 1419 DMERR("begin_hints failed"); 1420 return r; 1421 } 1422 1423 return policy_walk_mappings(policy, save_hint, cmd); 1424 } 1425 1426 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1427 { 1428 int r; 1429 1430 WRITE_LOCK(cmd); 1431 r = write_hints(cmd, policy); 1432 WRITE_UNLOCK(cmd); 1433 1434 return r; 1435 } 1436 1437 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1438 { 1439 int r; 1440 1441 READ_LOCK(cmd); 1442 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1443 READ_UNLOCK(cmd); 1444 1445 return r; 1446 } 1447 1448 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) 1449 { 1450 WRITE_LOCK_VOID(cmd); 1451 dm_bm_set_read_only(cmd->bm); 1452 WRITE_UNLOCK(cmd); 1453 } 1454 1455 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) 1456 { 1457 WRITE_LOCK_VOID(cmd); 1458 dm_bm_set_read_write(cmd->bm); 1459 WRITE_UNLOCK(cmd); 1460 } 1461 1462 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) 1463 { 1464 int r; 1465 struct dm_block *sblock; 1466 struct cache_disk_superblock *disk_super; 1467 1468 WRITE_LOCK(cmd); 1469 set_bit(NEEDS_CHECK, &cmd->flags); 1470 1471 r = superblock_lock(cmd, &sblock); 1472 if (r) { 1473 DMERR("couldn't read superblock"); 1474 goto out; 1475 } 1476 1477 disk_super = dm_block_data(sblock); 1478 disk_super->flags = cpu_to_le32(cmd->flags); 1479 1480 dm_bm_unlock(sblock); 1481 1482 out: 1483 WRITE_UNLOCK(cmd); 1484 return r; 1485 } 1486 1487 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) 1488 { 1489 READ_LOCK(cmd); 1490 *result = !!test_bit(NEEDS_CHECK, &cmd->flags); 1491 READ_UNLOCK(cmd); 1492 1493 return 0; 1494 } 1495 1496 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) 1497 { 1498 int r; 1499 1500 WRITE_LOCK(cmd); 1501 __destroy_persistent_data_objects(cmd); 1502 r = __create_persistent_data_objects(cmd, false); 1503 if (r) 1504 cmd->fail_io = true; 1505 WRITE_UNLOCK(cmd); 1506 1507 return r; 1508 } 1509