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