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 #include <linux/refcount.h> 17 18 /*----------------------------------------------------------------*/ 19 20 #define DM_MSG_PREFIX "cache metadata" 21 22 #define CACHE_SUPERBLOCK_MAGIC 06142003 23 #define CACHE_SUPERBLOCK_LOCATION 0 24 25 /* 26 * defines a range of metadata versions that this module can handle. 27 */ 28 #define MIN_CACHE_VERSION 1 29 #define MAX_CACHE_VERSION 2 30 31 /* 32 * 3 for btree insert + 33 * 2 for btree lookup used within space map 34 */ 35 #define CACHE_MAX_CONCURRENT_LOCKS 5 36 #define SPACE_MAP_ROOT_SIZE 128 37 38 enum superblock_flag_bits { 39 /* for spotting crashes that would invalidate the dirty bitset */ 40 CLEAN_SHUTDOWN, 41 /* metadata must be checked using the tools */ 42 NEEDS_CHECK, 43 }; 44 45 /* 46 * Each mapping from cache block -> origin block carries a set of flags. 47 */ 48 enum mapping_bits { 49 /* 50 * A valid mapping. Because we're using an array we clear this 51 * flag for an non existant mapping. 52 */ 53 M_VALID = 1, 54 55 /* 56 * The data on the cache is different from that on the origin. 57 * This flag is only used by metadata format 1. 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 97 /* 98 * Metadata format 2 fields. 99 */ 100 __le64 dirty_root; 101 } __packed; 102 103 struct dm_cache_metadata { 104 refcount_t ref_count; 105 struct list_head list; 106 107 unsigned version; 108 struct block_device *bdev; 109 struct dm_block_manager *bm; 110 struct dm_space_map *metadata_sm; 111 struct dm_transaction_manager *tm; 112 113 struct dm_array_info info; 114 struct dm_array_info hint_info; 115 struct dm_disk_bitset discard_info; 116 117 struct rw_semaphore root_lock; 118 unsigned long flags; 119 dm_block_t root; 120 dm_block_t hint_root; 121 dm_block_t discard_root; 122 123 sector_t discard_block_size; 124 dm_dblock_t discard_nr_blocks; 125 126 sector_t data_block_size; 127 dm_cblock_t cache_blocks; 128 bool changed:1; 129 bool clean_when_opened:1; 130 131 char policy_name[CACHE_POLICY_NAME_SIZE]; 132 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 133 size_t policy_hint_size; 134 struct dm_cache_statistics stats; 135 136 /* 137 * Reading the space map root can fail, so we read it into this 138 * buffer before the superblock is locked and updated. 139 */ 140 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 141 142 /* 143 * Set if a transaction has to be aborted but the attempt to roll 144 * back to the previous (good) transaction failed. The only 145 * metadata operation permissible in this state is the closing of 146 * the device. 147 */ 148 bool fail_io:1; 149 150 /* 151 * Metadata format 2 fields. 152 */ 153 dm_block_t dirty_root; 154 struct dm_disk_bitset dirty_info; 155 156 /* 157 * These structures are used when loading metadata. They're too 158 * big to put on the stack. 159 */ 160 struct dm_array_cursor mapping_cursor; 161 struct dm_array_cursor hint_cursor; 162 struct dm_bitset_cursor dirty_cursor; 163 }; 164 165 /*------------------------------------------------------------------- 166 * superblock validator 167 *-----------------------------------------------------------------*/ 168 169 #define SUPERBLOCK_CSUM_XOR 9031977 170 171 static void sb_prepare_for_write(struct dm_block_validator *v, 172 struct dm_block *b, 173 size_t sb_block_size) 174 { 175 struct cache_disk_superblock *disk_super = dm_block_data(b); 176 177 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 178 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 179 sb_block_size - sizeof(__le32), 180 SUPERBLOCK_CSUM_XOR)); 181 } 182 183 static int check_metadata_version(struct cache_disk_superblock *disk_super) 184 { 185 uint32_t metadata_version = le32_to_cpu(disk_super->version); 186 187 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 188 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 189 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 190 return -EINVAL; 191 } 192 193 return 0; 194 } 195 196 static int sb_check(struct dm_block_validator *v, 197 struct dm_block *b, 198 size_t sb_block_size) 199 { 200 struct cache_disk_superblock *disk_super = dm_block_data(b); 201 __le32 csum_le; 202 203 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 204 DMERR("sb_check failed: blocknr %llu: wanted %llu", 205 le64_to_cpu(disk_super->blocknr), 206 (unsigned long long)dm_block_location(b)); 207 return -ENOTBLK; 208 } 209 210 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 211 DMERR("sb_check failed: magic %llu: wanted %llu", 212 le64_to_cpu(disk_super->magic), 213 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 214 return -EILSEQ; 215 } 216 217 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 218 sb_block_size - sizeof(__le32), 219 SUPERBLOCK_CSUM_XOR)); 220 if (csum_le != disk_super->csum) { 221 DMERR("sb_check failed: csum %u: wanted %u", 222 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 223 return -EILSEQ; 224 } 225 226 return check_metadata_version(disk_super); 227 } 228 229 static struct dm_block_validator sb_validator = { 230 .name = "superblock", 231 .prepare_for_write = sb_prepare_for_write, 232 .check = sb_check 233 }; 234 235 /*----------------------------------------------------------------*/ 236 237 static int superblock_read_lock(struct dm_cache_metadata *cmd, 238 struct dm_block **sblock) 239 { 240 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 241 &sb_validator, sblock); 242 } 243 244 static int superblock_lock_zero(struct dm_cache_metadata *cmd, 245 struct dm_block **sblock) 246 { 247 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 248 &sb_validator, sblock); 249 } 250 251 static int superblock_lock(struct dm_cache_metadata *cmd, 252 struct dm_block **sblock) 253 { 254 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 255 &sb_validator, sblock); 256 } 257 258 /*----------------------------------------------------------------*/ 259 260 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 261 { 262 int r; 263 unsigned i; 264 struct dm_block *b; 265 __le64 *data_le, zero = cpu_to_le64(0); 266 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 267 268 /* 269 * We can't use a validator here - it may be all zeroes. 270 */ 271 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 272 if (r) 273 return r; 274 275 data_le = dm_block_data(b); 276 *result = true; 277 for (i = 0; i < sb_block_size; i++) { 278 if (data_le[i] != zero) { 279 *result = false; 280 break; 281 } 282 } 283 284 dm_bm_unlock(b); 285 286 return 0; 287 } 288 289 static void __setup_mapping_info(struct dm_cache_metadata *cmd) 290 { 291 struct dm_btree_value_type vt; 292 293 vt.context = NULL; 294 vt.size = sizeof(__le64); 295 vt.inc = NULL; 296 vt.dec = NULL; 297 vt.equal = NULL; 298 dm_array_info_init(&cmd->info, cmd->tm, &vt); 299 300 if (cmd->policy_hint_size) { 301 vt.size = sizeof(__le32); 302 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 303 } 304 } 305 306 static int __save_sm_root(struct dm_cache_metadata *cmd) 307 { 308 int r; 309 size_t metadata_len; 310 311 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 312 if (r < 0) 313 return r; 314 315 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, 316 metadata_len); 317 } 318 319 static void __copy_sm_root(struct dm_cache_metadata *cmd, 320 struct cache_disk_superblock *disk_super) 321 { 322 memcpy(&disk_super->metadata_space_map_root, 323 &cmd->metadata_space_map_root, 324 sizeof(cmd->metadata_space_map_root)); 325 } 326 327 static bool separate_dirty_bits(struct dm_cache_metadata *cmd) 328 { 329 return cmd->version >= 2; 330 } 331 332 static int __write_initial_superblock(struct dm_cache_metadata *cmd) 333 { 334 int r; 335 struct dm_block *sblock; 336 struct cache_disk_superblock *disk_super; 337 sector_t bdev_size = bdev_nr_sectors(cmd->bdev); 338 339 /* FIXME: see if we can lose the max sectors limit */ 340 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 341 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 342 343 r = dm_tm_pre_commit(cmd->tm); 344 if (r < 0) 345 return r; 346 347 /* 348 * dm_sm_copy_root() can fail. So we need to do it before we start 349 * updating the superblock. 350 */ 351 r = __save_sm_root(cmd); 352 if (r) 353 return r; 354 355 r = superblock_lock_zero(cmd, &sblock); 356 if (r) 357 return r; 358 359 disk_super = dm_block_data(sblock); 360 disk_super->flags = 0; 361 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 362 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 363 disk_super->version = cpu_to_le32(cmd->version); 364 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 365 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 366 disk_super->policy_hint_size = cpu_to_le32(0); 367 368 __copy_sm_root(cmd, disk_super); 369 370 disk_super->mapping_root = cpu_to_le64(cmd->root); 371 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 372 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 373 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 374 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 375 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE); 376 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 377 disk_super->cache_blocks = cpu_to_le32(0); 378 379 disk_super->read_hits = cpu_to_le32(0); 380 disk_super->read_misses = cpu_to_le32(0); 381 disk_super->write_hits = cpu_to_le32(0); 382 disk_super->write_misses = cpu_to_le32(0); 383 384 if (separate_dirty_bits(cmd)) 385 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 386 387 return dm_tm_commit(cmd->tm, sblock); 388 } 389 390 static int __format_metadata(struct dm_cache_metadata *cmd) 391 { 392 int r; 393 394 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 395 &cmd->tm, &cmd->metadata_sm); 396 if (r < 0) { 397 DMERR("tm_create_with_sm failed"); 398 return r; 399 } 400 401 __setup_mapping_info(cmd); 402 403 r = dm_array_empty(&cmd->info, &cmd->root); 404 if (r < 0) 405 goto bad; 406 407 if (separate_dirty_bits(cmd)) { 408 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 409 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root); 410 if (r < 0) 411 goto bad; 412 } 413 414 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 415 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 416 if (r < 0) 417 goto bad; 418 419 cmd->discard_block_size = 0; 420 cmd->discard_nr_blocks = 0; 421 422 r = __write_initial_superblock(cmd); 423 if (r) 424 goto bad; 425 426 cmd->clean_when_opened = true; 427 return 0; 428 429 bad: 430 dm_tm_destroy(cmd->tm); 431 dm_sm_destroy(cmd->metadata_sm); 432 433 return r; 434 } 435 436 static int __check_incompat_features(struct cache_disk_superblock *disk_super, 437 struct dm_cache_metadata *cmd) 438 { 439 uint32_t incompat_flags, features; 440 441 incompat_flags = le32_to_cpu(disk_super->incompat_flags); 442 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 443 if (features) { 444 DMERR("could not access metadata due to unsupported optional features (%lx).", 445 (unsigned long)features); 446 return -EINVAL; 447 } 448 449 /* 450 * Check for read-only metadata to skip the following RDWR checks. 451 */ 452 if (bdev_read_only(cmd->bdev)) 453 return 0; 454 455 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 456 if (features) { 457 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 458 (unsigned long)features); 459 return -EINVAL; 460 } 461 462 return 0; 463 } 464 465 static int __open_metadata(struct dm_cache_metadata *cmd) 466 { 467 int r; 468 struct dm_block *sblock; 469 struct cache_disk_superblock *disk_super; 470 unsigned long sb_flags; 471 472 r = superblock_read_lock(cmd, &sblock); 473 if (r < 0) { 474 DMERR("couldn't read lock superblock"); 475 return r; 476 } 477 478 disk_super = dm_block_data(sblock); 479 480 /* Verify the data block size hasn't changed */ 481 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) { 482 DMERR("changing the data block size (from %u to %llu) is not supported", 483 le32_to_cpu(disk_super->data_block_size), 484 (unsigned long long)cmd->data_block_size); 485 r = -EINVAL; 486 goto bad; 487 } 488 489 r = __check_incompat_features(disk_super, cmd); 490 if (r < 0) 491 goto bad; 492 493 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 494 disk_super->metadata_space_map_root, 495 sizeof(disk_super->metadata_space_map_root), 496 &cmd->tm, &cmd->metadata_sm); 497 if (r < 0) { 498 DMERR("tm_open_with_sm failed"); 499 goto bad; 500 } 501 502 __setup_mapping_info(cmd); 503 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 504 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 505 sb_flags = le32_to_cpu(disk_super->flags); 506 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 507 dm_bm_unlock(sblock); 508 509 return 0; 510 511 bad: 512 dm_bm_unlock(sblock); 513 return r; 514 } 515 516 static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 517 bool format_device) 518 { 519 int r; 520 bool unformatted = false; 521 522 r = __superblock_all_zeroes(cmd->bm, &unformatted); 523 if (r) 524 return r; 525 526 if (unformatted) 527 return format_device ? __format_metadata(cmd) : -EPERM; 528 529 return __open_metadata(cmd); 530 } 531 532 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 533 bool may_format_device) 534 { 535 int r; 536 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, 537 CACHE_MAX_CONCURRENT_LOCKS); 538 if (IS_ERR(cmd->bm)) { 539 DMERR("could not create block manager"); 540 r = PTR_ERR(cmd->bm); 541 cmd->bm = NULL; 542 return r; 543 } 544 545 r = __open_or_format_metadata(cmd, may_format_device); 546 if (r) { 547 dm_block_manager_destroy(cmd->bm); 548 cmd->bm = NULL; 549 } 550 551 return r; 552 } 553 554 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 555 { 556 dm_sm_destroy(cmd->metadata_sm); 557 dm_tm_destroy(cmd->tm); 558 dm_block_manager_destroy(cmd->bm); 559 } 560 561 typedef unsigned long (*flags_mutator)(unsigned long); 562 563 static void update_flags(struct cache_disk_superblock *disk_super, 564 flags_mutator mutator) 565 { 566 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 567 disk_super->flags = cpu_to_le32(sb_flags); 568 } 569 570 static unsigned long set_clean_shutdown(unsigned long flags) 571 { 572 set_bit(CLEAN_SHUTDOWN, &flags); 573 return flags; 574 } 575 576 static unsigned long clear_clean_shutdown(unsigned long flags) 577 { 578 clear_bit(CLEAN_SHUTDOWN, &flags); 579 return flags; 580 } 581 582 static void read_superblock_fields(struct dm_cache_metadata *cmd, 583 struct cache_disk_superblock *disk_super) 584 { 585 cmd->version = le32_to_cpu(disk_super->version); 586 cmd->flags = le32_to_cpu(disk_super->flags); 587 cmd->root = le64_to_cpu(disk_super->mapping_root); 588 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 589 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 590 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 591 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 592 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 593 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 594 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 595 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 596 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 597 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 598 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 599 600 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 601 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 602 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 603 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 604 605 if (separate_dirty_bits(cmd)) 606 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root); 607 608 cmd->changed = false; 609 } 610 611 /* 612 * The mutator updates the superblock flags. 613 */ 614 static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 615 flags_mutator mutator) 616 { 617 int r; 618 struct cache_disk_superblock *disk_super; 619 struct dm_block *sblock; 620 621 r = superblock_lock(cmd, &sblock); 622 if (r) 623 return r; 624 625 disk_super = dm_block_data(sblock); 626 update_flags(disk_super, mutator); 627 read_superblock_fields(cmd, disk_super); 628 dm_bm_unlock(sblock); 629 630 return dm_bm_flush(cmd->bm); 631 } 632 633 static int __begin_transaction(struct dm_cache_metadata *cmd) 634 { 635 int r; 636 struct cache_disk_superblock *disk_super; 637 struct dm_block *sblock; 638 639 /* 640 * We re-read the superblock every time. Shouldn't need to do this 641 * really. 642 */ 643 r = superblock_read_lock(cmd, &sblock); 644 if (r) 645 return r; 646 647 disk_super = dm_block_data(sblock); 648 read_superblock_fields(cmd, disk_super); 649 dm_bm_unlock(sblock); 650 651 return 0; 652 } 653 654 static int __commit_transaction(struct dm_cache_metadata *cmd, 655 flags_mutator mutator) 656 { 657 int r; 658 struct cache_disk_superblock *disk_super; 659 struct dm_block *sblock; 660 661 /* 662 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 663 */ 664 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 665 666 if (separate_dirty_bits(cmd)) { 667 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, 668 &cmd->dirty_root); 669 if (r) 670 return r; 671 } 672 673 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 674 &cmd->discard_root); 675 if (r) 676 return r; 677 678 r = dm_tm_pre_commit(cmd->tm); 679 if (r < 0) 680 return r; 681 682 r = __save_sm_root(cmd); 683 if (r) 684 return r; 685 686 r = superblock_lock(cmd, &sblock); 687 if (r) 688 return r; 689 690 disk_super = dm_block_data(sblock); 691 692 disk_super->flags = cpu_to_le32(cmd->flags); 693 if (mutator) 694 update_flags(disk_super, mutator); 695 696 disk_super->mapping_root = cpu_to_le64(cmd->root); 697 if (separate_dirty_bits(cmd)) 698 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 699 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 700 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 701 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 702 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 703 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 704 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 705 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 706 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 707 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 708 disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size); 709 710 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 711 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 712 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 713 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 714 __copy_sm_root(cmd, disk_super); 715 716 return dm_tm_commit(cmd->tm, sblock); 717 } 718 719 /*----------------------------------------------------------------*/ 720 721 /* 722 * The mappings are held in a dm-array that has 64-bit values stored in 723 * little-endian format. The index is the cblock, the high 48bits of the 724 * value are the oblock and the low 16 bit the flags. 725 */ 726 #define FLAGS_MASK ((1 << 16) - 1) 727 728 static __le64 pack_value(dm_oblock_t block, unsigned flags) 729 { 730 uint64_t value = from_oblock(block); 731 value <<= 16; 732 value = value | (flags & FLAGS_MASK); 733 return cpu_to_le64(value); 734 } 735 736 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 737 { 738 uint64_t value = le64_to_cpu(value_le); 739 uint64_t b = value >> 16; 740 *block = to_oblock(b); 741 *flags = value & FLAGS_MASK; 742 } 743 744 /*----------------------------------------------------------------*/ 745 746 static struct dm_cache_metadata *metadata_open(struct block_device *bdev, 747 sector_t data_block_size, 748 bool may_format_device, 749 size_t policy_hint_size, 750 unsigned metadata_version) 751 { 752 int r; 753 struct dm_cache_metadata *cmd; 754 755 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 756 if (!cmd) { 757 DMERR("could not allocate metadata struct"); 758 return ERR_PTR(-ENOMEM); 759 } 760 761 cmd->version = metadata_version; 762 refcount_set(&cmd->ref_count, 1); 763 init_rwsem(&cmd->root_lock); 764 cmd->bdev = bdev; 765 cmd->data_block_size = data_block_size; 766 cmd->cache_blocks = 0; 767 cmd->policy_hint_size = policy_hint_size; 768 cmd->changed = true; 769 cmd->fail_io = false; 770 771 r = __create_persistent_data_objects(cmd, may_format_device); 772 if (r) { 773 kfree(cmd); 774 return ERR_PTR(r); 775 } 776 777 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 778 if (r < 0) { 779 dm_cache_metadata_close(cmd); 780 return ERR_PTR(r); 781 } 782 783 return cmd; 784 } 785 786 /* 787 * We keep a little list of ref counted metadata objects to prevent two 788 * different target instances creating separate bufio instances. This is 789 * an issue if a table is reloaded before the suspend. 790 */ 791 static DEFINE_MUTEX(table_lock); 792 static LIST_HEAD(table); 793 794 static struct dm_cache_metadata *lookup(struct block_device *bdev) 795 { 796 struct dm_cache_metadata *cmd; 797 798 list_for_each_entry(cmd, &table, list) 799 if (cmd->bdev == bdev) { 800 refcount_inc(&cmd->ref_count); 801 return cmd; 802 } 803 804 return NULL; 805 } 806 807 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, 808 sector_t data_block_size, 809 bool may_format_device, 810 size_t policy_hint_size, 811 unsigned metadata_version) 812 { 813 struct dm_cache_metadata *cmd, *cmd2; 814 815 mutex_lock(&table_lock); 816 cmd = lookup(bdev); 817 mutex_unlock(&table_lock); 818 819 if (cmd) 820 return cmd; 821 822 cmd = metadata_open(bdev, data_block_size, may_format_device, 823 policy_hint_size, metadata_version); 824 if (!IS_ERR(cmd)) { 825 mutex_lock(&table_lock); 826 cmd2 = lookup(bdev); 827 if (cmd2) { 828 mutex_unlock(&table_lock); 829 __destroy_persistent_data_objects(cmd); 830 kfree(cmd); 831 return cmd2; 832 } 833 list_add(&cmd->list, &table); 834 mutex_unlock(&table_lock); 835 } 836 837 return cmd; 838 } 839 840 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) 841 { 842 if (cmd->data_block_size != data_block_size) { 843 DMERR("data_block_size (%llu) different from that in metadata (%llu)", 844 (unsigned long long) data_block_size, 845 (unsigned long long) cmd->data_block_size); 846 return false; 847 } 848 849 return true; 850 } 851 852 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 853 sector_t data_block_size, 854 bool may_format_device, 855 size_t policy_hint_size, 856 unsigned metadata_version) 857 { 858 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device, 859 policy_hint_size, metadata_version); 860 861 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { 862 dm_cache_metadata_close(cmd); 863 return ERR_PTR(-EINVAL); 864 } 865 866 return cmd; 867 } 868 869 void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 870 { 871 if (refcount_dec_and_test(&cmd->ref_count)) { 872 mutex_lock(&table_lock); 873 list_del(&cmd->list); 874 mutex_unlock(&table_lock); 875 876 if (!cmd->fail_io) 877 __destroy_persistent_data_objects(cmd); 878 kfree(cmd); 879 } 880 } 881 882 /* 883 * Checks that the given cache block is either unmapped or clean. 884 */ 885 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b, 886 bool *result) 887 { 888 int r; 889 __le64 value; 890 dm_oblock_t ob; 891 unsigned flags; 892 893 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 894 if (r) 895 return r; 896 897 unpack_value(value, &ob, &flags); 898 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 899 900 return 0; 901 } 902 903 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd, 904 dm_cblock_t begin, dm_cblock_t end, 905 bool *result) 906 { 907 int r; 908 *result = true; 909 910 while (begin != end) { 911 r = block_clean_combined_dirty(cmd, begin, result); 912 if (r) { 913 DMERR("block_clean_combined_dirty failed"); 914 return r; 915 } 916 917 if (!*result) { 918 DMERR("cache block %llu is dirty", 919 (unsigned long long) from_cblock(begin)); 920 return 0; 921 } 922 923 begin = to_cblock(from_cblock(begin) + 1); 924 } 925 926 return 0; 927 } 928 929 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, 930 dm_cblock_t begin, dm_cblock_t end, 931 bool *result) 932 { 933 int r; 934 bool dirty_flag; 935 *result = true; 936 937 if (from_cblock(cmd->cache_blocks) == 0) 938 /* Nothing to do */ 939 return 0; 940 941 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 942 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor); 943 if (r) { 944 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); 945 return r; 946 } 947 948 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin)); 949 if (r) { 950 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__); 951 dm_bitset_cursor_end(&cmd->dirty_cursor); 952 return r; 953 } 954 955 while (begin != end) { 956 /* 957 * We assume that unmapped blocks have their dirty bit 958 * cleared. 959 */ 960 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor); 961 if (dirty_flag) { 962 DMERR("%s: cache block %llu is dirty", __func__, 963 (unsigned long long) from_cblock(begin)); 964 dm_bitset_cursor_end(&cmd->dirty_cursor); 965 *result = false; 966 return 0; 967 } 968 969 begin = to_cblock(from_cblock(begin) + 1); 970 if (begin == end) 971 break; 972 973 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 974 if (r) { 975 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); 976 dm_bitset_cursor_end(&cmd->dirty_cursor); 977 return r; 978 } 979 } 980 981 dm_bitset_cursor_end(&cmd->dirty_cursor); 982 983 return 0; 984 } 985 986 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 987 dm_cblock_t begin, dm_cblock_t end, 988 bool *result) 989 { 990 if (separate_dirty_bits(cmd)) 991 return blocks_are_clean_separate_dirty(cmd, begin, end, result); 992 else 993 return blocks_are_clean_combined_dirty(cmd, begin, end, result); 994 } 995 996 static bool cmd_write_lock(struct dm_cache_metadata *cmd) 997 { 998 down_write(&cmd->root_lock); 999 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { 1000 up_write(&cmd->root_lock); 1001 return false; 1002 } 1003 return true; 1004 } 1005 1006 #define WRITE_LOCK(cmd) \ 1007 do { \ 1008 if (!cmd_write_lock((cmd))) \ 1009 return -EINVAL; \ 1010 } while(0) 1011 1012 #define WRITE_LOCK_VOID(cmd) \ 1013 do { \ 1014 if (!cmd_write_lock((cmd))) \ 1015 return; \ 1016 } while(0) 1017 1018 #define WRITE_UNLOCK(cmd) \ 1019 up_write(&(cmd)->root_lock) 1020 1021 static bool cmd_read_lock(struct dm_cache_metadata *cmd) 1022 { 1023 down_read(&cmd->root_lock); 1024 if (cmd->fail_io) { 1025 up_read(&cmd->root_lock); 1026 return false; 1027 } 1028 return true; 1029 } 1030 1031 #define READ_LOCK(cmd) \ 1032 do { \ 1033 if (!cmd_read_lock((cmd))) \ 1034 return -EINVAL; \ 1035 } while(0) 1036 1037 #define READ_LOCK_VOID(cmd) \ 1038 do { \ 1039 if (!cmd_read_lock((cmd))) \ 1040 return; \ 1041 } while(0) 1042 1043 #define READ_UNLOCK(cmd) \ 1044 up_read(&(cmd)->root_lock) 1045 1046 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 1047 { 1048 int r; 1049 bool clean; 1050 __le64 null_mapping = pack_value(0, 0); 1051 1052 WRITE_LOCK(cmd); 1053 __dm_bless_for_disk(&null_mapping); 1054 1055 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 1056 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 1057 if (r) { 1058 __dm_unbless_for_disk(&null_mapping); 1059 goto out; 1060 } 1061 1062 if (!clean) { 1063 DMERR("unable to shrink cache due to dirty blocks"); 1064 r = -EINVAL; 1065 __dm_unbless_for_disk(&null_mapping); 1066 goto out; 1067 } 1068 } 1069 1070 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 1071 from_cblock(new_cache_size), 1072 &null_mapping, &cmd->root); 1073 if (r) 1074 goto out; 1075 1076 if (separate_dirty_bits(cmd)) { 1077 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root, 1078 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size), 1079 false, &cmd->dirty_root); 1080 if (r) 1081 goto out; 1082 } 1083 1084 cmd->cache_blocks = new_cache_size; 1085 cmd->changed = true; 1086 1087 out: 1088 WRITE_UNLOCK(cmd); 1089 1090 return r; 1091 } 1092 1093 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 1094 sector_t discard_block_size, 1095 dm_dblock_t new_nr_entries) 1096 { 1097 int r; 1098 1099 WRITE_LOCK(cmd); 1100 r = dm_bitset_resize(&cmd->discard_info, 1101 cmd->discard_root, 1102 from_dblock(cmd->discard_nr_blocks), 1103 from_dblock(new_nr_entries), 1104 false, &cmd->discard_root); 1105 if (!r) { 1106 cmd->discard_block_size = discard_block_size; 1107 cmd->discard_nr_blocks = new_nr_entries; 1108 } 1109 1110 cmd->changed = true; 1111 WRITE_UNLOCK(cmd); 1112 1113 return r; 1114 } 1115 1116 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1117 { 1118 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 1119 from_dblock(b), &cmd->discard_root); 1120 } 1121 1122 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1123 { 1124 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 1125 from_dblock(b), &cmd->discard_root); 1126 } 1127 1128 static int __discard(struct dm_cache_metadata *cmd, 1129 dm_dblock_t dblock, bool discard) 1130 { 1131 int r; 1132 1133 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 1134 if (r) 1135 return r; 1136 1137 cmd->changed = true; 1138 return 0; 1139 } 1140 1141 int dm_cache_set_discard(struct dm_cache_metadata *cmd, 1142 dm_dblock_t dblock, bool discard) 1143 { 1144 int r; 1145 1146 WRITE_LOCK(cmd); 1147 r = __discard(cmd, dblock, discard); 1148 WRITE_UNLOCK(cmd); 1149 1150 return r; 1151 } 1152 1153 static int __load_discards(struct dm_cache_metadata *cmd, 1154 load_discard_fn fn, void *context) 1155 { 1156 int r = 0; 1157 uint32_t b; 1158 struct dm_bitset_cursor c; 1159 1160 if (from_dblock(cmd->discard_nr_blocks) == 0) 1161 /* nothing to do */ 1162 return 0; 1163 1164 if (cmd->clean_when_opened) { 1165 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root); 1166 if (r) 1167 return r; 1168 1169 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root, 1170 from_dblock(cmd->discard_nr_blocks), &c); 1171 if (r) 1172 return r; 1173 1174 for (b = 0; ; b++) { 1175 r = fn(context, cmd->discard_block_size, to_dblock(b), 1176 dm_bitset_cursor_get_value(&c)); 1177 if (r) 1178 break; 1179 1180 if (b >= (from_dblock(cmd->discard_nr_blocks) - 1)) 1181 break; 1182 1183 r = dm_bitset_cursor_next(&c); 1184 if (r) 1185 break; 1186 } 1187 1188 dm_bitset_cursor_end(&c); 1189 1190 } else { 1191 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1192 r = fn(context, cmd->discard_block_size, to_dblock(b), false); 1193 if (r) 1194 return r; 1195 } 1196 } 1197 1198 return r; 1199 } 1200 1201 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 1202 load_discard_fn fn, void *context) 1203 { 1204 int r; 1205 1206 READ_LOCK(cmd); 1207 r = __load_discards(cmd, fn, context); 1208 READ_UNLOCK(cmd); 1209 1210 return r; 1211 } 1212 1213 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result) 1214 { 1215 READ_LOCK(cmd); 1216 *result = cmd->cache_blocks; 1217 READ_UNLOCK(cmd); 1218 1219 return 0; 1220 } 1221 1222 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1223 { 1224 int r; 1225 __le64 value = pack_value(0, 0); 1226 1227 __dm_bless_for_disk(&value); 1228 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1229 &value, &cmd->root); 1230 if (r) 1231 return r; 1232 1233 cmd->changed = true; 1234 return 0; 1235 } 1236 1237 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1238 { 1239 int r; 1240 1241 WRITE_LOCK(cmd); 1242 r = __remove(cmd, cblock); 1243 WRITE_UNLOCK(cmd); 1244 1245 return r; 1246 } 1247 1248 static int __insert(struct dm_cache_metadata *cmd, 1249 dm_cblock_t cblock, dm_oblock_t oblock) 1250 { 1251 int r; 1252 __le64 value = pack_value(oblock, M_VALID); 1253 __dm_bless_for_disk(&value); 1254 1255 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1256 &value, &cmd->root); 1257 if (r) 1258 return r; 1259 1260 cmd->changed = true; 1261 return 0; 1262 } 1263 1264 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 1265 dm_cblock_t cblock, dm_oblock_t oblock) 1266 { 1267 int r; 1268 1269 WRITE_LOCK(cmd); 1270 r = __insert(cmd, cblock, oblock); 1271 WRITE_UNLOCK(cmd); 1272 1273 return r; 1274 } 1275 1276 struct thunk { 1277 load_mapping_fn fn; 1278 void *context; 1279 1280 struct dm_cache_metadata *cmd; 1281 bool respect_dirty_flags; 1282 bool hints_valid; 1283 }; 1284 1285 static bool policy_unchanged(struct dm_cache_metadata *cmd, 1286 struct dm_cache_policy *policy) 1287 { 1288 const char *policy_name = dm_cache_policy_get_name(policy); 1289 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1290 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 1291 1292 /* 1293 * Ensure policy names match. 1294 */ 1295 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 1296 return false; 1297 1298 /* 1299 * Ensure policy major versions match. 1300 */ 1301 if (cmd->policy_version[0] != policy_version[0]) 1302 return false; 1303 1304 /* 1305 * Ensure policy hint sizes match. 1306 */ 1307 if (cmd->policy_hint_size != policy_hint_size) 1308 return false; 1309 1310 return true; 1311 } 1312 1313 static bool hints_array_initialized(struct dm_cache_metadata *cmd) 1314 { 1315 return cmd->hint_root && cmd->policy_hint_size; 1316 } 1317 1318 static bool hints_array_available(struct dm_cache_metadata *cmd, 1319 struct dm_cache_policy *policy) 1320 { 1321 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 1322 hints_array_initialized(cmd); 1323 } 1324 1325 static int __load_mapping_v1(struct dm_cache_metadata *cmd, 1326 uint64_t cb, bool hints_valid, 1327 struct dm_array_cursor *mapping_cursor, 1328 struct dm_array_cursor *hint_cursor, 1329 load_mapping_fn fn, void *context) 1330 { 1331 int r = 0; 1332 1333 __le64 mapping; 1334 __le32 hint = 0; 1335 1336 __le64 *mapping_value_le; 1337 __le32 *hint_value_le; 1338 1339 dm_oblock_t oblock; 1340 unsigned flags; 1341 bool dirty = true; 1342 1343 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1344 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1345 unpack_value(mapping, &oblock, &flags); 1346 1347 if (flags & M_VALID) { 1348 if (hints_valid) { 1349 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1350 memcpy(&hint, hint_value_le, sizeof(hint)); 1351 } 1352 if (cmd->clean_when_opened) 1353 dirty = flags & M_DIRTY; 1354 1355 r = fn(context, oblock, to_cblock(cb), dirty, 1356 le32_to_cpu(hint), hints_valid); 1357 if (r) { 1358 DMERR("policy couldn't load cache block %llu", 1359 (unsigned long long) from_cblock(to_cblock(cb))); 1360 } 1361 } 1362 1363 return r; 1364 } 1365 1366 static int __load_mapping_v2(struct dm_cache_metadata *cmd, 1367 uint64_t cb, bool hints_valid, 1368 struct dm_array_cursor *mapping_cursor, 1369 struct dm_array_cursor *hint_cursor, 1370 struct dm_bitset_cursor *dirty_cursor, 1371 load_mapping_fn fn, void *context) 1372 { 1373 int r = 0; 1374 1375 __le64 mapping; 1376 __le32 hint = 0; 1377 1378 __le64 *mapping_value_le; 1379 __le32 *hint_value_le; 1380 1381 dm_oblock_t oblock; 1382 unsigned flags; 1383 bool dirty = true; 1384 1385 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1386 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1387 unpack_value(mapping, &oblock, &flags); 1388 1389 if (flags & M_VALID) { 1390 if (hints_valid) { 1391 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1392 memcpy(&hint, hint_value_le, sizeof(hint)); 1393 } 1394 if (cmd->clean_when_opened) 1395 dirty = dm_bitset_cursor_get_value(dirty_cursor); 1396 1397 r = fn(context, oblock, to_cblock(cb), dirty, 1398 le32_to_cpu(hint), hints_valid); 1399 if (r) { 1400 DMERR("policy couldn't load cache block %llu", 1401 (unsigned long long) from_cblock(to_cblock(cb))); 1402 } 1403 } 1404 1405 return r; 1406 } 1407 1408 static int __load_mappings(struct dm_cache_metadata *cmd, 1409 struct dm_cache_policy *policy, 1410 load_mapping_fn fn, void *context) 1411 { 1412 int r; 1413 uint64_t cb; 1414 1415 bool hints_valid = hints_array_available(cmd, policy); 1416 1417 if (from_cblock(cmd->cache_blocks) == 0) 1418 /* Nothing to do */ 1419 return 0; 1420 1421 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor); 1422 if (r) 1423 return r; 1424 1425 if (hints_valid) { 1426 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor); 1427 if (r) { 1428 dm_array_cursor_end(&cmd->mapping_cursor); 1429 return r; 1430 } 1431 } 1432 1433 if (separate_dirty_bits(cmd)) { 1434 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 1435 from_cblock(cmd->cache_blocks), 1436 &cmd->dirty_cursor); 1437 if (r) { 1438 dm_array_cursor_end(&cmd->hint_cursor); 1439 dm_array_cursor_end(&cmd->mapping_cursor); 1440 return r; 1441 } 1442 } 1443 1444 for (cb = 0; ; cb++) { 1445 if (separate_dirty_bits(cmd)) 1446 r = __load_mapping_v2(cmd, cb, hints_valid, 1447 &cmd->mapping_cursor, 1448 &cmd->hint_cursor, 1449 &cmd->dirty_cursor, 1450 fn, context); 1451 else 1452 r = __load_mapping_v1(cmd, cb, hints_valid, 1453 &cmd->mapping_cursor, &cmd->hint_cursor, 1454 fn, context); 1455 if (r) 1456 goto out; 1457 1458 /* 1459 * We need to break out before we move the cursors. 1460 */ 1461 if (cb >= (from_cblock(cmd->cache_blocks) - 1)) 1462 break; 1463 1464 r = dm_array_cursor_next(&cmd->mapping_cursor); 1465 if (r) { 1466 DMERR("dm_array_cursor_next for mapping failed"); 1467 goto out; 1468 } 1469 1470 if (hints_valid) { 1471 r = dm_array_cursor_next(&cmd->hint_cursor); 1472 if (r) { 1473 dm_array_cursor_end(&cmd->hint_cursor); 1474 hints_valid = false; 1475 } 1476 } 1477 1478 if (separate_dirty_bits(cmd)) { 1479 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 1480 if (r) { 1481 DMERR("dm_bitset_cursor_next for dirty failed"); 1482 goto out; 1483 } 1484 } 1485 } 1486 out: 1487 dm_array_cursor_end(&cmd->mapping_cursor); 1488 if (hints_valid) 1489 dm_array_cursor_end(&cmd->hint_cursor); 1490 1491 if (separate_dirty_bits(cmd)) 1492 dm_bitset_cursor_end(&cmd->dirty_cursor); 1493 1494 return r; 1495 } 1496 1497 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1498 struct dm_cache_policy *policy, 1499 load_mapping_fn fn, void *context) 1500 { 1501 int r; 1502 1503 READ_LOCK(cmd); 1504 r = __load_mappings(cmd, policy, fn, context); 1505 READ_UNLOCK(cmd); 1506 1507 return r; 1508 } 1509 1510 static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1511 { 1512 __le64 value; 1513 dm_oblock_t oblock; 1514 unsigned flags; 1515 1516 memcpy(&value, leaf, sizeof(value)); 1517 unpack_value(value, &oblock, &flags); 1518 1519 return 0; 1520 } 1521 1522 static int __dump_mappings(struct dm_cache_metadata *cmd) 1523 { 1524 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1525 } 1526 1527 void dm_cache_dump(struct dm_cache_metadata *cmd) 1528 { 1529 READ_LOCK_VOID(cmd); 1530 __dump_mappings(cmd); 1531 READ_UNLOCK(cmd); 1532 } 1533 1534 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1535 { 1536 int r; 1537 1538 READ_LOCK(cmd); 1539 r = cmd->changed; 1540 READ_UNLOCK(cmd); 1541 1542 return r; 1543 } 1544 1545 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1546 { 1547 int r; 1548 unsigned flags; 1549 dm_oblock_t oblock; 1550 __le64 value; 1551 1552 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1553 if (r) 1554 return r; 1555 1556 unpack_value(value, &oblock, &flags); 1557 1558 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1559 /* nothing to be done */ 1560 return 0; 1561 1562 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1563 __dm_bless_for_disk(&value); 1564 1565 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1566 &value, &cmd->root); 1567 if (r) 1568 return r; 1569 1570 cmd->changed = true; 1571 return 0; 1572 1573 } 1574 1575 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1576 { 1577 int r; 1578 unsigned i; 1579 for (i = 0; i < nr_bits; i++) { 1580 r = __dirty(cmd, to_cblock(i), test_bit(i, bits)); 1581 if (r) 1582 return r; 1583 } 1584 1585 return 0; 1586 } 1587 1588 static int is_dirty_callback(uint32_t index, bool *value, void *context) 1589 { 1590 unsigned long *bits = context; 1591 *value = test_bit(index, bits); 1592 return 0; 1593 } 1594 1595 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1596 { 1597 int r = 0; 1598 1599 /* nr_bits is really just a sanity check */ 1600 if (nr_bits != from_cblock(cmd->cache_blocks)) { 1601 DMERR("dirty bitset is wrong size"); 1602 return -EINVAL; 1603 } 1604 1605 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root); 1606 if (r) 1607 return r; 1608 1609 cmd->changed = true; 1610 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits); 1611 } 1612 1613 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, 1614 unsigned nr_bits, 1615 unsigned long *bits) 1616 { 1617 int r; 1618 1619 WRITE_LOCK(cmd); 1620 if (separate_dirty_bits(cmd)) 1621 r = __set_dirty_bits_v2(cmd, nr_bits, bits); 1622 else 1623 r = __set_dirty_bits_v1(cmd, nr_bits, bits); 1624 WRITE_UNLOCK(cmd); 1625 1626 return r; 1627 } 1628 1629 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1630 struct dm_cache_statistics *stats) 1631 { 1632 READ_LOCK_VOID(cmd); 1633 *stats = cmd->stats; 1634 READ_UNLOCK(cmd); 1635 } 1636 1637 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1638 struct dm_cache_statistics *stats) 1639 { 1640 WRITE_LOCK_VOID(cmd); 1641 cmd->stats = *stats; 1642 WRITE_UNLOCK(cmd); 1643 } 1644 1645 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1646 { 1647 int r = -EINVAL; 1648 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1649 clear_clean_shutdown); 1650 1651 WRITE_LOCK(cmd); 1652 if (cmd->fail_io) 1653 goto out; 1654 1655 r = __commit_transaction(cmd, mutator); 1656 if (r) 1657 goto out; 1658 1659 r = __begin_transaction(cmd); 1660 out: 1661 WRITE_UNLOCK(cmd); 1662 return r; 1663 } 1664 1665 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1666 dm_block_t *result) 1667 { 1668 int r = -EINVAL; 1669 1670 READ_LOCK(cmd); 1671 if (!cmd->fail_io) 1672 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1673 READ_UNLOCK(cmd); 1674 1675 return r; 1676 } 1677 1678 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1679 dm_block_t *result) 1680 { 1681 int r = -EINVAL; 1682 1683 READ_LOCK(cmd); 1684 if (!cmd->fail_io) 1685 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1686 READ_UNLOCK(cmd); 1687 1688 return r; 1689 } 1690 1691 /*----------------------------------------------------------------*/ 1692 1693 static int get_hint(uint32_t index, void *value_le, void *context) 1694 { 1695 uint32_t value; 1696 struct dm_cache_policy *policy = context; 1697 1698 value = policy_get_hint(policy, to_cblock(index)); 1699 *((__le32 *) value_le) = cpu_to_le32(value); 1700 1701 return 0; 1702 } 1703 1704 /* 1705 * It's quicker to always delete the hint array, and recreate with 1706 * dm_array_new(). 1707 */ 1708 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1709 { 1710 int r; 1711 size_t hint_size; 1712 const char *policy_name = dm_cache_policy_get_name(policy); 1713 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1714 1715 if (!policy_name[0] || 1716 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1717 return -EINVAL; 1718 1719 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1720 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1721 1722 hint_size = dm_cache_policy_get_hint_size(policy); 1723 if (!hint_size) 1724 return 0; /* short-circuit hints initialization */ 1725 cmd->policy_hint_size = hint_size; 1726 1727 if (cmd->hint_root) { 1728 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1729 if (r) 1730 return r; 1731 } 1732 1733 return dm_array_new(&cmd->hint_info, &cmd->hint_root, 1734 from_cblock(cmd->cache_blocks), 1735 get_hint, policy); 1736 } 1737 1738 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1739 { 1740 int r; 1741 1742 WRITE_LOCK(cmd); 1743 r = write_hints(cmd, policy); 1744 WRITE_UNLOCK(cmd); 1745 1746 return r; 1747 } 1748 1749 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1750 { 1751 int r; 1752 1753 READ_LOCK(cmd); 1754 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1755 READ_UNLOCK(cmd); 1756 1757 return r; 1758 } 1759 1760 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) 1761 { 1762 WRITE_LOCK_VOID(cmd); 1763 dm_bm_set_read_only(cmd->bm); 1764 WRITE_UNLOCK(cmd); 1765 } 1766 1767 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) 1768 { 1769 WRITE_LOCK_VOID(cmd); 1770 dm_bm_set_read_write(cmd->bm); 1771 WRITE_UNLOCK(cmd); 1772 } 1773 1774 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) 1775 { 1776 int r; 1777 struct dm_block *sblock; 1778 struct cache_disk_superblock *disk_super; 1779 1780 WRITE_LOCK(cmd); 1781 set_bit(NEEDS_CHECK, &cmd->flags); 1782 1783 r = superblock_lock(cmd, &sblock); 1784 if (r) { 1785 DMERR("couldn't read superblock"); 1786 goto out; 1787 } 1788 1789 disk_super = dm_block_data(sblock); 1790 disk_super->flags = cpu_to_le32(cmd->flags); 1791 1792 dm_bm_unlock(sblock); 1793 1794 out: 1795 WRITE_UNLOCK(cmd); 1796 return r; 1797 } 1798 1799 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) 1800 { 1801 READ_LOCK(cmd); 1802 *result = !!test_bit(NEEDS_CHECK, &cmd->flags); 1803 READ_UNLOCK(cmd); 1804 1805 return 0; 1806 } 1807 1808 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) 1809 { 1810 int r; 1811 1812 WRITE_LOCK(cmd); 1813 __destroy_persistent_data_objects(cmd); 1814 r = __create_persistent_data_objects(cmd, false); 1815 if (r) 1816 cmd->fail_io = true; 1817 WRITE_UNLOCK(cmd); 1818 1819 return r; 1820 } 1821