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 2 29 30 /* 31 * 3 for btree insert + 32 * 2 for btree lookup used within space map 33 */ 34 #define CACHE_MAX_CONCURRENT_LOCKS 5 35 #define SPACE_MAP_ROOT_SIZE 128 36 37 enum superblock_flag_bits { 38 /* for spotting crashes that would invalidate the dirty bitset */ 39 CLEAN_SHUTDOWN, 40 /* metadata must be checked using the tools */ 41 NEEDS_CHECK, 42 }; 43 44 /* 45 * Each mapping from cache block -> origin block carries a set of flags. 46 */ 47 enum mapping_bits { 48 /* 49 * A valid mapping. Because we're using an array we clear this 50 * flag for an non existant mapping. 51 */ 52 M_VALID = 1, 53 54 /* 55 * The data on the cache is different from that on the origin. 56 * This flag is only used by metadata format 1. 57 */ 58 M_DIRTY = 2 59 }; 60 61 struct cache_disk_superblock { 62 __le32 csum; 63 __le32 flags; 64 __le64 blocknr; 65 66 __u8 uuid[16]; 67 __le64 magic; 68 __le32 version; 69 70 __u8 policy_name[CACHE_POLICY_NAME_SIZE]; 71 __le32 policy_hint_size; 72 73 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 74 __le64 mapping_root; 75 __le64 hint_root; 76 77 __le64 discard_root; 78 __le64 discard_block_size; 79 __le64 discard_nr_blocks; 80 81 __le32 data_block_size; 82 __le32 metadata_block_size; 83 __le32 cache_blocks; 84 85 __le32 compat_flags; 86 __le32 compat_ro_flags; 87 __le32 incompat_flags; 88 89 __le32 read_hits; 90 __le32 read_misses; 91 __le32 write_hits; 92 __le32 write_misses; 93 94 __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; 95 96 /* 97 * Metadata format 2 fields. 98 */ 99 __le64 dirty_root; 100 } __packed; 101 102 struct dm_cache_metadata { 103 atomic_t ref_count; 104 struct list_head list; 105 106 unsigned version; 107 struct block_device *bdev; 108 struct dm_block_manager *bm; 109 struct dm_space_map *metadata_sm; 110 struct dm_transaction_manager *tm; 111 112 struct dm_array_info info; 113 struct dm_array_info hint_info; 114 struct dm_disk_bitset discard_info; 115 116 struct rw_semaphore root_lock; 117 unsigned long flags; 118 dm_block_t root; 119 dm_block_t hint_root; 120 dm_block_t discard_root; 121 122 sector_t discard_block_size; 123 dm_dblock_t discard_nr_blocks; 124 125 sector_t data_block_size; 126 dm_cblock_t cache_blocks; 127 bool changed:1; 128 bool clean_when_opened:1; 129 130 char policy_name[CACHE_POLICY_NAME_SIZE]; 131 unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; 132 size_t policy_hint_size; 133 struct dm_cache_statistics stats; 134 135 /* 136 * Reading the space map root can fail, so we read it into this 137 * buffer before the superblock is locked and updated. 138 */ 139 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 140 141 /* 142 * Set if a transaction has to be aborted but the attempt to roll 143 * back to the previous (good) transaction failed. The only 144 * metadata operation permissible in this state is the closing of 145 * the device. 146 */ 147 bool fail_io:1; 148 149 /* 150 * Metadata format 2 fields. 151 */ 152 dm_block_t dirty_root; 153 struct dm_disk_bitset dirty_info; 154 155 /* 156 * These structures are used when loading metadata. They're too 157 * big to put on the stack. 158 */ 159 struct dm_array_cursor mapping_cursor; 160 struct dm_array_cursor hint_cursor; 161 struct dm_bitset_cursor dirty_cursor; 162 }; 163 164 /*------------------------------------------------------------------- 165 * superblock validator 166 *-----------------------------------------------------------------*/ 167 168 #define SUPERBLOCK_CSUM_XOR 9031977 169 170 static void sb_prepare_for_write(struct dm_block_validator *v, 171 struct dm_block *b, 172 size_t sb_block_size) 173 { 174 struct cache_disk_superblock *disk_super = dm_block_data(b); 175 176 disk_super->blocknr = cpu_to_le64(dm_block_location(b)); 177 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 178 sb_block_size - sizeof(__le32), 179 SUPERBLOCK_CSUM_XOR)); 180 } 181 182 static int check_metadata_version(struct cache_disk_superblock *disk_super) 183 { 184 uint32_t metadata_version = le32_to_cpu(disk_super->version); 185 186 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { 187 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", 188 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); 189 return -EINVAL; 190 } 191 192 return 0; 193 } 194 195 static int sb_check(struct dm_block_validator *v, 196 struct dm_block *b, 197 size_t sb_block_size) 198 { 199 struct cache_disk_superblock *disk_super = dm_block_data(b); 200 __le32 csum_le; 201 202 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { 203 DMERR("sb_check failed: blocknr %llu: wanted %llu", 204 le64_to_cpu(disk_super->blocknr), 205 (unsigned long long)dm_block_location(b)); 206 return -ENOTBLK; 207 } 208 209 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { 210 DMERR("sb_check failed: magic %llu: wanted %llu", 211 le64_to_cpu(disk_super->magic), 212 (unsigned long long)CACHE_SUPERBLOCK_MAGIC); 213 return -EILSEQ; 214 } 215 216 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, 217 sb_block_size - sizeof(__le32), 218 SUPERBLOCK_CSUM_XOR)); 219 if (csum_le != disk_super->csum) { 220 DMERR("sb_check failed: csum %u: wanted %u", 221 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); 222 return -EILSEQ; 223 } 224 225 return check_metadata_version(disk_super); 226 } 227 228 static struct dm_block_validator sb_validator = { 229 .name = "superblock", 230 .prepare_for_write = sb_prepare_for_write, 231 .check = sb_check 232 }; 233 234 /*----------------------------------------------------------------*/ 235 236 static int superblock_read_lock(struct dm_cache_metadata *cmd, 237 struct dm_block **sblock) 238 { 239 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 240 &sb_validator, sblock); 241 } 242 243 static int superblock_lock_zero(struct dm_cache_metadata *cmd, 244 struct dm_block **sblock) 245 { 246 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 247 &sb_validator, sblock); 248 } 249 250 static int superblock_lock(struct dm_cache_metadata *cmd, 251 struct dm_block **sblock) 252 { 253 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 254 &sb_validator, sblock); 255 } 256 257 /*----------------------------------------------------------------*/ 258 259 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 260 { 261 int r; 262 unsigned i; 263 struct dm_block *b; 264 __le64 *data_le, zero = cpu_to_le64(0); 265 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 266 267 /* 268 * We can't use a validator here - it may be all zeroes. 269 */ 270 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); 271 if (r) 272 return r; 273 274 data_le = dm_block_data(b); 275 *result = true; 276 for (i = 0; i < sb_block_size; i++) { 277 if (data_le[i] != zero) { 278 *result = false; 279 break; 280 } 281 } 282 283 dm_bm_unlock(b); 284 285 return 0; 286 } 287 288 static void __setup_mapping_info(struct dm_cache_metadata *cmd) 289 { 290 struct dm_btree_value_type vt; 291 292 vt.context = NULL; 293 vt.size = sizeof(__le64); 294 vt.inc = NULL; 295 vt.dec = NULL; 296 vt.equal = NULL; 297 dm_array_info_init(&cmd->info, cmd->tm, &vt); 298 299 if (cmd->policy_hint_size) { 300 vt.size = sizeof(__le32); 301 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); 302 } 303 } 304 305 static int __save_sm_root(struct dm_cache_metadata *cmd) 306 { 307 int r; 308 size_t metadata_len; 309 310 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); 311 if (r < 0) 312 return r; 313 314 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, 315 metadata_len); 316 } 317 318 static void __copy_sm_root(struct dm_cache_metadata *cmd, 319 struct cache_disk_superblock *disk_super) 320 { 321 memcpy(&disk_super->metadata_space_map_root, 322 &cmd->metadata_space_map_root, 323 sizeof(cmd->metadata_space_map_root)); 324 } 325 326 static bool separate_dirty_bits(struct dm_cache_metadata *cmd) 327 { 328 return cmd->version >= 2; 329 } 330 331 static int __write_initial_superblock(struct dm_cache_metadata *cmd) 332 { 333 int r; 334 struct dm_block *sblock; 335 struct cache_disk_superblock *disk_super; 336 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; 337 338 /* FIXME: see if we can lose the max sectors limit */ 339 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) 340 bdev_size = DM_CACHE_METADATA_MAX_SECTORS; 341 342 r = dm_tm_pre_commit(cmd->tm); 343 if (r < 0) 344 return r; 345 346 /* 347 * dm_sm_copy_root() can fail. So we need to do it before we start 348 * updating the superblock. 349 */ 350 r = __save_sm_root(cmd); 351 if (r) 352 return r; 353 354 r = superblock_lock_zero(cmd, &sblock); 355 if (r) 356 return r; 357 358 disk_super = dm_block_data(sblock); 359 disk_super->flags = 0; 360 memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); 361 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); 362 disk_super->version = cpu_to_le32(cmd->version); 363 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); 364 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); 365 disk_super->policy_hint_size = 0; 366 367 __copy_sm_root(cmd, disk_super); 368 369 disk_super->mapping_root = cpu_to_le64(cmd->root); 370 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 371 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 372 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 373 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 374 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE); 375 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); 376 disk_super->cache_blocks = cpu_to_le32(0); 377 378 disk_super->read_hits = cpu_to_le32(0); 379 disk_super->read_misses = cpu_to_le32(0); 380 disk_super->write_hits = cpu_to_le32(0); 381 disk_super->write_misses = cpu_to_le32(0); 382 383 if (separate_dirty_bits(cmd)) 384 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 385 386 return dm_tm_commit(cmd->tm, sblock); 387 } 388 389 static int __format_metadata(struct dm_cache_metadata *cmd) 390 { 391 int r; 392 393 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 394 &cmd->tm, &cmd->metadata_sm); 395 if (r < 0) { 396 DMERR("tm_create_with_sm failed"); 397 return r; 398 } 399 400 __setup_mapping_info(cmd); 401 402 r = dm_array_empty(&cmd->info, &cmd->root); 403 if (r < 0) 404 goto bad; 405 406 if (separate_dirty_bits(cmd)) { 407 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 408 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root); 409 if (r < 0) 410 goto bad; 411 } 412 413 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 414 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); 415 if (r < 0) 416 goto bad; 417 418 cmd->discard_block_size = 0; 419 cmd->discard_nr_blocks = 0; 420 421 r = __write_initial_superblock(cmd); 422 if (r) 423 goto bad; 424 425 cmd->clean_when_opened = true; 426 return 0; 427 428 bad: 429 dm_tm_destroy(cmd->tm); 430 dm_sm_destroy(cmd->metadata_sm); 431 432 return r; 433 } 434 435 static int __check_incompat_features(struct cache_disk_superblock *disk_super, 436 struct dm_cache_metadata *cmd) 437 { 438 uint32_t incompat_flags, features; 439 440 incompat_flags = le32_to_cpu(disk_super->incompat_flags); 441 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; 442 if (features) { 443 DMERR("could not access metadata due to unsupported optional features (%lx).", 444 (unsigned long)features); 445 return -EINVAL; 446 } 447 448 /* 449 * Check for read-only metadata to skip the following RDWR checks. 450 */ 451 if (get_disk_ro(cmd->bdev->bd_disk)) 452 return 0; 453 454 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; 455 if (features) { 456 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", 457 (unsigned long)features); 458 return -EINVAL; 459 } 460 461 return 0; 462 } 463 464 static int __open_metadata(struct dm_cache_metadata *cmd) 465 { 466 int r; 467 struct dm_block *sblock; 468 struct cache_disk_superblock *disk_super; 469 unsigned long sb_flags; 470 471 r = superblock_read_lock(cmd, &sblock); 472 if (r < 0) { 473 DMERR("couldn't read lock superblock"); 474 return r; 475 } 476 477 disk_super = dm_block_data(sblock); 478 479 /* Verify the data block size hasn't changed */ 480 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) { 481 DMERR("changing the data block size (from %u to %llu) is not supported", 482 le32_to_cpu(disk_super->data_block_size), 483 (unsigned long long)cmd->data_block_size); 484 r = -EINVAL; 485 goto bad; 486 } 487 488 r = __check_incompat_features(disk_super, cmd); 489 if (r < 0) 490 goto bad; 491 492 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 493 disk_super->metadata_space_map_root, 494 sizeof(disk_super->metadata_space_map_root), 495 &cmd->tm, &cmd->metadata_sm); 496 if (r < 0) { 497 DMERR("tm_open_with_sm failed"); 498 goto bad; 499 } 500 501 __setup_mapping_info(cmd); 502 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); 503 dm_disk_bitset_init(cmd->tm, &cmd->discard_info); 504 sb_flags = le32_to_cpu(disk_super->flags); 505 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); 506 dm_bm_unlock(sblock); 507 508 return 0; 509 510 bad: 511 dm_bm_unlock(sblock); 512 return r; 513 } 514 515 static int __open_or_format_metadata(struct dm_cache_metadata *cmd, 516 bool format_device) 517 { 518 int r; 519 bool unformatted = false; 520 521 r = __superblock_all_zeroes(cmd->bm, &unformatted); 522 if (r) 523 return r; 524 525 if (unformatted) 526 return format_device ? __format_metadata(cmd) : -EPERM; 527 528 return __open_metadata(cmd); 529 } 530 531 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, 532 bool may_format_device) 533 { 534 int r; 535 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, 536 CACHE_MAX_CONCURRENT_LOCKS); 537 if (IS_ERR(cmd->bm)) { 538 DMERR("could not create block manager"); 539 return PTR_ERR(cmd->bm); 540 } 541 542 r = __open_or_format_metadata(cmd, may_format_device); 543 if (r) 544 dm_block_manager_destroy(cmd->bm); 545 546 return r; 547 } 548 549 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) 550 { 551 dm_sm_destroy(cmd->metadata_sm); 552 dm_tm_destroy(cmd->tm); 553 dm_block_manager_destroy(cmd->bm); 554 } 555 556 typedef unsigned long (*flags_mutator)(unsigned long); 557 558 static void update_flags(struct cache_disk_superblock *disk_super, 559 flags_mutator mutator) 560 { 561 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); 562 disk_super->flags = cpu_to_le32(sb_flags); 563 } 564 565 static unsigned long set_clean_shutdown(unsigned long flags) 566 { 567 set_bit(CLEAN_SHUTDOWN, &flags); 568 return flags; 569 } 570 571 static unsigned long clear_clean_shutdown(unsigned long flags) 572 { 573 clear_bit(CLEAN_SHUTDOWN, &flags); 574 return flags; 575 } 576 577 static void read_superblock_fields(struct dm_cache_metadata *cmd, 578 struct cache_disk_superblock *disk_super) 579 { 580 cmd->version = le32_to_cpu(disk_super->version); 581 cmd->flags = le32_to_cpu(disk_super->flags); 582 cmd->root = le64_to_cpu(disk_super->mapping_root); 583 cmd->hint_root = le64_to_cpu(disk_super->hint_root); 584 cmd->discard_root = le64_to_cpu(disk_super->discard_root); 585 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); 586 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); 587 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); 588 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); 589 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); 590 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); 591 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); 592 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); 593 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); 594 595 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); 596 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); 597 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); 598 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); 599 600 if (separate_dirty_bits(cmd)) 601 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root); 602 603 cmd->changed = false; 604 } 605 606 /* 607 * The mutator updates the superblock flags. 608 */ 609 static int __begin_transaction_flags(struct dm_cache_metadata *cmd, 610 flags_mutator mutator) 611 { 612 int r; 613 struct cache_disk_superblock *disk_super; 614 struct dm_block *sblock; 615 616 r = superblock_lock(cmd, &sblock); 617 if (r) 618 return r; 619 620 disk_super = dm_block_data(sblock); 621 update_flags(disk_super, mutator); 622 read_superblock_fields(cmd, disk_super); 623 dm_bm_unlock(sblock); 624 625 return dm_bm_flush(cmd->bm); 626 } 627 628 static int __begin_transaction(struct dm_cache_metadata *cmd) 629 { 630 int r; 631 struct cache_disk_superblock *disk_super; 632 struct dm_block *sblock; 633 634 /* 635 * We re-read the superblock every time. Shouldn't need to do this 636 * really. 637 */ 638 r = superblock_read_lock(cmd, &sblock); 639 if (r) 640 return r; 641 642 disk_super = dm_block_data(sblock); 643 read_superblock_fields(cmd, disk_super); 644 dm_bm_unlock(sblock); 645 646 return 0; 647 } 648 649 static int __commit_transaction(struct dm_cache_metadata *cmd, 650 flags_mutator mutator) 651 { 652 int r; 653 struct cache_disk_superblock *disk_super; 654 struct dm_block *sblock; 655 656 /* 657 * We need to know if the cache_disk_superblock exceeds a 512-byte sector. 658 */ 659 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); 660 661 if (separate_dirty_bits(cmd)) { 662 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, 663 &cmd->dirty_root); 664 if (r) 665 return r; 666 } 667 668 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, 669 &cmd->discard_root); 670 if (r) 671 return r; 672 673 r = dm_tm_pre_commit(cmd->tm); 674 if (r < 0) 675 return r; 676 677 r = __save_sm_root(cmd); 678 if (r) 679 return r; 680 681 r = superblock_lock(cmd, &sblock); 682 if (r) 683 return r; 684 685 disk_super = dm_block_data(sblock); 686 687 disk_super->flags = cpu_to_le32(cmd->flags); 688 if (mutator) 689 update_flags(disk_super, mutator); 690 691 disk_super->mapping_root = cpu_to_le64(cmd->root); 692 if (separate_dirty_bits(cmd)) 693 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); 694 disk_super->hint_root = cpu_to_le64(cmd->hint_root); 695 disk_super->discard_root = cpu_to_le64(cmd->discard_root); 696 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); 697 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); 698 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); 699 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); 700 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); 701 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); 702 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); 703 704 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); 705 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); 706 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); 707 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); 708 __copy_sm_root(cmd, disk_super); 709 710 return dm_tm_commit(cmd->tm, sblock); 711 } 712 713 /*----------------------------------------------------------------*/ 714 715 /* 716 * The mappings are held in a dm-array that has 64-bit values stored in 717 * little-endian format. The index is the cblock, the high 48bits of the 718 * value are the oblock and the low 16 bit the flags. 719 */ 720 #define FLAGS_MASK ((1 << 16) - 1) 721 722 static __le64 pack_value(dm_oblock_t block, unsigned flags) 723 { 724 uint64_t value = from_oblock(block); 725 value <<= 16; 726 value = value | (flags & FLAGS_MASK); 727 return cpu_to_le64(value); 728 } 729 730 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 731 { 732 uint64_t value = le64_to_cpu(value_le); 733 uint64_t b = value >> 16; 734 *block = to_oblock(b); 735 *flags = value & FLAGS_MASK; 736 } 737 738 /*----------------------------------------------------------------*/ 739 740 static struct dm_cache_metadata *metadata_open(struct block_device *bdev, 741 sector_t data_block_size, 742 bool may_format_device, 743 size_t policy_hint_size, 744 unsigned metadata_version) 745 { 746 int r; 747 struct dm_cache_metadata *cmd; 748 749 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); 750 if (!cmd) { 751 DMERR("could not allocate metadata struct"); 752 return ERR_PTR(-ENOMEM); 753 } 754 755 cmd->version = metadata_version; 756 atomic_set(&cmd->ref_count, 1); 757 init_rwsem(&cmd->root_lock); 758 cmd->bdev = bdev; 759 cmd->data_block_size = data_block_size; 760 cmd->cache_blocks = 0; 761 cmd->policy_hint_size = policy_hint_size; 762 cmd->changed = true; 763 cmd->fail_io = false; 764 765 r = __create_persistent_data_objects(cmd, may_format_device); 766 if (r) { 767 kfree(cmd); 768 return ERR_PTR(r); 769 } 770 771 r = __begin_transaction_flags(cmd, clear_clean_shutdown); 772 if (r < 0) { 773 dm_cache_metadata_close(cmd); 774 return ERR_PTR(r); 775 } 776 777 return cmd; 778 } 779 780 /* 781 * We keep a little list of ref counted metadata objects to prevent two 782 * different target instances creating separate bufio instances. This is 783 * an issue if a table is reloaded before the suspend. 784 */ 785 static DEFINE_MUTEX(table_lock); 786 static LIST_HEAD(table); 787 788 static struct dm_cache_metadata *lookup(struct block_device *bdev) 789 { 790 struct dm_cache_metadata *cmd; 791 792 list_for_each_entry(cmd, &table, list) 793 if (cmd->bdev == bdev) { 794 atomic_inc(&cmd->ref_count); 795 return cmd; 796 } 797 798 return NULL; 799 } 800 801 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, 802 sector_t data_block_size, 803 bool may_format_device, 804 size_t policy_hint_size, 805 unsigned metadata_version) 806 { 807 struct dm_cache_metadata *cmd, *cmd2; 808 809 mutex_lock(&table_lock); 810 cmd = lookup(bdev); 811 mutex_unlock(&table_lock); 812 813 if (cmd) 814 return cmd; 815 816 cmd = metadata_open(bdev, data_block_size, may_format_device, 817 policy_hint_size, metadata_version); 818 if (!IS_ERR(cmd)) { 819 mutex_lock(&table_lock); 820 cmd2 = lookup(bdev); 821 if (cmd2) { 822 mutex_unlock(&table_lock); 823 __destroy_persistent_data_objects(cmd); 824 kfree(cmd); 825 return cmd2; 826 } 827 list_add(&cmd->list, &table); 828 mutex_unlock(&table_lock); 829 } 830 831 return cmd; 832 } 833 834 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) 835 { 836 if (cmd->data_block_size != data_block_size) { 837 DMERR("data_block_size (%llu) different from that in metadata (%llu)", 838 (unsigned long long) data_block_size, 839 (unsigned long long) cmd->data_block_size); 840 return false; 841 } 842 843 return true; 844 } 845 846 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 847 sector_t data_block_size, 848 bool may_format_device, 849 size_t policy_hint_size, 850 unsigned metadata_version) 851 { 852 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device, 853 policy_hint_size, metadata_version); 854 855 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { 856 dm_cache_metadata_close(cmd); 857 return ERR_PTR(-EINVAL); 858 } 859 860 return cmd; 861 } 862 863 void dm_cache_metadata_close(struct dm_cache_metadata *cmd) 864 { 865 if (atomic_dec_and_test(&cmd->ref_count)) { 866 mutex_lock(&table_lock); 867 list_del(&cmd->list); 868 mutex_unlock(&table_lock); 869 870 if (!cmd->fail_io) 871 __destroy_persistent_data_objects(cmd); 872 kfree(cmd); 873 } 874 } 875 876 /* 877 * Checks that the given cache block is either unmapped or clean. 878 */ 879 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b, 880 bool *result) 881 { 882 int r; 883 __le64 value; 884 dm_oblock_t ob; 885 unsigned flags; 886 887 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); 888 if (r) 889 return r; 890 891 unpack_value(value, &ob, &flags); 892 *result = !((flags & M_VALID) && (flags & M_DIRTY)); 893 894 return 0; 895 } 896 897 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd, 898 dm_cblock_t begin, dm_cblock_t end, 899 bool *result) 900 { 901 int r; 902 *result = true; 903 904 while (begin != end) { 905 r = block_clean_combined_dirty(cmd, begin, result); 906 if (r) { 907 DMERR("block_clean_combined_dirty failed"); 908 return r; 909 } 910 911 if (!*result) { 912 DMERR("cache block %llu is dirty", 913 (unsigned long long) from_cblock(begin)); 914 return 0; 915 } 916 917 begin = to_cblock(from_cblock(begin) + 1); 918 } 919 920 return 0; 921 } 922 923 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, 924 dm_cblock_t begin, dm_cblock_t end, 925 bool *result) 926 { 927 int r; 928 bool dirty_flag; 929 *result = true; 930 931 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 932 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor); 933 if (r) { 934 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); 935 return r; 936 } 937 938 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin)); 939 if (r) { 940 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__); 941 dm_bitset_cursor_end(&cmd->dirty_cursor); 942 return r; 943 } 944 945 while (begin != end) { 946 /* 947 * We assume that unmapped blocks have their dirty bit 948 * cleared. 949 */ 950 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor); 951 if (dirty_flag) { 952 DMERR("%s: cache block %llu is dirty", __func__, 953 (unsigned long long) from_cblock(begin)); 954 dm_bitset_cursor_end(&cmd->dirty_cursor); 955 *result = false; 956 return 0; 957 } 958 959 begin = to_cblock(from_cblock(begin) + 1); 960 if (begin == end) 961 break; 962 963 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 964 if (r) { 965 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); 966 dm_bitset_cursor_end(&cmd->dirty_cursor); 967 return r; 968 } 969 } 970 971 dm_bitset_cursor_end(&cmd->dirty_cursor); 972 973 return 0; 974 } 975 976 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, 977 dm_cblock_t begin, dm_cblock_t end, 978 bool *result) 979 { 980 if (separate_dirty_bits(cmd)) 981 return blocks_are_clean_separate_dirty(cmd, begin, end, result); 982 else 983 return blocks_are_clean_combined_dirty(cmd, begin, end, result); 984 } 985 986 static bool cmd_write_lock(struct dm_cache_metadata *cmd) 987 { 988 down_write(&cmd->root_lock); 989 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { 990 up_write(&cmd->root_lock); 991 return false; 992 } 993 return true; 994 } 995 996 #define WRITE_LOCK(cmd) \ 997 do { \ 998 if (!cmd_write_lock((cmd))) \ 999 return -EINVAL; \ 1000 } while(0) 1001 1002 #define WRITE_LOCK_VOID(cmd) \ 1003 do { \ 1004 if (!cmd_write_lock((cmd))) \ 1005 return; \ 1006 } while(0) 1007 1008 #define WRITE_UNLOCK(cmd) \ 1009 up_write(&(cmd)->root_lock) 1010 1011 static bool cmd_read_lock(struct dm_cache_metadata *cmd) 1012 { 1013 down_read(&cmd->root_lock); 1014 if (cmd->fail_io) { 1015 up_read(&cmd->root_lock); 1016 return false; 1017 } 1018 return true; 1019 } 1020 1021 #define READ_LOCK(cmd) \ 1022 do { \ 1023 if (!cmd_read_lock((cmd))) \ 1024 return -EINVAL; \ 1025 } while(0) 1026 1027 #define READ_LOCK_VOID(cmd) \ 1028 do { \ 1029 if (!cmd_read_lock((cmd))) \ 1030 return; \ 1031 } while(0) 1032 1033 #define READ_UNLOCK(cmd) \ 1034 up_read(&(cmd)->root_lock) 1035 1036 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) 1037 { 1038 int r; 1039 bool clean; 1040 __le64 null_mapping = pack_value(0, 0); 1041 1042 WRITE_LOCK(cmd); 1043 __dm_bless_for_disk(&null_mapping); 1044 1045 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { 1046 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); 1047 if (r) { 1048 __dm_unbless_for_disk(&null_mapping); 1049 goto out; 1050 } 1051 1052 if (!clean) { 1053 DMERR("unable to shrink cache due to dirty blocks"); 1054 r = -EINVAL; 1055 __dm_unbless_for_disk(&null_mapping); 1056 goto out; 1057 } 1058 } 1059 1060 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), 1061 from_cblock(new_cache_size), 1062 &null_mapping, &cmd->root); 1063 if (r) 1064 goto out; 1065 1066 if (separate_dirty_bits(cmd)) { 1067 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root, 1068 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size), 1069 false, &cmd->dirty_root); 1070 if (r) 1071 goto out; 1072 } 1073 1074 cmd->cache_blocks = new_cache_size; 1075 cmd->changed = true; 1076 1077 out: 1078 WRITE_UNLOCK(cmd); 1079 1080 return r; 1081 } 1082 1083 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, 1084 sector_t discard_block_size, 1085 dm_dblock_t new_nr_entries) 1086 { 1087 int r; 1088 1089 WRITE_LOCK(cmd); 1090 r = dm_bitset_resize(&cmd->discard_info, 1091 cmd->discard_root, 1092 from_dblock(cmd->discard_nr_blocks), 1093 from_dblock(new_nr_entries), 1094 false, &cmd->discard_root); 1095 if (!r) { 1096 cmd->discard_block_size = discard_block_size; 1097 cmd->discard_nr_blocks = new_nr_entries; 1098 } 1099 1100 cmd->changed = true; 1101 WRITE_UNLOCK(cmd); 1102 1103 return r; 1104 } 1105 1106 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1107 { 1108 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, 1109 from_dblock(b), &cmd->discard_root); 1110 } 1111 1112 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) 1113 { 1114 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, 1115 from_dblock(b), &cmd->discard_root); 1116 } 1117 1118 static int __discard(struct dm_cache_metadata *cmd, 1119 dm_dblock_t dblock, bool discard) 1120 { 1121 int r; 1122 1123 r = (discard ? __set_discard : __clear_discard)(cmd, dblock); 1124 if (r) 1125 return r; 1126 1127 cmd->changed = true; 1128 return 0; 1129 } 1130 1131 int dm_cache_set_discard(struct dm_cache_metadata *cmd, 1132 dm_dblock_t dblock, bool discard) 1133 { 1134 int r; 1135 1136 WRITE_LOCK(cmd); 1137 r = __discard(cmd, dblock, discard); 1138 WRITE_UNLOCK(cmd); 1139 1140 return r; 1141 } 1142 1143 static int __load_discards(struct dm_cache_metadata *cmd, 1144 load_discard_fn fn, void *context) 1145 { 1146 int r = 0; 1147 uint32_t b; 1148 struct dm_bitset_cursor c; 1149 1150 if (from_dblock(cmd->discard_nr_blocks) == 0) 1151 /* nothing to do */ 1152 return 0; 1153 1154 if (cmd->clean_when_opened) { 1155 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root); 1156 if (r) 1157 return r; 1158 1159 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root, 1160 from_dblock(cmd->discard_nr_blocks), &c); 1161 if (r) 1162 return r; 1163 1164 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1165 r = fn(context, cmd->discard_block_size, to_dblock(b), 1166 dm_bitset_cursor_get_value(&c)); 1167 if (r) 1168 break; 1169 } 1170 1171 dm_bitset_cursor_end(&c); 1172 1173 } else { 1174 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { 1175 r = fn(context, cmd->discard_block_size, to_dblock(b), false); 1176 if (r) 1177 return r; 1178 } 1179 } 1180 1181 return r; 1182 } 1183 1184 int dm_cache_load_discards(struct dm_cache_metadata *cmd, 1185 load_discard_fn fn, void *context) 1186 { 1187 int r; 1188 1189 READ_LOCK(cmd); 1190 r = __load_discards(cmd, fn, context); 1191 READ_UNLOCK(cmd); 1192 1193 return r; 1194 } 1195 1196 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result) 1197 { 1198 READ_LOCK(cmd); 1199 *result = cmd->cache_blocks; 1200 READ_UNLOCK(cmd); 1201 1202 return 0; 1203 } 1204 1205 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1206 { 1207 int r; 1208 __le64 value = pack_value(0, 0); 1209 1210 __dm_bless_for_disk(&value); 1211 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1212 &value, &cmd->root); 1213 if (r) 1214 return r; 1215 1216 cmd->changed = true; 1217 return 0; 1218 } 1219 1220 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) 1221 { 1222 int r; 1223 1224 WRITE_LOCK(cmd); 1225 r = __remove(cmd, cblock); 1226 WRITE_UNLOCK(cmd); 1227 1228 return r; 1229 } 1230 1231 static int __insert(struct dm_cache_metadata *cmd, 1232 dm_cblock_t cblock, dm_oblock_t oblock) 1233 { 1234 int r; 1235 __le64 value = pack_value(oblock, M_VALID); 1236 __dm_bless_for_disk(&value); 1237 1238 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1239 &value, &cmd->root); 1240 if (r) 1241 return r; 1242 1243 cmd->changed = true; 1244 return 0; 1245 } 1246 1247 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, 1248 dm_cblock_t cblock, dm_oblock_t oblock) 1249 { 1250 int r; 1251 1252 WRITE_LOCK(cmd); 1253 r = __insert(cmd, cblock, oblock); 1254 WRITE_UNLOCK(cmd); 1255 1256 return r; 1257 } 1258 1259 struct thunk { 1260 load_mapping_fn fn; 1261 void *context; 1262 1263 struct dm_cache_metadata *cmd; 1264 bool respect_dirty_flags; 1265 bool hints_valid; 1266 }; 1267 1268 static bool policy_unchanged(struct dm_cache_metadata *cmd, 1269 struct dm_cache_policy *policy) 1270 { 1271 const char *policy_name = dm_cache_policy_get_name(policy); 1272 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1273 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); 1274 1275 /* 1276 * Ensure policy names match. 1277 */ 1278 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) 1279 return false; 1280 1281 /* 1282 * Ensure policy major versions match. 1283 */ 1284 if (cmd->policy_version[0] != policy_version[0]) 1285 return false; 1286 1287 /* 1288 * Ensure policy hint sizes match. 1289 */ 1290 if (cmd->policy_hint_size != policy_hint_size) 1291 return false; 1292 1293 return true; 1294 } 1295 1296 static bool hints_array_initialized(struct dm_cache_metadata *cmd) 1297 { 1298 return cmd->hint_root && cmd->policy_hint_size; 1299 } 1300 1301 static bool hints_array_available(struct dm_cache_metadata *cmd, 1302 struct dm_cache_policy *policy) 1303 { 1304 return cmd->clean_when_opened && policy_unchanged(cmd, policy) && 1305 hints_array_initialized(cmd); 1306 } 1307 1308 static int __load_mapping_v1(struct dm_cache_metadata *cmd, 1309 uint64_t cb, bool hints_valid, 1310 struct dm_array_cursor *mapping_cursor, 1311 struct dm_array_cursor *hint_cursor, 1312 load_mapping_fn fn, void *context) 1313 { 1314 int r = 0; 1315 1316 __le64 mapping; 1317 __le32 hint = 0; 1318 1319 __le64 *mapping_value_le; 1320 __le32 *hint_value_le; 1321 1322 dm_oblock_t oblock; 1323 unsigned flags; 1324 1325 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1326 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1327 unpack_value(mapping, &oblock, &flags); 1328 1329 if (flags & M_VALID) { 1330 if (hints_valid) { 1331 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1332 memcpy(&hint, hint_value_le, sizeof(hint)); 1333 } 1334 1335 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY, 1336 le32_to_cpu(hint), hints_valid); 1337 if (r) { 1338 DMERR("policy couldn't load cache block %llu", 1339 (unsigned long long) from_cblock(to_cblock(cb))); 1340 } 1341 } 1342 1343 return r; 1344 } 1345 1346 static int __load_mapping_v2(struct dm_cache_metadata *cmd, 1347 uint64_t cb, bool hints_valid, 1348 struct dm_array_cursor *mapping_cursor, 1349 struct dm_array_cursor *hint_cursor, 1350 struct dm_bitset_cursor *dirty_cursor, 1351 load_mapping_fn fn, void *context) 1352 { 1353 int r = 0; 1354 1355 __le64 mapping; 1356 __le32 hint = 0; 1357 1358 __le64 *mapping_value_le; 1359 __le32 *hint_value_le; 1360 1361 dm_oblock_t oblock; 1362 unsigned flags; 1363 bool dirty; 1364 1365 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); 1366 memcpy(&mapping, mapping_value_le, sizeof(mapping)); 1367 unpack_value(mapping, &oblock, &flags); 1368 1369 if (flags & M_VALID) { 1370 if (hints_valid) { 1371 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); 1372 memcpy(&hint, hint_value_le, sizeof(hint)); 1373 } 1374 1375 dirty = dm_bitset_cursor_get_value(dirty_cursor); 1376 r = fn(context, oblock, to_cblock(cb), dirty, 1377 le32_to_cpu(hint), hints_valid); 1378 if (r) { 1379 DMERR("policy couldn't load cache block %llu", 1380 (unsigned long long) from_cblock(to_cblock(cb))); 1381 } 1382 } 1383 1384 return r; 1385 } 1386 1387 static int __load_mappings(struct dm_cache_metadata *cmd, 1388 struct dm_cache_policy *policy, 1389 load_mapping_fn fn, void *context) 1390 { 1391 int r; 1392 uint64_t cb; 1393 1394 bool hints_valid = hints_array_available(cmd, policy); 1395 1396 if (from_cblock(cmd->cache_blocks) == 0) 1397 /* Nothing to do */ 1398 return 0; 1399 1400 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor); 1401 if (r) 1402 return r; 1403 1404 if (hints_valid) { 1405 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor); 1406 if (r) { 1407 dm_array_cursor_end(&cmd->mapping_cursor); 1408 return r; 1409 } 1410 } 1411 1412 if (separate_dirty_bits(cmd)) { 1413 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, 1414 from_cblock(cmd->cache_blocks), 1415 &cmd->dirty_cursor); 1416 if (r) { 1417 dm_array_cursor_end(&cmd->hint_cursor); 1418 dm_array_cursor_end(&cmd->mapping_cursor); 1419 return r; 1420 } 1421 } 1422 1423 for (cb = 0; ; cb++) { 1424 if (separate_dirty_bits(cmd)) 1425 r = __load_mapping_v2(cmd, cb, hints_valid, 1426 &cmd->mapping_cursor, 1427 &cmd->hint_cursor, 1428 &cmd->dirty_cursor, 1429 fn, context); 1430 else 1431 r = __load_mapping_v1(cmd, cb, hints_valid, 1432 &cmd->mapping_cursor, &cmd->hint_cursor, 1433 fn, context); 1434 if (r) 1435 goto out; 1436 1437 /* 1438 * We need to break out before we move the cursors. 1439 */ 1440 if (cb >= (from_cblock(cmd->cache_blocks) - 1)) 1441 break; 1442 1443 r = dm_array_cursor_next(&cmd->mapping_cursor); 1444 if (r) { 1445 DMERR("dm_array_cursor_next for mapping failed"); 1446 goto out; 1447 } 1448 1449 if (hints_valid) { 1450 r = dm_array_cursor_next(&cmd->hint_cursor); 1451 if (r) { 1452 DMERR("dm_array_cursor_next for hint failed"); 1453 goto out; 1454 } 1455 } 1456 1457 if (separate_dirty_bits(cmd)) { 1458 r = dm_bitset_cursor_next(&cmd->dirty_cursor); 1459 if (r) { 1460 DMERR("dm_bitset_cursor_next for dirty failed"); 1461 goto out; 1462 } 1463 } 1464 } 1465 out: 1466 dm_array_cursor_end(&cmd->mapping_cursor); 1467 if (hints_valid) 1468 dm_array_cursor_end(&cmd->hint_cursor); 1469 1470 if (separate_dirty_bits(cmd)) 1471 dm_bitset_cursor_end(&cmd->dirty_cursor); 1472 1473 return r; 1474 } 1475 1476 int dm_cache_load_mappings(struct dm_cache_metadata *cmd, 1477 struct dm_cache_policy *policy, 1478 load_mapping_fn fn, void *context) 1479 { 1480 int r; 1481 1482 READ_LOCK(cmd); 1483 r = __load_mappings(cmd, policy, fn, context); 1484 READ_UNLOCK(cmd); 1485 1486 return r; 1487 } 1488 1489 static int __dump_mapping(void *context, uint64_t cblock, void *leaf) 1490 { 1491 int r = 0; 1492 __le64 value; 1493 dm_oblock_t oblock; 1494 unsigned flags; 1495 1496 memcpy(&value, leaf, sizeof(value)); 1497 unpack_value(value, &oblock, &flags); 1498 1499 return r; 1500 } 1501 1502 static int __dump_mappings(struct dm_cache_metadata *cmd) 1503 { 1504 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); 1505 } 1506 1507 void dm_cache_dump(struct dm_cache_metadata *cmd) 1508 { 1509 READ_LOCK_VOID(cmd); 1510 __dump_mappings(cmd); 1511 READ_UNLOCK(cmd); 1512 } 1513 1514 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) 1515 { 1516 int r; 1517 1518 READ_LOCK(cmd); 1519 r = cmd->changed; 1520 READ_UNLOCK(cmd); 1521 1522 return r; 1523 } 1524 1525 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) 1526 { 1527 int r; 1528 unsigned flags; 1529 dm_oblock_t oblock; 1530 __le64 value; 1531 1532 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); 1533 if (r) 1534 return r; 1535 1536 unpack_value(value, &oblock, &flags); 1537 1538 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) 1539 /* nothing to be done */ 1540 return 0; 1541 1542 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); 1543 __dm_bless_for_disk(&value); 1544 1545 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), 1546 &value, &cmd->root); 1547 if (r) 1548 return r; 1549 1550 cmd->changed = true; 1551 return 0; 1552 1553 } 1554 1555 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1556 { 1557 int r; 1558 unsigned i; 1559 for (i = 0; i < nr_bits; i++) { 1560 r = __dirty(cmd, to_cblock(i), test_bit(i, bits)); 1561 if (r) 1562 return r; 1563 } 1564 1565 return 0; 1566 } 1567 1568 static int is_dirty_callback(uint32_t index, bool *value, void *context) 1569 { 1570 unsigned long *bits = context; 1571 *value = test_bit(index, bits); 1572 return 0; 1573 } 1574 1575 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits) 1576 { 1577 int r = 0; 1578 1579 /* nr_bits is really just a sanity check */ 1580 if (nr_bits != from_cblock(cmd->cache_blocks)) { 1581 DMERR("dirty bitset is wrong size"); 1582 return -EINVAL; 1583 } 1584 1585 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root); 1586 if (r) 1587 return r; 1588 1589 cmd->changed = true; 1590 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits); 1591 } 1592 1593 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, 1594 unsigned nr_bits, 1595 unsigned long *bits) 1596 { 1597 int r; 1598 1599 WRITE_LOCK(cmd); 1600 if (separate_dirty_bits(cmd)) 1601 r = __set_dirty_bits_v2(cmd, nr_bits, bits); 1602 else 1603 r = __set_dirty_bits_v1(cmd, nr_bits, bits); 1604 WRITE_UNLOCK(cmd); 1605 1606 return r; 1607 } 1608 1609 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, 1610 struct dm_cache_statistics *stats) 1611 { 1612 READ_LOCK_VOID(cmd); 1613 *stats = cmd->stats; 1614 READ_UNLOCK(cmd); 1615 } 1616 1617 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, 1618 struct dm_cache_statistics *stats) 1619 { 1620 WRITE_LOCK_VOID(cmd); 1621 cmd->stats = *stats; 1622 WRITE_UNLOCK(cmd); 1623 } 1624 1625 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) 1626 { 1627 int r = -EINVAL; 1628 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : 1629 clear_clean_shutdown); 1630 1631 WRITE_LOCK(cmd); 1632 if (cmd->fail_io) 1633 goto out; 1634 1635 r = __commit_transaction(cmd, mutator); 1636 if (r) 1637 goto out; 1638 1639 r = __begin_transaction(cmd); 1640 out: 1641 WRITE_UNLOCK(cmd); 1642 return r; 1643 } 1644 1645 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, 1646 dm_block_t *result) 1647 { 1648 int r = -EINVAL; 1649 1650 READ_LOCK(cmd); 1651 if (!cmd->fail_io) 1652 r = dm_sm_get_nr_free(cmd->metadata_sm, result); 1653 READ_UNLOCK(cmd); 1654 1655 return r; 1656 } 1657 1658 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, 1659 dm_block_t *result) 1660 { 1661 int r = -EINVAL; 1662 1663 READ_LOCK(cmd); 1664 if (!cmd->fail_io) 1665 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); 1666 READ_UNLOCK(cmd); 1667 1668 return r; 1669 } 1670 1671 /*----------------------------------------------------------------*/ 1672 1673 static int get_hint(uint32_t index, void *value_le, void *context) 1674 { 1675 uint32_t value; 1676 struct dm_cache_policy *policy = context; 1677 1678 value = policy_get_hint(policy, to_cblock(index)); 1679 *((__le32 *) value_le) = cpu_to_le32(value); 1680 1681 return 0; 1682 } 1683 1684 /* 1685 * It's quicker to always delete the hint array, and recreate with 1686 * dm_array_new(). 1687 */ 1688 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1689 { 1690 int r; 1691 size_t hint_size; 1692 const char *policy_name = dm_cache_policy_get_name(policy); 1693 const unsigned *policy_version = dm_cache_policy_get_version(policy); 1694 1695 if (!policy_name[0] || 1696 (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) 1697 return -EINVAL; 1698 1699 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); 1700 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); 1701 1702 hint_size = dm_cache_policy_get_hint_size(policy); 1703 if (!hint_size) 1704 return 0; /* short-circuit hints initialization */ 1705 cmd->policy_hint_size = hint_size; 1706 1707 if (cmd->hint_root) { 1708 r = dm_array_del(&cmd->hint_info, cmd->hint_root); 1709 if (r) 1710 return r; 1711 } 1712 1713 return dm_array_new(&cmd->hint_info, &cmd->hint_root, 1714 from_cblock(cmd->cache_blocks), 1715 get_hint, policy); 1716 } 1717 1718 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) 1719 { 1720 int r; 1721 1722 WRITE_LOCK(cmd); 1723 r = write_hints(cmd, policy); 1724 WRITE_UNLOCK(cmd); 1725 1726 return r; 1727 } 1728 1729 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) 1730 { 1731 int r; 1732 1733 READ_LOCK(cmd); 1734 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); 1735 READ_UNLOCK(cmd); 1736 1737 return r; 1738 } 1739 1740 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) 1741 { 1742 WRITE_LOCK_VOID(cmd); 1743 dm_bm_set_read_only(cmd->bm); 1744 WRITE_UNLOCK(cmd); 1745 } 1746 1747 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) 1748 { 1749 WRITE_LOCK_VOID(cmd); 1750 dm_bm_set_read_write(cmd->bm); 1751 WRITE_UNLOCK(cmd); 1752 } 1753 1754 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) 1755 { 1756 int r; 1757 struct dm_block *sblock; 1758 struct cache_disk_superblock *disk_super; 1759 1760 WRITE_LOCK(cmd); 1761 set_bit(NEEDS_CHECK, &cmd->flags); 1762 1763 r = superblock_lock(cmd, &sblock); 1764 if (r) { 1765 DMERR("couldn't read superblock"); 1766 goto out; 1767 } 1768 1769 disk_super = dm_block_data(sblock); 1770 disk_super->flags = cpu_to_le32(cmd->flags); 1771 1772 dm_bm_unlock(sblock); 1773 1774 out: 1775 WRITE_UNLOCK(cmd); 1776 return r; 1777 } 1778 1779 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) 1780 { 1781 READ_LOCK(cmd); 1782 *result = !!test_bit(NEEDS_CHECK, &cmd->flags); 1783 READ_UNLOCK(cmd); 1784 1785 return 0; 1786 } 1787 1788 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) 1789 { 1790 int r; 1791 1792 WRITE_LOCK(cmd); 1793 __destroy_persistent_data_objects(cmd); 1794 r = __create_persistent_data_objects(cmd, false); 1795 if (r) 1796 cmd->fail_io = true; 1797 WRITE_UNLOCK(cmd); 1798 1799 return r; 1800 } 1801