1 // SPDX-License-Identifier: GPL-2.0-only 2 #include "dm.h" 3 #include "persistent-data/dm-transaction-manager.h" 4 #include "persistent-data/dm-bitset.h" 5 #include "persistent-data/dm-space-map.h" 6 7 #include <linux/dm-io.h> 8 #include <linux/dm-kcopyd.h> 9 #include <linux/init.h> 10 #include <linux/mempool.h> 11 #include <linux/module.h> 12 #include <linux/slab.h> 13 #include <linux/vmalloc.h> 14 15 #define DM_MSG_PREFIX "era" 16 17 #define SUPERBLOCK_LOCATION 0 18 #define SUPERBLOCK_MAGIC 2126579579 19 #define SUPERBLOCK_CSUM_XOR 146538381 20 #define MIN_ERA_VERSION 1 21 #define MAX_ERA_VERSION 1 22 #define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION 23 #define MIN_BLOCK_SIZE 8 24 25 /*---------------------------------------------------------------- 26 * Writeset 27 *--------------------------------------------------------------*/ 28 struct writeset_metadata { 29 uint32_t nr_bits; 30 dm_block_t root; 31 }; 32 33 struct writeset { 34 struct writeset_metadata md; 35 36 /* 37 * An in core copy of the bits to save constantly doing look ups on 38 * disk. 39 */ 40 unsigned long *bits; 41 }; 42 43 /* 44 * This does not free off the on disk bitset as this will normally be done 45 * after digesting into the era array. 46 */ 47 static void writeset_free(struct writeset *ws) 48 { 49 vfree(ws->bits); 50 ws->bits = NULL; 51 } 52 53 static int setup_on_disk_bitset(struct dm_disk_bitset *info, 54 unsigned nr_bits, dm_block_t *root) 55 { 56 int r; 57 58 r = dm_bitset_empty(info, root); 59 if (r) 60 return r; 61 62 return dm_bitset_resize(info, *root, 0, nr_bits, false, root); 63 } 64 65 static size_t bitset_size(unsigned nr_bits) 66 { 67 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG); 68 } 69 70 /* 71 * Allocates memory for the in core bitset. 72 */ 73 static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks) 74 { 75 ws->bits = vzalloc(bitset_size(nr_blocks)); 76 if (!ws->bits) { 77 DMERR("%s: couldn't allocate in memory bitset", __func__); 78 return -ENOMEM; 79 } 80 81 return 0; 82 } 83 84 /* 85 * Wipes the in-core bitset, and creates a new on disk bitset. 86 */ 87 static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws, 88 dm_block_t nr_blocks) 89 { 90 int r; 91 92 memset(ws->bits, 0, bitset_size(nr_blocks)); 93 94 ws->md.nr_bits = nr_blocks; 95 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root); 96 if (r) { 97 DMERR("%s: setup_on_disk_bitset failed", __func__); 98 return r; 99 } 100 101 return 0; 102 } 103 104 static bool writeset_marked(struct writeset *ws, dm_block_t block) 105 { 106 return test_bit(block, ws->bits); 107 } 108 109 static int writeset_marked_on_disk(struct dm_disk_bitset *info, 110 struct writeset_metadata *m, dm_block_t block, 111 bool *result) 112 { 113 dm_block_t old = m->root; 114 115 /* 116 * The bitset was flushed when it was archived, so we know there'll 117 * be no change to the root. 118 */ 119 int r = dm_bitset_test_bit(info, m->root, block, &m->root, result); 120 if (r) { 121 DMERR("%s: dm_bitset_test_bit failed", __func__); 122 return r; 123 } 124 125 BUG_ON(m->root != old); 126 127 return r; 128 } 129 130 /* 131 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was. 132 */ 133 static int writeset_test_and_set(struct dm_disk_bitset *info, 134 struct writeset *ws, uint32_t block) 135 { 136 int r; 137 138 if (!test_bit(block, ws->bits)) { 139 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root); 140 if (r) { 141 /* FIXME: fail mode */ 142 return r; 143 } 144 145 return 0; 146 } 147 148 return 1; 149 } 150 151 /*---------------------------------------------------------------- 152 * On disk metadata layout 153 *--------------------------------------------------------------*/ 154 #define SPACE_MAP_ROOT_SIZE 128 155 #define UUID_LEN 16 156 157 struct writeset_disk { 158 __le32 nr_bits; 159 __le64 root; 160 } __packed; 161 162 struct superblock_disk { 163 __le32 csum; 164 __le32 flags; 165 __le64 blocknr; 166 167 __u8 uuid[UUID_LEN]; 168 __le64 magic; 169 __le32 version; 170 171 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 172 173 __le32 data_block_size; 174 __le32 metadata_block_size; 175 __le32 nr_blocks; 176 177 __le32 current_era; 178 struct writeset_disk current_writeset; 179 180 /* 181 * Only these two fields are valid within the metadata snapshot. 182 */ 183 __le64 writeset_tree_root; 184 __le64 era_array_root; 185 186 __le64 metadata_snap; 187 } __packed; 188 189 /*---------------------------------------------------------------- 190 * Superblock validation 191 *--------------------------------------------------------------*/ 192 static void sb_prepare_for_write(struct dm_block_validator *v, 193 struct dm_block *b, 194 size_t sb_block_size) 195 { 196 struct superblock_disk *disk = dm_block_data(b); 197 198 disk->blocknr = cpu_to_le64(dm_block_location(b)); 199 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags, 200 sb_block_size - sizeof(__le32), 201 SUPERBLOCK_CSUM_XOR)); 202 } 203 204 static int check_metadata_version(struct superblock_disk *disk) 205 { 206 uint32_t metadata_version = le32_to_cpu(disk->version); 207 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) { 208 DMERR("Era metadata version %u found, but only versions between %u and %u supported.", 209 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION); 210 return -EINVAL; 211 } 212 213 return 0; 214 } 215 216 static int sb_check(struct dm_block_validator *v, 217 struct dm_block *b, 218 size_t sb_block_size) 219 { 220 struct superblock_disk *disk = dm_block_data(b); 221 __le32 csum_le; 222 223 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) { 224 DMERR("sb_check failed: blocknr %llu: wanted %llu", 225 le64_to_cpu(disk->blocknr), 226 (unsigned long long)dm_block_location(b)); 227 return -ENOTBLK; 228 } 229 230 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) { 231 DMERR("sb_check failed: magic %llu: wanted %llu", 232 le64_to_cpu(disk->magic), 233 (unsigned long long) SUPERBLOCK_MAGIC); 234 return -EILSEQ; 235 } 236 237 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags, 238 sb_block_size - sizeof(__le32), 239 SUPERBLOCK_CSUM_XOR)); 240 if (csum_le != disk->csum) { 241 DMERR("sb_check failed: csum %u: wanted %u", 242 le32_to_cpu(csum_le), le32_to_cpu(disk->csum)); 243 return -EILSEQ; 244 } 245 246 return check_metadata_version(disk); 247 } 248 249 static struct dm_block_validator sb_validator = { 250 .name = "superblock", 251 .prepare_for_write = sb_prepare_for_write, 252 .check = sb_check 253 }; 254 255 /*---------------------------------------------------------------- 256 * Low level metadata handling 257 *--------------------------------------------------------------*/ 258 #define DM_ERA_METADATA_BLOCK_SIZE 4096 259 #define ERA_MAX_CONCURRENT_LOCKS 5 260 261 struct era_metadata { 262 struct block_device *bdev; 263 struct dm_block_manager *bm; 264 struct dm_space_map *sm; 265 struct dm_transaction_manager *tm; 266 267 dm_block_t block_size; 268 uint32_t nr_blocks; 269 270 uint32_t current_era; 271 272 /* 273 * We preallocate 2 writesets. When an era rolls over we 274 * switch between them. This means the allocation is done at 275 * preresume time, rather than on the io path. 276 */ 277 struct writeset writesets[2]; 278 struct writeset *current_writeset; 279 280 dm_block_t writeset_tree_root; 281 dm_block_t era_array_root; 282 283 struct dm_disk_bitset bitset_info; 284 struct dm_btree_info writeset_tree_info; 285 struct dm_array_info era_array_info; 286 287 dm_block_t metadata_snap; 288 289 /* 290 * A flag that is set whenever a writeset has been archived. 291 */ 292 bool archived_writesets; 293 294 /* 295 * Reading the space map root can fail, so we read it into this 296 * buffer before the superblock is locked and updated. 297 */ 298 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; 299 }; 300 301 static int superblock_read_lock(struct era_metadata *md, 302 struct dm_block **sblock) 303 { 304 return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION, 305 &sb_validator, sblock); 306 } 307 308 static int superblock_lock_zero(struct era_metadata *md, 309 struct dm_block **sblock) 310 { 311 return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION, 312 &sb_validator, sblock); 313 } 314 315 static int superblock_lock(struct era_metadata *md, 316 struct dm_block **sblock) 317 { 318 return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION, 319 &sb_validator, sblock); 320 } 321 322 /* FIXME: duplication with cache and thin */ 323 static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result) 324 { 325 int r; 326 unsigned i; 327 struct dm_block *b; 328 __le64 *data_le, zero = cpu_to_le64(0); 329 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); 330 331 /* 332 * We can't use a validator here - it may be all zeroes. 333 */ 334 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b); 335 if (r) 336 return r; 337 338 data_le = dm_block_data(b); 339 *result = true; 340 for (i = 0; i < sb_block_size; i++) { 341 if (data_le[i] != zero) { 342 *result = false; 343 break; 344 } 345 } 346 347 dm_bm_unlock(b); 348 349 return 0; 350 } 351 352 /*----------------------------------------------------------------*/ 353 354 static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk) 355 { 356 disk->nr_bits = cpu_to_le32(core->nr_bits); 357 disk->root = cpu_to_le64(core->root); 358 } 359 360 static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core) 361 { 362 core->nr_bits = le32_to_cpu(disk->nr_bits); 363 core->root = le64_to_cpu(disk->root); 364 } 365 366 static void ws_inc(void *context, const void *value, unsigned count) 367 { 368 struct era_metadata *md = context; 369 struct writeset_disk ws_d; 370 dm_block_t b; 371 unsigned i; 372 373 for (i = 0; i < count; i++) { 374 memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d)); 375 b = le64_to_cpu(ws_d.root); 376 dm_tm_inc(md->tm, b); 377 } 378 } 379 380 static void ws_dec(void *context, const void *value, unsigned count) 381 { 382 struct era_metadata *md = context; 383 struct writeset_disk ws_d; 384 dm_block_t b; 385 unsigned i; 386 387 for (i = 0; i < count; i++) { 388 memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d)); 389 b = le64_to_cpu(ws_d.root); 390 dm_bitset_del(&md->bitset_info, b); 391 } 392 } 393 394 static int ws_eq(void *context, const void *value1, const void *value2) 395 { 396 return !memcmp(value1, value2, sizeof(struct writeset_disk)); 397 } 398 399 /*----------------------------------------------------------------*/ 400 401 static void setup_writeset_tree_info(struct era_metadata *md) 402 { 403 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type; 404 md->writeset_tree_info.tm = md->tm; 405 md->writeset_tree_info.levels = 1; 406 vt->context = md; 407 vt->size = sizeof(struct writeset_disk); 408 vt->inc = ws_inc; 409 vt->dec = ws_dec; 410 vt->equal = ws_eq; 411 } 412 413 static void setup_era_array_info(struct era_metadata *md) 414 415 { 416 struct dm_btree_value_type vt; 417 vt.context = NULL; 418 vt.size = sizeof(__le32); 419 vt.inc = NULL; 420 vt.dec = NULL; 421 vt.equal = NULL; 422 423 dm_array_info_init(&md->era_array_info, md->tm, &vt); 424 } 425 426 static void setup_infos(struct era_metadata *md) 427 { 428 dm_disk_bitset_init(md->tm, &md->bitset_info); 429 setup_writeset_tree_info(md); 430 setup_era_array_info(md); 431 } 432 433 /*----------------------------------------------------------------*/ 434 435 static int create_fresh_metadata(struct era_metadata *md) 436 { 437 int r; 438 439 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION, 440 &md->tm, &md->sm); 441 if (r < 0) { 442 DMERR("dm_tm_create_with_sm failed"); 443 return r; 444 } 445 446 setup_infos(md); 447 448 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root); 449 if (r) { 450 DMERR("couldn't create new writeset tree"); 451 goto bad; 452 } 453 454 r = dm_array_empty(&md->era_array_info, &md->era_array_root); 455 if (r) { 456 DMERR("couldn't create era array"); 457 goto bad; 458 } 459 460 return 0; 461 462 bad: 463 dm_sm_destroy(md->sm); 464 dm_tm_destroy(md->tm); 465 466 return r; 467 } 468 469 static int save_sm_root(struct era_metadata *md) 470 { 471 int r; 472 size_t metadata_len; 473 474 r = dm_sm_root_size(md->sm, &metadata_len); 475 if (r < 0) 476 return r; 477 478 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root, 479 metadata_len); 480 } 481 482 static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk) 483 { 484 memcpy(&disk->metadata_space_map_root, 485 &md->metadata_space_map_root, 486 sizeof(md->metadata_space_map_root)); 487 } 488 489 /* 490 * Writes a superblock, including the static fields that don't get updated 491 * with every commit (possible optimisation here). 'md' should be fully 492 * constructed when this is called. 493 */ 494 static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk) 495 { 496 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC); 497 disk->flags = cpu_to_le32(0ul); 498 499 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */ 500 memset(disk->uuid, 0, sizeof(disk->uuid)); 501 disk->version = cpu_to_le32(MAX_ERA_VERSION); 502 503 copy_sm_root(md, disk); 504 505 disk->data_block_size = cpu_to_le32(md->block_size); 506 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); 507 disk->nr_blocks = cpu_to_le32(md->nr_blocks); 508 disk->current_era = cpu_to_le32(md->current_era); 509 510 ws_pack(&md->current_writeset->md, &disk->current_writeset); 511 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root); 512 disk->era_array_root = cpu_to_le64(md->era_array_root); 513 disk->metadata_snap = cpu_to_le64(md->metadata_snap); 514 } 515 516 static int write_superblock(struct era_metadata *md) 517 { 518 int r; 519 struct dm_block *sblock; 520 struct superblock_disk *disk; 521 522 r = save_sm_root(md); 523 if (r) { 524 DMERR("%s: save_sm_root failed", __func__); 525 return r; 526 } 527 528 r = superblock_lock_zero(md, &sblock); 529 if (r) 530 return r; 531 532 disk = dm_block_data(sblock); 533 prepare_superblock(md, disk); 534 535 return dm_tm_commit(md->tm, sblock); 536 } 537 538 /* 539 * Assumes block_size and the infos are set. 540 */ 541 static int format_metadata(struct era_metadata *md) 542 { 543 int r; 544 545 r = create_fresh_metadata(md); 546 if (r) 547 return r; 548 549 r = write_superblock(md); 550 if (r) { 551 dm_sm_destroy(md->sm); 552 dm_tm_destroy(md->tm); 553 return r; 554 } 555 556 return 0; 557 } 558 559 static int open_metadata(struct era_metadata *md) 560 { 561 int r; 562 struct dm_block *sblock; 563 struct superblock_disk *disk; 564 565 r = superblock_read_lock(md, &sblock); 566 if (r) { 567 DMERR("couldn't read_lock superblock"); 568 return r; 569 } 570 571 disk = dm_block_data(sblock); 572 573 /* Verify the data block size hasn't changed */ 574 if (le32_to_cpu(disk->data_block_size) != md->block_size) { 575 DMERR("changing the data block size (from %u to %llu) is not supported", 576 le32_to_cpu(disk->data_block_size), md->block_size); 577 r = -EINVAL; 578 goto bad; 579 } 580 581 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION, 582 disk->metadata_space_map_root, 583 sizeof(disk->metadata_space_map_root), 584 &md->tm, &md->sm); 585 if (r) { 586 DMERR("dm_tm_open_with_sm failed"); 587 goto bad; 588 } 589 590 setup_infos(md); 591 592 md->nr_blocks = le32_to_cpu(disk->nr_blocks); 593 md->current_era = le32_to_cpu(disk->current_era); 594 595 ws_unpack(&disk->current_writeset, &md->current_writeset->md); 596 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root); 597 md->era_array_root = le64_to_cpu(disk->era_array_root); 598 md->metadata_snap = le64_to_cpu(disk->metadata_snap); 599 md->archived_writesets = true; 600 601 dm_bm_unlock(sblock); 602 603 return 0; 604 605 bad: 606 dm_bm_unlock(sblock); 607 return r; 608 } 609 610 static int open_or_format_metadata(struct era_metadata *md, 611 bool may_format) 612 { 613 int r; 614 bool unformatted = false; 615 616 r = superblock_all_zeroes(md->bm, &unformatted); 617 if (r) 618 return r; 619 620 if (unformatted) 621 return may_format ? format_metadata(md) : -EPERM; 622 623 return open_metadata(md); 624 } 625 626 static int create_persistent_data_objects(struct era_metadata *md, 627 bool may_format) 628 { 629 int r; 630 631 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE, 632 ERA_MAX_CONCURRENT_LOCKS); 633 if (IS_ERR(md->bm)) { 634 DMERR("could not create block manager"); 635 return PTR_ERR(md->bm); 636 } 637 638 r = open_or_format_metadata(md, may_format); 639 if (r) 640 dm_block_manager_destroy(md->bm); 641 642 return r; 643 } 644 645 static void destroy_persistent_data_objects(struct era_metadata *md) 646 { 647 dm_sm_destroy(md->sm); 648 dm_tm_destroy(md->tm); 649 dm_block_manager_destroy(md->bm); 650 } 651 652 /* 653 * This waits until all era_map threads have picked up the new filter. 654 */ 655 static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset) 656 { 657 rcu_assign_pointer(md->current_writeset, new_writeset); 658 synchronize_rcu(); 659 } 660 661 /*---------------------------------------------------------------- 662 * Writesets get 'digested' into the main era array. 663 * 664 * We're using a coroutine here so the worker thread can do the digestion, 665 * thus avoiding synchronisation of the metadata. Digesting a whole 666 * writeset in one go would cause too much latency. 667 *--------------------------------------------------------------*/ 668 struct digest { 669 uint32_t era; 670 unsigned nr_bits, current_bit; 671 struct writeset_metadata writeset; 672 __le32 value; 673 struct dm_disk_bitset info; 674 675 int (*step)(struct era_metadata *, struct digest *); 676 }; 677 678 static int metadata_digest_lookup_writeset(struct era_metadata *md, 679 struct digest *d); 680 681 static int metadata_digest_remove_writeset(struct era_metadata *md, 682 struct digest *d) 683 { 684 int r; 685 uint64_t key = d->era; 686 687 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root, 688 &key, &md->writeset_tree_root); 689 if (r) { 690 DMERR("%s: dm_btree_remove failed", __func__); 691 return r; 692 } 693 694 d->step = metadata_digest_lookup_writeset; 695 return 0; 696 } 697 698 #define INSERTS_PER_STEP 100 699 700 static int metadata_digest_transcribe_writeset(struct era_metadata *md, 701 struct digest *d) 702 { 703 int r; 704 bool marked; 705 unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits); 706 707 for (b = d->current_bit; b < e; b++) { 708 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked); 709 if (r) { 710 DMERR("%s: writeset_marked_on_disk failed", __func__); 711 return r; 712 } 713 714 if (!marked) 715 continue; 716 717 __dm_bless_for_disk(&d->value); 718 r = dm_array_set_value(&md->era_array_info, md->era_array_root, 719 b, &d->value, &md->era_array_root); 720 if (r) { 721 DMERR("%s: dm_array_set_value failed", __func__); 722 return r; 723 } 724 } 725 726 if (b == d->nr_bits) 727 d->step = metadata_digest_remove_writeset; 728 else 729 d->current_bit = b; 730 731 return 0; 732 } 733 734 static int metadata_digest_lookup_writeset(struct era_metadata *md, 735 struct digest *d) 736 { 737 int r; 738 uint64_t key; 739 struct writeset_disk disk; 740 741 r = dm_btree_find_lowest_key(&md->writeset_tree_info, 742 md->writeset_tree_root, &key); 743 if (r < 0) 744 return r; 745 746 d->era = key; 747 748 r = dm_btree_lookup(&md->writeset_tree_info, 749 md->writeset_tree_root, &key, &disk); 750 if (r) { 751 if (r == -ENODATA) { 752 d->step = NULL; 753 return 0; 754 } 755 756 DMERR("%s: dm_btree_lookup failed", __func__); 757 return r; 758 } 759 760 ws_unpack(&disk, &d->writeset); 761 d->value = cpu_to_le32(key); 762 763 /* 764 * We initialise another bitset info to avoid any caching side effects 765 * with the previous one. 766 */ 767 dm_disk_bitset_init(md->tm, &d->info); 768 769 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks); 770 d->current_bit = 0; 771 d->step = metadata_digest_transcribe_writeset; 772 773 return 0; 774 } 775 776 static int metadata_digest_start(struct era_metadata *md, struct digest *d) 777 { 778 if (d->step) 779 return 0; 780 781 memset(d, 0, sizeof(*d)); 782 d->step = metadata_digest_lookup_writeset; 783 784 return 0; 785 } 786 787 /*---------------------------------------------------------------- 788 * High level metadata interface. Target methods should use these, and not 789 * the lower level ones. 790 *--------------------------------------------------------------*/ 791 static struct era_metadata *metadata_open(struct block_device *bdev, 792 sector_t block_size, 793 bool may_format) 794 { 795 int r; 796 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL); 797 798 if (!md) 799 return NULL; 800 801 md->bdev = bdev; 802 md->block_size = block_size; 803 804 md->writesets[0].md.root = INVALID_WRITESET_ROOT; 805 md->writesets[1].md.root = INVALID_WRITESET_ROOT; 806 md->current_writeset = &md->writesets[0]; 807 808 r = create_persistent_data_objects(md, may_format); 809 if (r) { 810 kfree(md); 811 return ERR_PTR(r); 812 } 813 814 return md; 815 } 816 817 static void metadata_close(struct era_metadata *md) 818 { 819 writeset_free(&md->writesets[0]); 820 writeset_free(&md->writesets[1]); 821 destroy_persistent_data_objects(md); 822 kfree(md); 823 } 824 825 static bool valid_nr_blocks(dm_block_t n) 826 { 827 /* 828 * dm_bitset restricts us to 2^32. test_bit & co. restrict us 829 * further to 2^31 - 1 830 */ 831 return n < (1ull << 31); 832 } 833 834 static int metadata_resize(struct era_metadata *md, void *arg) 835 { 836 int r; 837 dm_block_t *new_size = arg; 838 __le32 value; 839 840 if (!valid_nr_blocks(*new_size)) { 841 DMERR("Invalid number of origin blocks %llu", 842 (unsigned long long) *new_size); 843 return -EINVAL; 844 } 845 846 writeset_free(&md->writesets[0]); 847 writeset_free(&md->writesets[1]); 848 849 r = writeset_alloc(&md->writesets[0], *new_size); 850 if (r) { 851 DMERR("%s: writeset_alloc failed for writeset 0", __func__); 852 return r; 853 } 854 855 r = writeset_alloc(&md->writesets[1], *new_size); 856 if (r) { 857 DMERR("%s: writeset_alloc failed for writeset 1", __func__); 858 writeset_free(&md->writesets[0]); 859 return r; 860 } 861 862 value = cpu_to_le32(0u); 863 __dm_bless_for_disk(&value); 864 r = dm_array_resize(&md->era_array_info, md->era_array_root, 865 md->nr_blocks, *new_size, 866 &value, &md->era_array_root); 867 if (r) { 868 DMERR("%s: dm_array_resize failed", __func__); 869 writeset_free(&md->writesets[0]); 870 writeset_free(&md->writesets[1]); 871 return r; 872 } 873 874 md->nr_blocks = *new_size; 875 return 0; 876 } 877 878 static int metadata_era_archive(struct era_metadata *md) 879 { 880 int r; 881 uint64_t keys[1]; 882 struct writeset_disk value; 883 884 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root, 885 &md->current_writeset->md.root); 886 if (r) { 887 DMERR("%s: dm_bitset_flush failed", __func__); 888 return r; 889 } 890 891 ws_pack(&md->current_writeset->md, &value); 892 893 keys[0] = md->current_era; 894 __dm_bless_for_disk(&value); 895 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root, 896 keys, &value, &md->writeset_tree_root); 897 if (r) { 898 DMERR("%s: couldn't insert writeset into btree", __func__); 899 /* FIXME: fail mode */ 900 return r; 901 } 902 903 md->current_writeset->md.root = INVALID_WRITESET_ROOT; 904 md->archived_writesets = true; 905 906 return 0; 907 } 908 909 static struct writeset *next_writeset(struct era_metadata *md) 910 { 911 return (md->current_writeset == &md->writesets[0]) ? 912 &md->writesets[1] : &md->writesets[0]; 913 } 914 915 static int metadata_new_era(struct era_metadata *md) 916 { 917 int r; 918 struct writeset *new_writeset = next_writeset(md); 919 920 r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks); 921 if (r) { 922 DMERR("%s: writeset_init failed", __func__); 923 return r; 924 } 925 926 swap_writeset(md, new_writeset); 927 md->current_era++; 928 929 return 0; 930 } 931 932 static int metadata_era_rollover(struct era_metadata *md) 933 { 934 int r; 935 936 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) { 937 r = metadata_era_archive(md); 938 if (r) { 939 DMERR("%s: metadata_archive_era failed", __func__); 940 /* FIXME: fail mode? */ 941 return r; 942 } 943 } 944 945 r = metadata_new_era(md); 946 if (r) { 947 DMERR("%s: new era failed", __func__); 948 /* FIXME: fail mode */ 949 return r; 950 } 951 952 return 0; 953 } 954 955 static bool metadata_current_marked(struct era_metadata *md, dm_block_t block) 956 { 957 bool r; 958 struct writeset *ws; 959 960 rcu_read_lock(); 961 ws = rcu_dereference(md->current_writeset); 962 r = writeset_marked(ws, block); 963 rcu_read_unlock(); 964 965 return r; 966 } 967 968 static int metadata_commit(struct era_metadata *md) 969 { 970 int r; 971 struct dm_block *sblock; 972 973 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) { 974 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root, 975 &md->current_writeset->md.root); 976 if (r) { 977 DMERR("%s: bitset flush failed", __func__); 978 return r; 979 } 980 } 981 982 r = dm_tm_pre_commit(md->tm); 983 if (r) { 984 DMERR("%s: pre commit failed", __func__); 985 return r; 986 } 987 988 r = save_sm_root(md); 989 if (r) { 990 DMERR("%s: save_sm_root failed", __func__); 991 return r; 992 } 993 994 r = superblock_lock(md, &sblock); 995 if (r) { 996 DMERR("%s: superblock lock failed", __func__); 997 return r; 998 } 999 1000 prepare_superblock(md, dm_block_data(sblock)); 1001 1002 return dm_tm_commit(md->tm, sblock); 1003 } 1004 1005 static int metadata_checkpoint(struct era_metadata *md) 1006 { 1007 /* 1008 * For now we just rollover, but later I want to put a check in to 1009 * avoid this if the filter is still pretty fresh. 1010 */ 1011 return metadata_era_rollover(md); 1012 } 1013 1014 /* 1015 * Metadata snapshots allow userland to access era data. 1016 */ 1017 static int metadata_take_snap(struct era_metadata *md) 1018 { 1019 int r, inc; 1020 struct dm_block *clone; 1021 1022 if (md->metadata_snap != SUPERBLOCK_LOCATION) { 1023 DMERR("%s: metadata snapshot already exists", __func__); 1024 return -EINVAL; 1025 } 1026 1027 r = metadata_era_rollover(md); 1028 if (r) { 1029 DMERR("%s: era rollover failed", __func__); 1030 return r; 1031 } 1032 1033 r = metadata_commit(md); 1034 if (r) { 1035 DMERR("%s: pre commit failed", __func__); 1036 return r; 1037 } 1038 1039 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION); 1040 if (r) { 1041 DMERR("%s: couldn't increment superblock", __func__); 1042 return r; 1043 } 1044 1045 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION, 1046 &sb_validator, &clone, &inc); 1047 if (r) { 1048 DMERR("%s: couldn't shadow superblock", __func__); 1049 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION); 1050 return r; 1051 } 1052 BUG_ON(!inc); 1053 1054 r = dm_sm_inc_block(md->sm, md->writeset_tree_root); 1055 if (r) { 1056 DMERR("%s: couldn't inc writeset tree root", __func__); 1057 dm_tm_unlock(md->tm, clone); 1058 return r; 1059 } 1060 1061 r = dm_sm_inc_block(md->sm, md->era_array_root); 1062 if (r) { 1063 DMERR("%s: couldn't inc era tree root", __func__); 1064 dm_sm_dec_block(md->sm, md->writeset_tree_root); 1065 dm_tm_unlock(md->tm, clone); 1066 return r; 1067 } 1068 1069 md->metadata_snap = dm_block_location(clone); 1070 1071 dm_tm_unlock(md->tm, clone); 1072 1073 return 0; 1074 } 1075 1076 static int metadata_drop_snap(struct era_metadata *md) 1077 { 1078 int r; 1079 dm_block_t location; 1080 struct dm_block *clone; 1081 struct superblock_disk *disk; 1082 1083 if (md->metadata_snap == SUPERBLOCK_LOCATION) { 1084 DMERR("%s: no snap to drop", __func__); 1085 return -EINVAL; 1086 } 1087 1088 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone); 1089 if (r) { 1090 DMERR("%s: couldn't read lock superblock clone", __func__); 1091 return r; 1092 } 1093 1094 /* 1095 * Whatever happens now we'll commit with no record of the metadata 1096 * snap. 1097 */ 1098 md->metadata_snap = SUPERBLOCK_LOCATION; 1099 1100 disk = dm_block_data(clone); 1101 r = dm_btree_del(&md->writeset_tree_info, 1102 le64_to_cpu(disk->writeset_tree_root)); 1103 if (r) { 1104 DMERR("%s: error deleting writeset tree clone", __func__); 1105 dm_tm_unlock(md->tm, clone); 1106 return r; 1107 } 1108 1109 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root)); 1110 if (r) { 1111 DMERR("%s: error deleting era array clone", __func__); 1112 dm_tm_unlock(md->tm, clone); 1113 return r; 1114 } 1115 1116 location = dm_block_location(clone); 1117 dm_tm_unlock(md->tm, clone); 1118 1119 return dm_sm_dec_block(md->sm, location); 1120 } 1121 1122 struct metadata_stats { 1123 dm_block_t used; 1124 dm_block_t total; 1125 dm_block_t snap; 1126 uint32_t era; 1127 }; 1128 1129 static int metadata_get_stats(struct era_metadata *md, void *ptr) 1130 { 1131 int r; 1132 struct metadata_stats *s = ptr; 1133 dm_block_t nr_free, nr_total; 1134 1135 r = dm_sm_get_nr_free(md->sm, &nr_free); 1136 if (r) { 1137 DMERR("dm_sm_get_nr_free returned %d", r); 1138 return r; 1139 } 1140 1141 r = dm_sm_get_nr_blocks(md->sm, &nr_total); 1142 if (r) { 1143 DMERR("dm_pool_get_metadata_dev_size returned %d", r); 1144 return r; 1145 } 1146 1147 s->used = nr_total - nr_free; 1148 s->total = nr_total; 1149 s->snap = md->metadata_snap; 1150 s->era = md->current_era; 1151 1152 return 0; 1153 } 1154 1155 /*----------------------------------------------------------------*/ 1156 1157 struct era { 1158 struct dm_target *ti; 1159 1160 struct dm_dev *metadata_dev; 1161 struct dm_dev *origin_dev; 1162 1163 dm_block_t nr_blocks; 1164 uint32_t sectors_per_block; 1165 int sectors_per_block_shift; 1166 struct era_metadata *md; 1167 1168 struct workqueue_struct *wq; 1169 struct work_struct worker; 1170 1171 spinlock_t deferred_lock; 1172 struct bio_list deferred_bios; 1173 1174 spinlock_t rpc_lock; 1175 struct list_head rpc_calls; 1176 1177 struct digest digest; 1178 atomic_t suspended; 1179 }; 1180 1181 struct rpc { 1182 struct list_head list; 1183 1184 int (*fn0)(struct era_metadata *); 1185 int (*fn1)(struct era_metadata *, void *); 1186 void *arg; 1187 int result; 1188 1189 struct completion complete; 1190 }; 1191 1192 /*---------------------------------------------------------------- 1193 * Remapping. 1194 *---------------------------------------------------------------*/ 1195 static bool block_size_is_power_of_two(struct era *era) 1196 { 1197 return era->sectors_per_block_shift >= 0; 1198 } 1199 1200 static dm_block_t get_block(struct era *era, struct bio *bio) 1201 { 1202 sector_t block_nr = bio->bi_iter.bi_sector; 1203 1204 if (!block_size_is_power_of_two(era)) 1205 (void) sector_div(block_nr, era->sectors_per_block); 1206 else 1207 block_nr >>= era->sectors_per_block_shift; 1208 1209 return block_nr; 1210 } 1211 1212 static void remap_to_origin(struct era *era, struct bio *bio) 1213 { 1214 bio_set_dev(bio, era->origin_dev->bdev); 1215 } 1216 1217 /*---------------------------------------------------------------- 1218 * Worker thread 1219 *--------------------------------------------------------------*/ 1220 static void wake_worker(struct era *era) 1221 { 1222 if (!atomic_read(&era->suspended)) 1223 queue_work(era->wq, &era->worker); 1224 } 1225 1226 static void process_old_eras(struct era *era) 1227 { 1228 int r; 1229 1230 if (!era->digest.step) 1231 return; 1232 1233 r = era->digest.step(era->md, &era->digest); 1234 if (r < 0) { 1235 DMERR("%s: digest step failed, stopping digestion", __func__); 1236 era->digest.step = NULL; 1237 1238 } else if (era->digest.step) 1239 wake_worker(era); 1240 } 1241 1242 static void process_deferred_bios(struct era *era) 1243 { 1244 int r; 1245 struct bio_list deferred_bios, marked_bios; 1246 struct bio *bio; 1247 struct blk_plug plug; 1248 bool commit_needed = false; 1249 bool failed = false; 1250 struct writeset *ws = era->md->current_writeset; 1251 1252 bio_list_init(&deferred_bios); 1253 bio_list_init(&marked_bios); 1254 1255 spin_lock(&era->deferred_lock); 1256 bio_list_merge(&deferred_bios, &era->deferred_bios); 1257 bio_list_init(&era->deferred_bios); 1258 spin_unlock(&era->deferred_lock); 1259 1260 if (bio_list_empty(&deferred_bios)) 1261 return; 1262 1263 while ((bio = bio_list_pop(&deferred_bios))) { 1264 r = writeset_test_and_set(&era->md->bitset_info, ws, 1265 get_block(era, bio)); 1266 if (r < 0) { 1267 /* 1268 * This is bad news, we need to rollback. 1269 * FIXME: finish. 1270 */ 1271 failed = true; 1272 } else if (r == 0) 1273 commit_needed = true; 1274 1275 bio_list_add(&marked_bios, bio); 1276 } 1277 1278 if (commit_needed) { 1279 r = metadata_commit(era->md); 1280 if (r) 1281 failed = true; 1282 } 1283 1284 if (failed) 1285 while ((bio = bio_list_pop(&marked_bios))) 1286 bio_io_error(bio); 1287 else { 1288 blk_start_plug(&plug); 1289 while ((bio = bio_list_pop(&marked_bios))) { 1290 /* 1291 * Only update the in-core writeset if the on-disk one 1292 * was updated too. 1293 */ 1294 if (commit_needed) 1295 set_bit(get_block(era, bio), ws->bits); 1296 submit_bio_noacct(bio); 1297 } 1298 blk_finish_plug(&plug); 1299 } 1300 } 1301 1302 static void process_rpc_calls(struct era *era) 1303 { 1304 int r; 1305 bool need_commit = false; 1306 struct list_head calls; 1307 struct rpc *rpc, *tmp; 1308 1309 INIT_LIST_HEAD(&calls); 1310 spin_lock(&era->rpc_lock); 1311 list_splice_init(&era->rpc_calls, &calls); 1312 spin_unlock(&era->rpc_lock); 1313 1314 list_for_each_entry_safe(rpc, tmp, &calls, list) { 1315 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg); 1316 need_commit = true; 1317 } 1318 1319 if (need_commit) { 1320 r = metadata_commit(era->md); 1321 if (r) 1322 list_for_each_entry_safe(rpc, tmp, &calls, list) 1323 rpc->result = r; 1324 } 1325 1326 list_for_each_entry_safe(rpc, tmp, &calls, list) 1327 complete(&rpc->complete); 1328 } 1329 1330 static void kick_off_digest(struct era *era) 1331 { 1332 if (era->md->archived_writesets) { 1333 era->md->archived_writesets = false; 1334 metadata_digest_start(era->md, &era->digest); 1335 } 1336 } 1337 1338 static void do_work(struct work_struct *ws) 1339 { 1340 struct era *era = container_of(ws, struct era, worker); 1341 1342 kick_off_digest(era); 1343 process_old_eras(era); 1344 process_deferred_bios(era); 1345 process_rpc_calls(era); 1346 } 1347 1348 static void defer_bio(struct era *era, struct bio *bio) 1349 { 1350 spin_lock(&era->deferred_lock); 1351 bio_list_add(&era->deferred_bios, bio); 1352 spin_unlock(&era->deferred_lock); 1353 1354 wake_worker(era); 1355 } 1356 1357 /* 1358 * Make an rpc call to the worker to change the metadata. 1359 */ 1360 static int perform_rpc(struct era *era, struct rpc *rpc) 1361 { 1362 rpc->result = 0; 1363 init_completion(&rpc->complete); 1364 1365 spin_lock(&era->rpc_lock); 1366 list_add(&rpc->list, &era->rpc_calls); 1367 spin_unlock(&era->rpc_lock); 1368 1369 wake_worker(era); 1370 wait_for_completion(&rpc->complete); 1371 1372 return rpc->result; 1373 } 1374 1375 static int in_worker0(struct era *era, int (*fn)(struct era_metadata *)) 1376 { 1377 struct rpc rpc; 1378 rpc.fn0 = fn; 1379 rpc.fn1 = NULL; 1380 1381 return perform_rpc(era, &rpc); 1382 } 1383 1384 static int in_worker1(struct era *era, 1385 int (*fn)(struct era_metadata *, void *), void *arg) 1386 { 1387 struct rpc rpc; 1388 rpc.fn0 = NULL; 1389 rpc.fn1 = fn; 1390 rpc.arg = arg; 1391 1392 return perform_rpc(era, &rpc); 1393 } 1394 1395 static void start_worker(struct era *era) 1396 { 1397 atomic_set(&era->suspended, 0); 1398 } 1399 1400 static void stop_worker(struct era *era) 1401 { 1402 atomic_set(&era->suspended, 1); 1403 drain_workqueue(era->wq); 1404 } 1405 1406 /*---------------------------------------------------------------- 1407 * Target methods 1408 *--------------------------------------------------------------*/ 1409 static void era_destroy(struct era *era) 1410 { 1411 if (era->md) 1412 metadata_close(era->md); 1413 1414 if (era->wq) 1415 destroy_workqueue(era->wq); 1416 1417 if (era->origin_dev) 1418 dm_put_device(era->ti, era->origin_dev); 1419 1420 if (era->metadata_dev) 1421 dm_put_device(era->ti, era->metadata_dev); 1422 1423 kfree(era); 1424 } 1425 1426 static dm_block_t calc_nr_blocks(struct era *era) 1427 { 1428 return dm_sector_div_up(era->ti->len, era->sectors_per_block); 1429 } 1430 1431 static bool valid_block_size(dm_block_t block_size) 1432 { 1433 bool greater_than_zero = block_size > 0; 1434 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0; 1435 1436 return greater_than_zero && multiple_of_min_block_size; 1437 } 1438 1439 /* 1440 * <metadata dev> <data dev> <data block size (sectors)> 1441 */ 1442 static int era_ctr(struct dm_target *ti, unsigned argc, char **argv) 1443 { 1444 int r; 1445 char dummy; 1446 struct era *era; 1447 struct era_metadata *md; 1448 1449 if (argc != 3) { 1450 ti->error = "Invalid argument count"; 1451 return -EINVAL; 1452 } 1453 1454 era = kzalloc(sizeof(*era), GFP_KERNEL); 1455 if (!era) { 1456 ti->error = "Error allocating era structure"; 1457 return -ENOMEM; 1458 } 1459 1460 era->ti = ti; 1461 1462 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev); 1463 if (r) { 1464 ti->error = "Error opening metadata device"; 1465 era_destroy(era); 1466 return -EINVAL; 1467 } 1468 1469 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev); 1470 if (r) { 1471 ti->error = "Error opening data device"; 1472 era_destroy(era); 1473 return -EINVAL; 1474 } 1475 1476 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy); 1477 if (r != 1) { 1478 ti->error = "Error parsing block size"; 1479 era_destroy(era); 1480 return -EINVAL; 1481 } 1482 1483 r = dm_set_target_max_io_len(ti, era->sectors_per_block); 1484 if (r) { 1485 ti->error = "could not set max io len"; 1486 era_destroy(era); 1487 return -EINVAL; 1488 } 1489 1490 if (!valid_block_size(era->sectors_per_block)) { 1491 ti->error = "Invalid block size"; 1492 era_destroy(era); 1493 return -EINVAL; 1494 } 1495 if (era->sectors_per_block & (era->sectors_per_block - 1)) 1496 era->sectors_per_block_shift = -1; 1497 else 1498 era->sectors_per_block_shift = __ffs(era->sectors_per_block); 1499 1500 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true); 1501 if (IS_ERR(md)) { 1502 ti->error = "Error reading metadata"; 1503 era_destroy(era); 1504 return PTR_ERR(md); 1505 } 1506 era->md = md; 1507 1508 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); 1509 if (!era->wq) { 1510 ti->error = "could not create workqueue for metadata object"; 1511 era_destroy(era); 1512 return -ENOMEM; 1513 } 1514 INIT_WORK(&era->worker, do_work); 1515 1516 spin_lock_init(&era->deferred_lock); 1517 bio_list_init(&era->deferred_bios); 1518 1519 spin_lock_init(&era->rpc_lock); 1520 INIT_LIST_HEAD(&era->rpc_calls); 1521 1522 ti->private = era; 1523 ti->num_flush_bios = 1; 1524 ti->flush_supported = true; 1525 1526 ti->num_discard_bios = 1; 1527 1528 return 0; 1529 } 1530 1531 static void era_dtr(struct dm_target *ti) 1532 { 1533 era_destroy(ti->private); 1534 } 1535 1536 static int era_map(struct dm_target *ti, struct bio *bio) 1537 { 1538 struct era *era = ti->private; 1539 dm_block_t block = get_block(era, bio); 1540 1541 /* 1542 * All bios get remapped to the origin device. We do this now, but 1543 * it may not get issued until later. Depending on whether the 1544 * block is marked in this era. 1545 */ 1546 remap_to_origin(era, bio); 1547 1548 /* 1549 * REQ_PREFLUSH bios carry no data, so we're not interested in them. 1550 */ 1551 if (!(bio->bi_opf & REQ_PREFLUSH) && 1552 (bio_data_dir(bio) == WRITE) && 1553 !metadata_current_marked(era->md, block)) { 1554 defer_bio(era, bio); 1555 return DM_MAPIO_SUBMITTED; 1556 } 1557 1558 return DM_MAPIO_REMAPPED; 1559 } 1560 1561 static void era_postsuspend(struct dm_target *ti) 1562 { 1563 int r; 1564 struct era *era = ti->private; 1565 1566 r = in_worker0(era, metadata_era_archive); 1567 if (r) { 1568 DMERR("%s: couldn't archive current era", __func__); 1569 /* FIXME: fail mode */ 1570 } 1571 1572 stop_worker(era); 1573 1574 r = metadata_commit(era->md); 1575 if (r) { 1576 DMERR("%s: metadata_commit failed", __func__); 1577 /* FIXME: fail mode */ 1578 } 1579 } 1580 1581 static int era_preresume(struct dm_target *ti) 1582 { 1583 int r; 1584 struct era *era = ti->private; 1585 dm_block_t new_size = calc_nr_blocks(era); 1586 1587 if (era->nr_blocks != new_size) { 1588 r = metadata_resize(era->md, &new_size); 1589 if (r) { 1590 DMERR("%s: metadata_resize failed", __func__); 1591 return r; 1592 } 1593 1594 r = metadata_commit(era->md); 1595 if (r) { 1596 DMERR("%s: metadata_commit failed", __func__); 1597 return r; 1598 } 1599 1600 era->nr_blocks = new_size; 1601 } 1602 1603 start_worker(era); 1604 1605 r = in_worker0(era, metadata_era_rollover); 1606 if (r) { 1607 DMERR("%s: metadata_era_rollover failed", __func__); 1608 return r; 1609 } 1610 1611 return 0; 1612 } 1613 1614 /* 1615 * Status format: 1616 * 1617 * <metadata block size> <#used metadata blocks>/<#total metadata blocks> 1618 * <current era> <held metadata root | '-'> 1619 */ 1620 static void era_status(struct dm_target *ti, status_type_t type, 1621 unsigned status_flags, char *result, unsigned maxlen) 1622 { 1623 int r; 1624 struct era *era = ti->private; 1625 ssize_t sz = 0; 1626 struct metadata_stats stats; 1627 char buf[BDEVNAME_SIZE]; 1628 1629 switch (type) { 1630 case STATUSTYPE_INFO: 1631 r = in_worker1(era, metadata_get_stats, &stats); 1632 if (r) 1633 goto err; 1634 1635 DMEMIT("%u %llu/%llu %u", 1636 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT), 1637 (unsigned long long) stats.used, 1638 (unsigned long long) stats.total, 1639 (unsigned) stats.era); 1640 1641 if (stats.snap != SUPERBLOCK_LOCATION) 1642 DMEMIT(" %llu", stats.snap); 1643 else 1644 DMEMIT(" -"); 1645 break; 1646 1647 case STATUSTYPE_TABLE: 1648 format_dev_t(buf, era->metadata_dev->bdev->bd_dev); 1649 DMEMIT("%s ", buf); 1650 format_dev_t(buf, era->origin_dev->bdev->bd_dev); 1651 DMEMIT("%s %u", buf, era->sectors_per_block); 1652 break; 1653 1654 case STATUSTYPE_IMA: 1655 *result = '\0'; 1656 break; 1657 } 1658 1659 return; 1660 1661 err: 1662 DMEMIT("Error"); 1663 } 1664 1665 static int era_message(struct dm_target *ti, unsigned argc, char **argv, 1666 char *result, unsigned maxlen) 1667 { 1668 struct era *era = ti->private; 1669 1670 if (argc != 1) { 1671 DMERR("incorrect number of message arguments"); 1672 return -EINVAL; 1673 } 1674 1675 if (!strcasecmp(argv[0], "checkpoint")) 1676 return in_worker0(era, metadata_checkpoint); 1677 1678 if (!strcasecmp(argv[0], "take_metadata_snap")) 1679 return in_worker0(era, metadata_take_snap); 1680 1681 if (!strcasecmp(argv[0], "drop_metadata_snap")) 1682 return in_worker0(era, metadata_drop_snap); 1683 1684 DMERR("unsupported message '%s'", argv[0]); 1685 return -EINVAL; 1686 } 1687 1688 static sector_t get_dev_size(struct dm_dev *dev) 1689 { 1690 return bdev_nr_sectors(dev->bdev); 1691 } 1692 1693 static int era_iterate_devices(struct dm_target *ti, 1694 iterate_devices_callout_fn fn, void *data) 1695 { 1696 struct era *era = ti->private; 1697 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data); 1698 } 1699 1700 static void era_io_hints(struct dm_target *ti, struct queue_limits *limits) 1701 { 1702 struct era *era = ti->private; 1703 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; 1704 1705 /* 1706 * If the system-determined stacked limits are compatible with the 1707 * era device's blocksize (io_opt is a factor) do not override them. 1708 */ 1709 if (io_opt_sectors < era->sectors_per_block || 1710 do_div(io_opt_sectors, era->sectors_per_block)) { 1711 blk_limits_io_min(limits, 0); 1712 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT); 1713 } 1714 } 1715 1716 /*----------------------------------------------------------------*/ 1717 1718 static struct target_type era_target = { 1719 .name = "era", 1720 .version = {1, 0, 0}, 1721 .module = THIS_MODULE, 1722 .ctr = era_ctr, 1723 .dtr = era_dtr, 1724 .map = era_map, 1725 .postsuspend = era_postsuspend, 1726 .preresume = era_preresume, 1727 .status = era_status, 1728 .message = era_message, 1729 .iterate_devices = era_iterate_devices, 1730 .io_hints = era_io_hints 1731 }; 1732 1733 static int __init dm_era_init(void) 1734 { 1735 int r; 1736 1737 r = dm_register_target(&era_target); 1738 if (r) { 1739 DMERR("era target registration failed: %d", r); 1740 return r; 1741 } 1742 1743 return 0; 1744 } 1745 1746 static void __exit dm_era_exit(void) 1747 { 1748 dm_unregister_target(&era_target); 1749 } 1750 1751 module_init(dm_era_init); 1752 module_exit(dm_era_exit); 1753 1754 MODULE_DESCRIPTION(DM_NAME " era target"); 1755 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); 1756 MODULE_LICENSE("GPL"); 1757