1 /* 2 * Copyright (C) 2011 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm-space-map-common.h" 8 #include "dm-transaction-manager.h" 9 10 #include <linux/bitops.h> 11 #include <linux/device-mapper.h> 12 13 #define DM_MSG_PREFIX "space map common" 14 15 /*----------------------------------------------------------------*/ 16 17 /* 18 * Index validator. 19 */ 20 #define INDEX_CSUM_XOR 160478 21 22 static void index_prepare_for_write(struct dm_block_validator *v, 23 struct dm_block *b, 24 size_t block_size) 25 { 26 struct disk_metadata_index *mi_le = dm_block_data(b); 27 28 mi_le->blocknr = cpu_to_le64(dm_block_location(b)); 29 mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding, 30 block_size - sizeof(__le32), 31 INDEX_CSUM_XOR)); 32 } 33 34 static int index_check(struct dm_block_validator *v, 35 struct dm_block *b, 36 size_t block_size) 37 { 38 struct disk_metadata_index *mi_le = dm_block_data(b); 39 __le32 csum_disk; 40 41 if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) { 42 DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu", 43 le64_to_cpu(mi_le->blocknr), dm_block_location(b)); 44 return -ENOTBLK; 45 } 46 47 csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding, 48 block_size - sizeof(__le32), 49 INDEX_CSUM_XOR)); 50 if (csum_disk != mi_le->csum) { 51 DMERR_LIMIT("index_check failed: csum %u != wanted %u", 52 le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum)); 53 return -EILSEQ; 54 } 55 56 return 0; 57 } 58 59 static struct dm_block_validator index_validator = { 60 .name = "index", 61 .prepare_for_write = index_prepare_for_write, 62 .check = index_check 63 }; 64 65 /*----------------------------------------------------------------*/ 66 67 /* 68 * Bitmap validator 69 */ 70 #define BITMAP_CSUM_XOR 240779 71 72 static void bitmap_prepare_for_write(struct dm_block_validator *v, 73 struct dm_block *b, 74 size_t block_size) 75 { 76 struct disk_bitmap_header *disk_header = dm_block_data(b); 77 78 disk_header->blocknr = cpu_to_le64(dm_block_location(b)); 79 disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, 80 block_size - sizeof(__le32), 81 BITMAP_CSUM_XOR)); 82 } 83 84 static int bitmap_check(struct dm_block_validator *v, 85 struct dm_block *b, 86 size_t block_size) 87 { 88 struct disk_bitmap_header *disk_header = dm_block_data(b); 89 __le32 csum_disk; 90 91 if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) { 92 DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu", 93 le64_to_cpu(disk_header->blocknr), dm_block_location(b)); 94 return -ENOTBLK; 95 } 96 97 csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, 98 block_size - sizeof(__le32), 99 BITMAP_CSUM_XOR)); 100 if (csum_disk != disk_header->csum) { 101 DMERR_LIMIT("bitmap check failed: csum %u != wanted %u", 102 le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum)); 103 return -EILSEQ; 104 } 105 106 return 0; 107 } 108 109 static struct dm_block_validator dm_sm_bitmap_validator = { 110 .name = "sm_bitmap", 111 .prepare_for_write = bitmap_prepare_for_write, 112 .check = bitmap_check 113 }; 114 115 /*----------------------------------------------------------------*/ 116 117 #define ENTRIES_PER_WORD 32 118 #define ENTRIES_SHIFT 5 119 120 static void *dm_bitmap_data(struct dm_block *b) 121 { 122 return dm_block_data(b) + sizeof(struct disk_bitmap_header); 123 } 124 125 #define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL 126 127 static unsigned bitmap_word_used(void *addr, unsigned b) 128 { 129 __le64 *words_le = addr; 130 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); 131 132 uint64_t bits = le64_to_cpu(*w_le); 133 uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH; 134 135 return !(~bits & mask); 136 } 137 138 static unsigned sm_lookup_bitmap(void *addr, unsigned b) 139 { 140 __le64 *words_le = addr; 141 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); 142 unsigned hi, lo; 143 144 b = (b & (ENTRIES_PER_WORD - 1)) << 1; 145 hi = !!test_bit_le(b, (void *) w_le); 146 lo = !!test_bit_le(b + 1, (void *) w_le); 147 return (hi << 1) | lo; 148 } 149 150 static void sm_set_bitmap(void *addr, unsigned b, unsigned val) 151 { 152 __le64 *words_le = addr; 153 __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); 154 155 b = (b & (ENTRIES_PER_WORD - 1)) << 1; 156 157 if (val & 2) 158 __set_bit_le(b, (void *) w_le); 159 else 160 __clear_bit_le(b, (void *) w_le); 161 162 if (val & 1) 163 __set_bit_le(b + 1, (void *) w_le); 164 else 165 __clear_bit_le(b + 1, (void *) w_le); 166 } 167 168 static int sm_find_free(void *addr, unsigned begin, unsigned end, 169 unsigned *result) 170 { 171 while (begin < end) { 172 if (!(begin & (ENTRIES_PER_WORD - 1)) && 173 bitmap_word_used(addr, begin)) { 174 begin += ENTRIES_PER_WORD; 175 continue; 176 } 177 178 if (!sm_lookup_bitmap(addr, begin)) { 179 *result = begin; 180 return 0; 181 } 182 183 begin++; 184 } 185 186 return -ENOSPC; 187 } 188 189 /*----------------------------------------------------------------*/ 190 191 static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm) 192 { 193 ll->tm = tm; 194 195 ll->bitmap_info.tm = tm; 196 ll->bitmap_info.levels = 1; 197 198 /* 199 * Because the new bitmap blocks are created via a shadow 200 * operation, the old entry has already had its reference count 201 * decremented and we don't need the btree to do any bookkeeping. 202 */ 203 ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry); 204 ll->bitmap_info.value_type.inc = NULL; 205 ll->bitmap_info.value_type.dec = NULL; 206 ll->bitmap_info.value_type.equal = NULL; 207 208 ll->ref_count_info.tm = tm; 209 ll->ref_count_info.levels = 1; 210 ll->ref_count_info.value_type.size = sizeof(uint32_t); 211 ll->ref_count_info.value_type.inc = NULL; 212 ll->ref_count_info.value_type.dec = NULL; 213 ll->ref_count_info.value_type.equal = NULL; 214 215 ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm)); 216 217 if (ll->block_size > (1 << 30)) { 218 DMERR("block size too big to hold bitmaps"); 219 return -EINVAL; 220 } 221 222 ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) * 223 ENTRIES_PER_BYTE; 224 ll->nr_blocks = 0; 225 ll->bitmap_root = 0; 226 ll->ref_count_root = 0; 227 ll->bitmap_index_changed = false; 228 229 return 0; 230 } 231 232 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks) 233 { 234 int r; 235 dm_block_t i, nr_blocks, nr_indexes; 236 unsigned old_blocks, blocks; 237 238 nr_blocks = ll->nr_blocks + extra_blocks; 239 old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block); 240 blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block); 241 242 nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block); 243 if (nr_indexes > ll->max_entries(ll)) { 244 DMERR("space map too large"); 245 return -EINVAL; 246 } 247 248 /* 249 * We need to set this before the dm_tm_new_block() call below. 250 */ 251 ll->nr_blocks = nr_blocks; 252 for (i = old_blocks; i < blocks; i++) { 253 struct dm_block *b; 254 struct disk_index_entry idx; 255 256 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b); 257 if (r < 0) 258 return r; 259 260 idx.blocknr = cpu_to_le64(dm_block_location(b)); 261 262 dm_tm_unlock(ll->tm, b); 263 264 idx.nr_free = cpu_to_le32(ll->entries_per_block); 265 idx.none_free_before = 0; 266 267 r = ll->save_ie(ll, i, &idx); 268 if (r < 0) 269 return r; 270 } 271 272 return 0; 273 } 274 275 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result) 276 { 277 int r; 278 dm_block_t index = b; 279 struct disk_index_entry ie_disk; 280 struct dm_block *blk; 281 282 b = do_div(index, ll->entries_per_block); 283 r = ll->load_ie(ll, index, &ie_disk); 284 if (r < 0) 285 return r; 286 287 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), 288 &dm_sm_bitmap_validator, &blk); 289 if (r < 0) 290 return r; 291 292 *result = sm_lookup_bitmap(dm_bitmap_data(blk), b); 293 294 dm_tm_unlock(ll->tm, blk); 295 296 return 0; 297 } 298 299 static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b, 300 uint32_t *result) 301 { 302 __le32 le_rc; 303 int r; 304 305 r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc); 306 if (r < 0) 307 return r; 308 309 *result = le32_to_cpu(le_rc); 310 311 return r; 312 } 313 314 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) 315 { 316 int r = sm_ll_lookup_bitmap(ll, b, result); 317 318 if (r) 319 return r; 320 321 if (*result != 3) 322 return r; 323 324 return sm_ll_lookup_big_ref_count(ll, b, result); 325 } 326 327 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, 328 dm_block_t end, dm_block_t *result) 329 { 330 int r; 331 struct disk_index_entry ie_disk; 332 dm_block_t i, index_begin = begin; 333 dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block); 334 335 /* 336 * FIXME: Use shifts 337 */ 338 begin = do_div(index_begin, ll->entries_per_block); 339 end = do_div(end, ll->entries_per_block); 340 341 for (i = index_begin; i < index_end; i++, begin = 0) { 342 struct dm_block *blk; 343 unsigned position; 344 uint32_t bit_end; 345 346 r = ll->load_ie(ll, i, &ie_disk); 347 if (r < 0) 348 return r; 349 350 if (le32_to_cpu(ie_disk.nr_free) == 0) 351 continue; 352 353 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), 354 &dm_sm_bitmap_validator, &blk); 355 if (r < 0) 356 return r; 357 358 bit_end = (i == index_end - 1) ? end : ll->entries_per_block; 359 360 r = sm_find_free(dm_bitmap_data(blk), 361 max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)), 362 bit_end, &position); 363 if (r == -ENOSPC) { 364 /* 365 * This might happen because we started searching 366 * part way through the bitmap. 367 */ 368 dm_tm_unlock(ll->tm, blk); 369 continue; 370 371 } else if (r < 0) { 372 dm_tm_unlock(ll->tm, blk); 373 return r; 374 } 375 376 dm_tm_unlock(ll->tm, blk); 377 378 *result = i * ll->entries_per_block + (dm_block_t) position; 379 return 0; 380 } 381 382 return -ENOSPC; 383 } 384 385 static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b, 386 int (*mutator)(void *context, uint32_t old, uint32_t *new), 387 void *context, enum allocation_event *ev) 388 { 389 int r; 390 uint32_t bit, old, ref_count; 391 struct dm_block *nb; 392 dm_block_t index = b; 393 struct disk_index_entry ie_disk; 394 void *bm_le; 395 int inc; 396 397 bit = do_div(index, ll->entries_per_block); 398 r = ll->load_ie(ll, index, &ie_disk); 399 if (r < 0) 400 return r; 401 402 r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr), 403 &dm_sm_bitmap_validator, &nb, &inc); 404 if (r < 0) { 405 DMERR("dm_tm_shadow_block() failed"); 406 return r; 407 } 408 ie_disk.blocknr = cpu_to_le64(dm_block_location(nb)); 409 410 bm_le = dm_bitmap_data(nb); 411 old = sm_lookup_bitmap(bm_le, bit); 412 413 if (old > 2) { 414 r = sm_ll_lookup_big_ref_count(ll, b, &old); 415 if (r < 0) { 416 dm_tm_unlock(ll->tm, nb); 417 return r; 418 } 419 } 420 421 r = mutator(context, old, &ref_count); 422 if (r) { 423 dm_tm_unlock(ll->tm, nb); 424 return r; 425 } 426 427 if (ref_count <= 2) { 428 sm_set_bitmap(bm_le, bit, ref_count); 429 430 dm_tm_unlock(ll->tm, nb); 431 432 if (old > 2) { 433 r = dm_btree_remove(&ll->ref_count_info, 434 ll->ref_count_root, 435 &b, &ll->ref_count_root); 436 if (r) 437 return r; 438 } 439 440 } else { 441 __le32 le_rc = cpu_to_le32(ref_count); 442 443 sm_set_bitmap(bm_le, bit, 3); 444 dm_tm_unlock(ll->tm, nb); 445 446 __dm_bless_for_disk(&le_rc); 447 r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root, 448 &b, &le_rc, &ll->ref_count_root); 449 if (r < 0) { 450 DMERR("ref count insert failed"); 451 return r; 452 } 453 } 454 455 if (ref_count && !old) { 456 *ev = SM_ALLOC; 457 ll->nr_allocated++; 458 le32_add_cpu(&ie_disk.nr_free, -1); 459 if (le32_to_cpu(ie_disk.none_free_before) == bit) 460 ie_disk.none_free_before = cpu_to_le32(bit + 1); 461 462 } else if (old && !ref_count) { 463 *ev = SM_FREE; 464 ll->nr_allocated--; 465 le32_add_cpu(&ie_disk.nr_free, 1); 466 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit)); 467 } 468 469 return ll->save_ie(ll, index, &ie_disk); 470 } 471 472 static int set_ref_count(void *context, uint32_t old, uint32_t *new) 473 { 474 *new = *((uint32_t *) context); 475 return 0; 476 } 477 478 int sm_ll_insert(struct ll_disk *ll, dm_block_t b, 479 uint32_t ref_count, enum allocation_event *ev) 480 { 481 return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev); 482 } 483 484 static int inc_ref_count(void *context, uint32_t old, uint32_t *new) 485 { 486 *new = old + 1; 487 return 0; 488 } 489 490 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) 491 { 492 return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev); 493 } 494 495 static int dec_ref_count(void *context, uint32_t old, uint32_t *new) 496 { 497 if (!old) { 498 DMERR_LIMIT("unable to decrement a reference count below 0"); 499 return -EINVAL; 500 } 501 502 *new = old - 1; 503 return 0; 504 } 505 506 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) 507 { 508 return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev); 509 } 510 511 int sm_ll_commit(struct ll_disk *ll) 512 { 513 int r = 0; 514 515 if (ll->bitmap_index_changed) { 516 r = ll->commit(ll); 517 if (!r) 518 ll->bitmap_index_changed = false; 519 } 520 521 return r; 522 } 523 524 /*----------------------------------------------------------------*/ 525 526 static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index, 527 struct disk_index_entry *ie) 528 { 529 memcpy(ie, ll->mi_le.index + index, sizeof(*ie)); 530 return 0; 531 } 532 533 static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index, 534 struct disk_index_entry *ie) 535 { 536 ll->bitmap_index_changed = true; 537 memcpy(ll->mi_le.index + index, ie, sizeof(*ie)); 538 return 0; 539 } 540 541 static int metadata_ll_init_index(struct ll_disk *ll) 542 { 543 int r; 544 struct dm_block *b; 545 546 r = dm_tm_new_block(ll->tm, &index_validator, &b); 547 if (r < 0) 548 return r; 549 550 memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); 551 ll->bitmap_root = dm_block_location(b); 552 553 dm_tm_unlock(ll->tm, b); 554 555 return 0; 556 } 557 558 static int metadata_ll_open(struct ll_disk *ll) 559 { 560 int r; 561 struct dm_block *block; 562 563 r = dm_tm_read_lock(ll->tm, ll->bitmap_root, 564 &index_validator, &block); 565 if (r) 566 return r; 567 568 memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le)); 569 dm_tm_unlock(ll->tm, block); 570 571 return 0; 572 } 573 574 static dm_block_t metadata_ll_max_entries(struct ll_disk *ll) 575 { 576 return MAX_METADATA_BITMAPS; 577 } 578 579 static int metadata_ll_commit(struct ll_disk *ll) 580 { 581 int r, inc; 582 struct dm_block *b; 583 584 r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc); 585 if (r) 586 return r; 587 588 memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); 589 ll->bitmap_root = dm_block_location(b); 590 591 dm_tm_unlock(ll->tm, b); 592 593 return 0; 594 } 595 596 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm) 597 { 598 int r; 599 600 r = sm_ll_init(ll, tm); 601 if (r < 0) 602 return r; 603 604 ll->load_ie = metadata_ll_load_ie; 605 ll->save_ie = metadata_ll_save_ie; 606 ll->init_index = metadata_ll_init_index; 607 ll->open_index = metadata_ll_open; 608 ll->max_entries = metadata_ll_max_entries; 609 ll->commit = metadata_ll_commit; 610 611 ll->nr_blocks = 0; 612 ll->nr_allocated = 0; 613 614 r = ll->init_index(ll); 615 if (r < 0) 616 return r; 617 618 r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); 619 if (r < 0) 620 return r; 621 622 return 0; 623 } 624 625 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, 626 void *root_le, size_t len) 627 { 628 int r; 629 struct disk_sm_root *smr = root_le; 630 631 if (len < sizeof(struct disk_sm_root)) { 632 DMERR("sm_metadata root too small"); 633 return -ENOMEM; 634 } 635 636 r = sm_ll_init(ll, tm); 637 if (r < 0) 638 return r; 639 640 ll->load_ie = metadata_ll_load_ie; 641 ll->save_ie = metadata_ll_save_ie; 642 ll->init_index = metadata_ll_init_index; 643 ll->open_index = metadata_ll_open; 644 ll->max_entries = metadata_ll_max_entries; 645 ll->commit = metadata_ll_commit; 646 647 ll->nr_blocks = le64_to_cpu(smr->nr_blocks); 648 ll->nr_allocated = le64_to_cpu(smr->nr_allocated); 649 ll->bitmap_root = le64_to_cpu(smr->bitmap_root); 650 ll->ref_count_root = le64_to_cpu(smr->ref_count_root); 651 652 return ll->open_index(ll); 653 } 654 655 /*----------------------------------------------------------------*/ 656 657 static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index, 658 struct disk_index_entry *ie) 659 { 660 return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie); 661 } 662 663 static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index, 664 struct disk_index_entry *ie) 665 { 666 __dm_bless_for_disk(ie); 667 return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root, 668 &index, ie, &ll->bitmap_root); 669 } 670 671 static int disk_ll_init_index(struct ll_disk *ll) 672 { 673 return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root); 674 } 675 676 static int disk_ll_open(struct ll_disk *ll) 677 { 678 /* nothing to do */ 679 return 0; 680 } 681 682 static dm_block_t disk_ll_max_entries(struct ll_disk *ll) 683 { 684 return -1ULL; 685 } 686 687 static int disk_ll_commit(struct ll_disk *ll) 688 { 689 return 0; 690 } 691 692 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm) 693 { 694 int r; 695 696 r = sm_ll_init(ll, tm); 697 if (r < 0) 698 return r; 699 700 ll->load_ie = disk_ll_load_ie; 701 ll->save_ie = disk_ll_save_ie; 702 ll->init_index = disk_ll_init_index; 703 ll->open_index = disk_ll_open; 704 ll->max_entries = disk_ll_max_entries; 705 ll->commit = disk_ll_commit; 706 707 ll->nr_blocks = 0; 708 ll->nr_allocated = 0; 709 710 r = ll->init_index(ll); 711 if (r < 0) 712 return r; 713 714 r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); 715 if (r < 0) 716 return r; 717 718 return 0; 719 } 720 721 int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm, 722 void *root_le, size_t len) 723 { 724 int r; 725 struct disk_sm_root *smr = root_le; 726 727 if (len < sizeof(struct disk_sm_root)) { 728 DMERR("sm_metadata root too small"); 729 return -ENOMEM; 730 } 731 732 r = sm_ll_init(ll, tm); 733 if (r < 0) 734 return r; 735 736 ll->load_ie = disk_ll_load_ie; 737 ll->save_ie = disk_ll_save_ie; 738 ll->init_index = disk_ll_init_index; 739 ll->open_index = disk_ll_open; 740 ll->max_entries = disk_ll_max_entries; 741 ll->commit = disk_ll_commit; 742 743 ll->nr_blocks = le64_to_cpu(smr->nr_blocks); 744 ll->nr_allocated = le64_to_cpu(smr->nr_allocated); 745 ll->bitmap_root = le64_to_cpu(smr->bitmap_root); 746 ll->ref_count_root = le64_to_cpu(smr->ref_count_root); 747 748 return ll->open_index(ll); 749 } 750 751 /*----------------------------------------------------------------*/ 752