1 /* 2 * Block driver for the QCOW version 2 format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25 #include "qemu-common.h" 26 #include "block/block_int.h" 27 #include "block/qcow2.h" 28 29 static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size); 30 static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, 31 int64_t offset, int64_t length, 32 int addend, enum qcow2_discard_type type); 33 34 35 /*********************************************************/ 36 /* refcount handling */ 37 38 int qcow2_refcount_init(BlockDriverState *bs) 39 { 40 BDRVQcowState *s = bs->opaque; 41 int ret, refcount_table_size2, i; 42 43 refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); 44 s->refcount_table = g_malloc(refcount_table_size2); 45 if (s->refcount_table_size > 0) { 46 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); 47 ret = bdrv_pread(bs->file, s->refcount_table_offset, 48 s->refcount_table, refcount_table_size2); 49 if (ret != refcount_table_size2) 50 goto fail; 51 for(i = 0; i < s->refcount_table_size; i++) 52 be64_to_cpus(&s->refcount_table[i]); 53 } 54 return 0; 55 fail: 56 return -ENOMEM; 57 } 58 59 void qcow2_refcount_close(BlockDriverState *bs) 60 { 61 BDRVQcowState *s = bs->opaque; 62 g_free(s->refcount_table); 63 } 64 65 66 static int load_refcount_block(BlockDriverState *bs, 67 int64_t refcount_block_offset, 68 void **refcount_block) 69 { 70 BDRVQcowState *s = bs->opaque; 71 int ret; 72 73 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); 74 ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, 75 refcount_block); 76 77 return ret; 78 } 79 80 /* 81 * Returns the refcount of the cluster given by its index. Any non-negative 82 * return value is the refcount of the cluster, negative values are -errno 83 * and indicate an error. 84 */ 85 static int get_refcount(BlockDriverState *bs, int64_t cluster_index) 86 { 87 BDRVQcowState *s = bs->opaque; 88 int refcount_table_index, block_index; 89 int64_t refcount_block_offset; 90 int ret; 91 uint16_t *refcount_block; 92 uint16_t refcount; 93 94 refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); 95 if (refcount_table_index >= s->refcount_table_size) 96 return 0; 97 refcount_block_offset = s->refcount_table[refcount_table_index]; 98 if (!refcount_block_offset) 99 return 0; 100 101 ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, 102 (void**) &refcount_block); 103 if (ret < 0) { 104 return ret; 105 } 106 107 block_index = cluster_index & 108 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); 109 refcount = be16_to_cpu(refcount_block[block_index]); 110 111 ret = qcow2_cache_put(bs, s->refcount_block_cache, 112 (void**) &refcount_block); 113 if (ret < 0) { 114 return ret; 115 } 116 117 return refcount; 118 } 119 120 /* 121 * Rounds the refcount table size up to avoid growing the table for each single 122 * refcount block that is allocated. 123 */ 124 static unsigned int next_refcount_table_size(BDRVQcowState *s, 125 unsigned int min_size) 126 { 127 unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; 128 unsigned int refcount_table_clusters = 129 MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); 130 131 while (min_clusters > refcount_table_clusters) { 132 refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; 133 } 134 135 return refcount_table_clusters << (s->cluster_bits - 3); 136 } 137 138 139 /* Checks if two offsets are described by the same refcount block */ 140 static int in_same_refcount_block(BDRVQcowState *s, uint64_t offset_a, 141 uint64_t offset_b) 142 { 143 uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT); 144 uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT); 145 146 return (block_a == block_b); 147 } 148 149 /* 150 * Loads a refcount block. If it doesn't exist yet, it is allocated first 151 * (including growing the refcount table if needed). 152 * 153 * Returns 0 on success or -errno in error case 154 */ 155 static int alloc_refcount_block(BlockDriverState *bs, 156 int64_t cluster_index, uint16_t **refcount_block) 157 { 158 BDRVQcowState *s = bs->opaque; 159 unsigned int refcount_table_index; 160 int ret; 161 162 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 163 164 /* Find the refcount block for the given cluster */ 165 refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); 166 167 if (refcount_table_index < s->refcount_table_size) { 168 169 uint64_t refcount_block_offset = 170 s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; 171 172 /* If it's already there, we're done */ 173 if (refcount_block_offset) { 174 return load_refcount_block(bs, refcount_block_offset, 175 (void**) refcount_block); 176 } 177 } 178 179 /* 180 * If we came here, we need to allocate something. Something is at least 181 * a cluster for the new refcount block. It may also include a new refcount 182 * table if the old refcount table is too small. 183 * 184 * Note that allocating clusters here needs some special care: 185 * 186 * - We can't use the normal qcow2_alloc_clusters(), it would try to 187 * increase the refcount and very likely we would end up with an endless 188 * recursion. Instead we must place the refcount blocks in a way that 189 * they can describe them themselves. 190 * 191 * - We need to consider that at this point we are inside update_refcounts 192 * and doing the initial refcount increase. This means that some clusters 193 * have already been allocated by the caller, but their refcount isn't 194 * accurate yet. free_cluster_index tells us where this allocation ends 195 * as long as we don't overwrite it by freeing clusters. 196 * 197 * - alloc_clusters_noref and qcow2_free_clusters may load a different 198 * refcount block into the cache 199 */ 200 201 *refcount_block = NULL; 202 203 /* We write to the refcount table, so we might depend on L2 tables */ 204 ret = qcow2_cache_flush(bs, s->l2_table_cache); 205 if (ret < 0) { 206 return ret; 207 } 208 209 /* Allocate the refcount block itself and mark it as used */ 210 int64_t new_block = alloc_clusters_noref(bs, s->cluster_size); 211 if (new_block < 0) { 212 return new_block; 213 } 214 215 #ifdef DEBUG_ALLOC2 216 fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64 217 " at %" PRIx64 "\n", 218 refcount_table_index, cluster_index << s->cluster_bits, new_block); 219 #endif 220 221 if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) { 222 /* Zero the new refcount block before updating it */ 223 ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, 224 (void**) refcount_block); 225 if (ret < 0) { 226 goto fail_block; 227 } 228 229 memset(*refcount_block, 0, s->cluster_size); 230 231 /* The block describes itself, need to update the cache */ 232 int block_index = (new_block >> s->cluster_bits) & 233 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); 234 (*refcount_block)[block_index] = cpu_to_be16(1); 235 } else { 236 /* Described somewhere else. This can recurse at most twice before we 237 * arrive at a block that describes itself. */ 238 ret = update_refcount(bs, new_block, s->cluster_size, 1, 239 QCOW2_DISCARD_NEVER); 240 if (ret < 0) { 241 goto fail_block; 242 } 243 244 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 245 if (ret < 0) { 246 goto fail_block; 247 } 248 249 /* Initialize the new refcount block only after updating its refcount, 250 * update_refcount uses the refcount cache itself */ 251 ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, 252 (void**) refcount_block); 253 if (ret < 0) { 254 goto fail_block; 255 } 256 257 memset(*refcount_block, 0, s->cluster_size); 258 } 259 260 /* Now the new refcount block needs to be written to disk */ 261 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); 262 qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block); 263 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 264 if (ret < 0) { 265 goto fail_block; 266 } 267 268 /* If the refcount table is big enough, just hook the block up there */ 269 if (refcount_table_index < s->refcount_table_size) { 270 uint64_t data64 = cpu_to_be64(new_block); 271 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); 272 ret = bdrv_pwrite_sync(bs->file, 273 s->refcount_table_offset + refcount_table_index * sizeof(uint64_t), 274 &data64, sizeof(data64)); 275 if (ret < 0) { 276 goto fail_block; 277 } 278 279 s->refcount_table[refcount_table_index] = new_block; 280 return 0; 281 } 282 283 ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block); 284 if (ret < 0) { 285 goto fail_block; 286 } 287 288 /* 289 * If we come here, we need to grow the refcount table. Again, a new 290 * refcount table needs some space and we can't simply allocate to avoid 291 * endless recursion. 292 * 293 * Therefore let's grab new refcount blocks at the end of the image, which 294 * will describe themselves and the new refcount table. This way we can 295 * reference them only in the new table and do the switch to the new 296 * refcount table at once without producing an inconsistent state in 297 * between. 298 */ 299 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); 300 301 /* Calculate the number of refcount blocks needed so far */ 302 uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT); 303 uint64_t blocks_used = (s->free_cluster_index + 304 refcount_block_clusters - 1) / refcount_block_clusters; 305 306 /* And now we need at least one block more for the new metadata */ 307 uint64_t table_size = next_refcount_table_size(s, blocks_used + 1); 308 uint64_t last_table_size; 309 uint64_t blocks_clusters; 310 do { 311 uint64_t table_clusters = 312 size_to_clusters(s, table_size * sizeof(uint64_t)); 313 blocks_clusters = 1 + 314 ((table_clusters + refcount_block_clusters - 1) 315 / refcount_block_clusters); 316 uint64_t meta_clusters = table_clusters + blocks_clusters; 317 318 last_table_size = table_size; 319 table_size = next_refcount_table_size(s, blocks_used + 320 ((meta_clusters + refcount_block_clusters - 1) 321 / refcount_block_clusters)); 322 323 } while (last_table_size != table_size); 324 325 #ifdef DEBUG_ALLOC2 326 fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", 327 s->refcount_table_size, table_size); 328 #endif 329 330 /* Create the new refcount table and blocks */ 331 uint64_t meta_offset = (blocks_used * refcount_block_clusters) * 332 s->cluster_size; 333 uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; 334 uint16_t *new_blocks = g_malloc0(blocks_clusters * s->cluster_size); 335 uint64_t *new_table = g_malloc0(table_size * sizeof(uint64_t)); 336 337 assert(meta_offset >= (s->free_cluster_index * s->cluster_size)); 338 339 /* Fill the new refcount table */ 340 memcpy(new_table, s->refcount_table, 341 s->refcount_table_size * sizeof(uint64_t)); 342 new_table[refcount_table_index] = new_block; 343 344 int i; 345 for (i = 0; i < blocks_clusters; i++) { 346 new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); 347 } 348 349 /* Fill the refcount blocks */ 350 uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t)); 351 int block = 0; 352 for (i = 0; i < table_clusters + blocks_clusters; i++) { 353 new_blocks[block++] = cpu_to_be16(1); 354 } 355 356 /* Write refcount blocks to disk */ 357 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); 358 ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks, 359 blocks_clusters * s->cluster_size); 360 g_free(new_blocks); 361 if (ret < 0) { 362 goto fail_table; 363 } 364 365 /* Write refcount table to disk */ 366 for(i = 0; i < table_size; i++) { 367 cpu_to_be64s(&new_table[i]); 368 } 369 370 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); 371 ret = bdrv_pwrite_sync(bs->file, table_offset, new_table, 372 table_size * sizeof(uint64_t)); 373 if (ret < 0) { 374 goto fail_table; 375 } 376 377 for(i = 0; i < table_size; i++) { 378 be64_to_cpus(&new_table[i]); 379 } 380 381 /* Hook up the new refcount table in the qcow2 header */ 382 uint8_t data[12]; 383 cpu_to_be64w((uint64_t*)data, table_offset); 384 cpu_to_be32w((uint32_t*)(data + 8), table_clusters); 385 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); 386 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset), 387 data, sizeof(data)); 388 if (ret < 0) { 389 goto fail_table; 390 } 391 392 /* And switch it in memory */ 393 uint64_t old_table_offset = s->refcount_table_offset; 394 uint64_t old_table_size = s->refcount_table_size; 395 396 g_free(s->refcount_table); 397 s->refcount_table = new_table; 398 s->refcount_table_size = table_size; 399 s->refcount_table_offset = table_offset; 400 401 /* Free old table. Remember, we must not change free_cluster_index */ 402 uint64_t old_free_cluster_index = s->free_cluster_index; 403 qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t), 404 QCOW2_DISCARD_OTHER); 405 s->free_cluster_index = old_free_cluster_index; 406 407 ret = load_refcount_block(bs, new_block, (void**) refcount_block); 408 if (ret < 0) { 409 return ret; 410 } 411 412 return 0; 413 414 fail_table: 415 g_free(new_table); 416 fail_block: 417 if (*refcount_block != NULL) { 418 qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block); 419 } 420 return ret; 421 } 422 423 void qcow2_process_discards(BlockDriverState *bs, int ret) 424 { 425 BDRVQcowState *s = bs->opaque; 426 Qcow2DiscardRegion *d, *next; 427 428 QTAILQ_FOREACH_SAFE(d, &s->discards, next, next) { 429 QTAILQ_REMOVE(&s->discards, d, next); 430 431 /* Discard is optional, ignore the return value */ 432 if (ret >= 0) { 433 bdrv_discard(bs->file, 434 d->offset >> BDRV_SECTOR_BITS, 435 d->bytes >> BDRV_SECTOR_BITS); 436 } 437 438 g_free(d); 439 } 440 } 441 442 static void update_refcount_discard(BlockDriverState *bs, 443 uint64_t offset, uint64_t length) 444 { 445 BDRVQcowState *s = bs->opaque; 446 Qcow2DiscardRegion *d, *p, *next; 447 448 QTAILQ_FOREACH(d, &s->discards, next) { 449 uint64_t new_start = MIN(offset, d->offset); 450 uint64_t new_end = MAX(offset + length, d->offset + d->bytes); 451 452 if (new_end - new_start <= length + d->bytes) { 453 /* There can't be any overlap, areas ending up here have no 454 * references any more and therefore shouldn't get freed another 455 * time. */ 456 assert(d->bytes + length == new_end - new_start); 457 d->offset = new_start; 458 d->bytes = new_end - new_start; 459 goto found; 460 } 461 } 462 463 d = g_malloc(sizeof(*d)); 464 *d = (Qcow2DiscardRegion) { 465 .bs = bs, 466 .offset = offset, 467 .bytes = length, 468 }; 469 QTAILQ_INSERT_TAIL(&s->discards, d, next); 470 471 found: 472 /* Merge discard requests if they are adjacent now */ 473 QTAILQ_FOREACH_SAFE(p, &s->discards, next, next) { 474 if (p == d 475 || p->offset > d->offset + d->bytes 476 || d->offset > p->offset + p->bytes) 477 { 478 continue; 479 } 480 481 /* Still no overlap possible */ 482 assert(p->offset == d->offset + d->bytes 483 || d->offset == p->offset + p->bytes); 484 485 QTAILQ_REMOVE(&s->discards, p, next); 486 d->offset = MIN(d->offset, p->offset); 487 d->bytes += p->bytes; 488 } 489 } 490 491 /* XXX: cache several refcount block clusters ? */ 492 static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, 493 int64_t offset, int64_t length, int addend, enum qcow2_discard_type type) 494 { 495 BDRVQcowState *s = bs->opaque; 496 int64_t start, last, cluster_offset; 497 uint16_t *refcount_block = NULL; 498 int64_t old_table_index = -1; 499 int ret; 500 501 #ifdef DEBUG_ALLOC2 502 fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", 503 offset, length, addend); 504 #endif 505 if (length < 0) { 506 return -EINVAL; 507 } else if (length == 0) { 508 return 0; 509 } 510 511 if (addend < 0) { 512 qcow2_cache_set_dependency(bs, s->refcount_block_cache, 513 s->l2_table_cache); 514 } 515 516 start = offset & ~(s->cluster_size - 1); 517 last = (offset + length - 1) & ~(s->cluster_size - 1); 518 for(cluster_offset = start; cluster_offset <= last; 519 cluster_offset += s->cluster_size) 520 { 521 int block_index, refcount; 522 int64_t cluster_index = cluster_offset >> s->cluster_bits; 523 int64_t table_index = 524 cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); 525 526 /* Load the refcount block and allocate it if needed */ 527 if (table_index != old_table_index) { 528 if (refcount_block) { 529 ret = qcow2_cache_put(bs, s->refcount_block_cache, 530 (void**) &refcount_block); 531 if (ret < 0) { 532 goto fail; 533 } 534 } 535 536 ret = alloc_refcount_block(bs, cluster_index, &refcount_block); 537 if (ret < 0) { 538 goto fail; 539 } 540 } 541 old_table_index = table_index; 542 543 qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block); 544 545 /* we can update the count and save it */ 546 block_index = cluster_index & 547 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); 548 549 refcount = be16_to_cpu(refcount_block[block_index]); 550 refcount += addend; 551 if (refcount < 0 || refcount > 0xffff) { 552 ret = -EINVAL; 553 goto fail; 554 } 555 if (refcount == 0 && cluster_index < s->free_cluster_index) { 556 s->free_cluster_index = cluster_index; 557 } 558 refcount_block[block_index] = cpu_to_be16(refcount); 559 560 if (refcount == 0 && s->discard_passthrough[type]) { 561 update_refcount_discard(bs, cluster_offset, s->cluster_size); 562 } 563 } 564 565 ret = 0; 566 fail: 567 if (!s->cache_discards) { 568 qcow2_process_discards(bs, ret); 569 } 570 571 /* Write last changed block to disk */ 572 if (refcount_block) { 573 int wret; 574 wret = qcow2_cache_put(bs, s->refcount_block_cache, 575 (void**) &refcount_block); 576 if (wret < 0) { 577 return ret < 0 ? ret : wret; 578 } 579 } 580 581 /* 582 * Try do undo any updates if an error is returned (This may succeed in 583 * some cases like ENOSPC for allocating a new refcount block) 584 */ 585 if (ret < 0) { 586 int dummy; 587 dummy = update_refcount(bs, offset, cluster_offset - offset, -addend, 588 QCOW2_DISCARD_NEVER); 589 (void)dummy; 590 } 591 592 return ret; 593 } 594 595 /* 596 * Increases or decreases the refcount of a given cluster by one. 597 * addend must be 1 or -1. 598 * 599 * If the return value is non-negative, it is the new refcount of the cluster. 600 * If it is negative, it is -errno and indicates an error. 601 */ 602 static int update_cluster_refcount(BlockDriverState *bs, 603 int64_t cluster_index, 604 int addend, 605 enum qcow2_discard_type type) 606 { 607 BDRVQcowState *s = bs->opaque; 608 int ret; 609 610 ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend, 611 type); 612 if (ret < 0) { 613 return ret; 614 } 615 616 return get_refcount(bs, cluster_index); 617 } 618 619 620 621 /*********************************************************/ 622 /* cluster allocation functions */ 623 624 625 626 /* return < 0 if error */ 627 static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) 628 { 629 BDRVQcowState *s = bs->opaque; 630 int i, nb_clusters, refcount; 631 632 nb_clusters = size_to_clusters(s, size); 633 retry: 634 for(i = 0; i < nb_clusters; i++) { 635 int64_t next_cluster_index = s->free_cluster_index++; 636 refcount = get_refcount(bs, next_cluster_index); 637 638 if (refcount < 0) { 639 return refcount; 640 } else if (refcount != 0) { 641 goto retry; 642 } 643 } 644 #ifdef DEBUG_ALLOC2 645 fprintf(stderr, "alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", 646 size, 647 (s->free_cluster_index - nb_clusters) << s->cluster_bits); 648 #endif 649 return (s->free_cluster_index - nb_clusters) << s->cluster_bits; 650 } 651 652 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) 653 { 654 int64_t offset; 655 int ret; 656 657 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 658 offset = alloc_clusters_noref(bs, size); 659 if (offset < 0) { 660 return offset; 661 } 662 663 ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER); 664 if (ret < 0) { 665 return ret; 666 } 667 668 return offset; 669 } 670 671 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, 672 int nb_clusters) 673 { 674 BDRVQcowState *s = bs->opaque; 675 uint64_t cluster_index; 676 uint64_t old_free_cluster_index; 677 int i, refcount, ret; 678 679 /* Check how many clusters there are free */ 680 cluster_index = offset >> s->cluster_bits; 681 for(i = 0; i < nb_clusters; i++) { 682 refcount = get_refcount(bs, cluster_index++); 683 684 if (refcount < 0) { 685 return refcount; 686 } else if (refcount != 0) { 687 break; 688 } 689 } 690 691 /* And then allocate them */ 692 old_free_cluster_index = s->free_cluster_index; 693 s->free_cluster_index = cluster_index + i; 694 695 ret = update_refcount(bs, offset, i << s->cluster_bits, 1, 696 QCOW2_DISCARD_NEVER); 697 if (ret < 0) { 698 return ret; 699 } 700 701 s->free_cluster_index = old_free_cluster_index; 702 703 return i; 704 } 705 706 /* only used to allocate compressed sectors. We try to allocate 707 contiguous sectors. size must be <= cluster_size */ 708 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) 709 { 710 BDRVQcowState *s = bs->opaque; 711 int64_t offset, cluster_offset; 712 int free_in_cluster; 713 714 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); 715 assert(size > 0 && size <= s->cluster_size); 716 if (s->free_byte_offset == 0) { 717 offset = qcow2_alloc_clusters(bs, s->cluster_size); 718 if (offset < 0) { 719 return offset; 720 } 721 s->free_byte_offset = offset; 722 } 723 redo: 724 free_in_cluster = s->cluster_size - 725 (s->free_byte_offset & (s->cluster_size - 1)); 726 if (size <= free_in_cluster) { 727 /* enough space in current cluster */ 728 offset = s->free_byte_offset; 729 s->free_byte_offset += size; 730 free_in_cluster -= size; 731 if (free_in_cluster == 0) 732 s->free_byte_offset = 0; 733 if ((offset & (s->cluster_size - 1)) != 0) 734 update_cluster_refcount(bs, offset >> s->cluster_bits, 1, 735 QCOW2_DISCARD_NEVER); 736 } else { 737 offset = qcow2_alloc_clusters(bs, s->cluster_size); 738 if (offset < 0) { 739 return offset; 740 } 741 cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); 742 if ((cluster_offset + s->cluster_size) == offset) { 743 /* we are lucky: contiguous data */ 744 offset = s->free_byte_offset; 745 update_cluster_refcount(bs, offset >> s->cluster_bits, 1, 746 QCOW2_DISCARD_NEVER); 747 s->free_byte_offset += size; 748 } else { 749 s->free_byte_offset = offset; 750 goto redo; 751 } 752 } 753 754 /* The cluster refcount was incremented, either by qcow2_alloc_clusters() 755 * or explicitly by update_cluster_refcount(). Refcount blocks must be 756 * flushed before the caller's L2 table updates. 757 */ 758 qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); 759 return offset; 760 } 761 762 void qcow2_free_clusters(BlockDriverState *bs, 763 int64_t offset, int64_t size, 764 enum qcow2_discard_type type) 765 { 766 int ret; 767 768 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); 769 ret = update_refcount(bs, offset, size, -1, type); 770 if (ret < 0) { 771 fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); 772 /* TODO Remember the clusters to free them later and avoid leaking */ 773 } 774 } 775 776 /* 777 * Free a cluster using its L2 entry (handles clusters of all types, e.g. 778 * normal cluster, compressed cluster, etc.) 779 */ 780 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, 781 int nb_clusters, enum qcow2_discard_type type) 782 { 783 BDRVQcowState *s = bs->opaque; 784 785 switch (qcow2_get_cluster_type(l2_entry)) { 786 case QCOW2_CLUSTER_COMPRESSED: 787 { 788 int nb_csectors; 789 nb_csectors = ((l2_entry >> s->csize_shift) & 790 s->csize_mask) + 1; 791 qcow2_free_clusters(bs, 792 (l2_entry & s->cluster_offset_mask) & ~511, 793 nb_csectors * 512, type); 794 } 795 break; 796 case QCOW2_CLUSTER_NORMAL: 797 qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK, 798 nb_clusters << s->cluster_bits, type); 799 break; 800 case QCOW2_CLUSTER_UNALLOCATED: 801 case QCOW2_CLUSTER_ZERO: 802 break; 803 default: 804 abort(); 805 } 806 } 807 808 809 810 /*********************************************************/ 811 /* snapshots and image creation */ 812 813 814 815 /* update the refcounts of snapshots and the copied flag */ 816 int qcow2_update_snapshot_refcount(BlockDriverState *bs, 817 int64_t l1_table_offset, int l1_size, int addend) 818 { 819 BDRVQcowState *s = bs->opaque; 820 uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; 821 int64_t old_offset, old_l2_offset; 822 int i, j, l1_modified = 0, nb_csectors, refcount; 823 int ret; 824 825 l2_table = NULL; 826 l1_table = NULL; 827 l1_size2 = l1_size * sizeof(uint64_t); 828 829 s->cache_discards = true; 830 831 /* WARNING: qcow2_snapshot_goto relies on this function not using the 832 * l1_table_offset when it is the current s->l1_table_offset! Be careful 833 * when changing this! */ 834 if (l1_table_offset != s->l1_table_offset) { 835 l1_table = g_malloc0(align_offset(l1_size2, 512)); 836 l1_allocated = 1; 837 838 ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2); 839 if (ret < 0) { 840 goto fail; 841 } 842 843 for(i = 0;i < l1_size; i++) 844 be64_to_cpus(&l1_table[i]); 845 } else { 846 assert(l1_size == s->l1_size); 847 l1_table = s->l1_table; 848 l1_allocated = 0; 849 } 850 851 for(i = 0; i < l1_size; i++) { 852 l2_offset = l1_table[i]; 853 if (l2_offset) { 854 old_l2_offset = l2_offset; 855 l2_offset &= L1E_OFFSET_MASK; 856 857 ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, 858 (void**) &l2_table); 859 if (ret < 0) { 860 goto fail; 861 } 862 863 for(j = 0; j < s->l2_size; j++) { 864 uint64_t cluster_index; 865 866 offset = be64_to_cpu(l2_table[j]); 867 old_offset = offset; 868 offset &= ~QCOW_OFLAG_COPIED; 869 870 switch (qcow2_get_cluster_type(offset)) { 871 case QCOW2_CLUSTER_COMPRESSED: 872 nb_csectors = ((offset >> s->csize_shift) & 873 s->csize_mask) + 1; 874 if (addend != 0) { 875 int ret; 876 ret = update_refcount(bs, 877 (offset & s->cluster_offset_mask) & ~511, 878 nb_csectors * 512, addend, 879 QCOW2_DISCARD_SNAPSHOT); 880 if (ret < 0) { 881 goto fail; 882 } 883 } 884 /* compressed clusters are never modified */ 885 refcount = 2; 886 break; 887 888 case QCOW2_CLUSTER_NORMAL: 889 case QCOW2_CLUSTER_ZERO: 890 cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; 891 if (!cluster_index) { 892 /* unallocated */ 893 refcount = 0; 894 break; 895 } 896 if (addend != 0) { 897 refcount = update_cluster_refcount(bs, cluster_index, addend, 898 QCOW2_DISCARD_SNAPSHOT); 899 } else { 900 refcount = get_refcount(bs, cluster_index); 901 } 902 903 if (refcount < 0) { 904 ret = refcount; 905 goto fail; 906 } 907 break; 908 909 case QCOW2_CLUSTER_UNALLOCATED: 910 refcount = 0; 911 break; 912 913 default: 914 abort(); 915 } 916 917 if (refcount == 1) { 918 offset |= QCOW_OFLAG_COPIED; 919 } 920 if (offset != old_offset) { 921 if (addend > 0) { 922 qcow2_cache_set_dependency(bs, s->l2_table_cache, 923 s->refcount_block_cache); 924 } 925 l2_table[j] = cpu_to_be64(offset); 926 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); 927 } 928 } 929 930 ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); 931 if (ret < 0) { 932 goto fail; 933 } 934 935 936 if (addend != 0) { 937 refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend, 938 QCOW2_DISCARD_SNAPSHOT); 939 } else { 940 refcount = get_refcount(bs, l2_offset >> s->cluster_bits); 941 } 942 if (refcount < 0) { 943 ret = refcount; 944 goto fail; 945 } else if (refcount == 1) { 946 l2_offset |= QCOW_OFLAG_COPIED; 947 } 948 if (l2_offset != old_l2_offset) { 949 l1_table[i] = l2_offset; 950 l1_modified = 1; 951 } 952 } 953 } 954 955 ret = bdrv_flush(bs); 956 fail: 957 if (l2_table) { 958 qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); 959 } 960 961 s->cache_discards = false; 962 qcow2_process_discards(bs, ret); 963 964 /* Update L1 only if it isn't deleted anyway (addend = -1) */ 965 if (ret == 0 && addend >= 0 && l1_modified) { 966 for (i = 0; i < l1_size; i++) { 967 cpu_to_be64s(&l1_table[i]); 968 } 969 970 ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2); 971 972 for (i = 0; i < l1_size; i++) { 973 be64_to_cpus(&l1_table[i]); 974 } 975 } 976 if (l1_allocated) 977 g_free(l1_table); 978 return ret; 979 } 980 981 982 983 984 /*********************************************************/ 985 /* refcount checking functions */ 986 987 988 989 /* 990 * Increases the refcount for a range of clusters in a given refcount table. 991 * This is used to construct a temporary refcount table out of L1 and L2 tables 992 * which can be compared the the refcount table saved in the image. 993 * 994 * Modifies the number of errors in res. 995 */ 996 static void inc_refcounts(BlockDriverState *bs, 997 BdrvCheckResult *res, 998 uint16_t *refcount_table, 999 int refcount_table_size, 1000 int64_t offset, int64_t size) 1001 { 1002 BDRVQcowState *s = bs->opaque; 1003 int64_t start, last, cluster_offset; 1004 int k; 1005 1006 if (size <= 0) 1007 return; 1008 1009 start = offset & ~(s->cluster_size - 1); 1010 last = (offset + size - 1) & ~(s->cluster_size - 1); 1011 for(cluster_offset = start; cluster_offset <= last; 1012 cluster_offset += s->cluster_size) { 1013 k = cluster_offset >> s->cluster_bits; 1014 if (k < 0) { 1015 fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", 1016 cluster_offset); 1017 res->corruptions++; 1018 } else if (k >= refcount_table_size) { 1019 fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " 1020 "the end of the image file, can't properly check refcounts.\n", 1021 cluster_offset); 1022 res->check_errors++; 1023 } else { 1024 if (++refcount_table[k] == 0) { 1025 fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 1026 "\n", cluster_offset); 1027 res->corruptions++; 1028 } 1029 } 1030 } 1031 } 1032 1033 /* Flags for check_refcounts_l1() and check_refcounts_l2() */ 1034 enum { 1035 CHECK_OFLAG_COPIED = 0x1, /* check QCOW_OFLAG_COPIED matches refcount */ 1036 CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */ 1037 }; 1038 1039 /* 1040 * Increases the refcount in the given refcount table for the all clusters 1041 * referenced in the L2 table. While doing so, performs some checks on L2 1042 * entries. 1043 * 1044 * Returns the number of errors found by the checks or -errno if an internal 1045 * error occurred. 1046 */ 1047 static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, 1048 uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, 1049 int flags) 1050 { 1051 BDRVQcowState *s = bs->opaque; 1052 uint64_t *l2_table, l2_entry; 1053 uint64_t next_contiguous_offset = 0; 1054 int i, l2_size, nb_csectors, refcount; 1055 1056 /* Read L2 table from disk */ 1057 l2_size = s->l2_size * sizeof(uint64_t); 1058 l2_table = g_malloc(l2_size); 1059 1060 if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) 1061 goto fail; 1062 1063 /* Do the actual checks */ 1064 for(i = 0; i < s->l2_size; i++) { 1065 l2_entry = be64_to_cpu(l2_table[i]); 1066 1067 switch (qcow2_get_cluster_type(l2_entry)) { 1068 case QCOW2_CLUSTER_COMPRESSED: 1069 /* Compressed clusters don't have QCOW_OFLAG_COPIED */ 1070 if (l2_entry & QCOW_OFLAG_COPIED) { 1071 fprintf(stderr, "ERROR: cluster %" PRId64 ": " 1072 "copied flag must never be set for compressed " 1073 "clusters\n", l2_entry >> s->cluster_bits); 1074 l2_entry &= ~QCOW_OFLAG_COPIED; 1075 res->corruptions++; 1076 } 1077 1078 /* Mark cluster as used */ 1079 nb_csectors = ((l2_entry >> s->csize_shift) & 1080 s->csize_mask) + 1; 1081 l2_entry &= s->cluster_offset_mask; 1082 inc_refcounts(bs, res, refcount_table, refcount_table_size, 1083 l2_entry & ~511, nb_csectors * 512); 1084 1085 if (flags & CHECK_FRAG_INFO) { 1086 res->bfi.allocated_clusters++; 1087 res->bfi.compressed_clusters++; 1088 1089 /* Compressed clusters are fragmented by nature. Since they 1090 * take up sub-sector space but we only have sector granularity 1091 * I/O we need to re-read the same sectors even for adjacent 1092 * compressed clusters. 1093 */ 1094 res->bfi.fragmented_clusters++; 1095 } 1096 break; 1097 1098 case QCOW2_CLUSTER_ZERO: 1099 if ((l2_entry & L2E_OFFSET_MASK) == 0) { 1100 break; 1101 } 1102 /* fall through */ 1103 1104 case QCOW2_CLUSTER_NORMAL: 1105 { 1106 /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ 1107 uint64_t offset = l2_entry & L2E_OFFSET_MASK; 1108 1109 if (flags & CHECK_OFLAG_COPIED) { 1110 refcount = get_refcount(bs, offset >> s->cluster_bits); 1111 if (refcount < 0) { 1112 fprintf(stderr, "Can't get refcount for offset %" 1113 PRIx64 ": %s\n", l2_entry, strerror(-refcount)); 1114 goto fail; 1115 } 1116 if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { 1117 fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" 1118 PRIx64 " refcount=%d\n", l2_entry, refcount); 1119 res->corruptions++; 1120 } 1121 } 1122 1123 if (flags & CHECK_FRAG_INFO) { 1124 res->bfi.allocated_clusters++; 1125 if (next_contiguous_offset && 1126 offset != next_contiguous_offset) { 1127 res->bfi.fragmented_clusters++; 1128 } 1129 next_contiguous_offset = offset + s->cluster_size; 1130 } 1131 1132 /* Mark cluster as used */ 1133 inc_refcounts(bs, res, refcount_table,refcount_table_size, 1134 offset, s->cluster_size); 1135 1136 /* Correct offsets are cluster aligned */ 1137 if (offset & (s->cluster_size - 1)) { 1138 fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " 1139 "properly aligned; L2 entry corrupted.\n", offset); 1140 res->corruptions++; 1141 } 1142 break; 1143 } 1144 1145 case QCOW2_CLUSTER_UNALLOCATED: 1146 break; 1147 1148 default: 1149 abort(); 1150 } 1151 } 1152 1153 g_free(l2_table); 1154 return 0; 1155 1156 fail: 1157 fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n"); 1158 g_free(l2_table); 1159 return -EIO; 1160 } 1161 1162 /* 1163 * Increases the refcount for the L1 table, its L2 tables and all referenced 1164 * clusters in the given refcount table. While doing so, performs some checks 1165 * on L1 and L2 entries. 1166 * 1167 * Returns the number of errors found by the checks or -errno if an internal 1168 * error occurred. 1169 */ 1170 static int check_refcounts_l1(BlockDriverState *bs, 1171 BdrvCheckResult *res, 1172 uint16_t *refcount_table, 1173 int refcount_table_size, 1174 int64_t l1_table_offset, int l1_size, 1175 int flags) 1176 { 1177 BDRVQcowState *s = bs->opaque; 1178 uint64_t *l1_table, l2_offset, l1_size2; 1179 int i, refcount, ret; 1180 1181 l1_size2 = l1_size * sizeof(uint64_t); 1182 1183 /* Mark L1 table as used */ 1184 inc_refcounts(bs, res, refcount_table, refcount_table_size, 1185 l1_table_offset, l1_size2); 1186 1187 /* Read L1 table entries from disk */ 1188 if (l1_size2 == 0) { 1189 l1_table = NULL; 1190 } else { 1191 l1_table = g_malloc(l1_size2); 1192 if (bdrv_pread(bs->file, l1_table_offset, 1193 l1_table, l1_size2) != l1_size2) 1194 goto fail; 1195 for(i = 0;i < l1_size; i++) 1196 be64_to_cpus(&l1_table[i]); 1197 } 1198 1199 /* Do the actual checks */ 1200 for(i = 0; i < l1_size; i++) { 1201 l2_offset = l1_table[i]; 1202 if (l2_offset) { 1203 /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ 1204 if (flags & CHECK_OFLAG_COPIED) { 1205 refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) 1206 >> s->cluster_bits); 1207 if (refcount < 0) { 1208 fprintf(stderr, "Can't get refcount for l2_offset %" 1209 PRIx64 ": %s\n", l2_offset, strerror(-refcount)); 1210 goto fail; 1211 } 1212 if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { 1213 fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 1214 " refcount=%d\n", l2_offset, refcount); 1215 res->corruptions++; 1216 } 1217 } 1218 1219 /* Mark L2 table as used */ 1220 l2_offset &= L1E_OFFSET_MASK; 1221 inc_refcounts(bs, res, refcount_table, refcount_table_size, 1222 l2_offset, s->cluster_size); 1223 1224 /* L2 tables are cluster aligned */ 1225 if (l2_offset & (s->cluster_size - 1)) { 1226 fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " 1227 "cluster aligned; L1 entry corrupted\n", l2_offset); 1228 res->corruptions++; 1229 } 1230 1231 /* Process and check L2 entries */ 1232 ret = check_refcounts_l2(bs, res, refcount_table, 1233 refcount_table_size, l2_offset, flags); 1234 if (ret < 0) { 1235 goto fail; 1236 } 1237 } 1238 } 1239 g_free(l1_table); 1240 return 0; 1241 1242 fail: 1243 fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); 1244 res->check_errors++; 1245 g_free(l1_table); 1246 return -EIO; 1247 } 1248 1249 /* 1250 * Checks an image for refcount consistency. 1251 * 1252 * Returns 0 if no errors are found, the number of errors in case the image is 1253 * detected as corrupted, and -errno when an internal error occurred. 1254 */ 1255 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 1256 BdrvCheckMode fix) 1257 { 1258 BDRVQcowState *s = bs->opaque; 1259 int64_t size, i, highest_cluster; 1260 int nb_clusters, refcount1, refcount2; 1261 QCowSnapshot *sn; 1262 uint16_t *refcount_table; 1263 int ret; 1264 1265 size = bdrv_getlength(bs->file); 1266 nb_clusters = size_to_clusters(s, size); 1267 refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t)); 1268 1269 res->bfi.total_clusters = 1270 size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); 1271 1272 /* header */ 1273 inc_refcounts(bs, res, refcount_table, nb_clusters, 1274 0, s->cluster_size); 1275 1276 /* current L1 table */ 1277 ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, 1278 s->l1_table_offset, s->l1_size, 1279 CHECK_OFLAG_COPIED | CHECK_FRAG_INFO); 1280 if (ret < 0) { 1281 goto fail; 1282 } 1283 1284 /* snapshots */ 1285 for(i = 0; i < s->nb_snapshots; i++) { 1286 sn = s->snapshots + i; 1287 ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, 1288 sn->l1_table_offset, sn->l1_size, 0); 1289 if (ret < 0) { 1290 goto fail; 1291 } 1292 } 1293 inc_refcounts(bs, res, refcount_table, nb_clusters, 1294 s->snapshots_offset, s->snapshots_size); 1295 1296 /* refcount data */ 1297 inc_refcounts(bs, res, refcount_table, nb_clusters, 1298 s->refcount_table_offset, 1299 s->refcount_table_size * sizeof(uint64_t)); 1300 1301 for(i = 0; i < s->refcount_table_size; i++) { 1302 uint64_t offset, cluster; 1303 offset = s->refcount_table[i]; 1304 cluster = offset >> s->cluster_bits; 1305 1306 /* Refcount blocks are cluster aligned */ 1307 if (offset & (s->cluster_size - 1)) { 1308 fprintf(stderr, "ERROR refcount block %" PRId64 " is not " 1309 "cluster aligned; refcount table entry corrupted\n", i); 1310 res->corruptions++; 1311 continue; 1312 } 1313 1314 if (cluster >= nb_clusters) { 1315 fprintf(stderr, "ERROR refcount block %" PRId64 1316 " is outside image\n", i); 1317 res->corruptions++; 1318 continue; 1319 } 1320 1321 if (offset != 0) { 1322 inc_refcounts(bs, res, refcount_table, nb_clusters, 1323 offset, s->cluster_size); 1324 if (refcount_table[cluster] != 1) { 1325 fprintf(stderr, "ERROR refcount block %" PRId64 1326 " refcount=%d\n", 1327 i, refcount_table[cluster]); 1328 res->corruptions++; 1329 } 1330 } 1331 } 1332 1333 /* compare ref counts */ 1334 for (i = 0, highest_cluster = 0; i < nb_clusters; i++) { 1335 refcount1 = get_refcount(bs, i); 1336 if (refcount1 < 0) { 1337 fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", 1338 i, strerror(-refcount1)); 1339 res->check_errors++; 1340 continue; 1341 } 1342 1343 refcount2 = refcount_table[i]; 1344 1345 if (refcount1 > 0 || refcount2 > 0) { 1346 highest_cluster = i; 1347 } 1348 1349 if (refcount1 != refcount2) { 1350 1351 /* Check if we're allowed to fix the mismatch */ 1352 int *num_fixed = NULL; 1353 if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) { 1354 num_fixed = &res->leaks_fixed; 1355 } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) { 1356 num_fixed = &res->corruptions_fixed; 1357 } 1358 1359 fprintf(stderr, "%s cluster %" PRId64 " refcount=%d reference=%d\n", 1360 num_fixed != NULL ? "Repairing" : 1361 refcount1 < refcount2 ? "ERROR" : 1362 "Leaked", 1363 i, refcount1, refcount2); 1364 1365 if (num_fixed) { 1366 ret = update_refcount(bs, i << s->cluster_bits, 1, 1367 refcount2 - refcount1, 1368 QCOW2_DISCARD_ALWAYS); 1369 if (ret >= 0) { 1370 (*num_fixed)++; 1371 continue; 1372 } 1373 } 1374 1375 /* And if we couldn't, print an error */ 1376 if (refcount1 < refcount2) { 1377 res->corruptions++; 1378 } else { 1379 res->leaks++; 1380 } 1381 } 1382 } 1383 1384 res->image_end_offset = (highest_cluster + 1) * s->cluster_size; 1385 ret = 0; 1386 1387 fail: 1388 g_free(refcount_table); 1389 1390 return ret; 1391 } 1392 1393