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 offset = be64_to_cpu(l2_table[j]); 865 if (offset != 0) { 866 old_offset = offset; 867 offset &= ~QCOW_OFLAG_COPIED; 868 if (offset & QCOW_OFLAG_COMPRESSED) { 869 nb_csectors = ((offset >> s->csize_shift) & 870 s->csize_mask) + 1; 871 if (addend != 0) { 872 int ret; 873 ret = update_refcount(bs, 874 (offset & s->cluster_offset_mask) & ~511, 875 nb_csectors * 512, addend, 876 QCOW2_DISCARD_SNAPSHOT); 877 if (ret < 0) { 878 goto fail; 879 } 880 } 881 /* compressed clusters are never modified */ 882 refcount = 2; 883 } else { 884 uint64_t cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; 885 if (addend != 0) { 886 refcount = update_cluster_refcount(bs, cluster_index, addend, 887 QCOW2_DISCARD_SNAPSHOT); 888 } else { 889 refcount = get_refcount(bs, cluster_index); 890 } 891 892 if (refcount < 0) { 893 ret = refcount; 894 goto fail; 895 } 896 } 897 898 if (refcount == 1) { 899 offset |= QCOW_OFLAG_COPIED; 900 } 901 if (offset != old_offset) { 902 if (addend > 0) { 903 qcow2_cache_set_dependency(bs, s->l2_table_cache, 904 s->refcount_block_cache); 905 } 906 l2_table[j] = cpu_to_be64(offset); 907 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); 908 } 909 } 910 } 911 912 ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); 913 if (ret < 0) { 914 goto fail; 915 } 916 917 918 if (addend != 0) { 919 refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend, 920 QCOW2_DISCARD_SNAPSHOT); 921 } else { 922 refcount = get_refcount(bs, l2_offset >> s->cluster_bits); 923 } 924 if (refcount < 0) { 925 ret = refcount; 926 goto fail; 927 } else if (refcount == 1) { 928 l2_offset |= QCOW_OFLAG_COPIED; 929 } 930 if (l2_offset != old_l2_offset) { 931 l1_table[i] = l2_offset; 932 l1_modified = 1; 933 } 934 } 935 } 936 937 ret = bdrv_flush(bs); 938 fail: 939 if (l2_table) { 940 qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); 941 } 942 943 s->cache_discards = false; 944 qcow2_process_discards(bs, ret); 945 946 /* Update L1 only if it isn't deleted anyway (addend = -1) */ 947 if (ret == 0 && addend >= 0 && l1_modified) { 948 for (i = 0; i < l1_size; i++) { 949 cpu_to_be64s(&l1_table[i]); 950 } 951 952 ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2); 953 954 for (i = 0; i < l1_size; i++) { 955 be64_to_cpus(&l1_table[i]); 956 } 957 } 958 if (l1_allocated) 959 g_free(l1_table); 960 return ret; 961 } 962 963 964 965 966 /*********************************************************/ 967 /* refcount checking functions */ 968 969 970 971 /* 972 * Increases the refcount for a range of clusters in a given refcount table. 973 * This is used to construct a temporary refcount table out of L1 and L2 tables 974 * which can be compared the the refcount table saved in the image. 975 * 976 * Modifies the number of errors in res. 977 */ 978 static void inc_refcounts(BlockDriverState *bs, 979 BdrvCheckResult *res, 980 uint16_t *refcount_table, 981 int refcount_table_size, 982 int64_t offset, int64_t size) 983 { 984 BDRVQcowState *s = bs->opaque; 985 int64_t start, last, cluster_offset; 986 int k; 987 988 if (size <= 0) 989 return; 990 991 start = offset & ~(s->cluster_size - 1); 992 last = (offset + size - 1) & ~(s->cluster_size - 1); 993 for(cluster_offset = start; cluster_offset <= last; 994 cluster_offset += s->cluster_size) { 995 k = cluster_offset >> s->cluster_bits; 996 if (k < 0) { 997 fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", 998 cluster_offset); 999 res->corruptions++; 1000 } else if (k >= refcount_table_size) { 1001 fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " 1002 "the end of the image file, can't properly check refcounts.\n", 1003 cluster_offset); 1004 res->check_errors++; 1005 } else { 1006 if (++refcount_table[k] == 0) { 1007 fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 1008 "\n", cluster_offset); 1009 res->corruptions++; 1010 } 1011 } 1012 } 1013 } 1014 1015 /* Flags for check_refcounts_l1() and check_refcounts_l2() */ 1016 enum { 1017 CHECK_OFLAG_COPIED = 0x1, /* check QCOW_OFLAG_COPIED matches refcount */ 1018 CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */ 1019 }; 1020 1021 /* 1022 * Increases the refcount in the given refcount table for the all clusters 1023 * referenced in the L2 table. While doing so, performs some checks on L2 1024 * entries. 1025 * 1026 * Returns the number of errors found by the checks or -errno if an internal 1027 * error occurred. 1028 */ 1029 static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, 1030 uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, 1031 int flags) 1032 { 1033 BDRVQcowState *s = bs->opaque; 1034 uint64_t *l2_table, l2_entry; 1035 uint64_t next_contiguous_offset = 0; 1036 int i, l2_size, nb_csectors, refcount; 1037 1038 /* Read L2 table from disk */ 1039 l2_size = s->l2_size * sizeof(uint64_t); 1040 l2_table = g_malloc(l2_size); 1041 1042 if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) 1043 goto fail; 1044 1045 /* Do the actual checks */ 1046 for(i = 0; i < s->l2_size; i++) { 1047 l2_entry = be64_to_cpu(l2_table[i]); 1048 1049 switch (qcow2_get_cluster_type(l2_entry)) { 1050 case QCOW2_CLUSTER_COMPRESSED: 1051 /* Compressed clusters don't have QCOW_OFLAG_COPIED */ 1052 if (l2_entry & QCOW_OFLAG_COPIED) { 1053 fprintf(stderr, "ERROR: cluster %" PRId64 ": " 1054 "copied flag must never be set for compressed " 1055 "clusters\n", l2_entry >> s->cluster_bits); 1056 l2_entry &= ~QCOW_OFLAG_COPIED; 1057 res->corruptions++; 1058 } 1059 1060 /* Mark cluster as used */ 1061 nb_csectors = ((l2_entry >> s->csize_shift) & 1062 s->csize_mask) + 1; 1063 l2_entry &= s->cluster_offset_mask; 1064 inc_refcounts(bs, res, refcount_table, refcount_table_size, 1065 l2_entry & ~511, nb_csectors * 512); 1066 1067 if (flags & CHECK_FRAG_INFO) { 1068 res->bfi.allocated_clusters++; 1069 res->bfi.compressed_clusters++; 1070 1071 /* Compressed clusters are fragmented by nature. Since they 1072 * take up sub-sector space but we only have sector granularity 1073 * I/O we need to re-read the same sectors even for adjacent 1074 * compressed clusters. 1075 */ 1076 res->bfi.fragmented_clusters++; 1077 } 1078 break; 1079 1080 case QCOW2_CLUSTER_ZERO: 1081 if ((l2_entry & L2E_OFFSET_MASK) == 0) { 1082 break; 1083 } 1084 /* fall through */ 1085 1086 case QCOW2_CLUSTER_NORMAL: 1087 { 1088 /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ 1089 uint64_t offset = l2_entry & L2E_OFFSET_MASK; 1090 1091 if (flags & CHECK_OFLAG_COPIED) { 1092 refcount = get_refcount(bs, offset >> s->cluster_bits); 1093 if (refcount < 0) { 1094 fprintf(stderr, "Can't get refcount for offset %" 1095 PRIx64 ": %s\n", l2_entry, strerror(-refcount)); 1096 goto fail; 1097 } 1098 if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { 1099 fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" 1100 PRIx64 " refcount=%d\n", l2_entry, refcount); 1101 res->corruptions++; 1102 } 1103 } 1104 1105 if (flags & CHECK_FRAG_INFO) { 1106 res->bfi.allocated_clusters++; 1107 if (next_contiguous_offset && 1108 offset != next_contiguous_offset) { 1109 res->bfi.fragmented_clusters++; 1110 } 1111 next_contiguous_offset = offset + s->cluster_size; 1112 } 1113 1114 /* Mark cluster as used */ 1115 inc_refcounts(bs, res, refcount_table,refcount_table_size, 1116 offset, s->cluster_size); 1117 1118 /* Correct offsets are cluster aligned */ 1119 if (offset & (s->cluster_size - 1)) { 1120 fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " 1121 "properly aligned; L2 entry corrupted.\n", offset); 1122 res->corruptions++; 1123 } 1124 break; 1125 } 1126 1127 case QCOW2_CLUSTER_UNALLOCATED: 1128 break; 1129 1130 default: 1131 abort(); 1132 } 1133 } 1134 1135 g_free(l2_table); 1136 return 0; 1137 1138 fail: 1139 fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n"); 1140 g_free(l2_table); 1141 return -EIO; 1142 } 1143 1144 /* 1145 * Increases the refcount for the L1 table, its L2 tables and all referenced 1146 * clusters in the given refcount table. While doing so, performs some checks 1147 * on L1 and L2 entries. 1148 * 1149 * Returns the number of errors found by the checks or -errno if an internal 1150 * error occurred. 1151 */ 1152 static int check_refcounts_l1(BlockDriverState *bs, 1153 BdrvCheckResult *res, 1154 uint16_t *refcount_table, 1155 int refcount_table_size, 1156 int64_t l1_table_offset, int l1_size, 1157 int flags) 1158 { 1159 BDRVQcowState *s = bs->opaque; 1160 uint64_t *l1_table, l2_offset, l1_size2; 1161 int i, refcount, ret; 1162 1163 l1_size2 = l1_size * sizeof(uint64_t); 1164 1165 /* Mark L1 table as used */ 1166 inc_refcounts(bs, res, refcount_table, refcount_table_size, 1167 l1_table_offset, l1_size2); 1168 1169 /* Read L1 table entries from disk */ 1170 if (l1_size2 == 0) { 1171 l1_table = NULL; 1172 } else { 1173 l1_table = g_malloc(l1_size2); 1174 if (bdrv_pread(bs->file, l1_table_offset, 1175 l1_table, l1_size2) != l1_size2) 1176 goto fail; 1177 for(i = 0;i < l1_size; i++) 1178 be64_to_cpus(&l1_table[i]); 1179 } 1180 1181 /* Do the actual checks */ 1182 for(i = 0; i < l1_size; i++) { 1183 l2_offset = l1_table[i]; 1184 if (l2_offset) { 1185 /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ 1186 if (flags & CHECK_OFLAG_COPIED) { 1187 refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) 1188 >> s->cluster_bits); 1189 if (refcount < 0) { 1190 fprintf(stderr, "Can't get refcount for l2_offset %" 1191 PRIx64 ": %s\n", l2_offset, strerror(-refcount)); 1192 goto fail; 1193 } 1194 if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { 1195 fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 1196 " refcount=%d\n", l2_offset, refcount); 1197 res->corruptions++; 1198 } 1199 } 1200 1201 /* Mark L2 table as used */ 1202 l2_offset &= L1E_OFFSET_MASK; 1203 inc_refcounts(bs, res, refcount_table, refcount_table_size, 1204 l2_offset, s->cluster_size); 1205 1206 /* L2 tables are cluster aligned */ 1207 if (l2_offset & (s->cluster_size - 1)) { 1208 fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " 1209 "cluster aligned; L1 entry corrupted\n", l2_offset); 1210 res->corruptions++; 1211 } 1212 1213 /* Process and check L2 entries */ 1214 ret = check_refcounts_l2(bs, res, refcount_table, 1215 refcount_table_size, l2_offset, flags); 1216 if (ret < 0) { 1217 goto fail; 1218 } 1219 } 1220 } 1221 g_free(l1_table); 1222 return 0; 1223 1224 fail: 1225 fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); 1226 res->check_errors++; 1227 g_free(l1_table); 1228 return -EIO; 1229 } 1230 1231 /* 1232 * Checks an image for refcount consistency. 1233 * 1234 * Returns 0 if no errors are found, the number of errors in case the image is 1235 * detected as corrupted, and -errno when an internal error occurred. 1236 */ 1237 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 1238 BdrvCheckMode fix) 1239 { 1240 BDRVQcowState *s = bs->opaque; 1241 int64_t size, i, highest_cluster; 1242 int nb_clusters, refcount1, refcount2; 1243 QCowSnapshot *sn; 1244 uint16_t *refcount_table; 1245 int ret; 1246 1247 size = bdrv_getlength(bs->file); 1248 nb_clusters = size_to_clusters(s, size); 1249 refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t)); 1250 1251 res->bfi.total_clusters = 1252 size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); 1253 1254 /* header */ 1255 inc_refcounts(bs, res, refcount_table, nb_clusters, 1256 0, s->cluster_size); 1257 1258 /* current L1 table */ 1259 ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, 1260 s->l1_table_offset, s->l1_size, 1261 CHECK_OFLAG_COPIED | CHECK_FRAG_INFO); 1262 if (ret < 0) { 1263 goto fail; 1264 } 1265 1266 /* snapshots */ 1267 for(i = 0; i < s->nb_snapshots; i++) { 1268 sn = s->snapshots + i; 1269 ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, 1270 sn->l1_table_offset, sn->l1_size, 0); 1271 if (ret < 0) { 1272 goto fail; 1273 } 1274 } 1275 inc_refcounts(bs, res, refcount_table, nb_clusters, 1276 s->snapshots_offset, s->snapshots_size); 1277 1278 /* refcount data */ 1279 inc_refcounts(bs, res, refcount_table, nb_clusters, 1280 s->refcount_table_offset, 1281 s->refcount_table_size * sizeof(uint64_t)); 1282 1283 for(i = 0; i < s->refcount_table_size; i++) { 1284 uint64_t offset, cluster; 1285 offset = s->refcount_table[i]; 1286 cluster = offset >> s->cluster_bits; 1287 1288 /* Refcount blocks are cluster aligned */ 1289 if (offset & (s->cluster_size - 1)) { 1290 fprintf(stderr, "ERROR refcount block %" PRId64 " is not " 1291 "cluster aligned; refcount table entry corrupted\n", i); 1292 res->corruptions++; 1293 continue; 1294 } 1295 1296 if (cluster >= nb_clusters) { 1297 fprintf(stderr, "ERROR refcount block %" PRId64 1298 " is outside image\n", i); 1299 res->corruptions++; 1300 continue; 1301 } 1302 1303 if (offset != 0) { 1304 inc_refcounts(bs, res, refcount_table, nb_clusters, 1305 offset, s->cluster_size); 1306 if (refcount_table[cluster] != 1) { 1307 fprintf(stderr, "ERROR refcount block %" PRId64 1308 " refcount=%d\n", 1309 i, refcount_table[cluster]); 1310 res->corruptions++; 1311 } 1312 } 1313 } 1314 1315 /* compare ref counts */ 1316 for (i = 0, highest_cluster = 0; i < nb_clusters; i++) { 1317 refcount1 = get_refcount(bs, i); 1318 if (refcount1 < 0) { 1319 fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", 1320 i, strerror(-refcount1)); 1321 res->check_errors++; 1322 continue; 1323 } 1324 1325 refcount2 = refcount_table[i]; 1326 1327 if (refcount1 > 0 || refcount2 > 0) { 1328 highest_cluster = i; 1329 } 1330 1331 if (refcount1 != refcount2) { 1332 1333 /* Check if we're allowed to fix the mismatch */ 1334 int *num_fixed = NULL; 1335 if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) { 1336 num_fixed = &res->leaks_fixed; 1337 } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) { 1338 num_fixed = &res->corruptions_fixed; 1339 } 1340 1341 fprintf(stderr, "%s cluster %" PRId64 " refcount=%d reference=%d\n", 1342 num_fixed != NULL ? "Repairing" : 1343 refcount1 < refcount2 ? "ERROR" : 1344 "Leaked", 1345 i, refcount1, refcount2); 1346 1347 if (num_fixed) { 1348 ret = update_refcount(bs, i << s->cluster_bits, 1, 1349 refcount2 - refcount1, 1350 QCOW2_DISCARD_ALWAYS); 1351 if (ret >= 0) { 1352 (*num_fixed)++; 1353 continue; 1354 } 1355 } 1356 1357 /* And if we couldn't, print an error */ 1358 if (refcount1 < refcount2) { 1359 res->corruptions++; 1360 } else { 1361 res->leaks++; 1362 } 1363 } 1364 } 1365 1366 res->image_end_offset = (highest_cluster + 1) * s->cluster_size; 1367 ret = 0; 1368 1369 fail: 1370 g_free(refcount_table); 1371 1372 return ret; 1373 } 1374 1375