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/osdep.h" 26 #include "block/block_int.h" 27 #include "sysemu/block-backend.h" 28 #include "qemu/module.h" 29 #include <zlib.h> 30 #include "block/qcow2.h" 31 #include "qemu/error-report.h" 32 #include "qapi/error.h" 33 #include "qapi/qapi-events-block-core.h" 34 #include "qapi/qmp/qdict.h" 35 #include "qapi/qmp/qstring.h" 36 #include "trace.h" 37 #include "qemu/option_int.h" 38 #include "qemu/cutils.h" 39 #include "qemu/bswap.h" 40 #include "qapi/opts-visitor.h" 41 #include "block/crypto.h" 42 43 /* 44 Differences with QCOW: 45 46 - Support for multiple incremental snapshots. 47 - Memory management by reference counts. 48 - Clusters which have a reference count of one have the bit 49 QCOW_OFLAG_COPIED to optimize write performance. 50 - Size of compressed clusters is stored in sectors to reduce bit usage 51 in the cluster offsets. 52 - Support for storing additional data (such as the VM state) in the 53 snapshots. 54 - If a backing store is used, the cluster size is not constrained 55 (could be backported to QCOW). 56 - L2 tables have always a size of one cluster. 57 */ 58 59 60 typedef struct { 61 uint32_t magic; 62 uint32_t len; 63 } QEMU_PACKED QCowExtension; 64 65 #define QCOW2_EXT_MAGIC_END 0 66 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 67 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 68 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 69 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 70 71 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 72 { 73 const QCowHeader *cow_header = (const void *)buf; 74 75 if (buf_size >= sizeof(QCowHeader) && 76 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 77 be32_to_cpu(cow_header->version) >= 2) 78 return 100; 79 else 80 return 0; 81 } 82 83 84 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 85 uint8_t *buf, size_t buflen, 86 void *opaque, Error **errp) 87 { 88 BlockDriverState *bs = opaque; 89 BDRVQcow2State *s = bs->opaque; 90 ssize_t ret; 91 92 if ((offset + buflen) > s->crypto_header.length) { 93 error_setg(errp, "Request for data outside of extension header"); 94 return -1; 95 } 96 97 ret = bdrv_pread(bs->file, 98 s->crypto_header.offset + offset, buf, buflen); 99 if (ret < 0) { 100 error_setg_errno(errp, -ret, "Could not read encryption header"); 101 return -1; 102 } 103 return ret; 104 } 105 106 107 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 108 void *opaque, Error **errp) 109 { 110 BlockDriverState *bs = opaque; 111 BDRVQcow2State *s = bs->opaque; 112 int64_t ret; 113 int64_t clusterlen; 114 115 ret = qcow2_alloc_clusters(bs, headerlen); 116 if (ret < 0) { 117 error_setg_errno(errp, -ret, 118 "Cannot allocate cluster for LUKS header size %zu", 119 headerlen); 120 return -1; 121 } 122 123 s->crypto_header.length = headerlen; 124 s->crypto_header.offset = ret; 125 126 /* Zero fill remaining space in cluster so it has predictable 127 * content in case of future spec changes */ 128 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 129 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen) == 0); 130 ret = bdrv_pwrite_zeroes(bs->file, 131 ret + headerlen, 132 clusterlen - headerlen, 0); 133 if (ret < 0) { 134 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 135 return -1; 136 } 137 138 return ret; 139 } 140 141 142 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 143 const uint8_t *buf, size_t buflen, 144 void *opaque, Error **errp) 145 { 146 BlockDriverState *bs = opaque; 147 BDRVQcow2State *s = bs->opaque; 148 ssize_t ret; 149 150 if ((offset + buflen) > s->crypto_header.length) { 151 error_setg(errp, "Request for data outside of extension header"); 152 return -1; 153 } 154 155 ret = bdrv_pwrite(bs->file, 156 s->crypto_header.offset + offset, buf, buflen); 157 if (ret < 0) { 158 error_setg_errno(errp, -ret, "Could not read encryption header"); 159 return -1; 160 } 161 return ret; 162 } 163 164 165 /* 166 * read qcow2 extension and fill bs 167 * start reading from start_offset 168 * finish reading upon magic of value 0 or when end_offset reached 169 * unknown magic is skipped (future extension this version knows nothing about) 170 * return 0 upon success, non-0 otherwise 171 */ 172 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 173 uint64_t end_offset, void **p_feature_table, 174 int flags, bool *need_update_header, 175 Error **errp) 176 { 177 BDRVQcow2State *s = bs->opaque; 178 QCowExtension ext; 179 uint64_t offset; 180 int ret; 181 Qcow2BitmapHeaderExt bitmaps_ext; 182 183 if (need_update_header != NULL) { 184 *need_update_header = false; 185 } 186 187 #ifdef DEBUG_EXT 188 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 189 #endif 190 offset = start_offset; 191 while (offset < end_offset) { 192 193 #ifdef DEBUG_EXT 194 /* Sanity check */ 195 if (offset > s->cluster_size) 196 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 197 198 printf("attempting to read extended header in offset %lu\n", offset); 199 #endif 200 201 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 202 if (ret < 0) { 203 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 204 "pread fail from offset %" PRIu64, offset); 205 return 1; 206 } 207 be32_to_cpus(&ext.magic); 208 be32_to_cpus(&ext.len); 209 offset += sizeof(ext); 210 #ifdef DEBUG_EXT 211 printf("ext.magic = 0x%x\n", ext.magic); 212 #endif 213 if (offset > end_offset || ext.len > end_offset - offset) { 214 error_setg(errp, "Header extension too large"); 215 return -EINVAL; 216 } 217 218 switch (ext.magic) { 219 case QCOW2_EXT_MAGIC_END: 220 return 0; 221 222 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 223 if (ext.len >= sizeof(bs->backing_format)) { 224 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 225 " too large (>=%zu)", ext.len, 226 sizeof(bs->backing_format)); 227 return 2; 228 } 229 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 230 if (ret < 0) { 231 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 232 "Could not read format name"); 233 return 3; 234 } 235 bs->backing_format[ext.len] = '\0'; 236 s->image_backing_format = g_strdup(bs->backing_format); 237 #ifdef DEBUG_EXT 238 printf("Qcow2: Got format extension %s\n", bs->backing_format); 239 #endif 240 break; 241 242 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 243 if (p_feature_table != NULL) { 244 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 245 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 246 if (ret < 0) { 247 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 248 "Could not read table"); 249 return ret; 250 } 251 252 *p_feature_table = feature_table; 253 } 254 break; 255 256 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 257 unsigned int cflags = 0; 258 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 259 error_setg(errp, "CRYPTO header extension only " 260 "expected with LUKS encryption method"); 261 return -EINVAL; 262 } 263 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 264 error_setg(errp, "CRYPTO header extension size %u, " 265 "but expected size %zu", ext.len, 266 sizeof(Qcow2CryptoHeaderExtension)); 267 return -EINVAL; 268 } 269 270 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 271 if (ret < 0) { 272 error_setg_errno(errp, -ret, 273 "Unable to read CRYPTO header extension"); 274 return ret; 275 } 276 be64_to_cpus(&s->crypto_header.offset); 277 be64_to_cpus(&s->crypto_header.length); 278 279 if ((s->crypto_header.offset % s->cluster_size) != 0) { 280 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 281 "not a multiple of cluster size '%u'", 282 s->crypto_header.offset, s->cluster_size); 283 return -EINVAL; 284 } 285 286 if (flags & BDRV_O_NO_IO) { 287 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 288 } 289 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 290 qcow2_crypto_hdr_read_func, 291 bs, cflags, errp); 292 if (!s->crypto) { 293 return -EINVAL; 294 } 295 } break; 296 297 case QCOW2_EXT_MAGIC_BITMAPS: 298 if (ext.len != sizeof(bitmaps_ext)) { 299 error_setg_errno(errp, -ret, "bitmaps_ext: " 300 "Invalid extension length"); 301 return -EINVAL; 302 } 303 304 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 305 if (s->qcow_version < 3) { 306 /* Let's be a bit more specific */ 307 warn_report("This qcow2 v2 image contains bitmaps, but " 308 "they may have been modified by a program " 309 "without persistent bitmap support; so now " 310 "they must all be considered inconsistent"); 311 } else { 312 warn_report("a program lacking bitmap support " 313 "modified this file, so all bitmaps are now " 314 "considered inconsistent"); 315 } 316 error_printf("Some clusters may be leaked, " 317 "run 'qemu-img check -r' on the image " 318 "file to fix."); 319 if (need_update_header != NULL) { 320 /* Updating is needed to drop invalid bitmap extension. */ 321 *need_update_header = true; 322 } 323 break; 324 } 325 326 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 327 if (ret < 0) { 328 error_setg_errno(errp, -ret, "bitmaps_ext: " 329 "Could not read ext header"); 330 return ret; 331 } 332 333 if (bitmaps_ext.reserved32 != 0) { 334 error_setg_errno(errp, -ret, "bitmaps_ext: " 335 "Reserved field is not zero"); 336 return -EINVAL; 337 } 338 339 be32_to_cpus(&bitmaps_ext.nb_bitmaps); 340 be64_to_cpus(&bitmaps_ext.bitmap_directory_size); 341 be64_to_cpus(&bitmaps_ext.bitmap_directory_offset); 342 343 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 344 error_setg(errp, 345 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 346 "exceeding the QEMU supported maximum of %d", 347 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 348 return -EINVAL; 349 } 350 351 if (bitmaps_ext.nb_bitmaps == 0) { 352 error_setg(errp, "found bitmaps extension with zero bitmaps"); 353 return -EINVAL; 354 } 355 356 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 357 error_setg(errp, "bitmaps_ext: " 358 "invalid bitmap directory offset"); 359 return -EINVAL; 360 } 361 362 if (bitmaps_ext.bitmap_directory_size > 363 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 364 error_setg(errp, "bitmaps_ext: " 365 "bitmap directory size (%" PRIu64 ") exceeds " 366 "the maximum supported size (%d)", 367 bitmaps_ext.bitmap_directory_size, 368 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 369 return -EINVAL; 370 } 371 372 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 373 s->bitmap_directory_offset = 374 bitmaps_ext.bitmap_directory_offset; 375 s->bitmap_directory_size = 376 bitmaps_ext.bitmap_directory_size; 377 378 #ifdef DEBUG_EXT 379 printf("Qcow2: Got bitmaps extension: " 380 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 381 s->bitmap_directory_offset, s->nb_bitmaps); 382 #endif 383 break; 384 385 default: 386 /* unknown magic - save it in case we need to rewrite the header */ 387 /* If you add a new feature, make sure to also update the fast 388 * path of qcow2_make_empty() to deal with it. */ 389 { 390 Qcow2UnknownHeaderExtension *uext; 391 392 uext = g_malloc0(sizeof(*uext) + ext.len); 393 uext->magic = ext.magic; 394 uext->len = ext.len; 395 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 396 397 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 398 if (ret < 0) { 399 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 400 "Could not read data"); 401 return ret; 402 } 403 } 404 break; 405 } 406 407 offset += ((ext.len + 7) & ~7); 408 } 409 410 return 0; 411 } 412 413 static void cleanup_unknown_header_ext(BlockDriverState *bs) 414 { 415 BDRVQcow2State *s = bs->opaque; 416 Qcow2UnknownHeaderExtension *uext, *next; 417 418 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 419 QLIST_REMOVE(uext, next); 420 g_free(uext); 421 } 422 } 423 424 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 425 uint64_t mask) 426 { 427 char *features = g_strdup(""); 428 char *old; 429 430 while (table && table->name[0] != '\0') { 431 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 432 if (mask & (1ULL << table->bit)) { 433 old = features; 434 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 435 table->name); 436 g_free(old); 437 mask &= ~(1ULL << table->bit); 438 } 439 } 440 table++; 441 } 442 443 if (mask) { 444 old = features; 445 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 446 old, *old ? ", " : "", mask); 447 g_free(old); 448 } 449 450 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 451 g_free(features); 452 } 453 454 /* 455 * Sets the dirty bit and flushes afterwards if necessary. 456 * 457 * The incompatible_features bit is only set if the image file header was 458 * updated successfully. Therefore it is not required to check the return 459 * value of this function. 460 */ 461 int qcow2_mark_dirty(BlockDriverState *bs) 462 { 463 BDRVQcow2State *s = bs->opaque; 464 uint64_t val; 465 int ret; 466 467 assert(s->qcow_version >= 3); 468 469 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 470 return 0; /* already dirty */ 471 } 472 473 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 474 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 475 &val, sizeof(val)); 476 if (ret < 0) { 477 return ret; 478 } 479 ret = bdrv_flush(bs->file->bs); 480 if (ret < 0) { 481 return ret; 482 } 483 484 /* Only treat image as dirty if the header was updated successfully */ 485 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 486 return 0; 487 } 488 489 /* 490 * Clears the dirty bit and flushes before if necessary. Only call this 491 * function when there are no pending requests, it does not guard against 492 * concurrent requests dirtying the image. 493 */ 494 static int qcow2_mark_clean(BlockDriverState *bs) 495 { 496 BDRVQcow2State *s = bs->opaque; 497 498 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 499 int ret; 500 501 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 502 503 ret = bdrv_flush(bs); 504 if (ret < 0) { 505 return ret; 506 } 507 508 return qcow2_update_header(bs); 509 } 510 return 0; 511 } 512 513 /* 514 * Marks the image as corrupt. 515 */ 516 int qcow2_mark_corrupt(BlockDriverState *bs) 517 { 518 BDRVQcow2State *s = bs->opaque; 519 520 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 521 return qcow2_update_header(bs); 522 } 523 524 /* 525 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 526 * before if necessary. 527 */ 528 int qcow2_mark_consistent(BlockDriverState *bs) 529 { 530 BDRVQcow2State *s = bs->opaque; 531 532 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 533 int ret = bdrv_flush(bs); 534 if (ret < 0) { 535 return ret; 536 } 537 538 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 539 return qcow2_update_header(bs); 540 } 541 return 0; 542 } 543 544 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 545 BdrvCheckMode fix) 546 { 547 int ret = qcow2_check_refcounts(bs, result, fix); 548 if (ret < 0) { 549 return ret; 550 } 551 552 if (fix && result->check_errors == 0 && result->corruptions == 0) { 553 ret = qcow2_mark_clean(bs); 554 if (ret < 0) { 555 return ret; 556 } 557 return qcow2_mark_consistent(bs); 558 } 559 return ret; 560 } 561 562 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 563 uint64_t entries, size_t entry_len) 564 { 565 BDRVQcow2State *s = bs->opaque; 566 uint64_t size; 567 568 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 569 * because values will be passed to qemu functions taking int64_t. */ 570 if (entries > INT64_MAX / entry_len) { 571 return -EINVAL; 572 } 573 574 size = entries * entry_len; 575 576 if (INT64_MAX - size < offset) { 577 return -EINVAL; 578 } 579 580 /* Tables must be cluster aligned */ 581 if (offset_into_cluster(s, offset) != 0) { 582 return -EINVAL; 583 } 584 585 return 0; 586 } 587 588 static QemuOptsList qcow2_runtime_opts = { 589 .name = "qcow2", 590 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 591 .desc = { 592 { 593 .name = QCOW2_OPT_LAZY_REFCOUNTS, 594 .type = QEMU_OPT_BOOL, 595 .help = "Postpone refcount updates", 596 }, 597 { 598 .name = QCOW2_OPT_DISCARD_REQUEST, 599 .type = QEMU_OPT_BOOL, 600 .help = "Pass guest discard requests to the layer below", 601 }, 602 { 603 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 604 .type = QEMU_OPT_BOOL, 605 .help = "Generate discard requests when snapshot related space " 606 "is freed", 607 }, 608 { 609 .name = QCOW2_OPT_DISCARD_OTHER, 610 .type = QEMU_OPT_BOOL, 611 .help = "Generate discard requests when other clusters are freed", 612 }, 613 { 614 .name = QCOW2_OPT_OVERLAP, 615 .type = QEMU_OPT_STRING, 616 .help = "Selects which overlap checks to perform from a range of " 617 "templates (none, constant, cached, all)", 618 }, 619 { 620 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 621 .type = QEMU_OPT_STRING, 622 .help = "Selects which overlap checks to perform from a range of " 623 "templates (none, constant, cached, all)", 624 }, 625 { 626 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 627 .type = QEMU_OPT_BOOL, 628 .help = "Check for unintended writes into the main qcow2 header", 629 }, 630 { 631 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 632 .type = QEMU_OPT_BOOL, 633 .help = "Check for unintended writes into the active L1 table", 634 }, 635 { 636 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 637 .type = QEMU_OPT_BOOL, 638 .help = "Check for unintended writes into an active L2 table", 639 }, 640 { 641 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 642 .type = QEMU_OPT_BOOL, 643 .help = "Check for unintended writes into the refcount table", 644 }, 645 { 646 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 647 .type = QEMU_OPT_BOOL, 648 .help = "Check for unintended writes into a refcount block", 649 }, 650 { 651 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 652 .type = QEMU_OPT_BOOL, 653 .help = "Check for unintended writes into the snapshot table", 654 }, 655 { 656 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 657 .type = QEMU_OPT_BOOL, 658 .help = "Check for unintended writes into an inactive L1 table", 659 }, 660 { 661 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 662 .type = QEMU_OPT_BOOL, 663 .help = "Check for unintended writes into an inactive L2 table", 664 }, 665 { 666 .name = QCOW2_OPT_CACHE_SIZE, 667 .type = QEMU_OPT_SIZE, 668 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 669 "cache size", 670 }, 671 { 672 .name = QCOW2_OPT_L2_CACHE_SIZE, 673 .type = QEMU_OPT_SIZE, 674 .help = "Maximum L2 table cache size", 675 }, 676 { 677 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 678 .type = QEMU_OPT_SIZE, 679 .help = "Size of each entry in the L2 cache", 680 }, 681 { 682 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 683 .type = QEMU_OPT_SIZE, 684 .help = "Maximum refcount block cache size", 685 }, 686 { 687 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 688 .type = QEMU_OPT_NUMBER, 689 .help = "Clean unused cache entries after this time (in seconds)", 690 }, 691 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 692 "ID of secret providing qcow2 AES key or LUKS passphrase"), 693 { /* end of list */ } 694 }, 695 }; 696 697 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 698 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 699 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 700 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 701 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 702 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 703 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 704 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 705 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 706 }; 707 708 static void cache_clean_timer_cb(void *opaque) 709 { 710 BlockDriverState *bs = opaque; 711 BDRVQcow2State *s = bs->opaque; 712 qcow2_cache_clean_unused(s->l2_table_cache); 713 qcow2_cache_clean_unused(s->refcount_block_cache); 714 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 715 (int64_t) s->cache_clean_interval * 1000); 716 } 717 718 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 719 { 720 BDRVQcow2State *s = bs->opaque; 721 if (s->cache_clean_interval > 0) { 722 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 723 SCALE_MS, cache_clean_timer_cb, 724 bs); 725 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 726 (int64_t) s->cache_clean_interval * 1000); 727 } 728 } 729 730 static void cache_clean_timer_del(BlockDriverState *bs) 731 { 732 BDRVQcow2State *s = bs->opaque; 733 if (s->cache_clean_timer) { 734 timer_del(s->cache_clean_timer); 735 timer_free(s->cache_clean_timer); 736 s->cache_clean_timer = NULL; 737 } 738 } 739 740 static void qcow2_detach_aio_context(BlockDriverState *bs) 741 { 742 cache_clean_timer_del(bs); 743 } 744 745 static void qcow2_attach_aio_context(BlockDriverState *bs, 746 AioContext *new_context) 747 { 748 cache_clean_timer_init(bs, new_context); 749 } 750 751 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 752 uint64_t *l2_cache_size, 753 uint64_t *l2_cache_entry_size, 754 uint64_t *refcount_cache_size, Error **errp) 755 { 756 BDRVQcow2State *s = bs->opaque; 757 uint64_t combined_cache_size; 758 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 759 760 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 761 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 762 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 763 764 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 765 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 766 *refcount_cache_size = qemu_opt_get_size(opts, 767 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 768 769 *l2_cache_entry_size = qemu_opt_get_size( 770 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 771 772 if (combined_cache_size_set) { 773 if (l2_cache_size_set && refcount_cache_size_set) { 774 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 775 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 776 "the same time"); 777 return; 778 } else if (*l2_cache_size > combined_cache_size) { 779 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 780 QCOW2_OPT_CACHE_SIZE); 781 return; 782 } else if (*refcount_cache_size > combined_cache_size) { 783 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 784 QCOW2_OPT_CACHE_SIZE); 785 return; 786 } 787 788 if (l2_cache_size_set) { 789 *refcount_cache_size = combined_cache_size - *l2_cache_size; 790 } else if (refcount_cache_size_set) { 791 *l2_cache_size = combined_cache_size - *refcount_cache_size; 792 } else { 793 *refcount_cache_size = combined_cache_size 794 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 795 *l2_cache_size = combined_cache_size - *refcount_cache_size; 796 } 797 } else { 798 if (!l2_cache_size_set && !refcount_cache_size_set) { 799 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 800 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 801 * s->cluster_size); 802 *refcount_cache_size = *l2_cache_size 803 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 804 } else if (!l2_cache_size_set) { 805 *l2_cache_size = *refcount_cache_size 806 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 807 } else if (!refcount_cache_size_set) { 808 *refcount_cache_size = *l2_cache_size 809 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 810 } 811 } 812 813 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 814 *l2_cache_entry_size > s->cluster_size || 815 !is_power_of_2(*l2_cache_entry_size)) { 816 error_setg(errp, "L2 cache entry size must be a power of two " 817 "between %d and the cluster size (%d)", 818 1 << MIN_CLUSTER_BITS, s->cluster_size); 819 return; 820 } 821 } 822 823 typedef struct Qcow2ReopenState { 824 Qcow2Cache *l2_table_cache; 825 Qcow2Cache *refcount_block_cache; 826 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 827 bool use_lazy_refcounts; 828 int overlap_check; 829 bool discard_passthrough[QCOW2_DISCARD_MAX]; 830 uint64_t cache_clean_interval; 831 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 832 } Qcow2ReopenState; 833 834 static int qcow2_update_options_prepare(BlockDriverState *bs, 835 Qcow2ReopenState *r, 836 QDict *options, int flags, 837 Error **errp) 838 { 839 BDRVQcow2State *s = bs->opaque; 840 QemuOpts *opts = NULL; 841 const char *opt_overlap_check, *opt_overlap_check_template; 842 int overlap_check_template = 0; 843 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 844 int i; 845 const char *encryptfmt; 846 QDict *encryptopts = NULL; 847 Error *local_err = NULL; 848 int ret; 849 850 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 851 encryptfmt = qdict_get_try_str(encryptopts, "format"); 852 853 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 854 qemu_opts_absorb_qdict(opts, options, &local_err); 855 if (local_err) { 856 error_propagate(errp, local_err); 857 ret = -EINVAL; 858 goto fail; 859 } 860 861 /* get L2 table/refcount block cache size from command line options */ 862 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 863 &refcount_cache_size, &local_err); 864 if (local_err) { 865 error_propagate(errp, local_err); 866 ret = -EINVAL; 867 goto fail; 868 } 869 870 l2_cache_size /= l2_cache_entry_size; 871 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 872 l2_cache_size = MIN_L2_CACHE_SIZE; 873 } 874 if (l2_cache_size > INT_MAX) { 875 error_setg(errp, "L2 cache size too big"); 876 ret = -EINVAL; 877 goto fail; 878 } 879 880 refcount_cache_size /= s->cluster_size; 881 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 882 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 883 } 884 if (refcount_cache_size > INT_MAX) { 885 error_setg(errp, "Refcount cache size too big"); 886 ret = -EINVAL; 887 goto fail; 888 } 889 890 /* alloc new L2 table/refcount block cache, flush old one */ 891 if (s->l2_table_cache) { 892 ret = qcow2_cache_flush(bs, s->l2_table_cache); 893 if (ret) { 894 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 895 goto fail; 896 } 897 } 898 899 if (s->refcount_block_cache) { 900 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 901 if (ret) { 902 error_setg_errno(errp, -ret, 903 "Failed to flush the refcount block cache"); 904 goto fail; 905 } 906 } 907 908 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 909 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 910 l2_cache_entry_size); 911 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 912 s->cluster_size); 913 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 914 error_setg(errp, "Could not allocate metadata caches"); 915 ret = -ENOMEM; 916 goto fail; 917 } 918 919 /* New interval for cache cleanup timer */ 920 r->cache_clean_interval = 921 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 922 s->cache_clean_interval); 923 #ifndef CONFIG_LINUX 924 if (r->cache_clean_interval != 0) { 925 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 926 " not supported on this host"); 927 ret = -EINVAL; 928 goto fail; 929 } 930 #endif 931 if (r->cache_clean_interval > UINT_MAX) { 932 error_setg(errp, "Cache clean interval too big"); 933 ret = -EINVAL; 934 goto fail; 935 } 936 937 /* lazy-refcounts; flush if going from enabled to disabled */ 938 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 939 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 940 if (r->use_lazy_refcounts && s->qcow_version < 3) { 941 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 942 "qemu 1.1 compatibility level"); 943 ret = -EINVAL; 944 goto fail; 945 } 946 947 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 948 ret = qcow2_mark_clean(bs); 949 if (ret < 0) { 950 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 951 goto fail; 952 } 953 } 954 955 /* Overlap check options */ 956 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 957 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 958 if (opt_overlap_check_template && opt_overlap_check && 959 strcmp(opt_overlap_check_template, opt_overlap_check)) 960 { 961 error_setg(errp, "Conflicting values for qcow2 options '" 962 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 963 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 964 ret = -EINVAL; 965 goto fail; 966 } 967 if (!opt_overlap_check) { 968 opt_overlap_check = opt_overlap_check_template ?: "cached"; 969 } 970 971 if (!strcmp(opt_overlap_check, "none")) { 972 overlap_check_template = 0; 973 } else if (!strcmp(opt_overlap_check, "constant")) { 974 overlap_check_template = QCOW2_OL_CONSTANT; 975 } else if (!strcmp(opt_overlap_check, "cached")) { 976 overlap_check_template = QCOW2_OL_CACHED; 977 } else if (!strcmp(opt_overlap_check, "all")) { 978 overlap_check_template = QCOW2_OL_ALL; 979 } else { 980 error_setg(errp, "Unsupported value '%s' for qcow2 option " 981 "'overlap-check'. Allowed are any of the following: " 982 "none, constant, cached, all", opt_overlap_check); 983 ret = -EINVAL; 984 goto fail; 985 } 986 987 r->overlap_check = 0; 988 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 989 /* overlap-check defines a template bitmask, but every flag may be 990 * overwritten through the associated boolean option */ 991 r->overlap_check |= 992 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 993 overlap_check_template & (1 << i)) << i; 994 } 995 996 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 997 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 998 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 999 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1000 flags & BDRV_O_UNMAP); 1001 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1002 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1003 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1004 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1005 1006 switch (s->crypt_method_header) { 1007 case QCOW_CRYPT_NONE: 1008 if (encryptfmt) { 1009 error_setg(errp, "No encryption in image header, but options " 1010 "specified format '%s'", encryptfmt); 1011 ret = -EINVAL; 1012 goto fail; 1013 } 1014 break; 1015 1016 case QCOW_CRYPT_AES: 1017 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1018 error_setg(errp, 1019 "Header reported 'aes' encryption format but " 1020 "options specify '%s'", encryptfmt); 1021 ret = -EINVAL; 1022 goto fail; 1023 } 1024 qdict_del(encryptopts, "format"); 1025 r->crypto_opts = block_crypto_open_opts_init( 1026 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 1027 break; 1028 1029 case QCOW_CRYPT_LUKS: 1030 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1031 error_setg(errp, 1032 "Header reported 'luks' encryption format but " 1033 "options specify '%s'", encryptfmt); 1034 ret = -EINVAL; 1035 goto fail; 1036 } 1037 qdict_del(encryptopts, "format"); 1038 r->crypto_opts = block_crypto_open_opts_init( 1039 Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); 1040 break; 1041 1042 default: 1043 error_setg(errp, "Unsupported encryption method %d", 1044 s->crypt_method_header); 1045 break; 1046 } 1047 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1048 ret = -EINVAL; 1049 goto fail; 1050 } 1051 1052 ret = 0; 1053 fail: 1054 QDECREF(encryptopts); 1055 qemu_opts_del(opts); 1056 opts = NULL; 1057 return ret; 1058 } 1059 1060 static void qcow2_update_options_commit(BlockDriverState *bs, 1061 Qcow2ReopenState *r) 1062 { 1063 BDRVQcow2State *s = bs->opaque; 1064 int i; 1065 1066 if (s->l2_table_cache) { 1067 qcow2_cache_destroy(s->l2_table_cache); 1068 } 1069 if (s->refcount_block_cache) { 1070 qcow2_cache_destroy(s->refcount_block_cache); 1071 } 1072 s->l2_table_cache = r->l2_table_cache; 1073 s->refcount_block_cache = r->refcount_block_cache; 1074 s->l2_slice_size = r->l2_slice_size; 1075 1076 s->overlap_check = r->overlap_check; 1077 s->use_lazy_refcounts = r->use_lazy_refcounts; 1078 1079 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1080 s->discard_passthrough[i] = r->discard_passthrough[i]; 1081 } 1082 1083 if (s->cache_clean_interval != r->cache_clean_interval) { 1084 cache_clean_timer_del(bs); 1085 s->cache_clean_interval = r->cache_clean_interval; 1086 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1087 } 1088 1089 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1090 s->crypto_opts = r->crypto_opts; 1091 } 1092 1093 static void qcow2_update_options_abort(BlockDriverState *bs, 1094 Qcow2ReopenState *r) 1095 { 1096 if (r->l2_table_cache) { 1097 qcow2_cache_destroy(r->l2_table_cache); 1098 } 1099 if (r->refcount_block_cache) { 1100 qcow2_cache_destroy(r->refcount_block_cache); 1101 } 1102 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1103 } 1104 1105 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1106 int flags, Error **errp) 1107 { 1108 Qcow2ReopenState r = {}; 1109 int ret; 1110 1111 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1112 if (ret >= 0) { 1113 qcow2_update_options_commit(bs, &r); 1114 } else { 1115 qcow2_update_options_abort(bs, &r); 1116 } 1117 1118 return ret; 1119 } 1120 1121 static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, 1122 Error **errp) 1123 { 1124 BDRVQcow2State *s = bs->opaque; 1125 unsigned int len, i; 1126 int ret = 0; 1127 QCowHeader header; 1128 Error *local_err = NULL; 1129 uint64_t ext_end; 1130 uint64_t l1_vm_state_index; 1131 bool update_header = false; 1132 1133 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1134 if (ret < 0) { 1135 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1136 goto fail; 1137 } 1138 be32_to_cpus(&header.magic); 1139 be32_to_cpus(&header.version); 1140 be64_to_cpus(&header.backing_file_offset); 1141 be32_to_cpus(&header.backing_file_size); 1142 be64_to_cpus(&header.size); 1143 be32_to_cpus(&header.cluster_bits); 1144 be32_to_cpus(&header.crypt_method); 1145 be64_to_cpus(&header.l1_table_offset); 1146 be32_to_cpus(&header.l1_size); 1147 be64_to_cpus(&header.refcount_table_offset); 1148 be32_to_cpus(&header.refcount_table_clusters); 1149 be64_to_cpus(&header.snapshots_offset); 1150 be32_to_cpus(&header.nb_snapshots); 1151 1152 if (header.magic != QCOW_MAGIC) { 1153 error_setg(errp, "Image is not in qcow2 format"); 1154 ret = -EINVAL; 1155 goto fail; 1156 } 1157 if (header.version < 2 || header.version > 3) { 1158 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1159 ret = -ENOTSUP; 1160 goto fail; 1161 } 1162 1163 s->qcow_version = header.version; 1164 1165 /* Initialise cluster size */ 1166 if (header.cluster_bits < MIN_CLUSTER_BITS || 1167 header.cluster_bits > MAX_CLUSTER_BITS) { 1168 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1169 header.cluster_bits); 1170 ret = -EINVAL; 1171 goto fail; 1172 } 1173 1174 s->cluster_bits = header.cluster_bits; 1175 s->cluster_size = 1 << s->cluster_bits; 1176 s->cluster_sectors = 1 << (s->cluster_bits - BDRV_SECTOR_BITS); 1177 1178 /* Initialise version 3 header fields */ 1179 if (header.version == 2) { 1180 header.incompatible_features = 0; 1181 header.compatible_features = 0; 1182 header.autoclear_features = 0; 1183 header.refcount_order = 4; 1184 header.header_length = 72; 1185 } else { 1186 be64_to_cpus(&header.incompatible_features); 1187 be64_to_cpus(&header.compatible_features); 1188 be64_to_cpus(&header.autoclear_features); 1189 be32_to_cpus(&header.refcount_order); 1190 be32_to_cpus(&header.header_length); 1191 1192 if (header.header_length < 104) { 1193 error_setg(errp, "qcow2 header too short"); 1194 ret = -EINVAL; 1195 goto fail; 1196 } 1197 } 1198 1199 if (header.header_length > s->cluster_size) { 1200 error_setg(errp, "qcow2 header exceeds cluster size"); 1201 ret = -EINVAL; 1202 goto fail; 1203 } 1204 1205 if (header.header_length > sizeof(header)) { 1206 s->unknown_header_fields_size = header.header_length - sizeof(header); 1207 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1208 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1209 s->unknown_header_fields_size); 1210 if (ret < 0) { 1211 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1212 "fields"); 1213 goto fail; 1214 } 1215 } 1216 1217 if (header.backing_file_offset > s->cluster_size) { 1218 error_setg(errp, "Invalid backing file offset"); 1219 ret = -EINVAL; 1220 goto fail; 1221 } 1222 1223 if (header.backing_file_offset) { 1224 ext_end = header.backing_file_offset; 1225 } else { 1226 ext_end = 1 << header.cluster_bits; 1227 } 1228 1229 /* Handle feature bits */ 1230 s->incompatible_features = header.incompatible_features; 1231 s->compatible_features = header.compatible_features; 1232 s->autoclear_features = header.autoclear_features; 1233 1234 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1235 void *feature_table = NULL; 1236 qcow2_read_extensions(bs, header.header_length, ext_end, 1237 &feature_table, flags, NULL, NULL); 1238 report_unsupported_feature(errp, feature_table, 1239 s->incompatible_features & 1240 ~QCOW2_INCOMPAT_MASK); 1241 ret = -ENOTSUP; 1242 g_free(feature_table); 1243 goto fail; 1244 } 1245 1246 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1247 /* Corrupt images may not be written to unless they are being repaired 1248 */ 1249 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1250 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1251 "read/write"); 1252 ret = -EACCES; 1253 goto fail; 1254 } 1255 } 1256 1257 /* Check support for various header values */ 1258 if (header.refcount_order > 6) { 1259 error_setg(errp, "Reference count entry width too large; may not " 1260 "exceed 64 bits"); 1261 ret = -EINVAL; 1262 goto fail; 1263 } 1264 s->refcount_order = header.refcount_order; 1265 s->refcount_bits = 1 << s->refcount_order; 1266 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1267 s->refcount_max += s->refcount_max - 1; 1268 1269 s->crypt_method_header = header.crypt_method; 1270 if (s->crypt_method_header) { 1271 if (bdrv_uses_whitelist() && 1272 s->crypt_method_header == QCOW_CRYPT_AES) { 1273 error_setg(errp, 1274 "Use of AES-CBC encrypted qcow2 images is no longer " 1275 "supported in system emulators"); 1276 error_append_hint(errp, 1277 "You can use 'qemu-img convert' to convert your " 1278 "image to an alternative supported format, such " 1279 "as unencrypted qcow2, or raw with the LUKS " 1280 "format instead.\n"); 1281 ret = -ENOSYS; 1282 goto fail; 1283 } 1284 1285 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1286 s->crypt_physical_offset = false; 1287 } else { 1288 /* Assuming LUKS and any future crypt methods we 1289 * add will all use physical offsets, due to the 1290 * fact that the alternative is insecure... */ 1291 s->crypt_physical_offset = true; 1292 } 1293 1294 bs->encrypted = true; 1295 } 1296 1297 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1298 s->l2_size = 1 << s->l2_bits; 1299 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1300 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1301 s->refcount_block_size = 1 << s->refcount_block_bits; 1302 bs->total_sectors = header.size / 512; 1303 s->csize_shift = (62 - (s->cluster_bits - 8)); 1304 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1305 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1306 1307 s->refcount_table_offset = header.refcount_table_offset; 1308 s->refcount_table_size = 1309 header.refcount_table_clusters << (s->cluster_bits - 3); 1310 1311 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 1312 error_setg(errp, "Reference count table too large"); 1313 ret = -EINVAL; 1314 goto fail; 1315 } 1316 1317 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1318 error_setg(errp, "Image does not contain a reference count table"); 1319 ret = -EINVAL; 1320 goto fail; 1321 } 1322 1323 ret = validate_table_offset(bs, s->refcount_table_offset, 1324 s->refcount_table_size, sizeof(uint64_t)); 1325 if (ret < 0) { 1326 error_setg(errp, "Invalid reference count table offset"); 1327 goto fail; 1328 } 1329 1330 /* Snapshot table offset/length */ 1331 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1332 error_setg(errp, "Too many snapshots"); 1333 ret = -EINVAL; 1334 goto fail; 1335 } 1336 1337 ret = validate_table_offset(bs, header.snapshots_offset, 1338 header.nb_snapshots, 1339 sizeof(QCowSnapshotHeader)); 1340 if (ret < 0) { 1341 error_setg(errp, "Invalid snapshot table offset"); 1342 goto fail; 1343 } 1344 1345 /* read the level 1 table */ 1346 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1347 error_setg(errp, "Active L1 table too large"); 1348 ret = -EFBIG; 1349 goto fail; 1350 } 1351 s->l1_size = header.l1_size; 1352 1353 l1_vm_state_index = size_to_l1(s, header.size); 1354 if (l1_vm_state_index > INT_MAX) { 1355 error_setg(errp, "Image is too big"); 1356 ret = -EFBIG; 1357 goto fail; 1358 } 1359 s->l1_vm_state_index = l1_vm_state_index; 1360 1361 /* the L1 table must contain at least enough entries to put 1362 header.size bytes */ 1363 if (s->l1_size < s->l1_vm_state_index) { 1364 error_setg(errp, "L1 table is too small"); 1365 ret = -EINVAL; 1366 goto fail; 1367 } 1368 1369 ret = validate_table_offset(bs, header.l1_table_offset, 1370 header.l1_size, sizeof(uint64_t)); 1371 if (ret < 0) { 1372 error_setg(errp, "Invalid L1 table offset"); 1373 goto fail; 1374 } 1375 s->l1_table_offset = header.l1_table_offset; 1376 1377 1378 if (s->l1_size > 0) { 1379 s->l1_table = qemu_try_blockalign(bs->file->bs, 1380 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1381 if (s->l1_table == NULL) { 1382 error_setg(errp, "Could not allocate L1 table"); 1383 ret = -ENOMEM; 1384 goto fail; 1385 } 1386 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1387 s->l1_size * sizeof(uint64_t)); 1388 if (ret < 0) { 1389 error_setg_errno(errp, -ret, "Could not read L1 table"); 1390 goto fail; 1391 } 1392 for(i = 0;i < s->l1_size; i++) { 1393 be64_to_cpus(&s->l1_table[i]); 1394 } 1395 } 1396 1397 /* Parse driver-specific options */ 1398 ret = qcow2_update_options(bs, options, flags, errp); 1399 if (ret < 0) { 1400 goto fail; 1401 } 1402 1403 s->cluster_cache_offset = -1; 1404 s->flags = flags; 1405 1406 ret = qcow2_refcount_init(bs); 1407 if (ret != 0) { 1408 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1409 goto fail; 1410 } 1411 1412 QLIST_INIT(&s->cluster_allocs); 1413 QTAILQ_INIT(&s->discards); 1414 1415 /* read qcow2 extensions */ 1416 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1417 flags, &update_header, &local_err)) { 1418 error_propagate(errp, local_err); 1419 ret = -EINVAL; 1420 goto fail; 1421 } 1422 1423 /* qcow2_read_extension may have set up the crypto context 1424 * if the crypt method needs a header region, some methods 1425 * don't need header extensions, so must check here 1426 */ 1427 if (s->crypt_method_header && !s->crypto) { 1428 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1429 unsigned int cflags = 0; 1430 if (flags & BDRV_O_NO_IO) { 1431 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1432 } 1433 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1434 NULL, NULL, cflags, errp); 1435 if (!s->crypto) { 1436 ret = -EINVAL; 1437 goto fail; 1438 } 1439 } else if (!(flags & BDRV_O_NO_IO)) { 1440 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1441 s->crypt_method_header); 1442 ret = -EINVAL; 1443 goto fail; 1444 } 1445 } 1446 1447 /* read the backing file name */ 1448 if (header.backing_file_offset != 0) { 1449 len = header.backing_file_size; 1450 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1451 len >= sizeof(bs->backing_file)) { 1452 error_setg(errp, "Backing file name too long"); 1453 ret = -EINVAL; 1454 goto fail; 1455 } 1456 ret = bdrv_pread(bs->file, header.backing_file_offset, 1457 bs->backing_file, len); 1458 if (ret < 0) { 1459 error_setg_errno(errp, -ret, "Could not read backing file name"); 1460 goto fail; 1461 } 1462 bs->backing_file[len] = '\0'; 1463 s->image_backing_file = g_strdup(bs->backing_file); 1464 } 1465 1466 /* Internal snapshots */ 1467 s->snapshots_offset = header.snapshots_offset; 1468 s->nb_snapshots = header.nb_snapshots; 1469 1470 ret = qcow2_read_snapshots(bs); 1471 if (ret < 0) { 1472 error_setg_errno(errp, -ret, "Could not read snapshots"); 1473 goto fail; 1474 } 1475 1476 /* Clear unknown autoclear feature bits */ 1477 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1478 update_header = 1479 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1480 if (update_header) { 1481 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1482 } 1483 1484 if (qcow2_load_dirty_bitmaps(bs, &local_err)) { 1485 update_header = false; 1486 } 1487 if (local_err != NULL) { 1488 error_propagate(errp, local_err); 1489 ret = -EINVAL; 1490 goto fail; 1491 } 1492 1493 if (update_header) { 1494 ret = qcow2_update_header(bs); 1495 if (ret < 0) { 1496 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1497 goto fail; 1498 } 1499 } 1500 1501 /* Initialise locks */ 1502 qemu_co_mutex_init(&s->lock); 1503 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1504 1505 /* Repair image if dirty */ 1506 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1507 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1508 BdrvCheckResult result = {0}; 1509 1510 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1511 if (ret < 0 || result.check_errors) { 1512 if (ret >= 0) { 1513 ret = -EIO; 1514 } 1515 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1516 goto fail; 1517 } 1518 } 1519 1520 #ifdef DEBUG_ALLOC 1521 { 1522 BdrvCheckResult result = {0}; 1523 qcow2_check_refcounts(bs, &result, 0); 1524 } 1525 #endif 1526 return ret; 1527 1528 fail: 1529 g_free(s->unknown_header_fields); 1530 cleanup_unknown_header_ext(bs); 1531 qcow2_free_snapshots(bs); 1532 qcow2_refcount_close(bs); 1533 qemu_vfree(s->l1_table); 1534 /* else pre-write overlap checks in cache_destroy may crash */ 1535 s->l1_table = NULL; 1536 cache_clean_timer_del(bs); 1537 if (s->l2_table_cache) { 1538 qcow2_cache_destroy(s->l2_table_cache); 1539 } 1540 if (s->refcount_block_cache) { 1541 qcow2_cache_destroy(s->refcount_block_cache); 1542 } 1543 qcrypto_block_free(s->crypto); 1544 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1545 return ret; 1546 } 1547 1548 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1549 Error **errp) 1550 { 1551 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1552 false, errp); 1553 if (!bs->file) { 1554 return -EINVAL; 1555 } 1556 1557 return qcow2_do_open(bs, options, flags, errp); 1558 } 1559 1560 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1561 { 1562 BDRVQcow2State *s = bs->opaque; 1563 1564 if (bs->encrypted) { 1565 /* Encryption works on a sector granularity */ 1566 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 1567 } 1568 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1569 bs->bl.pdiscard_alignment = s->cluster_size; 1570 } 1571 1572 static int qcow2_reopen_prepare(BDRVReopenState *state, 1573 BlockReopenQueue *queue, Error **errp) 1574 { 1575 Qcow2ReopenState *r; 1576 int ret; 1577 1578 r = g_new0(Qcow2ReopenState, 1); 1579 state->opaque = r; 1580 1581 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1582 state->flags, errp); 1583 if (ret < 0) { 1584 goto fail; 1585 } 1586 1587 /* We need to write out any unwritten data if we reopen read-only. */ 1588 if ((state->flags & BDRV_O_RDWR) == 0) { 1589 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1590 if (ret < 0) { 1591 goto fail; 1592 } 1593 1594 ret = bdrv_flush(state->bs); 1595 if (ret < 0) { 1596 goto fail; 1597 } 1598 1599 ret = qcow2_mark_clean(state->bs); 1600 if (ret < 0) { 1601 goto fail; 1602 } 1603 } 1604 1605 return 0; 1606 1607 fail: 1608 qcow2_update_options_abort(state->bs, r); 1609 g_free(r); 1610 return ret; 1611 } 1612 1613 static void qcow2_reopen_commit(BDRVReopenState *state) 1614 { 1615 qcow2_update_options_commit(state->bs, state->opaque); 1616 g_free(state->opaque); 1617 } 1618 1619 static void qcow2_reopen_abort(BDRVReopenState *state) 1620 { 1621 qcow2_update_options_abort(state->bs, state->opaque); 1622 g_free(state->opaque); 1623 } 1624 1625 static void qcow2_join_options(QDict *options, QDict *old_options) 1626 { 1627 bool has_new_overlap_template = 1628 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1629 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1630 bool has_new_total_cache_size = 1631 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1632 bool has_all_cache_options; 1633 1634 /* New overlap template overrides all old overlap options */ 1635 if (has_new_overlap_template) { 1636 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1637 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1638 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1639 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1640 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1641 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1642 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1643 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1644 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1645 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1646 } 1647 1648 /* New total cache size overrides all old options */ 1649 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1650 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1651 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1652 } 1653 1654 qdict_join(options, old_options, false); 1655 1656 /* 1657 * If after merging all cache size options are set, an old total size is 1658 * overwritten. Do keep all options, however, if all three are new. The 1659 * resulting error message is what we want to happen. 1660 */ 1661 has_all_cache_options = 1662 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1663 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1664 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1665 1666 if (has_all_cache_options && !has_new_total_cache_size) { 1667 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1668 } 1669 } 1670 1671 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1672 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1673 { 1674 BDRVQcow2State *s = bs->opaque; 1675 uint64_t cluster_offset; 1676 int index_in_cluster, ret; 1677 unsigned int bytes; 1678 int64_t status = 0; 1679 1680 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE); 1681 qemu_co_mutex_lock(&s->lock); 1682 ret = qcow2_get_cluster_offset(bs, sector_num << BDRV_SECTOR_BITS, &bytes, 1683 &cluster_offset); 1684 qemu_co_mutex_unlock(&s->lock); 1685 if (ret < 0) { 1686 return ret; 1687 } 1688 1689 *pnum = bytes >> BDRV_SECTOR_BITS; 1690 1691 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1692 !s->crypto) { 1693 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1694 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1695 *file = bs->file->bs; 1696 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1697 } 1698 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1699 status |= BDRV_BLOCK_ZERO; 1700 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1701 status |= BDRV_BLOCK_DATA; 1702 } 1703 return status; 1704 } 1705 1706 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1707 uint64_t bytes, QEMUIOVector *qiov, 1708 int flags) 1709 { 1710 BDRVQcow2State *s = bs->opaque; 1711 int offset_in_cluster; 1712 int ret; 1713 unsigned int cur_bytes; /* number of bytes in current iteration */ 1714 uint64_t cluster_offset = 0; 1715 uint64_t bytes_done = 0; 1716 QEMUIOVector hd_qiov; 1717 uint8_t *cluster_data = NULL; 1718 1719 qemu_iovec_init(&hd_qiov, qiov->niov); 1720 1721 qemu_co_mutex_lock(&s->lock); 1722 1723 while (bytes != 0) { 1724 1725 /* prepare next request */ 1726 cur_bytes = MIN(bytes, INT_MAX); 1727 if (s->crypto) { 1728 cur_bytes = MIN(cur_bytes, 1729 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1730 } 1731 1732 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1733 if (ret < 0) { 1734 goto fail; 1735 } 1736 1737 offset_in_cluster = offset_into_cluster(s, offset); 1738 1739 qemu_iovec_reset(&hd_qiov); 1740 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1741 1742 switch (ret) { 1743 case QCOW2_CLUSTER_UNALLOCATED: 1744 1745 if (bs->backing) { 1746 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1747 qemu_co_mutex_unlock(&s->lock); 1748 ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, 1749 &hd_qiov, 0); 1750 qemu_co_mutex_lock(&s->lock); 1751 if (ret < 0) { 1752 goto fail; 1753 } 1754 } else { 1755 /* Note: in this case, no need to wait */ 1756 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1757 } 1758 break; 1759 1760 case QCOW2_CLUSTER_ZERO_PLAIN: 1761 case QCOW2_CLUSTER_ZERO_ALLOC: 1762 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1763 break; 1764 1765 case QCOW2_CLUSTER_COMPRESSED: 1766 /* add AIO support for compressed blocks ? */ 1767 ret = qcow2_decompress_cluster(bs, cluster_offset); 1768 if (ret < 0) { 1769 goto fail; 1770 } 1771 1772 qemu_iovec_from_buf(&hd_qiov, 0, 1773 s->cluster_cache + offset_in_cluster, 1774 cur_bytes); 1775 break; 1776 1777 case QCOW2_CLUSTER_NORMAL: 1778 if ((cluster_offset & 511) != 0) { 1779 ret = -EIO; 1780 goto fail; 1781 } 1782 1783 if (bs->encrypted) { 1784 assert(s->crypto); 1785 1786 /* 1787 * For encrypted images, read everything into a temporary 1788 * contiguous buffer on which the AES functions can work. 1789 */ 1790 if (!cluster_data) { 1791 cluster_data = 1792 qemu_try_blockalign(bs->file->bs, 1793 QCOW_MAX_CRYPT_CLUSTERS 1794 * s->cluster_size); 1795 if (cluster_data == NULL) { 1796 ret = -ENOMEM; 1797 goto fail; 1798 } 1799 } 1800 1801 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1802 qemu_iovec_reset(&hd_qiov); 1803 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1804 } 1805 1806 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1807 qemu_co_mutex_unlock(&s->lock); 1808 ret = bdrv_co_preadv(bs->file, 1809 cluster_offset + offset_in_cluster, 1810 cur_bytes, &hd_qiov, 0); 1811 qemu_co_mutex_lock(&s->lock); 1812 if (ret < 0) { 1813 goto fail; 1814 } 1815 if (bs->encrypted) { 1816 assert(s->crypto); 1817 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1818 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1819 if (qcrypto_block_decrypt(s->crypto, 1820 (s->crypt_physical_offset ? 1821 cluster_offset + offset_in_cluster : 1822 offset), 1823 cluster_data, 1824 cur_bytes, 1825 NULL) < 0) { 1826 ret = -EIO; 1827 goto fail; 1828 } 1829 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1830 } 1831 break; 1832 1833 default: 1834 g_assert_not_reached(); 1835 ret = -EIO; 1836 goto fail; 1837 } 1838 1839 bytes -= cur_bytes; 1840 offset += cur_bytes; 1841 bytes_done += cur_bytes; 1842 } 1843 ret = 0; 1844 1845 fail: 1846 qemu_co_mutex_unlock(&s->lock); 1847 1848 qemu_iovec_destroy(&hd_qiov); 1849 qemu_vfree(cluster_data); 1850 1851 return ret; 1852 } 1853 1854 /* Check if it's possible to merge a write request with the writing of 1855 * the data from the COW regions */ 1856 static bool merge_cow(uint64_t offset, unsigned bytes, 1857 QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) 1858 { 1859 QCowL2Meta *m; 1860 1861 for (m = l2meta; m != NULL; m = m->next) { 1862 /* If both COW regions are empty then there's nothing to merge */ 1863 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 1864 continue; 1865 } 1866 1867 /* The data (middle) region must be immediately after the 1868 * start region */ 1869 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 1870 continue; 1871 } 1872 1873 /* The end region must be immediately after the data (middle) 1874 * region */ 1875 if (m->offset + m->cow_end.offset != offset + bytes) { 1876 continue; 1877 } 1878 1879 /* Make sure that adding both COW regions to the QEMUIOVector 1880 * does not exceed IOV_MAX */ 1881 if (hd_qiov->niov > IOV_MAX - 2) { 1882 continue; 1883 } 1884 1885 m->data_qiov = hd_qiov; 1886 return true; 1887 } 1888 1889 return false; 1890 } 1891 1892 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 1893 uint64_t bytes, QEMUIOVector *qiov, 1894 int flags) 1895 { 1896 BDRVQcow2State *s = bs->opaque; 1897 int offset_in_cluster; 1898 int ret; 1899 unsigned int cur_bytes; /* number of sectors in current iteration */ 1900 uint64_t cluster_offset; 1901 QEMUIOVector hd_qiov; 1902 uint64_t bytes_done = 0; 1903 uint8_t *cluster_data = NULL; 1904 QCowL2Meta *l2meta = NULL; 1905 1906 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 1907 1908 qemu_iovec_init(&hd_qiov, qiov->niov); 1909 1910 s->cluster_cache_offset = -1; /* disable compressed cache */ 1911 1912 qemu_co_mutex_lock(&s->lock); 1913 1914 while (bytes != 0) { 1915 1916 l2meta = NULL; 1917 1918 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1919 offset_in_cluster = offset_into_cluster(s, offset); 1920 cur_bytes = MIN(bytes, INT_MAX); 1921 if (bs->encrypted) { 1922 cur_bytes = MIN(cur_bytes, 1923 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 1924 - offset_in_cluster); 1925 } 1926 1927 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 1928 &cluster_offset, &l2meta); 1929 if (ret < 0) { 1930 goto fail; 1931 } 1932 1933 assert((cluster_offset & 511) == 0); 1934 1935 qemu_iovec_reset(&hd_qiov); 1936 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1937 1938 if (bs->encrypted) { 1939 assert(s->crypto); 1940 if (!cluster_data) { 1941 cluster_data = qemu_try_blockalign(bs->file->bs, 1942 QCOW_MAX_CRYPT_CLUSTERS 1943 * s->cluster_size); 1944 if (cluster_data == NULL) { 1945 ret = -ENOMEM; 1946 goto fail; 1947 } 1948 } 1949 1950 assert(hd_qiov.size <= 1951 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1952 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1953 1954 if (qcrypto_block_encrypt(s->crypto, 1955 (s->crypt_physical_offset ? 1956 cluster_offset + offset_in_cluster : 1957 offset), 1958 cluster_data, 1959 cur_bytes, NULL) < 0) { 1960 ret = -EIO; 1961 goto fail; 1962 } 1963 1964 qemu_iovec_reset(&hd_qiov); 1965 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1966 } 1967 1968 ret = qcow2_pre_write_overlap_check(bs, 0, 1969 cluster_offset + offset_in_cluster, cur_bytes); 1970 if (ret < 0) { 1971 goto fail; 1972 } 1973 1974 /* If we need to do COW, check if it's possible to merge the 1975 * writing of the guest data together with that of the COW regions. 1976 * If it's not possible (or not necessary) then write the 1977 * guest data now. */ 1978 if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { 1979 qemu_co_mutex_unlock(&s->lock); 1980 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1981 trace_qcow2_writev_data(qemu_coroutine_self(), 1982 cluster_offset + offset_in_cluster); 1983 ret = bdrv_co_pwritev(bs->file, 1984 cluster_offset + offset_in_cluster, 1985 cur_bytes, &hd_qiov, 0); 1986 qemu_co_mutex_lock(&s->lock); 1987 if (ret < 0) { 1988 goto fail; 1989 } 1990 } 1991 1992 while (l2meta != NULL) { 1993 QCowL2Meta *next; 1994 1995 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1996 if (ret < 0) { 1997 goto fail; 1998 } 1999 2000 /* Take the request off the list of running requests */ 2001 if (l2meta->nb_clusters != 0) { 2002 QLIST_REMOVE(l2meta, next_in_flight); 2003 } 2004 2005 qemu_co_queue_restart_all(&l2meta->dependent_requests); 2006 2007 next = l2meta->next; 2008 g_free(l2meta); 2009 l2meta = next; 2010 } 2011 2012 bytes -= cur_bytes; 2013 offset += cur_bytes; 2014 bytes_done += cur_bytes; 2015 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2016 } 2017 ret = 0; 2018 2019 fail: 2020 while (l2meta != NULL) { 2021 QCowL2Meta *next; 2022 2023 if (l2meta->nb_clusters != 0) { 2024 QLIST_REMOVE(l2meta, next_in_flight); 2025 } 2026 qemu_co_queue_restart_all(&l2meta->dependent_requests); 2027 2028 next = l2meta->next; 2029 g_free(l2meta); 2030 l2meta = next; 2031 } 2032 2033 qemu_co_mutex_unlock(&s->lock); 2034 2035 qemu_iovec_destroy(&hd_qiov); 2036 qemu_vfree(cluster_data); 2037 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2038 2039 return ret; 2040 } 2041 2042 static int qcow2_inactivate(BlockDriverState *bs) 2043 { 2044 BDRVQcow2State *s = bs->opaque; 2045 int ret, result = 0; 2046 Error *local_err = NULL; 2047 2048 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2049 if (local_err != NULL) { 2050 result = -EINVAL; 2051 error_report_err(local_err); 2052 error_report("Persistent bitmaps are lost for node '%s'", 2053 bdrv_get_device_or_node_name(bs)); 2054 } 2055 2056 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2057 if (ret) { 2058 result = ret; 2059 error_report("Failed to flush the L2 table cache: %s", 2060 strerror(-ret)); 2061 } 2062 2063 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2064 if (ret) { 2065 result = ret; 2066 error_report("Failed to flush the refcount block cache: %s", 2067 strerror(-ret)); 2068 } 2069 2070 if (result == 0) { 2071 qcow2_mark_clean(bs); 2072 } 2073 2074 return result; 2075 } 2076 2077 static void qcow2_close(BlockDriverState *bs) 2078 { 2079 BDRVQcow2State *s = bs->opaque; 2080 qemu_vfree(s->l1_table); 2081 /* else pre-write overlap checks in cache_destroy may crash */ 2082 s->l1_table = NULL; 2083 2084 if (!(s->flags & BDRV_O_INACTIVE)) { 2085 qcow2_inactivate(bs); 2086 } 2087 2088 cache_clean_timer_del(bs); 2089 qcow2_cache_destroy(s->l2_table_cache); 2090 qcow2_cache_destroy(s->refcount_block_cache); 2091 2092 qcrypto_block_free(s->crypto); 2093 s->crypto = NULL; 2094 2095 g_free(s->unknown_header_fields); 2096 cleanup_unknown_header_ext(bs); 2097 2098 g_free(s->image_backing_file); 2099 g_free(s->image_backing_format); 2100 2101 g_free(s->cluster_cache); 2102 qemu_vfree(s->cluster_data); 2103 qcow2_refcount_close(bs); 2104 qcow2_free_snapshots(bs); 2105 } 2106 2107 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 2108 { 2109 BDRVQcow2State *s = bs->opaque; 2110 int flags = s->flags; 2111 QCryptoBlock *crypto = NULL; 2112 QDict *options; 2113 Error *local_err = NULL; 2114 int ret; 2115 2116 /* 2117 * Backing files are read-only which makes all of their metadata immutable, 2118 * that means we don't have to worry about reopening them here. 2119 */ 2120 2121 crypto = s->crypto; 2122 s->crypto = NULL; 2123 2124 qcow2_close(bs); 2125 2126 memset(s, 0, sizeof(BDRVQcow2State)); 2127 options = qdict_clone_shallow(bs->options); 2128 2129 flags &= ~BDRV_O_INACTIVE; 2130 ret = qcow2_do_open(bs, options, flags, &local_err); 2131 QDECREF(options); 2132 if (local_err) { 2133 error_propagate(errp, local_err); 2134 error_prepend(errp, "Could not reopen qcow2 layer: "); 2135 bs->drv = NULL; 2136 return; 2137 } else if (ret < 0) { 2138 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2139 bs->drv = NULL; 2140 return; 2141 } 2142 2143 s->crypto = crypto; 2144 } 2145 2146 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2147 size_t len, size_t buflen) 2148 { 2149 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2150 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2151 2152 if (buflen < ext_len) { 2153 return -ENOSPC; 2154 } 2155 2156 *ext_backing_fmt = (QCowExtension) { 2157 .magic = cpu_to_be32(magic), 2158 .len = cpu_to_be32(len), 2159 }; 2160 2161 if (len) { 2162 memcpy(buf + sizeof(QCowExtension), s, len); 2163 } 2164 2165 return ext_len; 2166 } 2167 2168 /* 2169 * Updates the qcow2 header, including the variable length parts of it, i.e. 2170 * the backing file name and all extensions. qcow2 was not designed to allow 2171 * such changes, so if we run out of space (we can only use the first cluster) 2172 * this function may fail. 2173 * 2174 * Returns 0 on success, -errno in error cases. 2175 */ 2176 int qcow2_update_header(BlockDriverState *bs) 2177 { 2178 BDRVQcow2State *s = bs->opaque; 2179 QCowHeader *header; 2180 char *buf; 2181 size_t buflen = s->cluster_size; 2182 int ret; 2183 uint64_t total_size; 2184 uint32_t refcount_table_clusters; 2185 size_t header_length; 2186 Qcow2UnknownHeaderExtension *uext; 2187 2188 buf = qemu_blockalign(bs, buflen); 2189 2190 /* Header structure */ 2191 header = (QCowHeader*) buf; 2192 2193 if (buflen < sizeof(*header)) { 2194 ret = -ENOSPC; 2195 goto fail; 2196 } 2197 2198 header_length = sizeof(*header) + s->unknown_header_fields_size; 2199 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2200 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2201 2202 *header = (QCowHeader) { 2203 /* Version 2 fields */ 2204 .magic = cpu_to_be32(QCOW_MAGIC), 2205 .version = cpu_to_be32(s->qcow_version), 2206 .backing_file_offset = 0, 2207 .backing_file_size = 0, 2208 .cluster_bits = cpu_to_be32(s->cluster_bits), 2209 .size = cpu_to_be64(total_size), 2210 .crypt_method = cpu_to_be32(s->crypt_method_header), 2211 .l1_size = cpu_to_be32(s->l1_size), 2212 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2213 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2214 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2215 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2216 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2217 2218 /* Version 3 fields */ 2219 .incompatible_features = cpu_to_be64(s->incompatible_features), 2220 .compatible_features = cpu_to_be64(s->compatible_features), 2221 .autoclear_features = cpu_to_be64(s->autoclear_features), 2222 .refcount_order = cpu_to_be32(s->refcount_order), 2223 .header_length = cpu_to_be32(header_length), 2224 }; 2225 2226 /* For older versions, write a shorter header */ 2227 switch (s->qcow_version) { 2228 case 2: 2229 ret = offsetof(QCowHeader, incompatible_features); 2230 break; 2231 case 3: 2232 ret = sizeof(*header); 2233 break; 2234 default: 2235 ret = -EINVAL; 2236 goto fail; 2237 } 2238 2239 buf += ret; 2240 buflen -= ret; 2241 memset(buf, 0, buflen); 2242 2243 /* Preserve any unknown field in the header */ 2244 if (s->unknown_header_fields_size) { 2245 if (buflen < s->unknown_header_fields_size) { 2246 ret = -ENOSPC; 2247 goto fail; 2248 } 2249 2250 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2251 buf += s->unknown_header_fields_size; 2252 buflen -= s->unknown_header_fields_size; 2253 } 2254 2255 /* Backing file format header extension */ 2256 if (s->image_backing_format) { 2257 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2258 s->image_backing_format, 2259 strlen(s->image_backing_format), 2260 buflen); 2261 if (ret < 0) { 2262 goto fail; 2263 } 2264 2265 buf += ret; 2266 buflen -= ret; 2267 } 2268 2269 /* Full disk encryption header pointer extension */ 2270 if (s->crypto_header.offset != 0) { 2271 cpu_to_be64s(&s->crypto_header.offset); 2272 cpu_to_be64s(&s->crypto_header.length); 2273 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2274 &s->crypto_header, sizeof(s->crypto_header), 2275 buflen); 2276 be64_to_cpus(&s->crypto_header.offset); 2277 be64_to_cpus(&s->crypto_header.length); 2278 if (ret < 0) { 2279 goto fail; 2280 } 2281 buf += ret; 2282 buflen -= ret; 2283 } 2284 2285 /* Feature table */ 2286 if (s->qcow_version >= 3) { 2287 Qcow2Feature features[] = { 2288 { 2289 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2290 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2291 .name = "dirty bit", 2292 }, 2293 { 2294 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2295 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2296 .name = "corrupt bit", 2297 }, 2298 { 2299 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2300 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2301 .name = "lazy refcounts", 2302 }, 2303 }; 2304 2305 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2306 features, sizeof(features), buflen); 2307 if (ret < 0) { 2308 goto fail; 2309 } 2310 buf += ret; 2311 buflen -= ret; 2312 } 2313 2314 /* Bitmap extension */ 2315 if (s->nb_bitmaps > 0) { 2316 Qcow2BitmapHeaderExt bitmaps_header = { 2317 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2318 .bitmap_directory_size = 2319 cpu_to_be64(s->bitmap_directory_size), 2320 .bitmap_directory_offset = 2321 cpu_to_be64(s->bitmap_directory_offset) 2322 }; 2323 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2324 &bitmaps_header, sizeof(bitmaps_header), 2325 buflen); 2326 if (ret < 0) { 2327 goto fail; 2328 } 2329 buf += ret; 2330 buflen -= ret; 2331 } 2332 2333 /* Keep unknown header extensions */ 2334 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2335 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2336 if (ret < 0) { 2337 goto fail; 2338 } 2339 2340 buf += ret; 2341 buflen -= ret; 2342 } 2343 2344 /* End of header extensions */ 2345 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2346 if (ret < 0) { 2347 goto fail; 2348 } 2349 2350 buf += ret; 2351 buflen -= ret; 2352 2353 /* Backing file name */ 2354 if (s->image_backing_file) { 2355 size_t backing_file_len = strlen(s->image_backing_file); 2356 2357 if (buflen < backing_file_len) { 2358 ret = -ENOSPC; 2359 goto fail; 2360 } 2361 2362 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2363 strncpy(buf, s->image_backing_file, buflen); 2364 2365 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2366 header->backing_file_size = cpu_to_be32(backing_file_len); 2367 } 2368 2369 /* Write the new header */ 2370 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2371 if (ret < 0) { 2372 goto fail; 2373 } 2374 2375 ret = 0; 2376 fail: 2377 qemu_vfree(header); 2378 return ret; 2379 } 2380 2381 static int qcow2_change_backing_file(BlockDriverState *bs, 2382 const char *backing_file, const char *backing_fmt) 2383 { 2384 BDRVQcow2State *s = bs->opaque; 2385 2386 if (backing_file && strlen(backing_file) > 1023) { 2387 return -EINVAL; 2388 } 2389 2390 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2391 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2392 2393 g_free(s->image_backing_file); 2394 g_free(s->image_backing_format); 2395 2396 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2397 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2398 2399 return qcow2_update_header(bs); 2400 } 2401 2402 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2403 { 2404 if (g_str_equal(encryptfmt, "luks")) { 2405 return QCOW_CRYPT_LUKS; 2406 } else if (g_str_equal(encryptfmt, "aes")) { 2407 return QCOW_CRYPT_AES; 2408 } else { 2409 return -EINVAL; 2410 } 2411 } 2412 2413 static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, 2414 QemuOpts *opts, Error **errp) 2415 { 2416 BDRVQcow2State *s = bs->opaque; 2417 QCryptoBlockCreateOptions *cryptoopts = NULL; 2418 QCryptoBlock *crypto = NULL; 2419 int ret = -EINVAL; 2420 QDict *options, *encryptopts; 2421 int fmt; 2422 2423 options = qemu_opts_to_qdict(opts, NULL); 2424 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 2425 QDECREF(options); 2426 2427 fmt = qcow2_crypt_method_from_format(encryptfmt); 2428 2429 switch (fmt) { 2430 case QCOW_CRYPT_LUKS: 2431 cryptoopts = block_crypto_create_opts_init( 2432 Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); 2433 break; 2434 case QCOW_CRYPT_AES: 2435 cryptoopts = block_crypto_create_opts_init( 2436 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 2437 break; 2438 default: 2439 error_setg(errp, "Unknown encryption format '%s'", encryptfmt); 2440 break; 2441 } 2442 if (!cryptoopts) { 2443 ret = -EINVAL; 2444 goto out; 2445 } 2446 s->crypt_method_header = fmt; 2447 2448 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2449 qcow2_crypto_hdr_init_func, 2450 qcow2_crypto_hdr_write_func, 2451 bs, errp); 2452 if (!crypto) { 2453 ret = -EINVAL; 2454 goto out; 2455 } 2456 2457 ret = qcow2_update_header(bs); 2458 if (ret < 0) { 2459 error_setg_errno(errp, -ret, "Could not write encryption header"); 2460 goto out; 2461 } 2462 2463 out: 2464 QDECREF(encryptopts); 2465 qcrypto_block_free(crypto); 2466 qapi_free_QCryptoBlockCreateOptions(cryptoopts); 2467 return ret; 2468 } 2469 2470 2471 typedef struct PreallocCo { 2472 BlockDriverState *bs; 2473 uint64_t offset; 2474 uint64_t new_length; 2475 2476 int ret; 2477 } PreallocCo; 2478 2479 /** 2480 * Preallocates metadata structures for data clusters between @offset (in the 2481 * guest disk) and @new_length (which is thus generally the new guest disk 2482 * size). 2483 * 2484 * Returns: 0 on success, -errno on failure. 2485 */ 2486 static void coroutine_fn preallocate_co(void *opaque) 2487 { 2488 PreallocCo *params = opaque; 2489 BlockDriverState *bs = params->bs; 2490 uint64_t offset = params->offset; 2491 uint64_t new_length = params->new_length; 2492 BDRVQcow2State *s = bs->opaque; 2493 uint64_t bytes; 2494 uint64_t host_offset = 0; 2495 unsigned int cur_bytes; 2496 int ret; 2497 QCowL2Meta *meta; 2498 2499 qemu_co_mutex_lock(&s->lock); 2500 2501 assert(offset <= new_length); 2502 bytes = new_length - offset; 2503 2504 while (bytes) { 2505 cur_bytes = MIN(bytes, INT_MAX); 2506 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2507 &host_offset, &meta); 2508 if (ret < 0) { 2509 goto done; 2510 } 2511 2512 while (meta) { 2513 QCowL2Meta *next = meta->next; 2514 2515 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2516 if (ret < 0) { 2517 qcow2_free_any_clusters(bs, meta->alloc_offset, 2518 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2519 goto done; 2520 } 2521 2522 /* There are no dependent requests, but we need to remove our 2523 * request from the list of in-flight requests */ 2524 QLIST_REMOVE(meta, next_in_flight); 2525 2526 g_free(meta); 2527 meta = next; 2528 } 2529 2530 /* TODO Preallocate data if requested */ 2531 2532 bytes -= cur_bytes; 2533 offset += cur_bytes; 2534 } 2535 2536 /* 2537 * It is expected that the image file is large enough to actually contain 2538 * all of the allocated clusters (otherwise we get failing reads after 2539 * EOF). Extend the image to the last allocated sector. 2540 */ 2541 if (host_offset != 0) { 2542 uint8_t data = 0; 2543 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2544 &data, 1); 2545 if (ret < 0) { 2546 goto done; 2547 } 2548 } 2549 2550 ret = 0; 2551 2552 done: 2553 qemu_co_mutex_unlock(&s->lock); 2554 params->ret = ret; 2555 } 2556 2557 static int preallocate(BlockDriverState *bs, 2558 uint64_t offset, uint64_t new_length) 2559 { 2560 PreallocCo params = { 2561 .bs = bs, 2562 .offset = offset, 2563 .new_length = new_length, 2564 .ret = -EINPROGRESS, 2565 }; 2566 2567 if (qemu_in_coroutine()) { 2568 preallocate_co(¶ms); 2569 } else { 2570 Coroutine *co = qemu_coroutine_create(preallocate_co, ¶ms); 2571 bdrv_coroutine_enter(bs, co); 2572 BDRV_POLL_WHILE(bs, params.ret == -EINPROGRESS); 2573 } 2574 return params.ret; 2575 } 2576 2577 /* qcow2_refcount_metadata_size: 2578 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2579 * @cluster_size: size of a cluster, in bytes 2580 * @refcount_order: refcount bits power-of-2 exponent 2581 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2582 * needs to be 2583 * 2584 * Returns: Number of bytes required for refcount blocks and table metadata. 2585 */ 2586 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2587 int refcount_order, bool generous_increase, 2588 uint64_t *refblock_count) 2589 { 2590 /* 2591 * Every host cluster is reference-counted, including metadata (even 2592 * refcount metadata is recursively included). 2593 * 2594 * An accurate formula for the size of refcount metadata size is difficult 2595 * to derive. An easier method of calculation is finding the fixed point 2596 * where no further refcount blocks or table clusters are required to 2597 * reference count every cluster. 2598 */ 2599 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2600 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2601 int64_t table = 0; /* number of refcount table clusters */ 2602 int64_t blocks = 0; /* number of refcount block clusters */ 2603 int64_t last; 2604 int64_t n = 0; 2605 2606 do { 2607 last = n; 2608 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2609 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2610 n = clusters + blocks + table; 2611 2612 if (n == last && generous_increase) { 2613 clusters += DIV_ROUND_UP(table, 2); 2614 n = 0; /* force another loop */ 2615 generous_increase = false; 2616 } 2617 } while (n != last); 2618 2619 if (refblock_count) { 2620 *refblock_count = blocks; 2621 } 2622 2623 return (blocks + table) * cluster_size; 2624 } 2625 2626 /** 2627 * qcow2_calc_prealloc_size: 2628 * @total_size: virtual disk size in bytes 2629 * @cluster_size: cluster size in bytes 2630 * @refcount_order: refcount bits power-of-2 exponent 2631 * 2632 * Returns: Total number of bytes required for the fully allocated image 2633 * (including metadata). 2634 */ 2635 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2636 size_t cluster_size, 2637 int refcount_order) 2638 { 2639 int64_t meta_size = 0; 2640 uint64_t nl1e, nl2e; 2641 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2642 2643 /* header: 1 cluster */ 2644 meta_size += cluster_size; 2645 2646 /* total size of L2 tables */ 2647 nl2e = aligned_total_size / cluster_size; 2648 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2649 meta_size += nl2e * sizeof(uint64_t); 2650 2651 /* total size of L1 tables */ 2652 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2653 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2654 meta_size += nl1e * sizeof(uint64_t); 2655 2656 /* total size of refcount table and blocks */ 2657 meta_size += qcow2_refcount_metadata_size( 2658 (meta_size + aligned_total_size) / cluster_size, 2659 cluster_size, refcount_order, false, NULL); 2660 2661 return meta_size + aligned_total_size; 2662 } 2663 2664 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2665 { 2666 size_t cluster_size; 2667 int cluster_bits; 2668 2669 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2670 DEFAULT_CLUSTER_SIZE); 2671 cluster_bits = ctz32(cluster_size); 2672 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2673 (1 << cluster_bits) != cluster_size) 2674 { 2675 error_setg(errp, "Cluster size must be a power of two between %d and " 2676 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2677 return 0; 2678 } 2679 return cluster_size; 2680 } 2681 2682 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2683 { 2684 char *buf; 2685 int ret; 2686 2687 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2688 if (!buf) { 2689 ret = 3; /* default */ 2690 } else if (!strcmp(buf, "0.10")) { 2691 ret = 2; 2692 } else if (!strcmp(buf, "1.1")) { 2693 ret = 3; 2694 } else { 2695 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2696 ret = -EINVAL; 2697 } 2698 g_free(buf); 2699 return ret; 2700 } 2701 2702 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 2703 Error **errp) 2704 { 2705 uint64_t refcount_bits; 2706 2707 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 2708 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2709 error_setg(errp, "Refcount width must be a power of two and may not " 2710 "exceed 64 bits"); 2711 return 0; 2712 } 2713 2714 if (version < 3 && refcount_bits != 16) { 2715 error_setg(errp, "Different refcount widths than 16 bits require " 2716 "compatibility level 1.1 or above (use compat=1.1 or " 2717 "greater)"); 2718 return 0; 2719 } 2720 2721 return refcount_bits; 2722 } 2723 2724 static int qcow2_create2(const char *filename, int64_t total_size, 2725 const char *backing_file, const char *backing_format, 2726 int flags, size_t cluster_size, PreallocMode prealloc, 2727 QemuOpts *opts, int version, int refcount_order, 2728 const char *encryptfmt, Error **errp) 2729 { 2730 QDict *options; 2731 2732 /* 2733 * Open the image file and write a minimal qcow2 header. 2734 * 2735 * We keep things simple and start with a zero-sized image. We also 2736 * do without refcount blocks or a L1 table for now. We'll fix the 2737 * inconsistency later. 2738 * 2739 * We do need a refcount table because growing the refcount table means 2740 * allocating two new refcount blocks - the seconds of which would be at 2741 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2742 * size for any qcow2 image. 2743 */ 2744 BlockBackend *blk; 2745 QCowHeader *header; 2746 uint64_t* refcount_table; 2747 Error *local_err = NULL; 2748 int ret; 2749 2750 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2751 int64_t prealloc_size = 2752 qcow2_calc_prealloc_size(total_size, cluster_size, refcount_order); 2753 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, prealloc_size, &error_abort); 2754 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_str(prealloc), 2755 &error_abort); 2756 } 2757 2758 ret = bdrv_create_file(filename, opts, &local_err); 2759 if (ret < 0) { 2760 error_propagate(errp, local_err); 2761 return ret; 2762 } 2763 2764 blk = blk_new_open(filename, NULL, NULL, 2765 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 2766 &local_err); 2767 if (blk == NULL) { 2768 error_propagate(errp, local_err); 2769 return -EIO; 2770 } 2771 2772 blk_set_allow_write_beyond_eof(blk, true); 2773 2774 /* Write the header */ 2775 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2776 header = g_malloc0(cluster_size); 2777 *header = (QCowHeader) { 2778 .magic = cpu_to_be32(QCOW_MAGIC), 2779 .version = cpu_to_be32(version), 2780 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 2781 .size = cpu_to_be64(0), 2782 .l1_table_offset = cpu_to_be64(0), 2783 .l1_size = cpu_to_be32(0), 2784 .refcount_table_offset = cpu_to_be64(cluster_size), 2785 .refcount_table_clusters = cpu_to_be32(1), 2786 .refcount_order = cpu_to_be32(refcount_order), 2787 .header_length = cpu_to_be32(sizeof(*header)), 2788 }; 2789 2790 /* We'll update this to correct value later */ 2791 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2792 2793 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2794 header->compatible_features |= 2795 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2796 } 2797 2798 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2799 g_free(header); 2800 if (ret < 0) { 2801 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2802 goto out; 2803 } 2804 2805 /* Write a refcount table with one refcount block */ 2806 refcount_table = g_malloc0(2 * cluster_size); 2807 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2808 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2809 g_free(refcount_table); 2810 2811 if (ret < 0) { 2812 error_setg_errno(errp, -ret, "Could not write refcount table"); 2813 goto out; 2814 } 2815 2816 blk_unref(blk); 2817 blk = NULL; 2818 2819 /* 2820 * And now open the image and make it consistent first (i.e. increase the 2821 * refcount of the cluster that is occupied by the header and the refcount 2822 * table) 2823 */ 2824 options = qdict_new(); 2825 qdict_put_str(options, "driver", "qcow2"); 2826 blk = blk_new_open(filename, NULL, options, 2827 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 2828 &local_err); 2829 if (blk == NULL) { 2830 error_propagate(errp, local_err); 2831 ret = -EIO; 2832 goto out; 2833 } 2834 2835 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2836 if (ret < 0) { 2837 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2838 "header and refcount table"); 2839 goto out; 2840 2841 } else if (ret != 0) { 2842 error_report("Huh, first cluster in empty image is already in use?"); 2843 abort(); 2844 } 2845 2846 /* Create a full header (including things like feature table) */ 2847 ret = qcow2_update_header(blk_bs(blk)); 2848 if (ret < 0) { 2849 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2850 goto out; 2851 } 2852 2853 /* Okay, now that we have a valid image, let's give it the right size */ 2854 ret = blk_truncate(blk, total_size, PREALLOC_MODE_OFF, errp); 2855 if (ret < 0) { 2856 error_prepend(errp, "Could not resize image: "); 2857 goto out; 2858 } 2859 2860 /* Want a backing file? There you go.*/ 2861 if (backing_file) { 2862 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2863 if (ret < 0) { 2864 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2865 "with format '%s'", backing_file, backing_format); 2866 goto out; 2867 } 2868 } 2869 2870 /* Want encryption? There you go. */ 2871 if (encryptfmt) { 2872 ret = qcow2_set_up_encryption(blk_bs(blk), encryptfmt, opts, errp); 2873 if (ret < 0) { 2874 goto out; 2875 } 2876 } 2877 2878 /* And if we're supposed to preallocate metadata, do that now */ 2879 if (prealloc != PREALLOC_MODE_OFF) { 2880 ret = preallocate(blk_bs(blk), 0, total_size); 2881 if (ret < 0) { 2882 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2883 goto out; 2884 } 2885 } 2886 2887 blk_unref(blk); 2888 blk = NULL; 2889 2890 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 2891 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 2892 * have to setup decryption context. We're not doing any I/O on the top 2893 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 2894 * not have effect. 2895 */ 2896 options = qdict_new(); 2897 qdict_put_str(options, "driver", "qcow2"); 2898 blk = blk_new_open(filename, NULL, options, 2899 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 2900 &local_err); 2901 if (blk == NULL) { 2902 error_propagate(errp, local_err); 2903 ret = -EIO; 2904 goto out; 2905 } 2906 2907 ret = 0; 2908 out: 2909 if (blk) { 2910 blk_unref(blk); 2911 } 2912 return ret; 2913 } 2914 2915 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2916 { 2917 char *backing_file = NULL; 2918 char *backing_fmt = NULL; 2919 char *buf = NULL; 2920 uint64_t size = 0; 2921 int flags = 0; 2922 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2923 PreallocMode prealloc; 2924 int version; 2925 uint64_t refcount_bits; 2926 int refcount_order; 2927 char *encryptfmt = NULL; 2928 Error *local_err = NULL; 2929 int ret; 2930 2931 /* Read out options */ 2932 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2933 BDRV_SECTOR_SIZE); 2934 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2935 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2936 encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 2937 if (encryptfmt) { 2938 if (qemu_opt_get(opts, BLOCK_OPT_ENCRYPT)) { 2939 error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and " 2940 BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive"); 2941 ret = -EINVAL; 2942 goto finish; 2943 } 2944 } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2945 encryptfmt = g_strdup("aes"); 2946 } 2947 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 2948 if (local_err) { 2949 error_propagate(errp, local_err); 2950 ret = -EINVAL; 2951 goto finish; 2952 } 2953 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2954 prealloc = qapi_enum_parse(&PreallocMode_lookup, buf, 2955 PREALLOC_MODE_OFF, &local_err); 2956 if (local_err) { 2957 error_propagate(errp, local_err); 2958 ret = -EINVAL; 2959 goto finish; 2960 } 2961 2962 version = qcow2_opt_get_version_del(opts, &local_err); 2963 if (local_err) { 2964 error_propagate(errp, local_err); 2965 ret = -EINVAL; 2966 goto finish; 2967 } 2968 2969 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2970 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2971 } 2972 2973 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2974 error_setg(errp, "Backing file and preallocation cannot be used at " 2975 "the same time"); 2976 ret = -EINVAL; 2977 goto finish; 2978 } 2979 2980 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2981 error_setg(errp, "Lazy refcounts only supported with compatibility " 2982 "level 1.1 and above (use compat=1.1 or greater)"); 2983 ret = -EINVAL; 2984 goto finish; 2985 } 2986 2987 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 2988 if (local_err) { 2989 error_propagate(errp, local_err); 2990 ret = -EINVAL; 2991 goto finish; 2992 } 2993 2994 refcount_order = ctz32(refcount_bits); 2995 2996 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2997 cluster_size, prealloc, opts, version, refcount_order, 2998 encryptfmt, &local_err); 2999 error_propagate(errp, local_err); 3000 3001 finish: 3002 g_free(backing_file); 3003 g_free(backing_fmt); 3004 g_free(encryptfmt); 3005 g_free(buf); 3006 return ret; 3007 } 3008 3009 3010 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3011 { 3012 int64_t nr; 3013 int res; 3014 3015 /* Clamp to image length, before checking status of underlying sectors */ 3016 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3017 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3018 } 3019 3020 if (!bytes) { 3021 return true; 3022 } 3023 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3024 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3025 } 3026 3027 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3028 int64_t offset, int bytes, BdrvRequestFlags flags) 3029 { 3030 int ret; 3031 BDRVQcow2State *s = bs->opaque; 3032 3033 uint32_t head = offset % s->cluster_size; 3034 uint32_t tail = (offset + bytes) % s->cluster_size; 3035 3036 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3037 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3038 tail = 0; 3039 } 3040 3041 if (head || tail) { 3042 uint64_t off; 3043 unsigned int nr; 3044 3045 assert(head + bytes <= s->cluster_size); 3046 3047 /* check whether remainder of cluster already reads as zero */ 3048 if (!(is_zero(bs, offset - head, head) && 3049 is_zero(bs, offset + bytes, 3050 tail ? s->cluster_size - tail : 0))) { 3051 return -ENOTSUP; 3052 } 3053 3054 qemu_co_mutex_lock(&s->lock); 3055 /* We can have new write after previous check */ 3056 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3057 bytes = s->cluster_size; 3058 nr = s->cluster_size; 3059 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3060 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3061 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3062 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3063 qemu_co_mutex_unlock(&s->lock); 3064 return -ENOTSUP; 3065 } 3066 } else { 3067 qemu_co_mutex_lock(&s->lock); 3068 } 3069 3070 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3071 3072 /* Whatever is left can use real zero clusters */ 3073 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3074 qemu_co_mutex_unlock(&s->lock); 3075 3076 return ret; 3077 } 3078 3079 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3080 int64_t offset, int bytes) 3081 { 3082 int ret; 3083 BDRVQcow2State *s = bs->opaque; 3084 3085 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3086 assert(bytes < s->cluster_size); 3087 /* Ignore partial clusters, except for the special case of the 3088 * complete partial cluster at the end of an unaligned file */ 3089 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3090 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3091 return -ENOTSUP; 3092 } 3093 } 3094 3095 qemu_co_mutex_lock(&s->lock); 3096 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3097 false); 3098 qemu_co_mutex_unlock(&s->lock); 3099 return ret; 3100 } 3101 3102 static int qcow2_truncate(BlockDriverState *bs, int64_t offset, 3103 PreallocMode prealloc, Error **errp) 3104 { 3105 BDRVQcow2State *s = bs->opaque; 3106 uint64_t old_length; 3107 int64_t new_l1_size; 3108 int ret; 3109 3110 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3111 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3112 { 3113 error_setg(errp, "Unsupported preallocation mode '%s'", 3114 PreallocMode_str(prealloc)); 3115 return -ENOTSUP; 3116 } 3117 3118 if (offset & 511) { 3119 error_setg(errp, "The new size must be a multiple of 512"); 3120 return -EINVAL; 3121 } 3122 3123 /* cannot proceed if image has snapshots */ 3124 if (s->nb_snapshots) { 3125 error_setg(errp, "Can't resize an image which has snapshots"); 3126 return -ENOTSUP; 3127 } 3128 3129 /* cannot proceed if image has bitmaps */ 3130 if (s->nb_bitmaps) { 3131 /* TODO: resize bitmaps in the image */ 3132 error_setg(errp, "Can't resize an image which has bitmaps"); 3133 return -ENOTSUP; 3134 } 3135 3136 old_length = bs->total_sectors * 512; 3137 new_l1_size = size_to_l1(s, offset); 3138 3139 if (offset < old_length) { 3140 int64_t last_cluster, old_file_size; 3141 if (prealloc != PREALLOC_MODE_OFF) { 3142 error_setg(errp, 3143 "Preallocation can't be used for shrinking an image"); 3144 return -EINVAL; 3145 } 3146 3147 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3148 old_length - ROUND_UP(offset, 3149 s->cluster_size), 3150 QCOW2_DISCARD_ALWAYS, true); 3151 if (ret < 0) { 3152 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3153 return ret; 3154 } 3155 3156 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3157 if (ret < 0) { 3158 error_setg_errno(errp, -ret, 3159 "Failed to reduce the number of L2 tables"); 3160 return ret; 3161 } 3162 3163 ret = qcow2_shrink_reftable(bs); 3164 if (ret < 0) { 3165 error_setg_errno(errp, -ret, 3166 "Failed to discard unused refblocks"); 3167 return ret; 3168 } 3169 3170 old_file_size = bdrv_getlength(bs->file->bs); 3171 if (old_file_size < 0) { 3172 error_setg_errno(errp, -old_file_size, 3173 "Failed to inquire current file length"); 3174 return old_file_size; 3175 } 3176 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3177 if (last_cluster < 0) { 3178 error_setg_errno(errp, -last_cluster, 3179 "Failed to find the last cluster"); 3180 return last_cluster; 3181 } 3182 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3183 Error *local_err = NULL; 3184 3185 bdrv_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3186 PREALLOC_MODE_OFF, &local_err); 3187 if (local_err) { 3188 warn_reportf_err(local_err, 3189 "Failed to truncate the tail of the image: "); 3190 } 3191 } 3192 } else { 3193 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3194 if (ret < 0) { 3195 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3196 return ret; 3197 } 3198 } 3199 3200 switch (prealloc) { 3201 case PREALLOC_MODE_OFF: 3202 break; 3203 3204 case PREALLOC_MODE_METADATA: 3205 ret = preallocate(bs, old_length, offset); 3206 if (ret < 0) { 3207 error_setg_errno(errp, -ret, "Preallocation failed"); 3208 return ret; 3209 } 3210 break; 3211 3212 case PREALLOC_MODE_FALLOC: 3213 case PREALLOC_MODE_FULL: 3214 { 3215 int64_t allocation_start, host_offset, guest_offset; 3216 int64_t clusters_allocated; 3217 int64_t old_file_size, new_file_size; 3218 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3219 3220 old_file_size = bdrv_getlength(bs->file->bs); 3221 if (old_file_size < 0) { 3222 error_setg_errno(errp, -old_file_size, 3223 "Failed to inquire current file length"); 3224 return old_file_size; 3225 } 3226 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3227 3228 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3229 s->cluster_size); 3230 3231 /* This is an overestimation; we will not actually allocate space for 3232 * these in the file but just make sure the new refcount structures are 3233 * able to cover them so we will not have to allocate new refblocks 3234 * while entering the data blocks in the potentially new L2 tables. 3235 * (We do not actually care where the L2 tables are placed. Maybe they 3236 * are already allocated or they can be placed somewhere before 3237 * @old_file_size. It does not matter because they will be fully 3238 * allocated automatically, so they do not need to be covered by the 3239 * preallocation. All that matters is that we will not have to allocate 3240 * new refcount structures for them.) */ 3241 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3242 s->cluster_size / sizeof(uint64_t)); 3243 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3244 * table for a potential head/tail */ 3245 nb_new_l2_tables++; 3246 3247 allocation_start = qcow2_refcount_area(bs, old_file_size, 3248 nb_new_data_clusters + 3249 nb_new_l2_tables, 3250 true, 0, 0); 3251 if (allocation_start < 0) { 3252 error_setg_errno(errp, -allocation_start, 3253 "Failed to resize refcount structures"); 3254 return allocation_start; 3255 } 3256 3257 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3258 nb_new_data_clusters); 3259 if (clusters_allocated < 0) { 3260 error_setg_errno(errp, -clusters_allocated, 3261 "Failed to allocate data clusters"); 3262 return -clusters_allocated; 3263 } 3264 3265 assert(clusters_allocated == nb_new_data_clusters); 3266 3267 /* Allocate the data area */ 3268 new_file_size = allocation_start + 3269 nb_new_data_clusters * s->cluster_size; 3270 ret = bdrv_truncate(bs->file, new_file_size, prealloc, errp); 3271 if (ret < 0) { 3272 error_prepend(errp, "Failed to resize underlying file: "); 3273 qcow2_free_clusters(bs, allocation_start, 3274 nb_new_data_clusters * s->cluster_size, 3275 QCOW2_DISCARD_OTHER); 3276 return ret; 3277 } 3278 3279 /* Create the necessary L2 entries */ 3280 host_offset = allocation_start; 3281 guest_offset = old_length; 3282 while (nb_new_data_clusters) { 3283 int64_t nb_clusters = MIN( 3284 nb_new_data_clusters, 3285 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3286 QCowL2Meta allocation = { 3287 .offset = guest_offset, 3288 .alloc_offset = host_offset, 3289 .nb_clusters = nb_clusters, 3290 }; 3291 qemu_co_queue_init(&allocation.dependent_requests); 3292 3293 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3294 if (ret < 0) { 3295 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3296 qcow2_free_clusters(bs, host_offset, 3297 nb_new_data_clusters * s->cluster_size, 3298 QCOW2_DISCARD_OTHER); 3299 return ret; 3300 } 3301 3302 guest_offset += nb_clusters * s->cluster_size; 3303 host_offset += nb_clusters * s->cluster_size; 3304 nb_new_data_clusters -= nb_clusters; 3305 } 3306 break; 3307 } 3308 3309 default: 3310 g_assert_not_reached(); 3311 } 3312 3313 if (prealloc != PREALLOC_MODE_OFF) { 3314 /* Flush metadata before actually changing the image size */ 3315 ret = bdrv_flush(bs); 3316 if (ret < 0) { 3317 error_setg_errno(errp, -ret, 3318 "Failed to flush the preallocated area to disk"); 3319 return ret; 3320 } 3321 } 3322 3323 /* write updated header.size */ 3324 offset = cpu_to_be64(offset); 3325 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3326 &offset, sizeof(uint64_t)); 3327 if (ret < 0) { 3328 error_setg_errno(errp, -ret, "Failed to update the image size"); 3329 return ret; 3330 } 3331 3332 s->l1_vm_state_index = new_l1_size; 3333 return 0; 3334 } 3335 3336 /* XXX: put compressed sectors first, then all the cluster aligned 3337 tables to avoid losing bytes in alignment */ 3338 static coroutine_fn int 3339 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 3340 uint64_t bytes, QEMUIOVector *qiov) 3341 { 3342 BDRVQcow2State *s = bs->opaque; 3343 QEMUIOVector hd_qiov; 3344 struct iovec iov; 3345 z_stream strm; 3346 int ret, out_len; 3347 uint8_t *buf, *out_buf; 3348 int64_t cluster_offset; 3349 3350 if (bytes == 0) { 3351 /* align end of file to a sector boundary to ease reading with 3352 sector based I/Os */ 3353 cluster_offset = bdrv_getlength(bs->file->bs); 3354 if (cluster_offset < 0) { 3355 return cluster_offset; 3356 } 3357 return bdrv_truncate(bs->file, cluster_offset, PREALLOC_MODE_OFF, NULL); 3358 } 3359 3360 if (offset_into_cluster(s, offset)) { 3361 return -EINVAL; 3362 } 3363 3364 buf = qemu_blockalign(bs, s->cluster_size); 3365 if (bytes != s->cluster_size) { 3366 if (bytes > s->cluster_size || 3367 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 3368 { 3369 qemu_vfree(buf); 3370 return -EINVAL; 3371 } 3372 /* Zero-pad last write if image size is not cluster aligned */ 3373 memset(buf + bytes, 0, s->cluster_size - bytes); 3374 } 3375 qemu_iovec_to_buf(qiov, 0, buf, bytes); 3376 3377 out_buf = g_malloc(s->cluster_size); 3378 3379 /* best compression, small window, no zlib header */ 3380 memset(&strm, 0, sizeof(strm)); 3381 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 3382 Z_DEFLATED, -12, 3383 9, Z_DEFAULT_STRATEGY); 3384 if (ret != 0) { 3385 ret = -EINVAL; 3386 goto fail; 3387 } 3388 3389 strm.avail_in = s->cluster_size; 3390 strm.next_in = (uint8_t *)buf; 3391 strm.avail_out = s->cluster_size; 3392 strm.next_out = out_buf; 3393 3394 ret = deflate(&strm, Z_FINISH); 3395 if (ret != Z_STREAM_END && ret != Z_OK) { 3396 deflateEnd(&strm); 3397 ret = -EINVAL; 3398 goto fail; 3399 } 3400 out_len = strm.next_out - out_buf; 3401 3402 deflateEnd(&strm); 3403 3404 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 3405 /* could not compress: write normal cluster */ 3406 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 3407 if (ret < 0) { 3408 goto fail; 3409 } 3410 goto success; 3411 } 3412 3413 qemu_co_mutex_lock(&s->lock); 3414 cluster_offset = 3415 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); 3416 if (!cluster_offset) { 3417 qemu_co_mutex_unlock(&s->lock); 3418 ret = -EIO; 3419 goto fail; 3420 } 3421 cluster_offset &= s->cluster_offset_mask; 3422 3423 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 3424 qemu_co_mutex_unlock(&s->lock); 3425 if (ret < 0) { 3426 goto fail; 3427 } 3428 3429 iov = (struct iovec) { 3430 .iov_base = out_buf, 3431 .iov_len = out_len, 3432 }; 3433 qemu_iovec_init_external(&hd_qiov, &iov, 1); 3434 3435 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 3436 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 3437 if (ret < 0) { 3438 goto fail; 3439 } 3440 success: 3441 ret = 0; 3442 fail: 3443 qemu_vfree(buf); 3444 g_free(out_buf); 3445 return ret; 3446 } 3447 3448 static int make_completely_empty(BlockDriverState *bs) 3449 { 3450 BDRVQcow2State *s = bs->opaque; 3451 Error *local_err = NULL; 3452 int ret, l1_clusters; 3453 int64_t offset; 3454 uint64_t *new_reftable = NULL; 3455 uint64_t rt_entry, l1_size2; 3456 struct { 3457 uint64_t l1_offset; 3458 uint64_t reftable_offset; 3459 uint32_t reftable_clusters; 3460 } QEMU_PACKED l1_ofs_rt_ofs_cls; 3461 3462 ret = qcow2_cache_empty(bs, s->l2_table_cache); 3463 if (ret < 0) { 3464 goto fail; 3465 } 3466 3467 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 3468 if (ret < 0) { 3469 goto fail; 3470 } 3471 3472 /* Refcounts will be broken utterly */ 3473 ret = qcow2_mark_dirty(bs); 3474 if (ret < 0) { 3475 goto fail; 3476 } 3477 3478 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 3479 3480 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 3481 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 3482 3483 /* After this call, neither the in-memory nor the on-disk refcount 3484 * information accurately describe the actual references */ 3485 3486 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 3487 l1_clusters * s->cluster_size, 0); 3488 if (ret < 0) { 3489 goto fail_broken_refcounts; 3490 } 3491 memset(s->l1_table, 0, l1_size2); 3492 3493 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 3494 3495 /* Overwrite enough clusters at the beginning of the sectors to place 3496 * the refcount table, a refcount block and the L1 table in; this may 3497 * overwrite parts of the existing refcount and L1 table, which is not 3498 * an issue because the dirty flag is set, complete data loss is in fact 3499 * desired and partial data loss is consequently fine as well */ 3500 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 3501 (2 + l1_clusters) * s->cluster_size, 0); 3502 /* This call (even if it failed overall) may have overwritten on-disk 3503 * refcount structures; in that case, the in-memory refcount information 3504 * will probably differ from the on-disk information which makes the BDS 3505 * unusable */ 3506 if (ret < 0) { 3507 goto fail_broken_refcounts; 3508 } 3509 3510 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 3511 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 3512 3513 /* "Create" an empty reftable (one cluster) directly after the image 3514 * header and an empty L1 table three clusters after the image header; 3515 * the cluster between those two will be used as the first refblock */ 3516 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 3517 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 3518 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 3519 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 3520 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 3521 if (ret < 0) { 3522 goto fail_broken_refcounts; 3523 } 3524 3525 s->l1_table_offset = 3 * s->cluster_size; 3526 3527 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 3528 if (!new_reftable) { 3529 ret = -ENOMEM; 3530 goto fail_broken_refcounts; 3531 } 3532 3533 s->refcount_table_offset = s->cluster_size; 3534 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 3535 s->max_refcount_table_index = 0; 3536 3537 g_free(s->refcount_table); 3538 s->refcount_table = new_reftable; 3539 new_reftable = NULL; 3540 3541 /* Now the in-memory refcount information again corresponds to the on-disk 3542 * information (reftable is empty and no refblocks (the refblock cache is 3543 * empty)); however, this means some clusters (e.g. the image header) are 3544 * referenced, but not refcounted, but the normal qcow2 code assumes that 3545 * the in-memory information is always correct */ 3546 3547 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 3548 3549 /* Enter the first refblock into the reftable */ 3550 rt_entry = cpu_to_be64(2 * s->cluster_size); 3551 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 3552 &rt_entry, sizeof(rt_entry)); 3553 if (ret < 0) { 3554 goto fail_broken_refcounts; 3555 } 3556 s->refcount_table[0] = 2 * s->cluster_size; 3557 3558 s->free_cluster_index = 0; 3559 assert(3 + l1_clusters <= s->refcount_block_size); 3560 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 3561 if (offset < 0) { 3562 ret = offset; 3563 goto fail_broken_refcounts; 3564 } else if (offset > 0) { 3565 error_report("First cluster in emptied image is in use"); 3566 abort(); 3567 } 3568 3569 /* Now finally the in-memory information corresponds to the on-disk 3570 * structures and is correct */ 3571 ret = qcow2_mark_clean(bs); 3572 if (ret < 0) { 3573 goto fail; 3574 } 3575 3576 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 3577 PREALLOC_MODE_OFF, &local_err); 3578 if (ret < 0) { 3579 error_report_err(local_err); 3580 goto fail; 3581 } 3582 3583 return 0; 3584 3585 fail_broken_refcounts: 3586 /* The BDS is unusable at this point. If we wanted to make it usable, we 3587 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 3588 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 3589 * again. However, because the functions which could have caused this error 3590 * path to be taken are used by those functions as well, it's very likely 3591 * that that sequence will fail as well. Therefore, just eject the BDS. */ 3592 bs->drv = NULL; 3593 3594 fail: 3595 g_free(new_reftable); 3596 return ret; 3597 } 3598 3599 static int qcow2_make_empty(BlockDriverState *bs) 3600 { 3601 BDRVQcow2State *s = bs->opaque; 3602 uint64_t offset, end_offset; 3603 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 3604 int l1_clusters, ret = 0; 3605 3606 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 3607 3608 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 3609 3 + l1_clusters <= s->refcount_block_size && 3610 s->crypt_method_header != QCOW_CRYPT_LUKS) { 3611 /* The following function only works for qcow2 v3 images (it 3612 * requires the dirty flag) and only as long as there are no 3613 * features that reserve extra clusters (such as snapshots, 3614 * LUKS header, or persistent bitmaps), because it completely 3615 * empties the image. Furthermore, the L1 table and three 3616 * additional clusters (image header, refcount table, one 3617 * refcount block) have to fit inside one refcount block. */ 3618 return make_completely_empty(bs); 3619 } 3620 3621 /* This fallback code simply discards every active cluster; this is slow, 3622 * but works in all cases */ 3623 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 3624 for (offset = 0; offset < end_offset; offset += step) { 3625 /* As this function is generally used after committing an external 3626 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 3627 * default action for this kind of discard is to pass the discard, 3628 * which will ideally result in an actually smaller image file, as 3629 * is probably desired. */ 3630 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 3631 QCOW2_DISCARD_SNAPSHOT, true); 3632 if (ret < 0) { 3633 break; 3634 } 3635 } 3636 3637 return ret; 3638 } 3639 3640 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 3641 { 3642 BDRVQcow2State *s = bs->opaque; 3643 int ret; 3644 3645 qemu_co_mutex_lock(&s->lock); 3646 ret = qcow2_cache_write(bs, s->l2_table_cache); 3647 if (ret < 0) { 3648 qemu_co_mutex_unlock(&s->lock); 3649 return ret; 3650 } 3651 3652 if (qcow2_need_accurate_refcounts(s)) { 3653 ret = qcow2_cache_write(bs, s->refcount_block_cache); 3654 if (ret < 0) { 3655 qemu_co_mutex_unlock(&s->lock); 3656 return ret; 3657 } 3658 } 3659 qemu_co_mutex_unlock(&s->lock); 3660 3661 return 0; 3662 } 3663 3664 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 3665 Error **errp) 3666 { 3667 Error *local_err = NULL; 3668 BlockMeasureInfo *info; 3669 uint64_t required = 0; /* bytes that contribute to required size */ 3670 uint64_t virtual_size; /* disk size as seen by guest */ 3671 uint64_t refcount_bits; 3672 uint64_t l2_tables; 3673 size_t cluster_size; 3674 int version; 3675 char *optstr; 3676 PreallocMode prealloc; 3677 bool has_backing_file; 3678 3679 /* Parse image creation options */ 3680 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 3681 if (local_err) { 3682 goto err; 3683 } 3684 3685 version = qcow2_opt_get_version_del(opts, &local_err); 3686 if (local_err) { 3687 goto err; 3688 } 3689 3690 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 3691 if (local_err) { 3692 goto err; 3693 } 3694 3695 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 3696 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 3697 PREALLOC_MODE_OFF, &local_err); 3698 g_free(optstr); 3699 if (local_err) { 3700 goto err; 3701 } 3702 3703 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 3704 has_backing_file = !!optstr; 3705 g_free(optstr); 3706 3707 virtual_size = align_offset(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 3708 cluster_size); 3709 3710 /* Check that virtual disk size is valid */ 3711 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 3712 cluster_size / sizeof(uint64_t)); 3713 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 3714 error_setg(&local_err, "The image size is too large " 3715 "(try using a larger cluster size)"); 3716 goto err; 3717 } 3718 3719 /* Account for input image */ 3720 if (in_bs) { 3721 int64_t ssize = bdrv_getlength(in_bs); 3722 if (ssize < 0) { 3723 error_setg_errno(&local_err, -ssize, 3724 "Unable to get image virtual_size"); 3725 goto err; 3726 } 3727 3728 virtual_size = align_offset(ssize, cluster_size); 3729 3730 if (has_backing_file) { 3731 /* We don't how much of the backing chain is shared by the input 3732 * image and the new image file. In the worst case the new image's 3733 * backing file has nothing in common with the input image. Be 3734 * conservative and assume all clusters need to be written. 3735 */ 3736 required = virtual_size; 3737 } else { 3738 int64_t offset; 3739 int64_t pnum = 0; 3740 3741 for (offset = 0; offset < ssize; offset += pnum) { 3742 int ret; 3743 3744 ret = bdrv_block_status_above(in_bs, NULL, offset, 3745 ssize - offset, &pnum, NULL, 3746 NULL); 3747 if (ret < 0) { 3748 error_setg_errno(&local_err, -ret, 3749 "Unable to get block status"); 3750 goto err; 3751 } 3752 3753 if (ret & BDRV_BLOCK_ZERO) { 3754 /* Skip zero regions (safe with no backing file) */ 3755 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 3756 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 3757 /* Extend pnum to end of cluster for next iteration */ 3758 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 3759 3760 /* Count clusters we've seen */ 3761 required += offset % cluster_size + pnum; 3762 } 3763 } 3764 } 3765 } 3766 3767 /* Take into account preallocation. Nothing special is needed for 3768 * PREALLOC_MODE_METADATA since metadata is always counted. 3769 */ 3770 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 3771 required = virtual_size; 3772 } 3773 3774 info = g_new(BlockMeasureInfo, 1); 3775 info->fully_allocated = 3776 qcow2_calc_prealloc_size(virtual_size, cluster_size, 3777 ctz32(refcount_bits)); 3778 3779 /* Remove data clusters that are not required. This overestimates the 3780 * required size because metadata needed for the fully allocated file is 3781 * still counted. 3782 */ 3783 info->required = info->fully_allocated - virtual_size + required; 3784 return info; 3785 3786 err: 3787 error_propagate(errp, local_err); 3788 return NULL; 3789 } 3790 3791 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3792 { 3793 BDRVQcow2State *s = bs->opaque; 3794 bdi->unallocated_blocks_are_zero = true; 3795 bdi->cluster_size = s->cluster_size; 3796 bdi->vm_state_offset = qcow2_vm_state_offset(s); 3797 return 0; 3798 } 3799 3800 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 3801 { 3802 BDRVQcow2State *s = bs->opaque; 3803 ImageInfoSpecific *spec_info; 3804 QCryptoBlockInfo *encrypt_info = NULL; 3805 3806 if (s->crypto != NULL) { 3807 encrypt_info = qcrypto_block_get_info(s->crypto, &error_abort); 3808 } 3809 3810 spec_info = g_new(ImageInfoSpecific, 1); 3811 *spec_info = (ImageInfoSpecific){ 3812 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 3813 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 3814 }; 3815 if (s->qcow_version == 2) { 3816 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 3817 .compat = g_strdup("0.10"), 3818 .refcount_bits = s->refcount_bits, 3819 }; 3820 } else if (s->qcow_version == 3) { 3821 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 3822 .compat = g_strdup("1.1"), 3823 .lazy_refcounts = s->compatible_features & 3824 QCOW2_COMPAT_LAZY_REFCOUNTS, 3825 .has_lazy_refcounts = true, 3826 .corrupt = s->incompatible_features & 3827 QCOW2_INCOMPAT_CORRUPT, 3828 .has_corrupt = true, 3829 .refcount_bits = s->refcount_bits, 3830 }; 3831 } else { 3832 /* if this assertion fails, this probably means a new version was 3833 * added without having it covered here */ 3834 assert(false); 3835 } 3836 3837 if (encrypt_info) { 3838 ImageInfoSpecificQCow2Encryption *qencrypt = 3839 g_new(ImageInfoSpecificQCow2Encryption, 1); 3840 switch (encrypt_info->format) { 3841 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 3842 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 3843 qencrypt->u.aes = encrypt_info->u.qcow; 3844 break; 3845 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 3846 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 3847 qencrypt->u.luks = encrypt_info->u.luks; 3848 break; 3849 default: 3850 abort(); 3851 } 3852 /* Since we did shallow copy above, erase any pointers 3853 * in the original info */ 3854 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 3855 qapi_free_QCryptoBlockInfo(encrypt_info); 3856 3857 spec_info->u.qcow2.data->has_encrypt = true; 3858 spec_info->u.qcow2.data->encrypt = qencrypt; 3859 } 3860 3861 return spec_info; 3862 } 3863 3864 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 3865 int64_t pos) 3866 { 3867 BDRVQcow2State *s = bs->opaque; 3868 3869 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 3870 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 3871 qiov->size, qiov, 0); 3872 } 3873 3874 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 3875 int64_t pos) 3876 { 3877 BDRVQcow2State *s = bs->opaque; 3878 3879 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 3880 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 3881 qiov->size, qiov, 0); 3882 } 3883 3884 /* 3885 * Downgrades an image's version. To achieve this, any incompatible features 3886 * have to be removed. 3887 */ 3888 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 3889 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 3890 { 3891 BDRVQcow2State *s = bs->opaque; 3892 int current_version = s->qcow_version; 3893 int ret; 3894 3895 if (target_version == current_version) { 3896 return 0; 3897 } else if (target_version > current_version) { 3898 return -EINVAL; 3899 } else if (target_version != 2) { 3900 return -EINVAL; 3901 } 3902 3903 if (s->refcount_order != 4) { 3904 error_report("compat=0.10 requires refcount_bits=16"); 3905 return -ENOTSUP; 3906 } 3907 3908 /* clear incompatible features */ 3909 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 3910 ret = qcow2_mark_clean(bs); 3911 if (ret < 0) { 3912 return ret; 3913 } 3914 } 3915 3916 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 3917 * the first place; if that happens nonetheless, returning -ENOTSUP is the 3918 * best thing to do anyway */ 3919 3920 if (s->incompatible_features) { 3921 return -ENOTSUP; 3922 } 3923 3924 /* since we can ignore compatible features, we can set them to 0 as well */ 3925 s->compatible_features = 0; 3926 /* if lazy refcounts have been used, they have already been fixed through 3927 * clearing the dirty flag */ 3928 3929 /* clearing autoclear features is trivial */ 3930 s->autoclear_features = 0; 3931 3932 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 3933 if (ret < 0) { 3934 return ret; 3935 } 3936 3937 s->qcow_version = target_version; 3938 ret = qcow2_update_header(bs); 3939 if (ret < 0) { 3940 s->qcow_version = current_version; 3941 return ret; 3942 } 3943 return 0; 3944 } 3945 3946 typedef enum Qcow2AmendOperation { 3947 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 3948 * statically initialized to so that the helper CB can discern the first 3949 * invocation from an operation change */ 3950 QCOW2_NO_OPERATION = 0, 3951 3952 QCOW2_CHANGING_REFCOUNT_ORDER, 3953 QCOW2_DOWNGRADING, 3954 } Qcow2AmendOperation; 3955 3956 typedef struct Qcow2AmendHelperCBInfo { 3957 /* The code coordinating the amend operations should only modify 3958 * these four fields; the rest will be managed by the CB */ 3959 BlockDriverAmendStatusCB *original_status_cb; 3960 void *original_cb_opaque; 3961 3962 Qcow2AmendOperation current_operation; 3963 3964 /* Total number of operations to perform (only set once) */ 3965 int total_operations; 3966 3967 /* The following fields are managed by the CB */ 3968 3969 /* Number of operations completed */ 3970 int operations_completed; 3971 3972 /* Cumulative offset of all completed operations */ 3973 int64_t offset_completed; 3974 3975 Qcow2AmendOperation last_operation; 3976 int64_t last_work_size; 3977 } Qcow2AmendHelperCBInfo; 3978 3979 static void qcow2_amend_helper_cb(BlockDriverState *bs, 3980 int64_t operation_offset, 3981 int64_t operation_work_size, void *opaque) 3982 { 3983 Qcow2AmendHelperCBInfo *info = opaque; 3984 int64_t current_work_size; 3985 int64_t projected_work_size; 3986 3987 if (info->current_operation != info->last_operation) { 3988 if (info->last_operation != QCOW2_NO_OPERATION) { 3989 info->offset_completed += info->last_work_size; 3990 info->operations_completed++; 3991 } 3992 3993 info->last_operation = info->current_operation; 3994 } 3995 3996 assert(info->total_operations > 0); 3997 assert(info->operations_completed < info->total_operations); 3998 3999 info->last_work_size = operation_work_size; 4000 4001 current_work_size = info->offset_completed + operation_work_size; 4002 4003 /* current_work_size is the total work size for (operations_completed + 1) 4004 * operations (which includes this one), so multiply it by the number of 4005 * operations not covered and divide it by the number of operations 4006 * covered to get a projection for the operations not covered */ 4007 projected_work_size = current_work_size * (info->total_operations - 4008 info->operations_completed - 1) 4009 / (info->operations_completed + 1); 4010 4011 info->original_status_cb(bs, info->offset_completed + operation_offset, 4012 current_work_size + projected_work_size, 4013 info->original_cb_opaque); 4014 } 4015 4016 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4017 BlockDriverAmendStatusCB *status_cb, 4018 void *cb_opaque) 4019 { 4020 BDRVQcow2State *s = bs->opaque; 4021 int old_version = s->qcow_version, new_version = old_version; 4022 uint64_t new_size = 0; 4023 const char *backing_file = NULL, *backing_format = NULL; 4024 bool lazy_refcounts = s->use_lazy_refcounts; 4025 const char *compat = NULL; 4026 uint64_t cluster_size = s->cluster_size; 4027 bool encrypt; 4028 int encformat; 4029 int refcount_bits = s->refcount_bits; 4030 Error *local_err = NULL; 4031 int ret; 4032 QemuOptDesc *desc = opts->list->desc; 4033 Qcow2AmendHelperCBInfo helper_cb_info; 4034 4035 while (desc && desc->name) { 4036 if (!qemu_opt_find(opts, desc->name)) { 4037 /* only change explicitly defined options */ 4038 desc++; 4039 continue; 4040 } 4041 4042 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4043 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4044 if (!compat) { 4045 /* preserve default */ 4046 } else if (!strcmp(compat, "0.10")) { 4047 new_version = 2; 4048 } else if (!strcmp(compat, "1.1")) { 4049 new_version = 3; 4050 } else { 4051 error_report("Unknown compatibility level %s", compat); 4052 return -EINVAL; 4053 } 4054 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4055 error_report("Cannot change preallocation mode"); 4056 return -ENOTSUP; 4057 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4058 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4059 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4060 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4061 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4062 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4063 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4064 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4065 !!s->crypto); 4066 4067 if (encrypt != !!s->crypto) { 4068 error_report("Changing the encryption flag is not supported"); 4069 return -ENOTSUP; 4070 } 4071 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4072 encformat = qcow2_crypt_method_from_format( 4073 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4074 4075 if (encformat != s->crypt_method_header) { 4076 error_report("Changing the encryption format is not supported"); 4077 return -ENOTSUP; 4078 } 4079 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4080 error_report("Changing the encryption parameters is not supported"); 4081 return -ENOTSUP; 4082 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4083 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4084 cluster_size); 4085 if (cluster_size != s->cluster_size) { 4086 error_report("Changing the cluster size is not supported"); 4087 return -ENOTSUP; 4088 } 4089 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4090 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4091 lazy_refcounts); 4092 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4093 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4094 refcount_bits); 4095 4096 if (refcount_bits <= 0 || refcount_bits > 64 || 4097 !is_power_of_2(refcount_bits)) 4098 { 4099 error_report("Refcount width must be a power of two and may " 4100 "not exceed 64 bits"); 4101 return -EINVAL; 4102 } 4103 } else { 4104 /* if this point is reached, this probably means a new option was 4105 * added without having it covered here */ 4106 abort(); 4107 } 4108 4109 desc++; 4110 } 4111 4112 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4113 .original_status_cb = status_cb, 4114 .original_cb_opaque = cb_opaque, 4115 .total_operations = (new_version < old_version) 4116 + (s->refcount_bits != refcount_bits) 4117 }; 4118 4119 /* Upgrade first (some features may require compat=1.1) */ 4120 if (new_version > old_version) { 4121 s->qcow_version = new_version; 4122 ret = qcow2_update_header(bs); 4123 if (ret < 0) { 4124 s->qcow_version = old_version; 4125 return ret; 4126 } 4127 } 4128 4129 if (s->refcount_bits != refcount_bits) { 4130 int refcount_order = ctz32(refcount_bits); 4131 4132 if (new_version < 3 && refcount_bits != 16) { 4133 error_report("Different refcount widths than 16 bits require " 4134 "compatibility level 1.1 or above (use compat=1.1 or " 4135 "greater)"); 4136 return -EINVAL; 4137 } 4138 4139 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4140 ret = qcow2_change_refcount_order(bs, refcount_order, 4141 &qcow2_amend_helper_cb, 4142 &helper_cb_info, &local_err); 4143 if (ret < 0) { 4144 error_report_err(local_err); 4145 return ret; 4146 } 4147 } 4148 4149 if (backing_file || backing_format) { 4150 ret = qcow2_change_backing_file(bs, 4151 backing_file ?: s->image_backing_file, 4152 backing_format ?: s->image_backing_format); 4153 if (ret < 0) { 4154 return ret; 4155 } 4156 } 4157 4158 if (s->use_lazy_refcounts != lazy_refcounts) { 4159 if (lazy_refcounts) { 4160 if (new_version < 3) { 4161 error_report("Lazy refcounts only supported with compatibility " 4162 "level 1.1 and above (use compat=1.1 or greater)"); 4163 return -EINVAL; 4164 } 4165 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4166 ret = qcow2_update_header(bs); 4167 if (ret < 0) { 4168 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4169 return ret; 4170 } 4171 s->use_lazy_refcounts = true; 4172 } else { 4173 /* make image clean first */ 4174 ret = qcow2_mark_clean(bs); 4175 if (ret < 0) { 4176 return ret; 4177 } 4178 /* now disallow lazy refcounts */ 4179 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4180 ret = qcow2_update_header(bs); 4181 if (ret < 0) { 4182 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4183 return ret; 4184 } 4185 s->use_lazy_refcounts = false; 4186 } 4187 } 4188 4189 if (new_size) { 4190 BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); 4191 ret = blk_insert_bs(blk, bs, &local_err); 4192 if (ret < 0) { 4193 error_report_err(local_err); 4194 blk_unref(blk); 4195 return ret; 4196 } 4197 4198 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, &local_err); 4199 blk_unref(blk); 4200 if (ret < 0) { 4201 error_report_err(local_err); 4202 return ret; 4203 } 4204 } 4205 4206 /* Downgrade last (so unsupported features can be removed before) */ 4207 if (new_version < old_version) { 4208 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 4209 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 4210 &helper_cb_info); 4211 if (ret < 0) { 4212 return ret; 4213 } 4214 } 4215 4216 return 0; 4217 } 4218 4219 /* 4220 * If offset or size are negative, respectively, they will not be included in 4221 * the BLOCK_IMAGE_CORRUPTED event emitted. 4222 * fatal will be ignored for read-only BDS; corruptions found there will always 4223 * be considered non-fatal. 4224 */ 4225 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 4226 int64_t size, const char *message_format, ...) 4227 { 4228 BDRVQcow2State *s = bs->opaque; 4229 const char *node_name; 4230 char *message; 4231 va_list ap; 4232 4233 fatal = fatal && !bs->read_only; 4234 4235 if (s->signaled_corruption && 4236 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 4237 { 4238 return; 4239 } 4240 4241 va_start(ap, message_format); 4242 message = g_strdup_vprintf(message_format, ap); 4243 va_end(ap); 4244 4245 if (fatal) { 4246 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 4247 "corruption events will be suppressed\n", message); 4248 } else { 4249 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 4250 "corruption events will be suppressed\n", message); 4251 } 4252 4253 node_name = bdrv_get_node_name(bs); 4254 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 4255 *node_name != '\0', node_name, 4256 message, offset >= 0, offset, 4257 size >= 0, size, 4258 fatal, &error_abort); 4259 g_free(message); 4260 4261 if (fatal) { 4262 qcow2_mark_corrupt(bs); 4263 bs->drv = NULL; /* make BDS unusable */ 4264 } 4265 4266 s->signaled_corruption = true; 4267 } 4268 4269 static QemuOptsList qcow2_create_opts = { 4270 .name = "qcow2-create-opts", 4271 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 4272 .desc = { 4273 { 4274 .name = BLOCK_OPT_SIZE, 4275 .type = QEMU_OPT_SIZE, 4276 .help = "Virtual disk size" 4277 }, 4278 { 4279 .name = BLOCK_OPT_COMPAT_LEVEL, 4280 .type = QEMU_OPT_STRING, 4281 .help = "Compatibility level (0.10 or 1.1)" 4282 }, 4283 { 4284 .name = BLOCK_OPT_BACKING_FILE, 4285 .type = QEMU_OPT_STRING, 4286 .help = "File name of a base image" 4287 }, 4288 { 4289 .name = BLOCK_OPT_BACKING_FMT, 4290 .type = QEMU_OPT_STRING, 4291 .help = "Image format of the base image" 4292 }, 4293 { 4294 .name = BLOCK_OPT_ENCRYPT, 4295 .type = QEMU_OPT_BOOL, 4296 .help = "Encrypt the image with format 'aes'. (Deprecated " 4297 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 4298 }, 4299 { 4300 .name = BLOCK_OPT_ENCRYPT_FORMAT, 4301 .type = QEMU_OPT_STRING, 4302 .help = "Encrypt the image, format choices: 'aes', 'luks'", 4303 }, 4304 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 4305 "ID of secret providing qcow AES key or LUKS passphrase"), 4306 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 4307 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 4308 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 4309 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 4310 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 4311 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 4312 { 4313 .name = BLOCK_OPT_CLUSTER_SIZE, 4314 .type = QEMU_OPT_SIZE, 4315 .help = "qcow2 cluster size", 4316 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 4317 }, 4318 { 4319 .name = BLOCK_OPT_PREALLOC, 4320 .type = QEMU_OPT_STRING, 4321 .help = "Preallocation mode (allowed values: off, metadata, " 4322 "falloc, full)" 4323 }, 4324 { 4325 .name = BLOCK_OPT_LAZY_REFCOUNTS, 4326 .type = QEMU_OPT_BOOL, 4327 .help = "Postpone refcount updates", 4328 .def_value_str = "off" 4329 }, 4330 { 4331 .name = BLOCK_OPT_REFCOUNT_BITS, 4332 .type = QEMU_OPT_NUMBER, 4333 .help = "Width of a reference count entry in bits", 4334 .def_value_str = "16" 4335 }, 4336 { /* end of list */ } 4337 } 4338 }; 4339 4340 BlockDriver bdrv_qcow2 = { 4341 .format_name = "qcow2", 4342 .instance_size = sizeof(BDRVQcow2State), 4343 .bdrv_probe = qcow2_probe, 4344 .bdrv_open = qcow2_open, 4345 .bdrv_close = qcow2_close, 4346 .bdrv_reopen_prepare = qcow2_reopen_prepare, 4347 .bdrv_reopen_commit = qcow2_reopen_commit, 4348 .bdrv_reopen_abort = qcow2_reopen_abort, 4349 .bdrv_join_options = qcow2_join_options, 4350 .bdrv_child_perm = bdrv_format_default_perms, 4351 .bdrv_create = qcow2_create, 4352 .bdrv_has_zero_init = bdrv_has_zero_init_1, 4353 .bdrv_co_get_block_status = qcow2_co_get_block_status, 4354 4355 .bdrv_co_preadv = qcow2_co_preadv, 4356 .bdrv_co_pwritev = qcow2_co_pwritev, 4357 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 4358 4359 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 4360 .bdrv_co_pdiscard = qcow2_co_pdiscard, 4361 .bdrv_truncate = qcow2_truncate, 4362 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 4363 .bdrv_make_empty = qcow2_make_empty, 4364 4365 .bdrv_snapshot_create = qcow2_snapshot_create, 4366 .bdrv_snapshot_goto = qcow2_snapshot_goto, 4367 .bdrv_snapshot_delete = qcow2_snapshot_delete, 4368 .bdrv_snapshot_list = qcow2_snapshot_list, 4369 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 4370 .bdrv_measure = qcow2_measure, 4371 .bdrv_get_info = qcow2_get_info, 4372 .bdrv_get_specific_info = qcow2_get_specific_info, 4373 4374 .bdrv_save_vmstate = qcow2_save_vmstate, 4375 .bdrv_load_vmstate = qcow2_load_vmstate, 4376 4377 .supports_backing = true, 4378 .bdrv_change_backing_file = qcow2_change_backing_file, 4379 4380 .bdrv_refresh_limits = qcow2_refresh_limits, 4381 .bdrv_invalidate_cache = qcow2_invalidate_cache, 4382 .bdrv_inactivate = qcow2_inactivate, 4383 4384 .create_opts = &qcow2_create_opts, 4385 .bdrv_check = qcow2_check, 4386 .bdrv_amend_options = qcow2_amend_options, 4387 4388 .bdrv_detach_aio_context = qcow2_detach_aio_context, 4389 .bdrv_attach_aio_context = qcow2_attach_aio_context, 4390 4391 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 4392 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 4393 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 4394 }; 4395 4396 static void bdrv_qcow2_init(void) 4397 { 4398 bdrv_register(&bdrv_qcow2); 4399 } 4400 4401 block_init(bdrv_qcow2_init); 4402