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/qmp/qerror.h" 34 #include "qapi/qmp/qdict.h" 35 #include "qapi/qmp/qstring.h" 36 #include "qapi-event.h" 37 #include "trace.h" 38 #include "qemu/option_int.h" 39 #include "qemu/cutils.h" 40 #include "qemu/bswap.h" 41 #include "qapi/opts-visitor.h" 42 #include "qapi-visit.h" 43 #include "block/crypto.h" 44 45 /* 46 Differences with QCOW: 47 48 - Support for multiple incremental snapshots. 49 - Memory management by reference counts. 50 - Clusters which have a reference count of one have the bit 51 QCOW_OFLAG_COPIED to optimize write performance. 52 - Size of compressed clusters is stored in sectors to reduce bit usage 53 in the cluster offsets. 54 - Support for storing additional data (such as the VM state) in the 55 snapshots. 56 - If a backing store is used, the cluster size is not constrained 57 (could be backported to QCOW). 58 - L2 tables have always a size of one cluster. 59 */ 60 61 62 typedef struct { 63 uint32_t magic; 64 uint32_t len; 65 } QEMU_PACKED QCowExtension; 66 67 #define QCOW2_EXT_MAGIC_END 0 68 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 69 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 70 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 71 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 72 73 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 74 { 75 const QCowHeader *cow_header = (const void *)buf; 76 77 if (buf_size >= sizeof(QCowHeader) && 78 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 79 be32_to_cpu(cow_header->version) >= 2) 80 return 100; 81 else 82 return 0; 83 } 84 85 86 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 87 uint8_t *buf, size_t buflen, 88 void *opaque, Error **errp) 89 { 90 BlockDriverState *bs = opaque; 91 BDRVQcow2State *s = bs->opaque; 92 ssize_t ret; 93 94 if ((offset + buflen) > s->crypto_header.length) { 95 error_setg(errp, "Request for data outside of extension header"); 96 return -1; 97 } 98 99 ret = bdrv_pread(bs->file, 100 s->crypto_header.offset + offset, buf, buflen); 101 if (ret < 0) { 102 error_setg_errno(errp, -ret, "Could not read encryption header"); 103 return -1; 104 } 105 return ret; 106 } 107 108 109 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 110 void *opaque, Error **errp) 111 { 112 BlockDriverState *bs = opaque; 113 BDRVQcow2State *s = bs->opaque; 114 int64_t ret; 115 int64_t clusterlen; 116 117 ret = qcow2_alloc_clusters(bs, headerlen); 118 if (ret < 0) { 119 error_setg_errno(errp, -ret, 120 "Cannot allocate cluster for LUKS header size %zu", 121 headerlen); 122 return -1; 123 } 124 125 s->crypto_header.length = headerlen; 126 s->crypto_header.offset = ret; 127 128 /* Zero fill remaining space in cluster so it has predictable 129 * content in case of future spec changes */ 130 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 131 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen) == 0); 132 ret = bdrv_pwrite_zeroes(bs->file, 133 ret + headerlen, 134 clusterlen - headerlen, 0); 135 if (ret < 0) { 136 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 137 return -1; 138 } 139 140 return ret; 141 } 142 143 144 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 145 const uint8_t *buf, size_t buflen, 146 void *opaque, Error **errp) 147 { 148 BlockDriverState *bs = opaque; 149 BDRVQcow2State *s = bs->opaque; 150 ssize_t ret; 151 152 if ((offset + buflen) > s->crypto_header.length) { 153 error_setg(errp, "Request for data outside of extension header"); 154 return -1; 155 } 156 157 ret = bdrv_pwrite(bs->file, 158 s->crypto_header.offset + offset, buf, buflen); 159 if (ret < 0) { 160 error_setg_errno(errp, -ret, "Could not read encryption header"); 161 return -1; 162 } 163 return ret; 164 } 165 166 167 /* 168 * read qcow2 extension and fill bs 169 * start reading from start_offset 170 * finish reading upon magic of value 0 or when end_offset reached 171 * unknown magic is skipped (future extension this version knows nothing about) 172 * return 0 upon success, non-0 otherwise 173 */ 174 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 175 uint64_t end_offset, void **p_feature_table, 176 int flags, bool *need_update_header, 177 Error **errp) 178 { 179 BDRVQcow2State *s = bs->opaque; 180 QCowExtension ext; 181 uint64_t offset; 182 int ret; 183 Qcow2BitmapHeaderExt bitmaps_ext; 184 185 if (need_update_header != NULL) { 186 *need_update_header = false; 187 } 188 189 #ifdef DEBUG_EXT 190 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 191 #endif 192 offset = start_offset; 193 while (offset < end_offset) { 194 195 #ifdef DEBUG_EXT 196 /* Sanity check */ 197 if (offset > s->cluster_size) 198 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 199 200 printf("attempting to read extended header in offset %lu\n", offset); 201 #endif 202 203 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 204 if (ret < 0) { 205 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 206 "pread fail from offset %" PRIu64, offset); 207 return 1; 208 } 209 be32_to_cpus(&ext.magic); 210 be32_to_cpus(&ext.len); 211 offset += sizeof(ext); 212 #ifdef DEBUG_EXT 213 printf("ext.magic = 0x%x\n", ext.magic); 214 #endif 215 if (offset > end_offset || ext.len > end_offset - offset) { 216 error_setg(errp, "Header extension too large"); 217 return -EINVAL; 218 } 219 220 switch (ext.magic) { 221 case QCOW2_EXT_MAGIC_END: 222 return 0; 223 224 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 225 if (ext.len >= sizeof(bs->backing_format)) { 226 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 227 " too large (>=%zu)", ext.len, 228 sizeof(bs->backing_format)); 229 return 2; 230 } 231 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 232 if (ret < 0) { 233 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 234 "Could not read format name"); 235 return 3; 236 } 237 bs->backing_format[ext.len] = '\0'; 238 s->image_backing_format = g_strdup(bs->backing_format); 239 #ifdef DEBUG_EXT 240 printf("Qcow2: Got format extension %s\n", bs->backing_format); 241 #endif 242 break; 243 244 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 245 if (p_feature_table != NULL) { 246 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 247 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 248 if (ret < 0) { 249 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 250 "Could not read table"); 251 return ret; 252 } 253 254 *p_feature_table = feature_table; 255 } 256 break; 257 258 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 259 unsigned int cflags = 0; 260 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 261 error_setg(errp, "CRYPTO header extension only " 262 "expected with LUKS encryption method"); 263 return -EINVAL; 264 } 265 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 266 error_setg(errp, "CRYPTO header extension size %u, " 267 "but expected size %zu", ext.len, 268 sizeof(Qcow2CryptoHeaderExtension)); 269 return -EINVAL; 270 } 271 272 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 273 if (ret < 0) { 274 error_setg_errno(errp, -ret, 275 "Unable to read CRYPTO header extension"); 276 return ret; 277 } 278 be64_to_cpus(&s->crypto_header.offset); 279 be64_to_cpus(&s->crypto_header.length); 280 281 if ((s->crypto_header.offset % s->cluster_size) != 0) { 282 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 283 "not a multiple of cluster size '%u'", 284 s->crypto_header.offset, s->cluster_size); 285 return -EINVAL; 286 } 287 288 if (flags & BDRV_O_NO_IO) { 289 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 290 } 291 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 292 qcow2_crypto_hdr_read_func, 293 bs, cflags, errp); 294 if (!s->crypto) { 295 return -EINVAL; 296 } 297 } break; 298 299 case QCOW2_EXT_MAGIC_BITMAPS: 300 if (ext.len != sizeof(bitmaps_ext)) { 301 error_setg_errno(errp, -ret, "bitmaps_ext: " 302 "Invalid extension length"); 303 return -EINVAL; 304 } 305 306 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 307 if (s->qcow_version < 3) { 308 /* Let's be a bit more specific */ 309 warn_report("This qcow2 v2 image contains bitmaps, but " 310 "they may have been modified by a program " 311 "without persistent bitmap support; so now " 312 "they must all be considered inconsistent"); 313 } else { 314 warn_report("a program lacking bitmap support " 315 "modified this file, so all bitmaps are now " 316 "considered inconsistent"); 317 } 318 error_printf("Some clusters may be leaked, " 319 "run 'qemu-img check -r' on the image " 320 "file to fix."); 321 if (need_update_header != NULL) { 322 /* Updating is needed to drop invalid bitmap extension. */ 323 *need_update_header = true; 324 } 325 break; 326 } 327 328 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 329 if (ret < 0) { 330 error_setg_errno(errp, -ret, "bitmaps_ext: " 331 "Could not read ext header"); 332 return ret; 333 } 334 335 if (bitmaps_ext.reserved32 != 0) { 336 error_setg_errno(errp, -ret, "bitmaps_ext: " 337 "Reserved field is not zero"); 338 return -EINVAL; 339 } 340 341 be32_to_cpus(&bitmaps_ext.nb_bitmaps); 342 be64_to_cpus(&bitmaps_ext.bitmap_directory_size); 343 be64_to_cpus(&bitmaps_ext.bitmap_directory_offset); 344 345 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 346 error_setg(errp, 347 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 348 "exceeding the QEMU supported maximum of %d", 349 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 350 return -EINVAL; 351 } 352 353 if (bitmaps_ext.nb_bitmaps == 0) { 354 error_setg(errp, "found bitmaps extension with zero bitmaps"); 355 return -EINVAL; 356 } 357 358 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 359 error_setg(errp, "bitmaps_ext: " 360 "invalid bitmap directory offset"); 361 return -EINVAL; 362 } 363 364 if (bitmaps_ext.bitmap_directory_size > 365 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 366 error_setg(errp, "bitmaps_ext: " 367 "bitmap directory size (%" PRIu64 ") exceeds " 368 "the maximum supported size (%d)", 369 bitmaps_ext.bitmap_directory_size, 370 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 371 return -EINVAL; 372 } 373 374 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 375 s->bitmap_directory_offset = 376 bitmaps_ext.bitmap_directory_offset; 377 s->bitmap_directory_size = 378 bitmaps_ext.bitmap_directory_size; 379 380 #ifdef DEBUG_EXT 381 printf("Qcow2: Got bitmaps extension: " 382 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 383 s->bitmap_directory_offset, s->nb_bitmaps); 384 #endif 385 break; 386 387 default: 388 /* unknown magic - save it in case we need to rewrite the header */ 389 /* If you add a new feature, make sure to also update the fast 390 * path of qcow2_make_empty() to deal with it. */ 391 { 392 Qcow2UnknownHeaderExtension *uext; 393 394 uext = g_malloc0(sizeof(*uext) + ext.len); 395 uext->magic = ext.magic; 396 uext->len = ext.len; 397 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 398 399 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 400 if (ret < 0) { 401 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 402 "Could not read data"); 403 return ret; 404 } 405 } 406 break; 407 } 408 409 offset += ((ext.len + 7) & ~7); 410 } 411 412 return 0; 413 } 414 415 static void cleanup_unknown_header_ext(BlockDriverState *bs) 416 { 417 BDRVQcow2State *s = bs->opaque; 418 Qcow2UnknownHeaderExtension *uext, *next; 419 420 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 421 QLIST_REMOVE(uext, next); 422 g_free(uext); 423 } 424 } 425 426 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 427 uint64_t mask) 428 { 429 char *features = g_strdup(""); 430 char *old; 431 432 while (table && table->name[0] != '\0') { 433 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 434 if (mask & (1ULL << table->bit)) { 435 old = features; 436 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 437 table->name); 438 g_free(old); 439 mask &= ~(1ULL << table->bit); 440 } 441 } 442 table++; 443 } 444 445 if (mask) { 446 old = features; 447 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 448 old, *old ? ", " : "", mask); 449 g_free(old); 450 } 451 452 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 453 g_free(features); 454 } 455 456 /* 457 * Sets the dirty bit and flushes afterwards if necessary. 458 * 459 * The incompatible_features bit is only set if the image file header was 460 * updated successfully. Therefore it is not required to check the return 461 * value of this function. 462 */ 463 int qcow2_mark_dirty(BlockDriverState *bs) 464 { 465 BDRVQcow2State *s = bs->opaque; 466 uint64_t val; 467 int ret; 468 469 assert(s->qcow_version >= 3); 470 471 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 472 return 0; /* already dirty */ 473 } 474 475 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 476 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 477 &val, sizeof(val)); 478 if (ret < 0) { 479 return ret; 480 } 481 ret = bdrv_flush(bs->file->bs); 482 if (ret < 0) { 483 return ret; 484 } 485 486 /* Only treat image as dirty if the header was updated successfully */ 487 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 488 return 0; 489 } 490 491 /* 492 * Clears the dirty bit and flushes before if necessary. Only call this 493 * function when there are no pending requests, it does not guard against 494 * concurrent requests dirtying the image. 495 */ 496 static int qcow2_mark_clean(BlockDriverState *bs) 497 { 498 BDRVQcow2State *s = bs->opaque; 499 500 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 501 int ret; 502 503 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 504 505 ret = bdrv_flush(bs); 506 if (ret < 0) { 507 return ret; 508 } 509 510 return qcow2_update_header(bs); 511 } 512 return 0; 513 } 514 515 /* 516 * Marks the image as corrupt. 517 */ 518 int qcow2_mark_corrupt(BlockDriverState *bs) 519 { 520 BDRVQcow2State *s = bs->opaque; 521 522 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 523 return qcow2_update_header(bs); 524 } 525 526 /* 527 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 528 * before if necessary. 529 */ 530 int qcow2_mark_consistent(BlockDriverState *bs) 531 { 532 BDRVQcow2State *s = bs->opaque; 533 534 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 535 int ret = bdrv_flush(bs); 536 if (ret < 0) { 537 return ret; 538 } 539 540 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 541 return qcow2_update_header(bs); 542 } 543 return 0; 544 } 545 546 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 547 BdrvCheckMode fix) 548 { 549 int ret = qcow2_check_refcounts(bs, result, fix); 550 if (ret < 0) { 551 return ret; 552 } 553 554 if (fix && result->check_errors == 0 && result->corruptions == 0) { 555 ret = qcow2_mark_clean(bs); 556 if (ret < 0) { 557 return ret; 558 } 559 return qcow2_mark_consistent(bs); 560 } 561 return ret; 562 } 563 564 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 565 uint64_t entries, size_t entry_len) 566 { 567 BDRVQcow2State *s = bs->opaque; 568 uint64_t size; 569 570 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 571 * because values will be passed to qemu functions taking int64_t. */ 572 if (entries > INT64_MAX / entry_len) { 573 return -EINVAL; 574 } 575 576 size = entries * entry_len; 577 578 if (INT64_MAX - size < offset) { 579 return -EINVAL; 580 } 581 582 /* Tables must be cluster aligned */ 583 if (offset_into_cluster(s, offset) != 0) { 584 return -EINVAL; 585 } 586 587 return 0; 588 } 589 590 static QemuOptsList qcow2_runtime_opts = { 591 .name = "qcow2", 592 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 593 .desc = { 594 { 595 .name = QCOW2_OPT_LAZY_REFCOUNTS, 596 .type = QEMU_OPT_BOOL, 597 .help = "Postpone refcount updates", 598 }, 599 { 600 .name = QCOW2_OPT_DISCARD_REQUEST, 601 .type = QEMU_OPT_BOOL, 602 .help = "Pass guest discard requests to the layer below", 603 }, 604 { 605 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 606 .type = QEMU_OPT_BOOL, 607 .help = "Generate discard requests when snapshot related space " 608 "is freed", 609 }, 610 { 611 .name = QCOW2_OPT_DISCARD_OTHER, 612 .type = QEMU_OPT_BOOL, 613 .help = "Generate discard requests when other clusters are freed", 614 }, 615 { 616 .name = QCOW2_OPT_OVERLAP, 617 .type = QEMU_OPT_STRING, 618 .help = "Selects which overlap checks to perform from a range of " 619 "templates (none, constant, cached, all)", 620 }, 621 { 622 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 623 .type = QEMU_OPT_STRING, 624 .help = "Selects which overlap checks to perform from a range of " 625 "templates (none, constant, cached, all)", 626 }, 627 { 628 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 629 .type = QEMU_OPT_BOOL, 630 .help = "Check for unintended writes into the main qcow2 header", 631 }, 632 { 633 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 634 .type = QEMU_OPT_BOOL, 635 .help = "Check for unintended writes into the active L1 table", 636 }, 637 { 638 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 639 .type = QEMU_OPT_BOOL, 640 .help = "Check for unintended writes into an active L2 table", 641 }, 642 { 643 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 644 .type = QEMU_OPT_BOOL, 645 .help = "Check for unintended writes into the refcount table", 646 }, 647 { 648 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 649 .type = QEMU_OPT_BOOL, 650 .help = "Check for unintended writes into a refcount block", 651 }, 652 { 653 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 654 .type = QEMU_OPT_BOOL, 655 .help = "Check for unintended writes into the snapshot table", 656 }, 657 { 658 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 659 .type = QEMU_OPT_BOOL, 660 .help = "Check for unintended writes into an inactive L1 table", 661 }, 662 { 663 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 664 .type = QEMU_OPT_BOOL, 665 .help = "Check for unintended writes into an inactive L2 table", 666 }, 667 { 668 .name = QCOW2_OPT_CACHE_SIZE, 669 .type = QEMU_OPT_SIZE, 670 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 671 "cache size", 672 }, 673 { 674 .name = QCOW2_OPT_L2_CACHE_SIZE, 675 .type = QEMU_OPT_SIZE, 676 .help = "Maximum L2 table cache size", 677 }, 678 { 679 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 680 .type = QEMU_OPT_SIZE, 681 .help = "Size of each entry in the L2 cache", 682 }, 683 { 684 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 685 .type = QEMU_OPT_SIZE, 686 .help = "Maximum refcount block cache size", 687 }, 688 { 689 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 690 .type = QEMU_OPT_NUMBER, 691 .help = "Clean unused cache entries after this time (in seconds)", 692 }, 693 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 694 "ID of secret providing qcow2 AES key or LUKS passphrase"), 695 { /* end of list */ } 696 }, 697 }; 698 699 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 700 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 701 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 702 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 703 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 704 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 705 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 706 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 707 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 708 }; 709 710 static void cache_clean_timer_cb(void *opaque) 711 { 712 BlockDriverState *bs = opaque; 713 BDRVQcow2State *s = bs->opaque; 714 qcow2_cache_clean_unused(s->l2_table_cache); 715 qcow2_cache_clean_unused(s->refcount_block_cache); 716 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 717 (int64_t) s->cache_clean_interval * 1000); 718 } 719 720 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 721 { 722 BDRVQcow2State *s = bs->opaque; 723 if (s->cache_clean_interval > 0) { 724 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 725 SCALE_MS, cache_clean_timer_cb, 726 bs); 727 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 728 (int64_t) s->cache_clean_interval * 1000); 729 } 730 } 731 732 static void cache_clean_timer_del(BlockDriverState *bs) 733 { 734 BDRVQcow2State *s = bs->opaque; 735 if (s->cache_clean_timer) { 736 timer_del(s->cache_clean_timer); 737 timer_free(s->cache_clean_timer); 738 s->cache_clean_timer = NULL; 739 } 740 } 741 742 static void qcow2_detach_aio_context(BlockDriverState *bs) 743 { 744 cache_clean_timer_del(bs); 745 } 746 747 static void qcow2_attach_aio_context(BlockDriverState *bs, 748 AioContext *new_context) 749 { 750 cache_clean_timer_init(bs, new_context); 751 } 752 753 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 754 uint64_t *l2_cache_size, 755 uint64_t *l2_cache_entry_size, 756 uint64_t *refcount_cache_size, Error **errp) 757 { 758 BDRVQcow2State *s = bs->opaque; 759 uint64_t combined_cache_size; 760 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 761 762 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 763 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 764 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 765 766 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 767 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 768 *refcount_cache_size = qemu_opt_get_size(opts, 769 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 770 771 *l2_cache_entry_size = qemu_opt_get_size( 772 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 773 774 if (combined_cache_size_set) { 775 if (l2_cache_size_set && refcount_cache_size_set) { 776 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 777 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 778 "the same time"); 779 return; 780 } else if (*l2_cache_size > combined_cache_size) { 781 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 782 QCOW2_OPT_CACHE_SIZE); 783 return; 784 } else if (*refcount_cache_size > combined_cache_size) { 785 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 786 QCOW2_OPT_CACHE_SIZE); 787 return; 788 } 789 790 if (l2_cache_size_set) { 791 *refcount_cache_size = combined_cache_size - *l2_cache_size; 792 } else if (refcount_cache_size_set) { 793 *l2_cache_size = combined_cache_size - *refcount_cache_size; 794 } else { 795 *refcount_cache_size = combined_cache_size 796 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 797 *l2_cache_size = combined_cache_size - *refcount_cache_size; 798 } 799 } else { 800 if (!l2_cache_size_set && !refcount_cache_size_set) { 801 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 802 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 803 * s->cluster_size); 804 *refcount_cache_size = *l2_cache_size 805 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 806 } else if (!l2_cache_size_set) { 807 *l2_cache_size = *refcount_cache_size 808 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 809 } else if (!refcount_cache_size_set) { 810 *refcount_cache_size = *l2_cache_size 811 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 812 } 813 } 814 815 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 816 *l2_cache_entry_size > s->cluster_size || 817 !is_power_of_2(*l2_cache_entry_size)) { 818 error_setg(errp, "L2 cache entry size must be a power of two " 819 "between %d and the cluster size (%d)", 820 1 << MIN_CLUSTER_BITS, s->cluster_size); 821 return; 822 } 823 } 824 825 typedef struct Qcow2ReopenState { 826 Qcow2Cache *l2_table_cache; 827 Qcow2Cache *refcount_block_cache; 828 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 829 bool use_lazy_refcounts; 830 int overlap_check; 831 bool discard_passthrough[QCOW2_DISCARD_MAX]; 832 uint64_t cache_clean_interval; 833 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 834 } Qcow2ReopenState; 835 836 static int qcow2_update_options_prepare(BlockDriverState *bs, 837 Qcow2ReopenState *r, 838 QDict *options, int flags, 839 Error **errp) 840 { 841 BDRVQcow2State *s = bs->opaque; 842 QemuOpts *opts = NULL; 843 const char *opt_overlap_check, *opt_overlap_check_template; 844 int overlap_check_template = 0; 845 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 846 int i; 847 const char *encryptfmt; 848 QDict *encryptopts = NULL; 849 Error *local_err = NULL; 850 int ret; 851 852 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 853 encryptfmt = qdict_get_try_str(encryptopts, "format"); 854 855 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 856 qemu_opts_absorb_qdict(opts, options, &local_err); 857 if (local_err) { 858 error_propagate(errp, local_err); 859 ret = -EINVAL; 860 goto fail; 861 } 862 863 /* get L2 table/refcount block cache size from command line options */ 864 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 865 &refcount_cache_size, &local_err); 866 if (local_err) { 867 error_propagate(errp, local_err); 868 ret = -EINVAL; 869 goto fail; 870 } 871 872 l2_cache_size /= l2_cache_entry_size; 873 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 874 l2_cache_size = MIN_L2_CACHE_SIZE; 875 } 876 if (l2_cache_size > INT_MAX) { 877 error_setg(errp, "L2 cache size too big"); 878 ret = -EINVAL; 879 goto fail; 880 } 881 882 refcount_cache_size /= s->cluster_size; 883 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 884 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 885 } 886 if (refcount_cache_size > INT_MAX) { 887 error_setg(errp, "Refcount cache size too big"); 888 ret = -EINVAL; 889 goto fail; 890 } 891 892 /* alloc new L2 table/refcount block cache, flush old one */ 893 if (s->l2_table_cache) { 894 ret = qcow2_cache_flush(bs, s->l2_table_cache); 895 if (ret) { 896 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 897 goto fail; 898 } 899 } 900 901 if (s->refcount_block_cache) { 902 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 903 if (ret) { 904 error_setg_errno(errp, -ret, 905 "Failed to flush the refcount block cache"); 906 goto fail; 907 } 908 } 909 910 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 911 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 912 l2_cache_entry_size); 913 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 914 s->cluster_size); 915 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 916 error_setg(errp, "Could not allocate metadata caches"); 917 ret = -ENOMEM; 918 goto fail; 919 } 920 921 /* New interval for cache cleanup timer */ 922 r->cache_clean_interval = 923 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 924 s->cache_clean_interval); 925 #ifndef CONFIG_LINUX 926 if (r->cache_clean_interval != 0) { 927 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 928 " not supported on this host"); 929 ret = -EINVAL; 930 goto fail; 931 } 932 #endif 933 if (r->cache_clean_interval > UINT_MAX) { 934 error_setg(errp, "Cache clean interval too big"); 935 ret = -EINVAL; 936 goto fail; 937 } 938 939 /* lazy-refcounts; flush if going from enabled to disabled */ 940 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 941 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 942 if (r->use_lazy_refcounts && s->qcow_version < 3) { 943 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 944 "qemu 1.1 compatibility level"); 945 ret = -EINVAL; 946 goto fail; 947 } 948 949 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 950 ret = qcow2_mark_clean(bs); 951 if (ret < 0) { 952 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 953 goto fail; 954 } 955 } 956 957 /* Overlap check options */ 958 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 959 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 960 if (opt_overlap_check_template && opt_overlap_check && 961 strcmp(opt_overlap_check_template, opt_overlap_check)) 962 { 963 error_setg(errp, "Conflicting values for qcow2 options '" 964 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 965 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 966 ret = -EINVAL; 967 goto fail; 968 } 969 if (!opt_overlap_check) { 970 opt_overlap_check = opt_overlap_check_template ?: "cached"; 971 } 972 973 if (!strcmp(opt_overlap_check, "none")) { 974 overlap_check_template = 0; 975 } else if (!strcmp(opt_overlap_check, "constant")) { 976 overlap_check_template = QCOW2_OL_CONSTANT; 977 } else if (!strcmp(opt_overlap_check, "cached")) { 978 overlap_check_template = QCOW2_OL_CACHED; 979 } else if (!strcmp(opt_overlap_check, "all")) { 980 overlap_check_template = QCOW2_OL_ALL; 981 } else { 982 error_setg(errp, "Unsupported value '%s' for qcow2 option " 983 "'overlap-check'. Allowed are any of the following: " 984 "none, constant, cached, all", opt_overlap_check); 985 ret = -EINVAL; 986 goto fail; 987 } 988 989 r->overlap_check = 0; 990 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 991 /* overlap-check defines a template bitmask, but every flag may be 992 * overwritten through the associated boolean option */ 993 r->overlap_check |= 994 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 995 overlap_check_template & (1 << i)) << i; 996 } 997 998 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 999 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1000 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1001 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1002 flags & BDRV_O_UNMAP); 1003 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1004 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1005 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1006 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1007 1008 switch (s->crypt_method_header) { 1009 case QCOW_CRYPT_NONE: 1010 if (encryptfmt) { 1011 error_setg(errp, "No encryption in image header, but options " 1012 "specified format '%s'", encryptfmt); 1013 ret = -EINVAL; 1014 goto fail; 1015 } 1016 break; 1017 1018 case QCOW_CRYPT_AES: 1019 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1020 error_setg(errp, 1021 "Header reported 'aes' encryption format but " 1022 "options specify '%s'", encryptfmt); 1023 ret = -EINVAL; 1024 goto fail; 1025 } 1026 qdict_del(encryptopts, "format"); 1027 r->crypto_opts = block_crypto_open_opts_init( 1028 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 1029 break; 1030 1031 case QCOW_CRYPT_LUKS: 1032 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1033 error_setg(errp, 1034 "Header reported 'luks' encryption format but " 1035 "options specify '%s'", encryptfmt); 1036 ret = -EINVAL; 1037 goto fail; 1038 } 1039 qdict_del(encryptopts, "format"); 1040 r->crypto_opts = block_crypto_open_opts_init( 1041 Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); 1042 break; 1043 1044 default: 1045 error_setg(errp, "Unsupported encryption method %d", 1046 s->crypt_method_header); 1047 break; 1048 } 1049 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1050 ret = -EINVAL; 1051 goto fail; 1052 } 1053 1054 ret = 0; 1055 fail: 1056 QDECREF(encryptopts); 1057 qemu_opts_del(opts); 1058 opts = NULL; 1059 return ret; 1060 } 1061 1062 static void qcow2_update_options_commit(BlockDriverState *bs, 1063 Qcow2ReopenState *r) 1064 { 1065 BDRVQcow2State *s = bs->opaque; 1066 int i; 1067 1068 if (s->l2_table_cache) { 1069 qcow2_cache_destroy(s->l2_table_cache); 1070 } 1071 if (s->refcount_block_cache) { 1072 qcow2_cache_destroy(s->refcount_block_cache); 1073 } 1074 s->l2_table_cache = r->l2_table_cache; 1075 s->refcount_block_cache = r->refcount_block_cache; 1076 s->l2_slice_size = r->l2_slice_size; 1077 1078 s->overlap_check = r->overlap_check; 1079 s->use_lazy_refcounts = r->use_lazy_refcounts; 1080 1081 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1082 s->discard_passthrough[i] = r->discard_passthrough[i]; 1083 } 1084 1085 if (s->cache_clean_interval != r->cache_clean_interval) { 1086 cache_clean_timer_del(bs); 1087 s->cache_clean_interval = r->cache_clean_interval; 1088 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1089 } 1090 1091 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1092 s->crypto_opts = r->crypto_opts; 1093 } 1094 1095 static void qcow2_update_options_abort(BlockDriverState *bs, 1096 Qcow2ReopenState *r) 1097 { 1098 if (r->l2_table_cache) { 1099 qcow2_cache_destroy(r->l2_table_cache); 1100 } 1101 if (r->refcount_block_cache) { 1102 qcow2_cache_destroy(r->refcount_block_cache); 1103 } 1104 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1105 } 1106 1107 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1108 int flags, Error **errp) 1109 { 1110 Qcow2ReopenState r = {}; 1111 int ret; 1112 1113 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1114 if (ret >= 0) { 1115 qcow2_update_options_commit(bs, &r); 1116 } else { 1117 qcow2_update_options_abort(bs, &r); 1118 } 1119 1120 return ret; 1121 } 1122 1123 static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, 1124 Error **errp) 1125 { 1126 BDRVQcow2State *s = bs->opaque; 1127 unsigned int len, i; 1128 int ret = 0; 1129 QCowHeader header; 1130 Error *local_err = NULL; 1131 uint64_t ext_end; 1132 uint64_t l1_vm_state_index; 1133 bool update_header = false; 1134 1135 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1136 if (ret < 0) { 1137 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1138 goto fail; 1139 } 1140 be32_to_cpus(&header.magic); 1141 be32_to_cpus(&header.version); 1142 be64_to_cpus(&header.backing_file_offset); 1143 be32_to_cpus(&header.backing_file_size); 1144 be64_to_cpus(&header.size); 1145 be32_to_cpus(&header.cluster_bits); 1146 be32_to_cpus(&header.crypt_method); 1147 be64_to_cpus(&header.l1_table_offset); 1148 be32_to_cpus(&header.l1_size); 1149 be64_to_cpus(&header.refcount_table_offset); 1150 be32_to_cpus(&header.refcount_table_clusters); 1151 be64_to_cpus(&header.snapshots_offset); 1152 be32_to_cpus(&header.nb_snapshots); 1153 1154 if (header.magic != QCOW_MAGIC) { 1155 error_setg(errp, "Image is not in qcow2 format"); 1156 ret = -EINVAL; 1157 goto fail; 1158 } 1159 if (header.version < 2 || header.version > 3) { 1160 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1161 ret = -ENOTSUP; 1162 goto fail; 1163 } 1164 1165 s->qcow_version = header.version; 1166 1167 /* Initialise cluster size */ 1168 if (header.cluster_bits < MIN_CLUSTER_BITS || 1169 header.cluster_bits > MAX_CLUSTER_BITS) { 1170 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1171 header.cluster_bits); 1172 ret = -EINVAL; 1173 goto fail; 1174 } 1175 1176 s->cluster_bits = header.cluster_bits; 1177 s->cluster_size = 1 << s->cluster_bits; 1178 s->cluster_sectors = 1 << (s->cluster_bits - BDRV_SECTOR_BITS); 1179 1180 /* Initialise version 3 header fields */ 1181 if (header.version == 2) { 1182 header.incompatible_features = 0; 1183 header.compatible_features = 0; 1184 header.autoclear_features = 0; 1185 header.refcount_order = 4; 1186 header.header_length = 72; 1187 } else { 1188 be64_to_cpus(&header.incompatible_features); 1189 be64_to_cpus(&header.compatible_features); 1190 be64_to_cpus(&header.autoclear_features); 1191 be32_to_cpus(&header.refcount_order); 1192 be32_to_cpus(&header.header_length); 1193 1194 if (header.header_length < 104) { 1195 error_setg(errp, "qcow2 header too short"); 1196 ret = -EINVAL; 1197 goto fail; 1198 } 1199 } 1200 1201 if (header.header_length > s->cluster_size) { 1202 error_setg(errp, "qcow2 header exceeds cluster size"); 1203 ret = -EINVAL; 1204 goto fail; 1205 } 1206 1207 if (header.header_length > sizeof(header)) { 1208 s->unknown_header_fields_size = header.header_length - sizeof(header); 1209 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1210 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1211 s->unknown_header_fields_size); 1212 if (ret < 0) { 1213 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1214 "fields"); 1215 goto fail; 1216 } 1217 } 1218 1219 if (header.backing_file_offset > s->cluster_size) { 1220 error_setg(errp, "Invalid backing file offset"); 1221 ret = -EINVAL; 1222 goto fail; 1223 } 1224 1225 if (header.backing_file_offset) { 1226 ext_end = header.backing_file_offset; 1227 } else { 1228 ext_end = 1 << header.cluster_bits; 1229 } 1230 1231 /* Handle feature bits */ 1232 s->incompatible_features = header.incompatible_features; 1233 s->compatible_features = header.compatible_features; 1234 s->autoclear_features = header.autoclear_features; 1235 1236 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1237 void *feature_table = NULL; 1238 qcow2_read_extensions(bs, header.header_length, ext_end, 1239 &feature_table, flags, NULL, NULL); 1240 report_unsupported_feature(errp, feature_table, 1241 s->incompatible_features & 1242 ~QCOW2_INCOMPAT_MASK); 1243 ret = -ENOTSUP; 1244 g_free(feature_table); 1245 goto fail; 1246 } 1247 1248 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1249 /* Corrupt images may not be written to unless they are being repaired 1250 */ 1251 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1252 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1253 "read/write"); 1254 ret = -EACCES; 1255 goto fail; 1256 } 1257 } 1258 1259 /* Check support for various header values */ 1260 if (header.refcount_order > 6) { 1261 error_setg(errp, "Reference count entry width too large; may not " 1262 "exceed 64 bits"); 1263 ret = -EINVAL; 1264 goto fail; 1265 } 1266 s->refcount_order = header.refcount_order; 1267 s->refcount_bits = 1 << s->refcount_order; 1268 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1269 s->refcount_max += s->refcount_max - 1; 1270 1271 s->crypt_method_header = header.crypt_method; 1272 if (s->crypt_method_header) { 1273 if (bdrv_uses_whitelist() && 1274 s->crypt_method_header == QCOW_CRYPT_AES) { 1275 error_setg(errp, 1276 "Use of AES-CBC encrypted qcow2 images is no longer " 1277 "supported in system emulators"); 1278 error_append_hint(errp, 1279 "You can use 'qemu-img convert' to convert your " 1280 "image to an alternative supported format, such " 1281 "as unencrypted qcow2, or raw with the LUKS " 1282 "format instead.\n"); 1283 ret = -ENOSYS; 1284 goto fail; 1285 } 1286 1287 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1288 s->crypt_physical_offset = false; 1289 } else { 1290 /* Assuming LUKS and any future crypt methods we 1291 * add will all use physical offsets, due to the 1292 * fact that the alternative is insecure... */ 1293 s->crypt_physical_offset = true; 1294 } 1295 1296 bs->encrypted = true; 1297 } 1298 1299 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1300 s->l2_size = 1 << s->l2_bits; 1301 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1302 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1303 s->refcount_block_size = 1 << s->refcount_block_bits; 1304 bs->total_sectors = header.size / 512; 1305 s->csize_shift = (62 - (s->cluster_bits - 8)); 1306 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1307 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1308 1309 s->refcount_table_offset = header.refcount_table_offset; 1310 s->refcount_table_size = 1311 header.refcount_table_clusters << (s->cluster_bits - 3); 1312 1313 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 1314 error_setg(errp, "Reference count table too large"); 1315 ret = -EINVAL; 1316 goto fail; 1317 } 1318 1319 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1320 error_setg(errp, "Image does not contain a reference count table"); 1321 ret = -EINVAL; 1322 goto fail; 1323 } 1324 1325 ret = validate_table_offset(bs, s->refcount_table_offset, 1326 s->refcount_table_size, sizeof(uint64_t)); 1327 if (ret < 0) { 1328 error_setg(errp, "Invalid reference count table offset"); 1329 goto fail; 1330 } 1331 1332 /* Snapshot table offset/length */ 1333 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1334 error_setg(errp, "Too many snapshots"); 1335 ret = -EINVAL; 1336 goto fail; 1337 } 1338 1339 ret = validate_table_offset(bs, header.snapshots_offset, 1340 header.nb_snapshots, 1341 sizeof(QCowSnapshotHeader)); 1342 if (ret < 0) { 1343 error_setg(errp, "Invalid snapshot table offset"); 1344 goto fail; 1345 } 1346 1347 /* read the level 1 table */ 1348 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1349 error_setg(errp, "Active L1 table too large"); 1350 ret = -EFBIG; 1351 goto fail; 1352 } 1353 s->l1_size = header.l1_size; 1354 1355 l1_vm_state_index = size_to_l1(s, header.size); 1356 if (l1_vm_state_index > INT_MAX) { 1357 error_setg(errp, "Image is too big"); 1358 ret = -EFBIG; 1359 goto fail; 1360 } 1361 s->l1_vm_state_index = l1_vm_state_index; 1362 1363 /* the L1 table must contain at least enough entries to put 1364 header.size bytes */ 1365 if (s->l1_size < s->l1_vm_state_index) { 1366 error_setg(errp, "L1 table is too small"); 1367 ret = -EINVAL; 1368 goto fail; 1369 } 1370 1371 ret = validate_table_offset(bs, header.l1_table_offset, 1372 header.l1_size, sizeof(uint64_t)); 1373 if (ret < 0) { 1374 error_setg(errp, "Invalid L1 table offset"); 1375 goto fail; 1376 } 1377 s->l1_table_offset = header.l1_table_offset; 1378 1379 1380 if (s->l1_size > 0) { 1381 s->l1_table = qemu_try_blockalign(bs->file->bs, 1382 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1383 if (s->l1_table == NULL) { 1384 error_setg(errp, "Could not allocate L1 table"); 1385 ret = -ENOMEM; 1386 goto fail; 1387 } 1388 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1389 s->l1_size * sizeof(uint64_t)); 1390 if (ret < 0) { 1391 error_setg_errno(errp, -ret, "Could not read L1 table"); 1392 goto fail; 1393 } 1394 for(i = 0;i < s->l1_size; i++) { 1395 be64_to_cpus(&s->l1_table[i]); 1396 } 1397 } 1398 1399 /* Parse driver-specific options */ 1400 ret = qcow2_update_options(bs, options, flags, errp); 1401 if (ret < 0) { 1402 goto fail; 1403 } 1404 1405 s->cluster_cache_offset = -1; 1406 s->flags = flags; 1407 1408 ret = qcow2_refcount_init(bs); 1409 if (ret != 0) { 1410 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1411 goto fail; 1412 } 1413 1414 QLIST_INIT(&s->cluster_allocs); 1415 QTAILQ_INIT(&s->discards); 1416 1417 /* read qcow2 extensions */ 1418 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1419 flags, &update_header, &local_err)) { 1420 error_propagate(errp, local_err); 1421 ret = -EINVAL; 1422 goto fail; 1423 } 1424 1425 /* qcow2_read_extension may have set up the crypto context 1426 * if the crypt method needs a header region, some methods 1427 * don't need header extensions, so must check here 1428 */ 1429 if (s->crypt_method_header && !s->crypto) { 1430 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1431 unsigned int cflags = 0; 1432 if (flags & BDRV_O_NO_IO) { 1433 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1434 } 1435 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1436 NULL, NULL, cflags, errp); 1437 if (!s->crypto) { 1438 ret = -EINVAL; 1439 goto fail; 1440 } 1441 } else if (!(flags & BDRV_O_NO_IO)) { 1442 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1443 s->crypt_method_header); 1444 ret = -EINVAL; 1445 goto fail; 1446 } 1447 } 1448 1449 /* read the backing file name */ 1450 if (header.backing_file_offset != 0) { 1451 len = header.backing_file_size; 1452 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1453 len >= sizeof(bs->backing_file)) { 1454 error_setg(errp, "Backing file name too long"); 1455 ret = -EINVAL; 1456 goto fail; 1457 } 1458 ret = bdrv_pread(bs->file, header.backing_file_offset, 1459 bs->backing_file, len); 1460 if (ret < 0) { 1461 error_setg_errno(errp, -ret, "Could not read backing file name"); 1462 goto fail; 1463 } 1464 bs->backing_file[len] = '\0'; 1465 s->image_backing_file = g_strdup(bs->backing_file); 1466 } 1467 1468 /* Internal snapshots */ 1469 s->snapshots_offset = header.snapshots_offset; 1470 s->nb_snapshots = header.nb_snapshots; 1471 1472 ret = qcow2_read_snapshots(bs); 1473 if (ret < 0) { 1474 error_setg_errno(errp, -ret, "Could not read snapshots"); 1475 goto fail; 1476 } 1477 1478 /* Clear unknown autoclear feature bits */ 1479 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1480 update_header = 1481 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1482 if (update_header) { 1483 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1484 } 1485 1486 if (qcow2_load_dirty_bitmaps(bs, &local_err)) { 1487 update_header = false; 1488 } 1489 if (local_err != NULL) { 1490 error_propagate(errp, local_err); 1491 ret = -EINVAL; 1492 goto fail; 1493 } 1494 1495 if (update_header) { 1496 ret = qcow2_update_header(bs); 1497 if (ret < 0) { 1498 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1499 goto fail; 1500 } 1501 } 1502 1503 /* Initialise locks */ 1504 qemu_co_mutex_init(&s->lock); 1505 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1506 1507 /* Repair image if dirty */ 1508 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1509 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1510 BdrvCheckResult result = {0}; 1511 1512 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1513 if (ret < 0 || result.check_errors) { 1514 if (ret >= 0) { 1515 ret = -EIO; 1516 } 1517 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1518 goto fail; 1519 } 1520 } 1521 1522 #ifdef DEBUG_ALLOC 1523 { 1524 BdrvCheckResult result = {0}; 1525 qcow2_check_refcounts(bs, &result, 0); 1526 } 1527 #endif 1528 return ret; 1529 1530 fail: 1531 g_free(s->unknown_header_fields); 1532 cleanup_unknown_header_ext(bs); 1533 qcow2_free_snapshots(bs); 1534 qcow2_refcount_close(bs); 1535 qemu_vfree(s->l1_table); 1536 /* else pre-write overlap checks in cache_destroy may crash */ 1537 s->l1_table = NULL; 1538 cache_clean_timer_del(bs); 1539 if (s->l2_table_cache) { 1540 qcow2_cache_destroy(s->l2_table_cache); 1541 } 1542 if (s->refcount_block_cache) { 1543 qcow2_cache_destroy(s->refcount_block_cache); 1544 } 1545 qcrypto_block_free(s->crypto); 1546 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1547 return ret; 1548 } 1549 1550 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1551 Error **errp) 1552 { 1553 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1554 false, errp); 1555 if (!bs->file) { 1556 return -EINVAL; 1557 } 1558 1559 return qcow2_do_open(bs, options, flags, errp); 1560 } 1561 1562 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1563 { 1564 BDRVQcow2State *s = bs->opaque; 1565 1566 if (bs->encrypted) { 1567 /* Encryption works on a sector granularity */ 1568 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 1569 } 1570 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1571 bs->bl.pdiscard_alignment = s->cluster_size; 1572 } 1573 1574 static int qcow2_reopen_prepare(BDRVReopenState *state, 1575 BlockReopenQueue *queue, Error **errp) 1576 { 1577 Qcow2ReopenState *r; 1578 int ret; 1579 1580 r = g_new0(Qcow2ReopenState, 1); 1581 state->opaque = r; 1582 1583 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1584 state->flags, errp); 1585 if (ret < 0) { 1586 goto fail; 1587 } 1588 1589 /* We need to write out any unwritten data if we reopen read-only. */ 1590 if ((state->flags & BDRV_O_RDWR) == 0) { 1591 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1592 if (ret < 0) { 1593 goto fail; 1594 } 1595 1596 ret = bdrv_flush(state->bs); 1597 if (ret < 0) { 1598 goto fail; 1599 } 1600 1601 ret = qcow2_mark_clean(state->bs); 1602 if (ret < 0) { 1603 goto fail; 1604 } 1605 } 1606 1607 return 0; 1608 1609 fail: 1610 qcow2_update_options_abort(state->bs, r); 1611 g_free(r); 1612 return ret; 1613 } 1614 1615 static void qcow2_reopen_commit(BDRVReopenState *state) 1616 { 1617 qcow2_update_options_commit(state->bs, state->opaque); 1618 g_free(state->opaque); 1619 } 1620 1621 static void qcow2_reopen_abort(BDRVReopenState *state) 1622 { 1623 qcow2_update_options_abort(state->bs, state->opaque); 1624 g_free(state->opaque); 1625 } 1626 1627 static void qcow2_join_options(QDict *options, QDict *old_options) 1628 { 1629 bool has_new_overlap_template = 1630 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1631 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1632 bool has_new_total_cache_size = 1633 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1634 bool has_all_cache_options; 1635 1636 /* New overlap template overrides all old overlap options */ 1637 if (has_new_overlap_template) { 1638 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1639 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1640 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1641 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1642 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1643 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1644 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1645 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1646 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1647 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1648 } 1649 1650 /* New total cache size overrides all old options */ 1651 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1652 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1653 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1654 } 1655 1656 qdict_join(options, old_options, false); 1657 1658 /* 1659 * If after merging all cache size options are set, an old total size is 1660 * overwritten. Do keep all options, however, if all three are new. The 1661 * resulting error message is what we want to happen. 1662 */ 1663 has_all_cache_options = 1664 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1665 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1666 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1667 1668 if (has_all_cache_options && !has_new_total_cache_size) { 1669 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1670 } 1671 } 1672 1673 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1674 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1675 { 1676 BDRVQcow2State *s = bs->opaque; 1677 uint64_t cluster_offset; 1678 int index_in_cluster, ret; 1679 unsigned int bytes; 1680 int64_t status = 0; 1681 1682 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE); 1683 qemu_co_mutex_lock(&s->lock); 1684 ret = qcow2_get_cluster_offset(bs, sector_num << BDRV_SECTOR_BITS, &bytes, 1685 &cluster_offset); 1686 qemu_co_mutex_unlock(&s->lock); 1687 if (ret < 0) { 1688 return ret; 1689 } 1690 1691 *pnum = bytes >> BDRV_SECTOR_BITS; 1692 1693 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1694 !s->crypto) { 1695 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1696 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1697 *file = bs->file->bs; 1698 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1699 } 1700 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1701 status |= BDRV_BLOCK_ZERO; 1702 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1703 status |= BDRV_BLOCK_DATA; 1704 } 1705 return status; 1706 } 1707 1708 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1709 uint64_t bytes, QEMUIOVector *qiov, 1710 int flags) 1711 { 1712 BDRVQcow2State *s = bs->opaque; 1713 int offset_in_cluster; 1714 int ret; 1715 unsigned int cur_bytes; /* number of bytes in current iteration */ 1716 uint64_t cluster_offset = 0; 1717 uint64_t bytes_done = 0; 1718 QEMUIOVector hd_qiov; 1719 uint8_t *cluster_data = NULL; 1720 1721 qemu_iovec_init(&hd_qiov, qiov->niov); 1722 1723 qemu_co_mutex_lock(&s->lock); 1724 1725 while (bytes != 0) { 1726 1727 /* prepare next request */ 1728 cur_bytes = MIN(bytes, INT_MAX); 1729 if (s->crypto) { 1730 cur_bytes = MIN(cur_bytes, 1731 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1732 } 1733 1734 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1735 if (ret < 0) { 1736 goto fail; 1737 } 1738 1739 offset_in_cluster = offset_into_cluster(s, offset); 1740 1741 qemu_iovec_reset(&hd_qiov); 1742 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1743 1744 switch (ret) { 1745 case QCOW2_CLUSTER_UNALLOCATED: 1746 1747 if (bs->backing) { 1748 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1749 qemu_co_mutex_unlock(&s->lock); 1750 ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, 1751 &hd_qiov, 0); 1752 qemu_co_mutex_lock(&s->lock); 1753 if (ret < 0) { 1754 goto fail; 1755 } 1756 } else { 1757 /* Note: in this case, no need to wait */ 1758 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1759 } 1760 break; 1761 1762 case QCOW2_CLUSTER_ZERO_PLAIN: 1763 case QCOW2_CLUSTER_ZERO_ALLOC: 1764 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1765 break; 1766 1767 case QCOW2_CLUSTER_COMPRESSED: 1768 /* add AIO support for compressed blocks ? */ 1769 ret = qcow2_decompress_cluster(bs, cluster_offset); 1770 if (ret < 0) { 1771 goto fail; 1772 } 1773 1774 qemu_iovec_from_buf(&hd_qiov, 0, 1775 s->cluster_cache + offset_in_cluster, 1776 cur_bytes); 1777 break; 1778 1779 case QCOW2_CLUSTER_NORMAL: 1780 if ((cluster_offset & 511) != 0) { 1781 ret = -EIO; 1782 goto fail; 1783 } 1784 1785 if (bs->encrypted) { 1786 assert(s->crypto); 1787 1788 /* 1789 * For encrypted images, read everything into a temporary 1790 * contiguous buffer on which the AES functions can work. 1791 */ 1792 if (!cluster_data) { 1793 cluster_data = 1794 qemu_try_blockalign(bs->file->bs, 1795 QCOW_MAX_CRYPT_CLUSTERS 1796 * s->cluster_size); 1797 if (cluster_data == NULL) { 1798 ret = -ENOMEM; 1799 goto fail; 1800 } 1801 } 1802 1803 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1804 qemu_iovec_reset(&hd_qiov); 1805 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1806 } 1807 1808 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1809 qemu_co_mutex_unlock(&s->lock); 1810 ret = bdrv_co_preadv(bs->file, 1811 cluster_offset + offset_in_cluster, 1812 cur_bytes, &hd_qiov, 0); 1813 qemu_co_mutex_lock(&s->lock); 1814 if (ret < 0) { 1815 goto fail; 1816 } 1817 if (bs->encrypted) { 1818 assert(s->crypto); 1819 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1820 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1821 if (qcrypto_block_decrypt(s->crypto, 1822 (s->crypt_physical_offset ? 1823 cluster_offset + offset_in_cluster : 1824 offset), 1825 cluster_data, 1826 cur_bytes, 1827 NULL) < 0) { 1828 ret = -EIO; 1829 goto fail; 1830 } 1831 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1832 } 1833 break; 1834 1835 default: 1836 g_assert_not_reached(); 1837 ret = -EIO; 1838 goto fail; 1839 } 1840 1841 bytes -= cur_bytes; 1842 offset += cur_bytes; 1843 bytes_done += cur_bytes; 1844 } 1845 ret = 0; 1846 1847 fail: 1848 qemu_co_mutex_unlock(&s->lock); 1849 1850 qemu_iovec_destroy(&hd_qiov); 1851 qemu_vfree(cluster_data); 1852 1853 return ret; 1854 } 1855 1856 /* Check if it's possible to merge a write request with the writing of 1857 * the data from the COW regions */ 1858 static bool merge_cow(uint64_t offset, unsigned bytes, 1859 QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) 1860 { 1861 QCowL2Meta *m; 1862 1863 for (m = l2meta; m != NULL; m = m->next) { 1864 /* If both COW regions are empty then there's nothing to merge */ 1865 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 1866 continue; 1867 } 1868 1869 /* The data (middle) region must be immediately after the 1870 * start region */ 1871 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 1872 continue; 1873 } 1874 1875 /* The end region must be immediately after the data (middle) 1876 * region */ 1877 if (m->offset + m->cow_end.offset != offset + bytes) { 1878 continue; 1879 } 1880 1881 /* Make sure that adding both COW regions to the QEMUIOVector 1882 * does not exceed IOV_MAX */ 1883 if (hd_qiov->niov > IOV_MAX - 2) { 1884 continue; 1885 } 1886 1887 m->data_qiov = hd_qiov; 1888 return true; 1889 } 1890 1891 return false; 1892 } 1893 1894 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 1895 uint64_t bytes, QEMUIOVector *qiov, 1896 int flags) 1897 { 1898 BDRVQcow2State *s = bs->opaque; 1899 int offset_in_cluster; 1900 int ret; 1901 unsigned int cur_bytes; /* number of sectors in current iteration */ 1902 uint64_t cluster_offset; 1903 QEMUIOVector hd_qiov; 1904 uint64_t bytes_done = 0; 1905 uint8_t *cluster_data = NULL; 1906 QCowL2Meta *l2meta = NULL; 1907 1908 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 1909 1910 qemu_iovec_init(&hd_qiov, qiov->niov); 1911 1912 s->cluster_cache_offset = -1; /* disable compressed cache */ 1913 1914 qemu_co_mutex_lock(&s->lock); 1915 1916 while (bytes != 0) { 1917 1918 l2meta = NULL; 1919 1920 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1921 offset_in_cluster = offset_into_cluster(s, offset); 1922 cur_bytes = MIN(bytes, INT_MAX); 1923 if (bs->encrypted) { 1924 cur_bytes = MIN(cur_bytes, 1925 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 1926 - offset_in_cluster); 1927 } 1928 1929 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 1930 &cluster_offset, &l2meta); 1931 if (ret < 0) { 1932 goto fail; 1933 } 1934 1935 assert((cluster_offset & 511) == 0); 1936 1937 qemu_iovec_reset(&hd_qiov); 1938 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1939 1940 if (bs->encrypted) { 1941 assert(s->crypto); 1942 if (!cluster_data) { 1943 cluster_data = qemu_try_blockalign(bs->file->bs, 1944 QCOW_MAX_CRYPT_CLUSTERS 1945 * s->cluster_size); 1946 if (cluster_data == NULL) { 1947 ret = -ENOMEM; 1948 goto fail; 1949 } 1950 } 1951 1952 assert(hd_qiov.size <= 1953 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1954 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1955 1956 if (qcrypto_block_encrypt(s->crypto, 1957 (s->crypt_physical_offset ? 1958 cluster_offset + offset_in_cluster : 1959 offset), 1960 cluster_data, 1961 cur_bytes, NULL) < 0) { 1962 ret = -EIO; 1963 goto fail; 1964 } 1965 1966 qemu_iovec_reset(&hd_qiov); 1967 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1968 } 1969 1970 ret = qcow2_pre_write_overlap_check(bs, 0, 1971 cluster_offset + offset_in_cluster, cur_bytes); 1972 if (ret < 0) { 1973 goto fail; 1974 } 1975 1976 /* If we need to do COW, check if it's possible to merge the 1977 * writing of the guest data together with that of the COW regions. 1978 * If it's not possible (or not necessary) then write the 1979 * guest data now. */ 1980 if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { 1981 qemu_co_mutex_unlock(&s->lock); 1982 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1983 trace_qcow2_writev_data(qemu_coroutine_self(), 1984 cluster_offset + offset_in_cluster); 1985 ret = bdrv_co_pwritev(bs->file, 1986 cluster_offset + offset_in_cluster, 1987 cur_bytes, &hd_qiov, 0); 1988 qemu_co_mutex_lock(&s->lock); 1989 if (ret < 0) { 1990 goto fail; 1991 } 1992 } 1993 1994 while (l2meta != NULL) { 1995 QCowL2Meta *next; 1996 1997 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1998 if (ret < 0) { 1999 goto fail; 2000 } 2001 2002 /* Take the request off the list of running requests */ 2003 if (l2meta->nb_clusters != 0) { 2004 QLIST_REMOVE(l2meta, next_in_flight); 2005 } 2006 2007 qemu_co_queue_restart_all(&l2meta->dependent_requests); 2008 2009 next = l2meta->next; 2010 g_free(l2meta); 2011 l2meta = next; 2012 } 2013 2014 bytes -= cur_bytes; 2015 offset += cur_bytes; 2016 bytes_done += cur_bytes; 2017 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2018 } 2019 ret = 0; 2020 2021 fail: 2022 while (l2meta != NULL) { 2023 QCowL2Meta *next; 2024 2025 if (l2meta->nb_clusters != 0) { 2026 QLIST_REMOVE(l2meta, next_in_flight); 2027 } 2028 qemu_co_queue_restart_all(&l2meta->dependent_requests); 2029 2030 next = l2meta->next; 2031 g_free(l2meta); 2032 l2meta = next; 2033 } 2034 2035 qemu_co_mutex_unlock(&s->lock); 2036 2037 qemu_iovec_destroy(&hd_qiov); 2038 qemu_vfree(cluster_data); 2039 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2040 2041 return ret; 2042 } 2043 2044 static int qcow2_inactivate(BlockDriverState *bs) 2045 { 2046 BDRVQcow2State *s = bs->opaque; 2047 int ret, result = 0; 2048 Error *local_err = NULL; 2049 2050 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2051 if (local_err != NULL) { 2052 result = -EINVAL; 2053 error_report_err(local_err); 2054 error_report("Persistent bitmaps are lost for node '%s'", 2055 bdrv_get_device_or_node_name(bs)); 2056 } 2057 2058 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2059 if (ret) { 2060 result = ret; 2061 error_report("Failed to flush the L2 table cache: %s", 2062 strerror(-ret)); 2063 } 2064 2065 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2066 if (ret) { 2067 result = ret; 2068 error_report("Failed to flush the refcount block cache: %s", 2069 strerror(-ret)); 2070 } 2071 2072 if (result == 0) { 2073 qcow2_mark_clean(bs); 2074 } 2075 2076 return result; 2077 } 2078 2079 static void qcow2_close(BlockDriverState *bs) 2080 { 2081 BDRVQcow2State *s = bs->opaque; 2082 qemu_vfree(s->l1_table); 2083 /* else pre-write overlap checks in cache_destroy may crash */ 2084 s->l1_table = NULL; 2085 2086 if (!(s->flags & BDRV_O_INACTIVE)) { 2087 qcow2_inactivate(bs); 2088 } 2089 2090 cache_clean_timer_del(bs); 2091 qcow2_cache_destroy(s->l2_table_cache); 2092 qcow2_cache_destroy(s->refcount_block_cache); 2093 2094 qcrypto_block_free(s->crypto); 2095 s->crypto = NULL; 2096 2097 g_free(s->unknown_header_fields); 2098 cleanup_unknown_header_ext(bs); 2099 2100 g_free(s->image_backing_file); 2101 g_free(s->image_backing_format); 2102 2103 g_free(s->cluster_cache); 2104 qemu_vfree(s->cluster_data); 2105 qcow2_refcount_close(bs); 2106 qcow2_free_snapshots(bs); 2107 } 2108 2109 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 2110 { 2111 BDRVQcow2State *s = bs->opaque; 2112 int flags = s->flags; 2113 QCryptoBlock *crypto = NULL; 2114 QDict *options; 2115 Error *local_err = NULL; 2116 int ret; 2117 2118 /* 2119 * Backing files are read-only which makes all of their metadata immutable, 2120 * that means we don't have to worry about reopening them here. 2121 */ 2122 2123 crypto = s->crypto; 2124 s->crypto = NULL; 2125 2126 qcow2_close(bs); 2127 2128 memset(s, 0, sizeof(BDRVQcow2State)); 2129 options = qdict_clone_shallow(bs->options); 2130 2131 flags &= ~BDRV_O_INACTIVE; 2132 ret = qcow2_do_open(bs, options, flags, &local_err); 2133 QDECREF(options); 2134 if (local_err) { 2135 error_propagate(errp, local_err); 2136 error_prepend(errp, "Could not reopen qcow2 layer: "); 2137 bs->drv = NULL; 2138 return; 2139 } else if (ret < 0) { 2140 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2141 bs->drv = NULL; 2142 return; 2143 } 2144 2145 s->crypto = crypto; 2146 } 2147 2148 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2149 size_t len, size_t buflen) 2150 { 2151 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2152 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2153 2154 if (buflen < ext_len) { 2155 return -ENOSPC; 2156 } 2157 2158 *ext_backing_fmt = (QCowExtension) { 2159 .magic = cpu_to_be32(magic), 2160 .len = cpu_to_be32(len), 2161 }; 2162 2163 if (len) { 2164 memcpy(buf + sizeof(QCowExtension), s, len); 2165 } 2166 2167 return ext_len; 2168 } 2169 2170 /* 2171 * Updates the qcow2 header, including the variable length parts of it, i.e. 2172 * the backing file name and all extensions. qcow2 was not designed to allow 2173 * such changes, so if we run out of space (we can only use the first cluster) 2174 * this function may fail. 2175 * 2176 * Returns 0 on success, -errno in error cases. 2177 */ 2178 int qcow2_update_header(BlockDriverState *bs) 2179 { 2180 BDRVQcow2State *s = bs->opaque; 2181 QCowHeader *header; 2182 char *buf; 2183 size_t buflen = s->cluster_size; 2184 int ret; 2185 uint64_t total_size; 2186 uint32_t refcount_table_clusters; 2187 size_t header_length; 2188 Qcow2UnknownHeaderExtension *uext; 2189 2190 buf = qemu_blockalign(bs, buflen); 2191 2192 /* Header structure */ 2193 header = (QCowHeader*) buf; 2194 2195 if (buflen < sizeof(*header)) { 2196 ret = -ENOSPC; 2197 goto fail; 2198 } 2199 2200 header_length = sizeof(*header) + s->unknown_header_fields_size; 2201 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2202 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2203 2204 *header = (QCowHeader) { 2205 /* Version 2 fields */ 2206 .magic = cpu_to_be32(QCOW_MAGIC), 2207 .version = cpu_to_be32(s->qcow_version), 2208 .backing_file_offset = 0, 2209 .backing_file_size = 0, 2210 .cluster_bits = cpu_to_be32(s->cluster_bits), 2211 .size = cpu_to_be64(total_size), 2212 .crypt_method = cpu_to_be32(s->crypt_method_header), 2213 .l1_size = cpu_to_be32(s->l1_size), 2214 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2215 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2216 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2217 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2218 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2219 2220 /* Version 3 fields */ 2221 .incompatible_features = cpu_to_be64(s->incompatible_features), 2222 .compatible_features = cpu_to_be64(s->compatible_features), 2223 .autoclear_features = cpu_to_be64(s->autoclear_features), 2224 .refcount_order = cpu_to_be32(s->refcount_order), 2225 .header_length = cpu_to_be32(header_length), 2226 }; 2227 2228 /* For older versions, write a shorter header */ 2229 switch (s->qcow_version) { 2230 case 2: 2231 ret = offsetof(QCowHeader, incompatible_features); 2232 break; 2233 case 3: 2234 ret = sizeof(*header); 2235 break; 2236 default: 2237 ret = -EINVAL; 2238 goto fail; 2239 } 2240 2241 buf += ret; 2242 buflen -= ret; 2243 memset(buf, 0, buflen); 2244 2245 /* Preserve any unknown field in the header */ 2246 if (s->unknown_header_fields_size) { 2247 if (buflen < s->unknown_header_fields_size) { 2248 ret = -ENOSPC; 2249 goto fail; 2250 } 2251 2252 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2253 buf += s->unknown_header_fields_size; 2254 buflen -= s->unknown_header_fields_size; 2255 } 2256 2257 /* Backing file format header extension */ 2258 if (s->image_backing_format) { 2259 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2260 s->image_backing_format, 2261 strlen(s->image_backing_format), 2262 buflen); 2263 if (ret < 0) { 2264 goto fail; 2265 } 2266 2267 buf += ret; 2268 buflen -= ret; 2269 } 2270 2271 /* Full disk encryption header pointer extension */ 2272 if (s->crypto_header.offset != 0) { 2273 cpu_to_be64s(&s->crypto_header.offset); 2274 cpu_to_be64s(&s->crypto_header.length); 2275 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2276 &s->crypto_header, sizeof(s->crypto_header), 2277 buflen); 2278 be64_to_cpus(&s->crypto_header.offset); 2279 be64_to_cpus(&s->crypto_header.length); 2280 if (ret < 0) { 2281 goto fail; 2282 } 2283 buf += ret; 2284 buflen -= ret; 2285 } 2286 2287 /* Feature table */ 2288 if (s->qcow_version >= 3) { 2289 Qcow2Feature features[] = { 2290 { 2291 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2292 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2293 .name = "dirty bit", 2294 }, 2295 { 2296 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2297 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2298 .name = "corrupt bit", 2299 }, 2300 { 2301 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2302 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2303 .name = "lazy refcounts", 2304 }, 2305 }; 2306 2307 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2308 features, sizeof(features), buflen); 2309 if (ret < 0) { 2310 goto fail; 2311 } 2312 buf += ret; 2313 buflen -= ret; 2314 } 2315 2316 /* Bitmap extension */ 2317 if (s->nb_bitmaps > 0) { 2318 Qcow2BitmapHeaderExt bitmaps_header = { 2319 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2320 .bitmap_directory_size = 2321 cpu_to_be64(s->bitmap_directory_size), 2322 .bitmap_directory_offset = 2323 cpu_to_be64(s->bitmap_directory_offset) 2324 }; 2325 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2326 &bitmaps_header, sizeof(bitmaps_header), 2327 buflen); 2328 if (ret < 0) { 2329 goto fail; 2330 } 2331 buf += ret; 2332 buflen -= ret; 2333 } 2334 2335 /* Keep unknown header extensions */ 2336 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2337 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2338 if (ret < 0) { 2339 goto fail; 2340 } 2341 2342 buf += ret; 2343 buflen -= ret; 2344 } 2345 2346 /* End of header extensions */ 2347 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2348 if (ret < 0) { 2349 goto fail; 2350 } 2351 2352 buf += ret; 2353 buflen -= ret; 2354 2355 /* Backing file name */ 2356 if (s->image_backing_file) { 2357 size_t backing_file_len = strlen(s->image_backing_file); 2358 2359 if (buflen < backing_file_len) { 2360 ret = -ENOSPC; 2361 goto fail; 2362 } 2363 2364 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2365 strncpy(buf, s->image_backing_file, buflen); 2366 2367 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2368 header->backing_file_size = cpu_to_be32(backing_file_len); 2369 } 2370 2371 /* Write the new header */ 2372 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2373 if (ret < 0) { 2374 goto fail; 2375 } 2376 2377 ret = 0; 2378 fail: 2379 qemu_vfree(header); 2380 return ret; 2381 } 2382 2383 static int qcow2_change_backing_file(BlockDriverState *bs, 2384 const char *backing_file, const char *backing_fmt) 2385 { 2386 BDRVQcow2State *s = bs->opaque; 2387 2388 if (backing_file && strlen(backing_file) > 1023) { 2389 return -EINVAL; 2390 } 2391 2392 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2393 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2394 2395 g_free(s->image_backing_file); 2396 g_free(s->image_backing_format); 2397 2398 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2399 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2400 2401 return qcow2_update_header(bs); 2402 } 2403 2404 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2405 { 2406 if (g_str_equal(encryptfmt, "luks")) { 2407 return QCOW_CRYPT_LUKS; 2408 } else if (g_str_equal(encryptfmt, "aes")) { 2409 return QCOW_CRYPT_AES; 2410 } else { 2411 return -EINVAL; 2412 } 2413 } 2414 2415 static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, 2416 QemuOpts *opts, Error **errp) 2417 { 2418 BDRVQcow2State *s = bs->opaque; 2419 QCryptoBlockCreateOptions *cryptoopts = NULL; 2420 QCryptoBlock *crypto = NULL; 2421 int ret = -EINVAL; 2422 QDict *options, *encryptopts; 2423 int fmt; 2424 2425 options = qemu_opts_to_qdict(opts, NULL); 2426 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 2427 QDECREF(options); 2428 2429 fmt = qcow2_crypt_method_from_format(encryptfmt); 2430 2431 switch (fmt) { 2432 case QCOW_CRYPT_LUKS: 2433 cryptoopts = block_crypto_create_opts_init( 2434 Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); 2435 break; 2436 case QCOW_CRYPT_AES: 2437 cryptoopts = block_crypto_create_opts_init( 2438 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 2439 break; 2440 default: 2441 error_setg(errp, "Unknown encryption format '%s'", encryptfmt); 2442 break; 2443 } 2444 if (!cryptoopts) { 2445 ret = -EINVAL; 2446 goto out; 2447 } 2448 s->crypt_method_header = fmt; 2449 2450 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2451 qcow2_crypto_hdr_init_func, 2452 qcow2_crypto_hdr_write_func, 2453 bs, errp); 2454 if (!crypto) { 2455 ret = -EINVAL; 2456 goto out; 2457 } 2458 2459 ret = qcow2_update_header(bs); 2460 if (ret < 0) { 2461 error_setg_errno(errp, -ret, "Could not write encryption header"); 2462 goto out; 2463 } 2464 2465 out: 2466 QDECREF(encryptopts); 2467 qcrypto_block_free(crypto); 2468 qapi_free_QCryptoBlockCreateOptions(cryptoopts); 2469 return ret; 2470 } 2471 2472 2473 typedef struct PreallocCo { 2474 BlockDriverState *bs; 2475 uint64_t offset; 2476 uint64_t new_length; 2477 2478 int ret; 2479 } PreallocCo; 2480 2481 /** 2482 * Preallocates metadata structures for data clusters between @offset (in the 2483 * guest disk) and @new_length (which is thus generally the new guest disk 2484 * size). 2485 * 2486 * Returns: 0 on success, -errno on failure. 2487 */ 2488 static void coroutine_fn preallocate_co(void *opaque) 2489 { 2490 PreallocCo *params = opaque; 2491 BlockDriverState *bs = params->bs; 2492 uint64_t offset = params->offset; 2493 uint64_t new_length = params->new_length; 2494 BDRVQcow2State *s = bs->opaque; 2495 uint64_t bytes; 2496 uint64_t host_offset = 0; 2497 unsigned int cur_bytes; 2498 int ret; 2499 QCowL2Meta *meta; 2500 2501 qemu_co_mutex_lock(&s->lock); 2502 2503 assert(offset <= new_length); 2504 bytes = new_length - offset; 2505 2506 while (bytes) { 2507 cur_bytes = MIN(bytes, INT_MAX); 2508 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2509 &host_offset, &meta); 2510 if (ret < 0) { 2511 goto done; 2512 } 2513 2514 while (meta) { 2515 QCowL2Meta *next = meta->next; 2516 2517 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2518 if (ret < 0) { 2519 qcow2_free_any_clusters(bs, meta->alloc_offset, 2520 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2521 goto done; 2522 } 2523 2524 /* There are no dependent requests, but we need to remove our 2525 * request from the list of in-flight requests */ 2526 QLIST_REMOVE(meta, next_in_flight); 2527 2528 g_free(meta); 2529 meta = next; 2530 } 2531 2532 /* TODO Preallocate data if requested */ 2533 2534 bytes -= cur_bytes; 2535 offset += cur_bytes; 2536 } 2537 2538 /* 2539 * It is expected that the image file is large enough to actually contain 2540 * all of the allocated clusters (otherwise we get failing reads after 2541 * EOF). Extend the image to the last allocated sector. 2542 */ 2543 if (host_offset != 0) { 2544 uint8_t data = 0; 2545 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2546 &data, 1); 2547 if (ret < 0) { 2548 goto done; 2549 } 2550 } 2551 2552 ret = 0; 2553 2554 done: 2555 qemu_co_mutex_unlock(&s->lock); 2556 params->ret = ret; 2557 } 2558 2559 static int preallocate(BlockDriverState *bs, 2560 uint64_t offset, uint64_t new_length) 2561 { 2562 PreallocCo params = { 2563 .bs = bs, 2564 .offset = offset, 2565 .new_length = new_length, 2566 .ret = -EINPROGRESS, 2567 }; 2568 2569 if (qemu_in_coroutine()) { 2570 preallocate_co(¶ms); 2571 } else { 2572 Coroutine *co = qemu_coroutine_create(preallocate_co, ¶ms); 2573 bdrv_coroutine_enter(bs, co); 2574 BDRV_POLL_WHILE(bs, params.ret == -EINPROGRESS); 2575 } 2576 return params.ret; 2577 } 2578 2579 /* qcow2_refcount_metadata_size: 2580 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2581 * @cluster_size: size of a cluster, in bytes 2582 * @refcount_order: refcount bits power-of-2 exponent 2583 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2584 * needs to be 2585 * 2586 * Returns: Number of bytes required for refcount blocks and table metadata. 2587 */ 2588 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2589 int refcount_order, bool generous_increase, 2590 uint64_t *refblock_count) 2591 { 2592 /* 2593 * Every host cluster is reference-counted, including metadata (even 2594 * refcount metadata is recursively included). 2595 * 2596 * An accurate formula for the size of refcount metadata size is difficult 2597 * to derive. An easier method of calculation is finding the fixed point 2598 * where no further refcount blocks or table clusters are required to 2599 * reference count every cluster. 2600 */ 2601 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2602 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2603 int64_t table = 0; /* number of refcount table clusters */ 2604 int64_t blocks = 0; /* number of refcount block clusters */ 2605 int64_t last; 2606 int64_t n = 0; 2607 2608 do { 2609 last = n; 2610 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2611 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2612 n = clusters + blocks + table; 2613 2614 if (n == last && generous_increase) { 2615 clusters += DIV_ROUND_UP(table, 2); 2616 n = 0; /* force another loop */ 2617 generous_increase = false; 2618 } 2619 } while (n != last); 2620 2621 if (refblock_count) { 2622 *refblock_count = blocks; 2623 } 2624 2625 return (blocks + table) * cluster_size; 2626 } 2627 2628 /** 2629 * qcow2_calc_prealloc_size: 2630 * @total_size: virtual disk size in bytes 2631 * @cluster_size: cluster size in bytes 2632 * @refcount_order: refcount bits power-of-2 exponent 2633 * 2634 * Returns: Total number of bytes required for the fully allocated image 2635 * (including metadata). 2636 */ 2637 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2638 size_t cluster_size, 2639 int refcount_order) 2640 { 2641 int64_t meta_size = 0; 2642 uint64_t nl1e, nl2e; 2643 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2644 2645 /* header: 1 cluster */ 2646 meta_size += cluster_size; 2647 2648 /* total size of L2 tables */ 2649 nl2e = aligned_total_size / cluster_size; 2650 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2651 meta_size += nl2e * sizeof(uint64_t); 2652 2653 /* total size of L1 tables */ 2654 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2655 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2656 meta_size += nl1e * sizeof(uint64_t); 2657 2658 /* total size of refcount table and blocks */ 2659 meta_size += qcow2_refcount_metadata_size( 2660 (meta_size + aligned_total_size) / cluster_size, 2661 cluster_size, refcount_order, false, NULL); 2662 2663 return meta_size + aligned_total_size; 2664 } 2665 2666 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2667 { 2668 size_t cluster_size; 2669 int cluster_bits; 2670 2671 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2672 DEFAULT_CLUSTER_SIZE); 2673 cluster_bits = ctz32(cluster_size); 2674 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2675 (1 << cluster_bits) != cluster_size) 2676 { 2677 error_setg(errp, "Cluster size must be a power of two between %d and " 2678 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2679 return 0; 2680 } 2681 return cluster_size; 2682 } 2683 2684 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2685 { 2686 char *buf; 2687 int ret; 2688 2689 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2690 if (!buf) { 2691 ret = 3; /* default */ 2692 } else if (!strcmp(buf, "0.10")) { 2693 ret = 2; 2694 } else if (!strcmp(buf, "1.1")) { 2695 ret = 3; 2696 } else { 2697 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2698 ret = -EINVAL; 2699 } 2700 g_free(buf); 2701 return ret; 2702 } 2703 2704 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 2705 Error **errp) 2706 { 2707 uint64_t refcount_bits; 2708 2709 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 2710 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2711 error_setg(errp, "Refcount width must be a power of two and may not " 2712 "exceed 64 bits"); 2713 return 0; 2714 } 2715 2716 if (version < 3 && refcount_bits != 16) { 2717 error_setg(errp, "Different refcount widths than 16 bits require " 2718 "compatibility level 1.1 or above (use compat=1.1 or " 2719 "greater)"); 2720 return 0; 2721 } 2722 2723 return refcount_bits; 2724 } 2725 2726 static int qcow2_create2(const char *filename, int64_t total_size, 2727 const char *backing_file, const char *backing_format, 2728 int flags, size_t cluster_size, PreallocMode prealloc, 2729 QemuOpts *opts, int version, int refcount_order, 2730 const char *encryptfmt, Error **errp) 2731 { 2732 QDict *options; 2733 2734 /* 2735 * Open the image file and write a minimal qcow2 header. 2736 * 2737 * We keep things simple and start with a zero-sized image. We also 2738 * do without refcount blocks or a L1 table for now. We'll fix the 2739 * inconsistency later. 2740 * 2741 * We do need a refcount table because growing the refcount table means 2742 * allocating two new refcount blocks - the seconds of which would be at 2743 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2744 * size for any qcow2 image. 2745 */ 2746 BlockBackend *blk; 2747 QCowHeader *header; 2748 uint64_t* refcount_table; 2749 Error *local_err = NULL; 2750 int ret; 2751 2752 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2753 int64_t prealloc_size = 2754 qcow2_calc_prealloc_size(total_size, cluster_size, refcount_order); 2755 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, prealloc_size, &error_abort); 2756 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_str(prealloc), 2757 &error_abort); 2758 } 2759 2760 ret = bdrv_create_file(filename, opts, &local_err); 2761 if (ret < 0) { 2762 error_propagate(errp, local_err); 2763 return ret; 2764 } 2765 2766 blk = blk_new_open(filename, NULL, NULL, 2767 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 2768 &local_err); 2769 if (blk == NULL) { 2770 error_propagate(errp, local_err); 2771 return -EIO; 2772 } 2773 2774 blk_set_allow_write_beyond_eof(blk, true); 2775 2776 /* Write the header */ 2777 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2778 header = g_malloc0(cluster_size); 2779 *header = (QCowHeader) { 2780 .magic = cpu_to_be32(QCOW_MAGIC), 2781 .version = cpu_to_be32(version), 2782 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 2783 .size = cpu_to_be64(0), 2784 .l1_table_offset = cpu_to_be64(0), 2785 .l1_size = cpu_to_be32(0), 2786 .refcount_table_offset = cpu_to_be64(cluster_size), 2787 .refcount_table_clusters = cpu_to_be32(1), 2788 .refcount_order = cpu_to_be32(refcount_order), 2789 .header_length = cpu_to_be32(sizeof(*header)), 2790 }; 2791 2792 /* We'll update this to correct value later */ 2793 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2794 2795 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2796 header->compatible_features |= 2797 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2798 } 2799 2800 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2801 g_free(header); 2802 if (ret < 0) { 2803 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2804 goto out; 2805 } 2806 2807 /* Write a refcount table with one refcount block */ 2808 refcount_table = g_malloc0(2 * cluster_size); 2809 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2810 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2811 g_free(refcount_table); 2812 2813 if (ret < 0) { 2814 error_setg_errno(errp, -ret, "Could not write refcount table"); 2815 goto out; 2816 } 2817 2818 blk_unref(blk); 2819 blk = NULL; 2820 2821 /* 2822 * And now open the image and make it consistent first (i.e. increase the 2823 * refcount of the cluster that is occupied by the header and the refcount 2824 * table) 2825 */ 2826 options = qdict_new(); 2827 qdict_put_str(options, "driver", "qcow2"); 2828 blk = blk_new_open(filename, NULL, options, 2829 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 2830 &local_err); 2831 if (blk == NULL) { 2832 error_propagate(errp, local_err); 2833 ret = -EIO; 2834 goto out; 2835 } 2836 2837 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2838 if (ret < 0) { 2839 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2840 "header and refcount table"); 2841 goto out; 2842 2843 } else if (ret != 0) { 2844 error_report("Huh, first cluster in empty image is already in use?"); 2845 abort(); 2846 } 2847 2848 /* Create a full header (including things like feature table) */ 2849 ret = qcow2_update_header(blk_bs(blk)); 2850 if (ret < 0) { 2851 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2852 goto out; 2853 } 2854 2855 /* Okay, now that we have a valid image, let's give it the right size */ 2856 ret = blk_truncate(blk, total_size, PREALLOC_MODE_OFF, errp); 2857 if (ret < 0) { 2858 error_prepend(errp, "Could not resize image: "); 2859 goto out; 2860 } 2861 2862 /* Want a backing file? There you go.*/ 2863 if (backing_file) { 2864 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2865 if (ret < 0) { 2866 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2867 "with format '%s'", backing_file, backing_format); 2868 goto out; 2869 } 2870 } 2871 2872 /* Want encryption? There you go. */ 2873 if (encryptfmt) { 2874 ret = qcow2_set_up_encryption(blk_bs(blk), encryptfmt, opts, errp); 2875 if (ret < 0) { 2876 goto out; 2877 } 2878 } 2879 2880 /* And if we're supposed to preallocate metadata, do that now */ 2881 if (prealloc != PREALLOC_MODE_OFF) { 2882 ret = preallocate(blk_bs(blk), 0, total_size); 2883 if (ret < 0) { 2884 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2885 goto out; 2886 } 2887 } 2888 2889 blk_unref(blk); 2890 blk = NULL; 2891 2892 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 2893 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 2894 * have to setup decryption context. We're not doing any I/O on the top 2895 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 2896 * not have effect. 2897 */ 2898 options = qdict_new(); 2899 qdict_put_str(options, "driver", "qcow2"); 2900 blk = blk_new_open(filename, NULL, options, 2901 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 2902 &local_err); 2903 if (blk == NULL) { 2904 error_propagate(errp, local_err); 2905 ret = -EIO; 2906 goto out; 2907 } 2908 2909 ret = 0; 2910 out: 2911 if (blk) { 2912 blk_unref(blk); 2913 } 2914 return ret; 2915 } 2916 2917 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2918 { 2919 char *backing_file = NULL; 2920 char *backing_fmt = NULL; 2921 char *buf = NULL; 2922 uint64_t size = 0; 2923 int flags = 0; 2924 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2925 PreallocMode prealloc; 2926 int version; 2927 uint64_t refcount_bits; 2928 int refcount_order; 2929 char *encryptfmt = NULL; 2930 Error *local_err = NULL; 2931 int ret; 2932 2933 /* Read out options */ 2934 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2935 BDRV_SECTOR_SIZE); 2936 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2937 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2938 encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 2939 if (encryptfmt) { 2940 if (qemu_opt_get(opts, BLOCK_OPT_ENCRYPT)) { 2941 error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and " 2942 BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive"); 2943 ret = -EINVAL; 2944 goto finish; 2945 } 2946 } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2947 encryptfmt = g_strdup("aes"); 2948 } 2949 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 2950 if (local_err) { 2951 error_propagate(errp, local_err); 2952 ret = -EINVAL; 2953 goto finish; 2954 } 2955 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2956 prealloc = qapi_enum_parse(&PreallocMode_lookup, buf, 2957 PREALLOC_MODE_OFF, &local_err); 2958 if (local_err) { 2959 error_propagate(errp, local_err); 2960 ret = -EINVAL; 2961 goto finish; 2962 } 2963 2964 version = qcow2_opt_get_version_del(opts, &local_err); 2965 if (local_err) { 2966 error_propagate(errp, local_err); 2967 ret = -EINVAL; 2968 goto finish; 2969 } 2970 2971 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2972 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2973 } 2974 2975 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2976 error_setg(errp, "Backing file and preallocation cannot be used at " 2977 "the same time"); 2978 ret = -EINVAL; 2979 goto finish; 2980 } 2981 2982 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2983 error_setg(errp, "Lazy refcounts only supported with compatibility " 2984 "level 1.1 and above (use compat=1.1 or greater)"); 2985 ret = -EINVAL; 2986 goto finish; 2987 } 2988 2989 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 2990 if (local_err) { 2991 error_propagate(errp, local_err); 2992 ret = -EINVAL; 2993 goto finish; 2994 } 2995 2996 refcount_order = ctz32(refcount_bits); 2997 2998 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2999 cluster_size, prealloc, opts, version, refcount_order, 3000 encryptfmt, &local_err); 3001 error_propagate(errp, local_err); 3002 3003 finish: 3004 g_free(backing_file); 3005 g_free(backing_fmt); 3006 g_free(encryptfmt); 3007 g_free(buf); 3008 return ret; 3009 } 3010 3011 3012 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3013 { 3014 int64_t nr; 3015 int res; 3016 3017 /* Clamp to image length, before checking status of underlying sectors */ 3018 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3019 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3020 } 3021 3022 if (!bytes) { 3023 return true; 3024 } 3025 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3026 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3027 } 3028 3029 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3030 int64_t offset, int bytes, BdrvRequestFlags flags) 3031 { 3032 int ret; 3033 BDRVQcow2State *s = bs->opaque; 3034 3035 uint32_t head = offset % s->cluster_size; 3036 uint32_t tail = (offset + bytes) % s->cluster_size; 3037 3038 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3039 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3040 tail = 0; 3041 } 3042 3043 if (head || tail) { 3044 uint64_t off; 3045 unsigned int nr; 3046 3047 assert(head + bytes <= s->cluster_size); 3048 3049 /* check whether remainder of cluster already reads as zero */ 3050 if (!(is_zero(bs, offset - head, head) && 3051 is_zero(bs, offset + bytes, 3052 tail ? s->cluster_size - tail : 0))) { 3053 return -ENOTSUP; 3054 } 3055 3056 qemu_co_mutex_lock(&s->lock); 3057 /* We can have new write after previous check */ 3058 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3059 bytes = s->cluster_size; 3060 nr = s->cluster_size; 3061 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3062 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3063 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3064 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3065 qemu_co_mutex_unlock(&s->lock); 3066 return -ENOTSUP; 3067 } 3068 } else { 3069 qemu_co_mutex_lock(&s->lock); 3070 } 3071 3072 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3073 3074 /* Whatever is left can use real zero clusters */ 3075 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3076 qemu_co_mutex_unlock(&s->lock); 3077 3078 return ret; 3079 } 3080 3081 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3082 int64_t offset, int bytes) 3083 { 3084 int ret; 3085 BDRVQcow2State *s = bs->opaque; 3086 3087 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3088 assert(bytes < s->cluster_size); 3089 /* Ignore partial clusters, except for the special case of the 3090 * complete partial cluster at the end of an unaligned file */ 3091 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3092 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3093 return -ENOTSUP; 3094 } 3095 } 3096 3097 qemu_co_mutex_lock(&s->lock); 3098 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3099 false); 3100 qemu_co_mutex_unlock(&s->lock); 3101 return ret; 3102 } 3103 3104 static int qcow2_truncate(BlockDriverState *bs, int64_t offset, 3105 PreallocMode prealloc, Error **errp) 3106 { 3107 BDRVQcow2State *s = bs->opaque; 3108 uint64_t old_length; 3109 int64_t new_l1_size; 3110 int ret; 3111 3112 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3113 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3114 { 3115 error_setg(errp, "Unsupported preallocation mode '%s'", 3116 PreallocMode_str(prealloc)); 3117 return -ENOTSUP; 3118 } 3119 3120 if (offset & 511) { 3121 error_setg(errp, "The new size must be a multiple of 512"); 3122 return -EINVAL; 3123 } 3124 3125 /* cannot proceed if image has snapshots */ 3126 if (s->nb_snapshots) { 3127 error_setg(errp, "Can't resize an image which has snapshots"); 3128 return -ENOTSUP; 3129 } 3130 3131 /* cannot proceed if image has bitmaps */ 3132 if (s->nb_bitmaps) { 3133 /* TODO: resize bitmaps in the image */ 3134 error_setg(errp, "Can't resize an image which has bitmaps"); 3135 return -ENOTSUP; 3136 } 3137 3138 old_length = bs->total_sectors * 512; 3139 new_l1_size = size_to_l1(s, offset); 3140 3141 if (offset < old_length) { 3142 int64_t last_cluster, old_file_size; 3143 if (prealloc != PREALLOC_MODE_OFF) { 3144 error_setg(errp, 3145 "Preallocation can't be used for shrinking an image"); 3146 return -EINVAL; 3147 } 3148 3149 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3150 old_length - ROUND_UP(offset, 3151 s->cluster_size), 3152 QCOW2_DISCARD_ALWAYS, true); 3153 if (ret < 0) { 3154 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3155 return ret; 3156 } 3157 3158 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3159 if (ret < 0) { 3160 error_setg_errno(errp, -ret, 3161 "Failed to reduce the number of L2 tables"); 3162 return ret; 3163 } 3164 3165 ret = qcow2_shrink_reftable(bs); 3166 if (ret < 0) { 3167 error_setg_errno(errp, -ret, 3168 "Failed to discard unused refblocks"); 3169 return ret; 3170 } 3171 3172 old_file_size = bdrv_getlength(bs->file->bs); 3173 if (old_file_size < 0) { 3174 error_setg_errno(errp, -old_file_size, 3175 "Failed to inquire current file length"); 3176 return old_file_size; 3177 } 3178 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3179 if (last_cluster < 0) { 3180 error_setg_errno(errp, -last_cluster, 3181 "Failed to find the last cluster"); 3182 return last_cluster; 3183 } 3184 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3185 Error *local_err = NULL; 3186 3187 bdrv_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3188 PREALLOC_MODE_OFF, &local_err); 3189 if (local_err) { 3190 warn_reportf_err(local_err, 3191 "Failed to truncate the tail of the image: "); 3192 } 3193 } 3194 } else { 3195 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3196 if (ret < 0) { 3197 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3198 return ret; 3199 } 3200 } 3201 3202 switch (prealloc) { 3203 case PREALLOC_MODE_OFF: 3204 break; 3205 3206 case PREALLOC_MODE_METADATA: 3207 ret = preallocate(bs, old_length, offset); 3208 if (ret < 0) { 3209 error_setg_errno(errp, -ret, "Preallocation failed"); 3210 return ret; 3211 } 3212 break; 3213 3214 case PREALLOC_MODE_FALLOC: 3215 case PREALLOC_MODE_FULL: 3216 { 3217 int64_t allocation_start, host_offset, guest_offset; 3218 int64_t clusters_allocated; 3219 int64_t old_file_size, new_file_size; 3220 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3221 3222 old_file_size = bdrv_getlength(bs->file->bs); 3223 if (old_file_size < 0) { 3224 error_setg_errno(errp, -old_file_size, 3225 "Failed to inquire current file length"); 3226 return old_file_size; 3227 } 3228 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3229 3230 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3231 s->cluster_size); 3232 3233 /* This is an overestimation; we will not actually allocate space for 3234 * these in the file but just make sure the new refcount structures are 3235 * able to cover them so we will not have to allocate new refblocks 3236 * while entering the data blocks in the potentially new L2 tables. 3237 * (We do not actually care where the L2 tables are placed. Maybe they 3238 * are already allocated or they can be placed somewhere before 3239 * @old_file_size. It does not matter because they will be fully 3240 * allocated automatically, so they do not need to be covered by the 3241 * preallocation. All that matters is that we will not have to allocate 3242 * new refcount structures for them.) */ 3243 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3244 s->cluster_size / sizeof(uint64_t)); 3245 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3246 * table for a potential head/tail */ 3247 nb_new_l2_tables++; 3248 3249 allocation_start = qcow2_refcount_area(bs, old_file_size, 3250 nb_new_data_clusters + 3251 nb_new_l2_tables, 3252 true, 0, 0); 3253 if (allocation_start < 0) { 3254 error_setg_errno(errp, -allocation_start, 3255 "Failed to resize refcount structures"); 3256 return allocation_start; 3257 } 3258 3259 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3260 nb_new_data_clusters); 3261 if (clusters_allocated < 0) { 3262 error_setg_errno(errp, -clusters_allocated, 3263 "Failed to allocate data clusters"); 3264 return -clusters_allocated; 3265 } 3266 3267 assert(clusters_allocated == nb_new_data_clusters); 3268 3269 /* Allocate the data area */ 3270 new_file_size = allocation_start + 3271 nb_new_data_clusters * s->cluster_size; 3272 ret = bdrv_truncate(bs->file, new_file_size, prealloc, errp); 3273 if (ret < 0) { 3274 error_prepend(errp, "Failed to resize underlying file: "); 3275 qcow2_free_clusters(bs, allocation_start, 3276 nb_new_data_clusters * s->cluster_size, 3277 QCOW2_DISCARD_OTHER); 3278 return ret; 3279 } 3280 3281 /* Create the necessary L2 entries */ 3282 host_offset = allocation_start; 3283 guest_offset = old_length; 3284 while (nb_new_data_clusters) { 3285 int64_t nb_clusters = MIN( 3286 nb_new_data_clusters, 3287 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3288 QCowL2Meta allocation = { 3289 .offset = guest_offset, 3290 .alloc_offset = host_offset, 3291 .nb_clusters = nb_clusters, 3292 }; 3293 qemu_co_queue_init(&allocation.dependent_requests); 3294 3295 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3296 if (ret < 0) { 3297 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3298 qcow2_free_clusters(bs, host_offset, 3299 nb_new_data_clusters * s->cluster_size, 3300 QCOW2_DISCARD_OTHER); 3301 return ret; 3302 } 3303 3304 guest_offset += nb_clusters * s->cluster_size; 3305 host_offset += nb_clusters * s->cluster_size; 3306 nb_new_data_clusters -= nb_clusters; 3307 } 3308 break; 3309 } 3310 3311 default: 3312 g_assert_not_reached(); 3313 } 3314 3315 if (prealloc != PREALLOC_MODE_OFF) { 3316 /* Flush metadata before actually changing the image size */ 3317 ret = bdrv_flush(bs); 3318 if (ret < 0) { 3319 error_setg_errno(errp, -ret, 3320 "Failed to flush the preallocated area to disk"); 3321 return ret; 3322 } 3323 } 3324 3325 /* write updated header.size */ 3326 offset = cpu_to_be64(offset); 3327 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3328 &offset, sizeof(uint64_t)); 3329 if (ret < 0) { 3330 error_setg_errno(errp, -ret, "Failed to update the image size"); 3331 return ret; 3332 } 3333 3334 s->l1_vm_state_index = new_l1_size; 3335 return 0; 3336 } 3337 3338 /* XXX: put compressed sectors first, then all the cluster aligned 3339 tables to avoid losing bytes in alignment */ 3340 static coroutine_fn int 3341 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 3342 uint64_t bytes, QEMUIOVector *qiov) 3343 { 3344 BDRVQcow2State *s = bs->opaque; 3345 QEMUIOVector hd_qiov; 3346 struct iovec iov; 3347 z_stream strm; 3348 int ret, out_len; 3349 uint8_t *buf, *out_buf; 3350 int64_t cluster_offset; 3351 3352 if (bytes == 0) { 3353 /* align end of file to a sector boundary to ease reading with 3354 sector based I/Os */ 3355 cluster_offset = bdrv_getlength(bs->file->bs); 3356 if (cluster_offset < 0) { 3357 return cluster_offset; 3358 } 3359 return bdrv_truncate(bs->file, cluster_offset, PREALLOC_MODE_OFF, NULL); 3360 } 3361 3362 if (offset_into_cluster(s, offset)) { 3363 return -EINVAL; 3364 } 3365 3366 buf = qemu_blockalign(bs, s->cluster_size); 3367 if (bytes != s->cluster_size) { 3368 if (bytes > s->cluster_size || 3369 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 3370 { 3371 qemu_vfree(buf); 3372 return -EINVAL; 3373 } 3374 /* Zero-pad last write if image size is not cluster aligned */ 3375 memset(buf + bytes, 0, s->cluster_size - bytes); 3376 } 3377 qemu_iovec_to_buf(qiov, 0, buf, bytes); 3378 3379 out_buf = g_malloc(s->cluster_size); 3380 3381 /* best compression, small window, no zlib header */ 3382 memset(&strm, 0, sizeof(strm)); 3383 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 3384 Z_DEFLATED, -12, 3385 9, Z_DEFAULT_STRATEGY); 3386 if (ret != 0) { 3387 ret = -EINVAL; 3388 goto fail; 3389 } 3390 3391 strm.avail_in = s->cluster_size; 3392 strm.next_in = (uint8_t *)buf; 3393 strm.avail_out = s->cluster_size; 3394 strm.next_out = out_buf; 3395 3396 ret = deflate(&strm, Z_FINISH); 3397 if (ret != Z_STREAM_END && ret != Z_OK) { 3398 deflateEnd(&strm); 3399 ret = -EINVAL; 3400 goto fail; 3401 } 3402 out_len = strm.next_out - out_buf; 3403 3404 deflateEnd(&strm); 3405 3406 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 3407 /* could not compress: write normal cluster */ 3408 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 3409 if (ret < 0) { 3410 goto fail; 3411 } 3412 goto success; 3413 } 3414 3415 qemu_co_mutex_lock(&s->lock); 3416 cluster_offset = 3417 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); 3418 if (!cluster_offset) { 3419 qemu_co_mutex_unlock(&s->lock); 3420 ret = -EIO; 3421 goto fail; 3422 } 3423 cluster_offset &= s->cluster_offset_mask; 3424 3425 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 3426 qemu_co_mutex_unlock(&s->lock); 3427 if (ret < 0) { 3428 goto fail; 3429 } 3430 3431 iov = (struct iovec) { 3432 .iov_base = out_buf, 3433 .iov_len = out_len, 3434 }; 3435 qemu_iovec_init_external(&hd_qiov, &iov, 1); 3436 3437 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 3438 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 3439 if (ret < 0) { 3440 goto fail; 3441 } 3442 success: 3443 ret = 0; 3444 fail: 3445 qemu_vfree(buf); 3446 g_free(out_buf); 3447 return ret; 3448 } 3449 3450 static int make_completely_empty(BlockDriverState *bs) 3451 { 3452 BDRVQcow2State *s = bs->opaque; 3453 Error *local_err = NULL; 3454 int ret, l1_clusters; 3455 int64_t offset; 3456 uint64_t *new_reftable = NULL; 3457 uint64_t rt_entry, l1_size2; 3458 struct { 3459 uint64_t l1_offset; 3460 uint64_t reftable_offset; 3461 uint32_t reftable_clusters; 3462 } QEMU_PACKED l1_ofs_rt_ofs_cls; 3463 3464 ret = qcow2_cache_empty(bs, s->l2_table_cache); 3465 if (ret < 0) { 3466 goto fail; 3467 } 3468 3469 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 3470 if (ret < 0) { 3471 goto fail; 3472 } 3473 3474 /* Refcounts will be broken utterly */ 3475 ret = qcow2_mark_dirty(bs); 3476 if (ret < 0) { 3477 goto fail; 3478 } 3479 3480 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 3481 3482 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 3483 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 3484 3485 /* After this call, neither the in-memory nor the on-disk refcount 3486 * information accurately describe the actual references */ 3487 3488 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 3489 l1_clusters * s->cluster_size, 0); 3490 if (ret < 0) { 3491 goto fail_broken_refcounts; 3492 } 3493 memset(s->l1_table, 0, l1_size2); 3494 3495 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 3496 3497 /* Overwrite enough clusters at the beginning of the sectors to place 3498 * the refcount table, a refcount block and the L1 table in; this may 3499 * overwrite parts of the existing refcount and L1 table, which is not 3500 * an issue because the dirty flag is set, complete data loss is in fact 3501 * desired and partial data loss is consequently fine as well */ 3502 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 3503 (2 + l1_clusters) * s->cluster_size, 0); 3504 /* This call (even if it failed overall) may have overwritten on-disk 3505 * refcount structures; in that case, the in-memory refcount information 3506 * will probably differ from the on-disk information which makes the BDS 3507 * unusable */ 3508 if (ret < 0) { 3509 goto fail_broken_refcounts; 3510 } 3511 3512 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 3513 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 3514 3515 /* "Create" an empty reftable (one cluster) directly after the image 3516 * header and an empty L1 table three clusters after the image header; 3517 * the cluster between those two will be used as the first refblock */ 3518 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 3519 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 3520 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 3521 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 3522 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 3523 if (ret < 0) { 3524 goto fail_broken_refcounts; 3525 } 3526 3527 s->l1_table_offset = 3 * s->cluster_size; 3528 3529 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 3530 if (!new_reftable) { 3531 ret = -ENOMEM; 3532 goto fail_broken_refcounts; 3533 } 3534 3535 s->refcount_table_offset = s->cluster_size; 3536 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 3537 s->max_refcount_table_index = 0; 3538 3539 g_free(s->refcount_table); 3540 s->refcount_table = new_reftable; 3541 new_reftable = NULL; 3542 3543 /* Now the in-memory refcount information again corresponds to the on-disk 3544 * information (reftable is empty and no refblocks (the refblock cache is 3545 * empty)); however, this means some clusters (e.g. the image header) are 3546 * referenced, but not refcounted, but the normal qcow2 code assumes that 3547 * the in-memory information is always correct */ 3548 3549 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 3550 3551 /* Enter the first refblock into the reftable */ 3552 rt_entry = cpu_to_be64(2 * s->cluster_size); 3553 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 3554 &rt_entry, sizeof(rt_entry)); 3555 if (ret < 0) { 3556 goto fail_broken_refcounts; 3557 } 3558 s->refcount_table[0] = 2 * s->cluster_size; 3559 3560 s->free_cluster_index = 0; 3561 assert(3 + l1_clusters <= s->refcount_block_size); 3562 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 3563 if (offset < 0) { 3564 ret = offset; 3565 goto fail_broken_refcounts; 3566 } else if (offset > 0) { 3567 error_report("First cluster in emptied image is in use"); 3568 abort(); 3569 } 3570 3571 /* Now finally the in-memory information corresponds to the on-disk 3572 * structures and is correct */ 3573 ret = qcow2_mark_clean(bs); 3574 if (ret < 0) { 3575 goto fail; 3576 } 3577 3578 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 3579 PREALLOC_MODE_OFF, &local_err); 3580 if (ret < 0) { 3581 error_report_err(local_err); 3582 goto fail; 3583 } 3584 3585 return 0; 3586 3587 fail_broken_refcounts: 3588 /* The BDS is unusable at this point. If we wanted to make it usable, we 3589 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 3590 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 3591 * again. However, because the functions which could have caused this error 3592 * path to be taken are used by those functions as well, it's very likely 3593 * that that sequence will fail as well. Therefore, just eject the BDS. */ 3594 bs->drv = NULL; 3595 3596 fail: 3597 g_free(new_reftable); 3598 return ret; 3599 } 3600 3601 static int qcow2_make_empty(BlockDriverState *bs) 3602 { 3603 BDRVQcow2State *s = bs->opaque; 3604 uint64_t offset, end_offset; 3605 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 3606 int l1_clusters, ret = 0; 3607 3608 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 3609 3610 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 3611 3 + l1_clusters <= s->refcount_block_size && 3612 s->crypt_method_header != QCOW_CRYPT_LUKS) { 3613 /* The following function only works for qcow2 v3 images (it 3614 * requires the dirty flag) and only as long as there are no 3615 * features that reserve extra clusters (such as snapshots, 3616 * LUKS header, or persistent bitmaps), because it completely 3617 * empties the image. Furthermore, the L1 table and three 3618 * additional clusters (image header, refcount table, one 3619 * refcount block) have to fit inside one refcount block. */ 3620 return make_completely_empty(bs); 3621 } 3622 3623 /* This fallback code simply discards every active cluster; this is slow, 3624 * but works in all cases */ 3625 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 3626 for (offset = 0; offset < end_offset; offset += step) { 3627 /* As this function is generally used after committing an external 3628 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 3629 * default action for this kind of discard is to pass the discard, 3630 * which will ideally result in an actually smaller image file, as 3631 * is probably desired. */ 3632 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 3633 QCOW2_DISCARD_SNAPSHOT, true); 3634 if (ret < 0) { 3635 break; 3636 } 3637 } 3638 3639 return ret; 3640 } 3641 3642 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 3643 { 3644 BDRVQcow2State *s = bs->opaque; 3645 int ret; 3646 3647 qemu_co_mutex_lock(&s->lock); 3648 ret = qcow2_cache_write(bs, s->l2_table_cache); 3649 if (ret < 0) { 3650 qemu_co_mutex_unlock(&s->lock); 3651 return ret; 3652 } 3653 3654 if (qcow2_need_accurate_refcounts(s)) { 3655 ret = qcow2_cache_write(bs, s->refcount_block_cache); 3656 if (ret < 0) { 3657 qemu_co_mutex_unlock(&s->lock); 3658 return ret; 3659 } 3660 } 3661 qemu_co_mutex_unlock(&s->lock); 3662 3663 return 0; 3664 } 3665 3666 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 3667 Error **errp) 3668 { 3669 Error *local_err = NULL; 3670 BlockMeasureInfo *info; 3671 uint64_t required = 0; /* bytes that contribute to required size */ 3672 uint64_t virtual_size; /* disk size as seen by guest */ 3673 uint64_t refcount_bits; 3674 uint64_t l2_tables; 3675 size_t cluster_size; 3676 int version; 3677 char *optstr; 3678 PreallocMode prealloc; 3679 bool has_backing_file; 3680 3681 /* Parse image creation options */ 3682 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 3683 if (local_err) { 3684 goto err; 3685 } 3686 3687 version = qcow2_opt_get_version_del(opts, &local_err); 3688 if (local_err) { 3689 goto err; 3690 } 3691 3692 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 3693 if (local_err) { 3694 goto err; 3695 } 3696 3697 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 3698 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 3699 PREALLOC_MODE_OFF, &local_err); 3700 g_free(optstr); 3701 if (local_err) { 3702 goto err; 3703 } 3704 3705 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 3706 has_backing_file = !!optstr; 3707 g_free(optstr); 3708 3709 virtual_size = align_offset(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 3710 cluster_size); 3711 3712 /* Check that virtual disk size is valid */ 3713 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 3714 cluster_size / sizeof(uint64_t)); 3715 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 3716 error_setg(&local_err, "The image size is too large " 3717 "(try using a larger cluster size)"); 3718 goto err; 3719 } 3720 3721 /* Account for input image */ 3722 if (in_bs) { 3723 int64_t ssize = bdrv_getlength(in_bs); 3724 if (ssize < 0) { 3725 error_setg_errno(&local_err, -ssize, 3726 "Unable to get image virtual_size"); 3727 goto err; 3728 } 3729 3730 virtual_size = align_offset(ssize, cluster_size); 3731 3732 if (has_backing_file) { 3733 /* We don't how much of the backing chain is shared by the input 3734 * image and the new image file. In the worst case the new image's 3735 * backing file has nothing in common with the input image. Be 3736 * conservative and assume all clusters need to be written. 3737 */ 3738 required = virtual_size; 3739 } else { 3740 int64_t offset; 3741 int64_t pnum = 0; 3742 3743 for (offset = 0; offset < ssize; offset += pnum) { 3744 int ret; 3745 3746 ret = bdrv_block_status_above(in_bs, NULL, offset, 3747 ssize - offset, &pnum, NULL, 3748 NULL); 3749 if (ret < 0) { 3750 error_setg_errno(&local_err, -ret, 3751 "Unable to get block status"); 3752 goto err; 3753 } 3754 3755 if (ret & BDRV_BLOCK_ZERO) { 3756 /* Skip zero regions (safe with no backing file) */ 3757 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 3758 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 3759 /* Extend pnum to end of cluster for next iteration */ 3760 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 3761 3762 /* Count clusters we've seen */ 3763 required += offset % cluster_size + pnum; 3764 } 3765 } 3766 } 3767 } 3768 3769 /* Take into account preallocation. Nothing special is needed for 3770 * PREALLOC_MODE_METADATA since metadata is always counted. 3771 */ 3772 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 3773 required = virtual_size; 3774 } 3775 3776 info = g_new(BlockMeasureInfo, 1); 3777 info->fully_allocated = 3778 qcow2_calc_prealloc_size(virtual_size, cluster_size, 3779 ctz32(refcount_bits)); 3780 3781 /* Remove data clusters that are not required. This overestimates the 3782 * required size because metadata needed for the fully allocated file is 3783 * still counted. 3784 */ 3785 info->required = info->fully_allocated - virtual_size + required; 3786 return info; 3787 3788 err: 3789 error_propagate(errp, local_err); 3790 return NULL; 3791 } 3792 3793 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3794 { 3795 BDRVQcow2State *s = bs->opaque; 3796 bdi->unallocated_blocks_are_zero = true; 3797 bdi->cluster_size = s->cluster_size; 3798 bdi->vm_state_offset = qcow2_vm_state_offset(s); 3799 return 0; 3800 } 3801 3802 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 3803 { 3804 BDRVQcow2State *s = bs->opaque; 3805 ImageInfoSpecific *spec_info; 3806 QCryptoBlockInfo *encrypt_info = NULL; 3807 3808 if (s->crypto != NULL) { 3809 encrypt_info = qcrypto_block_get_info(s->crypto, &error_abort); 3810 } 3811 3812 spec_info = g_new(ImageInfoSpecific, 1); 3813 *spec_info = (ImageInfoSpecific){ 3814 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 3815 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 3816 }; 3817 if (s->qcow_version == 2) { 3818 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 3819 .compat = g_strdup("0.10"), 3820 .refcount_bits = s->refcount_bits, 3821 }; 3822 } else if (s->qcow_version == 3) { 3823 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 3824 .compat = g_strdup("1.1"), 3825 .lazy_refcounts = s->compatible_features & 3826 QCOW2_COMPAT_LAZY_REFCOUNTS, 3827 .has_lazy_refcounts = true, 3828 .corrupt = s->incompatible_features & 3829 QCOW2_INCOMPAT_CORRUPT, 3830 .has_corrupt = true, 3831 .refcount_bits = s->refcount_bits, 3832 }; 3833 } else { 3834 /* if this assertion fails, this probably means a new version was 3835 * added without having it covered here */ 3836 assert(false); 3837 } 3838 3839 if (encrypt_info) { 3840 ImageInfoSpecificQCow2Encryption *qencrypt = 3841 g_new(ImageInfoSpecificQCow2Encryption, 1); 3842 switch (encrypt_info->format) { 3843 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 3844 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 3845 qencrypt->u.aes = encrypt_info->u.qcow; 3846 break; 3847 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 3848 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 3849 qencrypt->u.luks = encrypt_info->u.luks; 3850 break; 3851 default: 3852 abort(); 3853 } 3854 /* Since we did shallow copy above, erase any pointers 3855 * in the original info */ 3856 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 3857 qapi_free_QCryptoBlockInfo(encrypt_info); 3858 3859 spec_info->u.qcow2.data->has_encrypt = true; 3860 spec_info->u.qcow2.data->encrypt = qencrypt; 3861 } 3862 3863 return spec_info; 3864 } 3865 3866 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 3867 int64_t pos) 3868 { 3869 BDRVQcow2State *s = bs->opaque; 3870 3871 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 3872 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 3873 qiov->size, qiov, 0); 3874 } 3875 3876 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 3877 int64_t pos) 3878 { 3879 BDRVQcow2State *s = bs->opaque; 3880 3881 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 3882 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 3883 qiov->size, qiov, 0); 3884 } 3885 3886 /* 3887 * Downgrades an image's version. To achieve this, any incompatible features 3888 * have to be removed. 3889 */ 3890 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 3891 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 3892 { 3893 BDRVQcow2State *s = bs->opaque; 3894 int current_version = s->qcow_version; 3895 int ret; 3896 3897 if (target_version == current_version) { 3898 return 0; 3899 } else if (target_version > current_version) { 3900 return -EINVAL; 3901 } else if (target_version != 2) { 3902 return -EINVAL; 3903 } 3904 3905 if (s->refcount_order != 4) { 3906 error_report("compat=0.10 requires refcount_bits=16"); 3907 return -ENOTSUP; 3908 } 3909 3910 /* clear incompatible features */ 3911 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 3912 ret = qcow2_mark_clean(bs); 3913 if (ret < 0) { 3914 return ret; 3915 } 3916 } 3917 3918 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 3919 * the first place; if that happens nonetheless, returning -ENOTSUP is the 3920 * best thing to do anyway */ 3921 3922 if (s->incompatible_features) { 3923 return -ENOTSUP; 3924 } 3925 3926 /* since we can ignore compatible features, we can set them to 0 as well */ 3927 s->compatible_features = 0; 3928 /* if lazy refcounts have been used, they have already been fixed through 3929 * clearing the dirty flag */ 3930 3931 /* clearing autoclear features is trivial */ 3932 s->autoclear_features = 0; 3933 3934 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 3935 if (ret < 0) { 3936 return ret; 3937 } 3938 3939 s->qcow_version = target_version; 3940 ret = qcow2_update_header(bs); 3941 if (ret < 0) { 3942 s->qcow_version = current_version; 3943 return ret; 3944 } 3945 return 0; 3946 } 3947 3948 typedef enum Qcow2AmendOperation { 3949 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 3950 * statically initialized to so that the helper CB can discern the first 3951 * invocation from an operation change */ 3952 QCOW2_NO_OPERATION = 0, 3953 3954 QCOW2_CHANGING_REFCOUNT_ORDER, 3955 QCOW2_DOWNGRADING, 3956 } Qcow2AmendOperation; 3957 3958 typedef struct Qcow2AmendHelperCBInfo { 3959 /* The code coordinating the amend operations should only modify 3960 * these four fields; the rest will be managed by the CB */ 3961 BlockDriverAmendStatusCB *original_status_cb; 3962 void *original_cb_opaque; 3963 3964 Qcow2AmendOperation current_operation; 3965 3966 /* Total number of operations to perform (only set once) */ 3967 int total_operations; 3968 3969 /* The following fields are managed by the CB */ 3970 3971 /* Number of operations completed */ 3972 int operations_completed; 3973 3974 /* Cumulative offset of all completed operations */ 3975 int64_t offset_completed; 3976 3977 Qcow2AmendOperation last_operation; 3978 int64_t last_work_size; 3979 } Qcow2AmendHelperCBInfo; 3980 3981 static void qcow2_amend_helper_cb(BlockDriverState *bs, 3982 int64_t operation_offset, 3983 int64_t operation_work_size, void *opaque) 3984 { 3985 Qcow2AmendHelperCBInfo *info = opaque; 3986 int64_t current_work_size; 3987 int64_t projected_work_size; 3988 3989 if (info->current_operation != info->last_operation) { 3990 if (info->last_operation != QCOW2_NO_OPERATION) { 3991 info->offset_completed += info->last_work_size; 3992 info->operations_completed++; 3993 } 3994 3995 info->last_operation = info->current_operation; 3996 } 3997 3998 assert(info->total_operations > 0); 3999 assert(info->operations_completed < info->total_operations); 4000 4001 info->last_work_size = operation_work_size; 4002 4003 current_work_size = info->offset_completed + operation_work_size; 4004 4005 /* current_work_size is the total work size for (operations_completed + 1) 4006 * operations (which includes this one), so multiply it by the number of 4007 * operations not covered and divide it by the number of operations 4008 * covered to get a projection for the operations not covered */ 4009 projected_work_size = current_work_size * (info->total_operations - 4010 info->operations_completed - 1) 4011 / (info->operations_completed + 1); 4012 4013 info->original_status_cb(bs, info->offset_completed + operation_offset, 4014 current_work_size + projected_work_size, 4015 info->original_cb_opaque); 4016 } 4017 4018 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4019 BlockDriverAmendStatusCB *status_cb, 4020 void *cb_opaque) 4021 { 4022 BDRVQcow2State *s = bs->opaque; 4023 int old_version = s->qcow_version, new_version = old_version; 4024 uint64_t new_size = 0; 4025 const char *backing_file = NULL, *backing_format = NULL; 4026 bool lazy_refcounts = s->use_lazy_refcounts; 4027 const char *compat = NULL; 4028 uint64_t cluster_size = s->cluster_size; 4029 bool encrypt; 4030 int encformat; 4031 int refcount_bits = s->refcount_bits; 4032 Error *local_err = NULL; 4033 int ret; 4034 QemuOptDesc *desc = opts->list->desc; 4035 Qcow2AmendHelperCBInfo helper_cb_info; 4036 4037 while (desc && desc->name) { 4038 if (!qemu_opt_find(opts, desc->name)) { 4039 /* only change explicitly defined options */ 4040 desc++; 4041 continue; 4042 } 4043 4044 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4045 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4046 if (!compat) { 4047 /* preserve default */ 4048 } else if (!strcmp(compat, "0.10")) { 4049 new_version = 2; 4050 } else if (!strcmp(compat, "1.1")) { 4051 new_version = 3; 4052 } else { 4053 error_report("Unknown compatibility level %s", compat); 4054 return -EINVAL; 4055 } 4056 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4057 error_report("Cannot change preallocation mode"); 4058 return -ENOTSUP; 4059 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4060 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4061 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4062 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4063 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4064 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4065 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4066 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4067 !!s->crypto); 4068 4069 if (encrypt != !!s->crypto) { 4070 error_report("Changing the encryption flag is not supported"); 4071 return -ENOTSUP; 4072 } 4073 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4074 encformat = qcow2_crypt_method_from_format( 4075 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4076 4077 if (encformat != s->crypt_method_header) { 4078 error_report("Changing the encryption format is not supported"); 4079 return -ENOTSUP; 4080 } 4081 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4082 error_report("Changing the encryption parameters is not supported"); 4083 return -ENOTSUP; 4084 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4085 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4086 cluster_size); 4087 if (cluster_size != s->cluster_size) { 4088 error_report("Changing the cluster size is not supported"); 4089 return -ENOTSUP; 4090 } 4091 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4092 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4093 lazy_refcounts); 4094 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4095 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4096 refcount_bits); 4097 4098 if (refcount_bits <= 0 || refcount_bits > 64 || 4099 !is_power_of_2(refcount_bits)) 4100 { 4101 error_report("Refcount width must be a power of two and may " 4102 "not exceed 64 bits"); 4103 return -EINVAL; 4104 } 4105 } else { 4106 /* if this point is reached, this probably means a new option was 4107 * added without having it covered here */ 4108 abort(); 4109 } 4110 4111 desc++; 4112 } 4113 4114 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4115 .original_status_cb = status_cb, 4116 .original_cb_opaque = cb_opaque, 4117 .total_operations = (new_version < old_version) 4118 + (s->refcount_bits != refcount_bits) 4119 }; 4120 4121 /* Upgrade first (some features may require compat=1.1) */ 4122 if (new_version > old_version) { 4123 s->qcow_version = new_version; 4124 ret = qcow2_update_header(bs); 4125 if (ret < 0) { 4126 s->qcow_version = old_version; 4127 return ret; 4128 } 4129 } 4130 4131 if (s->refcount_bits != refcount_bits) { 4132 int refcount_order = ctz32(refcount_bits); 4133 4134 if (new_version < 3 && refcount_bits != 16) { 4135 error_report("Different refcount widths than 16 bits require " 4136 "compatibility level 1.1 or above (use compat=1.1 or " 4137 "greater)"); 4138 return -EINVAL; 4139 } 4140 4141 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4142 ret = qcow2_change_refcount_order(bs, refcount_order, 4143 &qcow2_amend_helper_cb, 4144 &helper_cb_info, &local_err); 4145 if (ret < 0) { 4146 error_report_err(local_err); 4147 return ret; 4148 } 4149 } 4150 4151 if (backing_file || backing_format) { 4152 ret = qcow2_change_backing_file(bs, 4153 backing_file ?: s->image_backing_file, 4154 backing_format ?: s->image_backing_format); 4155 if (ret < 0) { 4156 return ret; 4157 } 4158 } 4159 4160 if (s->use_lazy_refcounts != lazy_refcounts) { 4161 if (lazy_refcounts) { 4162 if (new_version < 3) { 4163 error_report("Lazy refcounts only supported with compatibility " 4164 "level 1.1 and above (use compat=1.1 or greater)"); 4165 return -EINVAL; 4166 } 4167 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4168 ret = qcow2_update_header(bs); 4169 if (ret < 0) { 4170 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4171 return ret; 4172 } 4173 s->use_lazy_refcounts = true; 4174 } else { 4175 /* make image clean first */ 4176 ret = qcow2_mark_clean(bs); 4177 if (ret < 0) { 4178 return ret; 4179 } 4180 /* now disallow lazy refcounts */ 4181 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4182 ret = qcow2_update_header(bs); 4183 if (ret < 0) { 4184 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4185 return ret; 4186 } 4187 s->use_lazy_refcounts = false; 4188 } 4189 } 4190 4191 if (new_size) { 4192 BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); 4193 ret = blk_insert_bs(blk, bs, &local_err); 4194 if (ret < 0) { 4195 error_report_err(local_err); 4196 blk_unref(blk); 4197 return ret; 4198 } 4199 4200 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, &local_err); 4201 blk_unref(blk); 4202 if (ret < 0) { 4203 error_report_err(local_err); 4204 return ret; 4205 } 4206 } 4207 4208 /* Downgrade last (so unsupported features can be removed before) */ 4209 if (new_version < old_version) { 4210 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 4211 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 4212 &helper_cb_info); 4213 if (ret < 0) { 4214 return ret; 4215 } 4216 } 4217 4218 return 0; 4219 } 4220 4221 /* 4222 * If offset or size are negative, respectively, they will not be included in 4223 * the BLOCK_IMAGE_CORRUPTED event emitted. 4224 * fatal will be ignored for read-only BDS; corruptions found there will always 4225 * be considered non-fatal. 4226 */ 4227 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 4228 int64_t size, const char *message_format, ...) 4229 { 4230 BDRVQcow2State *s = bs->opaque; 4231 const char *node_name; 4232 char *message; 4233 va_list ap; 4234 4235 fatal = fatal && !bs->read_only; 4236 4237 if (s->signaled_corruption && 4238 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 4239 { 4240 return; 4241 } 4242 4243 va_start(ap, message_format); 4244 message = g_strdup_vprintf(message_format, ap); 4245 va_end(ap); 4246 4247 if (fatal) { 4248 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 4249 "corruption events will be suppressed\n", message); 4250 } else { 4251 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 4252 "corruption events will be suppressed\n", message); 4253 } 4254 4255 node_name = bdrv_get_node_name(bs); 4256 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 4257 *node_name != '\0', node_name, 4258 message, offset >= 0, offset, 4259 size >= 0, size, 4260 fatal, &error_abort); 4261 g_free(message); 4262 4263 if (fatal) { 4264 qcow2_mark_corrupt(bs); 4265 bs->drv = NULL; /* make BDS unusable */ 4266 } 4267 4268 s->signaled_corruption = true; 4269 } 4270 4271 static QemuOptsList qcow2_create_opts = { 4272 .name = "qcow2-create-opts", 4273 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 4274 .desc = { 4275 { 4276 .name = BLOCK_OPT_SIZE, 4277 .type = QEMU_OPT_SIZE, 4278 .help = "Virtual disk size" 4279 }, 4280 { 4281 .name = BLOCK_OPT_COMPAT_LEVEL, 4282 .type = QEMU_OPT_STRING, 4283 .help = "Compatibility level (0.10 or 1.1)" 4284 }, 4285 { 4286 .name = BLOCK_OPT_BACKING_FILE, 4287 .type = QEMU_OPT_STRING, 4288 .help = "File name of a base image" 4289 }, 4290 { 4291 .name = BLOCK_OPT_BACKING_FMT, 4292 .type = QEMU_OPT_STRING, 4293 .help = "Image format of the base image" 4294 }, 4295 { 4296 .name = BLOCK_OPT_ENCRYPT, 4297 .type = QEMU_OPT_BOOL, 4298 .help = "Encrypt the image with format 'aes'. (Deprecated " 4299 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 4300 }, 4301 { 4302 .name = BLOCK_OPT_ENCRYPT_FORMAT, 4303 .type = QEMU_OPT_STRING, 4304 .help = "Encrypt the image, format choices: 'aes', 'luks'", 4305 }, 4306 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 4307 "ID of secret providing qcow AES key or LUKS passphrase"), 4308 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 4309 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 4310 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 4311 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 4312 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 4313 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 4314 { 4315 .name = BLOCK_OPT_CLUSTER_SIZE, 4316 .type = QEMU_OPT_SIZE, 4317 .help = "qcow2 cluster size", 4318 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 4319 }, 4320 { 4321 .name = BLOCK_OPT_PREALLOC, 4322 .type = QEMU_OPT_STRING, 4323 .help = "Preallocation mode (allowed values: off, metadata, " 4324 "falloc, full)" 4325 }, 4326 { 4327 .name = BLOCK_OPT_LAZY_REFCOUNTS, 4328 .type = QEMU_OPT_BOOL, 4329 .help = "Postpone refcount updates", 4330 .def_value_str = "off" 4331 }, 4332 { 4333 .name = BLOCK_OPT_REFCOUNT_BITS, 4334 .type = QEMU_OPT_NUMBER, 4335 .help = "Width of a reference count entry in bits", 4336 .def_value_str = "16" 4337 }, 4338 { /* end of list */ } 4339 } 4340 }; 4341 4342 BlockDriver bdrv_qcow2 = { 4343 .format_name = "qcow2", 4344 .instance_size = sizeof(BDRVQcow2State), 4345 .bdrv_probe = qcow2_probe, 4346 .bdrv_open = qcow2_open, 4347 .bdrv_close = qcow2_close, 4348 .bdrv_reopen_prepare = qcow2_reopen_prepare, 4349 .bdrv_reopen_commit = qcow2_reopen_commit, 4350 .bdrv_reopen_abort = qcow2_reopen_abort, 4351 .bdrv_join_options = qcow2_join_options, 4352 .bdrv_child_perm = bdrv_format_default_perms, 4353 .bdrv_create = qcow2_create, 4354 .bdrv_has_zero_init = bdrv_has_zero_init_1, 4355 .bdrv_co_get_block_status = qcow2_co_get_block_status, 4356 4357 .bdrv_co_preadv = qcow2_co_preadv, 4358 .bdrv_co_pwritev = qcow2_co_pwritev, 4359 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 4360 4361 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 4362 .bdrv_co_pdiscard = qcow2_co_pdiscard, 4363 .bdrv_truncate = qcow2_truncate, 4364 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 4365 .bdrv_make_empty = qcow2_make_empty, 4366 4367 .bdrv_snapshot_create = qcow2_snapshot_create, 4368 .bdrv_snapshot_goto = qcow2_snapshot_goto, 4369 .bdrv_snapshot_delete = qcow2_snapshot_delete, 4370 .bdrv_snapshot_list = qcow2_snapshot_list, 4371 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 4372 .bdrv_measure = qcow2_measure, 4373 .bdrv_get_info = qcow2_get_info, 4374 .bdrv_get_specific_info = qcow2_get_specific_info, 4375 4376 .bdrv_save_vmstate = qcow2_save_vmstate, 4377 .bdrv_load_vmstate = qcow2_load_vmstate, 4378 4379 .supports_backing = true, 4380 .bdrv_change_backing_file = qcow2_change_backing_file, 4381 4382 .bdrv_refresh_limits = qcow2_refresh_limits, 4383 .bdrv_invalidate_cache = qcow2_invalidate_cache, 4384 .bdrv_inactivate = qcow2_inactivate, 4385 4386 .create_opts = &qcow2_create_opts, 4387 .bdrv_check = qcow2_check, 4388 .bdrv_amend_options = qcow2_amend_options, 4389 4390 .bdrv_detach_aio_context = qcow2_detach_aio_context, 4391 .bdrv_attach_aio_context = qcow2_attach_aio_context, 4392 4393 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 4394 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 4395 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 4396 }; 4397 4398 static void bdrv_qcow2_init(void) 4399 { 4400 bdrv_register(&bdrv_qcow2); 4401 } 4402 4403 block_init(bdrv_qcow2_init); 4404