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 "block/qdict.h" 28 #include "sysemu/block-backend.h" 29 #include "qemu/module.h" 30 #include <zlib.h> 31 #include "qcow2.h" 32 #include "qemu/error-report.h" 33 #include "qapi/error.h" 34 #include "qapi/qapi-events-block-core.h" 35 #include "qapi/qmp/qdict.h" 36 #include "qapi/qmp/qstring.h" 37 #include "trace.h" 38 #include "qemu/option_int.h" 39 #include "qemu/cutils.h" 40 #include "qemu/bswap.h" 41 #include "qapi/qobject-input-visitor.h" 42 #include "qapi/qapi-visit-block-core.h" 43 #include "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 = qcow2_flush_caches(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 = qcow2_flush_caches(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 coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, 547 BdrvCheckResult *result, 548 BdrvCheckMode fix) 549 { 550 int ret = qcow2_check_refcounts(bs, result, fix); 551 if (ret < 0) { 552 return ret; 553 } 554 555 if (fix && result->check_errors == 0 && result->corruptions == 0) { 556 ret = qcow2_mark_clean(bs); 557 if (ret < 0) { 558 return ret; 559 } 560 return qcow2_mark_consistent(bs); 561 } 562 return ret; 563 } 564 565 static int coroutine_fn qcow2_co_check(BlockDriverState *bs, 566 BdrvCheckResult *result, 567 BdrvCheckMode fix) 568 { 569 BDRVQcow2State *s = bs->opaque; 570 int ret; 571 572 qemu_co_mutex_lock(&s->lock); 573 ret = qcow2_co_check_locked(bs, result, fix); 574 qemu_co_mutex_unlock(&s->lock); 575 return ret; 576 } 577 578 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, 579 uint64_t entries, size_t entry_len, 580 int64_t max_size_bytes, const char *table_name, 581 Error **errp) 582 { 583 BDRVQcow2State *s = bs->opaque; 584 585 if (entries > max_size_bytes / entry_len) { 586 error_setg(errp, "%s too large", table_name); 587 return -EFBIG; 588 } 589 590 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 591 * because values will be passed to qemu functions taking int64_t. */ 592 if ((INT64_MAX - entries * entry_len < offset) || 593 (offset_into_cluster(s, offset) != 0)) { 594 error_setg(errp, "%s offset invalid", table_name); 595 return -EINVAL; 596 } 597 598 return 0; 599 } 600 601 static QemuOptsList qcow2_runtime_opts = { 602 .name = "qcow2", 603 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 604 .desc = { 605 { 606 .name = QCOW2_OPT_LAZY_REFCOUNTS, 607 .type = QEMU_OPT_BOOL, 608 .help = "Postpone refcount updates", 609 }, 610 { 611 .name = QCOW2_OPT_DISCARD_REQUEST, 612 .type = QEMU_OPT_BOOL, 613 .help = "Pass guest discard requests to the layer below", 614 }, 615 { 616 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 617 .type = QEMU_OPT_BOOL, 618 .help = "Generate discard requests when snapshot related space " 619 "is freed", 620 }, 621 { 622 .name = QCOW2_OPT_DISCARD_OTHER, 623 .type = QEMU_OPT_BOOL, 624 .help = "Generate discard requests when other clusters are freed", 625 }, 626 { 627 .name = QCOW2_OPT_OVERLAP, 628 .type = QEMU_OPT_STRING, 629 .help = "Selects which overlap checks to perform from a range of " 630 "templates (none, constant, cached, all)", 631 }, 632 { 633 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 634 .type = QEMU_OPT_STRING, 635 .help = "Selects which overlap checks to perform from a range of " 636 "templates (none, constant, cached, all)", 637 }, 638 { 639 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 640 .type = QEMU_OPT_BOOL, 641 .help = "Check for unintended writes into the main qcow2 header", 642 }, 643 { 644 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 645 .type = QEMU_OPT_BOOL, 646 .help = "Check for unintended writes into the active L1 table", 647 }, 648 { 649 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 650 .type = QEMU_OPT_BOOL, 651 .help = "Check for unintended writes into an active L2 table", 652 }, 653 { 654 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 655 .type = QEMU_OPT_BOOL, 656 .help = "Check for unintended writes into the refcount table", 657 }, 658 { 659 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 660 .type = QEMU_OPT_BOOL, 661 .help = "Check for unintended writes into a refcount block", 662 }, 663 { 664 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 665 .type = QEMU_OPT_BOOL, 666 .help = "Check for unintended writes into the snapshot table", 667 }, 668 { 669 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 670 .type = QEMU_OPT_BOOL, 671 .help = "Check for unintended writes into an inactive L1 table", 672 }, 673 { 674 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 675 .type = QEMU_OPT_BOOL, 676 .help = "Check for unintended writes into an inactive L2 table", 677 }, 678 { 679 .name = QCOW2_OPT_CACHE_SIZE, 680 .type = QEMU_OPT_SIZE, 681 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 682 "cache size", 683 }, 684 { 685 .name = QCOW2_OPT_L2_CACHE_SIZE, 686 .type = QEMU_OPT_SIZE, 687 .help = "Maximum L2 table cache size", 688 }, 689 { 690 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 691 .type = QEMU_OPT_SIZE, 692 .help = "Size of each entry in the L2 cache", 693 }, 694 { 695 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 696 .type = QEMU_OPT_SIZE, 697 .help = "Maximum refcount block cache size", 698 }, 699 { 700 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 701 .type = QEMU_OPT_NUMBER, 702 .help = "Clean unused cache entries after this time (in seconds)", 703 }, 704 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 705 "ID of secret providing qcow2 AES key or LUKS passphrase"), 706 { /* end of list */ } 707 }, 708 }; 709 710 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 711 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 712 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 713 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 714 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 715 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 716 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 717 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 718 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 719 }; 720 721 static void cache_clean_timer_cb(void *opaque) 722 { 723 BlockDriverState *bs = opaque; 724 BDRVQcow2State *s = bs->opaque; 725 qcow2_cache_clean_unused(s->l2_table_cache); 726 qcow2_cache_clean_unused(s->refcount_block_cache); 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 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 732 { 733 BDRVQcow2State *s = bs->opaque; 734 if (s->cache_clean_interval > 0) { 735 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 736 SCALE_MS, cache_clean_timer_cb, 737 bs); 738 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 739 (int64_t) s->cache_clean_interval * 1000); 740 } 741 } 742 743 static void cache_clean_timer_del(BlockDriverState *bs) 744 { 745 BDRVQcow2State *s = bs->opaque; 746 if (s->cache_clean_timer) { 747 timer_del(s->cache_clean_timer); 748 timer_free(s->cache_clean_timer); 749 s->cache_clean_timer = NULL; 750 } 751 } 752 753 static void qcow2_detach_aio_context(BlockDriverState *bs) 754 { 755 cache_clean_timer_del(bs); 756 } 757 758 static void qcow2_attach_aio_context(BlockDriverState *bs, 759 AioContext *new_context) 760 { 761 cache_clean_timer_init(bs, new_context); 762 } 763 764 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 765 uint64_t *l2_cache_size, 766 uint64_t *l2_cache_entry_size, 767 uint64_t *refcount_cache_size, Error **errp) 768 { 769 BDRVQcow2State *s = bs->opaque; 770 uint64_t combined_cache_size; 771 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 772 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; 773 774 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 775 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 776 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 777 778 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 779 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 780 *refcount_cache_size = qemu_opt_get_size(opts, 781 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 782 783 *l2_cache_entry_size = qemu_opt_get_size( 784 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 785 786 if (combined_cache_size_set) { 787 if (l2_cache_size_set && refcount_cache_size_set) { 788 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 789 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 790 "the same time"); 791 return; 792 } else if (*l2_cache_size > combined_cache_size) { 793 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 794 QCOW2_OPT_CACHE_SIZE); 795 return; 796 } else if (*refcount_cache_size > combined_cache_size) { 797 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 798 QCOW2_OPT_CACHE_SIZE); 799 return; 800 } 801 802 if (l2_cache_size_set) { 803 *refcount_cache_size = combined_cache_size - *l2_cache_size; 804 } else if (refcount_cache_size_set) { 805 *l2_cache_size = combined_cache_size - *refcount_cache_size; 806 } else { 807 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; 808 uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8); 809 810 /* Assign as much memory as possible to the L2 cache, and 811 * use the remainder for the refcount cache */ 812 if (combined_cache_size >= max_l2_cache + min_refcount_cache) { 813 *l2_cache_size = max_l2_cache; 814 *refcount_cache_size = combined_cache_size - *l2_cache_size; 815 } else { 816 *refcount_cache_size = 817 MIN(combined_cache_size, min_refcount_cache); 818 *l2_cache_size = combined_cache_size - *refcount_cache_size; 819 } 820 } 821 } else { 822 if (!l2_cache_size_set) { 823 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 824 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 825 * s->cluster_size); 826 } 827 if (!refcount_cache_size_set) { 828 *refcount_cache_size = min_refcount_cache; 829 } 830 } 831 832 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 833 *l2_cache_entry_size > s->cluster_size || 834 !is_power_of_2(*l2_cache_entry_size)) { 835 error_setg(errp, "L2 cache entry size must be a power of two " 836 "between %d and the cluster size (%d)", 837 1 << MIN_CLUSTER_BITS, s->cluster_size); 838 return; 839 } 840 } 841 842 typedef struct Qcow2ReopenState { 843 Qcow2Cache *l2_table_cache; 844 Qcow2Cache *refcount_block_cache; 845 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 846 bool use_lazy_refcounts; 847 int overlap_check; 848 bool discard_passthrough[QCOW2_DISCARD_MAX]; 849 uint64_t cache_clean_interval; 850 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 851 } Qcow2ReopenState; 852 853 static int qcow2_update_options_prepare(BlockDriverState *bs, 854 Qcow2ReopenState *r, 855 QDict *options, int flags, 856 Error **errp) 857 { 858 BDRVQcow2State *s = bs->opaque; 859 QemuOpts *opts = NULL; 860 const char *opt_overlap_check, *opt_overlap_check_template; 861 int overlap_check_template = 0; 862 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 863 int i; 864 const char *encryptfmt; 865 QDict *encryptopts = NULL; 866 Error *local_err = NULL; 867 int ret; 868 869 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 870 encryptfmt = qdict_get_try_str(encryptopts, "format"); 871 872 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 873 qemu_opts_absorb_qdict(opts, options, &local_err); 874 if (local_err) { 875 error_propagate(errp, local_err); 876 ret = -EINVAL; 877 goto fail; 878 } 879 880 /* get L2 table/refcount block cache size from command line options */ 881 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 882 &refcount_cache_size, &local_err); 883 if (local_err) { 884 error_propagate(errp, local_err); 885 ret = -EINVAL; 886 goto fail; 887 } 888 889 l2_cache_size /= l2_cache_entry_size; 890 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 891 l2_cache_size = MIN_L2_CACHE_SIZE; 892 } 893 if (l2_cache_size > INT_MAX) { 894 error_setg(errp, "L2 cache size too big"); 895 ret = -EINVAL; 896 goto fail; 897 } 898 899 refcount_cache_size /= s->cluster_size; 900 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 901 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 902 } 903 if (refcount_cache_size > INT_MAX) { 904 error_setg(errp, "Refcount cache size too big"); 905 ret = -EINVAL; 906 goto fail; 907 } 908 909 /* alloc new L2 table/refcount block cache, flush old one */ 910 if (s->l2_table_cache) { 911 ret = qcow2_cache_flush(bs, s->l2_table_cache); 912 if (ret) { 913 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 914 goto fail; 915 } 916 } 917 918 if (s->refcount_block_cache) { 919 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 920 if (ret) { 921 error_setg_errno(errp, -ret, 922 "Failed to flush the refcount block cache"); 923 goto fail; 924 } 925 } 926 927 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 928 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 929 l2_cache_entry_size); 930 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 931 s->cluster_size); 932 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 933 error_setg(errp, "Could not allocate metadata caches"); 934 ret = -ENOMEM; 935 goto fail; 936 } 937 938 /* New interval for cache cleanup timer */ 939 r->cache_clean_interval = 940 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 941 s->cache_clean_interval); 942 #ifndef CONFIG_LINUX 943 if (r->cache_clean_interval != 0) { 944 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 945 " not supported on this host"); 946 ret = -EINVAL; 947 goto fail; 948 } 949 #endif 950 if (r->cache_clean_interval > UINT_MAX) { 951 error_setg(errp, "Cache clean interval too big"); 952 ret = -EINVAL; 953 goto fail; 954 } 955 956 /* lazy-refcounts; flush if going from enabled to disabled */ 957 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 958 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 959 if (r->use_lazy_refcounts && s->qcow_version < 3) { 960 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 961 "qemu 1.1 compatibility level"); 962 ret = -EINVAL; 963 goto fail; 964 } 965 966 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 967 ret = qcow2_mark_clean(bs); 968 if (ret < 0) { 969 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 970 goto fail; 971 } 972 } 973 974 /* Overlap check options */ 975 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 976 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 977 if (opt_overlap_check_template && opt_overlap_check && 978 strcmp(opt_overlap_check_template, opt_overlap_check)) 979 { 980 error_setg(errp, "Conflicting values for qcow2 options '" 981 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 982 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 983 ret = -EINVAL; 984 goto fail; 985 } 986 if (!opt_overlap_check) { 987 opt_overlap_check = opt_overlap_check_template ?: "cached"; 988 } 989 990 if (!strcmp(opt_overlap_check, "none")) { 991 overlap_check_template = 0; 992 } else if (!strcmp(opt_overlap_check, "constant")) { 993 overlap_check_template = QCOW2_OL_CONSTANT; 994 } else if (!strcmp(opt_overlap_check, "cached")) { 995 overlap_check_template = QCOW2_OL_CACHED; 996 } else if (!strcmp(opt_overlap_check, "all")) { 997 overlap_check_template = QCOW2_OL_ALL; 998 } else { 999 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1000 "'overlap-check'. Allowed are any of the following: " 1001 "none, constant, cached, all", opt_overlap_check); 1002 ret = -EINVAL; 1003 goto fail; 1004 } 1005 1006 r->overlap_check = 0; 1007 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1008 /* overlap-check defines a template bitmask, but every flag may be 1009 * overwritten through the associated boolean option */ 1010 r->overlap_check |= 1011 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1012 overlap_check_template & (1 << i)) << i; 1013 } 1014 1015 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 1016 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1017 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1018 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1019 flags & BDRV_O_UNMAP); 1020 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1021 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1022 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1023 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1024 1025 switch (s->crypt_method_header) { 1026 case QCOW_CRYPT_NONE: 1027 if (encryptfmt) { 1028 error_setg(errp, "No encryption in image header, but options " 1029 "specified format '%s'", encryptfmt); 1030 ret = -EINVAL; 1031 goto fail; 1032 } 1033 break; 1034 1035 case QCOW_CRYPT_AES: 1036 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1037 error_setg(errp, 1038 "Header reported 'aes' encryption format but " 1039 "options specify '%s'", encryptfmt); 1040 ret = -EINVAL; 1041 goto fail; 1042 } 1043 qdict_del(encryptopts, "format"); 1044 r->crypto_opts = block_crypto_open_opts_init( 1045 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 1046 break; 1047 1048 case QCOW_CRYPT_LUKS: 1049 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1050 error_setg(errp, 1051 "Header reported 'luks' encryption format but " 1052 "options specify '%s'", encryptfmt); 1053 ret = -EINVAL; 1054 goto fail; 1055 } 1056 qdict_del(encryptopts, "format"); 1057 r->crypto_opts = block_crypto_open_opts_init( 1058 Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); 1059 break; 1060 1061 default: 1062 error_setg(errp, "Unsupported encryption method %d", 1063 s->crypt_method_header); 1064 break; 1065 } 1066 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1067 ret = -EINVAL; 1068 goto fail; 1069 } 1070 1071 ret = 0; 1072 fail: 1073 qobject_unref(encryptopts); 1074 qemu_opts_del(opts); 1075 opts = NULL; 1076 return ret; 1077 } 1078 1079 static void qcow2_update_options_commit(BlockDriverState *bs, 1080 Qcow2ReopenState *r) 1081 { 1082 BDRVQcow2State *s = bs->opaque; 1083 int i; 1084 1085 if (s->l2_table_cache) { 1086 qcow2_cache_destroy(s->l2_table_cache); 1087 } 1088 if (s->refcount_block_cache) { 1089 qcow2_cache_destroy(s->refcount_block_cache); 1090 } 1091 s->l2_table_cache = r->l2_table_cache; 1092 s->refcount_block_cache = r->refcount_block_cache; 1093 s->l2_slice_size = r->l2_slice_size; 1094 1095 s->overlap_check = r->overlap_check; 1096 s->use_lazy_refcounts = r->use_lazy_refcounts; 1097 1098 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1099 s->discard_passthrough[i] = r->discard_passthrough[i]; 1100 } 1101 1102 if (s->cache_clean_interval != r->cache_clean_interval) { 1103 cache_clean_timer_del(bs); 1104 s->cache_clean_interval = r->cache_clean_interval; 1105 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1106 } 1107 1108 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1109 s->crypto_opts = r->crypto_opts; 1110 } 1111 1112 static void qcow2_update_options_abort(BlockDriverState *bs, 1113 Qcow2ReopenState *r) 1114 { 1115 if (r->l2_table_cache) { 1116 qcow2_cache_destroy(r->l2_table_cache); 1117 } 1118 if (r->refcount_block_cache) { 1119 qcow2_cache_destroy(r->refcount_block_cache); 1120 } 1121 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1122 } 1123 1124 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1125 int flags, Error **errp) 1126 { 1127 Qcow2ReopenState r = {}; 1128 int ret; 1129 1130 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1131 if (ret >= 0) { 1132 qcow2_update_options_commit(bs, &r); 1133 } else { 1134 qcow2_update_options_abort(bs, &r); 1135 } 1136 1137 return ret; 1138 } 1139 1140 /* Called with s->lock held. */ 1141 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, 1142 int flags, Error **errp) 1143 { 1144 BDRVQcow2State *s = bs->opaque; 1145 unsigned int len, i; 1146 int ret = 0; 1147 QCowHeader header; 1148 Error *local_err = NULL; 1149 uint64_t ext_end; 1150 uint64_t l1_vm_state_index; 1151 bool update_header = false; 1152 bool header_updated = false; 1153 1154 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1155 if (ret < 0) { 1156 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1157 goto fail; 1158 } 1159 be32_to_cpus(&header.magic); 1160 be32_to_cpus(&header.version); 1161 be64_to_cpus(&header.backing_file_offset); 1162 be32_to_cpus(&header.backing_file_size); 1163 be64_to_cpus(&header.size); 1164 be32_to_cpus(&header.cluster_bits); 1165 be32_to_cpus(&header.crypt_method); 1166 be64_to_cpus(&header.l1_table_offset); 1167 be32_to_cpus(&header.l1_size); 1168 be64_to_cpus(&header.refcount_table_offset); 1169 be32_to_cpus(&header.refcount_table_clusters); 1170 be64_to_cpus(&header.snapshots_offset); 1171 be32_to_cpus(&header.nb_snapshots); 1172 1173 if (header.magic != QCOW_MAGIC) { 1174 error_setg(errp, "Image is not in qcow2 format"); 1175 ret = -EINVAL; 1176 goto fail; 1177 } 1178 if (header.version < 2 || header.version > 3) { 1179 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1180 ret = -ENOTSUP; 1181 goto fail; 1182 } 1183 1184 s->qcow_version = header.version; 1185 1186 /* Initialise cluster size */ 1187 if (header.cluster_bits < MIN_CLUSTER_BITS || 1188 header.cluster_bits > MAX_CLUSTER_BITS) { 1189 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1190 header.cluster_bits); 1191 ret = -EINVAL; 1192 goto fail; 1193 } 1194 1195 s->cluster_bits = header.cluster_bits; 1196 s->cluster_size = 1 << s->cluster_bits; 1197 s->cluster_sectors = 1 << (s->cluster_bits - BDRV_SECTOR_BITS); 1198 1199 /* Initialise version 3 header fields */ 1200 if (header.version == 2) { 1201 header.incompatible_features = 0; 1202 header.compatible_features = 0; 1203 header.autoclear_features = 0; 1204 header.refcount_order = 4; 1205 header.header_length = 72; 1206 } else { 1207 be64_to_cpus(&header.incompatible_features); 1208 be64_to_cpus(&header.compatible_features); 1209 be64_to_cpus(&header.autoclear_features); 1210 be32_to_cpus(&header.refcount_order); 1211 be32_to_cpus(&header.header_length); 1212 1213 if (header.header_length < 104) { 1214 error_setg(errp, "qcow2 header too short"); 1215 ret = -EINVAL; 1216 goto fail; 1217 } 1218 } 1219 1220 if (header.header_length > s->cluster_size) { 1221 error_setg(errp, "qcow2 header exceeds cluster size"); 1222 ret = -EINVAL; 1223 goto fail; 1224 } 1225 1226 if (header.header_length > sizeof(header)) { 1227 s->unknown_header_fields_size = header.header_length - sizeof(header); 1228 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1229 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1230 s->unknown_header_fields_size); 1231 if (ret < 0) { 1232 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1233 "fields"); 1234 goto fail; 1235 } 1236 } 1237 1238 if (header.backing_file_offset > s->cluster_size) { 1239 error_setg(errp, "Invalid backing file offset"); 1240 ret = -EINVAL; 1241 goto fail; 1242 } 1243 1244 if (header.backing_file_offset) { 1245 ext_end = header.backing_file_offset; 1246 } else { 1247 ext_end = 1 << header.cluster_bits; 1248 } 1249 1250 /* Handle feature bits */ 1251 s->incompatible_features = header.incompatible_features; 1252 s->compatible_features = header.compatible_features; 1253 s->autoclear_features = header.autoclear_features; 1254 1255 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1256 void *feature_table = NULL; 1257 qcow2_read_extensions(bs, header.header_length, ext_end, 1258 &feature_table, flags, NULL, NULL); 1259 report_unsupported_feature(errp, feature_table, 1260 s->incompatible_features & 1261 ~QCOW2_INCOMPAT_MASK); 1262 ret = -ENOTSUP; 1263 g_free(feature_table); 1264 goto fail; 1265 } 1266 1267 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1268 /* Corrupt images may not be written to unless they are being repaired 1269 */ 1270 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1271 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1272 "read/write"); 1273 ret = -EACCES; 1274 goto fail; 1275 } 1276 } 1277 1278 /* Check support for various header values */ 1279 if (header.refcount_order > 6) { 1280 error_setg(errp, "Reference count entry width too large; may not " 1281 "exceed 64 bits"); 1282 ret = -EINVAL; 1283 goto fail; 1284 } 1285 s->refcount_order = header.refcount_order; 1286 s->refcount_bits = 1 << s->refcount_order; 1287 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1288 s->refcount_max += s->refcount_max - 1; 1289 1290 s->crypt_method_header = header.crypt_method; 1291 if (s->crypt_method_header) { 1292 if (bdrv_uses_whitelist() && 1293 s->crypt_method_header == QCOW_CRYPT_AES) { 1294 error_setg(errp, 1295 "Use of AES-CBC encrypted qcow2 images is no longer " 1296 "supported in system emulators"); 1297 error_append_hint(errp, 1298 "You can use 'qemu-img convert' to convert your " 1299 "image to an alternative supported format, such " 1300 "as unencrypted qcow2, or raw with the LUKS " 1301 "format instead.\n"); 1302 ret = -ENOSYS; 1303 goto fail; 1304 } 1305 1306 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1307 s->crypt_physical_offset = false; 1308 } else { 1309 /* Assuming LUKS and any future crypt methods we 1310 * add will all use physical offsets, due to the 1311 * fact that the alternative is insecure... */ 1312 s->crypt_physical_offset = true; 1313 } 1314 1315 bs->encrypted = true; 1316 } 1317 1318 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1319 s->l2_size = 1 << s->l2_bits; 1320 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1321 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1322 s->refcount_block_size = 1 << s->refcount_block_bits; 1323 bs->total_sectors = header.size / 512; 1324 s->csize_shift = (62 - (s->cluster_bits - 8)); 1325 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1326 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1327 1328 s->refcount_table_offset = header.refcount_table_offset; 1329 s->refcount_table_size = 1330 header.refcount_table_clusters << (s->cluster_bits - 3); 1331 1332 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1333 error_setg(errp, "Image does not contain a reference count table"); 1334 ret = -EINVAL; 1335 goto fail; 1336 } 1337 1338 ret = qcow2_validate_table(bs, s->refcount_table_offset, 1339 header.refcount_table_clusters, 1340 s->cluster_size, QCOW_MAX_REFTABLE_SIZE, 1341 "Reference count table", errp); 1342 if (ret < 0) { 1343 goto fail; 1344 } 1345 1346 /* The total size in bytes of the snapshot table is checked in 1347 * qcow2_read_snapshots() because the size of each snapshot is 1348 * variable and we don't know it yet. 1349 * Here we only check the offset and number of snapshots. */ 1350 ret = qcow2_validate_table(bs, header.snapshots_offset, 1351 header.nb_snapshots, 1352 sizeof(QCowSnapshotHeader), 1353 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, 1354 "Snapshot table", errp); 1355 if (ret < 0) { 1356 goto fail; 1357 } 1358 1359 /* read the level 1 table */ 1360 ret = qcow2_validate_table(bs, header.l1_table_offset, 1361 header.l1_size, sizeof(uint64_t), 1362 QCOW_MAX_L1_SIZE, "Active L1 table", errp); 1363 if (ret < 0) { 1364 goto fail; 1365 } 1366 s->l1_size = header.l1_size; 1367 s->l1_table_offset = header.l1_table_offset; 1368 1369 l1_vm_state_index = size_to_l1(s, header.size); 1370 if (l1_vm_state_index > INT_MAX) { 1371 error_setg(errp, "Image is too big"); 1372 ret = -EFBIG; 1373 goto fail; 1374 } 1375 s->l1_vm_state_index = l1_vm_state_index; 1376 1377 /* the L1 table must contain at least enough entries to put 1378 header.size bytes */ 1379 if (s->l1_size < s->l1_vm_state_index) { 1380 error_setg(errp, "L1 table is too small"); 1381 ret = -EINVAL; 1382 goto fail; 1383 } 1384 1385 if (s->l1_size > 0) { 1386 s->l1_table = qemu_try_blockalign(bs->file->bs, 1387 ROUND_UP(s->l1_size * sizeof(uint64_t), 512)); 1388 if (s->l1_table == NULL) { 1389 error_setg(errp, "Could not allocate L1 table"); 1390 ret = -ENOMEM; 1391 goto fail; 1392 } 1393 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1394 s->l1_size * sizeof(uint64_t)); 1395 if (ret < 0) { 1396 error_setg_errno(errp, -ret, "Could not read L1 table"); 1397 goto fail; 1398 } 1399 for(i = 0;i < s->l1_size; i++) { 1400 be64_to_cpus(&s->l1_table[i]); 1401 } 1402 } 1403 1404 /* Parse driver-specific options */ 1405 ret = qcow2_update_options(bs, options, flags, errp); 1406 if (ret < 0) { 1407 goto fail; 1408 } 1409 1410 s->cluster_cache_offset = -1; 1411 s->flags = flags; 1412 1413 ret = qcow2_refcount_init(bs); 1414 if (ret != 0) { 1415 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1416 goto fail; 1417 } 1418 1419 QLIST_INIT(&s->cluster_allocs); 1420 QTAILQ_INIT(&s->discards); 1421 1422 /* read qcow2 extensions */ 1423 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1424 flags, &update_header, &local_err)) { 1425 error_propagate(errp, local_err); 1426 ret = -EINVAL; 1427 goto fail; 1428 } 1429 1430 /* qcow2_read_extension may have set up the crypto context 1431 * if the crypt method needs a header region, some methods 1432 * don't need header extensions, so must check here 1433 */ 1434 if (s->crypt_method_header && !s->crypto) { 1435 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1436 unsigned int cflags = 0; 1437 if (flags & BDRV_O_NO_IO) { 1438 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1439 } 1440 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1441 NULL, NULL, cflags, errp); 1442 if (!s->crypto) { 1443 ret = -EINVAL; 1444 goto fail; 1445 } 1446 } else if (!(flags & BDRV_O_NO_IO)) { 1447 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1448 s->crypt_method_header); 1449 ret = -EINVAL; 1450 goto fail; 1451 } 1452 } 1453 1454 /* read the backing file name */ 1455 if (header.backing_file_offset != 0) { 1456 len = header.backing_file_size; 1457 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1458 len >= sizeof(bs->backing_file)) { 1459 error_setg(errp, "Backing file name too long"); 1460 ret = -EINVAL; 1461 goto fail; 1462 } 1463 ret = bdrv_pread(bs->file, header.backing_file_offset, 1464 bs->backing_file, len); 1465 if (ret < 0) { 1466 error_setg_errno(errp, -ret, "Could not read backing file name"); 1467 goto fail; 1468 } 1469 bs->backing_file[len] = '\0'; 1470 s->image_backing_file = g_strdup(bs->backing_file); 1471 } 1472 1473 /* Internal snapshots */ 1474 s->snapshots_offset = header.snapshots_offset; 1475 s->nb_snapshots = header.nb_snapshots; 1476 1477 ret = qcow2_read_snapshots(bs); 1478 if (ret < 0) { 1479 error_setg_errno(errp, -ret, "Could not read snapshots"); 1480 goto fail; 1481 } 1482 1483 /* Clear unknown autoclear feature bits */ 1484 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1485 update_header = 1486 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1487 if (update_header) { 1488 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1489 } 1490 1491 if (s->dirty_bitmaps_loaded) { 1492 /* It's some kind of reopen. There are no known cases where we need to 1493 * reload bitmaps in such a situation, so it's safer to skip them. 1494 * 1495 * Moreover, if we have some readonly bitmaps and we are reopening for 1496 * rw we should reopen bitmaps correspondingly. 1497 */ 1498 if (bdrv_has_readonly_bitmaps(bs) && 1499 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) 1500 { 1501 qcow2_reopen_bitmaps_rw_hint(bs, &header_updated, &local_err); 1502 } 1503 } else { 1504 header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); 1505 s->dirty_bitmaps_loaded = true; 1506 } 1507 update_header = update_header && !header_updated; 1508 if (local_err != NULL) { 1509 error_propagate(errp, local_err); 1510 ret = -EINVAL; 1511 goto fail; 1512 } 1513 1514 if (update_header) { 1515 ret = qcow2_update_header(bs); 1516 if (ret < 0) { 1517 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1518 goto fail; 1519 } 1520 } 1521 1522 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1523 1524 /* Repair image if dirty */ 1525 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1526 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1527 BdrvCheckResult result = {0}; 1528 1529 ret = qcow2_co_check_locked(bs, &result, 1530 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1531 if (ret < 0 || result.check_errors) { 1532 if (ret >= 0) { 1533 ret = -EIO; 1534 } 1535 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1536 goto fail; 1537 } 1538 } 1539 1540 #ifdef DEBUG_ALLOC 1541 { 1542 BdrvCheckResult result = {0}; 1543 qcow2_check_refcounts(bs, &result, 0); 1544 } 1545 #endif 1546 return ret; 1547 1548 fail: 1549 g_free(s->unknown_header_fields); 1550 cleanup_unknown_header_ext(bs); 1551 qcow2_free_snapshots(bs); 1552 qcow2_refcount_close(bs); 1553 qemu_vfree(s->l1_table); 1554 /* else pre-write overlap checks in cache_destroy may crash */ 1555 s->l1_table = NULL; 1556 cache_clean_timer_del(bs); 1557 if (s->l2_table_cache) { 1558 qcow2_cache_destroy(s->l2_table_cache); 1559 } 1560 if (s->refcount_block_cache) { 1561 qcow2_cache_destroy(s->refcount_block_cache); 1562 } 1563 qcrypto_block_free(s->crypto); 1564 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1565 return ret; 1566 } 1567 1568 typedef struct QCow2OpenCo { 1569 BlockDriverState *bs; 1570 QDict *options; 1571 int flags; 1572 Error **errp; 1573 int ret; 1574 } QCow2OpenCo; 1575 1576 static void coroutine_fn qcow2_open_entry(void *opaque) 1577 { 1578 QCow2OpenCo *qoc = opaque; 1579 BDRVQcow2State *s = qoc->bs->opaque; 1580 1581 qemu_co_mutex_lock(&s->lock); 1582 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); 1583 qemu_co_mutex_unlock(&s->lock); 1584 } 1585 1586 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1587 Error **errp) 1588 { 1589 BDRVQcow2State *s = bs->opaque; 1590 QCow2OpenCo qoc = { 1591 .bs = bs, 1592 .options = options, 1593 .flags = flags, 1594 .errp = errp, 1595 .ret = -EINPROGRESS 1596 }; 1597 1598 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1599 false, errp); 1600 if (!bs->file) { 1601 return -EINVAL; 1602 } 1603 1604 /* Initialise locks */ 1605 qemu_co_mutex_init(&s->lock); 1606 1607 if (qemu_in_coroutine()) { 1608 /* From bdrv_co_create. */ 1609 qcow2_open_entry(&qoc); 1610 } else { 1611 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); 1612 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); 1613 } 1614 return qoc.ret; 1615 } 1616 1617 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1618 { 1619 BDRVQcow2State *s = bs->opaque; 1620 1621 if (bs->encrypted) { 1622 /* Encryption works on a sector granularity */ 1623 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 1624 } 1625 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1626 bs->bl.pdiscard_alignment = s->cluster_size; 1627 } 1628 1629 static int qcow2_reopen_prepare(BDRVReopenState *state, 1630 BlockReopenQueue *queue, Error **errp) 1631 { 1632 Qcow2ReopenState *r; 1633 int ret; 1634 1635 r = g_new0(Qcow2ReopenState, 1); 1636 state->opaque = r; 1637 1638 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1639 state->flags, errp); 1640 if (ret < 0) { 1641 goto fail; 1642 } 1643 1644 /* We need to write out any unwritten data if we reopen read-only. */ 1645 if ((state->flags & BDRV_O_RDWR) == 0) { 1646 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1647 if (ret < 0) { 1648 goto fail; 1649 } 1650 1651 ret = bdrv_flush(state->bs); 1652 if (ret < 0) { 1653 goto fail; 1654 } 1655 1656 ret = qcow2_mark_clean(state->bs); 1657 if (ret < 0) { 1658 goto fail; 1659 } 1660 } 1661 1662 return 0; 1663 1664 fail: 1665 qcow2_update_options_abort(state->bs, r); 1666 g_free(r); 1667 return ret; 1668 } 1669 1670 static void qcow2_reopen_commit(BDRVReopenState *state) 1671 { 1672 qcow2_update_options_commit(state->bs, state->opaque); 1673 g_free(state->opaque); 1674 } 1675 1676 static void qcow2_reopen_abort(BDRVReopenState *state) 1677 { 1678 qcow2_update_options_abort(state->bs, state->opaque); 1679 g_free(state->opaque); 1680 } 1681 1682 static void qcow2_join_options(QDict *options, QDict *old_options) 1683 { 1684 bool has_new_overlap_template = 1685 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1686 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1687 bool has_new_total_cache_size = 1688 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1689 bool has_all_cache_options; 1690 1691 /* New overlap template overrides all old overlap options */ 1692 if (has_new_overlap_template) { 1693 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1694 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1695 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1696 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1697 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1698 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1699 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1700 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1701 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1702 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1703 } 1704 1705 /* New total cache size overrides all old options */ 1706 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1707 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1708 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1709 } 1710 1711 qdict_join(options, old_options, false); 1712 1713 /* 1714 * If after merging all cache size options are set, an old total size is 1715 * overwritten. Do keep all options, however, if all three are new. The 1716 * resulting error message is what we want to happen. 1717 */ 1718 has_all_cache_options = 1719 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1720 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1721 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1722 1723 if (has_all_cache_options && !has_new_total_cache_size) { 1724 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1725 } 1726 } 1727 1728 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, 1729 bool want_zero, 1730 int64_t offset, int64_t count, 1731 int64_t *pnum, int64_t *map, 1732 BlockDriverState **file) 1733 { 1734 BDRVQcow2State *s = bs->opaque; 1735 uint64_t cluster_offset; 1736 int index_in_cluster, ret; 1737 unsigned int bytes; 1738 int status = 0; 1739 1740 bytes = MIN(INT_MAX, count); 1741 qemu_co_mutex_lock(&s->lock); 1742 ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); 1743 qemu_co_mutex_unlock(&s->lock); 1744 if (ret < 0) { 1745 return ret; 1746 } 1747 1748 *pnum = bytes; 1749 1750 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1751 !s->crypto) { 1752 index_in_cluster = offset & (s->cluster_size - 1); 1753 *map = cluster_offset | index_in_cluster; 1754 *file = bs->file->bs; 1755 status |= BDRV_BLOCK_OFFSET_VALID; 1756 } 1757 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1758 status |= BDRV_BLOCK_ZERO; 1759 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1760 status |= BDRV_BLOCK_DATA; 1761 } 1762 return status; 1763 } 1764 1765 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, 1766 QCowL2Meta **pl2meta, 1767 bool link_l2) 1768 { 1769 int ret = 0; 1770 QCowL2Meta *l2meta = *pl2meta; 1771 1772 while (l2meta != NULL) { 1773 QCowL2Meta *next; 1774 1775 if (!ret && link_l2) { 1776 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1777 if (ret) { 1778 goto out; 1779 } 1780 } 1781 1782 /* Take the request off the list of running requests */ 1783 if (l2meta->nb_clusters != 0) { 1784 QLIST_REMOVE(l2meta, next_in_flight); 1785 } 1786 1787 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1788 1789 next = l2meta->next; 1790 g_free(l2meta); 1791 l2meta = next; 1792 } 1793 out: 1794 *pl2meta = l2meta; 1795 return ret; 1796 } 1797 1798 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1799 uint64_t bytes, QEMUIOVector *qiov, 1800 int flags) 1801 { 1802 BDRVQcow2State *s = bs->opaque; 1803 int offset_in_cluster; 1804 int ret; 1805 unsigned int cur_bytes; /* number of bytes in current iteration */ 1806 uint64_t cluster_offset = 0; 1807 uint64_t bytes_done = 0; 1808 QEMUIOVector hd_qiov; 1809 uint8_t *cluster_data = NULL; 1810 1811 qemu_iovec_init(&hd_qiov, qiov->niov); 1812 1813 qemu_co_mutex_lock(&s->lock); 1814 1815 while (bytes != 0) { 1816 1817 /* prepare next request */ 1818 cur_bytes = MIN(bytes, INT_MAX); 1819 if (s->crypto) { 1820 cur_bytes = MIN(cur_bytes, 1821 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1822 } 1823 1824 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1825 if (ret < 0) { 1826 goto fail; 1827 } 1828 1829 offset_in_cluster = offset_into_cluster(s, offset); 1830 1831 qemu_iovec_reset(&hd_qiov); 1832 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1833 1834 switch (ret) { 1835 case QCOW2_CLUSTER_UNALLOCATED: 1836 1837 if (bs->backing) { 1838 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1839 qemu_co_mutex_unlock(&s->lock); 1840 ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, 1841 &hd_qiov, 0); 1842 qemu_co_mutex_lock(&s->lock); 1843 if (ret < 0) { 1844 goto fail; 1845 } 1846 } else { 1847 /* Note: in this case, no need to wait */ 1848 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1849 } 1850 break; 1851 1852 case QCOW2_CLUSTER_ZERO_PLAIN: 1853 case QCOW2_CLUSTER_ZERO_ALLOC: 1854 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1855 break; 1856 1857 case QCOW2_CLUSTER_COMPRESSED: 1858 /* add AIO support for compressed blocks ? */ 1859 ret = qcow2_decompress_cluster(bs, cluster_offset); 1860 if (ret < 0) { 1861 goto fail; 1862 } 1863 1864 qemu_iovec_from_buf(&hd_qiov, 0, 1865 s->cluster_cache + offset_in_cluster, 1866 cur_bytes); 1867 break; 1868 1869 case QCOW2_CLUSTER_NORMAL: 1870 if ((cluster_offset & 511) != 0) { 1871 ret = -EIO; 1872 goto fail; 1873 } 1874 1875 if (bs->encrypted) { 1876 assert(s->crypto); 1877 1878 /* 1879 * For encrypted images, read everything into a temporary 1880 * contiguous buffer on which the AES functions can work. 1881 */ 1882 if (!cluster_data) { 1883 cluster_data = 1884 qemu_try_blockalign(bs->file->bs, 1885 QCOW_MAX_CRYPT_CLUSTERS 1886 * s->cluster_size); 1887 if (cluster_data == NULL) { 1888 ret = -ENOMEM; 1889 goto fail; 1890 } 1891 } 1892 1893 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1894 qemu_iovec_reset(&hd_qiov); 1895 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1896 } 1897 1898 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1899 qemu_co_mutex_unlock(&s->lock); 1900 ret = bdrv_co_preadv(bs->file, 1901 cluster_offset + offset_in_cluster, 1902 cur_bytes, &hd_qiov, 0); 1903 qemu_co_mutex_lock(&s->lock); 1904 if (ret < 0) { 1905 goto fail; 1906 } 1907 if (bs->encrypted) { 1908 assert(s->crypto); 1909 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1910 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1911 if (qcrypto_block_decrypt(s->crypto, 1912 (s->crypt_physical_offset ? 1913 cluster_offset + offset_in_cluster : 1914 offset), 1915 cluster_data, 1916 cur_bytes, 1917 NULL) < 0) { 1918 ret = -EIO; 1919 goto fail; 1920 } 1921 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1922 } 1923 break; 1924 1925 default: 1926 g_assert_not_reached(); 1927 ret = -EIO; 1928 goto fail; 1929 } 1930 1931 bytes -= cur_bytes; 1932 offset += cur_bytes; 1933 bytes_done += cur_bytes; 1934 } 1935 ret = 0; 1936 1937 fail: 1938 qemu_co_mutex_unlock(&s->lock); 1939 1940 qemu_iovec_destroy(&hd_qiov); 1941 qemu_vfree(cluster_data); 1942 1943 return ret; 1944 } 1945 1946 /* Check if it's possible to merge a write request with the writing of 1947 * the data from the COW regions */ 1948 static bool merge_cow(uint64_t offset, unsigned bytes, 1949 QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) 1950 { 1951 QCowL2Meta *m; 1952 1953 for (m = l2meta; m != NULL; m = m->next) { 1954 /* If both COW regions are empty then there's nothing to merge */ 1955 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 1956 continue; 1957 } 1958 1959 /* The data (middle) region must be immediately after the 1960 * start region */ 1961 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 1962 continue; 1963 } 1964 1965 /* The end region must be immediately after the data (middle) 1966 * region */ 1967 if (m->offset + m->cow_end.offset != offset + bytes) { 1968 continue; 1969 } 1970 1971 /* Make sure that adding both COW regions to the QEMUIOVector 1972 * does not exceed IOV_MAX */ 1973 if (hd_qiov->niov > IOV_MAX - 2) { 1974 continue; 1975 } 1976 1977 m->data_qiov = hd_qiov; 1978 return true; 1979 } 1980 1981 return false; 1982 } 1983 1984 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 1985 uint64_t bytes, QEMUIOVector *qiov, 1986 int flags) 1987 { 1988 BDRVQcow2State *s = bs->opaque; 1989 int offset_in_cluster; 1990 int ret; 1991 unsigned int cur_bytes; /* number of sectors in current iteration */ 1992 uint64_t cluster_offset; 1993 QEMUIOVector hd_qiov; 1994 uint64_t bytes_done = 0; 1995 uint8_t *cluster_data = NULL; 1996 QCowL2Meta *l2meta = NULL; 1997 1998 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 1999 2000 qemu_iovec_init(&hd_qiov, qiov->niov); 2001 2002 s->cluster_cache_offset = -1; /* disable compressed cache */ 2003 2004 qemu_co_mutex_lock(&s->lock); 2005 2006 while (bytes != 0) { 2007 2008 l2meta = NULL; 2009 2010 trace_qcow2_writev_start_part(qemu_coroutine_self()); 2011 offset_in_cluster = offset_into_cluster(s, offset); 2012 cur_bytes = MIN(bytes, INT_MAX); 2013 if (bs->encrypted) { 2014 cur_bytes = MIN(cur_bytes, 2015 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 2016 - offset_in_cluster); 2017 } 2018 2019 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2020 &cluster_offset, &l2meta); 2021 if (ret < 0) { 2022 goto fail; 2023 } 2024 2025 assert((cluster_offset & 511) == 0); 2026 2027 qemu_iovec_reset(&hd_qiov); 2028 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 2029 2030 if (bs->encrypted) { 2031 assert(s->crypto); 2032 if (!cluster_data) { 2033 cluster_data = qemu_try_blockalign(bs->file->bs, 2034 QCOW_MAX_CRYPT_CLUSTERS 2035 * s->cluster_size); 2036 if (cluster_data == NULL) { 2037 ret = -ENOMEM; 2038 goto fail; 2039 } 2040 } 2041 2042 assert(hd_qiov.size <= 2043 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2044 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 2045 2046 if (qcrypto_block_encrypt(s->crypto, 2047 (s->crypt_physical_offset ? 2048 cluster_offset + offset_in_cluster : 2049 offset), 2050 cluster_data, 2051 cur_bytes, NULL) < 0) { 2052 ret = -EIO; 2053 goto fail; 2054 } 2055 2056 qemu_iovec_reset(&hd_qiov); 2057 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 2058 } 2059 2060 ret = qcow2_pre_write_overlap_check(bs, 0, 2061 cluster_offset + offset_in_cluster, cur_bytes); 2062 if (ret < 0) { 2063 goto fail; 2064 } 2065 2066 /* If we need to do COW, check if it's possible to merge the 2067 * writing of the guest data together with that of the COW regions. 2068 * If it's not possible (or not necessary) then write the 2069 * guest data now. */ 2070 if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { 2071 qemu_co_mutex_unlock(&s->lock); 2072 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 2073 trace_qcow2_writev_data(qemu_coroutine_self(), 2074 cluster_offset + offset_in_cluster); 2075 ret = bdrv_co_pwritev(bs->file, 2076 cluster_offset + offset_in_cluster, 2077 cur_bytes, &hd_qiov, 0); 2078 qemu_co_mutex_lock(&s->lock); 2079 if (ret < 0) { 2080 goto fail; 2081 } 2082 } 2083 2084 ret = qcow2_handle_l2meta(bs, &l2meta, true); 2085 if (ret) { 2086 goto fail; 2087 } 2088 2089 bytes -= cur_bytes; 2090 offset += cur_bytes; 2091 bytes_done += cur_bytes; 2092 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2093 } 2094 ret = 0; 2095 2096 fail: 2097 qcow2_handle_l2meta(bs, &l2meta, false); 2098 2099 qemu_co_mutex_unlock(&s->lock); 2100 2101 qemu_iovec_destroy(&hd_qiov); 2102 qemu_vfree(cluster_data); 2103 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2104 2105 return ret; 2106 } 2107 2108 static int qcow2_inactivate(BlockDriverState *bs) 2109 { 2110 BDRVQcow2State *s = bs->opaque; 2111 int ret, result = 0; 2112 Error *local_err = NULL; 2113 2114 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2115 if (local_err != NULL) { 2116 result = -EINVAL; 2117 error_report_err(local_err); 2118 error_report("Persistent bitmaps are lost for node '%s'", 2119 bdrv_get_device_or_node_name(bs)); 2120 } 2121 2122 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2123 if (ret) { 2124 result = ret; 2125 error_report("Failed to flush the L2 table cache: %s", 2126 strerror(-ret)); 2127 } 2128 2129 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2130 if (ret) { 2131 result = ret; 2132 error_report("Failed to flush the refcount block cache: %s", 2133 strerror(-ret)); 2134 } 2135 2136 if (result == 0) { 2137 qcow2_mark_clean(bs); 2138 } 2139 2140 return result; 2141 } 2142 2143 static void qcow2_close(BlockDriverState *bs) 2144 { 2145 BDRVQcow2State *s = bs->opaque; 2146 qemu_vfree(s->l1_table); 2147 /* else pre-write overlap checks in cache_destroy may crash */ 2148 s->l1_table = NULL; 2149 2150 if (!(s->flags & BDRV_O_INACTIVE)) { 2151 qcow2_inactivate(bs); 2152 } 2153 2154 cache_clean_timer_del(bs); 2155 qcow2_cache_destroy(s->l2_table_cache); 2156 qcow2_cache_destroy(s->refcount_block_cache); 2157 2158 qcrypto_block_free(s->crypto); 2159 s->crypto = NULL; 2160 2161 g_free(s->unknown_header_fields); 2162 cleanup_unknown_header_ext(bs); 2163 2164 g_free(s->image_backing_file); 2165 g_free(s->image_backing_format); 2166 2167 g_free(s->cluster_cache); 2168 qemu_vfree(s->cluster_data); 2169 qcow2_refcount_close(bs); 2170 qcow2_free_snapshots(bs); 2171 } 2172 2173 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, 2174 Error **errp) 2175 { 2176 BDRVQcow2State *s = bs->opaque; 2177 int flags = s->flags; 2178 QCryptoBlock *crypto = NULL; 2179 QDict *options; 2180 Error *local_err = NULL; 2181 int ret; 2182 2183 /* 2184 * Backing files are read-only which makes all of their metadata immutable, 2185 * that means we don't have to worry about reopening them here. 2186 */ 2187 2188 crypto = s->crypto; 2189 s->crypto = NULL; 2190 2191 qcow2_close(bs); 2192 2193 memset(s, 0, sizeof(BDRVQcow2State)); 2194 options = qdict_clone_shallow(bs->options); 2195 2196 flags &= ~BDRV_O_INACTIVE; 2197 qemu_co_mutex_lock(&s->lock); 2198 ret = qcow2_do_open(bs, options, flags, &local_err); 2199 qemu_co_mutex_unlock(&s->lock); 2200 qobject_unref(options); 2201 if (local_err) { 2202 error_propagate(errp, local_err); 2203 error_prepend(errp, "Could not reopen qcow2 layer: "); 2204 bs->drv = NULL; 2205 return; 2206 } else if (ret < 0) { 2207 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2208 bs->drv = NULL; 2209 return; 2210 } 2211 2212 s->crypto = crypto; 2213 } 2214 2215 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2216 size_t len, size_t buflen) 2217 { 2218 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2219 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2220 2221 if (buflen < ext_len) { 2222 return -ENOSPC; 2223 } 2224 2225 *ext_backing_fmt = (QCowExtension) { 2226 .magic = cpu_to_be32(magic), 2227 .len = cpu_to_be32(len), 2228 }; 2229 2230 if (len) { 2231 memcpy(buf + sizeof(QCowExtension), s, len); 2232 } 2233 2234 return ext_len; 2235 } 2236 2237 /* 2238 * Updates the qcow2 header, including the variable length parts of it, i.e. 2239 * the backing file name and all extensions. qcow2 was not designed to allow 2240 * such changes, so if we run out of space (we can only use the first cluster) 2241 * this function may fail. 2242 * 2243 * Returns 0 on success, -errno in error cases. 2244 */ 2245 int qcow2_update_header(BlockDriverState *bs) 2246 { 2247 BDRVQcow2State *s = bs->opaque; 2248 QCowHeader *header; 2249 char *buf; 2250 size_t buflen = s->cluster_size; 2251 int ret; 2252 uint64_t total_size; 2253 uint32_t refcount_table_clusters; 2254 size_t header_length; 2255 Qcow2UnknownHeaderExtension *uext; 2256 2257 buf = qemu_blockalign(bs, buflen); 2258 2259 /* Header structure */ 2260 header = (QCowHeader*) buf; 2261 2262 if (buflen < sizeof(*header)) { 2263 ret = -ENOSPC; 2264 goto fail; 2265 } 2266 2267 header_length = sizeof(*header) + s->unknown_header_fields_size; 2268 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2269 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2270 2271 *header = (QCowHeader) { 2272 /* Version 2 fields */ 2273 .magic = cpu_to_be32(QCOW_MAGIC), 2274 .version = cpu_to_be32(s->qcow_version), 2275 .backing_file_offset = 0, 2276 .backing_file_size = 0, 2277 .cluster_bits = cpu_to_be32(s->cluster_bits), 2278 .size = cpu_to_be64(total_size), 2279 .crypt_method = cpu_to_be32(s->crypt_method_header), 2280 .l1_size = cpu_to_be32(s->l1_size), 2281 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2282 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2283 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2284 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2285 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2286 2287 /* Version 3 fields */ 2288 .incompatible_features = cpu_to_be64(s->incompatible_features), 2289 .compatible_features = cpu_to_be64(s->compatible_features), 2290 .autoclear_features = cpu_to_be64(s->autoclear_features), 2291 .refcount_order = cpu_to_be32(s->refcount_order), 2292 .header_length = cpu_to_be32(header_length), 2293 }; 2294 2295 /* For older versions, write a shorter header */ 2296 switch (s->qcow_version) { 2297 case 2: 2298 ret = offsetof(QCowHeader, incompatible_features); 2299 break; 2300 case 3: 2301 ret = sizeof(*header); 2302 break; 2303 default: 2304 ret = -EINVAL; 2305 goto fail; 2306 } 2307 2308 buf += ret; 2309 buflen -= ret; 2310 memset(buf, 0, buflen); 2311 2312 /* Preserve any unknown field in the header */ 2313 if (s->unknown_header_fields_size) { 2314 if (buflen < s->unknown_header_fields_size) { 2315 ret = -ENOSPC; 2316 goto fail; 2317 } 2318 2319 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2320 buf += s->unknown_header_fields_size; 2321 buflen -= s->unknown_header_fields_size; 2322 } 2323 2324 /* Backing file format header extension */ 2325 if (s->image_backing_format) { 2326 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2327 s->image_backing_format, 2328 strlen(s->image_backing_format), 2329 buflen); 2330 if (ret < 0) { 2331 goto fail; 2332 } 2333 2334 buf += ret; 2335 buflen -= ret; 2336 } 2337 2338 /* Full disk encryption header pointer extension */ 2339 if (s->crypto_header.offset != 0) { 2340 cpu_to_be64s(&s->crypto_header.offset); 2341 cpu_to_be64s(&s->crypto_header.length); 2342 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2343 &s->crypto_header, sizeof(s->crypto_header), 2344 buflen); 2345 be64_to_cpus(&s->crypto_header.offset); 2346 be64_to_cpus(&s->crypto_header.length); 2347 if (ret < 0) { 2348 goto fail; 2349 } 2350 buf += ret; 2351 buflen -= ret; 2352 } 2353 2354 /* Feature table */ 2355 if (s->qcow_version >= 3) { 2356 Qcow2Feature features[] = { 2357 { 2358 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2359 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2360 .name = "dirty bit", 2361 }, 2362 { 2363 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2364 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2365 .name = "corrupt bit", 2366 }, 2367 { 2368 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2369 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2370 .name = "lazy refcounts", 2371 }, 2372 }; 2373 2374 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2375 features, sizeof(features), buflen); 2376 if (ret < 0) { 2377 goto fail; 2378 } 2379 buf += ret; 2380 buflen -= ret; 2381 } 2382 2383 /* Bitmap extension */ 2384 if (s->nb_bitmaps > 0) { 2385 Qcow2BitmapHeaderExt bitmaps_header = { 2386 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2387 .bitmap_directory_size = 2388 cpu_to_be64(s->bitmap_directory_size), 2389 .bitmap_directory_offset = 2390 cpu_to_be64(s->bitmap_directory_offset) 2391 }; 2392 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2393 &bitmaps_header, sizeof(bitmaps_header), 2394 buflen); 2395 if (ret < 0) { 2396 goto fail; 2397 } 2398 buf += ret; 2399 buflen -= ret; 2400 } 2401 2402 /* Keep unknown header extensions */ 2403 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2404 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2405 if (ret < 0) { 2406 goto fail; 2407 } 2408 2409 buf += ret; 2410 buflen -= ret; 2411 } 2412 2413 /* End of header extensions */ 2414 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2415 if (ret < 0) { 2416 goto fail; 2417 } 2418 2419 buf += ret; 2420 buflen -= ret; 2421 2422 /* Backing file name */ 2423 if (s->image_backing_file) { 2424 size_t backing_file_len = strlen(s->image_backing_file); 2425 2426 if (buflen < backing_file_len) { 2427 ret = -ENOSPC; 2428 goto fail; 2429 } 2430 2431 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2432 strncpy(buf, s->image_backing_file, buflen); 2433 2434 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2435 header->backing_file_size = cpu_to_be32(backing_file_len); 2436 } 2437 2438 /* Write the new header */ 2439 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2440 if (ret < 0) { 2441 goto fail; 2442 } 2443 2444 ret = 0; 2445 fail: 2446 qemu_vfree(header); 2447 return ret; 2448 } 2449 2450 static int qcow2_change_backing_file(BlockDriverState *bs, 2451 const char *backing_file, const char *backing_fmt) 2452 { 2453 BDRVQcow2State *s = bs->opaque; 2454 2455 if (backing_file && strlen(backing_file) > 1023) { 2456 return -EINVAL; 2457 } 2458 2459 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2460 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2461 2462 g_free(s->image_backing_file); 2463 g_free(s->image_backing_format); 2464 2465 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2466 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2467 2468 return qcow2_update_header(bs); 2469 } 2470 2471 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2472 { 2473 if (g_str_equal(encryptfmt, "luks")) { 2474 return QCOW_CRYPT_LUKS; 2475 } else if (g_str_equal(encryptfmt, "aes")) { 2476 return QCOW_CRYPT_AES; 2477 } else { 2478 return -EINVAL; 2479 } 2480 } 2481 2482 static int qcow2_set_up_encryption(BlockDriverState *bs, 2483 QCryptoBlockCreateOptions *cryptoopts, 2484 Error **errp) 2485 { 2486 BDRVQcow2State *s = bs->opaque; 2487 QCryptoBlock *crypto = NULL; 2488 int fmt, ret; 2489 2490 switch (cryptoopts->format) { 2491 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 2492 fmt = QCOW_CRYPT_LUKS; 2493 break; 2494 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 2495 fmt = QCOW_CRYPT_AES; 2496 break; 2497 default: 2498 error_setg(errp, "Crypto format not supported in qcow2"); 2499 return -EINVAL; 2500 } 2501 2502 s->crypt_method_header = fmt; 2503 2504 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2505 qcow2_crypto_hdr_init_func, 2506 qcow2_crypto_hdr_write_func, 2507 bs, errp); 2508 if (!crypto) { 2509 return -EINVAL; 2510 } 2511 2512 ret = qcow2_update_header(bs); 2513 if (ret < 0) { 2514 error_setg_errno(errp, -ret, "Could not write encryption header"); 2515 goto out; 2516 } 2517 2518 ret = 0; 2519 out: 2520 qcrypto_block_free(crypto); 2521 return ret; 2522 } 2523 2524 2525 typedef struct PreallocCo { 2526 BlockDriverState *bs; 2527 uint64_t offset; 2528 uint64_t new_length; 2529 2530 int ret; 2531 } PreallocCo; 2532 2533 /** 2534 * Preallocates metadata structures for data clusters between @offset (in the 2535 * guest disk) and @new_length (which is thus generally the new guest disk 2536 * size). 2537 * 2538 * Returns: 0 on success, -errno on failure. 2539 */ 2540 static void coroutine_fn preallocate_co(void *opaque) 2541 { 2542 PreallocCo *params = opaque; 2543 BlockDriverState *bs = params->bs; 2544 uint64_t offset = params->offset; 2545 uint64_t new_length = params->new_length; 2546 BDRVQcow2State *s = bs->opaque; 2547 uint64_t bytes; 2548 uint64_t host_offset = 0; 2549 unsigned int cur_bytes; 2550 int ret; 2551 QCowL2Meta *meta; 2552 2553 qemu_co_mutex_lock(&s->lock); 2554 2555 assert(offset <= new_length); 2556 bytes = new_length - offset; 2557 2558 while (bytes) { 2559 cur_bytes = MIN(bytes, INT_MAX); 2560 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2561 &host_offset, &meta); 2562 if (ret < 0) { 2563 goto done; 2564 } 2565 2566 while (meta) { 2567 QCowL2Meta *next = meta->next; 2568 2569 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2570 if (ret < 0) { 2571 qcow2_free_any_clusters(bs, meta->alloc_offset, 2572 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2573 goto done; 2574 } 2575 2576 /* There are no dependent requests, but we need to remove our 2577 * request from the list of in-flight requests */ 2578 QLIST_REMOVE(meta, next_in_flight); 2579 2580 g_free(meta); 2581 meta = next; 2582 } 2583 2584 /* TODO Preallocate data if requested */ 2585 2586 bytes -= cur_bytes; 2587 offset += cur_bytes; 2588 } 2589 2590 /* 2591 * It is expected that the image file is large enough to actually contain 2592 * all of the allocated clusters (otherwise we get failing reads after 2593 * EOF). Extend the image to the last allocated sector. 2594 */ 2595 if (host_offset != 0) { 2596 uint8_t data = 0; 2597 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2598 &data, 1); 2599 if (ret < 0) { 2600 goto done; 2601 } 2602 } 2603 2604 ret = 0; 2605 2606 done: 2607 qemu_co_mutex_unlock(&s->lock); 2608 params->ret = ret; 2609 } 2610 2611 static int preallocate(BlockDriverState *bs, 2612 uint64_t offset, uint64_t new_length) 2613 { 2614 PreallocCo params = { 2615 .bs = bs, 2616 .offset = offset, 2617 .new_length = new_length, 2618 .ret = -EINPROGRESS, 2619 }; 2620 2621 if (qemu_in_coroutine()) { 2622 preallocate_co(¶ms); 2623 } else { 2624 Coroutine *co = qemu_coroutine_create(preallocate_co, ¶ms); 2625 bdrv_coroutine_enter(bs, co); 2626 BDRV_POLL_WHILE(bs, params.ret == -EINPROGRESS); 2627 } 2628 return params.ret; 2629 } 2630 2631 /* qcow2_refcount_metadata_size: 2632 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2633 * @cluster_size: size of a cluster, in bytes 2634 * @refcount_order: refcount bits power-of-2 exponent 2635 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2636 * needs to be 2637 * 2638 * Returns: Number of bytes required for refcount blocks and table metadata. 2639 */ 2640 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2641 int refcount_order, bool generous_increase, 2642 uint64_t *refblock_count) 2643 { 2644 /* 2645 * Every host cluster is reference-counted, including metadata (even 2646 * refcount metadata is recursively included). 2647 * 2648 * An accurate formula for the size of refcount metadata size is difficult 2649 * to derive. An easier method of calculation is finding the fixed point 2650 * where no further refcount blocks or table clusters are required to 2651 * reference count every cluster. 2652 */ 2653 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2654 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2655 int64_t table = 0; /* number of refcount table clusters */ 2656 int64_t blocks = 0; /* number of refcount block clusters */ 2657 int64_t last; 2658 int64_t n = 0; 2659 2660 do { 2661 last = n; 2662 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2663 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2664 n = clusters + blocks + table; 2665 2666 if (n == last && generous_increase) { 2667 clusters += DIV_ROUND_UP(table, 2); 2668 n = 0; /* force another loop */ 2669 generous_increase = false; 2670 } 2671 } while (n != last); 2672 2673 if (refblock_count) { 2674 *refblock_count = blocks; 2675 } 2676 2677 return (blocks + table) * cluster_size; 2678 } 2679 2680 /** 2681 * qcow2_calc_prealloc_size: 2682 * @total_size: virtual disk size in bytes 2683 * @cluster_size: cluster size in bytes 2684 * @refcount_order: refcount bits power-of-2 exponent 2685 * 2686 * Returns: Total number of bytes required for the fully allocated image 2687 * (including metadata). 2688 */ 2689 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2690 size_t cluster_size, 2691 int refcount_order) 2692 { 2693 int64_t meta_size = 0; 2694 uint64_t nl1e, nl2e; 2695 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); 2696 2697 /* header: 1 cluster */ 2698 meta_size += cluster_size; 2699 2700 /* total size of L2 tables */ 2701 nl2e = aligned_total_size / cluster_size; 2702 nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t)); 2703 meta_size += nl2e * sizeof(uint64_t); 2704 2705 /* total size of L1 tables */ 2706 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2707 nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t)); 2708 meta_size += nl1e * sizeof(uint64_t); 2709 2710 /* total size of refcount table and blocks */ 2711 meta_size += qcow2_refcount_metadata_size( 2712 (meta_size + aligned_total_size) / cluster_size, 2713 cluster_size, refcount_order, false, NULL); 2714 2715 return meta_size + aligned_total_size; 2716 } 2717 2718 static bool validate_cluster_size(size_t cluster_size, Error **errp) 2719 { 2720 int cluster_bits = ctz32(cluster_size); 2721 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2722 (1 << cluster_bits) != cluster_size) 2723 { 2724 error_setg(errp, "Cluster size must be a power of two between %d and " 2725 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2726 return false; 2727 } 2728 return true; 2729 } 2730 2731 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2732 { 2733 size_t cluster_size; 2734 2735 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2736 DEFAULT_CLUSTER_SIZE); 2737 if (!validate_cluster_size(cluster_size, errp)) { 2738 return 0; 2739 } 2740 return cluster_size; 2741 } 2742 2743 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2744 { 2745 char *buf; 2746 int ret; 2747 2748 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2749 if (!buf) { 2750 ret = 3; /* default */ 2751 } else if (!strcmp(buf, "0.10")) { 2752 ret = 2; 2753 } else if (!strcmp(buf, "1.1")) { 2754 ret = 3; 2755 } else { 2756 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2757 ret = -EINVAL; 2758 } 2759 g_free(buf); 2760 return ret; 2761 } 2762 2763 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 2764 Error **errp) 2765 { 2766 uint64_t refcount_bits; 2767 2768 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 2769 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2770 error_setg(errp, "Refcount width must be a power of two and may not " 2771 "exceed 64 bits"); 2772 return 0; 2773 } 2774 2775 if (version < 3 && refcount_bits != 16) { 2776 error_setg(errp, "Different refcount widths than 16 bits require " 2777 "compatibility level 1.1 or above (use compat=1.1 or " 2778 "greater)"); 2779 return 0; 2780 } 2781 2782 return refcount_bits; 2783 } 2784 2785 static int coroutine_fn 2786 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 2787 { 2788 BlockdevCreateOptionsQcow2 *qcow2_opts; 2789 QDict *options; 2790 2791 /* 2792 * Open the image file and write a minimal qcow2 header. 2793 * 2794 * We keep things simple and start with a zero-sized image. We also 2795 * do without refcount blocks or a L1 table for now. We'll fix the 2796 * inconsistency later. 2797 * 2798 * We do need a refcount table because growing the refcount table means 2799 * allocating two new refcount blocks - the seconds of which would be at 2800 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2801 * size for any qcow2 image. 2802 */ 2803 BlockBackend *blk = NULL; 2804 BlockDriverState *bs = NULL; 2805 QCowHeader *header; 2806 size_t cluster_size; 2807 int version; 2808 int refcount_order; 2809 uint64_t* refcount_table; 2810 Error *local_err = NULL; 2811 int ret; 2812 2813 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); 2814 qcow2_opts = &create_options->u.qcow2; 2815 2816 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); 2817 if (bs == NULL) { 2818 return -EIO; 2819 } 2820 2821 /* Validate options and set default values */ 2822 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { 2823 error_setg(errp, "Image size must be a multiple of 512 bytes"); 2824 ret = -EINVAL; 2825 goto out; 2826 } 2827 2828 if (qcow2_opts->has_version) { 2829 switch (qcow2_opts->version) { 2830 case BLOCKDEV_QCOW2_VERSION_V2: 2831 version = 2; 2832 break; 2833 case BLOCKDEV_QCOW2_VERSION_V3: 2834 version = 3; 2835 break; 2836 default: 2837 g_assert_not_reached(); 2838 } 2839 } else { 2840 version = 3; 2841 } 2842 2843 if (qcow2_opts->has_cluster_size) { 2844 cluster_size = qcow2_opts->cluster_size; 2845 } else { 2846 cluster_size = DEFAULT_CLUSTER_SIZE; 2847 } 2848 2849 if (!validate_cluster_size(cluster_size, errp)) { 2850 ret = -EINVAL; 2851 goto out; 2852 } 2853 2854 if (!qcow2_opts->has_preallocation) { 2855 qcow2_opts->preallocation = PREALLOC_MODE_OFF; 2856 } 2857 if (qcow2_opts->has_backing_file && 2858 qcow2_opts->preallocation != PREALLOC_MODE_OFF) 2859 { 2860 error_setg(errp, "Backing file and preallocation cannot be used at " 2861 "the same time"); 2862 ret = -EINVAL; 2863 goto out; 2864 } 2865 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { 2866 error_setg(errp, "Backing format cannot be used without backing file"); 2867 ret = -EINVAL; 2868 goto out; 2869 } 2870 2871 if (!qcow2_opts->has_lazy_refcounts) { 2872 qcow2_opts->lazy_refcounts = false; 2873 } 2874 if (version < 3 && qcow2_opts->lazy_refcounts) { 2875 error_setg(errp, "Lazy refcounts only supported with compatibility " 2876 "level 1.1 and above (use version=v3 or greater)"); 2877 ret = -EINVAL; 2878 goto out; 2879 } 2880 2881 if (!qcow2_opts->has_refcount_bits) { 2882 qcow2_opts->refcount_bits = 16; 2883 } 2884 if (qcow2_opts->refcount_bits > 64 || 2885 !is_power_of_2(qcow2_opts->refcount_bits)) 2886 { 2887 error_setg(errp, "Refcount width must be a power of two and may not " 2888 "exceed 64 bits"); 2889 ret = -EINVAL; 2890 goto out; 2891 } 2892 if (version < 3 && qcow2_opts->refcount_bits != 16) { 2893 error_setg(errp, "Different refcount widths than 16 bits require " 2894 "compatibility level 1.1 or above (use version=v3 or " 2895 "greater)"); 2896 ret = -EINVAL; 2897 goto out; 2898 } 2899 refcount_order = ctz32(qcow2_opts->refcount_bits); 2900 2901 2902 /* Create BlockBackend to write to the image */ 2903 blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 2904 ret = blk_insert_bs(blk, bs, errp); 2905 if (ret < 0) { 2906 goto out; 2907 } 2908 blk_set_allow_write_beyond_eof(blk, true); 2909 2910 /* Clear the protocol layer and preallocate it if necessary */ 2911 ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); 2912 if (ret < 0) { 2913 goto out; 2914 } 2915 2916 if (qcow2_opts->preallocation == PREALLOC_MODE_FULL || 2917 qcow2_opts->preallocation == PREALLOC_MODE_FALLOC) 2918 { 2919 int64_t prealloc_size = 2920 qcow2_calc_prealloc_size(qcow2_opts->size, cluster_size, 2921 refcount_order); 2922 2923 ret = blk_truncate(blk, prealloc_size, qcow2_opts->preallocation, errp); 2924 if (ret < 0) { 2925 goto out; 2926 } 2927 } 2928 2929 /* Write the header */ 2930 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2931 header = g_malloc0(cluster_size); 2932 *header = (QCowHeader) { 2933 .magic = cpu_to_be32(QCOW_MAGIC), 2934 .version = cpu_to_be32(version), 2935 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 2936 .size = cpu_to_be64(0), 2937 .l1_table_offset = cpu_to_be64(0), 2938 .l1_size = cpu_to_be32(0), 2939 .refcount_table_offset = cpu_to_be64(cluster_size), 2940 .refcount_table_clusters = cpu_to_be32(1), 2941 .refcount_order = cpu_to_be32(refcount_order), 2942 .header_length = cpu_to_be32(sizeof(*header)), 2943 }; 2944 2945 /* We'll update this to correct value later */ 2946 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2947 2948 if (qcow2_opts->lazy_refcounts) { 2949 header->compatible_features |= 2950 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2951 } 2952 2953 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2954 g_free(header); 2955 if (ret < 0) { 2956 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2957 goto out; 2958 } 2959 2960 /* Write a refcount table with one refcount block */ 2961 refcount_table = g_malloc0(2 * cluster_size); 2962 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2963 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2964 g_free(refcount_table); 2965 2966 if (ret < 0) { 2967 error_setg_errno(errp, -ret, "Could not write refcount table"); 2968 goto out; 2969 } 2970 2971 blk_unref(blk); 2972 blk = NULL; 2973 2974 /* 2975 * And now open the image and make it consistent first (i.e. increase the 2976 * refcount of the cluster that is occupied by the header and the refcount 2977 * table) 2978 */ 2979 options = qdict_new(); 2980 qdict_put_str(options, "driver", "qcow2"); 2981 qdict_put_str(options, "file", bs->node_name); 2982 blk = blk_new_open(NULL, NULL, options, 2983 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 2984 &local_err); 2985 if (blk == NULL) { 2986 error_propagate(errp, local_err); 2987 ret = -EIO; 2988 goto out; 2989 } 2990 2991 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2992 if (ret < 0) { 2993 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2994 "header and refcount table"); 2995 goto out; 2996 2997 } else if (ret != 0) { 2998 error_report("Huh, first cluster in empty image is already in use?"); 2999 abort(); 3000 } 3001 3002 /* Create a full header (including things like feature table) */ 3003 ret = qcow2_update_header(blk_bs(blk)); 3004 if (ret < 0) { 3005 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 3006 goto out; 3007 } 3008 3009 /* Okay, now that we have a valid image, let's give it the right size */ 3010 ret = blk_truncate(blk, qcow2_opts->size, PREALLOC_MODE_OFF, errp); 3011 if (ret < 0) { 3012 error_prepend(errp, "Could not resize image: "); 3013 goto out; 3014 } 3015 3016 /* Want a backing file? There you go.*/ 3017 if (qcow2_opts->has_backing_file) { 3018 const char *backing_format = NULL; 3019 3020 if (qcow2_opts->has_backing_fmt) { 3021 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); 3022 } 3023 3024 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, 3025 backing_format); 3026 if (ret < 0) { 3027 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 3028 "with format '%s'", qcow2_opts->backing_file, 3029 backing_format); 3030 goto out; 3031 } 3032 } 3033 3034 /* Want encryption? There you go. */ 3035 if (qcow2_opts->has_encrypt) { 3036 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); 3037 if (ret < 0) { 3038 goto out; 3039 } 3040 } 3041 3042 /* And if we're supposed to preallocate metadata, do that now */ 3043 if (qcow2_opts->preallocation != PREALLOC_MODE_OFF) { 3044 ret = preallocate(blk_bs(blk), 0, qcow2_opts->size); 3045 if (ret < 0) { 3046 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 3047 goto out; 3048 } 3049 } 3050 3051 blk_unref(blk); 3052 blk = NULL; 3053 3054 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 3055 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 3056 * have to setup decryption context. We're not doing any I/O on the top 3057 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 3058 * not have effect. 3059 */ 3060 options = qdict_new(); 3061 qdict_put_str(options, "driver", "qcow2"); 3062 qdict_put_str(options, "file", bs->node_name); 3063 blk = blk_new_open(NULL, NULL, options, 3064 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 3065 &local_err); 3066 if (blk == NULL) { 3067 error_propagate(errp, local_err); 3068 ret = -EIO; 3069 goto out; 3070 } 3071 3072 ret = 0; 3073 out: 3074 blk_unref(blk); 3075 bdrv_unref(bs); 3076 return ret; 3077 } 3078 3079 static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts, 3080 Error **errp) 3081 { 3082 BlockdevCreateOptions *create_options = NULL; 3083 QDict *qdict; 3084 Visitor *v; 3085 BlockDriverState *bs = NULL; 3086 Error *local_err = NULL; 3087 const char *val; 3088 int ret; 3089 3090 /* Only the keyval visitor supports the dotted syntax needed for 3091 * encryption, so go through a QDict before getting a QAPI type. Ignore 3092 * options meant for the protocol layer so that the visitor doesn't 3093 * complain. */ 3094 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, 3095 true); 3096 3097 /* Handle encryption options */ 3098 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 3099 if (val && !strcmp(val, "on")) { 3100 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 3101 } else if (val && !strcmp(val, "off")) { 3102 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 3103 } 3104 3105 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 3106 if (val && !strcmp(val, "aes")) { 3107 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 3108 } 3109 3110 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into 3111 * version=v2/v3 below. */ 3112 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); 3113 if (val && !strcmp(val, "0.10")) { 3114 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); 3115 } else if (val && !strcmp(val, "1.1")) { 3116 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); 3117 } 3118 3119 /* Change legacy command line options into QMP ones */ 3120 static const QDictRenames opt_renames[] = { 3121 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 3122 { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, 3123 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, 3124 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, 3125 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, 3126 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 3127 { BLOCK_OPT_COMPAT_LEVEL, "version" }, 3128 { NULL, NULL }, 3129 }; 3130 3131 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 3132 ret = -EINVAL; 3133 goto finish; 3134 } 3135 3136 /* Create and open the file (protocol layer) */ 3137 ret = bdrv_create_file(filename, opts, errp); 3138 if (ret < 0) { 3139 goto finish; 3140 } 3141 3142 bs = bdrv_open(filename, NULL, NULL, 3143 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 3144 if (bs == NULL) { 3145 ret = -EIO; 3146 goto finish; 3147 } 3148 3149 /* Set 'driver' and 'node' options */ 3150 qdict_put_str(qdict, "driver", "qcow2"); 3151 qdict_put_str(qdict, "file", bs->node_name); 3152 3153 /* Now get the QAPI type BlockdevCreateOptions */ 3154 v = qobject_input_visitor_new_flat_confused(qdict, errp); 3155 if (!v) { 3156 ret = -EINVAL; 3157 goto finish; 3158 } 3159 3160 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 3161 visit_free(v); 3162 3163 if (local_err) { 3164 error_propagate(errp, local_err); 3165 ret = -EINVAL; 3166 goto finish; 3167 } 3168 3169 /* Silently round up size */ 3170 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, 3171 BDRV_SECTOR_SIZE); 3172 3173 /* Create the qcow2 image (format layer) */ 3174 ret = qcow2_co_create(create_options, errp); 3175 if (ret < 0) { 3176 goto finish; 3177 } 3178 3179 ret = 0; 3180 finish: 3181 qobject_unref(qdict); 3182 bdrv_unref(bs); 3183 qapi_free_BlockdevCreateOptions(create_options); 3184 return ret; 3185 } 3186 3187 3188 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3189 { 3190 int64_t nr; 3191 int res; 3192 3193 /* Clamp to image length, before checking status of underlying sectors */ 3194 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3195 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3196 } 3197 3198 if (!bytes) { 3199 return true; 3200 } 3201 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3202 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3203 } 3204 3205 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3206 int64_t offset, int bytes, BdrvRequestFlags flags) 3207 { 3208 int ret; 3209 BDRVQcow2State *s = bs->opaque; 3210 3211 uint32_t head = offset % s->cluster_size; 3212 uint32_t tail = (offset + bytes) % s->cluster_size; 3213 3214 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3215 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3216 tail = 0; 3217 } 3218 3219 if (head || tail) { 3220 uint64_t off; 3221 unsigned int nr; 3222 3223 assert(head + bytes <= s->cluster_size); 3224 3225 /* check whether remainder of cluster already reads as zero */ 3226 if (!(is_zero(bs, offset - head, head) && 3227 is_zero(bs, offset + bytes, 3228 tail ? s->cluster_size - tail : 0))) { 3229 return -ENOTSUP; 3230 } 3231 3232 qemu_co_mutex_lock(&s->lock); 3233 /* We can have new write after previous check */ 3234 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3235 bytes = s->cluster_size; 3236 nr = s->cluster_size; 3237 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3238 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3239 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3240 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3241 qemu_co_mutex_unlock(&s->lock); 3242 return -ENOTSUP; 3243 } 3244 } else { 3245 qemu_co_mutex_lock(&s->lock); 3246 } 3247 3248 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3249 3250 /* Whatever is left can use real zero clusters */ 3251 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3252 qemu_co_mutex_unlock(&s->lock); 3253 3254 return ret; 3255 } 3256 3257 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3258 int64_t offset, int bytes) 3259 { 3260 int ret; 3261 BDRVQcow2State *s = bs->opaque; 3262 3263 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3264 assert(bytes < s->cluster_size); 3265 /* Ignore partial clusters, except for the special case of the 3266 * complete partial cluster at the end of an unaligned file */ 3267 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3268 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3269 return -ENOTSUP; 3270 } 3271 } 3272 3273 qemu_co_mutex_lock(&s->lock); 3274 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3275 false); 3276 qemu_co_mutex_unlock(&s->lock); 3277 return ret; 3278 } 3279 3280 static int coroutine_fn 3281 qcow2_co_copy_range_from(BlockDriverState *bs, 3282 BdrvChild *src, uint64_t src_offset, 3283 BdrvChild *dst, uint64_t dst_offset, 3284 uint64_t bytes, BdrvRequestFlags flags) 3285 { 3286 BDRVQcow2State *s = bs->opaque; 3287 int ret; 3288 unsigned int cur_bytes; /* number of bytes in current iteration */ 3289 BdrvChild *child = NULL; 3290 BdrvRequestFlags cur_flags; 3291 3292 assert(!bs->encrypted); 3293 qemu_co_mutex_lock(&s->lock); 3294 3295 while (bytes != 0) { 3296 uint64_t copy_offset = 0; 3297 /* prepare next request */ 3298 cur_bytes = MIN(bytes, INT_MAX); 3299 cur_flags = flags; 3300 3301 ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, ©_offset); 3302 if (ret < 0) { 3303 goto out; 3304 } 3305 3306 switch (ret) { 3307 case QCOW2_CLUSTER_UNALLOCATED: 3308 if (bs->backing && bs->backing->bs) { 3309 int64_t backing_length = bdrv_getlength(bs->backing->bs); 3310 if (src_offset >= backing_length) { 3311 cur_flags |= BDRV_REQ_ZERO_WRITE; 3312 } else { 3313 child = bs->backing; 3314 cur_bytes = MIN(cur_bytes, backing_length - src_offset); 3315 copy_offset = src_offset; 3316 } 3317 } else { 3318 cur_flags |= BDRV_REQ_ZERO_WRITE; 3319 } 3320 break; 3321 3322 case QCOW2_CLUSTER_ZERO_PLAIN: 3323 case QCOW2_CLUSTER_ZERO_ALLOC: 3324 cur_flags |= BDRV_REQ_ZERO_WRITE; 3325 break; 3326 3327 case QCOW2_CLUSTER_COMPRESSED: 3328 ret = -ENOTSUP; 3329 goto out; 3330 break; 3331 3332 case QCOW2_CLUSTER_NORMAL: 3333 child = bs->file; 3334 copy_offset += offset_into_cluster(s, src_offset); 3335 if ((copy_offset & 511) != 0) { 3336 ret = -EIO; 3337 goto out; 3338 } 3339 break; 3340 3341 default: 3342 abort(); 3343 } 3344 qemu_co_mutex_unlock(&s->lock); 3345 ret = bdrv_co_copy_range_from(child, 3346 copy_offset, 3347 dst, dst_offset, 3348 cur_bytes, cur_flags); 3349 qemu_co_mutex_lock(&s->lock); 3350 if (ret < 0) { 3351 goto out; 3352 } 3353 3354 bytes -= cur_bytes; 3355 src_offset += cur_bytes; 3356 dst_offset += cur_bytes; 3357 } 3358 ret = 0; 3359 3360 out: 3361 qemu_co_mutex_unlock(&s->lock); 3362 return ret; 3363 } 3364 3365 static int coroutine_fn 3366 qcow2_co_copy_range_to(BlockDriverState *bs, 3367 BdrvChild *src, uint64_t src_offset, 3368 BdrvChild *dst, uint64_t dst_offset, 3369 uint64_t bytes, BdrvRequestFlags flags) 3370 { 3371 BDRVQcow2State *s = bs->opaque; 3372 int offset_in_cluster; 3373 int ret; 3374 unsigned int cur_bytes; /* number of sectors in current iteration */ 3375 uint64_t cluster_offset; 3376 uint8_t *cluster_data = NULL; 3377 QCowL2Meta *l2meta = NULL; 3378 3379 assert(!bs->encrypted); 3380 s->cluster_cache_offset = -1; /* disable compressed cache */ 3381 3382 qemu_co_mutex_lock(&s->lock); 3383 3384 while (bytes != 0) { 3385 3386 l2meta = NULL; 3387 3388 offset_in_cluster = offset_into_cluster(s, dst_offset); 3389 cur_bytes = MIN(bytes, INT_MAX); 3390 3391 /* TODO: 3392 * If src->bs == dst->bs, we could simply copy by incrementing 3393 * the refcnt, without copying user data. 3394 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ 3395 ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes, 3396 &cluster_offset, &l2meta); 3397 if (ret < 0) { 3398 goto fail; 3399 } 3400 3401 assert((cluster_offset & 511) == 0); 3402 3403 ret = qcow2_pre_write_overlap_check(bs, 0, 3404 cluster_offset + offset_in_cluster, cur_bytes); 3405 if (ret < 0) { 3406 goto fail; 3407 } 3408 3409 qemu_co_mutex_unlock(&s->lock); 3410 ret = bdrv_co_copy_range_to(src, src_offset, 3411 bs->file, 3412 cluster_offset + offset_in_cluster, 3413 cur_bytes, flags); 3414 qemu_co_mutex_lock(&s->lock); 3415 if (ret < 0) { 3416 goto fail; 3417 } 3418 3419 ret = qcow2_handle_l2meta(bs, &l2meta, true); 3420 if (ret) { 3421 goto fail; 3422 } 3423 3424 bytes -= cur_bytes; 3425 dst_offset += cur_bytes; 3426 } 3427 ret = 0; 3428 3429 fail: 3430 qcow2_handle_l2meta(bs, &l2meta, false); 3431 3432 qemu_co_mutex_unlock(&s->lock); 3433 3434 qemu_vfree(cluster_data); 3435 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 3436 3437 return ret; 3438 } 3439 3440 static int qcow2_truncate(BlockDriverState *bs, int64_t offset, 3441 PreallocMode prealloc, Error **errp) 3442 { 3443 BDRVQcow2State *s = bs->opaque; 3444 uint64_t old_length; 3445 int64_t new_l1_size; 3446 int ret; 3447 3448 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3449 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3450 { 3451 error_setg(errp, "Unsupported preallocation mode '%s'", 3452 PreallocMode_str(prealloc)); 3453 return -ENOTSUP; 3454 } 3455 3456 if (offset & 511) { 3457 error_setg(errp, "The new size must be a multiple of 512"); 3458 return -EINVAL; 3459 } 3460 3461 /* cannot proceed if image has snapshots */ 3462 if (s->nb_snapshots) { 3463 error_setg(errp, "Can't resize an image which has snapshots"); 3464 return -ENOTSUP; 3465 } 3466 3467 /* cannot proceed if image has bitmaps */ 3468 if (s->nb_bitmaps) { 3469 /* TODO: resize bitmaps in the image */ 3470 error_setg(errp, "Can't resize an image which has bitmaps"); 3471 return -ENOTSUP; 3472 } 3473 3474 old_length = bs->total_sectors * 512; 3475 new_l1_size = size_to_l1(s, offset); 3476 3477 if (offset < old_length) { 3478 int64_t last_cluster, old_file_size; 3479 if (prealloc != PREALLOC_MODE_OFF) { 3480 error_setg(errp, 3481 "Preallocation can't be used for shrinking an image"); 3482 return -EINVAL; 3483 } 3484 3485 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3486 old_length - ROUND_UP(offset, 3487 s->cluster_size), 3488 QCOW2_DISCARD_ALWAYS, true); 3489 if (ret < 0) { 3490 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3491 return ret; 3492 } 3493 3494 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3495 if (ret < 0) { 3496 error_setg_errno(errp, -ret, 3497 "Failed to reduce the number of L2 tables"); 3498 return ret; 3499 } 3500 3501 ret = qcow2_shrink_reftable(bs); 3502 if (ret < 0) { 3503 error_setg_errno(errp, -ret, 3504 "Failed to discard unused refblocks"); 3505 return ret; 3506 } 3507 3508 old_file_size = bdrv_getlength(bs->file->bs); 3509 if (old_file_size < 0) { 3510 error_setg_errno(errp, -old_file_size, 3511 "Failed to inquire current file length"); 3512 return old_file_size; 3513 } 3514 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3515 if (last_cluster < 0) { 3516 error_setg_errno(errp, -last_cluster, 3517 "Failed to find the last cluster"); 3518 return last_cluster; 3519 } 3520 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3521 Error *local_err = NULL; 3522 3523 bdrv_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3524 PREALLOC_MODE_OFF, &local_err); 3525 if (local_err) { 3526 warn_reportf_err(local_err, 3527 "Failed to truncate the tail of the image: "); 3528 } 3529 } 3530 } else { 3531 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3532 if (ret < 0) { 3533 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3534 return ret; 3535 } 3536 } 3537 3538 switch (prealloc) { 3539 case PREALLOC_MODE_OFF: 3540 break; 3541 3542 case PREALLOC_MODE_METADATA: 3543 ret = preallocate(bs, old_length, offset); 3544 if (ret < 0) { 3545 error_setg_errno(errp, -ret, "Preallocation failed"); 3546 return ret; 3547 } 3548 break; 3549 3550 case PREALLOC_MODE_FALLOC: 3551 case PREALLOC_MODE_FULL: 3552 { 3553 int64_t allocation_start, host_offset, guest_offset; 3554 int64_t clusters_allocated; 3555 int64_t old_file_size, new_file_size; 3556 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3557 3558 old_file_size = bdrv_getlength(bs->file->bs); 3559 if (old_file_size < 0) { 3560 error_setg_errno(errp, -old_file_size, 3561 "Failed to inquire current file length"); 3562 return old_file_size; 3563 } 3564 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3565 3566 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3567 s->cluster_size); 3568 3569 /* This is an overestimation; we will not actually allocate space for 3570 * these in the file but just make sure the new refcount structures are 3571 * able to cover them so we will not have to allocate new refblocks 3572 * while entering the data blocks in the potentially new L2 tables. 3573 * (We do not actually care where the L2 tables are placed. Maybe they 3574 * are already allocated or they can be placed somewhere before 3575 * @old_file_size. It does not matter because they will be fully 3576 * allocated automatically, so they do not need to be covered by the 3577 * preallocation. All that matters is that we will not have to allocate 3578 * new refcount structures for them.) */ 3579 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3580 s->cluster_size / sizeof(uint64_t)); 3581 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3582 * table for a potential head/tail */ 3583 nb_new_l2_tables++; 3584 3585 allocation_start = qcow2_refcount_area(bs, old_file_size, 3586 nb_new_data_clusters + 3587 nb_new_l2_tables, 3588 true, 0, 0); 3589 if (allocation_start < 0) { 3590 error_setg_errno(errp, -allocation_start, 3591 "Failed to resize refcount structures"); 3592 return allocation_start; 3593 } 3594 3595 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3596 nb_new_data_clusters); 3597 if (clusters_allocated < 0) { 3598 error_setg_errno(errp, -clusters_allocated, 3599 "Failed to allocate data clusters"); 3600 return -clusters_allocated; 3601 } 3602 3603 assert(clusters_allocated == nb_new_data_clusters); 3604 3605 /* Allocate the data area */ 3606 new_file_size = allocation_start + 3607 nb_new_data_clusters * s->cluster_size; 3608 ret = bdrv_truncate(bs->file, new_file_size, prealloc, errp); 3609 if (ret < 0) { 3610 error_prepend(errp, "Failed to resize underlying file: "); 3611 qcow2_free_clusters(bs, allocation_start, 3612 nb_new_data_clusters * s->cluster_size, 3613 QCOW2_DISCARD_OTHER); 3614 return ret; 3615 } 3616 3617 /* Create the necessary L2 entries */ 3618 host_offset = allocation_start; 3619 guest_offset = old_length; 3620 while (nb_new_data_clusters) { 3621 int64_t nb_clusters = MIN( 3622 nb_new_data_clusters, 3623 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3624 QCowL2Meta allocation = { 3625 .offset = guest_offset, 3626 .alloc_offset = host_offset, 3627 .nb_clusters = nb_clusters, 3628 }; 3629 qemu_co_queue_init(&allocation.dependent_requests); 3630 3631 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3632 if (ret < 0) { 3633 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3634 qcow2_free_clusters(bs, host_offset, 3635 nb_new_data_clusters * s->cluster_size, 3636 QCOW2_DISCARD_OTHER); 3637 return ret; 3638 } 3639 3640 guest_offset += nb_clusters * s->cluster_size; 3641 host_offset += nb_clusters * s->cluster_size; 3642 nb_new_data_clusters -= nb_clusters; 3643 } 3644 break; 3645 } 3646 3647 default: 3648 g_assert_not_reached(); 3649 } 3650 3651 if (prealloc != PREALLOC_MODE_OFF) { 3652 /* Flush metadata before actually changing the image size */ 3653 ret = bdrv_flush(bs); 3654 if (ret < 0) { 3655 error_setg_errno(errp, -ret, 3656 "Failed to flush the preallocated area to disk"); 3657 return ret; 3658 } 3659 } 3660 3661 /* write updated header.size */ 3662 offset = cpu_to_be64(offset); 3663 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3664 &offset, sizeof(uint64_t)); 3665 if (ret < 0) { 3666 error_setg_errno(errp, -ret, "Failed to update the image size"); 3667 return ret; 3668 } 3669 3670 s->l1_vm_state_index = new_l1_size; 3671 return 0; 3672 } 3673 3674 /* XXX: put compressed sectors first, then all the cluster aligned 3675 tables to avoid losing bytes in alignment */ 3676 static coroutine_fn int 3677 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 3678 uint64_t bytes, QEMUIOVector *qiov) 3679 { 3680 BDRVQcow2State *s = bs->opaque; 3681 QEMUIOVector hd_qiov; 3682 struct iovec iov; 3683 z_stream strm; 3684 int ret, out_len; 3685 uint8_t *buf, *out_buf; 3686 int64_t cluster_offset; 3687 3688 if (bytes == 0) { 3689 /* align end of file to a sector boundary to ease reading with 3690 sector based I/Os */ 3691 cluster_offset = bdrv_getlength(bs->file->bs); 3692 if (cluster_offset < 0) { 3693 return cluster_offset; 3694 } 3695 return bdrv_truncate(bs->file, cluster_offset, PREALLOC_MODE_OFF, NULL); 3696 } 3697 3698 if (offset_into_cluster(s, offset)) { 3699 return -EINVAL; 3700 } 3701 3702 buf = qemu_blockalign(bs, s->cluster_size); 3703 if (bytes != s->cluster_size) { 3704 if (bytes > s->cluster_size || 3705 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 3706 { 3707 qemu_vfree(buf); 3708 return -EINVAL; 3709 } 3710 /* Zero-pad last write if image size is not cluster aligned */ 3711 memset(buf + bytes, 0, s->cluster_size - bytes); 3712 } 3713 qemu_iovec_to_buf(qiov, 0, buf, bytes); 3714 3715 out_buf = g_malloc(s->cluster_size); 3716 3717 /* best compression, small window, no zlib header */ 3718 memset(&strm, 0, sizeof(strm)); 3719 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 3720 Z_DEFLATED, -12, 3721 9, Z_DEFAULT_STRATEGY); 3722 if (ret != 0) { 3723 ret = -EINVAL; 3724 goto fail; 3725 } 3726 3727 strm.avail_in = s->cluster_size; 3728 strm.next_in = (uint8_t *)buf; 3729 strm.avail_out = s->cluster_size; 3730 strm.next_out = out_buf; 3731 3732 ret = deflate(&strm, Z_FINISH); 3733 if (ret != Z_STREAM_END && ret != Z_OK) { 3734 deflateEnd(&strm); 3735 ret = -EINVAL; 3736 goto fail; 3737 } 3738 out_len = strm.next_out - out_buf; 3739 3740 deflateEnd(&strm); 3741 3742 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 3743 /* could not compress: write normal cluster */ 3744 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 3745 if (ret < 0) { 3746 goto fail; 3747 } 3748 goto success; 3749 } 3750 3751 qemu_co_mutex_lock(&s->lock); 3752 cluster_offset = 3753 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); 3754 if (!cluster_offset) { 3755 qemu_co_mutex_unlock(&s->lock); 3756 ret = -EIO; 3757 goto fail; 3758 } 3759 cluster_offset &= s->cluster_offset_mask; 3760 3761 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 3762 qemu_co_mutex_unlock(&s->lock); 3763 if (ret < 0) { 3764 goto fail; 3765 } 3766 3767 iov = (struct iovec) { 3768 .iov_base = out_buf, 3769 .iov_len = out_len, 3770 }; 3771 qemu_iovec_init_external(&hd_qiov, &iov, 1); 3772 3773 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 3774 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 3775 if (ret < 0) { 3776 goto fail; 3777 } 3778 success: 3779 ret = 0; 3780 fail: 3781 qemu_vfree(buf); 3782 g_free(out_buf); 3783 return ret; 3784 } 3785 3786 static int make_completely_empty(BlockDriverState *bs) 3787 { 3788 BDRVQcow2State *s = bs->opaque; 3789 Error *local_err = NULL; 3790 int ret, l1_clusters; 3791 int64_t offset; 3792 uint64_t *new_reftable = NULL; 3793 uint64_t rt_entry, l1_size2; 3794 struct { 3795 uint64_t l1_offset; 3796 uint64_t reftable_offset; 3797 uint32_t reftable_clusters; 3798 } QEMU_PACKED l1_ofs_rt_ofs_cls; 3799 3800 ret = qcow2_cache_empty(bs, s->l2_table_cache); 3801 if (ret < 0) { 3802 goto fail; 3803 } 3804 3805 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 3806 if (ret < 0) { 3807 goto fail; 3808 } 3809 3810 /* Refcounts will be broken utterly */ 3811 ret = qcow2_mark_dirty(bs); 3812 if (ret < 0) { 3813 goto fail; 3814 } 3815 3816 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 3817 3818 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 3819 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 3820 3821 /* After this call, neither the in-memory nor the on-disk refcount 3822 * information accurately describe the actual references */ 3823 3824 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 3825 l1_clusters * s->cluster_size, 0); 3826 if (ret < 0) { 3827 goto fail_broken_refcounts; 3828 } 3829 memset(s->l1_table, 0, l1_size2); 3830 3831 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 3832 3833 /* Overwrite enough clusters at the beginning of the sectors to place 3834 * the refcount table, a refcount block and the L1 table in; this may 3835 * overwrite parts of the existing refcount and L1 table, which is not 3836 * an issue because the dirty flag is set, complete data loss is in fact 3837 * desired and partial data loss is consequently fine as well */ 3838 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 3839 (2 + l1_clusters) * s->cluster_size, 0); 3840 /* This call (even if it failed overall) may have overwritten on-disk 3841 * refcount structures; in that case, the in-memory refcount information 3842 * will probably differ from the on-disk information which makes the BDS 3843 * unusable */ 3844 if (ret < 0) { 3845 goto fail_broken_refcounts; 3846 } 3847 3848 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 3849 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 3850 3851 /* "Create" an empty reftable (one cluster) directly after the image 3852 * header and an empty L1 table three clusters after the image header; 3853 * the cluster between those two will be used as the first refblock */ 3854 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 3855 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 3856 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 3857 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 3858 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 3859 if (ret < 0) { 3860 goto fail_broken_refcounts; 3861 } 3862 3863 s->l1_table_offset = 3 * s->cluster_size; 3864 3865 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 3866 if (!new_reftable) { 3867 ret = -ENOMEM; 3868 goto fail_broken_refcounts; 3869 } 3870 3871 s->refcount_table_offset = s->cluster_size; 3872 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 3873 s->max_refcount_table_index = 0; 3874 3875 g_free(s->refcount_table); 3876 s->refcount_table = new_reftable; 3877 new_reftable = NULL; 3878 3879 /* Now the in-memory refcount information again corresponds to the on-disk 3880 * information (reftable is empty and no refblocks (the refblock cache is 3881 * empty)); however, this means some clusters (e.g. the image header) are 3882 * referenced, but not refcounted, but the normal qcow2 code assumes that 3883 * the in-memory information is always correct */ 3884 3885 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 3886 3887 /* Enter the first refblock into the reftable */ 3888 rt_entry = cpu_to_be64(2 * s->cluster_size); 3889 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 3890 &rt_entry, sizeof(rt_entry)); 3891 if (ret < 0) { 3892 goto fail_broken_refcounts; 3893 } 3894 s->refcount_table[0] = 2 * s->cluster_size; 3895 3896 s->free_cluster_index = 0; 3897 assert(3 + l1_clusters <= s->refcount_block_size); 3898 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 3899 if (offset < 0) { 3900 ret = offset; 3901 goto fail_broken_refcounts; 3902 } else if (offset > 0) { 3903 error_report("First cluster in emptied image is in use"); 3904 abort(); 3905 } 3906 3907 /* Now finally the in-memory information corresponds to the on-disk 3908 * structures and is correct */ 3909 ret = qcow2_mark_clean(bs); 3910 if (ret < 0) { 3911 goto fail; 3912 } 3913 3914 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 3915 PREALLOC_MODE_OFF, &local_err); 3916 if (ret < 0) { 3917 error_report_err(local_err); 3918 goto fail; 3919 } 3920 3921 return 0; 3922 3923 fail_broken_refcounts: 3924 /* The BDS is unusable at this point. If we wanted to make it usable, we 3925 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 3926 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 3927 * again. However, because the functions which could have caused this error 3928 * path to be taken are used by those functions as well, it's very likely 3929 * that that sequence will fail as well. Therefore, just eject the BDS. */ 3930 bs->drv = NULL; 3931 3932 fail: 3933 g_free(new_reftable); 3934 return ret; 3935 } 3936 3937 static int qcow2_make_empty(BlockDriverState *bs) 3938 { 3939 BDRVQcow2State *s = bs->opaque; 3940 uint64_t offset, end_offset; 3941 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 3942 int l1_clusters, ret = 0; 3943 3944 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 3945 3946 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 3947 3 + l1_clusters <= s->refcount_block_size && 3948 s->crypt_method_header != QCOW_CRYPT_LUKS) { 3949 /* The following function only works for qcow2 v3 images (it 3950 * requires the dirty flag) and only as long as there are no 3951 * features that reserve extra clusters (such as snapshots, 3952 * LUKS header, or persistent bitmaps), because it completely 3953 * empties the image. Furthermore, the L1 table and three 3954 * additional clusters (image header, refcount table, one 3955 * refcount block) have to fit inside one refcount block. */ 3956 return make_completely_empty(bs); 3957 } 3958 3959 /* This fallback code simply discards every active cluster; this is slow, 3960 * but works in all cases */ 3961 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 3962 for (offset = 0; offset < end_offset; offset += step) { 3963 /* As this function is generally used after committing an external 3964 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 3965 * default action for this kind of discard is to pass the discard, 3966 * which will ideally result in an actually smaller image file, as 3967 * is probably desired. */ 3968 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 3969 QCOW2_DISCARD_SNAPSHOT, true); 3970 if (ret < 0) { 3971 break; 3972 } 3973 } 3974 3975 return ret; 3976 } 3977 3978 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 3979 { 3980 BDRVQcow2State *s = bs->opaque; 3981 int ret; 3982 3983 qemu_co_mutex_lock(&s->lock); 3984 ret = qcow2_write_caches(bs); 3985 qemu_co_mutex_unlock(&s->lock); 3986 3987 return ret; 3988 } 3989 3990 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 3991 Error **errp) 3992 { 3993 Error *local_err = NULL; 3994 BlockMeasureInfo *info; 3995 uint64_t required = 0; /* bytes that contribute to required size */ 3996 uint64_t virtual_size; /* disk size as seen by guest */ 3997 uint64_t refcount_bits; 3998 uint64_t l2_tables; 3999 size_t cluster_size; 4000 int version; 4001 char *optstr; 4002 PreallocMode prealloc; 4003 bool has_backing_file; 4004 4005 /* Parse image creation options */ 4006 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 4007 if (local_err) { 4008 goto err; 4009 } 4010 4011 version = qcow2_opt_get_version_del(opts, &local_err); 4012 if (local_err) { 4013 goto err; 4014 } 4015 4016 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 4017 if (local_err) { 4018 goto err; 4019 } 4020 4021 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 4022 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 4023 PREALLOC_MODE_OFF, &local_err); 4024 g_free(optstr); 4025 if (local_err) { 4026 goto err; 4027 } 4028 4029 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 4030 has_backing_file = !!optstr; 4031 g_free(optstr); 4032 4033 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 4034 virtual_size = ROUND_UP(virtual_size, cluster_size); 4035 4036 /* Check that virtual disk size is valid */ 4037 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 4038 cluster_size / sizeof(uint64_t)); 4039 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 4040 error_setg(&local_err, "The image size is too large " 4041 "(try using a larger cluster size)"); 4042 goto err; 4043 } 4044 4045 /* Account for input image */ 4046 if (in_bs) { 4047 int64_t ssize = bdrv_getlength(in_bs); 4048 if (ssize < 0) { 4049 error_setg_errno(&local_err, -ssize, 4050 "Unable to get image virtual_size"); 4051 goto err; 4052 } 4053 4054 virtual_size = ROUND_UP(ssize, cluster_size); 4055 4056 if (has_backing_file) { 4057 /* We don't how much of the backing chain is shared by the input 4058 * image and the new image file. In the worst case the new image's 4059 * backing file has nothing in common with the input image. Be 4060 * conservative and assume all clusters need to be written. 4061 */ 4062 required = virtual_size; 4063 } else { 4064 int64_t offset; 4065 int64_t pnum = 0; 4066 4067 for (offset = 0; offset < ssize; offset += pnum) { 4068 int ret; 4069 4070 ret = bdrv_block_status_above(in_bs, NULL, offset, 4071 ssize - offset, &pnum, NULL, 4072 NULL); 4073 if (ret < 0) { 4074 error_setg_errno(&local_err, -ret, 4075 "Unable to get block status"); 4076 goto err; 4077 } 4078 4079 if (ret & BDRV_BLOCK_ZERO) { 4080 /* Skip zero regions (safe with no backing file) */ 4081 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 4082 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 4083 /* Extend pnum to end of cluster for next iteration */ 4084 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 4085 4086 /* Count clusters we've seen */ 4087 required += offset % cluster_size + pnum; 4088 } 4089 } 4090 } 4091 } 4092 4093 /* Take into account preallocation. Nothing special is needed for 4094 * PREALLOC_MODE_METADATA since metadata is always counted. 4095 */ 4096 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 4097 required = virtual_size; 4098 } 4099 4100 info = g_new(BlockMeasureInfo, 1); 4101 info->fully_allocated = 4102 qcow2_calc_prealloc_size(virtual_size, cluster_size, 4103 ctz32(refcount_bits)); 4104 4105 /* Remove data clusters that are not required. This overestimates the 4106 * required size because metadata needed for the fully allocated file is 4107 * still counted. 4108 */ 4109 info->required = info->fully_allocated - virtual_size + required; 4110 return info; 4111 4112 err: 4113 error_propagate(errp, local_err); 4114 return NULL; 4115 } 4116 4117 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4118 { 4119 BDRVQcow2State *s = bs->opaque; 4120 bdi->unallocated_blocks_are_zero = true; 4121 bdi->cluster_size = s->cluster_size; 4122 bdi->vm_state_offset = qcow2_vm_state_offset(s); 4123 return 0; 4124 } 4125 4126 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 4127 { 4128 BDRVQcow2State *s = bs->opaque; 4129 ImageInfoSpecific *spec_info; 4130 QCryptoBlockInfo *encrypt_info = NULL; 4131 4132 if (s->crypto != NULL) { 4133 encrypt_info = qcrypto_block_get_info(s->crypto, &error_abort); 4134 } 4135 4136 spec_info = g_new(ImageInfoSpecific, 1); 4137 *spec_info = (ImageInfoSpecific){ 4138 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 4139 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 4140 }; 4141 if (s->qcow_version == 2) { 4142 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4143 .compat = g_strdup("0.10"), 4144 .refcount_bits = s->refcount_bits, 4145 }; 4146 } else if (s->qcow_version == 3) { 4147 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4148 .compat = g_strdup("1.1"), 4149 .lazy_refcounts = s->compatible_features & 4150 QCOW2_COMPAT_LAZY_REFCOUNTS, 4151 .has_lazy_refcounts = true, 4152 .corrupt = s->incompatible_features & 4153 QCOW2_INCOMPAT_CORRUPT, 4154 .has_corrupt = true, 4155 .refcount_bits = s->refcount_bits, 4156 }; 4157 } else { 4158 /* if this assertion fails, this probably means a new version was 4159 * added without having it covered here */ 4160 assert(false); 4161 } 4162 4163 if (encrypt_info) { 4164 ImageInfoSpecificQCow2Encryption *qencrypt = 4165 g_new(ImageInfoSpecificQCow2Encryption, 1); 4166 switch (encrypt_info->format) { 4167 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 4168 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 4169 break; 4170 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 4171 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 4172 qencrypt->u.luks = encrypt_info->u.luks; 4173 break; 4174 default: 4175 abort(); 4176 } 4177 /* Since we did shallow copy above, erase any pointers 4178 * in the original info */ 4179 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 4180 qapi_free_QCryptoBlockInfo(encrypt_info); 4181 4182 spec_info->u.qcow2.data->has_encrypt = true; 4183 spec_info->u.qcow2.data->encrypt = qencrypt; 4184 } 4185 4186 return spec_info; 4187 } 4188 4189 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4190 int64_t pos) 4191 { 4192 BDRVQcow2State *s = bs->opaque; 4193 4194 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 4195 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 4196 qiov->size, qiov, 0); 4197 } 4198 4199 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4200 int64_t pos) 4201 { 4202 BDRVQcow2State *s = bs->opaque; 4203 4204 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 4205 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 4206 qiov->size, qiov, 0); 4207 } 4208 4209 /* 4210 * Downgrades an image's version. To achieve this, any incompatible features 4211 * have to be removed. 4212 */ 4213 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 4214 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 4215 Error **errp) 4216 { 4217 BDRVQcow2State *s = bs->opaque; 4218 int current_version = s->qcow_version; 4219 int ret; 4220 4221 /* This is qcow2_downgrade(), not qcow2_upgrade() */ 4222 assert(target_version < current_version); 4223 4224 /* There are no other versions (now) that you can downgrade to */ 4225 assert(target_version == 2); 4226 4227 if (s->refcount_order != 4) { 4228 error_setg(errp, "compat=0.10 requires refcount_bits=16"); 4229 return -ENOTSUP; 4230 } 4231 4232 /* clear incompatible features */ 4233 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 4234 ret = qcow2_mark_clean(bs); 4235 if (ret < 0) { 4236 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4237 return ret; 4238 } 4239 } 4240 4241 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 4242 * the first place; if that happens nonetheless, returning -ENOTSUP is the 4243 * best thing to do anyway */ 4244 4245 if (s->incompatible_features) { 4246 error_setg(errp, "Cannot downgrade an image with incompatible features " 4247 "%#" PRIx64 " set", s->incompatible_features); 4248 return -ENOTSUP; 4249 } 4250 4251 /* since we can ignore compatible features, we can set them to 0 as well */ 4252 s->compatible_features = 0; 4253 /* if lazy refcounts have been used, they have already been fixed through 4254 * clearing the dirty flag */ 4255 4256 /* clearing autoclear features is trivial */ 4257 s->autoclear_features = 0; 4258 4259 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 4260 if (ret < 0) { 4261 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); 4262 return ret; 4263 } 4264 4265 s->qcow_version = target_version; 4266 ret = qcow2_update_header(bs); 4267 if (ret < 0) { 4268 s->qcow_version = current_version; 4269 error_setg_errno(errp, -ret, "Failed to update the image header"); 4270 return ret; 4271 } 4272 return 0; 4273 } 4274 4275 typedef enum Qcow2AmendOperation { 4276 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 4277 * statically initialized to so that the helper CB can discern the first 4278 * invocation from an operation change */ 4279 QCOW2_NO_OPERATION = 0, 4280 4281 QCOW2_CHANGING_REFCOUNT_ORDER, 4282 QCOW2_DOWNGRADING, 4283 } Qcow2AmendOperation; 4284 4285 typedef struct Qcow2AmendHelperCBInfo { 4286 /* The code coordinating the amend operations should only modify 4287 * these four fields; the rest will be managed by the CB */ 4288 BlockDriverAmendStatusCB *original_status_cb; 4289 void *original_cb_opaque; 4290 4291 Qcow2AmendOperation current_operation; 4292 4293 /* Total number of operations to perform (only set once) */ 4294 int total_operations; 4295 4296 /* The following fields are managed by the CB */ 4297 4298 /* Number of operations completed */ 4299 int operations_completed; 4300 4301 /* Cumulative offset of all completed operations */ 4302 int64_t offset_completed; 4303 4304 Qcow2AmendOperation last_operation; 4305 int64_t last_work_size; 4306 } Qcow2AmendHelperCBInfo; 4307 4308 static void qcow2_amend_helper_cb(BlockDriverState *bs, 4309 int64_t operation_offset, 4310 int64_t operation_work_size, void *opaque) 4311 { 4312 Qcow2AmendHelperCBInfo *info = opaque; 4313 int64_t current_work_size; 4314 int64_t projected_work_size; 4315 4316 if (info->current_operation != info->last_operation) { 4317 if (info->last_operation != QCOW2_NO_OPERATION) { 4318 info->offset_completed += info->last_work_size; 4319 info->operations_completed++; 4320 } 4321 4322 info->last_operation = info->current_operation; 4323 } 4324 4325 assert(info->total_operations > 0); 4326 assert(info->operations_completed < info->total_operations); 4327 4328 info->last_work_size = operation_work_size; 4329 4330 current_work_size = info->offset_completed + operation_work_size; 4331 4332 /* current_work_size is the total work size for (operations_completed + 1) 4333 * operations (which includes this one), so multiply it by the number of 4334 * operations not covered and divide it by the number of operations 4335 * covered to get a projection for the operations not covered */ 4336 projected_work_size = current_work_size * (info->total_operations - 4337 info->operations_completed - 1) 4338 / (info->operations_completed + 1); 4339 4340 info->original_status_cb(bs, info->offset_completed + operation_offset, 4341 current_work_size + projected_work_size, 4342 info->original_cb_opaque); 4343 } 4344 4345 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4346 BlockDriverAmendStatusCB *status_cb, 4347 void *cb_opaque, 4348 Error **errp) 4349 { 4350 BDRVQcow2State *s = bs->opaque; 4351 int old_version = s->qcow_version, new_version = old_version; 4352 uint64_t new_size = 0; 4353 const char *backing_file = NULL, *backing_format = NULL; 4354 bool lazy_refcounts = s->use_lazy_refcounts; 4355 const char *compat = NULL; 4356 uint64_t cluster_size = s->cluster_size; 4357 bool encrypt; 4358 int encformat; 4359 int refcount_bits = s->refcount_bits; 4360 int ret; 4361 QemuOptDesc *desc = opts->list->desc; 4362 Qcow2AmendHelperCBInfo helper_cb_info; 4363 4364 while (desc && desc->name) { 4365 if (!qemu_opt_find(opts, desc->name)) { 4366 /* only change explicitly defined options */ 4367 desc++; 4368 continue; 4369 } 4370 4371 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4372 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4373 if (!compat) { 4374 /* preserve default */ 4375 } else if (!strcmp(compat, "0.10")) { 4376 new_version = 2; 4377 } else if (!strcmp(compat, "1.1")) { 4378 new_version = 3; 4379 } else { 4380 error_setg(errp, "Unknown compatibility level %s", compat); 4381 return -EINVAL; 4382 } 4383 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4384 error_setg(errp, "Cannot change preallocation mode"); 4385 return -ENOTSUP; 4386 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4387 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4388 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4389 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4390 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4391 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4392 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4393 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4394 !!s->crypto); 4395 4396 if (encrypt != !!s->crypto) { 4397 error_setg(errp, 4398 "Changing the encryption flag is not supported"); 4399 return -ENOTSUP; 4400 } 4401 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4402 encformat = qcow2_crypt_method_from_format( 4403 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4404 4405 if (encformat != s->crypt_method_header) { 4406 error_setg(errp, 4407 "Changing the encryption format is not supported"); 4408 return -ENOTSUP; 4409 } 4410 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4411 error_setg(errp, 4412 "Changing the encryption parameters is not supported"); 4413 return -ENOTSUP; 4414 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4415 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4416 cluster_size); 4417 if (cluster_size != s->cluster_size) { 4418 error_setg(errp, "Changing the cluster size is not supported"); 4419 return -ENOTSUP; 4420 } 4421 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4422 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4423 lazy_refcounts); 4424 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4425 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4426 refcount_bits); 4427 4428 if (refcount_bits <= 0 || refcount_bits > 64 || 4429 !is_power_of_2(refcount_bits)) 4430 { 4431 error_setg(errp, "Refcount width must be a power of two and " 4432 "may not exceed 64 bits"); 4433 return -EINVAL; 4434 } 4435 } else { 4436 /* if this point is reached, this probably means a new option was 4437 * added without having it covered here */ 4438 abort(); 4439 } 4440 4441 desc++; 4442 } 4443 4444 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4445 .original_status_cb = status_cb, 4446 .original_cb_opaque = cb_opaque, 4447 .total_operations = (new_version < old_version) 4448 + (s->refcount_bits != refcount_bits) 4449 }; 4450 4451 /* Upgrade first (some features may require compat=1.1) */ 4452 if (new_version > old_version) { 4453 s->qcow_version = new_version; 4454 ret = qcow2_update_header(bs); 4455 if (ret < 0) { 4456 s->qcow_version = old_version; 4457 error_setg_errno(errp, -ret, "Failed to update the image header"); 4458 return ret; 4459 } 4460 } 4461 4462 if (s->refcount_bits != refcount_bits) { 4463 int refcount_order = ctz32(refcount_bits); 4464 4465 if (new_version < 3 && refcount_bits != 16) { 4466 error_setg(errp, "Refcount widths other than 16 bits require " 4467 "compatibility level 1.1 or above (use compat=1.1 or " 4468 "greater)"); 4469 return -EINVAL; 4470 } 4471 4472 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4473 ret = qcow2_change_refcount_order(bs, refcount_order, 4474 &qcow2_amend_helper_cb, 4475 &helper_cb_info, errp); 4476 if (ret < 0) { 4477 return ret; 4478 } 4479 } 4480 4481 if (backing_file || backing_format) { 4482 ret = qcow2_change_backing_file(bs, 4483 backing_file ?: s->image_backing_file, 4484 backing_format ?: s->image_backing_format); 4485 if (ret < 0) { 4486 error_setg_errno(errp, -ret, "Failed to change the backing file"); 4487 return ret; 4488 } 4489 } 4490 4491 if (s->use_lazy_refcounts != lazy_refcounts) { 4492 if (lazy_refcounts) { 4493 if (new_version < 3) { 4494 error_setg(errp, "Lazy refcounts only supported with " 4495 "compatibility level 1.1 and above (use compat=1.1 " 4496 "or greater)"); 4497 return -EINVAL; 4498 } 4499 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4500 ret = qcow2_update_header(bs); 4501 if (ret < 0) { 4502 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4503 error_setg_errno(errp, -ret, "Failed to update the image header"); 4504 return ret; 4505 } 4506 s->use_lazy_refcounts = true; 4507 } else { 4508 /* make image clean first */ 4509 ret = qcow2_mark_clean(bs); 4510 if (ret < 0) { 4511 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4512 return ret; 4513 } 4514 /* now disallow lazy refcounts */ 4515 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4516 ret = qcow2_update_header(bs); 4517 if (ret < 0) { 4518 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4519 error_setg_errno(errp, -ret, "Failed to update the image header"); 4520 return ret; 4521 } 4522 s->use_lazy_refcounts = false; 4523 } 4524 } 4525 4526 if (new_size) { 4527 BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); 4528 ret = blk_insert_bs(blk, bs, errp); 4529 if (ret < 0) { 4530 blk_unref(blk); 4531 return ret; 4532 } 4533 4534 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp); 4535 blk_unref(blk); 4536 if (ret < 0) { 4537 return ret; 4538 } 4539 } 4540 4541 /* Downgrade last (so unsupported features can be removed before) */ 4542 if (new_version < old_version) { 4543 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 4544 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 4545 &helper_cb_info, errp); 4546 if (ret < 0) { 4547 return ret; 4548 } 4549 } 4550 4551 return 0; 4552 } 4553 4554 /* 4555 * If offset or size are negative, respectively, they will not be included in 4556 * the BLOCK_IMAGE_CORRUPTED event emitted. 4557 * fatal will be ignored for read-only BDS; corruptions found there will always 4558 * be considered non-fatal. 4559 */ 4560 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 4561 int64_t size, const char *message_format, ...) 4562 { 4563 BDRVQcow2State *s = bs->opaque; 4564 const char *node_name; 4565 char *message; 4566 va_list ap; 4567 4568 fatal = fatal && bdrv_is_writable(bs); 4569 4570 if (s->signaled_corruption && 4571 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 4572 { 4573 return; 4574 } 4575 4576 va_start(ap, message_format); 4577 message = g_strdup_vprintf(message_format, ap); 4578 va_end(ap); 4579 4580 if (fatal) { 4581 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 4582 "corruption events will be suppressed\n", message); 4583 } else { 4584 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 4585 "corruption events will be suppressed\n", message); 4586 } 4587 4588 node_name = bdrv_get_node_name(bs); 4589 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 4590 *node_name != '\0', node_name, 4591 message, offset >= 0, offset, 4592 size >= 0, size, 4593 fatal, &error_abort); 4594 g_free(message); 4595 4596 if (fatal) { 4597 qcow2_mark_corrupt(bs); 4598 bs->drv = NULL; /* make BDS unusable */ 4599 } 4600 4601 s->signaled_corruption = true; 4602 } 4603 4604 static QemuOptsList qcow2_create_opts = { 4605 .name = "qcow2-create-opts", 4606 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 4607 .desc = { 4608 { 4609 .name = BLOCK_OPT_SIZE, 4610 .type = QEMU_OPT_SIZE, 4611 .help = "Virtual disk size" 4612 }, 4613 { 4614 .name = BLOCK_OPT_COMPAT_LEVEL, 4615 .type = QEMU_OPT_STRING, 4616 .help = "Compatibility level (0.10 or 1.1)" 4617 }, 4618 { 4619 .name = BLOCK_OPT_BACKING_FILE, 4620 .type = QEMU_OPT_STRING, 4621 .help = "File name of a base image" 4622 }, 4623 { 4624 .name = BLOCK_OPT_BACKING_FMT, 4625 .type = QEMU_OPT_STRING, 4626 .help = "Image format of the base image" 4627 }, 4628 { 4629 .name = BLOCK_OPT_ENCRYPT, 4630 .type = QEMU_OPT_BOOL, 4631 .help = "Encrypt the image with format 'aes'. (Deprecated " 4632 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 4633 }, 4634 { 4635 .name = BLOCK_OPT_ENCRYPT_FORMAT, 4636 .type = QEMU_OPT_STRING, 4637 .help = "Encrypt the image, format choices: 'aes', 'luks'", 4638 }, 4639 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 4640 "ID of secret providing qcow AES key or LUKS passphrase"), 4641 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 4642 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 4643 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 4644 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 4645 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 4646 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 4647 { 4648 .name = BLOCK_OPT_CLUSTER_SIZE, 4649 .type = QEMU_OPT_SIZE, 4650 .help = "qcow2 cluster size", 4651 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 4652 }, 4653 { 4654 .name = BLOCK_OPT_PREALLOC, 4655 .type = QEMU_OPT_STRING, 4656 .help = "Preallocation mode (allowed values: off, metadata, " 4657 "falloc, full)" 4658 }, 4659 { 4660 .name = BLOCK_OPT_LAZY_REFCOUNTS, 4661 .type = QEMU_OPT_BOOL, 4662 .help = "Postpone refcount updates", 4663 .def_value_str = "off" 4664 }, 4665 { 4666 .name = BLOCK_OPT_REFCOUNT_BITS, 4667 .type = QEMU_OPT_NUMBER, 4668 .help = "Width of a reference count entry in bits", 4669 .def_value_str = "16" 4670 }, 4671 { /* end of list */ } 4672 } 4673 }; 4674 4675 BlockDriver bdrv_qcow2 = { 4676 .format_name = "qcow2", 4677 .instance_size = sizeof(BDRVQcow2State), 4678 .bdrv_probe = qcow2_probe, 4679 .bdrv_open = qcow2_open, 4680 .bdrv_close = qcow2_close, 4681 .bdrv_reopen_prepare = qcow2_reopen_prepare, 4682 .bdrv_reopen_commit = qcow2_reopen_commit, 4683 .bdrv_reopen_abort = qcow2_reopen_abort, 4684 .bdrv_join_options = qcow2_join_options, 4685 .bdrv_child_perm = bdrv_format_default_perms, 4686 .bdrv_co_create_opts = qcow2_co_create_opts, 4687 .bdrv_co_create = qcow2_co_create, 4688 .bdrv_has_zero_init = bdrv_has_zero_init_1, 4689 .bdrv_co_block_status = qcow2_co_block_status, 4690 4691 .bdrv_co_preadv = qcow2_co_preadv, 4692 .bdrv_co_pwritev = qcow2_co_pwritev, 4693 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 4694 4695 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 4696 .bdrv_co_pdiscard = qcow2_co_pdiscard, 4697 .bdrv_co_copy_range_from = qcow2_co_copy_range_from, 4698 .bdrv_co_copy_range_to = qcow2_co_copy_range_to, 4699 .bdrv_truncate = qcow2_truncate, 4700 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 4701 .bdrv_make_empty = qcow2_make_empty, 4702 4703 .bdrv_snapshot_create = qcow2_snapshot_create, 4704 .bdrv_snapshot_goto = qcow2_snapshot_goto, 4705 .bdrv_snapshot_delete = qcow2_snapshot_delete, 4706 .bdrv_snapshot_list = qcow2_snapshot_list, 4707 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 4708 .bdrv_measure = qcow2_measure, 4709 .bdrv_get_info = qcow2_get_info, 4710 .bdrv_get_specific_info = qcow2_get_specific_info, 4711 4712 .bdrv_save_vmstate = qcow2_save_vmstate, 4713 .bdrv_load_vmstate = qcow2_load_vmstate, 4714 4715 .supports_backing = true, 4716 .bdrv_change_backing_file = qcow2_change_backing_file, 4717 4718 .bdrv_refresh_limits = qcow2_refresh_limits, 4719 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, 4720 .bdrv_inactivate = qcow2_inactivate, 4721 4722 .create_opts = &qcow2_create_opts, 4723 .bdrv_co_check = qcow2_co_check, 4724 .bdrv_amend_options = qcow2_amend_options, 4725 4726 .bdrv_detach_aio_context = qcow2_detach_aio_context, 4727 .bdrv_attach_aio_context = qcow2_attach_aio_context, 4728 4729 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 4730 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 4731 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 4732 }; 4733 4734 static void bdrv_qcow2_init(void) 4735 { 4736 bdrv_register(&bdrv_qcow2); 4737 } 4738 4739 block_init(bdrv_qcow2_init); 4740