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 27 #include "block/qdict.h" 28 #include "sysemu/block-backend.h" 29 #include "qemu/module.h" 30 #include "qcow2.h" 31 #include "qemu/error-report.h" 32 #include "qapi/error.h" 33 #include "qapi/qapi-events-block-core.h" 34 #include "qapi/qmp/qdict.h" 35 #include "qapi/qmp/qstring.h" 36 #include "trace.h" 37 #include "qemu/option_int.h" 38 #include "qemu/cutils.h" 39 #include "qemu/bswap.h" 40 #include "qapi/qobject-input-visitor.h" 41 #include "qapi/qapi-visit-block-core.h" 42 #include "crypto.h" 43 44 /* 45 Differences with QCOW: 46 47 - Support for multiple incremental snapshots. 48 - Memory management by reference counts. 49 - Clusters which have a reference count of one have the bit 50 QCOW_OFLAG_COPIED to optimize write performance. 51 - Size of compressed clusters is stored in sectors to reduce bit usage 52 in the cluster offsets. 53 - Support for storing additional data (such as the VM state) in the 54 snapshots. 55 - If a backing store is used, the cluster size is not constrained 56 (could be backported to QCOW). 57 - L2 tables have always a size of one cluster. 58 */ 59 60 61 typedef struct { 62 uint32_t magic; 63 uint32_t len; 64 } QEMU_PACKED QCowExtension; 65 66 #define QCOW2_EXT_MAGIC_END 0 67 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 68 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 69 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 70 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 71 #define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441 72 73 static int coroutine_fn 74 qcow2_co_preadv_compressed(BlockDriverState *bs, 75 uint64_t file_cluster_offset, 76 uint64_t offset, 77 uint64_t bytes, 78 QEMUIOVector *qiov); 79 80 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 81 { 82 const QCowHeader *cow_header = (const void *)buf; 83 84 if (buf_size >= sizeof(QCowHeader) && 85 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 86 be32_to_cpu(cow_header->version) >= 2) 87 return 100; 88 else 89 return 0; 90 } 91 92 93 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 94 uint8_t *buf, size_t buflen, 95 void *opaque, Error **errp) 96 { 97 BlockDriverState *bs = opaque; 98 BDRVQcow2State *s = bs->opaque; 99 ssize_t ret; 100 101 if ((offset + buflen) > s->crypto_header.length) { 102 error_setg(errp, "Request for data outside of extension header"); 103 return -1; 104 } 105 106 ret = bdrv_pread(bs->file, 107 s->crypto_header.offset + offset, buf, buflen); 108 if (ret < 0) { 109 error_setg_errno(errp, -ret, "Could not read encryption header"); 110 return -1; 111 } 112 return ret; 113 } 114 115 116 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 117 void *opaque, Error **errp) 118 { 119 BlockDriverState *bs = opaque; 120 BDRVQcow2State *s = bs->opaque; 121 int64_t ret; 122 int64_t clusterlen; 123 124 ret = qcow2_alloc_clusters(bs, headerlen); 125 if (ret < 0) { 126 error_setg_errno(errp, -ret, 127 "Cannot allocate cluster for LUKS header size %zu", 128 headerlen); 129 return -1; 130 } 131 132 s->crypto_header.length = headerlen; 133 s->crypto_header.offset = ret; 134 135 /* Zero fill remaining space in cluster so it has predictable 136 * content in case of future spec changes */ 137 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 138 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0); 139 ret = bdrv_pwrite_zeroes(bs->file, 140 ret + headerlen, 141 clusterlen - headerlen, 0); 142 if (ret < 0) { 143 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 144 return -1; 145 } 146 147 return ret; 148 } 149 150 151 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 152 const uint8_t *buf, size_t buflen, 153 void *opaque, Error **errp) 154 { 155 BlockDriverState *bs = opaque; 156 BDRVQcow2State *s = bs->opaque; 157 ssize_t ret; 158 159 if ((offset + buflen) > s->crypto_header.length) { 160 error_setg(errp, "Request for data outside of extension header"); 161 return -1; 162 } 163 164 ret = bdrv_pwrite(bs->file, 165 s->crypto_header.offset + offset, buf, buflen); 166 if (ret < 0) { 167 error_setg_errno(errp, -ret, "Could not read encryption header"); 168 return -1; 169 } 170 return ret; 171 } 172 173 174 /* 175 * read qcow2 extension and fill bs 176 * start reading from start_offset 177 * finish reading upon magic of value 0 or when end_offset reached 178 * unknown magic is skipped (future extension this version knows nothing about) 179 * return 0 upon success, non-0 otherwise 180 */ 181 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 182 uint64_t end_offset, void **p_feature_table, 183 int flags, bool *need_update_header, 184 Error **errp) 185 { 186 BDRVQcow2State *s = bs->opaque; 187 QCowExtension ext; 188 uint64_t offset; 189 int ret; 190 Qcow2BitmapHeaderExt bitmaps_ext; 191 192 if (need_update_header != NULL) { 193 *need_update_header = false; 194 } 195 196 #ifdef DEBUG_EXT 197 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 198 #endif 199 offset = start_offset; 200 while (offset < end_offset) { 201 202 #ifdef DEBUG_EXT 203 /* Sanity check */ 204 if (offset > s->cluster_size) 205 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 206 207 printf("attempting to read extended header in offset %lu\n", offset); 208 #endif 209 210 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 211 if (ret < 0) { 212 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 213 "pread fail from offset %" PRIu64, offset); 214 return 1; 215 } 216 ext.magic = be32_to_cpu(ext.magic); 217 ext.len = be32_to_cpu(ext.len); 218 offset += sizeof(ext); 219 #ifdef DEBUG_EXT 220 printf("ext.magic = 0x%x\n", ext.magic); 221 #endif 222 if (offset > end_offset || ext.len > end_offset - offset) { 223 error_setg(errp, "Header extension too large"); 224 return -EINVAL; 225 } 226 227 switch (ext.magic) { 228 case QCOW2_EXT_MAGIC_END: 229 return 0; 230 231 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 232 if (ext.len >= sizeof(bs->backing_format)) { 233 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 234 " too large (>=%zu)", ext.len, 235 sizeof(bs->backing_format)); 236 return 2; 237 } 238 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 239 if (ret < 0) { 240 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 241 "Could not read format name"); 242 return 3; 243 } 244 bs->backing_format[ext.len] = '\0'; 245 s->image_backing_format = g_strdup(bs->backing_format); 246 #ifdef DEBUG_EXT 247 printf("Qcow2: Got format extension %s\n", bs->backing_format); 248 #endif 249 break; 250 251 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 252 if (p_feature_table != NULL) { 253 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 254 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 255 if (ret < 0) { 256 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 257 "Could not read table"); 258 return ret; 259 } 260 261 *p_feature_table = feature_table; 262 } 263 break; 264 265 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 266 unsigned int cflags = 0; 267 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 268 error_setg(errp, "CRYPTO header extension only " 269 "expected with LUKS encryption method"); 270 return -EINVAL; 271 } 272 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 273 error_setg(errp, "CRYPTO header extension size %u, " 274 "but expected size %zu", ext.len, 275 sizeof(Qcow2CryptoHeaderExtension)); 276 return -EINVAL; 277 } 278 279 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 280 if (ret < 0) { 281 error_setg_errno(errp, -ret, 282 "Unable to read CRYPTO header extension"); 283 return ret; 284 } 285 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 286 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 287 288 if ((s->crypto_header.offset % s->cluster_size) != 0) { 289 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 290 "not a multiple of cluster size '%u'", 291 s->crypto_header.offset, s->cluster_size); 292 return -EINVAL; 293 } 294 295 if (flags & BDRV_O_NO_IO) { 296 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 297 } 298 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 299 qcow2_crypto_hdr_read_func, 300 bs, cflags, QCOW2_MAX_THREADS, errp); 301 if (!s->crypto) { 302 return -EINVAL; 303 } 304 } break; 305 306 case QCOW2_EXT_MAGIC_BITMAPS: 307 if (ext.len != sizeof(bitmaps_ext)) { 308 error_setg_errno(errp, -ret, "bitmaps_ext: " 309 "Invalid extension length"); 310 return -EINVAL; 311 } 312 313 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 314 if (s->qcow_version < 3) { 315 /* Let's be a bit more specific */ 316 warn_report("This qcow2 v2 image contains bitmaps, but " 317 "they may have been modified by a program " 318 "without persistent bitmap support; so now " 319 "they must all be considered inconsistent"); 320 } else { 321 warn_report("a program lacking bitmap support " 322 "modified this file, so all bitmaps are now " 323 "considered inconsistent"); 324 } 325 error_printf("Some clusters may be leaked, " 326 "run 'qemu-img check -r' on the image " 327 "file to fix."); 328 if (need_update_header != NULL) { 329 /* Updating is needed to drop invalid bitmap extension. */ 330 *need_update_header = true; 331 } 332 break; 333 } 334 335 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 336 if (ret < 0) { 337 error_setg_errno(errp, -ret, "bitmaps_ext: " 338 "Could not read ext header"); 339 return ret; 340 } 341 342 if (bitmaps_ext.reserved32 != 0) { 343 error_setg_errno(errp, -ret, "bitmaps_ext: " 344 "Reserved field is not zero"); 345 return -EINVAL; 346 } 347 348 bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps); 349 bitmaps_ext.bitmap_directory_size = 350 be64_to_cpu(bitmaps_ext.bitmap_directory_size); 351 bitmaps_ext.bitmap_directory_offset = 352 be64_to_cpu(bitmaps_ext.bitmap_directory_offset); 353 354 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 355 error_setg(errp, 356 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 357 "exceeding the QEMU supported maximum of %d", 358 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 359 return -EINVAL; 360 } 361 362 if (bitmaps_ext.nb_bitmaps == 0) { 363 error_setg(errp, "found bitmaps extension with zero bitmaps"); 364 return -EINVAL; 365 } 366 367 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 368 error_setg(errp, "bitmaps_ext: " 369 "invalid bitmap directory offset"); 370 return -EINVAL; 371 } 372 373 if (bitmaps_ext.bitmap_directory_size > 374 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 375 error_setg(errp, "bitmaps_ext: " 376 "bitmap directory size (%" PRIu64 ") exceeds " 377 "the maximum supported size (%d)", 378 bitmaps_ext.bitmap_directory_size, 379 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 380 return -EINVAL; 381 } 382 383 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 384 s->bitmap_directory_offset = 385 bitmaps_ext.bitmap_directory_offset; 386 s->bitmap_directory_size = 387 bitmaps_ext.bitmap_directory_size; 388 389 #ifdef DEBUG_EXT 390 printf("Qcow2: Got bitmaps extension: " 391 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 392 s->bitmap_directory_offset, s->nb_bitmaps); 393 #endif 394 break; 395 396 case QCOW2_EXT_MAGIC_DATA_FILE: 397 { 398 s->image_data_file = g_malloc0(ext.len + 1); 399 ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len); 400 if (ret < 0) { 401 error_setg_errno(errp, -ret, 402 "ERROR: Could not read data file name"); 403 return ret; 404 } 405 #ifdef DEBUG_EXT 406 printf("Qcow2: Got external data file %s\n", s->image_data_file); 407 #endif 408 break; 409 } 410 411 default: 412 /* unknown magic - save it in case we need to rewrite the header */ 413 /* If you add a new feature, make sure to also update the fast 414 * path of qcow2_make_empty() to deal with it. */ 415 { 416 Qcow2UnknownHeaderExtension *uext; 417 418 uext = g_malloc0(sizeof(*uext) + ext.len); 419 uext->magic = ext.magic; 420 uext->len = ext.len; 421 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 422 423 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 424 if (ret < 0) { 425 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 426 "Could not read data"); 427 return ret; 428 } 429 } 430 break; 431 } 432 433 offset += ((ext.len + 7) & ~7); 434 } 435 436 return 0; 437 } 438 439 static void cleanup_unknown_header_ext(BlockDriverState *bs) 440 { 441 BDRVQcow2State *s = bs->opaque; 442 Qcow2UnknownHeaderExtension *uext, *next; 443 444 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 445 QLIST_REMOVE(uext, next); 446 g_free(uext); 447 } 448 } 449 450 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 451 uint64_t mask) 452 { 453 char *features = g_strdup(""); 454 char *old; 455 456 while (table && table->name[0] != '\0') { 457 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 458 if (mask & (1ULL << table->bit)) { 459 old = features; 460 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 461 table->name); 462 g_free(old); 463 mask &= ~(1ULL << table->bit); 464 } 465 } 466 table++; 467 } 468 469 if (mask) { 470 old = features; 471 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 472 old, *old ? ", " : "", mask); 473 g_free(old); 474 } 475 476 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 477 g_free(features); 478 } 479 480 /* 481 * Sets the dirty bit and flushes afterwards if necessary. 482 * 483 * The incompatible_features bit is only set if the image file header was 484 * updated successfully. Therefore it is not required to check the return 485 * value of this function. 486 */ 487 int qcow2_mark_dirty(BlockDriverState *bs) 488 { 489 BDRVQcow2State *s = bs->opaque; 490 uint64_t val; 491 int ret; 492 493 assert(s->qcow_version >= 3); 494 495 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 496 return 0; /* already dirty */ 497 } 498 499 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 500 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 501 &val, sizeof(val)); 502 if (ret < 0) { 503 return ret; 504 } 505 ret = bdrv_flush(bs->file->bs); 506 if (ret < 0) { 507 return ret; 508 } 509 510 /* Only treat image as dirty if the header was updated successfully */ 511 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 512 return 0; 513 } 514 515 /* 516 * Clears the dirty bit and flushes before if necessary. Only call this 517 * function when there are no pending requests, it does not guard against 518 * concurrent requests dirtying the image. 519 */ 520 static int qcow2_mark_clean(BlockDriverState *bs) 521 { 522 BDRVQcow2State *s = bs->opaque; 523 524 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 525 int ret; 526 527 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 528 529 ret = qcow2_flush_caches(bs); 530 if (ret < 0) { 531 return ret; 532 } 533 534 return qcow2_update_header(bs); 535 } 536 return 0; 537 } 538 539 /* 540 * Marks the image as corrupt. 541 */ 542 int qcow2_mark_corrupt(BlockDriverState *bs) 543 { 544 BDRVQcow2State *s = bs->opaque; 545 546 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 547 return qcow2_update_header(bs); 548 } 549 550 /* 551 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 552 * before if necessary. 553 */ 554 int qcow2_mark_consistent(BlockDriverState *bs) 555 { 556 BDRVQcow2State *s = bs->opaque; 557 558 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 559 int ret = qcow2_flush_caches(bs); 560 if (ret < 0) { 561 return ret; 562 } 563 564 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 565 return qcow2_update_header(bs); 566 } 567 return 0; 568 } 569 570 static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, 571 BdrvCheckResult *result, 572 BdrvCheckMode fix) 573 { 574 int ret = qcow2_check_refcounts(bs, result, fix); 575 if (ret < 0) { 576 return ret; 577 } 578 579 if (fix && result->check_errors == 0 && result->corruptions == 0) { 580 ret = qcow2_mark_clean(bs); 581 if (ret < 0) { 582 return ret; 583 } 584 return qcow2_mark_consistent(bs); 585 } 586 return ret; 587 } 588 589 static int coroutine_fn qcow2_co_check(BlockDriverState *bs, 590 BdrvCheckResult *result, 591 BdrvCheckMode fix) 592 { 593 BDRVQcow2State *s = bs->opaque; 594 int ret; 595 596 qemu_co_mutex_lock(&s->lock); 597 ret = qcow2_co_check_locked(bs, result, fix); 598 qemu_co_mutex_unlock(&s->lock); 599 return ret; 600 } 601 602 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, 603 uint64_t entries, size_t entry_len, 604 int64_t max_size_bytes, const char *table_name, 605 Error **errp) 606 { 607 BDRVQcow2State *s = bs->opaque; 608 609 if (entries > max_size_bytes / entry_len) { 610 error_setg(errp, "%s too large", table_name); 611 return -EFBIG; 612 } 613 614 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 615 * because values will be passed to qemu functions taking int64_t. */ 616 if ((INT64_MAX - entries * entry_len < offset) || 617 (offset_into_cluster(s, offset) != 0)) { 618 error_setg(errp, "%s offset invalid", table_name); 619 return -EINVAL; 620 } 621 622 return 0; 623 } 624 625 static const char *const mutable_opts[] = { 626 QCOW2_OPT_LAZY_REFCOUNTS, 627 QCOW2_OPT_DISCARD_REQUEST, 628 QCOW2_OPT_DISCARD_SNAPSHOT, 629 QCOW2_OPT_DISCARD_OTHER, 630 QCOW2_OPT_OVERLAP, 631 QCOW2_OPT_OVERLAP_TEMPLATE, 632 QCOW2_OPT_OVERLAP_MAIN_HEADER, 633 QCOW2_OPT_OVERLAP_ACTIVE_L1, 634 QCOW2_OPT_OVERLAP_ACTIVE_L2, 635 QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 636 QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 637 QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 638 QCOW2_OPT_OVERLAP_INACTIVE_L1, 639 QCOW2_OPT_OVERLAP_INACTIVE_L2, 640 QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 641 QCOW2_OPT_CACHE_SIZE, 642 QCOW2_OPT_L2_CACHE_SIZE, 643 QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 644 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 645 QCOW2_OPT_CACHE_CLEAN_INTERVAL, 646 NULL 647 }; 648 649 static QemuOptsList qcow2_runtime_opts = { 650 .name = "qcow2", 651 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 652 .desc = { 653 { 654 .name = QCOW2_OPT_LAZY_REFCOUNTS, 655 .type = QEMU_OPT_BOOL, 656 .help = "Postpone refcount updates", 657 }, 658 { 659 .name = QCOW2_OPT_DISCARD_REQUEST, 660 .type = QEMU_OPT_BOOL, 661 .help = "Pass guest discard requests to the layer below", 662 }, 663 { 664 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 665 .type = QEMU_OPT_BOOL, 666 .help = "Generate discard requests when snapshot related space " 667 "is freed", 668 }, 669 { 670 .name = QCOW2_OPT_DISCARD_OTHER, 671 .type = QEMU_OPT_BOOL, 672 .help = "Generate discard requests when other clusters are freed", 673 }, 674 { 675 .name = QCOW2_OPT_OVERLAP, 676 .type = QEMU_OPT_STRING, 677 .help = "Selects which overlap checks to perform from a range of " 678 "templates (none, constant, cached, all)", 679 }, 680 { 681 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 682 .type = QEMU_OPT_STRING, 683 .help = "Selects which overlap checks to perform from a range of " 684 "templates (none, constant, cached, all)", 685 }, 686 { 687 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 688 .type = QEMU_OPT_BOOL, 689 .help = "Check for unintended writes into the main qcow2 header", 690 }, 691 { 692 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 693 .type = QEMU_OPT_BOOL, 694 .help = "Check for unintended writes into the active L1 table", 695 }, 696 { 697 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 698 .type = QEMU_OPT_BOOL, 699 .help = "Check for unintended writes into an active L2 table", 700 }, 701 { 702 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 703 .type = QEMU_OPT_BOOL, 704 .help = "Check for unintended writes into the refcount table", 705 }, 706 { 707 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 708 .type = QEMU_OPT_BOOL, 709 .help = "Check for unintended writes into a refcount block", 710 }, 711 { 712 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 713 .type = QEMU_OPT_BOOL, 714 .help = "Check for unintended writes into the snapshot table", 715 }, 716 { 717 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 718 .type = QEMU_OPT_BOOL, 719 .help = "Check for unintended writes into an inactive L1 table", 720 }, 721 { 722 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 723 .type = QEMU_OPT_BOOL, 724 .help = "Check for unintended writes into an inactive L2 table", 725 }, 726 { 727 .name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 728 .type = QEMU_OPT_BOOL, 729 .help = "Check for unintended writes into the bitmap directory", 730 }, 731 { 732 .name = QCOW2_OPT_CACHE_SIZE, 733 .type = QEMU_OPT_SIZE, 734 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 735 "cache size", 736 }, 737 { 738 .name = QCOW2_OPT_L2_CACHE_SIZE, 739 .type = QEMU_OPT_SIZE, 740 .help = "Maximum L2 table cache size", 741 }, 742 { 743 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 744 .type = QEMU_OPT_SIZE, 745 .help = "Size of each entry in the L2 cache", 746 }, 747 { 748 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 749 .type = QEMU_OPT_SIZE, 750 .help = "Maximum refcount block cache size", 751 }, 752 { 753 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 754 .type = QEMU_OPT_NUMBER, 755 .help = "Clean unused cache entries after this time (in seconds)", 756 }, 757 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 758 "ID of secret providing qcow2 AES key or LUKS passphrase"), 759 { /* end of list */ } 760 }, 761 }; 762 763 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 764 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 765 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 766 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 767 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 768 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 769 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 770 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 771 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 772 [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 773 }; 774 775 static void cache_clean_timer_cb(void *opaque) 776 { 777 BlockDriverState *bs = opaque; 778 BDRVQcow2State *s = bs->opaque; 779 qcow2_cache_clean_unused(s->l2_table_cache); 780 qcow2_cache_clean_unused(s->refcount_block_cache); 781 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 782 (int64_t) s->cache_clean_interval * 1000); 783 } 784 785 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 786 { 787 BDRVQcow2State *s = bs->opaque; 788 if (s->cache_clean_interval > 0) { 789 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 790 SCALE_MS, cache_clean_timer_cb, 791 bs); 792 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 793 (int64_t) s->cache_clean_interval * 1000); 794 } 795 } 796 797 static void cache_clean_timer_del(BlockDriverState *bs) 798 { 799 BDRVQcow2State *s = bs->opaque; 800 if (s->cache_clean_timer) { 801 timer_del(s->cache_clean_timer); 802 timer_free(s->cache_clean_timer); 803 s->cache_clean_timer = NULL; 804 } 805 } 806 807 static void qcow2_detach_aio_context(BlockDriverState *bs) 808 { 809 cache_clean_timer_del(bs); 810 } 811 812 static void qcow2_attach_aio_context(BlockDriverState *bs, 813 AioContext *new_context) 814 { 815 cache_clean_timer_init(bs, new_context); 816 } 817 818 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 819 uint64_t *l2_cache_size, 820 uint64_t *l2_cache_entry_size, 821 uint64_t *refcount_cache_size, Error **errp) 822 { 823 BDRVQcow2State *s = bs->opaque; 824 uint64_t combined_cache_size, l2_cache_max_setting; 825 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 826 bool l2_cache_entry_size_set; 827 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; 828 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; 829 uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8); 830 831 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 832 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 833 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 834 l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE); 835 836 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 837 l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 838 DEFAULT_L2_CACHE_MAX_SIZE); 839 *refcount_cache_size = qemu_opt_get_size(opts, 840 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 841 842 *l2_cache_entry_size = qemu_opt_get_size( 843 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 844 845 *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting); 846 847 if (combined_cache_size_set) { 848 if (l2_cache_size_set && refcount_cache_size_set) { 849 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 850 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 851 "at the same time"); 852 return; 853 } else if (l2_cache_size_set && 854 (l2_cache_max_setting > combined_cache_size)) { 855 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 856 QCOW2_OPT_CACHE_SIZE); 857 return; 858 } else if (*refcount_cache_size > combined_cache_size) { 859 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 860 QCOW2_OPT_CACHE_SIZE); 861 return; 862 } 863 864 if (l2_cache_size_set) { 865 *refcount_cache_size = combined_cache_size - *l2_cache_size; 866 } else if (refcount_cache_size_set) { 867 *l2_cache_size = combined_cache_size - *refcount_cache_size; 868 } else { 869 /* Assign as much memory as possible to the L2 cache, and 870 * use the remainder for the refcount cache */ 871 if (combined_cache_size >= max_l2_cache + min_refcount_cache) { 872 *l2_cache_size = max_l2_cache; 873 *refcount_cache_size = combined_cache_size - *l2_cache_size; 874 } else { 875 *refcount_cache_size = 876 MIN(combined_cache_size, min_refcount_cache); 877 *l2_cache_size = combined_cache_size - *refcount_cache_size; 878 } 879 } 880 } 881 882 /* 883 * If the L2 cache is not enough to cover the whole disk then 884 * default to 4KB entries. Smaller entries reduce the cost of 885 * loads and evictions and increase I/O performance. 886 */ 887 if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) { 888 *l2_cache_entry_size = MIN(s->cluster_size, 4096); 889 } 890 891 /* l2_cache_size and refcount_cache_size are ensured to have at least 892 * their minimum values in qcow2_update_options_prepare() */ 893 894 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 895 *l2_cache_entry_size > s->cluster_size || 896 !is_power_of_2(*l2_cache_entry_size)) { 897 error_setg(errp, "L2 cache entry size must be a power of two " 898 "between %d and the cluster size (%d)", 899 1 << MIN_CLUSTER_BITS, s->cluster_size); 900 return; 901 } 902 } 903 904 typedef struct Qcow2ReopenState { 905 Qcow2Cache *l2_table_cache; 906 Qcow2Cache *refcount_block_cache; 907 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 908 bool use_lazy_refcounts; 909 int overlap_check; 910 bool discard_passthrough[QCOW2_DISCARD_MAX]; 911 uint64_t cache_clean_interval; 912 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 913 } Qcow2ReopenState; 914 915 static int qcow2_update_options_prepare(BlockDriverState *bs, 916 Qcow2ReopenState *r, 917 QDict *options, int flags, 918 Error **errp) 919 { 920 BDRVQcow2State *s = bs->opaque; 921 QemuOpts *opts = NULL; 922 const char *opt_overlap_check, *opt_overlap_check_template; 923 int overlap_check_template = 0; 924 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 925 int i; 926 const char *encryptfmt; 927 QDict *encryptopts = NULL; 928 Error *local_err = NULL; 929 int ret; 930 931 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 932 encryptfmt = qdict_get_try_str(encryptopts, "format"); 933 934 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 935 qemu_opts_absorb_qdict(opts, options, &local_err); 936 if (local_err) { 937 error_propagate(errp, local_err); 938 ret = -EINVAL; 939 goto fail; 940 } 941 942 /* get L2 table/refcount block cache size from command line options */ 943 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 944 &refcount_cache_size, &local_err); 945 if (local_err) { 946 error_propagate(errp, local_err); 947 ret = -EINVAL; 948 goto fail; 949 } 950 951 l2_cache_size /= l2_cache_entry_size; 952 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 953 l2_cache_size = MIN_L2_CACHE_SIZE; 954 } 955 if (l2_cache_size > INT_MAX) { 956 error_setg(errp, "L2 cache size too big"); 957 ret = -EINVAL; 958 goto fail; 959 } 960 961 refcount_cache_size /= s->cluster_size; 962 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 963 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 964 } 965 if (refcount_cache_size > INT_MAX) { 966 error_setg(errp, "Refcount cache size too big"); 967 ret = -EINVAL; 968 goto fail; 969 } 970 971 /* alloc new L2 table/refcount block cache, flush old one */ 972 if (s->l2_table_cache) { 973 ret = qcow2_cache_flush(bs, s->l2_table_cache); 974 if (ret) { 975 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 976 goto fail; 977 } 978 } 979 980 if (s->refcount_block_cache) { 981 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 982 if (ret) { 983 error_setg_errno(errp, -ret, 984 "Failed to flush the refcount block cache"); 985 goto fail; 986 } 987 } 988 989 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 990 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 991 l2_cache_entry_size); 992 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 993 s->cluster_size); 994 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 995 error_setg(errp, "Could not allocate metadata caches"); 996 ret = -ENOMEM; 997 goto fail; 998 } 999 1000 /* New interval for cache cleanup timer */ 1001 r->cache_clean_interval = 1002 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 1003 DEFAULT_CACHE_CLEAN_INTERVAL); 1004 #ifndef CONFIG_LINUX 1005 if (r->cache_clean_interval != 0) { 1006 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 1007 " not supported on this host"); 1008 ret = -EINVAL; 1009 goto fail; 1010 } 1011 #endif 1012 if (r->cache_clean_interval > UINT_MAX) { 1013 error_setg(errp, "Cache clean interval too big"); 1014 ret = -EINVAL; 1015 goto fail; 1016 } 1017 1018 /* lazy-refcounts; flush if going from enabled to disabled */ 1019 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 1020 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 1021 if (r->use_lazy_refcounts && s->qcow_version < 3) { 1022 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 1023 "qemu 1.1 compatibility level"); 1024 ret = -EINVAL; 1025 goto fail; 1026 } 1027 1028 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 1029 ret = qcow2_mark_clean(bs); 1030 if (ret < 0) { 1031 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 1032 goto fail; 1033 } 1034 } 1035 1036 /* Overlap check options */ 1037 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 1038 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 1039 if (opt_overlap_check_template && opt_overlap_check && 1040 strcmp(opt_overlap_check_template, opt_overlap_check)) 1041 { 1042 error_setg(errp, "Conflicting values for qcow2 options '" 1043 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 1044 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 1045 ret = -EINVAL; 1046 goto fail; 1047 } 1048 if (!opt_overlap_check) { 1049 opt_overlap_check = opt_overlap_check_template ?: "cached"; 1050 } 1051 1052 if (!strcmp(opt_overlap_check, "none")) { 1053 overlap_check_template = 0; 1054 } else if (!strcmp(opt_overlap_check, "constant")) { 1055 overlap_check_template = QCOW2_OL_CONSTANT; 1056 } else if (!strcmp(opt_overlap_check, "cached")) { 1057 overlap_check_template = QCOW2_OL_CACHED; 1058 } else if (!strcmp(opt_overlap_check, "all")) { 1059 overlap_check_template = QCOW2_OL_ALL; 1060 } else { 1061 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1062 "'overlap-check'. Allowed are any of the following: " 1063 "none, constant, cached, all", opt_overlap_check); 1064 ret = -EINVAL; 1065 goto fail; 1066 } 1067 1068 r->overlap_check = 0; 1069 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1070 /* overlap-check defines a template bitmask, but every flag may be 1071 * overwritten through the associated boolean option */ 1072 r->overlap_check |= 1073 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1074 overlap_check_template & (1 << i)) << i; 1075 } 1076 1077 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 1078 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1079 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1080 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1081 flags & BDRV_O_UNMAP); 1082 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1083 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1084 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1085 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1086 1087 switch (s->crypt_method_header) { 1088 case QCOW_CRYPT_NONE: 1089 if (encryptfmt) { 1090 error_setg(errp, "No encryption in image header, but options " 1091 "specified format '%s'", encryptfmt); 1092 ret = -EINVAL; 1093 goto fail; 1094 } 1095 break; 1096 1097 case QCOW_CRYPT_AES: 1098 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1099 error_setg(errp, 1100 "Header reported 'aes' encryption format but " 1101 "options specify '%s'", encryptfmt); 1102 ret = -EINVAL; 1103 goto fail; 1104 } 1105 qdict_put_str(encryptopts, "format", "qcow"); 1106 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1107 break; 1108 1109 case QCOW_CRYPT_LUKS: 1110 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1111 error_setg(errp, 1112 "Header reported 'luks' encryption format but " 1113 "options specify '%s'", encryptfmt); 1114 ret = -EINVAL; 1115 goto fail; 1116 } 1117 qdict_put_str(encryptopts, "format", "luks"); 1118 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1119 break; 1120 1121 default: 1122 error_setg(errp, "Unsupported encryption method %d", 1123 s->crypt_method_header); 1124 break; 1125 } 1126 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1127 ret = -EINVAL; 1128 goto fail; 1129 } 1130 1131 ret = 0; 1132 fail: 1133 qobject_unref(encryptopts); 1134 qemu_opts_del(opts); 1135 opts = NULL; 1136 return ret; 1137 } 1138 1139 static void qcow2_update_options_commit(BlockDriverState *bs, 1140 Qcow2ReopenState *r) 1141 { 1142 BDRVQcow2State *s = bs->opaque; 1143 int i; 1144 1145 if (s->l2_table_cache) { 1146 qcow2_cache_destroy(s->l2_table_cache); 1147 } 1148 if (s->refcount_block_cache) { 1149 qcow2_cache_destroy(s->refcount_block_cache); 1150 } 1151 s->l2_table_cache = r->l2_table_cache; 1152 s->refcount_block_cache = r->refcount_block_cache; 1153 s->l2_slice_size = r->l2_slice_size; 1154 1155 s->overlap_check = r->overlap_check; 1156 s->use_lazy_refcounts = r->use_lazy_refcounts; 1157 1158 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1159 s->discard_passthrough[i] = r->discard_passthrough[i]; 1160 } 1161 1162 if (s->cache_clean_interval != r->cache_clean_interval) { 1163 cache_clean_timer_del(bs); 1164 s->cache_clean_interval = r->cache_clean_interval; 1165 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1166 } 1167 1168 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1169 s->crypto_opts = r->crypto_opts; 1170 } 1171 1172 static void qcow2_update_options_abort(BlockDriverState *bs, 1173 Qcow2ReopenState *r) 1174 { 1175 if (r->l2_table_cache) { 1176 qcow2_cache_destroy(r->l2_table_cache); 1177 } 1178 if (r->refcount_block_cache) { 1179 qcow2_cache_destroy(r->refcount_block_cache); 1180 } 1181 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1182 } 1183 1184 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1185 int flags, Error **errp) 1186 { 1187 Qcow2ReopenState r = {}; 1188 int ret; 1189 1190 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1191 if (ret >= 0) { 1192 qcow2_update_options_commit(bs, &r); 1193 } else { 1194 qcow2_update_options_abort(bs, &r); 1195 } 1196 1197 return ret; 1198 } 1199 1200 /* Called with s->lock held. */ 1201 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, 1202 int flags, Error **errp) 1203 { 1204 BDRVQcow2State *s = bs->opaque; 1205 unsigned int len, i; 1206 int ret = 0; 1207 QCowHeader header; 1208 Error *local_err = NULL; 1209 uint64_t ext_end; 1210 uint64_t l1_vm_state_index; 1211 bool update_header = false; 1212 1213 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1214 if (ret < 0) { 1215 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1216 goto fail; 1217 } 1218 header.magic = be32_to_cpu(header.magic); 1219 header.version = be32_to_cpu(header.version); 1220 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 1221 header.backing_file_size = be32_to_cpu(header.backing_file_size); 1222 header.size = be64_to_cpu(header.size); 1223 header.cluster_bits = be32_to_cpu(header.cluster_bits); 1224 header.crypt_method = be32_to_cpu(header.crypt_method); 1225 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 1226 header.l1_size = be32_to_cpu(header.l1_size); 1227 header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset); 1228 header.refcount_table_clusters = 1229 be32_to_cpu(header.refcount_table_clusters); 1230 header.snapshots_offset = be64_to_cpu(header.snapshots_offset); 1231 header.nb_snapshots = be32_to_cpu(header.nb_snapshots); 1232 1233 if (header.magic != QCOW_MAGIC) { 1234 error_setg(errp, "Image is not in qcow2 format"); 1235 ret = -EINVAL; 1236 goto fail; 1237 } 1238 if (header.version < 2 || header.version > 3) { 1239 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1240 ret = -ENOTSUP; 1241 goto fail; 1242 } 1243 1244 s->qcow_version = header.version; 1245 1246 /* Initialise cluster size */ 1247 if (header.cluster_bits < MIN_CLUSTER_BITS || 1248 header.cluster_bits > MAX_CLUSTER_BITS) { 1249 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1250 header.cluster_bits); 1251 ret = -EINVAL; 1252 goto fail; 1253 } 1254 1255 s->cluster_bits = header.cluster_bits; 1256 s->cluster_size = 1 << s->cluster_bits; 1257 1258 /* Initialise version 3 header fields */ 1259 if (header.version == 2) { 1260 header.incompatible_features = 0; 1261 header.compatible_features = 0; 1262 header.autoclear_features = 0; 1263 header.refcount_order = 4; 1264 header.header_length = 72; 1265 } else { 1266 header.incompatible_features = 1267 be64_to_cpu(header.incompatible_features); 1268 header.compatible_features = be64_to_cpu(header.compatible_features); 1269 header.autoclear_features = be64_to_cpu(header.autoclear_features); 1270 header.refcount_order = be32_to_cpu(header.refcount_order); 1271 header.header_length = be32_to_cpu(header.header_length); 1272 1273 if (header.header_length < 104) { 1274 error_setg(errp, "qcow2 header too short"); 1275 ret = -EINVAL; 1276 goto fail; 1277 } 1278 } 1279 1280 if (header.header_length > s->cluster_size) { 1281 error_setg(errp, "qcow2 header exceeds cluster size"); 1282 ret = -EINVAL; 1283 goto fail; 1284 } 1285 1286 if (header.header_length > sizeof(header)) { 1287 s->unknown_header_fields_size = header.header_length - sizeof(header); 1288 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1289 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1290 s->unknown_header_fields_size); 1291 if (ret < 0) { 1292 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1293 "fields"); 1294 goto fail; 1295 } 1296 } 1297 1298 if (header.backing_file_offset > s->cluster_size) { 1299 error_setg(errp, "Invalid backing file offset"); 1300 ret = -EINVAL; 1301 goto fail; 1302 } 1303 1304 if (header.backing_file_offset) { 1305 ext_end = header.backing_file_offset; 1306 } else { 1307 ext_end = 1 << header.cluster_bits; 1308 } 1309 1310 /* Handle feature bits */ 1311 s->incompatible_features = header.incompatible_features; 1312 s->compatible_features = header.compatible_features; 1313 s->autoclear_features = header.autoclear_features; 1314 1315 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1316 void *feature_table = NULL; 1317 qcow2_read_extensions(bs, header.header_length, ext_end, 1318 &feature_table, flags, NULL, NULL); 1319 report_unsupported_feature(errp, feature_table, 1320 s->incompatible_features & 1321 ~QCOW2_INCOMPAT_MASK); 1322 ret = -ENOTSUP; 1323 g_free(feature_table); 1324 goto fail; 1325 } 1326 1327 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1328 /* Corrupt images may not be written to unless they are being repaired 1329 */ 1330 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1331 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1332 "read/write"); 1333 ret = -EACCES; 1334 goto fail; 1335 } 1336 } 1337 1338 /* Check support for various header values */ 1339 if (header.refcount_order > 6) { 1340 error_setg(errp, "Reference count entry width too large; may not " 1341 "exceed 64 bits"); 1342 ret = -EINVAL; 1343 goto fail; 1344 } 1345 s->refcount_order = header.refcount_order; 1346 s->refcount_bits = 1 << s->refcount_order; 1347 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1348 s->refcount_max += s->refcount_max - 1; 1349 1350 s->crypt_method_header = header.crypt_method; 1351 if (s->crypt_method_header) { 1352 if (bdrv_uses_whitelist() && 1353 s->crypt_method_header == QCOW_CRYPT_AES) { 1354 error_setg(errp, 1355 "Use of AES-CBC encrypted qcow2 images is no longer " 1356 "supported in system emulators"); 1357 error_append_hint(errp, 1358 "You can use 'qemu-img convert' to convert your " 1359 "image to an alternative supported format, such " 1360 "as unencrypted qcow2, or raw with the LUKS " 1361 "format instead.\n"); 1362 ret = -ENOSYS; 1363 goto fail; 1364 } 1365 1366 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1367 s->crypt_physical_offset = false; 1368 } else { 1369 /* Assuming LUKS and any future crypt methods we 1370 * add will all use physical offsets, due to the 1371 * fact that the alternative is insecure... */ 1372 s->crypt_physical_offset = true; 1373 } 1374 1375 bs->encrypted = true; 1376 } 1377 1378 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1379 s->l2_size = 1 << s->l2_bits; 1380 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1381 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1382 s->refcount_block_size = 1 << s->refcount_block_bits; 1383 bs->total_sectors = header.size / BDRV_SECTOR_SIZE; 1384 s->csize_shift = (62 - (s->cluster_bits - 8)); 1385 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1386 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1387 1388 s->refcount_table_offset = header.refcount_table_offset; 1389 s->refcount_table_size = 1390 header.refcount_table_clusters << (s->cluster_bits - 3); 1391 1392 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1393 error_setg(errp, "Image does not contain a reference count table"); 1394 ret = -EINVAL; 1395 goto fail; 1396 } 1397 1398 ret = qcow2_validate_table(bs, s->refcount_table_offset, 1399 header.refcount_table_clusters, 1400 s->cluster_size, QCOW_MAX_REFTABLE_SIZE, 1401 "Reference count table", errp); 1402 if (ret < 0) { 1403 goto fail; 1404 } 1405 1406 /* The total size in bytes of the snapshot table is checked in 1407 * qcow2_read_snapshots() because the size of each snapshot is 1408 * variable and we don't know it yet. 1409 * Here we only check the offset and number of snapshots. */ 1410 ret = qcow2_validate_table(bs, header.snapshots_offset, 1411 header.nb_snapshots, 1412 sizeof(QCowSnapshotHeader), 1413 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, 1414 "Snapshot table", errp); 1415 if (ret < 0) { 1416 goto fail; 1417 } 1418 1419 /* read the level 1 table */ 1420 ret = qcow2_validate_table(bs, header.l1_table_offset, 1421 header.l1_size, sizeof(uint64_t), 1422 QCOW_MAX_L1_SIZE, "Active L1 table", errp); 1423 if (ret < 0) { 1424 goto fail; 1425 } 1426 s->l1_size = header.l1_size; 1427 s->l1_table_offset = header.l1_table_offset; 1428 1429 l1_vm_state_index = size_to_l1(s, header.size); 1430 if (l1_vm_state_index > INT_MAX) { 1431 error_setg(errp, "Image is too big"); 1432 ret = -EFBIG; 1433 goto fail; 1434 } 1435 s->l1_vm_state_index = l1_vm_state_index; 1436 1437 /* the L1 table must contain at least enough entries to put 1438 header.size bytes */ 1439 if (s->l1_size < s->l1_vm_state_index) { 1440 error_setg(errp, "L1 table is too small"); 1441 ret = -EINVAL; 1442 goto fail; 1443 } 1444 1445 if (s->l1_size > 0) { 1446 s->l1_table = qemu_try_blockalign(bs->file->bs, 1447 ROUND_UP(s->l1_size * sizeof(uint64_t), 512)); 1448 if (s->l1_table == NULL) { 1449 error_setg(errp, "Could not allocate L1 table"); 1450 ret = -ENOMEM; 1451 goto fail; 1452 } 1453 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1454 s->l1_size * sizeof(uint64_t)); 1455 if (ret < 0) { 1456 error_setg_errno(errp, -ret, "Could not read L1 table"); 1457 goto fail; 1458 } 1459 for(i = 0;i < s->l1_size; i++) { 1460 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 1461 } 1462 } 1463 1464 /* Parse driver-specific options */ 1465 ret = qcow2_update_options(bs, options, flags, errp); 1466 if (ret < 0) { 1467 goto fail; 1468 } 1469 1470 s->flags = flags; 1471 1472 ret = qcow2_refcount_init(bs); 1473 if (ret != 0) { 1474 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1475 goto fail; 1476 } 1477 1478 QLIST_INIT(&s->cluster_allocs); 1479 QTAILQ_INIT(&s->discards); 1480 1481 /* read qcow2 extensions */ 1482 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1483 flags, &update_header, &local_err)) { 1484 error_propagate(errp, local_err); 1485 ret = -EINVAL; 1486 goto fail; 1487 } 1488 1489 /* Open external data file */ 1490 s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file, 1491 true, &local_err); 1492 if (local_err) { 1493 error_propagate(errp, local_err); 1494 ret = -EINVAL; 1495 goto fail; 1496 } 1497 1498 if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { 1499 if (!s->data_file && s->image_data_file) { 1500 s->data_file = bdrv_open_child(s->image_data_file, options, 1501 "data-file", bs, &child_file, 1502 false, errp); 1503 if (!s->data_file) { 1504 ret = -EINVAL; 1505 goto fail; 1506 } 1507 } 1508 if (!s->data_file) { 1509 error_setg(errp, "'data-file' is required for this image"); 1510 ret = -EINVAL; 1511 goto fail; 1512 } 1513 } else { 1514 if (s->data_file) { 1515 error_setg(errp, "'data-file' can only be set for images with an " 1516 "external data file"); 1517 ret = -EINVAL; 1518 goto fail; 1519 } 1520 1521 s->data_file = bs->file; 1522 1523 if (data_file_is_raw(bs)) { 1524 error_setg(errp, "data-file-raw requires a data file"); 1525 ret = -EINVAL; 1526 goto fail; 1527 } 1528 } 1529 1530 /* qcow2_read_extension may have set up the crypto context 1531 * if the crypt method needs a header region, some methods 1532 * don't need header extensions, so must check here 1533 */ 1534 if (s->crypt_method_header && !s->crypto) { 1535 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1536 unsigned int cflags = 0; 1537 if (flags & BDRV_O_NO_IO) { 1538 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1539 } 1540 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1541 NULL, NULL, cflags, 1542 QCOW2_MAX_THREADS, errp); 1543 if (!s->crypto) { 1544 ret = -EINVAL; 1545 goto fail; 1546 } 1547 } else if (!(flags & BDRV_O_NO_IO)) { 1548 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1549 s->crypt_method_header); 1550 ret = -EINVAL; 1551 goto fail; 1552 } 1553 } 1554 1555 /* read the backing file name */ 1556 if (header.backing_file_offset != 0) { 1557 len = header.backing_file_size; 1558 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1559 len >= sizeof(bs->backing_file)) { 1560 error_setg(errp, "Backing file name too long"); 1561 ret = -EINVAL; 1562 goto fail; 1563 } 1564 ret = bdrv_pread(bs->file, header.backing_file_offset, 1565 bs->auto_backing_file, len); 1566 if (ret < 0) { 1567 error_setg_errno(errp, -ret, "Could not read backing file name"); 1568 goto fail; 1569 } 1570 bs->auto_backing_file[len] = '\0'; 1571 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1572 bs->auto_backing_file); 1573 s->image_backing_file = g_strdup(bs->auto_backing_file); 1574 } 1575 1576 /* Internal snapshots */ 1577 s->snapshots_offset = header.snapshots_offset; 1578 s->nb_snapshots = header.nb_snapshots; 1579 1580 ret = qcow2_read_snapshots(bs); 1581 if (ret < 0) { 1582 error_setg_errno(errp, -ret, "Could not read snapshots"); 1583 goto fail; 1584 } 1585 1586 /* Clear unknown autoclear feature bits */ 1587 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1588 update_header = 1589 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1590 if (update_header) { 1591 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1592 } 1593 1594 /* == Handle persistent dirty bitmaps == 1595 * 1596 * We want load dirty bitmaps in three cases: 1597 * 1598 * 1. Normal open of the disk in active mode, not related to invalidation 1599 * after migration. 1600 * 1601 * 2. Invalidation of the target vm after pre-copy phase of migration, if 1602 * bitmaps are _not_ migrating through migration channel, i.e. 1603 * 'dirty-bitmaps' capability is disabled. 1604 * 1605 * 3. Invalidation of source vm after failed or canceled migration. 1606 * This is a very interesting case. There are two possible types of 1607 * bitmaps: 1608 * 1609 * A. Stored on inactivation and removed. They should be loaded from the 1610 * image. 1611 * 1612 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through 1613 * the migration channel (with dirty-bitmaps capability). 1614 * 1615 * On the other hand, there are two possible sub-cases: 1616 * 1617 * 3.1 disk was changed by somebody else while were inactive. In this 1618 * case all in-RAM dirty bitmaps (both persistent and not) are 1619 * definitely invalid. And we don't have any method to determine 1620 * this. 1621 * 1622 * Simple and safe thing is to just drop all the bitmaps of type B on 1623 * inactivation. But in this case we lose bitmaps in valid 4.2 case. 1624 * 1625 * On the other hand, resuming source vm, if disk was already changed 1626 * is a bad thing anyway: not only bitmaps, the whole vm state is 1627 * out of sync with disk. 1628 * 1629 * This means, that user or management tool, who for some reason 1630 * decided to resume source vm, after disk was already changed by 1631 * target vm, should at least drop all dirty bitmaps by hand. 1632 * 1633 * So, we can ignore this case for now, but TODO: "generation" 1634 * extension for qcow2, to determine, that image was changed after 1635 * last inactivation. And if it is changed, we will drop (or at least 1636 * mark as 'invalid' all the bitmaps of type B, both persistent 1637 * and not). 1638 * 1639 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved 1640 * to disk ('dirty-bitmaps' capability disabled), or not saved 1641 * ('dirty-bitmaps' capability enabled), but we don't need to care 1642 * of: let's load bitmaps as always: stored bitmaps will be loaded, 1643 * and not stored has flag IN_USE=1 in the image and will be skipped 1644 * on loading. 1645 * 1646 * One remaining possible case when we don't want load bitmaps: 1647 * 1648 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or 1649 * will be loaded on invalidation, no needs try loading them before) 1650 */ 1651 1652 if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { 1653 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ 1654 bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); 1655 1656 update_header = update_header && !header_updated; 1657 } 1658 if (local_err != NULL) { 1659 error_propagate(errp, local_err); 1660 ret = -EINVAL; 1661 goto fail; 1662 } 1663 1664 if (update_header) { 1665 ret = qcow2_update_header(bs); 1666 if (ret < 0) { 1667 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1668 goto fail; 1669 } 1670 } 1671 1672 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1673 1674 /* Repair image if dirty */ 1675 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1676 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1677 BdrvCheckResult result = {0}; 1678 1679 ret = qcow2_co_check_locked(bs, &result, 1680 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1681 if (ret < 0 || result.check_errors) { 1682 if (ret >= 0) { 1683 ret = -EIO; 1684 } 1685 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1686 goto fail; 1687 } 1688 } 1689 1690 #ifdef DEBUG_ALLOC 1691 { 1692 BdrvCheckResult result = {0}; 1693 qcow2_check_refcounts(bs, &result, 0); 1694 } 1695 #endif 1696 1697 qemu_co_queue_init(&s->thread_task_queue); 1698 1699 return ret; 1700 1701 fail: 1702 g_free(s->image_data_file); 1703 if (has_data_file(bs)) { 1704 bdrv_unref_child(bs, s->data_file); 1705 } 1706 g_free(s->unknown_header_fields); 1707 cleanup_unknown_header_ext(bs); 1708 qcow2_free_snapshots(bs); 1709 qcow2_refcount_close(bs); 1710 qemu_vfree(s->l1_table); 1711 /* else pre-write overlap checks in cache_destroy may crash */ 1712 s->l1_table = NULL; 1713 cache_clean_timer_del(bs); 1714 if (s->l2_table_cache) { 1715 qcow2_cache_destroy(s->l2_table_cache); 1716 } 1717 if (s->refcount_block_cache) { 1718 qcow2_cache_destroy(s->refcount_block_cache); 1719 } 1720 qcrypto_block_free(s->crypto); 1721 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1722 return ret; 1723 } 1724 1725 typedef struct QCow2OpenCo { 1726 BlockDriverState *bs; 1727 QDict *options; 1728 int flags; 1729 Error **errp; 1730 int ret; 1731 } QCow2OpenCo; 1732 1733 static void coroutine_fn qcow2_open_entry(void *opaque) 1734 { 1735 QCow2OpenCo *qoc = opaque; 1736 BDRVQcow2State *s = qoc->bs->opaque; 1737 1738 qemu_co_mutex_lock(&s->lock); 1739 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); 1740 qemu_co_mutex_unlock(&s->lock); 1741 } 1742 1743 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1744 Error **errp) 1745 { 1746 BDRVQcow2State *s = bs->opaque; 1747 QCow2OpenCo qoc = { 1748 .bs = bs, 1749 .options = options, 1750 .flags = flags, 1751 .errp = errp, 1752 .ret = -EINPROGRESS 1753 }; 1754 1755 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1756 false, errp); 1757 if (!bs->file) { 1758 return -EINVAL; 1759 } 1760 1761 /* Initialise locks */ 1762 qemu_co_mutex_init(&s->lock); 1763 1764 if (qemu_in_coroutine()) { 1765 /* From bdrv_co_create. */ 1766 qcow2_open_entry(&qoc); 1767 } else { 1768 assert(qemu_get_current_aio_context() == qemu_get_aio_context()); 1769 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); 1770 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); 1771 } 1772 return qoc.ret; 1773 } 1774 1775 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1776 { 1777 BDRVQcow2State *s = bs->opaque; 1778 1779 if (bs->encrypted) { 1780 /* Encryption works on a sector granularity */ 1781 bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto); 1782 } 1783 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1784 bs->bl.pdiscard_alignment = s->cluster_size; 1785 } 1786 1787 static int qcow2_reopen_prepare(BDRVReopenState *state, 1788 BlockReopenQueue *queue, Error **errp) 1789 { 1790 Qcow2ReopenState *r; 1791 int ret; 1792 1793 r = g_new0(Qcow2ReopenState, 1); 1794 state->opaque = r; 1795 1796 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1797 state->flags, errp); 1798 if (ret < 0) { 1799 goto fail; 1800 } 1801 1802 /* We need to write out any unwritten data if we reopen read-only. */ 1803 if ((state->flags & BDRV_O_RDWR) == 0) { 1804 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1805 if (ret < 0) { 1806 goto fail; 1807 } 1808 1809 ret = bdrv_flush(state->bs); 1810 if (ret < 0) { 1811 goto fail; 1812 } 1813 1814 ret = qcow2_mark_clean(state->bs); 1815 if (ret < 0) { 1816 goto fail; 1817 } 1818 } 1819 1820 return 0; 1821 1822 fail: 1823 qcow2_update_options_abort(state->bs, r); 1824 g_free(r); 1825 return ret; 1826 } 1827 1828 static void qcow2_reopen_commit(BDRVReopenState *state) 1829 { 1830 qcow2_update_options_commit(state->bs, state->opaque); 1831 g_free(state->opaque); 1832 } 1833 1834 static void qcow2_reopen_abort(BDRVReopenState *state) 1835 { 1836 qcow2_update_options_abort(state->bs, state->opaque); 1837 g_free(state->opaque); 1838 } 1839 1840 static void qcow2_join_options(QDict *options, QDict *old_options) 1841 { 1842 bool has_new_overlap_template = 1843 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1844 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1845 bool has_new_total_cache_size = 1846 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1847 bool has_all_cache_options; 1848 1849 /* New overlap template overrides all old overlap options */ 1850 if (has_new_overlap_template) { 1851 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1852 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1853 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1854 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1855 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1856 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1857 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1858 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1859 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1860 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1861 } 1862 1863 /* New total cache size overrides all old options */ 1864 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1865 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1866 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1867 } 1868 1869 qdict_join(options, old_options, false); 1870 1871 /* 1872 * If after merging all cache size options are set, an old total size is 1873 * overwritten. Do keep all options, however, if all three are new. The 1874 * resulting error message is what we want to happen. 1875 */ 1876 has_all_cache_options = 1877 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1878 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1879 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1880 1881 if (has_all_cache_options && !has_new_total_cache_size) { 1882 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1883 } 1884 } 1885 1886 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, 1887 bool want_zero, 1888 int64_t offset, int64_t count, 1889 int64_t *pnum, int64_t *map, 1890 BlockDriverState **file) 1891 { 1892 BDRVQcow2State *s = bs->opaque; 1893 uint64_t cluster_offset; 1894 int index_in_cluster, ret; 1895 unsigned int bytes; 1896 int status = 0; 1897 1898 bytes = MIN(INT_MAX, count); 1899 qemu_co_mutex_lock(&s->lock); 1900 ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); 1901 qemu_co_mutex_unlock(&s->lock); 1902 if (ret < 0) { 1903 return ret; 1904 } 1905 1906 *pnum = bytes; 1907 1908 if ((ret == QCOW2_CLUSTER_NORMAL || ret == QCOW2_CLUSTER_ZERO_ALLOC) && 1909 !s->crypto) { 1910 index_in_cluster = offset & (s->cluster_size - 1); 1911 *map = cluster_offset | index_in_cluster; 1912 *file = s->data_file->bs; 1913 status |= BDRV_BLOCK_OFFSET_VALID; 1914 } 1915 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1916 status |= BDRV_BLOCK_ZERO; 1917 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1918 status |= BDRV_BLOCK_DATA; 1919 } 1920 return status; 1921 } 1922 1923 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, 1924 QCowL2Meta **pl2meta, 1925 bool link_l2) 1926 { 1927 int ret = 0; 1928 QCowL2Meta *l2meta = *pl2meta; 1929 1930 while (l2meta != NULL) { 1931 QCowL2Meta *next; 1932 1933 if (link_l2) { 1934 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1935 if (ret) { 1936 goto out; 1937 } 1938 } else { 1939 qcow2_alloc_cluster_abort(bs, l2meta); 1940 } 1941 1942 /* Take the request off the list of running requests */ 1943 if (l2meta->nb_clusters != 0) { 1944 QLIST_REMOVE(l2meta, next_in_flight); 1945 } 1946 1947 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1948 1949 next = l2meta->next; 1950 g_free(l2meta); 1951 l2meta = next; 1952 } 1953 out: 1954 *pl2meta = l2meta; 1955 return ret; 1956 } 1957 1958 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1959 uint64_t bytes, QEMUIOVector *qiov, 1960 int flags) 1961 { 1962 BDRVQcow2State *s = bs->opaque; 1963 int offset_in_cluster; 1964 int ret; 1965 unsigned int cur_bytes; /* number of bytes in current iteration */ 1966 uint64_t cluster_offset = 0; 1967 uint64_t bytes_done = 0; 1968 QEMUIOVector hd_qiov; 1969 uint8_t *cluster_data = NULL; 1970 1971 qemu_iovec_init(&hd_qiov, qiov->niov); 1972 1973 while (bytes != 0) { 1974 1975 /* prepare next request */ 1976 cur_bytes = MIN(bytes, INT_MAX); 1977 if (s->crypto) { 1978 cur_bytes = MIN(cur_bytes, 1979 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1980 } 1981 1982 qemu_co_mutex_lock(&s->lock); 1983 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1984 qemu_co_mutex_unlock(&s->lock); 1985 if (ret < 0) { 1986 goto fail; 1987 } 1988 1989 offset_in_cluster = offset_into_cluster(s, offset); 1990 1991 qemu_iovec_reset(&hd_qiov); 1992 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1993 1994 switch (ret) { 1995 case QCOW2_CLUSTER_UNALLOCATED: 1996 1997 if (bs->backing) { 1998 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1999 ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, 2000 &hd_qiov, 0); 2001 if (ret < 0) { 2002 goto fail; 2003 } 2004 } else { 2005 /* Note: in this case, no need to wait */ 2006 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 2007 } 2008 break; 2009 2010 case QCOW2_CLUSTER_ZERO_PLAIN: 2011 case QCOW2_CLUSTER_ZERO_ALLOC: 2012 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 2013 break; 2014 2015 case QCOW2_CLUSTER_COMPRESSED: 2016 ret = qcow2_co_preadv_compressed(bs, cluster_offset, 2017 offset, cur_bytes, 2018 &hd_qiov); 2019 if (ret < 0) { 2020 goto fail; 2021 } 2022 2023 break; 2024 2025 case QCOW2_CLUSTER_NORMAL: 2026 if ((cluster_offset & 511) != 0) { 2027 ret = -EIO; 2028 goto fail; 2029 } 2030 2031 if (bs->encrypted) { 2032 assert(s->crypto); 2033 2034 /* 2035 * For encrypted images, read everything into a temporary 2036 * contiguous buffer on which the AES functions can work. 2037 */ 2038 if (!cluster_data) { 2039 cluster_data = 2040 qemu_try_blockalign(s->data_file->bs, 2041 QCOW_MAX_CRYPT_CLUSTERS 2042 * s->cluster_size); 2043 if (cluster_data == NULL) { 2044 ret = -ENOMEM; 2045 goto fail; 2046 } 2047 } 2048 2049 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2050 qemu_iovec_reset(&hd_qiov); 2051 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 2052 } 2053 2054 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 2055 ret = bdrv_co_preadv(s->data_file, 2056 cluster_offset + offset_in_cluster, 2057 cur_bytes, &hd_qiov, 0); 2058 if (ret < 0) { 2059 goto fail; 2060 } 2061 if (bs->encrypted) { 2062 assert(s->crypto); 2063 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 2064 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 2065 if (qcow2_co_decrypt(bs, cluster_offset, offset, 2066 cluster_data, cur_bytes) < 0) { 2067 ret = -EIO; 2068 goto fail; 2069 } 2070 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 2071 } 2072 break; 2073 2074 default: 2075 g_assert_not_reached(); 2076 ret = -EIO; 2077 goto fail; 2078 } 2079 2080 bytes -= cur_bytes; 2081 offset += cur_bytes; 2082 bytes_done += cur_bytes; 2083 } 2084 ret = 0; 2085 2086 fail: 2087 qemu_iovec_destroy(&hd_qiov); 2088 qemu_vfree(cluster_data); 2089 2090 return ret; 2091 } 2092 2093 /* Check if it's possible to merge a write request with the writing of 2094 * the data from the COW regions */ 2095 static bool merge_cow(uint64_t offset, unsigned bytes, 2096 QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) 2097 { 2098 QCowL2Meta *m; 2099 2100 for (m = l2meta; m != NULL; m = m->next) { 2101 /* If both COW regions are empty then there's nothing to merge */ 2102 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 2103 continue; 2104 } 2105 2106 /* If COW regions are handled already, skip this too */ 2107 if (m->skip_cow) { 2108 continue; 2109 } 2110 2111 /* The data (middle) region must be immediately after the 2112 * start region */ 2113 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 2114 continue; 2115 } 2116 2117 /* The end region must be immediately after the data (middle) 2118 * region */ 2119 if (m->offset + m->cow_end.offset != offset + bytes) { 2120 continue; 2121 } 2122 2123 /* Make sure that adding both COW regions to the QEMUIOVector 2124 * does not exceed IOV_MAX */ 2125 if (hd_qiov->niov > IOV_MAX - 2) { 2126 continue; 2127 } 2128 2129 m->data_qiov = hd_qiov; 2130 return true; 2131 } 2132 2133 return false; 2134 } 2135 2136 static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes) 2137 { 2138 int64_t nr; 2139 return !bytes || 2140 (!bdrv_is_allocated_above(bs, NULL, offset, bytes, &nr) && nr == bytes); 2141 } 2142 2143 static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m) 2144 { 2145 /* 2146 * This check is designed for optimization shortcut so it must be 2147 * efficient. 2148 * Instead of is_zero(), use is_unallocated() as it is faster (but not 2149 * as accurate and can result in false negatives). 2150 */ 2151 return is_unallocated(bs, m->offset + m->cow_start.offset, 2152 m->cow_start.nb_bytes) && 2153 is_unallocated(bs, m->offset + m->cow_end.offset, 2154 m->cow_end.nb_bytes); 2155 } 2156 2157 static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) 2158 { 2159 BDRVQcow2State *s = bs->opaque; 2160 QCowL2Meta *m; 2161 2162 if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) { 2163 return 0; 2164 } 2165 2166 if (bs->encrypted) { 2167 return 0; 2168 } 2169 2170 for (m = l2meta; m != NULL; m = m->next) { 2171 int ret; 2172 2173 if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) { 2174 continue; 2175 } 2176 2177 if (!is_zero_cow(bs, m)) { 2178 continue; 2179 } 2180 2181 /* 2182 * instead of writing zero COW buffers, 2183 * efficiently zero out the whole clusters 2184 */ 2185 2186 ret = qcow2_pre_write_overlap_check(bs, 0, m->alloc_offset, 2187 m->nb_clusters * s->cluster_size, 2188 true); 2189 if (ret < 0) { 2190 return ret; 2191 } 2192 2193 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE); 2194 ret = bdrv_co_pwrite_zeroes(s->data_file, m->alloc_offset, 2195 m->nb_clusters * s->cluster_size, 2196 BDRV_REQ_NO_FALLBACK); 2197 if (ret < 0) { 2198 if (ret != -ENOTSUP && ret != -EAGAIN) { 2199 return ret; 2200 } 2201 continue; 2202 } 2203 2204 trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters); 2205 m->skip_cow = true; 2206 } 2207 return 0; 2208 } 2209 2210 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 2211 uint64_t bytes, QEMUIOVector *qiov, 2212 int flags) 2213 { 2214 BDRVQcow2State *s = bs->opaque; 2215 int offset_in_cluster; 2216 int ret; 2217 unsigned int cur_bytes; /* number of sectors in current iteration */ 2218 uint64_t cluster_offset; 2219 QEMUIOVector hd_qiov; 2220 uint64_t bytes_done = 0; 2221 uint8_t *cluster_data = NULL; 2222 QCowL2Meta *l2meta = NULL; 2223 2224 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 2225 2226 qemu_iovec_init(&hd_qiov, qiov->niov); 2227 2228 qemu_co_mutex_lock(&s->lock); 2229 2230 while (bytes != 0) { 2231 2232 l2meta = NULL; 2233 2234 trace_qcow2_writev_start_part(qemu_coroutine_self()); 2235 offset_in_cluster = offset_into_cluster(s, offset); 2236 cur_bytes = MIN(bytes, INT_MAX); 2237 if (bs->encrypted) { 2238 cur_bytes = MIN(cur_bytes, 2239 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 2240 - offset_in_cluster); 2241 } 2242 2243 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2244 &cluster_offset, &l2meta); 2245 if (ret < 0) { 2246 goto out_locked; 2247 } 2248 2249 assert((cluster_offset & 511) == 0); 2250 2251 ret = qcow2_pre_write_overlap_check(bs, 0, 2252 cluster_offset + offset_in_cluster, 2253 cur_bytes, true); 2254 if (ret < 0) { 2255 goto out_locked; 2256 } 2257 2258 qemu_co_mutex_unlock(&s->lock); 2259 2260 qemu_iovec_reset(&hd_qiov); 2261 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 2262 2263 if (bs->encrypted) { 2264 assert(s->crypto); 2265 if (!cluster_data) { 2266 cluster_data = qemu_try_blockalign(bs->file->bs, 2267 QCOW_MAX_CRYPT_CLUSTERS 2268 * s->cluster_size); 2269 if (cluster_data == NULL) { 2270 ret = -ENOMEM; 2271 goto out_unlocked; 2272 } 2273 } 2274 2275 assert(hd_qiov.size <= 2276 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2277 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 2278 2279 if (qcow2_co_encrypt(bs, cluster_offset, offset, 2280 cluster_data, cur_bytes) < 0) { 2281 ret = -EIO; 2282 goto out_unlocked; 2283 } 2284 2285 qemu_iovec_reset(&hd_qiov); 2286 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 2287 } 2288 2289 /* Try to efficiently initialize the physical space with zeroes */ 2290 ret = handle_alloc_space(bs, l2meta); 2291 if (ret < 0) { 2292 goto out_unlocked; 2293 } 2294 2295 /* If we need to do COW, check if it's possible to merge the 2296 * writing of the guest data together with that of the COW regions. 2297 * If it's not possible (or not necessary) then write the 2298 * guest data now. */ 2299 if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { 2300 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 2301 trace_qcow2_writev_data(qemu_coroutine_self(), 2302 cluster_offset + offset_in_cluster); 2303 ret = bdrv_co_pwritev(s->data_file, 2304 cluster_offset + offset_in_cluster, 2305 cur_bytes, &hd_qiov, 0); 2306 if (ret < 0) { 2307 goto out_unlocked; 2308 } 2309 } 2310 2311 qemu_co_mutex_lock(&s->lock); 2312 2313 ret = qcow2_handle_l2meta(bs, &l2meta, true); 2314 if (ret) { 2315 goto out_locked; 2316 } 2317 2318 bytes -= cur_bytes; 2319 offset += cur_bytes; 2320 bytes_done += cur_bytes; 2321 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2322 } 2323 ret = 0; 2324 goto out_locked; 2325 2326 out_unlocked: 2327 qemu_co_mutex_lock(&s->lock); 2328 2329 out_locked: 2330 qcow2_handle_l2meta(bs, &l2meta, false); 2331 2332 qemu_co_mutex_unlock(&s->lock); 2333 2334 qemu_iovec_destroy(&hd_qiov); 2335 qemu_vfree(cluster_data); 2336 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2337 2338 return ret; 2339 } 2340 2341 static int qcow2_inactivate(BlockDriverState *bs) 2342 { 2343 BDRVQcow2State *s = bs->opaque; 2344 int ret, result = 0; 2345 Error *local_err = NULL; 2346 2347 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2348 if (local_err != NULL) { 2349 result = -EINVAL; 2350 error_reportf_err(local_err, "Lost persistent bitmaps during " 2351 "inactivation of node '%s': ", 2352 bdrv_get_device_or_node_name(bs)); 2353 } 2354 2355 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2356 if (ret) { 2357 result = ret; 2358 error_report("Failed to flush the L2 table cache: %s", 2359 strerror(-ret)); 2360 } 2361 2362 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2363 if (ret) { 2364 result = ret; 2365 error_report("Failed to flush the refcount block cache: %s", 2366 strerror(-ret)); 2367 } 2368 2369 if (result == 0) { 2370 qcow2_mark_clean(bs); 2371 } 2372 2373 return result; 2374 } 2375 2376 static void qcow2_close(BlockDriverState *bs) 2377 { 2378 BDRVQcow2State *s = bs->opaque; 2379 qemu_vfree(s->l1_table); 2380 /* else pre-write overlap checks in cache_destroy may crash */ 2381 s->l1_table = NULL; 2382 2383 if (!(s->flags & BDRV_O_INACTIVE)) { 2384 qcow2_inactivate(bs); 2385 } 2386 2387 cache_clean_timer_del(bs); 2388 qcow2_cache_destroy(s->l2_table_cache); 2389 qcow2_cache_destroy(s->refcount_block_cache); 2390 2391 qcrypto_block_free(s->crypto); 2392 s->crypto = NULL; 2393 2394 g_free(s->unknown_header_fields); 2395 cleanup_unknown_header_ext(bs); 2396 2397 g_free(s->image_data_file); 2398 g_free(s->image_backing_file); 2399 g_free(s->image_backing_format); 2400 2401 if (has_data_file(bs)) { 2402 bdrv_unref_child(bs, s->data_file); 2403 } 2404 2405 qcow2_refcount_close(bs); 2406 qcow2_free_snapshots(bs); 2407 } 2408 2409 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, 2410 Error **errp) 2411 { 2412 BDRVQcow2State *s = bs->opaque; 2413 int flags = s->flags; 2414 QCryptoBlock *crypto = NULL; 2415 QDict *options; 2416 Error *local_err = NULL; 2417 int ret; 2418 2419 /* 2420 * Backing files are read-only which makes all of their metadata immutable, 2421 * that means we don't have to worry about reopening them here. 2422 */ 2423 2424 crypto = s->crypto; 2425 s->crypto = NULL; 2426 2427 qcow2_close(bs); 2428 2429 memset(s, 0, sizeof(BDRVQcow2State)); 2430 options = qdict_clone_shallow(bs->options); 2431 2432 flags &= ~BDRV_O_INACTIVE; 2433 qemu_co_mutex_lock(&s->lock); 2434 ret = qcow2_do_open(bs, options, flags, &local_err); 2435 qemu_co_mutex_unlock(&s->lock); 2436 qobject_unref(options); 2437 if (local_err) { 2438 error_propagate_prepend(errp, local_err, 2439 "Could not reopen qcow2 layer: "); 2440 bs->drv = NULL; 2441 return; 2442 } else if (ret < 0) { 2443 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2444 bs->drv = NULL; 2445 return; 2446 } 2447 2448 s->crypto = crypto; 2449 } 2450 2451 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2452 size_t len, size_t buflen) 2453 { 2454 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2455 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2456 2457 if (buflen < ext_len) { 2458 return -ENOSPC; 2459 } 2460 2461 *ext_backing_fmt = (QCowExtension) { 2462 .magic = cpu_to_be32(magic), 2463 .len = cpu_to_be32(len), 2464 }; 2465 2466 if (len) { 2467 memcpy(buf + sizeof(QCowExtension), s, len); 2468 } 2469 2470 return ext_len; 2471 } 2472 2473 /* 2474 * Updates the qcow2 header, including the variable length parts of it, i.e. 2475 * the backing file name and all extensions. qcow2 was not designed to allow 2476 * such changes, so if we run out of space (we can only use the first cluster) 2477 * this function may fail. 2478 * 2479 * Returns 0 on success, -errno in error cases. 2480 */ 2481 int qcow2_update_header(BlockDriverState *bs) 2482 { 2483 BDRVQcow2State *s = bs->opaque; 2484 QCowHeader *header; 2485 char *buf; 2486 size_t buflen = s->cluster_size; 2487 int ret; 2488 uint64_t total_size; 2489 uint32_t refcount_table_clusters; 2490 size_t header_length; 2491 Qcow2UnknownHeaderExtension *uext; 2492 2493 buf = qemu_blockalign(bs, buflen); 2494 2495 /* Header structure */ 2496 header = (QCowHeader*) buf; 2497 2498 if (buflen < sizeof(*header)) { 2499 ret = -ENOSPC; 2500 goto fail; 2501 } 2502 2503 header_length = sizeof(*header) + s->unknown_header_fields_size; 2504 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2505 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2506 2507 *header = (QCowHeader) { 2508 /* Version 2 fields */ 2509 .magic = cpu_to_be32(QCOW_MAGIC), 2510 .version = cpu_to_be32(s->qcow_version), 2511 .backing_file_offset = 0, 2512 .backing_file_size = 0, 2513 .cluster_bits = cpu_to_be32(s->cluster_bits), 2514 .size = cpu_to_be64(total_size), 2515 .crypt_method = cpu_to_be32(s->crypt_method_header), 2516 .l1_size = cpu_to_be32(s->l1_size), 2517 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2518 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2519 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2520 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2521 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2522 2523 /* Version 3 fields */ 2524 .incompatible_features = cpu_to_be64(s->incompatible_features), 2525 .compatible_features = cpu_to_be64(s->compatible_features), 2526 .autoclear_features = cpu_to_be64(s->autoclear_features), 2527 .refcount_order = cpu_to_be32(s->refcount_order), 2528 .header_length = cpu_to_be32(header_length), 2529 }; 2530 2531 /* For older versions, write a shorter header */ 2532 switch (s->qcow_version) { 2533 case 2: 2534 ret = offsetof(QCowHeader, incompatible_features); 2535 break; 2536 case 3: 2537 ret = sizeof(*header); 2538 break; 2539 default: 2540 ret = -EINVAL; 2541 goto fail; 2542 } 2543 2544 buf += ret; 2545 buflen -= ret; 2546 memset(buf, 0, buflen); 2547 2548 /* Preserve any unknown field in the header */ 2549 if (s->unknown_header_fields_size) { 2550 if (buflen < s->unknown_header_fields_size) { 2551 ret = -ENOSPC; 2552 goto fail; 2553 } 2554 2555 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2556 buf += s->unknown_header_fields_size; 2557 buflen -= s->unknown_header_fields_size; 2558 } 2559 2560 /* Backing file format header extension */ 2561 if (s->image_backing_format) { 2562 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2563 s->image_backing_format, 2564 strlen(s->image_backing_format), 2565 buflen); 2566 if (ret < 0) { 2567 goto fail; 2568 } 2569 2570 buf += ret; 2571 buflen -= ret; 2572 } 2573 2574 /* External data file header extension */ 2575 if (has_data_file(bs) && s->image_data_file) { 2576 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE, 2577 s->image_data_file, strlen(s->image_data_file), 2578 buflen); 2579 if (ret < 0) { 2580 goto fail; 2581 } 2582 2583 buf += ret; 2584 buflen -= ret; 2585 } 2586 2587 /* Full disk encryption header pointer extension */ 2588 if (s->crypto_header.offset != 0) { 2589 s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset); 2590 s->crypto_header.length = cpu_to_be64(s->crypto_header.length); 2591 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2592 &s->crypto_header, sizeof(s->crypto_header), 2593 buflen); 2594 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 2595 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 2596 if (ret < 0) { 2597 goto fail; 2598 } 2599 buf += ret; 2600 buflen -= ret; 2601 } 2602 2603 /* Feature table */ 2604 if (s->qcow_version >= 3) { 2605 Qcow2Feature features[] = { 2606 { 2607 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2608 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2609 .name = "dirty bit", 2610 }, 2611 { 2612 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2613 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2614 .name = "corrupt bit", 2615 }, 2616 { 2617 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2618 .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR, 2619 .name = "external data file", 2620 }, 2621 { 2622 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2623 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2624 .name = "lazy refcounts", 2625 }, 2626 }; 2627 2628 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2629 features, sizeof(features), buflen); 2630 if (ret < 0) { 2631 goto fail; 2632 } 2633 buf += ret; 2634 buflen -= ret; 2635 } 2636 2637 /* Bitmap extension */ 2638 if (s->nb_bitmaps > 0) { 2639 Qcow2BitmapHeaderExt bitmaps_header = { 2640 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2641 .bitmap_directory_size = 2642 cpu_to_be64(s->bitmap_directory_size), 2643 .bitmap_directory_offset = 2644 cpu_to_be64(s->bitmap_directory_offset) 2645 }; 2646 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2647 &bitmaps_header, sizeof(bitmaps_header), 2648 buflen); 2649 if (ret < 0) { 2650 goto fail; 2651 } 2652 buf += ret; 2653 buflen -= ret; 2654 } 2655 2656 /* Keep unknown header extensions */ 2657 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2658 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2659 if (ret < 0) { 2660 goto fail; 2661 } 2662 2663 buf += ret; 2664 buflen -= ret; 2665 } 2666 2667 /* End of header extensions */ 2668 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2669 if (ret < 0) { 2670 goto fail; 2671 } 2672 2673 buf += ret; 2674 buflen -= ret; 2675 2676 /* Backing file name */ 2677 if (s->image_backing_file) { 2678 size_t backing_file_len = strlen(s->image_backing_file); 2679 2680 if (buflen < backing_file_len) { 2681 ret = -ENOSPC; 2682 goto fail; 2683 } 2684 2685 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2686 strncpy(buf, s->image_backing_file, buflen); 2687 2688 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2689 header->backing_file_size = cpu_to_be32(backing_file_len); 2690 } 2691 2692 /* Write the new header */ 2693 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2694 if (ret < 0) { 2695 goto fail; 2696 } 2697 2698 ret = 0; 2699 fail: 2700 qemu_vfree(header); 2701 return ret; 2702 } 2703 2704 static int qcow2_change_backing_file(BlockDriverState *bs, 2705 const char *backing_file, const char *backing_fmt) 2706 { 2707 BDRVQcow2State *s = bs->opaque; 2708 2709 /* Adding a backing file means that the external data file alone won't be 2710 * enough to make sense of the content */ 2711 if (backing_file && data_file_is_raw(bs)) { 2712 return -EINVAL; 2713 } 2714 2715 if (backing_file && strlen(backing_file) > 1023) { 2716 return -EINVAL; 2717 } 2718 2719 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), 2720 backing_file ?: ""); 2721 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2722 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2723 2724 g_free(s->image_backing_file); 2725 g_free(s->image_backing_format); 2726 2727 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2728 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2729 2730 return qcow2_update_header(bs); 2731 } 2732 2733 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2734 { 2735 if (g_str_equal(encryptfmt, "luks")) { 2736 return QCOW_CRYPT_LUKS; 2737 } else if (g_str_equal(encryptfmt, "aes")) { 2738 return QCOW_CRYPT_AES; 2739 } else { 2740 return -EINVAL; 2741 } 2742 } 2743 2744 static int qcow2_set_up_encryption(BlockDriverState *bs, 2745 QCryptoBlockCreateOptions *cryptoopts, 2746 Error **errp) 2747 { 2748 BDRVQcow2State *s = bs->opaque; 2749 QCryptoBlock *crypto = NULL; 2750 int fmt, ret; 2751 2752 switch (cryptoopts->format) { 2753 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 2754 fmt = QCOW_CRYPT_LUKS; 2755 break; 2756 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 2757 fmt = QCOW_CRYPT_AES; 2758 break; 2759 default: 2760 error_setg(errp, "Crypto format not supported in qcow2"); 2761 return -EINVAL; 2762 } 2763 2764 s->crypt_method_header = fmt; 2765 2766 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2767 qcow2_crypto_hdr_init_func, 2768 qcow2_crypto_hdr_write_func, 2769 bs, errp); 2770 if (!crypto) { 2771 return -EINVAL; 2772 } 2773 2774 ret = qcow2_update_header(bs); 2775 if (ret < 0) { 2776 error_setg_errno(errp, -ret, "Could not write encryption header"); 2777 goto out; 2778 } 2779 2780 ret = 0; 2781 out: 2782 qcrypto_block_free(crypto); 2783 return ret; 2784 } 2785 2786 /** 2787 * Preallocates metadata structures for data clusters between @offset (in the 2788 * guest disk) and @new_length (which is thus generally the new guest disk 2789 * size). 2790 * 2791 * Returns: 0 on success, -errno on failure. 2792 */ 2793 static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, 2794 uint64_t new_length, PreallocMode mode, 2795 Error **errp) 2796 { 2797 BDRVQcow2State *s = bs->opaque; 2798 uint64_t bytes; 2799 uint64_t host_offset = 0; 2800 int64_t file_length; 2801 unsigned int cur_bytes; 2802 int ret; 2803 QCowL2Meta *meta; 2804 2805 assert(offset <= new_length); 2806 bytes = new_length - offset; 2807 2808 while (bytes) { 2809 cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size)); 2810 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2811 &host_offset, &meta); 2812 if (ret < 0) { 2813 error_setg_errno(errp, -ret, "Allocating clusters failed"); 2814 return ret; 2815 } 2816 2817 while (meta) { 2818 QCowL2Meta *next = meta->next; 2819 2820 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2821 if (ret < 0) { 2822 error_setg_errno(errp, -ret, "Mapping clusters failed"); 2823 qcow2_free_any_clusters(bs, meta->alloc_offset, 2824 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2825 return ret; 2826 } 2827 2828 /* There are no dependent requests, but we need to remove our 2829 * request from the list of in-flight requests */ 2830 QLIST_REMOVE(meta, next_in_flight); 2831 2832 g_free(meta); 2833 meta = next; 2834 } 2835 2836 /* TODO Preallocate data if requested */ 2837 2838 bytes -= cur_bytes; 2839 offset += cur_bytes; 2840 } 2841 2842 /* 2843 * It is expected that the image file is large enough to actually contain 2844 * all of the allocated clusters (otherwise we get failing reads after 2845 * EOF). Extend the image to the last allocated sector. 2846 */ 2847 file_length = bdrv_getlength(s->data_file->bs); 2848 if (file_length < 0) { 2849 error_setg_errno(errp, -file_length, "Could not get file size"); 2850 return file_length; 2851 } 2852 2853 if (host_offset + cur_bytes > file_length) { 2854 if (mode == PREALLOC_MODE_METADATA) { 2855 mode = PREALLOC_MODE_OFF; 2856 } 2857 ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, mode, 2858 errp); 2859 if (ret < 0) { 2860 return ret; 2861 } 2862 } 2863 2864 return 0; 2865 } 2866 2867 /* qcow2_refcount_metadata_size: 2868 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2869 * @cluster_size: size of a cluster, in bytes 2870 * @refcount_order: refcount bits power-of-2 exponent 2871 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2872 * needs to be 2873 * 2874 * Returns: Number of bytes required for refcount blocks and table metadata. 2875 */ 2876 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2877 int refcount_order, bool generous_increase, 2878 uint64_t *refblock_count) 2879 { 2880 /* 2881 * Every host cluster is reference-counted, including metadata (even 2882 * refcount metadata is recursively included). 2883 * 2884 * An accurate formula for the size of refcount metadata size is difficult 2885 * to derive. An easier method of calculation is finding the fixed point 2886 * where no further refcount blocks or table clusters are required to 2887 * reference count every cluster. 2888 */ 2889 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2890 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2891 int64_t table = 0; /* number of refcount table clusters */ 2892 int64_t blocks = 0; /* number of refcount block clusters */ 2893 int64_t last; 2894 int64_t n = 0; 2895 2896 do { 2897 last = n; 2898 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2899 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2900 n = clusters + blocks + table; 2901 2902 if (n == last && generous_increase) { 2903 clusters += DIV_ROUND_UP(table, 2); 2904 n = 0; /* force another loop */ 2905 generous_increase = false; 2906 } 2907 } while (n != last); 2908 2909 if (refblock_count) { 2910 *refblock_count = blocks; 2911 } 2912 2913 return (blocks + table) * cluster_size; 2914 } 2915 2916 /** 2917 * qcow2_calc_prealloc_size: 2918 * @total_size: virtual disk size in bytes 2919 * @cluster_size: cluster size in bytes 2920 * @refcount_order: refcount bits power-of-2 exponent 2921 * 2922 * Returns: Total number of bytes required for the fully allocated image 2923 * (including metadata). 2924 */ 2925 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2926 size_t cluster_size, 2927 int refcount_order) 2928 { 2929 int64_t meta_size = 0; 2930 uint64_t nl1e, nl2e; 2931 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); 2932 2933 /* header: 1 cluster */ 2934 meta_size += cluster_size; 2935 2936 /* total size of L2 tables */ 2937 nl2e = aligned_total_size / cluster_size; 2938 nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t)); 2939 meta_size += nl2e * sizeof(uint64_t); 2940 2941 /* total size of L1 tables */ 2942 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2943 nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t)); 2944 meta_size += nl1e * sizeof(uint64_t); 2945 2946 /* total size of refcount table and blocks */ 2947 meta_size += qcow2_refcount_metadata_size( 2948 (meta_size + aligned_total_size) / cluster_size, 2949 cluster_size, refcount_order, false, NULL); 2950 2951 return meta_size + aligned_total_size; 2952 } 2953 2954 static bool validate_cluster_size(size_t cluster_size, Error **errp) 2955 { 2956 int cluster_bits = ctz32(cluster_size); 2957 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2958 (1 << cluster_bits) != cluster_size) 2959 { 2960 error_setg(errp, "Cluster size must be a power of two between %d and " 2961 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2962 return false; 2963 } 2964 return true; 2965 } 2966 2967 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2968 { 2969 size_t cluster_size; 2970 2971 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2972 DEFAULT_CLUSTER_SIZE); 2973 if (!validate_cluster_size(cluster_size, errp)) { 2974 return 0; 2975 } 2976 return cluster_size; 2977 } 2978 2979 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2980 { 2981 char *buf; 2982 int ret; 2983 2984 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2985 if (!buf) { 2986 ret = 3; /* default */ 2987 } else if (!strcmp(buf, "0.10")) { 2988 ret = 2; 2989 } else if (!strcmp(buf, "1.1")) { 2990 ret = 3; 2991 } else { 2992 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2993 ret = -EINVAL; 2994 } 2995 g_free(buf); 2996 return ret; 2997 } 2998 2999 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 3000 Error **errp) 3001 { 3002 uint64_t refcount_bits; 3003 3004 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 3005 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 3006 error_setg(errp, "Refcount width must be a power of two and may not " 3007 "exceed 64 bits"); 3008 return 0; 3009 } 3010 3011 if (version < 3 && refcount_bits != 16) { 3012 error_setg(errp, "Different refcount widths than 16 bits require " 3013 "compatibility level 1.1 or above (use compat=1.1 or " 3014 "greater)"); 3015 return 0; 3016 } 3017 3018 return refcount_bits; 3019 } 3020 3021 static int coroutine_fn 3022 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 3023 { 3024 BlockdevCreateOptionsQcow2 *qcow2_opts; 3025 QDict *options; 3026 3027 /* 3028 * Open the image file and write a minimal qcow2 header. 3029 * 3030 * We keep things simple and start with a zero-sized image. We also 3031 * do without refcount blocks or a L1 table for now. We'll fix the 3032 * inconsistency later. 3033 * 3034 * We do need a refcount table because growing the refcount table means 3035 * allocating two new refcount blocks - the seconds of which would be at 3036 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 3037 * size for any qcow2 image. 3038 */ 3039 BlockBackend *blk = NULL; 3040 BlockDriverState *bs = NULL; 3041 BlockDriverState *data_bs = NULL; 3042 QCowHeader *header; 3043 size_t cluster_size; 3044 int version; 3045 int refcount_order; 3046 uint64_t* refcount_table; 3047 Error *local_err = NULL; 3048 int ret; 3049 3050 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); 3051 qcow2_opts = &create_options->u.qcow2; 3052 3053 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); 3054 if (bs == NULL) { 3055 return -EIO; 3056 } 3057 3058 /* Validate options and set default values */ 3059 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { 3060 error_setg(errp, "Image size must be a multiple of 512 bytes"); 3061 ret = -EINVAL; 3062 goto out; 3063 } 3064 3065 if (qcow2_opts->has_version) { 3066 switch (qcow2_opts->version) { 3067 case BLOCKDEV_QCOW2_VERSION_V2: 3068 version = 2; 3069 break; 3070 case BLOCKDEV_QCOW2_VERSION_V3: 3071 version = 3; 3072 break; 3073 default: 3074 g_assert_not_reached(); 3075 } 3076 } else { 3077 version = 3; 3078 } 3079 3080 if (qcow2_opts->has_cluster_size) { 3081 cluster_size = qcow2_opts->cluster_size; 3082 } else { 3083 cluster_size = DEFAULT_CLUSTER_SIZE; 3084 } 3085 3086 if (!validate_cluster_size(cluster_size, errp)) { 3087 ret = -EINVAL; 3088 goto out; 3089 } 3090 3091 if (!qcow2_opts->has_preallocation) { 3092 qcow2_opts->preallocation = PREALLOC_MODE_OFF; 3093 } 3094 if (qcow2_opts->has_backing_file && 3095 qcow2_opts->preallocation != PREALLOC_MODE_OFF) 3096 { 3097 error_setg(errp, "Backing file and preallocation cannot be used at " 3098 "the same time"); 3099 ret = -EINVAL; 3100 goto out; 3101 } 3102 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { 3103 error_setg(errp, "Backing format cannot be used without backing file"); 3104 ret = -EINVAL; 3105 goto out; 3106 } 3107 3108 if (!qcow2_opts->has_lazy_refcounts) { 3109 qcow2_opts->lazy_refcounts = false; 3110 } 3111 if (version < 3 && qcow2_opts->lazy_refcounts) { 3112 error_setg(errp, "Lazy refcounts only supported with compatibility " 3113 "level 1.1 and above (use version=v3 or greater)"); 3114 ret = -EINVAL; 3115 goto out; 3116 } 3117 3118 if (!qcow2_opts->has_refcount_bits) { 3119 qcow2_opts->refcount_bits = 16; 3120 } 3121 if (qcow2_opts->refcount_bits > 64 || 3122 !is_power_of_2(qcow2_opts->refcount_bits)) 3123 { 3124 error_setg(errp, "Refcount width must be a power of two and may not " 3125 "exceed 64 bits"); 3126 ret = -EINVAL; 3127 goto out; 3128 } 3129 if (version < 3 && qcow2_opts->refcount_bits != 16) { 3130 error_setg(errp, "Different refcount widths than 16 bits require " 3131 "compatibility level 1.1 or above (use version=v3 or " 3132 "greater)"); 3133 ret = -EINVAL; 3134 goto out; 3135 } 3136 refcount_order = ctz32(qcow2_opts->refcount_bits); 3137 3138 if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) { 3139 error_setg(errp, "data-file-raw requires data-file"); 3140 ret = -EINVAL; 3141 goto out; 3142 } 3143 if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) { 3144 error_setg(errp, "Backing file and data-file-raw cannot be used at " 3145 "the same time"); 3146 ret = -EINVAL; 3147 goto out; 3148 } 3149 3150 if (qcow2_opts->data_file) { 3151 if (version < 3) { 3152 error_setg(errp, "External data files are only supported with " 3153 "compatibility level 1.1 and above (use version=v3 or " 3154 "greater)"); 3155 ret = -EINVAL; 3156 goto out; 3157 } 3158 data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp); 3159 if (data_bs == NULL) { 3160 ret = -EIO; 3161 goto out; 3162 } 3163 } 3164 3165 /* Create BlockBackend to write to the image */ 3166 blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 3167 ret = blk_insert_bs(blk, bs, errp); 3168 if (ret < 0) { 3169 goto out; 3170 } 3171 blk_set_allow_write_beyond_eof(blk, true); 3172 3173 /* Clear the protocol layer and preallocate it if necessary */ 3174 ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); 3175 if (ret < 0) { 3176 goto out; 3177 } 3178 3179 /* Write the header */ 3180 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 3181 header = g_malloc0(cluster_size); 3182 *header = (QCowHeader) { 3183 .magic = cpu_to_be32(QCOW_MAGIC), 3184 .version = cpu_to_be32(version), 3185 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 3186 .size = cpu_to_be64(0), 3187 .l1_table_offset = cpu_to_be64(0), 3188 .l1_size = cpu_to_be32(0), 3189 .refcount_table_offset = cpu_to_be64(cluster_size), 3190 .refcount_table_clusters = cpu_to_be32(1), 3191 .refcount_order = cpu_to_be32(refcount_order), 3192 .header_length = cpu_to_be32(sizeof(*header)), 3193 }; 3194 3195 /* We'll update this to correct value later */ 3196 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 3197 3198 if (qcow2_opts->lazy_refcounts) { 3199 header->compatible_features |= 3200 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 3201 } 3202 if (data_bs) { 3203 header->incompatible_features |= 3204 cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE); 3205 } 3206 if (qcow2_opts->data_file_raw) { 3207 header->autoclear_features |= 3208 cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW); 3209 } 3210 3211 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 3212 g_free(header); 3213 if (ret < 0) { 3214 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 3215 goto out; 3216 } 3217 3218 /* Write a refcount table with one refcount block */ 3219 refcount_table = g_malloc0(2 * cluster_size); 3220 refcount_table[0] = cpu_to_be64(2 * cluster_size); 3221 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 3222 g_free(refcount_table); 3223 3224 if (ret < 0) { 3225 error_setg_errno(errp, -ret, "Could not write refcount table"); 3226 goto out; 3227 } 3228 3229 blk_unref(blk); 3230 blk = NULL; 3231 3232 /* 3233 * And now open the image and make it consistent first (i.e. increase the 3234 * refcount of the cluster that is occupied by the header and the refcount 3235 * table) 3236 */ 3237 options = qdict_new(); 3238 qdict_put_str(options, "driver", "qcow2"); 3239 qdict_put_str(options, "file", bs->node_name); 3240 if (data_bs) { 3241 qdict_put_str(options, "data-file", data_bs->node_name); 3242 } 3243 blk = blk_new_open(NULL, NULL, options, 3244 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 3245 &local_err); 3246 if (blk == NULL) { 3247 error_propagate(errp, local_err); 3248 ret = -EIO; 3249 goto out; 3250 } 3251 3252 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 3253 if (ret < 0) { 3254 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 3255 "header and refcount table"); 3256 goto out; 3257 3258 } else if (ret != 0) { 3259 error_report("Huh, first cluster in empty image is already in use?"); 3260 abort(); 3261 } 3262 3263 /* Set the external data file if necessary */ 3264 if (data_bs) { 3265 BDRVQcow2State *s = blk_bs(blk)->opaque; 3266 s->image_data_file = g_strdup(data_bs->filename); 3267 } 3268 3269 /* Create a full header (including things like feature table) */ 3270 ret = qcow2_update_header(blk_bs(blk)); 3271 if (ret < 0) { 3272 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 3273 goto out; 3274 } 3275 3276 /* Okay, now that we have a valid image, let's give it the right size */ 3277 ret = blk_truncate(blk, qcow2_opts->size, qcow2_opts->preallocation, errp); 3278 if (ret < 0) { 3279 error_prepend(errp, "Could not resize image: "); 3280 goto out; 3281 } 3282 3283 /* Want a backing file? There you go.*/ 3284 if (qcow2_opts->has_backing_file) { 3285 const char *backing_format = NULL; 3286 3287 if (qcow2_opts->has_backing_fmt) { 3288 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); 3289 } 3290 3291 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, 3292 backing_format); 3293 if (ret < 0) { 3294 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 3295 "with format '%s'", qcow2_opts->backing_file, 3296 backing_format); 3297 goto out; 3298 } 3299 } 3300 3301 /* Want encryption? There you go. */ 3302 if (qcow2_opts->has_encrypt) { 3303 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); 3304 if (ret < 0) { 3305 goto out; 3306 } 3307 } 3308 3309 blk_unref(blk); 3310 blk = NULL; 3311 3312 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 3313 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 3314 * have to setup decryption context. We're not doing any I/O on the top 3315 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 3316 * not have effect. 3317 */ 3318 options = qdict_new(); 3319 qdict_put_str(options, "driver", "qcow2"); 3320 qdict_put_str(options, "file", bs->node_name); 3321 if (data_bs) { 3322 qdict_put_str(options, "data-file", data_bs->node_name); 3323 } 3324 blk = blk_new_open(NULL, NULL, options, 3325 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 3326 &local_err); 3327 if (blk == NULL) { 3328 error_propagate(errp, local_err); 3329 ret = -EIO; 3330 goto out; 3331 } 3332 3333 ret = 0; 3334 out: 3335 blk_unref(blk); 3336 bdrv_unref(bs); 3337 bdrv_unref(data_bs); 3338 return ret; 3339 } 3340 3341 static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts, 3342 Error **errp) 3343 { 3344 BlockdevCreateOptions *create_options = NULL; 3345 QDict *qdict; 3346 Visitor *v; 3347 BlockDriverState *bs = NULL; 3348 BlockDriverState *data_bs = NULL; 3349 Error *local_err = NULL; 3350 const char *val; 3351 int ret; 3352 3353 /* Only the keyval visitor supports the dotted syntax needed for 3354 * encryption, so go through a QDict before getting a QAPI type. Ignore 3355 * options meant for the protocol layer so that the visitor doesn't 3356 * complain. */ 3357 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, 3358 true); 3359 3360 /* Handle encryption options */ 3361 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 3362 if (val && !strcmp(val, "on")) { 3363 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 3364 } else if (val && !strcmp(val, "off")) { 3365 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 3366 } 3367 3368 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 3369 if (val && !strcmp(val, "aes")) { 3370 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 3371 } 3372 3373 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into 3374 * version=v2/v3 below. */ 3375 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); 3376 if (val && !strcmp(val, "0.10")) { 3377 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); 3378 } else if (val && !strcmp(val, "1.1")) { 3379 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); 3380 } 3381 3382 /* Change legacy command line options into QMP ones */ 3383 static const QDictRenames opt_renames[] = { 3384 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 3385 { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, 3386 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, 3387 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, 3388 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, 3389 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 3390 { BLOCK_OPT_COMPAT_LEVEL, "version" }, 3391 { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" }, 3392 { NULL, NULL }, 3393 }; 3394 3395 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 3396 ret = -EINVAL; 3397 goto finish; 3398 } 3399 3400 /* Create and open the file (protocol layer) */ 3401 ret = bdrv_create_file(filename, opts, errp); 3402 if (ret < 0) { 3403 goto finish; 3404 } 3405 3406 bs = bdrv_open(filename, NULL, NULL, 3407 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 3408 if (bs == NULL) { 3409 ret = -EIO; 3410 goto finish; 3411 } 3412 3413 /* Create and open an external data file (protocol layer) */ 3414 val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE); 3415 if (val) { 3416 ret = bdrv_create_file(val, opts, errp); 3417 if (ret < 0) { 3418 goto finish; 3419 } 3420 3421 data_bs = bdrv_open(val, NULL, NULL, 3422 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 3423 errp); 3424 if (data_bs == NULL) { 3425 ret = -EIO; 3426 goto finish; 3427 } 3428 3429 qdict_del(qdict, BLOCK_OPT_DATA_FILE); 3430 qdict_put_str(qdict, "data-file", data_bs->node_name); 3431 } 3432 3433 /* Set 'driver' and 'node' options */ 3434 qdict_put_str(qdict, "driver", "qcow2"); 3435 qdict_put_str(qdict, "file", bs->node_name); 3436 3437 /* Now get the QAPI type BlockdevCreateOptions */ 3438 v = qobject_input_visitor_new_flat_confused(qdict, errp); 3439 if (!v) { 3440 ret = -EINVAL; 3441 goto finish; 3442 } 3443 3444 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 3445 visit_free(v); 3446 3447 if (local_err) { 3448 error_propagate(errp, local_err); 3449 ret = -EINVAL; 3450 goto finish; 3451 } 3452 3453 /* Silently round up size */ 3454 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, 3455 BDRV_SECTOR_SIZE); 3456 3457 /* Create the qcow2 image (format layer) */ 3458 ret = qcow2_co_create(create_options, errp); 3459 if (ret < 0) { 3460 goto finish; 3461 } 3462 3463 ret = 0; 3464 finish: 3465 qobject_unref(qdict); 3466 bdrv_unref(bs); 3467 bdrv_unref(data_bs); 3468 qapi_free_BlockdevCreateOptions(create_options); 3469 return ret; 3470 } 3471 3472 3473 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3474 { 3475 int64_t nr; 3476 int res; 3477 3478 /* Clamp to image length, before checking status of underlying sectors */ 3479 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3480 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3481 } 3482 3483 if (!bytes) { 3484 return true; 3485 } 3486 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3487 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3488 } 3489 3490 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3491 int64_t offset, int bytes, BdrvRequestFlags flags) 3492 { 3493 int ret; 3494 BDRVQcow2State *s = bs->opaque; 3495 3496 uint32_t head = offset % s->cluster_size; 3497 uint32_t tail = (offset + bytes) % s->cluster_size; 3498 3499 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3500 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3501 tail = 0; 3502 } 3503 3504 if (head || tail) { 3505 uint64_t off; 3506 unsigned int nr; 3507 3508 assert(head + bytes <= s->cluster_size); 3509 3510 /* check whether remainder of cluster already reads as zero */ 3511 if (!(is_zero(bs, offset - head, head) && 3512 is_zero(bs, offset + bytes, 3513 tail ? s->cluster_size - tail : 0))) { 3514 return -ENOTSUP; 3515 } 3516 3517 qemu_co_mutex_lock(&s->lock); 3518 /* We can have new write after previous check */ 3519 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3520 bytes = s->cluster_size; 3521 nr = s->cluster_size; 3522 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3523 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3524 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3525 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3526 qemu_co_mutex_unlock(&s->lock); 3527 return -ENOTSUP; 3528 } 3529 } else { 3530 qemu_co_mutex_lock(&s->lock); 3531 } 3532 3533 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3534 3535 /* Whatever is left can use real zero clusters */ 3536 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3537 qemu_co_mutex_unlock(&s->lock); 3538 3539 return ret; 3540 } 3541 3542 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3543 int64_t offset, int bytes) 3544 { 3545 int ret; 3546 BDRVQcow2State *s = bs->opaque; 3547 3548 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3549 assert(bytes < s->cluster_size); 3550 /* Ignore partial clusters, except for the special case of the 3551 * complete partial cluster at the end of an unaligned file */ 3552 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3553 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3554 return -ENOTSUP; 3555 } 3556 } 3557 3558 qemu_co_mutex_lock(&s->lock); 3559 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3560 false); 3561 qemu_co_mutex_unlock(&s->lock); 3562 return ret; 3563 } 3564 3565 static int coroutine_fn 3566 qcow2_co_copy_range_from(BlockDriverState *bs, 3567 BdrvChild *src, uint64_t src_offset, 3568 BdrvChild *dst, uint64_t dst_offset, 3569 uint64_t bytes, BdrvRequestFlags read_flags, 3570 BdrvRequestFlags write_flags) 3571 { 3572 BDRVQcow2State *s = bs->opaque; 3573 int ret; 3574 unsigned int cur_bytes; /* number of bytes in current iteration */ 3575 BdrvChild *child = NULL; 3576 BdrvRequestFlags cur_write_flags; 3577 3578 assert(!bs->encrypted); 3579 qemu_co_mutex_lock(&s->lock); 3580 3581 while (bytes != 0) { 3582 uint64_t copy_offset = 0; 3583 /* prepare next request */ 3584 cur_bytes = MIN(bytes, INT_MAX); 3585 cur_write_flags = write_flags; 3586 3587 ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, ©_offset); 3588 if (ret < 0) { 3589 goto out; 3590 } 3591 3592 switch (ret) { 3593 case QCOW2_CLUSTER_UNALLOCATED: 3594 if (bs->backing && bs->backing->bs) { 3595 int64_t backing_length = bdrv_getlength(bs->backing->bs); 3596 if (src_offset >= backing_length) { 3597 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3598 } else { 3599 child = bs->backing; 3600 cur_bytes = MIN(cur_bytes, backing_length - src_offset); 3601 copy_offset = src_offset; 3602 } 3603 } else { 3604 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3605 } 3606 break; 3607 3608 case QCOW2_CLUSTER_ZERO_PLAIN: 3609 case QCOW2_CLUSTER_ZERO_ALLOC: 3610 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3611 break; 3612 3613 case QCOW2_CLUSTER_COMPRESSED: 3614 ret = -ENOTSUP; 3615 goto out; 3616 3617 case QCOW2_CLUSTER_NORMAL: 3618 child = s->data_file; 3619 copy_offset += offset_into_cluster(s, src_offset); 3620 if ((copy_offset & 511) != 0) { 3621 ret = -EIO; 3622 goto out; 3623 } 3624 break; 3625 3626 default: 3627 abort(); 3628 } 3629 qemu_co_mutex_unlock(&s->lock); 3630 ret = bdrv_co_copy_range_from(child, 3631 copy_offset, 3632 dst, dst_offset, 3633 cur_bytes, read_flags, cur_write_flags); 3634 qemu_co_mutex_lock(&s->lock); 3635 if (ret < 0) { 3636 goto out; 3637 } 3638 3639 bytes -= cur_bytes; 3640 src_offset += cur_bytes; 3641 dst_offset += cur_bytes; 3642 } 3643 ret = 0; 3644 3645 out: 3646 qemu_co_mutex_unlock(&s->lock); 3647 return ret; 3648 } 3649 3650 static int coroutine_fn 3651 qcow2_co_copy_range_to(BlockDriverState *bs, 3652 BdrvChild *src, uint64_t src_offset, 3653 BdrvChild *dst, uint64_t dst_offset, 3654 uint64_t bytes, BdrvRequestFlags read_flags, 3655 BdrvRequestFlags write_flags) 3656 { 3657 BDRVQcow2State *s = bs->opaque; 3658 int offset_in_cluster; 3659 int ret; 3660 unsigned int cur_bytes; /* number of sectors in current iteration */ 3661 uint64_t cluster_offset; 3662 QCowL2Meta *l2meta = NULL; 3663 3664 assert(!bs->encrypted); 3665 3666 qemu_co_mutex_lock(&s->lock); 3667 3668 while (bytes != 0) { 3669 3670 l2meta = NULL; 3671 3672 offset_in_cluster = offset_into_cluster(s, dst_offset); 3673 cur_bytes = MIN(bytes, INT_MAX); 3674 3675 /* TODO: 3676 * If src->bs == dst->bs, we could simply copy by incrementing 3677 * the refcnt, without copying user data. 3678 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ 3679 ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes, 3680 &cluster_offset, &l2meta); 3681 if (ret < 0) { 3682 goto fail; 3683 } 3684 3685 assert((cluster_offset & 511) == 0); 3686 3687 ret = qcow2_pre_write_overlap_check(bs, 0, 3688 cluster_offset + offset_in_cluster, cur_bytes, true); 3689 if (ret < 0) { 3690 goto fail; 3691 } 3692 3693 qemu_co_mutex_unlock(&s->lock); 3694 ret = bdrv_co_copy_range_to(src, src_offset, 3695 s->data_file, 3696 cluster_offset + offset_in_cluster, 3697 cur_bytes, read_flags, write_flags); 3698 qemu_co_mutex_lock(&s->lock); 3699 if (ret < 0) { 3700 goto fail; 3701 } 3702 3703 ret = qcow2_handle_l2meta(bs, &l2meta, true); 3704 if (ret) { 3705 goto fail; 3706 } 3707 3708 bytes -= cur_bytes; 3709 src_offset += cur_bytes; 3710 dst_offset += cur_bytes; 3711 } 3712 ret = 0; 3713 3714 fail: 3715 qcow2_handle_l2meta(bs, &l2meta, false); 3716 3717 qemu_co_mutex_unlock(&s->lock); 3718 3719 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 3720 3721 return ret; 3722 } 3723 3724 static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, 3725 PreallocMode prealloc, Error **errp) 3726 { 3727 BDRVQcow2State *s = bs->opaque; 3728 uint64_t old_length; 3729 int64_t new_l1_size; 3730 int ret; 3731 QDict *options; 3732 3733 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3734 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3735 { 3736 error_setg(errp, "Unsupported preallocation mode '%s'", 3737 PreallocMode_str(prealloc)); 3738 return -ENOTSUP; 3739 } 3740 3741 if (offset & 511) { 3742 error_setg(errp, "The new size must be a multiple of 512"); 3743 return -EINVAL; 3744 } 3745 3746 qemu_co_mutex_lock(&s->lock); 3747 3748 /* cannot proceed if image has snapshots */ 3749 if (s->nb_snapshots) { 3750 error_setg(errp, "Can't resize an image which has snapshots"); 3751 ret = -ENOTSUP; 3752 goto fail; 3753 } 3754 3755 /* cannot proceed if image has bitmaps */ 3756 if (qcow2_truncate_bitmaps_check(bs, errp)) { 3757 ret = -ENOTSUP; 3758 goto fail; 3759 } 3760 3761 old_length = bs->total_sectors * BDRV_SECTOR_SIZE; 3762 new_l1_size = size_to_l1(s, offset); 3763 3764 if (offset < old_length) { 3765 int64_t last_cluster, old_file_size; 3766 if (prealloc != PREALLOC_MODE_OFF) { 3767 error_setg(errp, 3768 "Preallocation can't be used for shrinking an image"); 3769 ret = -EINVAL; 3770 goto fail; 3771 } 3772 3773 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3774 old_length - ROUND_UP(offset, 3775 s->cluster_size), 3776 QCOW2_DISCARD_ALWAYS, true); 3777 if (ret < 0) { 3778 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3779 goto fail; 3780 } 3781 3782 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3783 if (ret < 0) { 3784 error_setg_errno(errp, -ret, 3785 "Failed to reduce the number of L2 tables"); 3786 goto fail; 3787 } 3788 3789 ret = qcow2_shrink_reftable(bs); 3790 if (ret < 0) { 3791 error_setg_errno(errp, -ret, 3792 "Failed to discard unused refblocks"); 3793 goto fail; 3794 } 3795 3796 old_file_size = bdrv_getlength(bs->file->bs); 3797 if (old_file_size < 0) { 3798 error_setg_errno(errp, -old_file_size, 3799 "Failed to inquire current file length"); 3800 ret = old_file_size; 3801 goto fail; 3802 } 3803 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3804 if (last_cluster < 0) { 3805 error_setg_errno(errp, -last_cluster, 3806 "Failed to find the last cluster"); 3807 ret = last_cluster; 3808 goto fail; 3809 } 3810 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3811 Error *local_err = NULL; 3812 3813 bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3814 PREALLOC_MODE_OFF, &local_err); 3815 if (local_err) { 3816 warn_reportf_err(local_err, 3817 "Failed to truncate the tail of the image: "); 3818 } 3819 } 3820 } else { 3821 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3822 if (ret < 0) { 3823 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3824 goto fail; 3825 } 3826 } 3827 3828 switch (prealloc) { 3829 case PREALLOC_MODE_OFF: 3830 if (has_data_file(bs)) { 3831 ret = bdrv_co_truncate(s->data_file, offset, prealloc, errp); 3832 if (ret < 0) { 3833 goto fail; 3834 } 3835 } 3836 break; 3837 3838 case PREALLOC_MODE_METADATA: 3839 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 3840 if (ret < 0) { 3841 goto fail; 3842 } 3843 break; 3844 3845 case PREALLOC_MODE_FALLOC: 3846 case PREALLOC_MODE_FULL: 3847 { 3848 int64_t allocation_start, host_offset, guest_offset; 3849 int64_t clusters_allocated; 3850 int64_t old_file_size, new_file_size; 3851 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3852 3853 /* With a data file, preallocation means just allocating the metadata 3854 * and forwarding the truncate request to the data file */ 3855 if (has_data_file(bs)) { 3856 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 3857 if (ret < 0) { 3858 goto fail; 3859 } 3860 break; 3861 } 3862 3863 old_file_size = bdrv_getlength(bs->file->bs); 3864 if (old_file_size < 0) { 3865 error_setg_errno(errp, -old_file_size, 3866 "Failed to inquire current file length"); 3867 ret = old_file_size; 3868 goto fail; 3869 } 3870 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3871 3872 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3873 s->cluster_size); 3874 3875 /* This is an overestimation; we will not actually allocate space for 3876 * these in the file but just make sure the new refcount structures are 3877 * able to cover them so we will not have to allocate new refblocks 3878 * while entering the data blocks in the potentially new L2 tables. 3879 * (We do not actually care where the L2 tables are placed. Maybe they 3880 * are already allocated or they can be placed somewhere before 3881 * @old_file_size. It does not matter because they will be fully 3882 * allocated automatically, so they do not need to be covered by the 3883 * preallocation. All that matters is that we will not have to allocate 3884 * new refcount structures for them.) */ 3885 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3886 s->cluster_size / sizeof(uint64_t)); 3887 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3888 * table for a potential head/tail */ 3889 nb_new_l2_tables++; 3890 3891 allocation_start = qcow2_refcount_area(bs, old_file_size, 3892 nb_new_data_clusters + 3893 nb_new_l2_tables, 3894 true, 0, 0); 3895 if (allocation_start < 0) { 3896 error_setg_errno(errp, -allocation_start, 3897 "Failed to resize refcount structures"); 3898 ret = allocation_start; 3899 goto fail; 3900 } 3901 3902 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3903 nb_new_data_clusters); 3904 if (clusters_allocated < 0) { 3905 error_setg_errno(errp, -clusters_allocated, 3906 "Failed to allocate data clusters"); 3907 ret = clusters_allocated; 3908 goto fail; 3909 } 3910 3911 assert(clusters_allocated == nb_new_data_clusters); 3912 3913 /* Allocate the data area */ 3914 new_file_size = allocation_start + 3915 nb_new_data_clusters * s->cluster_size; 3916 ret = bdrv_co_truncate(bs->file, new_file_size, prealloc, errp); 3917 if (ret < 0) { 3918 error_prepend(errp, "Failed to resize underlying file: "); 3919 qcow2_free_clusters(bs, allocation_start, 3920 nb_new_data_clusters * s->cluster_size, 3921 QCOW2_DISCARD_OTHER); 3922 goto fail; 3923 } 3924 3925 /* Create the necessary L2 entries */ 3926 host_offset = allocation_start; 3927 guest_offset = old_length; 3928 while (nb_new_data_clusters) { 3929 int64_t nb_clusters = MIN( 3930 nb_new_data_clusters, 3931 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3932 QCowL2Meta allocation = { 3933 .offset = guest_offset, 3934 .alloc_offset = host_offset, 3935 .nb_clusters = nb_clusters, 3936 }; 3937 qemu_co_queue_init(&allocation.dependent_requests); 3938 3939 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3940 if (ret < 0) { 3941 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3942 qcow2_free_clusters(bs, host_offset, 3943 nb_new_data_clusters * s->cluster_size, 3944 QCOW2_DISCARD_OTHER); 3945 goto fail; 3946 } 3947 3948 guest_offset += nb_clusters * s->cluster_size; 3949 host_offset += nb_clusters * s->cluster_size; 3950 nb_new_data_clusters -= nb_clusters; 3951 } 3952 break; 3953 } 3954 3955 default: 3956 g_assert_not_reached(); 3957 } 3958 3959 if (prealloc != PREALLOC_MODE_OFF) { 3960 /* Flush metadata before actually changing the image size */ 3961 ret = qcow2_write_caches(bs); 3962 if (ret < 0) { 3963 error_setg_errno(errp, -ret, 3964 "Failed to flush the preallocated area to disk"); 3965 goto fail; 3966 } 3967 } 3968 3969 bs->total_sectors = offset / BDRV_SECTOR_SIZE; 3970 3971 /* write updated header.size */ 3972 offset = cpu_to_be64(offset); 3973 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3974 &offset, sizeof(uint64_t)); 3975 if (ret < 0) { 3976 error_setg_errno(errp, -ret, "Failed to update the image size"); 3977 goto fail; 3978 } 3979 3980 s->l1_vm_state_index = new_l1_size; 3981 3982 /* Update cache sizes */ 3983 options = qdict_clone_shallow(bs->options); 3984 ret = qcow2_update_options(bs, options, s->flags, errp); 3985 qobject_unref(options); 3986 if (ret < 0) { 3987 goto fail; 3988 } 3989 ret = 0; 3990 fail: 3991 qemu_co_mutex_unlock(&s->lock); 3992 return ret; 3993 } 3994 3995 /* XXX: put compressed sectors first, then all the cluster aligned 3996 tables to avoid losing bytes in alignment */ 3997 static coroutine_fn int 3998 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 3999 uint64_t bytes, QEMUIOVector *qiov) 4000 { 4001 BDRVQcow2State *s = bs->opaque; 4002 int ret; 4003 ssize_t out_len; 4004 uint8_t *buf, *out_buf; 4005 uint64_t cluster_offset; 4006 4007 if (has_data_file(bs)) { 4008 return -ENOTSUP; 4009 } 4010 4011 if (bytes == 0) { 4012 /* align end of file to a sector boundary to ease reading with 4013 sector based I/Os */ 4014 int64_t len = bdrv_getlength(bs->file->bs); 4015 if (len < 0) { 4016 return len; 4017 } 4018 return bdrv_co_truncate(bs->file, len, PREALLOC_MODE_OFF, NULL); 4019 } 4020 4021 if (offset_into_cluster(s, offset)) { 4022 return -EINVAL; 4023 } 4024 4025 buf = qemu_blockalign(bs, s->cluster_size); 4026 if (bytes != s->cluster_size) { 4027 if (bytes > s->cluster_size || 4028 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 4029 { 4030 qemu_vfree(buf); 4031 return -EINVAL; 4032 } 4033 /* Zero-pad last write if image size is not cluster aligned */ 4034 memset(buf + bytes, 0, s->cluster_size - bytes); 4035 } 4036 qemu_iovec_to_buf(qiov, 0, buf, bytes); 4037 4038 out_buf = g_malloc(s->cluster_size); 4039 4040 out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1, 4041 buf, s->cluster_size); 4042 if (out_len == -ENOMEM) { 4043 /* could not compress: write normal cluster */ 4044 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 4045 if (ret < 0) { 4046 goto fail; 4047 } 4048 goto success; 4049 } else if (out_len < 0) { 4050 ret = -EINVAL; 4051 goto fail; 4052 } 4053 4054 qemu_co_mutex_lock(&s->lock); 4055 ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len, 4056 &cluster_offset); 4057 if (ret < 0) { 4058 qemu_co_mutex_unlock(&s->lock); 4059 goto fail; 4060 } 4061 4062 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true); 4063 qemu_co_mutex_unlock(&s->lock); 4064 if (ret < 0) { 4065 goto fail; 4066 } 4067 4068 BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED); 4069 ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0); 4070 if (ret < 0) { 4071 goto fail; 4072 } 4073 success: 4074 ret = 0; 4075 fail: 4076 qemu_vfree(buf); 4077 g_free(out_buf); 4078 return ret; 4079 } 4080 4081 static int coroutine_fn 4082 qcow2_co_preadv_compressed(BlockDriverState *bs, 4083 uint64_t file_cluster_offset, 4084 uint64_t offset, 4085 uint64_t bytes, 4086 QEMUIOVector *qiov) 4087 { 4088 BDRVQcow2State *s = bs->opaque; 4089 int ret = 0, csize, nb_csectors; 4090 uint64_t coffset; 4091 uint8_t *buf, *out_buf; 4092 int offset_in_cluster = offset_into_cluster(s, offset); 4093 4094 coffset = file_cluster_offset & s->cluster_offset_mask; 4095 nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1; 4096 csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - 4097 (coffset & ~QCOW2_COMPRESSED_SECTOR_MASK); 4098 4099 buf = g_try_malloc(csize); 4100 if (!buf) { 4101 return -ENOMEM; 4102 } 4103 4104 out_buf = qemu_blockalign(bs, s->cluster_size); 4105 4106 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 4107 ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0); 4108 if (ret < 0) { 4109 goto fail; 4110 } 4111 4112 if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) { 4113 ret = -EIO; 4114 goto fail; 4115 } 4116 4117 qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes); 4118 4119 fail: 4120 qemu_vfree(out_buf); 4121 g_free(buf); 4122 4123 return ret; 4124 } 4125 4126 static int make_completely_empty(BlockDriverState *bs) 4127 { 4128 BDRVQcow2State *s = bs->opaque; 4129 Error *local_err = NULL; 4130 int ret, l1_clusters; 4131 int64_t offset; 4132 uint64_t *new_reftable = NULL; 4133 uint64_t rt_entry, l1_size2; 4134 struct { 4135 uint64_t l1_offset; 4136 uint64_t reftable_offset; 4137 uint32_t reftable_clusters; 4138 } QEMU_PACKED l1_ofs_rt_ofs_cls; 4139 4140 ret = qcow2_cache_empty(bs, s->l2_table_cache); 4141 if (ret < 0) { 4142 goto fail; 4143 } 4144 4145 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 4146 if (ret < 0) { 4147 goto fail; 4148 } 4149 4150 /* Refcounts will be broken utterly */ 4151 ret = qcow2_mark_dirty(bs); 4152 if (ret < 0) { 4153 goto fail; 4154 } 4155 4156 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4157 4158 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4159 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 4160 4161 /* After this call, neither the in-memory nor the on-disk refcount 4162 * information accurately describe the actual references */ 4163 4164 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 4165 l1_clusters * s->cluster_size, 0); 4166 if (ret < 0) { 4167 goto fail_broken_refcounts; 4168 } 4169 memset(s->l1_table, 0, l1_size2); 4170 4171 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 4172 4173 /* Overwrite enough clusters at the beginning of the sectors to place 4174 * the refcount table, a refcount block and the L1 table in; this may 4175 * overwrite parts of the existing refcount and L1 table, which is not 4176 * an issue because the dirty flag is set, complete data loss is in fact 4177 * desired and partial data loss is consequently fine as well */ 4178 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 4179 (2 + l1_clusters) * s->cluster_size, 0); 4180 /* This call (even if it failed overall) may have overwritten on-disk 4181 * refcount structures; in that case, the in-memory refcount information 4182 * will probably differ from the on-disk information which makes the BDS 4183 * unusable */ 4184 if (ret < 0) { 4185 goto fail_broken_refcounts; 4186 } 4187 4188 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4189 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 4190 4191 /* "Create" an empty reftable (one cluster) directly after the image 4192 * header and an empty L1 table three clusters after the image header; 4193 * the cluster between those two will be used as the first refblock */ 4194 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 4195 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 4196 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 4197 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 4198 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 4199 if (ret < 0) { 4200 goto fail_broken_refcounts; 4201 } 4202 4203 s->l1_table_offset = 3 * s->cluster_size; 4204 4205 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 4206 if (!new_reftable) { 4207 ret = -ENOMEM; 4208 goto fail_broken_refcounts; 4209 } 4210 4211 s->refcount_table_offset = s->cluster_size; 4212 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 4213 s->max_refcount_table_index = 0; 4214 4215 g_free(s->refcount_table); 4216 s->refcount_table = new_reftable; 4217 new_reftable = NULL; 4218 4219 /* Now the in-memory refcount information again corresponds to the on-disk 4220 * information (reftable is empty and no refblocks (the refblock cache is 4221 * empty)); however, this means some clusters (e.g. the image header) are 4222 * referenced, but not refcounted, but the normal qcow2 code assumes that 4223 * the in-memory information is always correct */ 4224 4225 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 4226 4227 /* Enter the first refblock into the reftable */ 4228 rt_entry = cpu_to_be64(2 * s->cluster_size); 4229 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 4230 &rt_entry, sizeof(rt_entry)); 4231 if (ret < 0) { 4232 goto fail_broken_refcounts; 4233 } 4234 s->refcount_table[0] = 2 * s->cluster_size; 4235 4236 s->free_cluster_index = 0; 4237 assert(3 + l1_clusters <= s->refcount_block_size); 4238 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 4239 if (offset < 0) { 4240 ret = offset; 4241 goto fail_broken_refcounts; 4242 } else if (offset > 0) { 4243 error_report("First cluster in emptied image is in use"); 4244 abort(); 4245 } 4246 4247 /* Now finally the in-memory information corresponds to the on-disk 4248 * structures and is correct */ 4249 ret = qcow2_mark_clean(bs); 4250 if (ret < 0) { 4251 goto fail; 4252 } 4253 4254 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 4255 PREALLOC_MODE_OFF, &local_err); 4256 if (ret < 0) { 4257 error_report_err(local_err); 4258 goto fail; 4259 } 4260 4261 return 0; 4262 4263 fail_broken_refcounts: 4264 /* The BDS is unusable at this point. If we wanted to make it usable, we 4265 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 4266 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 4267 * again. However, because the functions which could have caused this error 4268 * path to be taken are used by those functions as well, it's very likely 4269 * that that sequence will fail as well. Therefore, just eject the BDS. */ 4270 bs->drv = NULL; 4271 4272 fail: 4273 g_free(new_reftable); 4274 return ret; 4275 } 4276 4277 static int qcow2_make_empty(BlockDriverState *bs) 4278 { 4279 BDRVQcow2State *s = bs->opaque; 4280 uint64_t offset, end_offset; 4281 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 4282 int l1_clusters, ret = 0; 4283 4284 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4285 4286 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 4287 3 + l1_clusters <= s->refcount_block_size && 4288 s->crypt_method_header != QCOW_CRYPT_LUKS && 4289 !has_data_file(bs)) { 4290 /* The following function only works for qcow2 v3 images (it 4291 * requires the dirty flag) and only as long as there are no 4292 * features that reserve extra clusters (such as snapshots, 4293 * LUKS header, or persistent bitmaps), because it completely 4294 * empties the image. Furthermore, the L1 table and three 4295 * additional clusters (image header, refcount table, one 4296 * refcount block) have to fit inside one refcount block. It 4297 * only resets the image file, i.e. does not work with an 4298 * external data file. */ 4299 return make_completely_empty(bs); 4300 } 4301 4302 /* This fallback code simply discards every active cluster; this is slow, 4303 * but works in all cases */ 4304 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 4305 for (offset = 0; offset < end_offset; offset += step) { 4306 /* As this function is generally used after committing an external 4307 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 4308 * default action for this kind of discard is to pass the discard, 4309 * which will ideally result in an actually smaller image file, as 4310 * is probably desired. */ 4311 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 4312 QCOW2_DISCARD_SNAPSHOT, true); 4313 if (ret < 0) { 4314 break; 4315 } 4316 } 4317 4318 return ret; 4319 } 4320 4321 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 4322 { 4323 BDRVQcow2State *s = bs->opaque; 4324 int ret; 4325 4326 qemu_co_mutex_lock(&s->lock); 4327 ret = qcow2_write_caches(bs); 4328 qemu_co_mutex_unlock(&s->lock); 4329 4330 return ret; 4331 } 4332 4333 static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block, 4334 size_t headerlen, void *opaque, Error **errp) 4335 { 4336 size_t *headerlenp = opaque; 4337 4338 /* Stash away the payload size */ 4339 *headerlenp = headerlen; 4340 return 0; 4341 } 4342 4343 static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block, 4344 size_t offset, const uint8_t *buf, size_t buflen, 4345 void *opaque, Error **errp) 4346 { 4347 /* Discard the bytes, we're not actually writing to an image */ 4348 return buflen; 4349 } 4350 4351 /* Determine the number of bytes for the LUKS payload */ 4352 static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len, 4353 Error **errp) 4354 { 4355 QDict *opts_qdict; 4356 QDict *cryptoopts_qdict; 4357 QCryptoBlockCreateOptions *cryptoopts; 4358 QCryptoBlock *crypto; 4359 4360 /* Extract "encrypt." options into a qdict */ 4361 opts_qdict = qemu_opts_to_qdict(opts, NULL); 4362 qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt."); 4363 qobject_unref(opts_qdict); 4364 4365 /* Build QCryptoBlockCreateOptions object from qdict */ 4366 qdict_put_str(cryptoopts_qdict, "format", "luks"); 4367 cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp); 4368 qobject_unref(cryptoopts_qdict); 4369 if (!cryptoopts) { 4370 return false; 4371 } 4372 4373 /* Fake LUKS creation in order to determine the payload size */ 4374 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 4375 qcow2_measure_crypto_hdr_init_func, 4376 qcow2_measure_crypto_hdr_write_func, 4377 len, errp); 4378 qapi_free_QCryptoBlockCreateOptions(cryptoopts); 4379 if (!crypto) { 4380 return false; 4381 } 4382 4383 qcrypto_block_free(crypto); 4384 return true; 4385 } 4386 4387 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 4388 Error **errp) 4389 { 4390 Error *local_err = NULL; 4391 BlockMeasureInfo *info; 4392 uint64_t required = 0; /* bytes that contribute to required size */ 4393 uint64_t virtual_size; /* disk size as seen by guest */ 4394 uint64_t refcount_bits; 4395 uint64_t l2_tables; 4396 uint64_t luks_payload_size = 0; 4397 size_t cluster_size; 4398 int version; 4399 char *optstr; 4400 PreallocMode prealloc; 4401 bool has_backing_file; 4402 bool has_luks; 4403 4404 /* Parse image creation options */ 4405 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 4406 if (local_err) { 4407 goto err; 4408 } 4409 4410 version = qcow2_opt_get_version_del(opts, &local_err); 4411 if (local_err) { 4412 goto err; 4413 } 4414 4415 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 4416 if (local_err) { 4417 goto err; 4418 } 4419 4420 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 4421 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 4422 PREALLOC_MODE_OFF, &local_err); 4423 g_free(optstr); 4424 if (local_err) { 4425 goto err; 4426 } 4427 4428 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 4429 has_backing_file = !!optstr; 4430 g_free(optstr); 4431 4432 optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 4433 has_luks = optstr && strcmp(optstr, "luks") == 0; 4434 g_free(optstr); 4435 4436 if (has_luks) { 4437 size_t headerlen; 4438 4439 if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) { 4440 goto err; 4441 } 4442 4443 luks_payload_size = ROUND_UP(headerlen, cluster_size); 4444 } 4445 4446 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 4447 virtual_size = ROUND_UP(virtual_size, cluster_size); 4448 4449 /* Check that virtual disk size is valid */ 4450 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 4451 cluster_size / sizeof(uint64_t)); 4452 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 4453 error_setg(&local_err, "The image size is too large " 4454 "(try using a larger cluster size)"); 4455 goto err; 4456 } 4457 4458 /* Account for input image */ 4459 if (in_bs) { 4460 int64_t ssize = bdrv_getlength(in_bs); 4461 if (ssize < 0) { 4462 error_setg_errno(&local_err, -ssize, 4463 "Unable to get image virtual_size"); 4464 goto err; 4465 } 4466 4467 virtual_size = ROUND_UP(ssize, cluster_size); 4468 4469 if (has_backing_file) { 4470 /* We don't how much of the backing chain is shared by the input 4471 * image and the new image file. In the worst case the new image's 4472 * backing file has nothing in common with the input image. Be 4473 * conservative and assume all clusters need to be written. 4474 */ 4475 required = virtual_size; 4476 } else { 4477 int64_t offset; 4478 int64_t pnum = 0; 4479 4480 for (offset = 0; offset < ssize; offset += pnum) { 4481 int ret; 4482 4483 ret = bdrv_block_status_above(in_bs, NULL, offset, 4484 ssize - offset, &pnum, NULL, 4485 NULL); 4486 if (ret < 0) { 4487 error_setg_errno(&local_err, -ret, 4488 "Unable to get block status"); 4489 goto err; 4490 } 4491 4492 if (ret & BDRV_BLOCK_ZERO) { 4493 /* Skip zero regions (safe with no backing file) */ 4494 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 4495 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 4496 /* Extend pnum to end of cluster for next iteration */ 4497 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 4498 4499 /* Count clusters we've seen */ 4500 required += offset % cluster_size + pnum; 4501 } 4502 } 4503 } 4504 } 4505 4506 /* Take into account preallocation. Nothing special is needed for 4507 * PREALLOC_MODE_METADATA since metadata is always counted. 4508 */ 4509 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 4510 required = virtual_size; 4511 } 4512 4513 info = g_new(BlockMeasureInfo, 1); 4514 info->fully_allocated = 4515 qcow2_calc_prealloc_size(virtual_size, cluster_size, 4516 ctz32(refcount_bits)) + luks_payload_size; 4517 4518 /* Remove data clusters that are not required. This overestimates the 4519 * required size because metadata needed for the fully allocated file is 4520 * still counted. 4521 */ 4522 info->required = info->fully_allocated - virtual_size + required; 4523 return info; 4524 4525 err: 4526 error_propagate(errp, local_err); 4527 return NULL; 4528 } 4529 4530 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4531 { 4532 BDRVQcow2State *s = bs->opaque; 4533 bdi->unallocated_blocks_are_zero = true; 4534 bdi->cluster_size = s->cluster_size; 4535 bdi->vm_state_offset = qcow2_vm_state_offset(s); 4536 return 0; 4537 } 4538 4539 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, 4540 Error **errp) 4541 { 4542 BDRVQcow2State *s = bs->opaque; 4543 ImageInfoSpecific *spec_info; 4544 QCryptoBlockInfo *encrypt_info = NULL; 4545 Error *local_err = NULL; 4546 4547 if (s->crypto != NULL) { 4548 encrypt_info = qcrypto_block_get_info(s->crypto, &local_err); 4549 if (local_err) { 4550 error_propagate(errp, local_err); 4551 return NULL; 4552 } 4553 } 4554 4555 spec_info = g_new(ImageInfoSpecific, 1); 4556 *spec_info = (ImageInfoSpecific){ 4557 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 4558 .u.qcow2.data = g_new0(ImageInfoSpecificQCow2, 1), 4559 }; 4560 if (s->qcow_version == 2) { 4561 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4562 .compat = g_strdup("0.10"), 4563 .refcount_bits = s->refcount_bits, 4564 }; 4565 } else if (s->qcow_version == 3) { 4566 Qcow2BitmapInfoList *bitmaps; 4567 bitmaps = qcow2_get_bitmap_info_list(bs, &local_err); 4568 if (local_err) { 4569 error_propagate(errp, local_err); 4570 qapi_free_ImageInfoSpecific(spec_info); 4571 return NULL; 4572 } 4573 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4574 .compat = g_strdup("1.1"), 4575 .lazy_refcounts = s->compatible_features & 4576 QCOW2_COMPAT_LAZY_REFCOUNTS, 4577 .has_lazy_refcounts = true, 4578 .corrupt = s->incompatible_features & 4579 QCOW2_INCOMPAT_CORRUPT, 4580 .has_corrupt = true, 4581 .refcount_bits = s->refcount_bits, 4582 .has_bitmaps = !!bitmaps, 4583 .bitmaps = bitmaps, 4584 .has_data_file = !!s->image_data_file, 4585 .data_file = g_strdup(s->image_data_file), 4586 .has_data_file_raw = has_data_file(bs), 4587 .data_file_raw = data_file_is_raw(bs), 4588 }; 4589 } else { 4590 /* if this assertion fails, this probably means a new version was 4591 * added without having it covered here */ 4592 assert(false); 4593 } 4594 4595 if (encrypt_info) { 4596 ImageInfoSpecificQCow2Encryption *qencrypt = 4597 g_new(ImageInfoSpecificQCow2Encryption, 1); 4598 switch (encrypt_info->format) { 4599 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 4600 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 4601 break; 4602 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 4603 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 4604 qencrypt->u.luks = encrypt_info->u.luks; 4605 break; 4606 default: 4607 abort(); 4608 } 4609 /* Since we did shallow copy above, erase any pointers 4610 * in the original info */ 4611 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 4612 qapi_free_QCryptoBlockInfo(encrypt_info); 4613 4614 spec_info->u.qcow2.data->has_encrypt = true; 4615 spec_info->u.qcow2.data->encrypt = qencrypt; 4616 } 4617 4618 return spec_info; 4619 } 4620 4621 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4622 int64_t pos) 4623 { 4624 BDRVQcow2State *s = bs->opaque; 4625 4626 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 4627 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 4628 qiov->size, qiov, 0); 4629 } 4630 4631 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4632 int64_t pos) 4633 { 4634 BDRVQcow2State *s = bs->opaque; 4635 4636 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 4637 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 4638 qiov->size, qiov, 0); 4639 } 4640 4641 /* 4642 * Downgrades an image's version. To achieve this, any incompatible features 4643 * have to be removed. 4644 */ 4645 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 4646 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 4647 Error **errp) 4648 { 4649 BDRVQcow2State *s = bs->opaque; 4650 int current_version = s->qcow_version; 4651 int ret; 4652 4653 /* This is qcow2_downgrade(), not qcow2_upgrade() */ 4654 assert(target_version < current_version); 4655 4656 /* There are no other versions (now) that you can downgrade to */ 4657 assert(target_version == 2); 4658 4659 if (s->refcount_order != 4) { 4660 error_setg(errp, "compat=0.10 requires refcount_bits=16"); 4661 return -ENOTSUP; 4662 } 4663 4664 if (has_data_file(bs)) { 4665 error_setg(errp, "Cannot downgrade an image with a data file"); 4666 return -ENOTSUP; 4667 } 4668 4669 /* clear incompatible features */ 4670 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 4671 ret = qcow2_mark_clean(bs); 4672 if (ret < 0) { 4673 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4674 return ret; 4675 } 4676 } 4677 4678 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 4679 * the first place; if that happens nonetheless, returning -ENOTSUP is the 4680 * best thing to do anyway */ 4681 4682 if (s->incompatible_features) { 4683 error_setg(errp, "Cannot downgrade an image with incompatible features " 4684 "%#" PRIx64 " set", s->incompatible_features); 4685 return -ENOTSUP; 4686 } 4687 4688 /* since we can ignore compatible features, we can set them to 0 as well */ 4689 s->compatible_features = 0; 4690 /* if lazy refcounts have been used, they have already been fixed through 4691 * clearing the dirty flag */ 4692 4693 /* clearing autoclear features is trivial */ 4694 s->autoclear_features = 0; 4695 4696 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 4697 if (ret < 0) { 4698 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); 4699 return ret; 4700 } 4701 4702 s->qcow_version = target_version; 4703 ret = qcow2_update_header(bs); 4704 if (ret < 0) { 4705 s->qcow_version = current_version; 4706 error_setg_errno(errp, -ret, "Failed to update the image header"); 4707 return ret; 4708 } 4709 return 0; 4710 } 4711 4712 typedef enum Qcow2AmendOperation { 4713 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 4714 * statically initialized to so that the helper CB can discern the first 4715 * invocation from an operation change */ 4716 QCOW2_NO_OPERATION = 0, 4717 4718 QCOW2_CHANGING_REFCOUNT_ORDER, 4719 QCOW2_DOWNGRADING, 4720 } Qcow2AmendOperation; 4721 4722 typedef struct Qcow2AmendHelperCBInfo { 4723 /* The code coordinating the amend operations should only modify 4724 * these four fields; the rest will be managed by the CB */ 4725 BlockDriverAmendStatusCB *original_status_cb; 4726 void *original_cb_opaque; 4727 4728 Qcow2AmendOperation current_operation; 4729 4730 /* Total number of operations to perform (only set once) */ 4731 int total_operations; 4732 4733 /* The following fields are managed by the CB */ 4734 4735 /* Number of operations completed */ 4736 int operations_completed; 4737 4738 /* Cumulative offset of all completed operations */ 4739 int64_t offset_completed; 4740 4741 Qcow2AmendOperation last_operation; 4742 int64_t last_work_size; 4743 } Qcow2AmendHelperCBInfo; 4744 4745 static void qcow2_amend_helper_cb(BlockDriverState *bs, 4746 int64_t operation_offset, 4747 int64_t operation_work_size, void *opaque) 4748 { 4749 Qcow2AmendHelperCBInfo *info = opaque; 4750 int64_t current_work_size; 4751 int64_t projected_work_size; 4752 4753 if (info->current_operation != info->last_operation) { 4754 if (info->last_operation != QCOW2_NO_OPERATION) { 4755 info->offset_completed += info->last_work_size; 4756 info->operations_completed++; 4757 } 4758 4759 info->last_operation = info->current_operation; 4760 } 4761 4762 assert(info->total_operations > 0); 4763 assert(info->operations_completed < info->total_operations); 4764 4765 info->last_work_size = operation_work_size; 4766 4767 current_work_size = info->offset_completed + operation_work_size; 4768 4769 /* current_work_size is the total work size for (operations_completed + 1) 4770 * operations (which includes this one), so multiply it by the number of 4771 * operations not covered and divide it by the number of operations 4772 * covered to get a projection for the operations not covered */ 4773 projected_work_size = current_work_size * (info->total_operations - 4774 info->operations_completed - 1) 4775 / (info->operations_completed + 1); 4776 4777 info->original_status_cb(bs, info->offset_completed + operation_offset, 4778 current_work_size + projected_work_size, 4779 info->original_cb_opaque); 4780 } 4781 4782 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4783 BlockDriverAmendStatusCB *status_cb, 4784 void *cb_opaque, 4785 Error **errp) 4786 { 4787 BDRVQcow2State *s = bs->opaque; 4788 int old_version = s->qcow_version, new_version = old_version; 4789 uint64_t new_size = 0; 4790 const char *backing_file = NULL, *backing_format = NULL, *data_file = NULL; 4791 bool lazy_refcounts = s->use_lazy_refcounts; 4792 bool data_file_raw = data_file_is_raw(bs); 4793 const char *compat = NULL; 4794 uint64_t cluster_size = s->cluster_size; 4795 bool encrypt; 4796 int encformat; 4797 int refcount_bits = s->refcount_bits; 4798 int ret; 4799 QemuOptDesc *desc = opts->list->desc; 4800 Qcow2AmendHelperCBInfo helper_cb_info; 4801 4802 while (desc && desc->name) { 4803 if (!qemu_opt_find(opts, desc->name)) { 4804 /* only change explicitly defined options */ 4805 desc++; 4806 continue; 4807 } 4808 4809 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4810 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4811 if (!compat) { 4812 /* preserve default */ 4813 } else if (!strcmp(compat, "0.10")) { 4814 new_version = 2; 4815 } else if (!strcmp(compat, "1.1")) { 4816 new_version = 3; 4817 } else { 4818 error_setg(errp, "Unknown compatibility level %s", compat); 4819 return -EINVAL; 4820 } 4821 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4822 error_setg(errp, "Cannot change preallocation mode"); 4823 return -ENOTSUP; 4824 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4825 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4826 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4827 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4828 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4829 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4830 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4831 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4832 !!s->crypto); 4833 4834 if (encrypt != !!s->crypto) { 4835 error_setg(errp, 4836 "Changing the encryption flag is not supported"); 4837 return -ENOTSUP; 4838 } 4839 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4840 encformat = qcow2_crypt_method_from_format( 4841 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4842 4843 if (encformat != s->crypt_method_header) { 4844 error_setg(errp, 4845 "Changing the encryption format is not supported"); 4846 return -ENOTSUP; 4847 } 4848 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4849 error_setg(errp, 4850 "Changing the encryption parameters is not supported"); 4851 return -ENOTSUP; 4852 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4853 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4854 cluster_size); 4855 if (cluster_size != s->cluster_size) { 4856 error_setg(errp, "Changing the cluster size is not supported"); 4857 return -ENOTSUP; 4858 } 4859 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4860 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4861 lazy_refcounts); 4862 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4863 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4864 refcount_bits); 4865 4866 if (refcount_bits <= 0 || refcount_bits > 64 || 4867 !is_power_of_2(refcount_bits)) 4868 { 4869 error_setg(errp, "Refcount width must be a power of two and " 4870 "may not exceed 64 bits"); 4871 return -EINVAL; 4872 } 4873 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) { 4874 data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE); 4875 if (data_file && !has_data_file(bs)) { 4876 error_setg(errp, "data-file can only be set for images that " 4877 "use an external data file"); 4878 return -EINVAL; 4879 } 4880 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) { 4881 data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW, 4882 data_file_raw); 4883 if (data_file_raw && !data_file_is_raw(bs)) { 4884 error_setg(errp, "data-file-raw cannot be set on existing " 4885 "images"); 4886 return -EINVAL; 4887 } 4888 } else { 4889 /* if this point is reached, this probably means a new option was 4890 * added without having it covered here */ 4891 abort(); 4892 } 4893 4894 desc++; 4895 } 4896 4897 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4898 .original_status_cb = status_cb, 4899 .original_cb_opaque = cb_opaque, 4900 .total_operations = (new_version < old_version) 4901 + (s->refcount_bits != refcount_bits) 4902 }; 4903 4904 /* Upgrade first (some features may require compat=1.1) */ 4905 if (new_version > old_version) { 4906 s->qcow_version = new_version; 4907 ret = qcow2_update_header(bs); 4908 if (ret < 0) { 4909 s->qcow_version = old_version; 4910 error_setg_errno(errp, -ret, "Failed to update the image header"); 4911 return ret; 4912 } 4913 } 4914 4915 if (s->refcount_bits != refcount_bits) { 4916 int refcount_order = ctz32(refcount_bits); 4917 4918 if (new_version < 3 && refcount_bits != 16) { 4919 error_setg(errp, "Refcount widths other than 16 bits require " 4920 "compatibility level 1.1 or above (use compat=1.1 or " 4921 "greater)"); 4922 return -EINVAL; 4923 } 4924 4925 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4926 ret = qcow2_change_refcount_order(bs, refcount_order, 4927 &qcow2_amend_helper_cb, 4928 &helper_cb_info, errp); 4929 if (ret < 0) { 4930 return ret; 4931 } 4932 } 4933 4934 /* data-file-raw blocks backing files, so clear it first if requested */ 4935 if (data_file_raw) { 4936 s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW; 4937 } else { 4938 s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW; 4939 } 4940 4941 if (data_file) { 4942 g_free(s->image_data_file); 4943 s->image_data_file = *data_file ? g_strdup(data_file) : NULL; 4944 } 4945 4946 ret = qcow2_update_header(bs); 4947 if (ret < 0) { 4948 error_setg_errno(errp, -ret, "Failed to update the image header"); 4949 return ret; 4950 } 4951 4952 if (backing_file || backing_format) { 4953 ret = qcow2_change_backing_file(bs, 4954 backing_file ?: s->image_backing_file, 4955 backing_format ?: s->image_backing_format); 4956 if (ret < 0) { 4957 error_setg_errno(errp, -ret, "Failed to change the backing file"); 4958 return ret; 4959 } 4960 } 4961 4962 if (s->use_lazy_refcounts != lazy_refcounts) { 4963 if (lazy_refcounts) { 4964 if (new_version < 3) { 4965 error_setg(errp, "Lazy refcounts only supported with " 4966 "compatibility level 1.1 and above (use compat=1.1 " 4967 "or greater)"); 4968 return -EINVAL; 4969 } 4970 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4971 ret = qcow2_update_header(bs); 4972 if (ret < 0) { 4973 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4974 error_setg_errno(errp, -ret, "Failed to update the image header"); 4975 return ret; 4976 } 4977 s->use_lazy_refcounts = true; 4978 } else { 4979 /* make image clean first */ 4980 ret = qcow2_mark_clean(bs); 4981 if (ret < 0) { 4982 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4983 return ret; 4984 } 4985 /* now disallow lazy refcounts */ 4986 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4987 ret = qcow2_update_header(bs); 4988 if (ret < 0) { 4989 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4990 error_setg_errno(errp, -ret, "Failed to update the image header"); 4991 return ret; 4992 } 4993 s->use_lazy_refcounts = false; 4994 } 4995 } 4996 4997 if (new_size) { 4998 BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); 4999 ret = blk_insert_bs(blk, bs, errp); 5000 if (ret < 0) { 5001 blk_unref(blk); 5002 return ret; 5003 } 5004 5005 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp); 5006 blk_unref(blk); 5007 if (ret < 0) { 5008 return ret; 5009 } 5010 } 5011 5012 /* Downgrade last (so unsupported features can be removed before) */ 5013 if (new_version < old_version) { 5014 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 5015 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 5016 &helper_cb_info, errp); 5017 if (ret < 0) { 5018 return ret; 5019 } 5020 } 5021 5022 return 0; 5023 } 5024 5025 /* 5026 * If offset or size are negative, respectively, they will not be included in 5027 * the BLOCK_IMAGE_CORRUPTED event emitted. 5028 * fatal will be ignored for read-only BDS; corruptions found there will always 5029 * be considered non-fatal. 5030 */ 5031 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 5032 int64_t size, const char *message_format, ...) 5033 { 5034 BDRVQcow2State *s = bs->opaque; 5035 const char *node_name; 5036 char *message; 5037 va_list ap; 5038 5039 fatal = fatal && bdrv_is_writable(bs); 5040 5041 if (s->signaled_corruption && 5042 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 5043 { 5044 return; 5045 } 5046 5047 va_start(ap, message_format); 5048 message = g_strdup_vprintf(message_format, ap); 5049 va_end(ap); 5050 5051 if (fatal) { 5052 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 5053 "corruption events will be suppressed\n", message); 5054 } else { 5055 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 5056 "corruption events will be suppressed\n", message); 5057 } 5058 5059 node_name = bdrv_get_node_name(bs); 5060 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 5061 *node_name != '\0', node_name, 5062 message, offset >= 0, offset, 5063 size >= 0, size, 5064 fatal); 5065 g_free(message); 5066 5067 if (fatal) { 5068 qcow2_mark_corrupt(bs); 5069 bs->drv = NULL; /* make BDS unusable */ 5070 } 5071 5072 s->signaled_corruption = true; 5073 } 5074 5075 static QemuOptsList qcow2_create_opts = { 5076 .name = "qcow2-create-opts", 5077 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 5078 .desc = { 5079 { 5080 .name = BLOCK_OPT_SIZE, 5081 .type = QEMU_OPT_SIZE, 5082 .help = "Virtual disk size" 5083 }, 5084 { 5085 .name = BLOCK_OPT_COMPAT_LEVEL, 5086 .type = QEMU_OPT_STRING, 5087 .help = "Compatibility level (0.10 or 1.1)" 5088 }, 5089 { 5090 .name = BLOCK_OPT_BACKING_FILE, 5091 .type = QEMU_OPT_STRING, 5092 .help = "File name of a base image" 5093 }, 5094 { 5095 .name = BLOCK_OPT_BACKING_FMT, 5096 .type = QEMU_OPT_STRING, 5097 .help = "Image format of the base image" 5098 }, 5099 { 5100 .name = BLOCK_OPT_DATA_FILE, 5101 .type = QEMU_OPT_STRING, 5102 .help = "File name of an external data file" 5103 }, 5104 { 5105 .name = BLOCK_OPT_DATA_FILE_RAW, 5106 .type = QEMU_OPT_BOOL, 5107 .help = "The external data file must stay valid as a raw image" 5108 }, 5109 { 5110 .name = BLOCK_OPT_ENCRYPT, 5111 .type = QEMU_OPT_BOOL, 5112 .help = "Encrypt the image with format 'aes'. (Deprecated " 5113 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 5114 }, 5115 { 5116 .name = BLOCK_OPT_ENCRYPT_FORMAT, 5117 .type = QEMU_OPT_STRING, 5118 .help = "Encrypt the image, format choices: 'aes', 'luks'", 5119 }, 5120 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 5121 "ID of secret providing qcow AES key or LUKS passphrase"), 5122 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 5123 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 5124 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 5125 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 5126 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 5127 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 5128 { 5129 .name = BLOCK_OPT_CLUSTER_SIZE, 5130 .type = QEMU_OPT_SIZE, 5131 .help = "qcow2 cluster size", 5132 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 5133 }, 5134 { 5135 .name = BLOCK_OPT_PREALLOC, 5136 .type = QEMU_OPT_STRING, 5137 .help = "Preallocation mode (allowed values: off, metadata, " 5138 "falloc, full)" 5139 }, 5140 { 5141 .name = BLOCK_OPT_LAZY_REFCOUNTS, 5142 .type = QEMU_OPT_BOOL, 5143 .help = "Postpone refcount updates", 5144 .def_value_str = "off" 5145 }, 5146 { 5147 .name = BLOCK_OPT_REFCOUNT_BITS, 5148 .type = QEMU_OPT_NUMBER, 5149 .help = "Width of a reference count entry in bits", 5150 .def_value_str = "16" 5151 }, 5152 { /* end of list */ } 5153 } 5154 }; 5155 5156 static const char *const qcow2_strong_runtime_opts[] = { 5157 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 5158 5159 NULL 5160 }; 5161 5162 BlockDriver bdrv_qcow2 = { 5163 .format_name = "qcow2", 5164 .instance_size = sizeof(BDRVQcow2State), 5165 .bdrv_probe = qcow2_probe, 5166 .bdrv_open = qcow2_open, 5167 .bdrv_close = qcow2_close, 5168 .bdrv_reopen_prepare = qcow2_reopen_prepare, 5169 .bdrv_reopen_commit = qcow2_reopen_commit, 5170 .bdrv_reopen_abort = qcow2_reopen_abort, 5171 .bdrv_join_options = qcow2_join_options, 5172 .bdrv_child_perm = bdrv_format_default_perms, 5173 .bdrv_co_create_opts = qcow2_co_create_opts, 5174 .bdrv_co_create = qcow2_co_create, 5175 .bdrv_has_zero_init = bdrv_has_zero_init_1, 5176 .bdrv_co_block_status = qcow2_co_block_status, 5177 5178 .bdrv_co_preadv = qcow2_co_preadv, 5179 .bdrv_co_pwritev = qcow2_co_pwritev, 5180 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 5181 5182 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 5183 .bdrv_co_pdiscard = qcow2_co_pdiscard, 5184 .bdrv_co_copy_range_from = qcow2_co_copy_range_from, 5185 .bdrv_co_copy_range_to = qcow2_co_copy_range_to, 5186 .bdrv_co_truncate = qcow2_co_truncate, 5187 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 5188 .bdrv_make_empty = qcow2_make_empty, 5189 5190 .bdrv_snapshot_create = qcow2_snapshot_create, 5191 .bdrv_snapshot_goto = qcow2_snapshot_goto, 5192 .bdrv_snapshot_delete = qcow2_snapshot_delete, 5193 .bdrv_snapshot_list = qcow2_snapshot_list, 5194 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 5195 .bdrv_measure = qcow2_measure, 5196 .bdrv_get_info = qcow2_get_info, 5197 .bdrv_get_specific_info = qcow2_get_specific_info, 5198 5199 .bdrv_save_vmstate = qcow2_save_vmstate, 5200 .bdrv_load_vmstate = qcow2_load_vmstate, 5201 5202 .supports_backing = true, 5203 .bdrv_change_backing_file = qcow2_change_backing_file, 5204 5205 .bdrv_refresh_limits = qcow2_refresh_limits, 5206 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, 5207 .bdrv_inactivate = qcow2_inactivate, 5208 5209 .create_opts = &qcow2_create_opts, 5210 .strong_runtime_opts = qcow2_strong_runtime_opts, 5211 .mutable_opts = mutable_opts, 5212 .bdrv_co_check = qcow2_co_check, 5213 .bdrv_amend_options = qcow2_amend_options, 5214 5215 .bdrv_detach_aio_context = qcow2_detach_aio_context, 5216 .bdrv_attach_aio_context = qcow2_attach_aio_context, 5217 5218 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 5219 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 5220 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 5221 }; 5222 5223 static void bdrv_qcow2_init(void) 5224 { 5225 bdrv_register(&bdrv_qcow2); 5226 } 5227 5228 block_init(bdrv_qcow2_init); 5229