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/main-loop.h" 30 #include "qemu/module.h" 31 #include "qcow2.h" 32 #include "qemu/error-report.h" 33 #include "qapi/error.h" 34 #include "qapi/qapi-events-block-core.h" 35 #include "qapi/qmp/qdict.h" 36 #include "qapi/qmp/qstring.h" 37 #include "trace.h" 38 #include "qemu/option_int.h" 39 #include "qemu/cutils.h" 40 #include "qemu/bswap.h" 41 #include "qapi/qobject-input-visitor.h" 42 #include "qapi/qapi-visit-block-core.h" 43 #include "crypto.h" 44 45 /* 46 Differences with QCOW: 47 48 - Support for multiple incremental snapshots. 49 - Memory management by reference counts. 50 - Clusters which have a reference count of one have the bit 51 QCOW_OFLAG_COPIED to optimize write performance. 52 - Size of compressed clusters is stored in sectors to reduce bit usage 53 in the cluster offsets. 54 - Support for storing additional data (such as the VM state) in the 55 snapshots. 56 - If a backing store is used, the cluster size is not constrained 57 (could be backported to QCOW). 58 - L2 tables have always a size of one cluster. 59 */ 60 61 62 typedef struct { 63 uint32_t magic; 64 uint32_t len; 65 } QEMU_PACKED QCowExtension; 66 67 #define QCOW2_EXT_MAGIC_END 0 68 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 69 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 70 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 71 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 72 #define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441 73 74 static int coroutine_fn 75 qcow2_co_preadv_compressed(BlockDriverState *bs, 76 uint64_t file_cluster_offset, 77 uint64_t offset, 78 uint64_t bytes, 79 QEMUIOVector *qiov); 80 81 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 82 { 83 const QCowHeader *cow_header = (const void *)buf; 84 85 if (buf_size >= sizeof(QCowHeader) && 86 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 87 be32_to_cpu(cow_header->version) >= 2) 88 return 100; 89 else 90 return 0; 91 } 92 93 94 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 95 uint8_t *buf, size_t buflen, 96 void *opaque, Error **errp) 97 { 98 BlockDriverState *bs = opaque; 99 BDRVQcow2State *s = bs->opaque; 100 ssize_t ret; 101 102 if ((offset + buflen) > s->crypto_header.length) { 103 error_setg(errp, "Request for data outside of extension header"); 104 return -1; 105 } 106 107 ret = bdrv_pread(bs->file, 108 s->crypto_header.offset + offset, buf, buflen); 109 if (ret < 0) { 110 error_setg_errno(errp, -ret, "Could not read encryption header"); 111 return -1; 112 } 113 return ret; 114 } 115 116 117 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 118 void *opaque, Error **errp) 119 { 120 BlockDriverState *bs = opaque; 121 BDRVQcow2State *s = bs->opaque; 122 int64_t ret; 123 int64_t clusterlen; 124 125 ret = qcow2_alloc_clusters(bs, headerlen); 126 if (ret < 0) { 127 error_setg_errno(errp, -ret, 128 "Cannot allocate cluster for LUKS header size %zu", 129 headerlen); 130 return -1; 131 } 132 133 s->crypto_header.length = headerlen; 134 s->crypto_header.offset = ret; 135 136 /* Zero fill remaining space in cluster so it has predictable 137 * content in case of future spec changes */ 138 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 139 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0); 140 ret = bdrv_pwrite_zeroes(bs->file, 141 ret + headerlen, 142 clusterlen - headerlen, 0); 143 if (ret < 0) { 144 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 145 return -1; 146 } 147 148 return ret; 149 } 150 151 152 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 153 const uint8_t *buf, size_t buflen, 154 void *opaque, Error **errp) 155 { 156 BlockDriverState *bs = opaque; 157 BDRVQcow2State *s = bs->opaque; 158 ssize_t ret; 159 160 if ((offset + buflen) > s->crypto_header.length) { 161 error_setg(errp, "Request for data outside of extension header"); 162 return -1; 163 } 164 165 ret = bdrv_pwrite(bs->file, 166 s->crypto_header.offset + offset, buf, buflen); 167 if (ret < 0) { 168 error_setg_errno(errp, -ret, "Could not read encryption header"); 169 return -1; 170 } 171 return ret; 172 } 173 174 175 /* 176 * read qcow2 extension and fill bs 177 * start reading from start_offset 178 * finish reading upon magic of value 0 or when end_offset reached 179 * unknown magic is skipped (future extension this version knows nothing about) 180 * return 0 upon success, non-0 otherwise 181 */ 182 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 183 uint64_t end_offset, void **p_feature_table, 184 int flags, bool *need_update_header, 185 Error **errp) 186 { 187 BDRVQcow2State *s = bs->opaque; 188 QCowExtension ext; 189 uint64_t offset; 190 int ret; 191 Qcow2BitmapHeaderExt bitmaps_ext; 192 193 if (need_update_header != NULL) { 194 *need_update_header = false; 195 } 196 197 #ifdef DEBUG_EXT 198 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 199 #endif 200 offset = start_offset; 201 while (offset < end_offset) { 202 203 #ifdef DEBUG_EXT 204 /* Sanity check */ 205 if (offset > s->cluster_size) 206 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 207 208 printf("attempting to read extended header in offset %lu\n", offset); 209 #endif 210 211 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 212 if (ret < 0) { 213 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 214 "pread fail from offset %" PRIu64, offset); 215 return 1; 216 } 217 ext.magic = be32_to_cpu(ext.magic); 218 ext.len = be32_to_cpu(ext.len); 219 offset += sizeof(ext); 220 #ifdef DEBUG_EXT 221 printf("ext.magic = 0x%x\n", ext.magic); 222 #endif 223 if (offset > end_offset || ext.len > end_offset - offset) { 224 error_setg(errp, "Header extension too large"); 225 return -EINVAL; 226 } 227 228 switch (ext.magic) { 229 case QCOW2_EXT_MAGIC_END: 230 return 0; 231 232 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 233 if (ext.len >= sizeof(bs->backing_format)) { 234 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 235 " too large (>=%zu)", ext.len, 236 sizeof(bs->backing_format)); 237 return 2; 238 } 239 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 240 if (ret < 0) { 241 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 242 "Could not read format name"); 243 return 3; 244 } 245 bs->backing_format[ext.len] = '\0'; 246 s->image_backing_format = g_strdup(bs->backing_format); 247 #ifdef DEBUG_EXT 248 printf("Qcow2: Got format extension %s\n", bs->backing_format); 249 #endif 250 break; 251 252 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 253 if (p_feature_table != NULL) { 254 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 255 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 256 if (ret < 0) { 257 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 258 "Could not read table"); 259 return ret; 260 } 261 262 *p_feature_table = feature_table; 263 } 264 break; 265 266 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 267 unsigned int cflags = 0; 268 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 269 error_setg(errp, "CRYPTO header extension only " 270 "expected with LUKS encryption method"); 271 return -EINVAL; 272 } 273 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 274 error_setg(errp, "CRYPTO header extension size %u, " 275 "but expected size %zu", ext.len, 276 sizeof(Qcow2CryptoHeaderExtension)); 277 return -EINVAL; 278 } 279 280 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 281 if (ret < 0) { 282 error_setg_errno(errp, -ret, 283 "Unable to read CRYPTO header extension"); 284 return ret; 285 } 286 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 287 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 288 289 if ((s->crypto_header.offset % s->cluster_size) != 0) { 290 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 291 "not a multiple of cluster size '%u'", 292 s->crypto_header.offset, s->cluster_size); 293 return -EINVAL; 294 } 295 296 if (flags & BDRV_O_NO_IO) { 297 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 298 } 299 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 300 qcow2_crypto_hdr_read_func, 301 bs, cflags, QCOW2_MAX_THREADS, errp); 302 if (!s->crypto) { 303 return -EINVAL; 304 } 305 } break; 306 307 case QCOW2_EXT_MAGIC_BITMAPS: 308 if (ext.len != sizeof(bitmaps_ext)) { 309 error_setg_errno(errp, -ret, "bitmaps_ext: " 310 "Invalid extension length"); 311 return -EINVAL; 312 } 313 314 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 315 if (s->qcow_version < 3) { 316 /* Let's be a bit more specific */ 317 warn_report("This qcow2 v2 image contains bitmaps, but " 318 "they may have been modified by a program " 319 "without persistent bitmap support; so now " 320 "they must all be considered inconsistent"); 321 } else { 322 warn_report("a program lacking bitmap support " 323 "modified this file, so all bitmaps are now " 324 "considered inconsistent"); 325 } 326 error_printf("Some clusters may be leaked, " 327 "run 'qemu-img check -r' on the image " 328 "file to fix."); 329 if (need_update_header != NULL) { 330 /* Updating is needed to drop invalid bitmap extension. */ 331 *need_update_header = true; 332 } 333 break; 334 } 335 336 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 337 if (ret < 0) { 338 error_setg_errno(errp, -ret, "bitmaps_ext: " 339 "Could not read ext header"); 340 return ret; 341 } 342 343 if (bitmaps_ext.reserved32 != 0) { 344 error_setg_errno(errp, -ret, "bitmaps_ext: " 345 "Reserved field is not zero"); 346 return -EINVAL; 347 } 348 349 bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps); 350 bitmaps_ext.bitmap_directory_size = 351 be64_to_cpu(bitmaps_ext.bitmap_directory_size); 352 bitmaps_ext.bitmap_directory_offset = 353 be64_to_cpu(bitmaps_ext.bitmap_directory_offset); 354 355 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 356 error_setg(errp, 357 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 358 "exceeding the QEMU supported maximum of %d", 359 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 360 return -EINVAL; 361 } 362 363 if (bitmaps_ext.nb_bitmaps == 0) { 364 error_setg(errp, "found bitmaps extension with zero bitmaps"); 365 return -EINVAL; 366 } 367 368 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 369 error_setg(errp, "bitmaps_ext: " 370 "invalid bitmap directory offset"); 371 return -EINVAL; 372 } 373 374 if (bitmaps_ext.bitmap_directory_size > 375 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 376 error_setg(errp, "bitmaps_ext: " 377 "bitmap directory size (%" PRIu64 ") exceeds " 378 "the maximum supported size (%d)", 379 bitmaps_ext.bitmap_directory_size, 380 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 381 return -EINVAL; 382 } 383 384 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 385 s->bitmap_directory_offset = 386 bitmaps_ext.bitmap_directory_offset; 387 s->bitmap_directory_size = 388 bitmaps_ext.bitmap_directory_size; 389 390 #ifdef DEBUG_EXT 391 printf("Qcow2: Got bitmaps extension: " 392 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 393 s->bitmap_directory_offset, s->nb_bitmaps); 394 #endif 395 break; 396 397 case QCOW2_EXT_MAGIC_DATA_FILE: 398 { 399 s->image_data_file = g_malloc0(ext.len + 1); 400 ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len); 401 if (ret < 0) { 402 error_setg_errno(errp, -ret, 403 "ERROR: Could not read data file name"); 404 return ret; 405 } 406 #ifdef DEBUG_EXT 407 printf("Qcow2: Got external data file %s\n", s->image_data_file); 408 #endif 409 break; 410 } 411 412 default: 413 /* unknown magic - save it in case we need to rewrite the header */ 414 /* If you add a new feature, make sure to also update the fast 415 * path of qcow2_make_empty() to deal with it. */ 416 { 417 Qcow2UnknownHeaderExtension *uext; 418 419 uext = g_malloc0(sizeof(*uext) + ext.len); 420 uext->magic = ext.magic; 421 uext->len = ext.len; 422 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 423 424 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 425 if (ret < 0) { 426 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 427 "Could not read data"); 428 return ret; 429 } 430 } 431 break; 432 } 433 434 offset += ((ext.len + 7) & ~7); 435 } 436 437 return 0; 438 } 439 440 static void cleanup_unknown_header_ext(BlockDriverState *bs) 441 { 442 BDRVQcow2State *s = bs->opaque; 443 Qcow2UnknownHeaderExtension *uext, *next; 444 445 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 446 QLIST_REMOVE(uext, next); 447 g_free(uext); 448 } 449 } 450 451 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 452 uint64_t mask) 453 { 454 char *features = g_strdup(""); 455 char *old; 456 457 while (table && table->name[0] != '\0') { 458 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 459 if (mask & (1ULL << table->bit)) { 460 old = features; 461 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 462 table->name); 463 g_free(old); 464 mask &= ~(1ULL << table->bit); 465 } 466 } 467 table++; 468 } 469 470 if (mask) { 471 old = features; 472 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 473 old, *old ? ", " : "", mask); 474 g_free(old); 475 } 476 477 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 478 g_free(features); 479 } 480 481 /* 482 * Sets the dirty bit and flushes afterwards if necessary. 483 * 484 * The incompatible_features bit is only set if the image file header was 485 * updated successfully. Therefore it is not required to check the return 486 * value of this function. 487 */ 488 int qcow2_mark_dirty(BlockDriverState *bs) 489 { 490 BDRVQcow2State *s = bs->opaque; 491 uint64_t val; 492 int ret; 493 494 assert(s->qcow_version >= 3); 495 496 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 497 return 0; /* already dirty */ 498 } 499 500 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 501 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 502 &val, sizeof(val)); 503 if (ret < 0) { 504 return ret; 505 } 506 ret = bdrv_flush(bs->file->bs); 507 if (ret < 0) { 508 return ret; 509 } 510 511 /* Only treat image as dirty if the header was updated successfully */ 512 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 513 return 0; 514 } 515 516 /* 517 * Clears the dirty bit and flushes before if necessary. Only call this 518 * function when there are no pending requests, it does not guard against 519 * concurrent requests dirtying the image. 520 */ 521 static int qcow2_mark_clean(BlockDriverState *bs) 522 { 523 BDRVQcow2State *s = bs->opaque; 524 525 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 526 int ret; 527 528 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 529 530 ret = qcow2_flush_caches(bs); 531 if (ret < 0) { 532 return ret; 533 } 534 535 return qcow2_update_header(bs); 536 } 537 return 0; 538 } 539 540 /* 541 * Marks the image as corrupt. 542 */ 543 int qcow2_mark_corrupt(BlockDriverState *bs) 544 { 545 BDRVQcow2State *s = bs->opaque; 546 547 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 548 return qcow2_update_header(bs); 549 } 550 551 /* 552 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 553 * before if necessary. 554 */ 555 int qcow2_mark_consistent(BlockDriverState *bs) 556 { 557 BDRVQcow2State *s = bs->opaque; 558 559 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 560 int ret = qcow2_flush_caches(bs); 561 if (ret < 0) { 562 return ret; 563 } 564 565 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 566 return qcow2_update_header(bs); 567 } 568 return 0; 569 } 570 571 static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, 572 BdrvCheckResult *result, 573 BdrvCheckMode fix) 574 { 575 int ret = qcow2_check_refcounts(bs, result, fix); 576 if (ret < 0) { 577 return ret; 578 } 579 580 if (fix && result->check_errors == 0 && result->corruptions == 0) { 581 ret = qcow2_mark_clean(bs); 582 if (ret < 0) { 583 return ret; 584 } 585 return qcow2_mark_consistent(bs); 586 } 587 return ret; 588 } 589 590 static int coroutine_fn qcow2_co_check(BlockDriverState *bs, 591 BdrvCheckResult *result, 592 BdrvCheckMode fix) 593 { 594 BDRVQcow2State *s = bs->opaque; 595 int ret; 596 597 qemu_co_mutex_lock(&s->lock); 598 ret = qcow2_co_check_locked(bs, result, fix); 599 qemu_co_mutex_unlock(&s->lock); 600 return ret; 601 } 602 603 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, 604 uint64_t entries, size_t entry_len, 605 int64_t max_size_bytes, const char *table_name, 606 Error **errp) 607 { 608 BDRVQcow2State *s = bs->opaque; 609 610 if (entries > max_size_bytes / entry_len) { 611 error_setg(errp, "%s too large", table_name); 612 return -EFBIG; 613 } 614 615 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 616 * because values will be passed to qemu functions taking int64_t. */ 617 if ((INT64_MAX - entries * entry_len < offset) || 618 (offset_into_cluster(s, offset) != 0)) { 619 error_setg(errp, "%s offset invalid", table_name); 620 return -EINVAL; 621 } 622 623 return 0; 624 } 625 626 static const char *const mutable_opts[] = { 627 QCOW2_OPT_LAZY_REFCOUNTS, 628 QCOW2_OPT_DISCARD_REQUEST, 629 QCOW2_OPT_DISCARD_SNAPSHOT, 630 QCOW2_OPT_DISCARD_OTHER, 631 QCOW2_OPT_OVERLAP, 632 QCOW2_OPT_OVERLAP_TEMPLATE, 633 QCOW2_OPT_OVERLAP_MAIN_HEADER, 634 QCOW2_OPT_OVERLAP_ACTIVE_L1, 635 QCOW2_OPT_OVERLAP_ACTIVE_L2, 636 QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 637 QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 638 QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 639 QCOW2_OPT_OVERLAP_INACTIVE_L1, 640 QCOW2_OPT_OVERLAP_INACTIVE_L2, 641 QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 642 QCOW2_OPT_CACHE_SIZE, 643 QCOW2_OPT_L2_CACHE_SIZE, 644 QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 645 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 646 QCOW2_OPT_CACHE_CLEAN_INTERVAL, 647 NULL 648 }; 649 650 static QemuOptsList qcow2_runtime_opts = { 651 .name = "qcow2", 652 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 653 .desc = { 654 { 655 .name = QCOW2_OPT_LAZY_REFCOUNTS, 656 .type = QEMU_OPT_BOOL, 657 .help = "Postpone refcount updates", 658 }, 659 { 660 .name = QCOW2_OPT_DISCARD_REQUEST, 661 .type = QEMU_OPT_BOOL, 662 .help = "Pass guest discard requests to the layer below", 663 }, 664 { 665 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 666 .type = QEMU_OPT_BOOL, 667 .help = "Generate discard requests when snapshot related space " 668 "is freed", 669 }, 670 { 671 .name = QCOW2_OPT_DISCARD_OTHER, 672 .type = QEMU_OPT_BOOL, 673 .help = "Generate discard requests when other clusters are freed", 674 }, 675 { 676 .name = QCOW2_OPT_OVERLAP, 677 .type = QEMU_OPT_STRING, 678 .help = "Selects which overlap checks to perform from a range of " 679 "templates (none, constant, cached, all)", 680 }, 681 { 682 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 683 .type = QEMU_OPT_STRING, 684 .help = "Selects which overlap checks to perform from a range of " 685 "templates (none, constant, cached, all)", 686 }, 687 { 688 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 689 .type = QEMU_OPT_BOOL, 690 .help = "Check for unintended writes into the main qcow2 header", 691 }, 692 { 693 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 694 .type = QEMU_OPT_BOOL, 695 .help = "Check for unintended writes into the active L1 table", 696 }, 697 { 698 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 699 .type = QEMU_OPT_BOOL, 700 .help = "Check for unintended writes into an active L2 table", 701 }, 702 { 703 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 704 .type = QEMU_OPT_BOOL, 705 .help = "Check for unintended writes into the refcount table", 706 }, 707 { 708 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 709 .type = QEMU_OPT_BOOL, 710 .help = "Check for unintended writes into a refcount block", 711 }, 712 { 713 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 714 .type = QEMU_OPT_BOOL, 715 .help = "Check for unintended writes into the snapshot table", 716 }, 717 { 718 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 719 .type = QEMU_OPT_BOOL, 720 .help = "Check for unintended writes into an inactive L1 table", 721 }, 722 { 723 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 724 .type = QEMU_OPT_BOOL, 725 .help = "Check for unintended writes into an inactive L2 table", 726 }, 727 { 728 .name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 729 .type = QEMU_OPT_BOOL, 730 .help = "Check for unintended writes into the bitmap directory", 731 }, 732 { 733 .name = QCOW2_OPT_CACHE_SIZE, 734 .type = QEMU_OPT_SIZE, 735 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 736 "cache size", 737 }, 738 { 739 .name = QCOW2_OPT_L2_CACHE_SIZE, 740 .type = QEMU_OPT_SIZE, 741 .help = "Maximum L2 table cache size", 742 }, 743 { 744 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 745 .type = QEMU_OPT_SIZE, 746 .help = "Size of each entry in the L2 cache", 747 }, 748 { 749 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 750 .type = QEMU_OPT_SIZE, 751 .help = "Maximum refcount block cache size", 752 }, 753 { 754 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 755 .type = QEMU_OPT_NUMBER, 756 .help = "Clean unused cache entries after this time (in seconds)", 757 }, 758 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 759 "ID of secret providing qcow2 AES key or LUKS passphrase"), 760 { /* end of list */ } 761 }, 762 }; 763 764 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 765 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 766 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 767 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 768 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 769 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 770 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 771 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 772 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 773 [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 774 }; 775 776 static void cache_clean_timer_cb(void *opaque) 777 { 778 BlockDriverState *bs = opaque; 779 BDRVQcow2State *s = bs->opaque; 780 qcow2_cache_clean_unused(s->l2_table_cache); 781 qcow2_cache_clean_unused(s->refcount_block_cache); 782 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 783 (int64_t) s->cache_clean_interval * 1000); 784 } 785 786 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 787 { 788 BDRVQcow2State *s = bs->opaque; 789 if (s->cache_clean_interval > 0) { 790 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 791 SCALE_MS, cache_clean_timer_cb, 792 bs); 793 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 794 (int64_t) s->cache_clean_interval * 1000); 795 } 796 } 797 798 static void cache_clean_timer_del(BlockDriverState *bs) 799 { 800 BDRVQcow2State *s = bs->opaque; 801 if (s->cache_clean_timer) { 802 timer_del(s->cache_clean_timer); 803 timer_free(s->cache_clean_timer); 804 s->cache_clean_timer = NULL; 805 } 806 } 807 808 static void qcow2_detach_aio_context(BlockDriverState *bs) 809 { 810 cache_clean_timer_del(bs); 811 } 812 813 static void qcow2_attach_aio_context(BlockDriverState *bs, 814 AioContext *new_context) 815 { 816 cache_clean_timer_init(bs, new_context); 817 } 818 819 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 820 uint64_t *l2_cache_size, 821 uint64_t *l2_cache_entry_size, 822 uint64_t *refcount_cache_size, Error **errp) 823 { 824 BDRVQcow2State *s = bs->opaque; 825 uint64_t combined_cache_size, l2_cache_max_setting; 826 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 827 bool l2_cache_entry_size_set; 828 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; 829 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; 830 uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8); 831 832 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 833 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 834 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 835 l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE); 836 837 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 838 l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 839 DEFAULT_L2_CACHE_MAX_SIZE); 840 *refcount_cache_size = qemu_opt_get_size(opts, 841 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 842 843 *l2_cache_entry_size = qemu_opt_get_size( 844 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 845 846 *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting); 847 848 if (combined_cache_size_set) { 849 if (l2_cache_size_set && refcount_cache_size_set) { 850 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 851 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 852 "at the same time"); 853 return; 854 } else if (l2_cache_size_set && 855 (l2_cache_max_setting > combined_cache_size)) { 856 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 857 QCOW2_OPT_CACHE_SIZE); 858 return; 859 } else if (*refcount_cache_size > combined_cache_size) { 860 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 861 QCOW2_OPT_CACHE_SIZE); 862 return; 863 } 864 865 if (l2_cache_size_set) { 866 *refcount_cache_size = combined_cache_size - *l2_cache_size; 867 } else if (refcount_cache_size_set) { 868 *l2_cache_size = combined_cache_size - *refcount_cache_size; 869 } else { 870 /* Assign as much memory as possible to the L2 cache, and 871 * use the remainder for the refcount cache */ 872 if (combined_cache_size >= max_l2_cache + min_refcount_cache) { 873 *l2_cache_size = max_l2_cache; 874 *refcount_cache_size = combined_cache_size - *l2_cache_size; 875 } else { 876 *refcount_cache_size = 877 MIN(combined_cache_size, min_refcount_cache); 878 *l2_cache_size = combined_cache_size - *refcount_cache_size; 879 } 880 } 881 } 882 883 /* 884 * If the L2 cache is not enough to cover the whole disk then 885 * default to 4KB entries. Smaller entries reduce the cost of 886 * loads and evictions and increase I/O performance. 887 */ 888 if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) { 889 *l2_cache_entry_size = MIN(s->cluster_size, 4096); 890 } 891 892 /* l2_cache_size and refcount_cache_size are ensured to have at least 893 * their minimum values in qcow2_update_options_prepare() */ 894 895 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 896 *l2_cache_entry_size > s->cluster_size || 897 !is_power_of_2(*l2_cache_entry_size)) { 898 error_setg(errp, "L2 cache entry size must be a power of two " 899 "between %d and the cluster size (%d)", 900 1 << MIN_CLUSTER_BITS, s->cluster_size); 901 return; 902 } 903 } 904 905 typedef struct Qcow2ReopenState { 906 Qcow2Cache *l2_table_cache; 907 Qcow2Cache *refcount_block_cache; 908 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 909 bool use_lazy_refcounts; 910 int overlap_check; 911 bool discard_passthrough[QCOW2_DISCARD_MAX]; 912 uint64_t cache_clean_interval; 913 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 914 } Qcow2ReopenState; 915 916 static int qcow2_update_options_prepare(BlockDriverState *bs, 917 Qcow2ReopenState *r, 918 QDict *options, int flags, 919 Error **errp) 920 { 921 BDRVQcow2State *s = bs->opaque; 922 QemuOpts *opts = NULL; 923 const char *opt_overlap_check, *opt_overlap_check_template; 924 int overlap_check_template = 0; 925 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 926 int i; 927 const char *encryptfmt; 928 QDict *encryptopts = NULL; 929 Error *local_err = NULL; 930 int ret; 931 932 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 933 encryptfmt = qdict_get_try_str(encryptopts, "format"); 934 935 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 936 qemu_opts_absorb_qdict(opts, options, &local_err); 937 if (local_err) { 938 error_propagate(errp, local_err); 939 ret = -EINVAL; 940 goto fail; 941 } 942 943 /* get L2 table/refcount block cache size from command line options */ 944 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 945 &refcount_cache_size, &local_err); 946 if (local_err) { 947 error_propagate(errp, local_err); 948 ret = -EINVAL; 949 goto fail; 950 } 951 952 l2_cache_size /= l2_cache_entry_size; 953 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 954 l2_cache_size = MIN_L2_CACHE_SIZE; 955 } 956 if (l2_cache_size > INT_MAX) { 957 error_setg(errp, "L2 cache size too big"); 958 ret = -EINVAL; 959 goto fail; 960 } 961 962 refcount_cache_size /= s->cluster_size; 963 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 964 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 965 } 966 if (refcount_cache_size > INT_MAX) { 967 error_setg(errp, "Refcount cache size too big"); 968 ret = -EINVAL; 969 goto fail; 970 } 971 972 /* alloc new L2 table/refcount block cache, flush old one */ 973 if (s->l2_table_cache) { 974 ret = qcow2_cache_flush(bs, s->l2_table_cache); 975 if (ret) { 976 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 977 goto fail; 978 } 979 } 980 981 if (s->refcount_block_cache) { 982 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 983 if (ret) { 984 error_setg_errno(errp, -ret, 985 "Failed to flush the refcount block cache"); 986 goto fail; 987 } 988 } 989 990 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 991 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 992 l2_cache_entry_size); 993 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 994 s->cluster_size); 995 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 996 error_setg(errp, "Could not allocate metadata caches"); 997 ret = -ENOMEM; 998 goto fail; 999 } 1000 1001 /* New interval for cache cleanup timer */ 1002 r->cache_clean_interval = 1003 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 1004 DEFAULT_CACHE_CLEAN_INTERVAL); 1005 #ifndef CONFIG_LINUX 1006 if (r->cache_clean_interval != 0) { 1007 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 1008 " not supported on this host"); 1009 ret = -EINVAL; 1010 goto fail; 1011 } 1012 #endif 1013 if (r->cache_clean_interval > UINT_MAX) { 1014 error_setg(errp, "Cache clean interval too big"); 1015 ret = -EINVAL; 1016 goto fail; 1017 } 1018 1019 /* lazy-refcounts; flush if going from enabled to disabled */ 1020 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 1021 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 1022 if (r->use_lazy_refcounts && s->qcow_version < 3) { 1023 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 1024 "qemu 1.1 compatibility level"); 1025 ret = -EINVAL; 1026 goto fail; 1027 } 1028 1029 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 1030 ret = qcow2_mark_clean(bs); 1031 if (ret < 0) { 1032 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 1033 goto fail; 1034 } 1035 } 1036 1037 /* Overlap check options */ 1038 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 1039 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 1040 if (opt_overlap_check_template && opt_overlap_check && 1041 strcmp(opt_overlap_check_template, opt_overlap_check)) 1042 { 1043 error_setg(errp, "Conflicting values for qcow2 options '" 1044 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 1045 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 1046 ret = -EINVAL; 1047 goto fail; 1048 } 1049 if (!opt_overlap_check) { 1050 opt_overlap_check = opt_overlap_check_template ?: "cached"; 1051 } 1052 1053 if (!strcmp(opt_overlap_check, "none")) { 1054 overlap_check_template = 0; 1055 } else if (!strcmp(opt_overlap_check, "constant")) { 1056 overlap_check_template = QCOW2_OL_CONSTANT; 1057 } else if (!strcmp(opt_overlap_check, "cached")) { 1058 overlap_check_template = QCOW2_OL_CACHED; 1059 } else if (!strcmp(opt_overlap_check, "all")) { 1060 overlap_check_template = QCOW2_OL_ALL; 1061 } else { 1062 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1063 "'overlap-check'. Allowed are any of the following: " 1064 "none, constant, cached, all", opt_overlap_check); 1065 ret = -EINVAL; 1066 goto fail; 1067 } 1068 1069 r->overlap_check = 0; 1070 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1071 /* overlap-check defines a template bitmask, but every flag may be 1072 * overwritten through the associated boolean option */ 1073 r->overlap_check |= 1074 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1075 overlap_check_template & (1 << i)) << i; 1076 } 1077 1078 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 1079 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1080 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1081 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1082 flags & BDRV_O_UNMAP); 1083 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1084 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1085 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1086 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1087 1088 switch (s->crypt_method_header) { 1089 case QCOW_CRYPT_NONE: 1090 if (encryptfmt) { 1091 error_setg(errp, "No encryption in image header, but options " 1092 "specified format '%s'", encryptfmt); 1093 ret = -EINVAL; 1094 goto fail; 1095 } 1096 break; 1097 1098 case QCOW_CRYPT_AES: 1099 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1100 error_setg(errp, 1101 "Header reported 'aes' encryption format but " 1102 "options specify '%s'", encryptfmt); 1103 ret = -EINVAL; 1104 goto fail; 1105 } 1106 qdict_put_str(encryptopts, "format", "qcow"); 1107 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1108 break; 1109 1110 case QCOW_CRYPT_LUKS: 1111 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1112 error_setg(errp, 1113 "Header reported 'luks' encryption format but " 1114 "options specify '%s'", encryptfmt); 1115 ret = -EINVAL; 1116 goto fail; 1117 } 1118 qdict_put_str(encryptopts, "format", "luks"); 1119 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1120 break; 1121 1122 default: 1123 error_setg(errp, "Unsupported encryption method %d", 1124 s->crypt_method_header); 1125 break; 1126 } 1127 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1128 ret = -EINVAL; 1129 goto fail; 1130 } 1131 1132 ret = 0; 1133 fail: 1134 qobject_unref(encryptopts); 1135 qemu_opts_del(opts); 1136 opts = NULL; 1137 return ret; 1138 } 1139 1140 static void qcow2_update_options_commit(BlockDriverState *bs, 1141 Qcow2ReopenState *r) 1142 { 1143 BDRVQcow2State *s = bs->opaque; 1144 int i; 1145 1146 if (s->l2_table_cache) { 1147 qcow2_cache_destroy(s->l2_table_cache); 1148 } 1149 if (s->refcount_block_cache) { 1150 qcow2_cache_destroy(s->refcount_block_cache); 1151 } 1152 s->l2_table_cache = r->l2_table_cache; 1153 s->refcount_block_cache = r->refcount_block_cache; 1154 s->l2_slice_size = r->l2_slice_size; 1155 1156 s->overlap_check = r->overlap_check; 1157 s->use_lazy_refcounts = r->use_lazy_refcounts; 1158 1159 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1160 s->discard_passthrough[i] = r->discard_passthrough[i]; 1161 } 1162 1163 if (s->cache_clean_interval != r->cache_clean_interval) { 1164 cache_clean_timer_del(bs); 1165 s->cache_clean_interval = r->cache_clean_interval; 1166 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1167 } 1168 1169 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1170 s->crypto_opts = r->crypto_opts; 1171 } 1172 1173 static void qcow2_update_options_abort(BlockDriverState *bs, 1174 Qcow2ReopenState *r) 1175 { 1176 if (r->l2_table_cache) { 1177 qcow2_cache_destroy(r->l2_table_cache); 1178 } 1179 if (r->refcount_block_cache) { 1180 qcow2_cache_destroy(r->refcount_block_cache); 1181 } 1182 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1183 } 1184 1185 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1186 int flags, Error **errp) 1187 { 1188 Qcow2ReopenState r = {}; 1189 int ret; 1190 1191 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1192 if (ret >= 0) { 1193 qcow2_update_options_commit(bs, &r); 1194 } else { 1195 qcow2_update_options_abort(bs, &r); 1196 } 1197 1198 return ret; 1199 } 1200 1201 /* Called with s->lock held. */ 1202 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, 1203 int flags, Error **errp) 1204 { 1205 BDRVQcow2State *s = bs->opaque; 1206 unsigned int len, i; 1207 int ret = 0; 1208 QCowHeader header; 1209 Error *local_err = NULL; 1210 uint64_t ext_end; 1211 uint64_t l1_vm_state_index; 1212 bool update_header = false; 1213 1214 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1215 if (ret < 0) { 1216 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1217 goto fail; 1218 } 1219 header.magic = be32_to_cpu(header.magic); 1220 header.version = be32_to_cpu(header.version); 1221 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 1222 header.backing_file_size = be32_to_cpu(header.backing_file_size); 1223 header.size = be64_to_cpu(header.size); 1224 header.cluster_bits = be32_to_cpu(header.cluster_bits); 1225 header.crypt_method = be32_to_cpu(header.crypt_method); 1226 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 1227 header.l1_size = be32_to_cpu(header.l1_size); 1228 header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset); 1229 header.refcount_table_clusters = 1230 be32_to_cpu(header.refcount_table_clusters); 1231 header.snapshots_offset = be64_to_cpu(header.snapshots_offset); 1232 header.nb_snapshots = be32_to_cpu(header.nb_snapshots); 1233 1234 if (header.magic != QCOW_MAGIC) { 1235 error_setg(errp, "Image is not in qcow2 format"); 1236 ret = -EINVAL; 1237 goto fail; 1238 } 1239 if (header.version < 2 || header.version > 3) { 1240 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1241 ret = -ENOTSUP; 1242 goto fail; 1243 } 1244 1245 s->qcow_version = header.version; 1246 1247 /* Initialise cluster size */ 1248 if (header.cluster_bits < MIN_CLUSTER_BITS || 1249 header.cluster_bits > MAX_CLUSTER_BITS) { 1250 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1251 header.cluster_bits); 1252 ret = -EINVAL; 1253 goto fail; 1254 } 1255 1256 s->cluster_bits = header.cluster_bits; 1257 s->cluster_size = 1 << s->cluster_bits; 1258 1259 /* Initialise version 3 header fields */ 1260 if (header.version == 2) { 1261 header.incompatible_features = 0; 1262 header.compatible_features = 0; 1263 header.autoclear_features = 0; 1264 header.refcount_order = 4; 1265 header.header_length = 72; 1266 } else { 1267 header.incompatible_features = 1268 be64_to_cpu(header.incompatible_features); 1269 header.compatible_features = be64_to_cpu(header.compatible_features); 1270 header.autoclear_features = be64_to_cpu(header.autoclear_features); 1271 header.refcount_order = be32_to_cpu(header.refcount_order); 1272 header.header_length = be32_to_cpu(header.header_length); 1273 1274 if (header.header_length < 104) { 1275 error_setg(errp, "qcow2 header too short"); 1276 ret = -EINVAL; 1277 goto fail; 1278 } 1279 } 1280 1281 if (header.header_length > s->cluster_size) { 1282 error_setg(errp, "qcow2 header exceeds cluster size"); 1283 ret = -EINVAL; 1284 goto fail; 1285 } 1286 1287 if (header.header_length > sizeof(header)) { 1288 s->unknown_header_fields_size = header.header_length - sizeof(header); 1289 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1290 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1291 s->unknown_header_fields_size); 1292 if (ret < 0) { 1293 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1294 "fields"); 1295 goto fail; 1296 } 1297 } 1298 1299 if (header.backing_file_offset > s->cluster_size) { 1300 error_setg(errp, "Invalid backing file offset"); 1301 ret = -EINVAL; 1302 goto fail; 1303 } 1304 1305 if (header.backing_file_offset) { 1306 ext_end = header.backing_file_offset; 1307 } else { 1308 ext_end = 1 << header.cluster_bits; 1309 } 1310 1311 /* Handle feature bits */ 1312 s->incompatible_features = header.incompatible_features; 1313 s->compatible_features = header.compatible_features; 1314 s->autoclear_features = header.autoclear_features; 1315 1316 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1317 void *feature_table = NULL; 1318 qcow2_read_extensions(bs, header.header_length, ext_end, 1319 &feature_table, flags, NULL, NULL); 1320 report_unsupported_feature(errp, feature_table, 1321 s->incompatible_features & 1322 ~QCOW2_INCOMPAT_MASK); 1323 ret = -ENOTSUP; 1324 g_free(feature_table); 1325 goto fail; 1326 } 1327 1328 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1329 /* Corrupt images may not be written to unless they are being repaired 1330 */ 1331 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1332 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1333 "read/write"); 1334 ret = -EACCES; 1335 goto fail; 1336 } 1337 } 1338 1339 /* Check support for various header values */ 1340 if (header.refcount_order > 6) { 1341 error_setg(errp, "Reference count entry width too large; may not " 1342 "exceed 64 bits"); 1343 ret = -EINVAL; 1344 goto fail; 1345 } 1346 s->refcount_order = header.refcount_order; 1347 s->refcount_bits = 1 << s->refcount_order; 1348 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1349 s->refcount_max += s->refcount_max - 1; 1350 1351 s->crypt_method_header = header.crypt_method; 1352 if (s->crypt_method_header) { 1353 if (bdrv_uses_whitelist() && 1354 s->crypt_method_header == QCOW_CRYPT_AES) { 1355 error_setg(errp, 1356 "Use of AES-CBC encrypted qcow2 images is no longer " 1357 "supported in system emulators"); 1358 error_append_hint(errp, 1359 "You can use 'qemu-img convert' to convert your " 1360 "image to an alternative supported format, such " 1361 "as unencrypted qcow2, or raw with the LUKS " 1362 "format instead.\n"); 1363 ret = -ENOSYS; 1364 goto fail; 1365 } 1366 1367 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1368 s->crypt_physical_offset = false; 1369 } else { 1370 /* Assuming LUKS and any future crypt methods we 1371 * add will all use physical offsets, due to the 1372 * fact that the alternative is insecure... */ 1373 s->crypt_physical_offset = true; 1374 } 1375 1376 bs->encrypted = true; 1377 } 1378 1379 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1380 s->l2_size = 1 << s->l2_bits; 1381 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1382 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1383 s->refcount_block_size = 1 << s->refcount_block_bits; 1384 bs->total_sectors = header.size / BDRV_SECTOR_SIZE; 1385 s->csize_shift = (62 - (s->cluster_bits - 8)); 1386 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1387 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1388 1389 s->refcount_table_offset = header.refcount_table_offset; 1390 s->refcount_table_size = 1391 header.refcount_table_clusters << (s->cluster_bits - 3); 1392 1393 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1394 error_setg(errp, "Image does not contain a reference count table"); 1395 ret = -EINVAL; 1396 goto fail; 1397 } 1398 1399 ret = qcow2_validate_table(bs, s->refcount_table_offset, 1400 header.refcount_table_clusters, 1401 s->cluster_size, QCOW_MAX_REFTABLE_SIZE, 1402 "Reference count table", errp); 1403 if (ret < 0) { 1404 goto fail; 1405 } 1406 1407 /* The total size in bytes of the snapshot table is checked in 1408 * qcow2_read_snapshots() because the size of each snapshot is 1409 * variable and we don't know it yet. 1410 * Here we only check the offset and number of snapshots. */ 1411 ret = qcow2_validate_table(bs, header.snapshots_offset, 1412 header.nb_snapshots, 1413 sizeof(QCowSnapshotHeader), 1414 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, 1415 "Snapshot table", errp); 1416 if (ret < 0) { 1417 goto fail; 1418 } 1419 1420 /* read the level 1 table */ 1421 ret = qcow2_validate_table(bs, header.l1_table_offset, 1422 header.l1_size, sizeof(uint64_t), 1423 QCOW_MAX_L1_SIZE, "Active L1 table", errp); 1424 if (ret < 0) { 1425 goto fail; 1426 } 1427 s->l1_size = header.l1_size; 1428 s->l1_table_offset = header.l1_table_offset; 1429 1430 l1_vm_state_index = size_to_l1(s, header.size); 1431 if (l1_vm_state_index > INT_MAX) { 1432 error_setg(errp, "Image is too big"); 1433 ret = -EFBIG; 1434 goto fail; 1435 } 1436 s->l1_vm_state_index = l1_vm_state_index; 1437 1438 /* the L1 table must contain at least enough entries to put 1439 header.size bytes */ 1440 if (s->l1_size < s->l1_vm_state_index) { 1441 error_setg(errp, "L1 table is too small"); 1442 ret = -EINVAL; 1443 goto fail; 1444 } 1445 1446 if (s->l1_size > 0) { 1447 s->l1_table = qemu_try_blockalign(bs->file->bs, 1448 ROUND_UP(s->l1_size * sizeof(uint64_t), 512)); 1449 if (s->l1_table == NULL) { 1450 error_setg(errp, "Could not allocate L1 table"); 1451 ret = -ENOMEM; 1452 goto fail; 1453 } 1454 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1455 s->l1_size * sizeof(uint64_t)); 1456 if (ret < 0) { 1457 error_setg_errno(errp, -ret, "Could not read L1 table"); 1458 goto fail; 1459 } 1460 for(i = 0;i < s->l1_size; i++) { 1461 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 1462 } 1463 } 1464 1465 /* Parse driver-specific options */ 1466 ret = qcow2_update_options(bs, options, flags, errp); 1467 if (ret < 0) { 1468 goto fail; 1469 } 1470 1471 s->flags = flags; 1472 1473 ret = qcow2_refcount_init(bs); 1474 if (ret != 0) { 1475 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1476 goto fail; 1477 } 1478 1479 QLIST_INIT(&s->cluster_allocs); 1480 QTAILQ_INIT(&s->discards); 1481 1482 /* read qcow2 extensions */ 1483 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1484 flags, &update_header, &local_err)) { 1485 error_propagate(errp, local_err); 1486 ret = -EINVAL; 1487 goto fail; 1488 } 1489 1490 /* Open external data file */ 1491 s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file, 1492 true, &local_err); 1493 if (local_err) { 1494 error_propagate(errp, local_err); 1495 ret = -EINVAL; 1496 goto fail; 1497 } 1498 1499 if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { 1500 if (!s->data_file && s->image_data_file) { 1501 s->data_file = bdrv_open_child(s->image_data_file, options, 1502 "data-file", bs, &child_file, 1503 false, errp); 1504 if (!s->data_file) { 1505 ret = -EINVAL; 1506 goto fail; 1507 } 1508 } 1509 if (!s->data_file) { 1510 error_setg(errp, "'data-file' is required for this image"); 1511 ret = -EINVAL; 1512 goto fail; 1513 } 1514 } else { 1515 if (s->data_file) { 1516 error_setg(errp, "'data-file' can only be set for images with an " 1517 "external data file"); 1518 ret = -EINVAL; 1519 goto fail; 1520 } 1521 1522 s->data_file = bs->file; 1523 1524 if (data_file_is_raw(bs)) { 1525 error_setg(errp, "data-file-raw requires a data file"); 1526 ret = -EINVAL; 1527 goto fail; 1528 } 1529 } 1530 1531 /* qcow2_read_extension may have set up the crypto context 1532 * if the crypt method needs a header region, some methods 1533 * don't need header extensions, so must check here 1534 */ 1535 if (s->crypt_method_header && !s->crypto) { 1536 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1537 unsigned int cflags = 0; 1538 if (flags & BDRV_O_NO_IO) { 1539 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1540 } 1541 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1542 NULL, NULL, cflags, 1543 QCOW2_MAX_THREADS, errp); 1544 if (!s->crypto) { 1545 ret = -EINVAL; 1546 goto fail; 1547 } 1548 } else if (!(flags & BDRV_O_NO_IO)) { 1549 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1550 s->crypt_method_header); 1551 ret = -EINVAL; 1552 goto fail; 1553 } 1554 } 1555 1556 /* read the backing file name */ 1557 if (header.backing_file_offset != 0) { 1558 len = header.backing_file_size; 1559 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1560 len >= sizeof(bs->backing_file)) { 1561 error_setg(errp, "Backing file name too long"); 1562 ret = -EINVAL; 1563 goto fail; 1564 } 1565 ret = bdrv_pread(bs->file, header.backing_file_offset, 1566 bs->auto_backing_file, len); 1567 if (ret < 0) { 1568 error_setg_errno(errp, -ret, "Could not read backing file name"); 1569 goto fail; 1570 } 1571 bs->auto_backing_file[len] = '\0'; 1572 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1573 bs->auto_backing_file); 1574 s->image_backing_file = g_strdup(bs->auto_backing_file); 1575 } 1576 1577 /* Internal snapshots */ 1578 s->snapshots_offset = header.snapshots_offset; 1579 s->nb_snapshots = header.nb_snapshots; 1580 1581 ret = qcow2_read_snapshots(bs); 1582 if (ret < 0) { 1583 error_setg_errno(errp, -ret, "Could not read snapshots"); 1584 goto fail; 1585 } 1586 1587 /* Clear unknown autoclear feature bits */ 1588 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1589 update_header = 1590 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1591 if (update_header) { 1592 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1593 } 1594 1595 /* == Handle persistent dirty bitmaps == 1596 * 1597 * We want load dirty bitmaps in three cases: 1598 * 1599 * 1. Normal open of the disk in active mode, not related to invalidation 1600 * after migration. 1601 * 1602 * 2. Invalidation of the target vm after pre-copy phase of migration, if 1603 * bitmaps are _not_ migrating through migration channel, i.e. 1604 * 'dirty-bitmaps' capability is disabled. 1605 * 1606 * 3. Invalidation of source vm after failed or canceled migration. 1607 * This is a very interesting case. There are two possible types of 1608 * bitmaps: 1609 * 1610 * A. Stored on inactivation and removed. They should be loaded from the 1611 * image. 1612 * 1613 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through 1614 * the migration channel (with dirty-bitmaps capability). 1615 * 1616 * On the other hand, there are two possible sub-cases: 1617 * 1618 * 3.1 disk was changed by somebody else while were inactive. In this 1619 * case all in-RAM dirty bitmaps (both persistent and not) are 1620 * definitely invalid. And we don't have any method to determine 1621 * this. 1622 * 1623 * Simple and safe thing is to just drop all the bitmaps of type B on 1624 * inactivation. But in this case we lose bitmaps in valid 4.2 case. 1625 * 1626 * On the other hand, resuming source vm, if disk was already changed 1627 * is a bad thing anyway: not only bitmaps, the whole vm state is 1628 * out of sync with disk. 1629 * 1630 * This means, that user or management tool, who for some reason 1631 * decided to resume source vm, after disk was already changed by 1632 * target vm, should at least drop all dirty bitmaps by hand. 1633 * 1634 * So, we can ignore this case for now, but TODO: "generation" 1635 * extension for qcow2, to determine, that image was changed after 1636 * last inactivation. And if it is changed, we will drop (or at least 1637 * mark as 'invalid' all the bitmaps of type B, both persistent 1638 * and not). 1639 * 1640 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved 1641 * to disk ('dirty-bitmaps' capability disabled), or not saved 1642 * ('dirty-bitmaps' capability enabled), but we don't need to care 1643 * of: let's load bitmaps as always: stored bitmaps will be loaded, 1644 * and not stored has flag IN_USE=1 in the image and will be skipped 1645 * on loading. 1646 * 1647 * One remaining possible case when we don't want load bitmaps: 1648 * 1649 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or 1650 * will be loaded on invalidation, no needs try loading them before) 1651 */ 1652 1653 if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { 1654 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ 1655 bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); 1656 1657 update_header = update_header && !header_updated; 1658 } 1659 if (local_err != NULL) { 1660 error_propagate(errp, local_err); 1661 ret = -EINVAL; 1662 goto fail; 1663 } 1664 1665 if (update_header) { 1666 ret = qcow2_update_header(bs); 1667 if (ret < 0) { 1668 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1669 goto fail; 1670 } 1671 } 1672 1673 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1674 1675 /* Repair image if dirty */ 1676 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1677 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1678 BdrvCheckResult result = {0}; 1679 1680 ret = qcow2_co_check_locked(bs, &result, 1681 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1682 if (ret < 0 || result.check_errors) { 1683 if (ret >= 0) { 1684 ret = -EIO; 1685 } 1686 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1687 goto fail; 1688 } 1689 } 1690 1691 #ifdef DEBUG_ALLOC 1692 { 1693 BdrvCheckResult result = {0}; 1694 qcow2_check_refcounts(bs, &result, 0); 1695 } 1696 #endif 1697 1698 qemu_co_queue_init(&s->thread_task_queue); 1699 1700 return ret; 1701 1702 fail: 1703 g_free(s->image_data_file); 1704 if (has_data_file(bs)) { 1705 bdrv_unref_child(bs, s->data_file); 1706 } 1707 g_free(s->unknown_header_fields); 1708 cleanup_unknown_header_ext(bs); 1709 qcow2_free_snapshots(bs); 1710 qcow2_refcount_close(bs); 1711 qemu_vfree(s->l1_table); 1712 /* else pre-write overlap checks in cache_destroy may crash */ 1713 s->l1_table = NULL; 1714 cache_clean_timer_del(bs); 1715 if (s->l2_table_cache) { 1716 qcow2_cache_destroy(s->l2_table_cache); 1717 } 1718 if (s->refcount_block_cache) { 1719 qcow2_cache_destroy(s->refcount_block_cache); 1720 } 1721 qcrypto_block_free(s->crypto); 1722 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1723 return ret; 1724 } 1725 1726 typedef struct QCow2OpenCo { 1727 BlockDriverState *bs; 1728 QDict *options; 1729 int flags; 1730 Error **errp; 1731 int ret; 1732 } QCow2OpenCo; 1733 1734 static void coroutine_fn qcow2_open_entry(void *opaque) 1735 { 1736 QCow2OpenCo *qoc = opaque; 1737 BDRVQcow2State *s = qoc->bs->opaque; 1738 1739 qemu_co_mutex_lock(&s->lock); 1740 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); 1741 qemu_co_mutex_unlock(&s->lock); 1742 } 1743 1744 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1745 Error **errp) 1746 { 1747 BDRVQcow2State *s = bs->opaque; 1748 QCow2OpenCo qoc = { 1749 .bs = bs, 1750 .options = options, 1751 .flags = flags, 1752 .errp = errp, 1753 .ret = -EINPROGRESS 1754 }; 1755 1756 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1757 false, errp); 1758 if (!bs->file) { 1759 return -EINVAL; 1760 } 1761 1762 /* Initialise locks */ 1763 qemu_co_mutex_init(&s->lock); 1764 1765 if (qemu_in_coroutine()) { 1766 /* From bdrv_co_create. */ 1767 qcow2_open_entry(&qoc); 1768 } else { 1769 assert(qemu_get_current_aio_context() == qemu_get_aio_context()); 1770 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); 1771 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); 1772 } 1773 return qoc.ret; 1774 } 1775 1776 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1777 { 1778 BDRVQcow2State *s = bs->opaque; 1779 1780 if (bs->encrypted) { 1781 /* Encryption works on a sector granularity */ 1782 bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto); 1783 } 1784 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1785 bs->bl.pdiscard_alignment = s->cluster_size; 1786 } 1787 1788 static int qcow2_reopen_prepare(BDRVReopenState *state, 1789 BlockReopenQueue *queue, Error **errp) 1790 { 1791 Qcow2ReopenState *r; 1792 int ret; 1793 1794 r = g_new0(Qcow2ReopenState, 1); 1795 state->opaque = r; 1796 1797 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1798 state->flags, errp); 1799 if (ret < 0) { 1800 goto fail; 1801 } 1802 1803 /* We need to write out any unwritten data if we reopen read-only. */ 1804 if ((state->flags & BDRV_O_RDWR) == 0) { 1805 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1806 if (ret < 0) { 1807 goto fail; 1808 } 1809 1810 ret = bdrv_flush(state->bs); 1811 if (ret < 0) { 1812 goto fail; 1813 } 1814 1815 ret = qcow2_mark_clean(state->bs); 1816 if (ret < 0) { 1817 goto fail; 1818 } 1819 } 1820 1821 return 0; 1822 1823 fail: 1824 qcow2_update_options_abort(state->bs, r); 1825 g_free(r); 1826 return ret; 1827 } 1828 1829 static void qcow2_reopen_commit(BDRVReopenState *state) 1830 { 1831 qcow2_update_options_commit(state->bs, state->opaque); 1832 g_free(state->opaque); 1833 } 1834 1835 static void qcow2_reopen_abort(BDRVReopenState *state) 1836 { 1837 qcow2_update_options_abort(state->bs, state->opaque); 1838 g_free(state->opaque); 1839 } 1840 1841 static void qcow2_join_options(QDict *options, QDict *old_options) 1842 { 1843 bool has_new_overlap_template = 1844 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1845 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1846 bool has_new_total_cache_size = 1847 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1848 bool has_all_cache_options; 1849 1850 /* New overlap template overrides all old overlap options */ 1851 if (has_new_overlap_template) { 1852 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1853 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1854 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1855 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1856 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1857 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1858 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1859 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1860 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1861 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1862 } 1863 1864 /* New total cache size overrides all old options */ 1865 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1866 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1867 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1868 } 1869 1870 qdict_join(options, old_options, false); 1871 1872 /* 1873 * If after merging all cache size options are set, an old total size is 1874 * overwritten. Do keep all options, however, if all three are new. The 1875 * resulting error message is what we want to happen. 1876 */ 1877 has_all_cache_options = 1878 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1879 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1880 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1881 1882 if (has_all_cache_options && !has_new_total_cache_size) { 1883 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1884 } 1885 } 1886 1887 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, 1888 bool want_zero, 1889 int64_t offset, int64_t count, 1890 int64_t *pnum, int64_t *map, 1891 BlockDriverState **file) 1892 { 1893 BDRVQcow2State *s = bs->opaque; 1894 uint64_t cluster_offset; 1895 int index_in_cluster, ret; 1896 unsigned int bytes; 1897 int status = 0; 1898 1899 if (!s->metadata_preallocation_checked) { 1900 ret = qcow2_detect_metadata_preallocation(bs); 1901 s->metadata_preallocation = (ret == 1); 1902 s->metadata_preallocation_checked = true; 1903 } 1904 1905 bytes = MIN(INT_MAX, count); 1906 qemu_co_mutex_lock(&s->lock); 1907 ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); 1908 qemu_co_mutex_unlock(&s->lock); 1909 if (ret < 0) { 1910 return ret; 1911 } 1912 1913 *pnum = bytes; 1914 1915 if ((ret == QCOW2_CLUSTER_NORMAL || ret == QCOW2_CLUSTER_ZERO_ALLOC) && 1916 !s->crypto) { 1917 index_in_cluster = offset & (s->cluster_size - 1); 1918 *map = cluster_offset | index_in_cluster; 1919 *file = s->data_file->bs; 1920 status |= BDRV_BLOCK_OFFSET_VALID; 1921 } 1922 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1923 status |= BDRV_BLOCK_ZERO; 1924 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1925 status |= BDRV_BLOCK_DATA; 1926 } 1927 if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) && 1928 (status & BDRV_BLOCK_OFFSET_VALID)) 1929 { 1930 status |= BDRV_BLOCK_RECURSE; 1931 } 1932 return status; 1933 } 1934 1935 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, 1936 QCowL2Meta **pl2meta, 1937 bool link_l2) 1938 { 1939 int ret = 0; 1940 QCowL2Meta *l2meta = *pl2meta; 1941 1942 while (l2meta != NULL) { 1943 QCowL2Meta *next; 1944 1945 if (link_l2) { 1946 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1947 if (ret) { 1948 goto out; 1949 } 1950 } else { 1951 qcow2_alloc_cluster_abort(bs, l2meta); 1952 } 1953 1954 /* Take the request off the list of running requests */ 1955 if (l2meta->nb_clusters != 0) { 1956 QLIST_REMOVE(l2meta, next_in_flight); 1957 } 1958 1959 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1960 1961 next = l2meta->next; 1962 g_free(l2meta); 1963 l2meta = next; 1964 } 1965 out: 1966 *pl2meta = l2meta; 1967 return ret; 1968 } 1969 1970 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1971 uint64_t bytes, QEMUIOVector *qiov, 1972 int flags) 1973 { 1974 BDRVQcow2State *s = bs->opaque; 1975 int offset_in_cluster; 1976 int ret; 1977 unsigned int cur_bytes; /* number of bytes in current iteration */ 1978 uint64_t cluster_offset = 0; 1979 uint64_t bytes_done = 0; 1980 QEMUIOVector hd_qiov; 1981 uint8_t *cluster_data = NULL; 1982 1983 qemu_iovec_init(&hd_qiov, qiov->niov); 1984 1985 while (bytes != 0) { 1986 1987 /* prepare next request */ 1988 cur_bytes = MIN(bytes, INT_MAX); 1989 if (s->crypto) { 1990 cur_bytes = MIN(cur_bytes, 1991 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1992 } 1993 1994 qemu_co_mutex_lock(&s->lock); 1995 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1996 qemu_co_mutex_unlock(&s->lock); 1997 if (ret < 0) { 1998 goto fail; 1999 } 2000 2001 offset_in_cluster = offset_into_cluster(s, offset); 2002 2003 qemu_iovec_reset(&hd_qiov); 2004 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 2005 2006 switch (ret) { 2007 case QCOW2_CLUSTER_UNALLOCATED: 2008 2009 if (bs->backing) { 2010 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 2011 ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, 2012 &hd_qiov, 0); 2013 if (ret < 0) { 2014 goto fail; 2015 } 2016 } else { 2017 /* Note: in this case, no need to wait */ 2018 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 2019 } 2020 break; 2021 2022 case QCOW2_CLUSTER_ZERO_PLAIN: 2023 case QCOW2_CLUSTER_ZERO_ALLOC: 2024 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 2025 break; 2026 2027 case QCOW2_CLUSTER_COMPRESSED: 2028 ret = qcow2_co_preadv_compressed(bs, cluster_offset, 2029 offset, cur_bytes, 2030 &hd_qiov); 2031 if (ret < 0) { 2032 goto fail; 2033 } 2034 2035 break; 2036 2037 case QCOW2_CLUSTER_NORMAL: 2038 if ((cluster_offset & 511) != 0) { 2039 ret = -EIO; 2040 goto fail; 2041 } 2042 2043 if (bs->encrypted) { 2044 assert(s->crypto); 2045 2046 /* 2047 * For encrypted images, read everything into a temporary 2048 * contiguous buffer on which the AES functions can work. 2049 */ 2050 if (!cluster_data) { 2051 cluster_data = 2052 qemu_try_blockalign(s->data_file->bs, 2053 QCOW_MAX_CRYPT_CLUSTERS 2054 * s->cluster_size); 2055 if (cluster_data == NULL) { 2056 ret = -ENOMEM; 2057 goto fail; 2058 } 2059 } 2060 2061 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2062 qemu_iovec_reset(&hd_qiov); 2063 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 2064 } 2065 2066 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 2067 ret = bdrv_co_preadv(s->data_file, 2068 cluster_offset + offset_in_cluster, 2069 cur_bytes, &hd_qiov, 0); 2070 if (ret < 0) { 2071 goto fail; 2072 } 2073 if (bs->encrypted) { 2074 assert(s->crypto); 2075 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 2076 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 2077 if (qcow2_co_decrypt(bs, cluster_offset, offset, 2078 cluster_data, cur_bytes) < 0) { 2079 ret = -EIO; 2080 goto fail; 2081 } 2082 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 2083 } 2084 break; 2085 2086 default: 2087 g_assert_not_reached(); 2088 ret = -EIO; 2089 goto fail; 2090 } 2091 2092 bytes -= cur_bytes; 2093 offset += cur_bytes; 2094 bytes_done += cur_bytes; 2095 } 2096 ret = 0; 2097 2098 fail: 2099 qemu_iovec_destroy(&hd_qiov); 2100 qemu_vfree(cluster_data); 2101 2102 return ret; 2103 } 2104 2105 /* Check if it's possible to merge a write request with the writing of 2106 * the data from the COW regions */ 2107 static bool merge_cow(uint64_t offset, unsigned bytes, 2108 QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) 2109 { 2110 QCowL2Meta *m; 2111 2112 for (m = l2meta; m != NULL; m = m->next) { 2113 /* If both COW regions are empty then there's nothing to merge */ 2114 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 2115 continue; 2116 } 2117 2118 /* If COW regions are handled already, skip this too */ 2119 if (m->skip_cow) { 2120 continue; 2121 } 2122 2123 /* The data (middle) region must be immediately after the 2124 * start region */ 2125 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 2126 continue; 2127 } 2128 2129 /* The end region must be immediately after the data (middle) 2130 * region */ 2131 if (m->offset + m->cow_end.offset != offset + bytes) { 2132 continue; 2133 } 2134 2135 /* Make sure that adding both COW regions to the QEMUIOVector 2136 * does not exceed IOV_MAX */ 2137 if (hd_qiov->niov > IOV_MAX - 2) { 2138 continue; 2139 } 2140 2141 m->data_qiov = hd_qiov; 2142 return true; 2143 } 2144 2145 return false; 2146 } 2147 2148 static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes) 2149 { 2150 int64_t nr; 2151 return !bytes || 2152 (!bdrv_is_allocated_above(bs, NULL, false, offset, bytes, &nr) && 2153 nr == bytes); 2154 } 2155 2156 static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m) 2157 { 2158 /* 2159 * This check is designed for optimization shortcut so it must be 2160 * efficient. 2161 * Instead of is_zero(), use is_unallocated() as it is faster (but not 2162 * as accurate and can result in false negatives). 2163 */ 2164 return is_unallocated(bs, m->offset + m->cow_start.offset, 2165 m->cow_start.nb_bytes) && 2166 is_unallocated(bs, m->offset + m->cow_end.offset, 2167 m->cow_end.nb_bytes); 2168 } 2169 2170 static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) 2171 { 2172 BDRVQcow2State *s = bs->opaque; 2173 QCowL2Meta *m; 2174 2175 if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) { 2176 return 0; 2177 } 2178 2179 if (bs->encrypted) { 2180 return 0; 2181 } 2182 2183 for (m = l2meta; m != NULL; m = m->next) { 2184 int ret; 2185 2186 if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) { 2187 continue; 2188 } 2189 2190 if (!is_zero_cow(bs, m)) { 2191 continue; 2192 } 2193 2194 /* 2195 * instead of writing zero COW buffers, 2196 * efficiently zero out the whole clusters 2197 */ 2198 2199 ret = qcow2_pre_write_overlap_check(bs, 0, m->alloc_offset, 2200 m->nb_clusters * s->cluster_size, 2201 true); 2202 if (ret < 0) { 2203 return ret; 2204 } 2205 2206 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE); 2207 ret = bdrv_co_pwrite_zeroes(s->data_file, m->alloc_offset, 2208 m->nb_clusters * s->cluster_size, 2209 BDRV_REQ_NO_FALLBACK); 2210 if (ret < 0) { 2211 if (ret != -ENOTSUP && ret != -EAGAIN) { 2212 return ret; 2213 } 2214 continue; 2215 } 2216 2217 trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters); 2218 m->skip_cow = true; 2219 } 2220 return 0; 2221 } 2222 2223 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 2224 uint64_t bytes, QEMUIOVector *qiov, 2225 int flags) 2226 { 2227 BDRVQcow2State *s = bs->opaque; 2228 int offset_in_cluster; 2229 int ret; 2230 unsigned int cur_bytes; /* number of sectors in current iteration */ 2231 uint64_t cluster_offset; 2232 QEMUIOVector hd_qiov; 2233 uint64_t bytes_done = 0; 2234 uint8_t *cluster_data = NULL; 2235 QCowL2Meta *l2meta = NULL; 2236 2237 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 2238 2239 qemu_iovec_init(&hd_qiov, qiov->niov); 2240 2241 qemu_co_mutex_lock(&s->lock); 2242 2243 while (bytes != 0) { 2244 2245 l2meta = NULL; 2246 2247 trace_qcow2_writev_start_part(qemu_coroutine_self()); 2248 offset_in_cluster = offset_into_cluster(s, offset); 2249 cur_bytes = MIN(bytes, INT_MAX); 2250 if (bs->encrypted) { 2251 cur_bytes = MIN(cur_bytes, 2252 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 2253 - offset_in_cluster); 2254 } 2255 2256 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2257 &cluster_offset, &l2meta); 2258 if (ret < 0) { 2259 goto out_locked; 2260 } 2261 2262 assert((cluster_offset & 511) == 0); 2263 2264 ret = qcow2_pre_write_overlap_check(bs, 0, 2265 cluster_offset + offset_in_cluster, 2266 cur_bytes, true); 2267 if (ret < 0) { 2268 goto out_locked; 2269 } 2270 2271 qemu_co_mutex_unlock(&s->lock); 2272 2273 qemu_iovec_reset(&hd_qiov); 2274 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 2275 2276 if (bs->encrypted) { 2277 assert(s->crypto); 2278 if (!cluster_data) { 2279 cluster_data = qemu_try_blockalign(bs->file->bs, 2280 QCOW_MAX_CRYPT_CLUSTERS 2281 * s->cluster_size); 2282 if (cluster_data == NULL) { 2283 ret = -ENOMEM; 2284 goto out_unlocked; 2285 } 2286 } 2287 2288 assert(hd_qiov.size <= 2289 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2290 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 2291 2292 if (qcow2_co_encrypt(bs, cluster_offset, offset, 2293 cluster_data, cur_bytes) < 0) { 2294 ret = -EIO; 2295 goto out_unlocked; 2296 } 2297 2298 qemu_iovec_reset(&hd_qiov); 2299 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 2300 } 2301 2302 /* Try to efficiently initialize the physical space with zeroes */ 2303 ret = handle_alloc_space(bs, l2meta); 2304 if (ret < 0) { 2305 goto out_unlocked; 2306 } 2307 2308 /* If we need to do COW, check if it's possible to merge the 2309 * writing of the guest data together with that of the COW regions. 2310 * If it's not possible (or not necessary) then write the 2311 * guest data now. */ 2312 if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { 2313 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 2314 trace_qcow2_writev_data(qemu_coroutine_self(), 2315 cluster_offset + offset_in_cluster); 2316 ret = bdrv_co_pwritev(s->data_file, 2317 cluster_offset + offset_in_cluster, 2318 cur_bytes, &hd_qiov, 0); 2319 if (ret < 0) { 2320 goto out_unlocked; 2321 } 2322 } 2323 2324 qemu_co_mutex_lock(&s->lock); 2325 2326 ret = qcow2_handle_l2meta(bs, &l2meta, true); 2327 if (ret) { 2328 goto out_locked; 2329 } 2330 2331 bytes -= cur_bytes; 2332 offset += cur_bytes; 2333 bytes_done += cur_bytes; 2334 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2335 } 2336 ret = 0; 2337 goto out_locked; 2338 2339 out_unlocked: 2340 qemu_co_mutex_lock(&s->lock); 2341 2342 out_locked: 2343 qcow2_handle_l2meta(bs, &l2meta, false); 2344 2345 qemu_co_mutex_unlock(&s->lock); 2346 2347 qemu_iovec_destroy(&hd_qiov); 2348 qemu_vfree(cluster_data); 2349 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2350 2351 return ret; 2352 } 2353 2354 static int qcow2_inactivate(BlockDriverState *bs) 2355 { 2356 BDRVQcow2State *s = bs->opaque; 2357 int ret, result = 0; 2358 Error *local_err = NULL; 2359 2360 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2361 if (local_err != NULL) { 2362 result = -EINVAL; 2363 error_reportf_err(local_err, "Lost persistent bitmaps during " 2364 "inactivation of node '%s': ", 2365 bdrv_get_device_or_node_name(bs)); 2366 } 2367 2368 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2369 if (ret) { 2370 result = ret; 2371 error_report("Failed to flush the L2 table cache: %s", 2372 strerror(-ret)); 2373 } 2374 2375 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2376 if (ret) { 2377 result = ret; 2378 error_report("Failed to flush the refcount block cache: %s", 2379 strerror(-ret)); 2380 } 2381 2382 if (result == 0) { 2383 qcow2_mark_clean(bs); 2384 } 2385 2386 return result; 2387 } 2388 2389 static void qcow2_close(BlockDriverState *bs) 2390 { 2391 BDRVQcow2State *s = bs->opaque; 2392 qemu_vfree(s->l1_table); 2393 /* else pre-write overlap checks in cache_destroy may crash */ 2394 s->l1_table = NULL; 2395 2396 if (!(s->flags & BDRV_O_INACTIVE)) { 2397 qcow2_inactivate(bs); 2398 } 2399 2400 cache_clean_timer_del(bs); 2401 qcow2_cache_destroy(s->l2_table_cache); 2402 qcow2_cache_destroy(s->refcount_block_cache); 2403 2404 qcrypto_block_free(s->crypto); 2405 s->crypto = NULL; 2406 2407 g_free(s->unknown_header_fields); 2408 cleanup_unknown_header_ext(bs); 2409 2410 g_free(s->image_data_file); 2411 g_free(s->image_backing_file); 2412 g_free(s->image_backing_format); 2413 2414 if (has_data_file(bs)) { 2415 bdrv_unref_child(bs, s->data_file); 2416 } 2417 2418 qcow2_refcount_close(bs); 2419 qcow2_free_snapshots(bs); 2420 } 2421 2422 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, 2423 Error **errp) 2424 { 2425 BDRVQcow2State *s = bs->opaque; 2426 int flags = s->flags; 2427 QCryptoBlock *crypto = NULL; 2428 QDict *options; 2429 Error *local_err = NULL; 2430 int ret; 2431 2432 /* 2433 * Backing files are read-only which makes all of their metadata immutable, 2434 * that means we don't have to worry about reopening them here. 2435 */ 2436 2437 crypto = s->crypto; 2438 s->crypto = NULL; 2439 2440 qcow2_close(bs); 2441 2442 memset(s, 0, sizeof(BDRVQcow2State)); 2443 options = qdict_clone_shallow(bs->options); 2444 2445 flags &= ~BDRV_O_INACTIVE; 2446 qemu_co_mutex_lock(&s->lock); 2447 ret = qcow2_do_open(bs, options, flags, &local_err); 2448 qemu_co_mutex_unlock(&s->lock); 2449 qobject_unref(options); 2450 if (local_err) { 2451 error_propagate_prepend(errp, local_err, 2452 "Could not reopen qcow2 layer: "); 2453 bs->drv = NULL; 2454 return; 2455 } else if (ret < 0) { 2456 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2457 bs->drv = NULL; 2458 return; 2459 } 2460 2461 s->crypto = crypto; 2462 } 2463 2464 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2465 size_t len, size_t buflen) 2466 { 2467 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2468 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2469 2470 if (buflen < ext_len) { 2471 return -ENOSPC; 2472 } 2473 2474 *ext_backing_fmt = (QCowExtension) { 2475 .magic = cpu_to_be32(magic), 2476 .len = cpu_to_be32(len), 2477 }; 2478 2479 if (len) { 2480 memcpy(buf + sizeof(QCowExtension), s, len); 2481 } 2482 2483 return ext_len; 2484 } 2485 2486 /* 2487 * Updates the qcow2 header, including the variable length parts of it, i.e. 2488 * the backing file name and all extensions. qcow2 was not designed to allow 2489 * such changes, so if we run out of space (we can only use the first cluster) 2490 * this function may fail. 2491 * 2492 * Returns 0 on success, -errno in error cases. 2493 */ 2494 int qcow2_update_header(BlockDriverState *bs) 2495 { 2496 BDRVQcow2State *s = bs->opaque; 2497 QCowHeader *header; 2498 char *buf; 2499 size_t buflen = s->cluster_size; 2500 int ret; 2501 uint64_t total_size; 2502 uint32_t refcount_table_clusters; 2503 size_t header_length; 2504 Qcow2UnknownHeaderExtension *uext; 2505 2506 buf = qemu_blockalign(bs, buflen); 2507 2508 /* Header structure */ 2509 header = (QCowHeader*) buf; 2510 2511 if (buflen < sizeof(*header)) { 2512 ret = -ENOSPC; 2513 goto fail; 2514 } 2515 2516 header_length = sizeof(*header) + s->unknown_header_fields_size; 2517 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2518 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2519 2520 *header = (QCowHeader) { 2521 /* Version 2 fields */ 2522 .magic = cpu_to_be32(QCOW_MAGIC), 2523 .version = cpu_to_be32(s->qcow_version), 2524 .backing_file_offset = 0, 2525 .backing_file_size = 0, 2526 .cluster_bits = cpu_to_be32(s->cluster_bits), 2527 .size = cpu_to_be64(total_size), 2528 .crypt_method = cpu_to_be32(s->crypt_method_header), 2529 .l1_size = cpu_to_be32(s->l1_size), 2530 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2531 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2532 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2533 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2534 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2535 2536 /* Version 3 fields */ 2537 .incompatible_features = cpu_to_be64(s->incompatible_features), 2538 .compatible_features = cpu_to_be64(s->compatible_features), 2539 .autoclear_features = cpu_to_be64(s->autoclear_features), 2540 .refcount_order = cpu_to_be32(s->refcount_order), 2541 .header_length = cpu_to_be32(header_length), 2542 }; 2543 2544 /* For older versions, write a shorter header */ 2545 switch (s->qcow_version) { 2546 case 2: 2547 ret = offsetof(QCowHeader, incompatible_features); 2548 break; 2549 case 3: 2550 ret = sizeof(*header); 2551 break; 2552 default: 2553 ret = -EINVAL; 2554 goto fail; 2555 } 2556 2557 buf += ret; 2558 buflen -= ret; 2559 memset(buf, 0, buflen); 2560 2561 /* Preserve any unknown field in the header */ 2562 if (s->unknown_header_fields_size) { 2563 if (buflen < s->unknown_header_fields_size) { 2564 ret = -ENOSPC; 2565 goto fail; 2566 } 2567 2568 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2569 buf += s->unknown_header_fields_size; 2570 buflen -= s->unknown_header_fields_size; 2571 } 2572 2573 /* Backing file format header extension */ 2574 if (s->image_backing_format) { 2575 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2576 s->image_backing_format, 2577 strlen(s->image_backing_format), 2578 buflen); 2579 if (ret < 0) { 2580 goto fail; 2581 } 2582 2583 buf += ret; 2584 buflen -= ret; 2585 } 2586 2587 /* External data file header extension */ 2588 if (has_data_file(bs) && s->image_data_file) { 2589 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE, 2590 s->image_data_file, strlen(s->image_data_file), 2591 buflen); 2592 if (ret < 0) { 2593 goto fail; 2594 } 2595 2596 buf += ret; 2597 buflen -= ret; 2598 } 2599 2600 /* Full disk encryption header pointer extension */ 2601 if (s->crypto_header.offset != 0) { 2602 s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset); 2603 s->crypto_header.length = cpu_to_be64(s->crypto_header.length); 2604 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2605 &s->crypto_header, sizeof(s->crypto_header), 2606 buflen); 2607 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 2608 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 2609 if (ret < 0) { 2610 goto fail; 2611 } 2612 buf += ret; 2613 buflen -= ret; 2614 } 2615 2616 /* Feature table */ 2617 if (s->qcow_version >= 3) { 2618 Qcow2Feature features[] = { 2619 { 2620 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2621 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2622 .name = "dirty bit", 2623 }, 2624 { 2625 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2626 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2627 .name = "corrupt bit", 2628 }, 2629 { 2630 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2631 .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR, 2632 .name = "external data file", 2633 }, 2634 { 2635 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2636 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2637 .name = "lazy refcounts", 2638 }, 2639 }; 2640 2641 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2642 features, sizeof(features), buflen); 2643 if (ret < 0) { 2644 goto fail; 2645 } 2646 buf += ret; 2647 buflen -= ret; 2648 } 2649 2650 /* Bitmap extension */ 2651 if (s->nb_bitmaps > 0) { 2652 Qcow2BitmapHeaderExt bitmaps_header = { 2653 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2654 .bitmap_directory_size = 2655 cpu_to_be64(s->bitmap_directory_size), 2656 .bitmap_directory_offset = 2657 cpu_to_be64(s->bitmap_directory_offset) 2658 }; 2659 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2660 &bitmaps_header, sizeof(bitmaps_header), 2661 buflen); 2662 if (ret < 0) { 2663 goto fail; 2664 } 2665 buf += ret; 2666 buflen -= ret; 2667 } 2668 2669 /* Keep unknown header extensions */ 2670 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2671 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2672 if (ret < 0) { 2673 goto fail; 2674 } 2675 2676 buf += ret; 2677 buflen -= ret; 2678 } 2679 2680 /* End of header extensions */ 2681 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2682 if (ret < 0) { 2683 goto fail; 2684 } 2685 2686 buf += ret; 2687 buflen -= ret; 2688 2689 /* Backing file name */ 2690 if (s->image_backing_file) { 2691 size_t backing_file_len = strlen(s->image_backing_file); 2692 2693 if (buflen < backing_file_len) { 2694 ret = -ENOSPC; 2695 goto fail; 2696 } 2697 2698 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2699 strncpy(buf, s->image_backing_file, buflen); 2700 2701 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2702 header->backing_file_size = cpu_to_be32(backing_file_len); 2703 } 2704 2705 /* Write the new header */ 2706 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2707 if (ret < 0) { 2708 goto fail; 2709 } 2710 2711 ret = 0; 2712 fail: 2713 qemu_vfree(header); 2714 return ret; 2715 } 2716 2717 static int qcow2_change_backing_file(BlockDriverState *bs, 2718 const char *backing_file, const char *backing_fmt) 2719 { 2720 BDRVQcow2State *s = bs->opaque; 2721 2722 /* Adding a backing file means that the external data file alone won't be 2723 * enough to make sense of the content */ 2724 if (backing_file && data_file_is_raw(bs)) { 2725 return -EINVAL; 2726 } 2727 2728 if (backing_file && strlen(backing_file) > 1023) { 2729 return -EINVAL; 2730 } 2731 2732 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), 2733 backing_file ?: ""); 2734 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2735 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2736 2737 g_free(s->image_backing_file); 2738 g_free(s->image_backing_format); 2739 2740 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2741 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2742 2743 return qcow2_update_header(bs); 2744 } 2745 2746 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2747 { 2748 if (g_str_equal(encryptfmt, "luks")) { 2749 return QCOW_CRYPT_LUKS; 2750 } else if (g_str_equal(encryptfmt, "aes")) { 2751 return QCOW_CRYPT_AES; 2752 } else { 2753 return -EINVAL; 2754 } 2755 } 2756 2757 static int qcow2_set_up_encryption(BlockDriverState *bs, 2758 QCryptoBlockCreateOptions *cryptoopts, 2759 Error **errp) 2760 { 2761 BDRVQcow2State *s = bs->opaque; 2762 QCryptoBlock *crypto = NULL; 2763 int fmt, ret; 2764 2765 switch (cryptoopts->format) { 2766 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 2767 fmt = QCOW_CRYPT_LUKS; 2768 break; 2769 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 2770 fmt = QCOW_CRYPT_AES; 2771 break; 2772 default: 2773 error_setg(errp, "Crypto format not supported in qcow2"); 2774 return -EINVAL; 2775 } 2776 2777 s->crypt_method_header = fmt; 2778 2779 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2780 qcow2_crypto_hdr_init_func, 2781 qcow2_crypto_hdr_write_func, 2782 bs, errp); 2783 if (!crypto) { 2784 return -EINVAL; 2785 } 2786 2787 ret = qcow2_update_header(bs); 2788 if (ret < 0) { 2789 error_setg_errno(errp, -ret, "Could not write encryption header"); 2790 goto out; 2791 } 2792 2793 ret = 0; 2794 out: 2795 qcrypto_block_free(crypto); 2796 return ret; 2797 } 2798 2799 /** 2800 * Preallocates metadata structures for data clusters between @offset (in the 2801 * guest disk) and @new_length (which is thus generally the new guest disk 2802 * size). 2803 * 2804 * Returns: 0 on success, -errno on failure. 2805 */ 2806 static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, 2807 uint64_t new_length, PreallocMode mode, 2808 Error **errp) 2809 { 2810 BDRVQcow2State *s = bs->opaque; 2811 uint64_t bytes; 2812 uint64_t host_offset = 0; 2813 int64_t file_length; 2814 unsigned int cur_bytes; 2815 int ret; 2816 QCowL2Meta *meta; 2817 2818 assert(offset <= new_length); 2819 bytes = new_length - offset; 2820 2821 while (bytes) { 2822 cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size)); 2823 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2824 &host_offset, &meta); 2825 if (ret < 0) { 2826 error_setg_errno(errp, -ret, "Allocating clusters failed"); 2827 return ret; 2828 } 2829 2830 while (meta) { 2831 QCowL2Meta *next = meta->next; 2832 2833 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2834 if (ret < 0) { 2835 error_setg_errno(errp, -ret, "Mapping clusters failed"); 2836 qcow2_free_any_clusters(bs, meta->alloc_offset, 2837 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2838 return ret; 2839 } 2840 2841 /* There are no dependent requests, but we need to remove our 2842 * request from the list of in-flight requests */ 2843 QLIST_REMOVE(meta, next_in_flight); 2844 2845 g_free(meta); 2846 meta = next; 2847 } 2848 2849 /* TODO Preallocate data if requested */ 2850 2851 bytes -= cur_bytes; 2852 offset += cur_bytes; 2853 } 2854 2855 /* 2856 * It is expected that the image file is large enough to actually contain 2857 * all of the allocated clusters (otherwise we get failing reads after 2858 * EOF). Extend the image to the last allocated sector. 2859 */ 2860 file_length = bdrv_getlength(s->data_file->bs); 2861 if (file_length < 0) { 2862 error_setg_errno(errp, -file_length, "Could not get file size"); 2863 return file_length; 2864 } 2865 2866 if (host_offset + cur_bytes > file_length) { 2867 if (mode == PREALLOC_MODE_METADATA) { 2868 mode = PREALLOC_MODE_OFF; 2869 } 2870 ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, mode, 2871 errp); 2872 if (ret < 0) { 2873 return ret; 2874 } 2875 } 2876 2877 return 0; 2878 } 2879 2880 /* qcow2_refcount_metadata_size: 2881 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2882 * @cluster_size: size of a cluster, in bytes 2883 * @refcount_order: refcount bits power-of-2 exponent 2884 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2885 * needs to be 2886 * 2887 * Returns: Number of bytes required for refcount blocks and table metadata. 2888 */ 2889 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2890 int refcount_order, bool generous_increase, 2891 uint64_t *refblock_count) 2892 { 2893 /* 2894 * Every host cluster is reference-counted, including metadata (even 2895 * refcount metadata is recursively included). 2896 * 2897 * An accurate formula for the size of refcount metadata size is difficult 2898 * to derive. An easier method of calculation is finding the fixed point 2899 * where no further refcount blocks or table clusters are required to 2900 * reference count every cluster. 2901 */ 2902 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2903 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2904 int64_t table = 0; /* number of refcount table clusters */ 2905 int64_t blocks = 0; /* number of refcount block clusters */ 2906 int64_t last; 2907 int64_t n = 0; 2908 2909 do { 2910 last = n; 2911 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2912 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2913 n = clusters + blocks + table; 2914 2915 if (n == last && generous_increase) { 2916 clusters += DIV_ROUND_UP(table, 2); 2917 n = 0; /* force another loop */ 2918 generous_increase = false; 2919 } 2920 } while (n != last); 2921 2922 if (refblock_count) { 2923 *refblock_count = blocks; 2924 } 2925 2926 return (blocks + table) * cluster_size; 2927 } 2928 2929 /** 2930 * qcow2_calc_prealloc_size: 2931 * @total_size: virtual disk size in bytes 2932 * @cluster_size: cluster size in bytes 2933 * @refcount_order: refcount bits power-of-2 exponent 2934 * 2935 * Returns: Total number of bytes required for the fully allocated image 2936 * (including metadata). 2937 */ 2938 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2939 size_t cluster_size, 2940 int refcount_order) 2941 { 2942 int64_t meta_size = 0; 2943 uint64_t nl1e, nl2e; 2944 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); 2945 2946 /* header: 1 cluster */ 2947 meta_size += cluster_size; 2948 2949 /* total size of L2 tables */ 2950 nl2e = aligned_total_size / cluster_size; 2951 nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t)); 2952 meta_size += nl2e * sizeof(uint64_t); 2953 2954 /* total size of L1 tables */ 2955 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2956 nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t)); 2957 meta_size += nl1e * sizeof(uint64_t); 2958 2959 /* total size of refcount table and blocks */ 2960 meta_size += qcow2_refcount_metadata_size( 2961 (meta_size + aligned_total_size) / cluster_size, 2962 cluster_size, refcount_order, false, NULL); 2963 2964 return meta_size + aligned_total_size; 2965 } 2966 2967 static bool validate_cluster_size(size_t cluster_size, Error **errp) 2968 { 2969 int cluster_bits = ctz32(cluster_size); 2970 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2971 (1 << cluster_bits) != cluster_size) 2972 { 2973 error_setg(errp, "Cluster size must be a power of two between %d and " 2974 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2975 return false; 2976 } 2977 return true; 2978 } 2979 2980 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2981 { 2982 size_t cluster_size; 2983 2984 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2985 DEFAULT_CLUSTER_SIZE); 2986 if (!validate_cluster_size(cluster_size, errp)) { 2987 return 0; 2988 } 2989 return cluster_size; 2990 } 2991 2992 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2993 { 2994 char *buf; 2995 int ret; 2996 2997 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2998 if (!buf) { 2999 ret = 3; /* default */ 3000 } else if (!strcmp(buf, "0.10")) { 3001 ret = 2; 3002 } else if (!strcmp(buf, "1.1")) { 3003 ret = 3; 3004 } else { 3005 error_setg(errp, "Invalid compatibility level: '%s'", buf); 3006 ret = -EINVAL; 3007 } 3008 g_free(buf); 3009 return ret; 3010 } 3011 3012 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 3013 Error **errp) 3014 { 3015 uint64_t refcount_bits; 3016 3017 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 3018 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 3019 error_setg(errp, "Refcount width must be a power of two and may not " 3020 "exceed 64 bits"); 3021 return 0; 3022 } 3023 3024 if (version < 3 && refcount_bits != 16) { 3025 error_setg(errp, "Different refcount widths than 16 bits require " 3026 "compatibility level 1.1 or above (use compat=1.1 or " 3027 "greater)"); 3028 return 0; 3029 } 3030 3031 return refcount_bits; 3032 } 3033 3034 static int coroutine_fn 3035 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 3036 { 3037 BlockdevCreateOptionsQcow2 *qcow2_opts; 3038 QDict *options; 3039 3040 /* 3041 * Open the image file and write a minimal qcow2 header. 3042 * 3043 * We keep things simple and start with a zero-sized image. We also 3044 * do without refcount blocks or a L1 table for now. We'll fix the 3045 * inconsistency later. 3046 * 3047 * We do need a refcount table because growing the refcount table means 3048 * allocating two new refcount blocks - the seconds of which would be at 3049 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 3050 * size for any qcow2 image. 3051 */ 3052 BlockBackend *blk = NULL; 3053 BlockDriverState *bs = NULL; 3054 BlockDriverState *data_bs = NULL; 3055 QCowHeader *header; 3056 size_t cluster_size; 3057 int version; 3058 int refcount_order; 3059 uint64_t* refcount_table; 3060 Error *local_err = NULL; 3061 int ret; 3062 3063 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); 3064 qcow2_opts = &create_options->u.qcow2; 3065 3066 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); 3067 if (bs == NULL) { 3068 return -EIO; 3069 } 3070 3071 /* Validate options and set default values */ 3072 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { 3073 error_setg(errp, "Image size must be a multiple of 512 bytes"); 3074 ret = -EINVAL; 3075 goto out; 3076 } 3077 3078 if (qcow2_opts->has_version) { 3079 switch (qcow2_opts->version) { 3080 case BLOCKDEV_QCOW2_VERSION_V2: 3081 version = 2; 3082 break; 3083 case BLOCKDEV_QCOW2_VERSION_V3: 3084 version = 3; 3085 break; 3086 default: 3087 g_assert_not_reached(); 3088 } 3089 } else { 3090 version = 3; 3091 } 3092 3093 if (qcow2_opts->has_cluster_size) { 3094 cluster_size = qcow2_opts->cluster_size; 3095 } else { 3096 cluster_size = DEFAULT_CLUSTER_SIZE; 3097 } 3098 3099 if (!validate_cluster_size(cluster_size, errp)) { 3100 ret = -EINVAL; 3101 goto out; 3102 } 3103 3104 if (!qcow2_opts->has_preallocation) { 3105 qcow2_opts->preallocation = PREALLOC_MODE_OFF; 3106 } 3107 if (qcow2_opts->has_backing_file && 3108 qcow2_opts->preallocation != PREALLOC_MODE_OFF) 3109 { 3110 error_setg(errp, "Backing file and preallocation cannot be used at " 3111 "the same time"); 3112 ret = -EINVAL; 3113 goto out; 3114 } 3115 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { 3116 error_setg(errp, "Backing format cannot be used without backing file"); 3117 ret = -EINVAL; 3118 goto out; 3119 } 3120 3121 if (!qcow2_opts->has_lazy_refcounts) { 3122 qcow2_opts->lazy_refcounts = false; 3123 } 3124 if (version < 3 && qcow2_opts->lazy_refcounts) { 3125 error_setg(errp, "Lazy refcounts only supported with compatibility " 3126 "level 1.1 and above (use version=v3 or greater)"); 3127 ret = -EINVAL; 3128 goto out; 3129 } 3130 3131 if (!qcow2_opts->has_refcount_bits) { 3132 qcow2_opts->refcount_bits = 16; 3133 } 3134 if (qcow2_opts->refcount_bits > 64 || 3135 !is_power_of_2(qcow2_opts->refcount_bits)) 3136 { 3137 error_setg(errp, "Refcount width must be a power of two and may not " 3138 "exceed 64 bits"); 3139 ret = -EINVAL; 3140 goto out; 3141 } 3142 if (version < 3 && qcow2_opts->refcount_bits != 16) { 3143 error_setg(errp, "Different refcount widths than 16 bits require " 3144 "compatibility level 1.1 or above (use version=v3 or " 3145 "greater)"); 3146 ret = -EINVAL; 3147 goto out; 3148 } 3149 refcount_order = ctz32(qcow2_opts->refcount_bits); 3150 3151 if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) { 3152 error_setg(errp, "data-file-raw requires data-file"); 3153 ret = -EINVAL; 3154 goto out; 3155 } 3156 if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) { 3157 error_setg(errp, "Backing file and data-file-raw cannot be used at " 3158 "the same time"); 3159 ret = -EINVAL; 3160 goto out; 3161 } 3162 3163 if (qcow2_opts->data_file) { 3164 if (version < 3) { 3165 error_setg(errp, "External data files are only supported with " 3166 "compatibility level 1.1 and above (use version=v3 or " 3167 "greater)"); 3168 ret = -EINVAL; 3169 goto out; 3170 } 3171 data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp); 3172 if (data_bs == NULL) { 3173 ret = -EIO; 3174 goto out; 3175 } 3176 } 3177 3178 /* Create BlockBackend to write to the image */ 3179 blk = blk_new(bdrv_get_aio_context(bs), 3180 BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 3181 ret = blk_insert_bs(blk, bs, errp); 3182 if (ret < 0) { 3183 goto out; 3184 } 3185 blk_set_allow_write_beyond_eof(blk, true); 3186 3187 /* Clear the protocol layer and preallocate it if necessary */ 3188 ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); 3189 if (ret < 0) { 3190 goto out; 3191 } 3192 3193 /* Write the header */ 3194 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 3195 header = g_malloc0(cluster_size); 3196 *header = (QCowHeader) { 3197 .magic = cpu_to_be32(QCOW_MAGIC), 3198 .version = cpu_to_be32(version), 3199 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 3200 .size = cpu_to_be64(0), 3201 .l1_table_offset = cpu_to_be64(0), 3202 .l1_size = cpu_to_be32(0), 3203 .refcount_table_offset = cpu_to_be64(cluster_size), 3204 .refcount_table_clusters = cpu_to_be32(1), 3205 .refcount_order = cpu_to_be32(refcount_order), 3206 .header_length = cpu_to_be32(sizeof(*header)), 3207 }; 3208 3209 /* We'll update this to correct value later */ 3210 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 3211 3212 if (qcow2_opts->lazy_refcounts) { 3213 header->compatible_features |= 3214 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 3215 } 3216 if (data_bs) { 3217 header->incompatible_features |= 3218 cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE); 3219 } 3220 if (qcow2_opts->data_file_raw) { 3221 header->autoclear_features |= 3222 cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW); 3223 } 3224 3225 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 3226 g_free(header); 3227 if (ret < 0) { 3228 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 3229 goto out; 3230 } 3231 3232 /* Write a refcount table with one refcount block */ 3233 refcount_table = g_malloc0(2 * cluster_size); 3234 refcount_table[0] = cpu_to_be64(2 * cluster_size); 3235 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 3236 g_free(refcount_table); 3237 3238 if (ret < 0) { 3239 error_setg_errno(errp, -ret, "Could not write refcount table"); 3240 goto out; 3241 } 3242 3243 blk_unref(blk); 3244 blk = NULL; 3245 3246 /* 3247 * And now open the image and make it consistent first (i.e. increase the 3248 * refcount of the cluster that is occupied by the header and the refcount 3249 * table) 3250 */ 3251 options = qdict_new(); 3252 qdict_put_str(options, "driver", "qcow2"); 3253 qdict_put_str(options, "file", bs->node_name); 3254 if (data_bs) { 3255 qdict_put_str(options, "data-file", data_bs->node_name); 3256 } 3257 blk = blk_new_open(NULL, NULL, options, 3258 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 3259 &local_err); 3260 if (blk == NULL) { 3261 error_propagate(errp, local_err); 3262 ret = -EIO; 3263 goto out; 3264 } 3265 3266 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 3267 if (ret < 0) { 3268 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 3269 "header and refcount table"); 3270 goto out; 3271 3272 } else if (ret != 0) { 3273 error_report("Huh, first cluster in empty image is already in use?"); 3274 abort(); 3275 } 3276 3277 /* Set the external data file if necessary */ 3278 if (data_bs) { 3279 BDRVQcow2State *s = blk_bs(blk)->opaque; 3280 s->image_data_file = g_strdup(data_bs->filename); 3281 } 3282 3283 /* Create a full header (including things like feature table) */ 3284 ret = qcow2_update_header(blk_bs(blk)); 3285 if (ret < 0) { 3286 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 3287 goto out; 3288 } 3289 3290 /* Okay, now that we have a valid image, let's give it the right size */ 3291 ret = blk_truncate(blk, qcow2_opts->size, qcow2_opts->preallocation, errp); 3292 if (ret < 0) { 3293 error_prepend(errp, "Could not resize image: "); 3294 goto out; 3295 } 3296 3297 /* Want a backing file? There you go.*/ 3298 if (qcow2_opts->has_backing_file) { 3299 const char *backing_format = NULL; 3300 3301 if (qcow2_opts->has_backing_fmt) { 3302 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); 3303 } 3304 3305 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, 3306 backing_format); 3307 if (ret < 0) { 3308 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 3309 "with format '%s'", qcow2_opts->backing_file, 3310 backing_format); 3311 goto out; 3312 } 3313 } 3314 3315 /* Want encryption? There you go. */ 3316 if (qcow2_opts->has_encrypt) { 3317 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); 3318 if (ret < 0) { 3319 goto out; 3320 } 3321 } 3322 3323 blk_unref(blk); 3324 blk = NULL; 3325 3326 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 3327 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 3328 * have to setup decryption context. We're not doing any I/O on the top 3329 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 3330 * not have effect. 3331 */ 3332 options = qdict_new(); 3333 qdict_put_str(options, "driver", "qcow2"); 3334 qdict_put_str(options, "file", bs->node_name); 3335 if (data_bs) { 3336 qdict_put_str(options, "data-file", data_bs->node_name); 3337 } 3338 blk = blk_new_open(NULL, NULL, options, 3339 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 3340 &local_err); 3341 if (blk == NULL) { 3342 error_propagate(errp, local_err); 3343 ret = -EIO; 3344 goto out; 3345 } 3346 3347 ret = 0; 3348 out: 3349 blk_unref(blk); 3350 bdrv_unref(bs); 3351 bdrv_unref(data_bs); 3352 return ret; 3353 } 3354 3355 static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts, 3356 Error **errp) 3357 { 3358 BlockdevCreateOptions *create_options = NULL; 3359 QDict *qdict; 3360 Visitor *v; 3361 BlockDriverState *bs = NULL; 3362 BlockDriverState *data_bs = NULL; 3363 Error *local_err = NULL; 3364 const char *val; 3365 int ret; 3366 3367 /* Only the keyval visitor supports the dotted syntax needed for 3368 * encryption, so go through a QDict before getting a QAPI type. Ignore 3369 * options meant for the protocol layer so that the visitor doesn't 3370 * complain. */ 3371 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, 3372 true); 3373 3374 /* Handle encryption options */ 3375 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 3376 if (val && !strcmp(val, "on")) { 3377 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 3378 } else if (val && !strcmp(val, "off")) { 3379 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 3380 } 3381 3382 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 3383 if (val && !strcmp(val, "aes")) { 3384 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 3385 } 3386 3387 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into 3388 * version=v2/v3 below. */ 3389 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); 3390 if (val && !strcmp(val, "0.10")) { 3391 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); 3392 } else if (val && !strcmp(val, "1.1")) { 3393 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); 3394 } 3395 3396 /* Change legacy command line options into QMP ones */ 3397 static const QDictRenames opt_renames[] = { 3398 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 3399 { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, 3400 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, 3401 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, 3402 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, 3403 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 3404 { BLOCK_OPT_COMPAT_LEVEL, "version" }, 3405 { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" }, 3406 { NULL, NULL }, 3407 }; 3408 3409 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 3410 ret = -EINVAL; 3411 goto finish; 3412 } 3413 3414 /* Create and open the file (protocol layer) */ 3415 ret = bdrv_create_file(filename, opts, errp); 3416 if (ret < 0) { 3417 goto finish; 3418 } 3419 3420 bs = bdrv_open(filename, NULL, NULL, 3421 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 3422 if (bs == NULL) { 3423 ret = -EIO; 3424 goto finish; 3425 } 3426 3427 /* Create and open an external data file (protocol layer) */ 3428 val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE); 3429 if (val) { 3430 ret = bdrv_create_file(val, opts, errp); 3431 if (ret < 0) { 3432 goto finish; 3433 } 3434 3435 data_bs = bdrv_open(val, NULL, NULL, 3436 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 3437 errp); 3438 if (data_bs == NULL) { 3439 ret = -EIO; 3440 goto finish; 3441 } 3442 3443 qdict_del(qdict, BLOCK_OPT_DATA_FILE); 3444 qdict_put_str(qdict, "data-file", data_bs->node_name); 3445 } 3446 3447 /* Set 'driver' and 'node' options */ 3448 qdict_put_str(qdict, "driver", "qcow2"); 3449 qdict_put_str(qdict, "file", bs->node_name); 3450 3451 /* Now get the QAPI type BlockdevCreateOptions */ 3452 v = qobject_input_visitor_new_flat_confused(qdict, errp); 3453 if (!v) { 3454 ret = -EINVAL; 3455 goto finish; 3456 } 3457 3458 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 3459 visit_free(v); 3460 3461 if (local_err) { 3462 error_propagate(errp, local_err); 3463 ret = -EINVAL; 3464 goto finish; 3465 } 3466 3467 /* Silently round up size */ 3468 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, 3469 BDRV_SECTOR_SIZE); 3470 3471 /* Create the qcow2 image (format layer) */ 3472 ret = qcow2_co_create(create_options, errp); 3473 if (ret < 0) { 3474 goto finish; 3475 } 3476 3477 ret = 0; 3478 finish: 3479 qobject_unref(qdict); 3480 bdrv_unref(bs); 3481 bdrv_unref(data_bs); 3482 qapi_free_BlockdevCreateOptions(create_options); 3483 return ret; 3484 } 3485 3486 3487 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3488 { 3489 int64_t nr; 3490 int res; 3491 3492 /* Clamp to image length, before checking status of underlying sectors */ 3493 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3494 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3495 } 3496 3497 if (!bytes) { 3498 return true; 3499 } 3500 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3501 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3502 } 3503 3504 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3505 int64_t offset, int bytes, BdrvRequestFlags flags) 3506 { 3507 int ret; 3508 BDRVQcow2State *s = bs->opaque; 3509 3510 uint32_t head = offset % s->cluster_size; 3511 uint32_t tail = (offset + bytes) % s->cluster_size; 3512 3513 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3514 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3515 tail = 0; 3516 } 3517 3518 if (head || tail) { 3519 uint64_t off; 3520 unsigned int nr; 3521 3522 assert(head + bytes <= s->cluster_size); 3523 3524 /* check whether remainder of cluster already reads as zero */ 3525 if (!(is_zero(bs, offset - head, head) && 3526 is_zero(bs, offset + bytes, 3527 tail ? s->cluster_size - tail : 0))) { 3528 return -ENOTSUP; 3529 } 3530 3531 qemu_co_mutex_lock(&s->lock); 3532 /* We can have new write after previous check */ 3533 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3534 bytes = s->cluster_size; 3535 nr = s->cluster_size; 3536 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3537 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3538 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3539 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3540 qemu_co_mutex_unlock(&s->lock); 3541 return -ENOTSUP; 3542 } 3543 } else { 3544 qemu_co_mutex_lock(&s->lock); 3545 } 3546 3547 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3548 3549 /* Whatever is left can use real zero clusters */ 3550 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3551 qemu_co_mutex_unlock(&s->lock); 3552 3553 return ret; 3554 } 3555 3556 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3557 int64_t offset, int bytes) 3558 { 3559 int ret; 3560 BDRVQcow2State *s = bs->opaque; 3561 3562 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3563 assert(bytes < s->cluster_size); 3564 /* Ignore partial clusters, except for the special case of the 3565 * complete partial cluster at the end of an unaligned file */ 3566 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3567 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3568 return -ENOTSUP; 3569 } 3570 } 3571 3572 qemu_co_mutex_lock(&s->lock); 3573 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3574 false); 3575 qemu_co_mutex_unlock(&s->lock); 3576 return ret; 3577 } 3578 3579 static int coroutine_fn 3580 qcow2_co_copy_range_from(BlockDriverState *bs, 3581 BdrvChild *src, uint64_t src_offset, 3582 BdrvChild *dst, uint64_t dst_offset, 3583 uint64_t bytes, BdrvRequestFlags read_flags, 3584 BdrvRequestFlags write_flags) 3585 { 3586 BDRVQcow2State *s = bs->opaque; 3587 int ret; 3588 unsigned int cur_bytes; /* number of bytes in current iteration */ 3589 BdrvChild *child = NULL; 3590 BdrvRequestFlags cur_write_flags; 3591 3592 assert(!bs->encrypted); 3593 qemu_co_mutex_lock(&s->lock); 3594 3595 while (bytes != 0) { 3596 uint64_t copy_offset = 0; 3597 /* prepare next request */ 3598 cur_bytes = MIN(bytes, INT_MAX); 3599 cur_write_flags = write_flags; 3600 3601 ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, ©_offset); 3602 if (ret < 0) { 3603 goto out; 3604 } 3605 3606 switch (ret) { 3607 case QCOW2_CLUSTER_UNALLOCATED: 3608 if (bs->backing && bs->backing->bs) { 3609 int64_t backing_length = bdrv_getlength(bs->backing->bs); 3610 if (src_offset >= backing_length) { 3611 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3612 } else { 3613 child = bs->backing; 3614 cur_bytes = MIN(cur_bytes, backing_length - src_offset); 3615 copy_offset = src_offset; 3616 } 3617 } else { 3618 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3619 } 3620 break; 3621 3622 case QCOW2_CLUSTER_ZERO_PLAIN: 3623 case QCOW2_CLUSTER_ZERO_ALLOC: 3624 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3625 break; 3626 3627 case QCOW2_CLUSTER_COMPRESSED: 3628 ret = -ENOTSUP; 3629 goto out; 3630 3631 case QCOW2_CLUSTER_NORMAL: 3632 child = s->data_file; 3633 copy_offset += offset_into_cluster(s, src_offset); 3634 if ((copy_offset & 511) != 0) { 3635 ret = -EIO; 3636 goto out; 3637 } 3638 break; 3639 3640 default: 3641 abort(); 3642 } 3643 qemu_co_mutex_unlock(&s->lock); 3644 ret = bdrv_co_copy_range_from(child, 3645 copy_offset, 3646 dst, dst_offset, 3647 cur_bytes, read_flags, cur_write_flags); 3648 qemu_co_mutex_lock(&s->lock); 3649 if (ret < 0) { 3650 goto out; 3651 } 3652 3653 bytes -= cur_bytes; 3654 src_offset += cur_bytes; 3655 dst_offset += cur_bytes; 3656 } 3657 ret = 0; 3658 3659 out: 3660 qemu_co_mutex_unlock(&s->lock); 3661 return ret; 3662 } 3663 3664 static int coroutine_fn 3665 qcow2_co_copy_range_to(BlockDriverState *bs, 3666 BdrvChild *src, uint64_t src_offset, 3667 BdrvChild *dst, uint64_t dst_offset, 3668 uint64_t bytes, BdrvRequestFlags read_flags, 3669 BdrvRequestFlags write_flags) 3670 { 3671 BDRVQcow2State *s = bs->opaque; 3672 int offset_in_cluster; 3673 int ret; 3674 unsigned int cur_bytes; /* number of sectors in current iteration */ 3675 uint64_t cluster_offset; 3676 QCowL2Meta *l2meta = NULL; 3677 3678 assert(!bs->encrypted); 3679 3680 qemu_co_mutex_lock(&s->lock); 3681 3682 while (bytes != 0) { 3683 3684 l2meta = NULL; 3685 3686 offset_in_cluster = offset_into_cluster(s, dst_offset); 3687 cur_bytes = MIN(bytes, INT_MAX); 3688 3689 /* TODO: 3690 * If src->bs == dst->bs, we could simply copy by incrementing 3691 * the refcnt, without copying user data. 3692 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ 3693 ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes, 3694 &cluster_offset, &l2meta); 3695 if (ret < 0) { 3696 goto fail; 3697 } 3698 3699 assert((cluster_offset & 511) == 0); 3700 3701 ret = qcow2_pre_write_overlap_check(bs, 0, 3702 cluster_offset + offset_in_cluster, cur_bytes, true); 3703 if (ret < 0) { 3704 goto fail; 3705 } 3706 3707 qemu_co_mutex_unlock(&s->lock); 3708 ret = bdrv_co_copy_range_to(src, src_offset, 3709 s->data_file, 3710 cluster_offset + offset_in_cluster, 3711 cur_bytes, read_flags, write_flags); 3712 qemu_co_mutex_lock(&s->lock); 3713 if (ret < 0) { 3714 goto fail; 3715 } 3716 3717 ret = qcow2_handle_l2meta(bs, &l2meta, true); 3718 if (ret) { 3719 goto fail; 3720 } 3721 3722 bytes -= cur_bytes; 3723 src_offset += cur_bytes; 3724 dst_offset += cur_bytes; 3725 } 3726 ret = 0; 3727 3728 fail: 3729 qcow2_handle_l2meta(bs, &l2meta, false); 3730 3731 qemu_co_mutex_unlock(&s->lock); 3732 3733 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 3734 3735 return ret; 3736 } 3737 3738 static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, 3739 PreallocMode prealloc, Error **errp) 3740 { 3741 BDRVQcow2State *s = bs->opaque; 3742 uint64_t old_length; 3743 int64_t new_l1_size; 3744 int ret; 3745 QDict *options; 3746 3747 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3748 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3749 { 3750 error_setg(errp, "Unsupported preallocation mode '%s'", 3751 PreallocMode_str(prealloc)); 3752 return -ENOTSUP; 3753 } 3754 3755 if (offset & 511) { 3756 error_setg(errp, "The new size must be a multiple of 512"); 3757 return -EINVAL; 3758 } 3759 3760 qemu_co_mutex_lock(&s->lock); 3761 3762 /* cannot proceed if image has snapshots */ 3763 if (s->nb_snapshots) { 3764 error_setg(errp, "Can't resize an image which has snapshots"); 3765 ret = -ENOTSUP; 3766 goto fail; 3767 } 3768 3769 /* cannot proceed if image has bitmaps */ 3770 if (qcow2_truncate_bitmaps_check(bs, errp)) { 3771 ret = -ENOTSUP; 3772 goto fail; 3773 } 3774 3775 old_length = bs->total_sectors * BDRV_SECTOR_SIZE; 3776 new_l1_size = size_to_l1(s, offset); 3777 3778 if (offset < old_length) { 3779 int64_t last_cluster, old_file_size; 3780 if (prealloc != PREALLOC_MODE_OFF) { 3781 error_setg(errp, 3782 "Preallocation can't be used for shrinking an image"); 3783 ret = -EINVAL; 3784 goto fail; 3785 } 3786 3787 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3788 old_length - ROUND_UP(offset, 3789 s->cluster_size), 3790 QCOW2_DISCARD_ALWAYS, true); 3791 if (ret < 0) { 3792 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3793 goto fail; 3794 } 3795 3796 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3797 if (ret < 0) { 3798 error_setg_errno(errp, -ret, 3799 "Failed to reduce the number of L2 tables"); 3800 goto fail; 3801 } 3802 3803 ret = qcow2_shrink_reftable(bs); 3804 if (ret < 0) { 3805 error_setg_errno(errp, -ret, 3806 "Failed to discard unused refblocks"); 3807 goto fail; 3808 } 3809 3810 old_file_size = bdrv_getlength(bs->file->bs); 3811 if (old_file_size < 0) { 3812 error_setg_errno(errp, -old_file_size, 3813 "Failed to inquire current file length"); 3814 ret = old_file_size; 3815 goto fail; 3816 } 3817 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3818 if (last_cluster < 0) { 3819 error_setg_errno(errp, -last_cluster, 3820 "Failed to find the last cluster"); 3821 ret = last_cluster; 3822 goto fail; 3823 } 3824 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3825 Error *local_err = NULL; 3826 3827 bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3828 PREALLOC_MODE_OFF, &local_err); 3829 if (local_err) { 3830 warn_reportf_err(local_err, 3831 "Failed to truncate the tail of the image: "); 3832 } 3833 } 3834 } else { 3835 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3836 if (ret < 0) { 3837 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3838 goto fail; 3839 } 3840 } 3841 3842 switch (prealloc) { 3843 case PREALLOC_MODE_OFF: 3844 if (has_data_file(bs)) { 3845 ret = bdrv_co_truncate(s->data_file, offset, prealloc, errp); 3846 if (ret < 0) { 3847 goto fail; 3848 } 3849 } 3850 break; 3851 3852 case PREALLOC_MODE_METADATA: 3853 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 3854 if (ret < 0) { 3855 goto fail; 3856 } 3857 break; 3858 3859 case PREALLOC_MODE_FALLOC: 3860 case PREALLOC_MODE_FULL: 3861 { 3862 int64_t allocation_start, host_offset, guest_offset; 3863 int64_t clusters_allocated; 3864 int64_t old_file_size, new_file_size; 3865 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3866 3867 /* With a data file, preallocation means just allocating the metadata 3868 * and forwarding the truncate request to the data file */ 3869 if (has_data_file(bs)) { 3870 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 3871 if (ret < 0) { 3872 goto fail; 3873 } 3874 break; 3875 } 3876 3877 old_file_size = bdrv_getlength(bs->file->bs); 3878 if (old_file_size < 0) { 3879 error_setg_errno(errp, -old_file_size, 3880 "Failed to inquire current file length"); 3881 ret = old_file_size; 3882 goto fail; 3883 } 3884 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3885 3886 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3887 s->cluster_size); 3888 3889 /* This is an overestimation; we will not actually allocate space for 3890 * these in the file but just make sure the new refcount structures are 3891 * able to cover them so we will not have to allocate new refblocks 3892 * while entering the data blocks in the potentially new L2 tables. 3893 * (We do not actually care where the L2 tables are placed. Maybe they 3894 * are already allocated or they can be placed somewhere before 3895 * @old_file_size. It does not matter because they will be fully 3896 * allocated automatically, so they do not need to be covered by the 3897 * preallocation. All that matters is that we will not have to allocate 3898 * new refcount structures for them.) */ 3899 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3900 s->cluster_size / sizeof(uint64_t)); 3901 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3902 * table for a potential head/tail */ 3903 nb_new_l2_tables++; 3904 3905 allocation_start = qcow2_refcount_area(bs, old_file_size, 3906 nb_new_data_clusters + 3907 nb_new_l2_tables, 3908 true, 0, 0); 3909 if (allocation_start < 0) { 3910 error_setg_errno(errp, -allocation_start, 3911 "Failed to resize refcount structures"); 3912 ret = allocation_start; 3913 goto fail; 3914 } 3915 3916 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3917 nb_new_data_clusters); 3918 if (clusters_allocated < 0) { 3919 error_setg_errno(errp, -clusters_allocated, 3920 "Failed to allocate data clusters"); 3921 ret = clusters_allocated; 3922 goto fail; 3923 } 3924 3925 assert(clusters_allocated == nb_new_data_clusters); 3926 3927 /* Allocate the data area */ 3928 new_file_size = allocation_start + 3929 nb_new_data_clusters * s->cluster_size; 3930 ret = bdrv_co_truncate(bs->file, new_file_size, prealloc, errp); 3931 if (ret < 0) { 3932 error_prepend(errp, "Failed to resize underlying file: "); 3933 qcow2_free_clusters(bs, allocation_start, 3934 nb_new_data_clusters * s->cluster_size, 3935 QCOW2_DISCARD_OTHER); 3936 goto fail; 3937 } 3938 3939 /* Create the necessary L2 entries */ 3940 host_offset = allocation_start; 3941 guest_offset = old_length; 3942 while (nb_new_data_clusters) { 3943 int64_t nb_clusters = MIN( 3944 nb_new_data_clusters, 3945 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3946 QCowL2Meta allocation = { 3947 .offset = guest_offset, 3948 .alloc_offset = host_offset, 3949 .nb_clusters = nb_clusters, 3950 }; 3951 qemu_co_queue_init(&allocation.dependent_requests); 3952 3953 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3954 if (ret < 0) { 3955 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3956 qcow2_free_clusters(bs, host_offset, 3957 nb_new_data_clusters * s->cluster_size, 3958 QCOW2_DISCARD_OTHER); 3959 goto fail; 3960 } 3961 3962 guest_offset += nb_clusters * s->cluster_size; 3963 host_offset += nb_clusters * s->cluster_size; 3964 nb_new_data_clusters -= nb_clusters; 3965 } 3966 break; 3967 } 3968 3969 default: 3970 g_assert_not_reached(); 3971 } 3972 3973 if (prealloc != PREALLOC_MODE_OFF) { 3974 /* Flush metadata before actually changing the image size */ 3975 ret = qcow2_write_caches(bs); 3976 if (ret < 0) { 3977 error_setg_errno(errp, -ret, 3978 "Failed to flush the preallocated area to disk"); 3979 goto fail; 3980 } 3981 } 3982 3983 bs->total_sectors = offset / BDRV_SECTOR_SIZE; 3984 3985 /* write updated header.size */ 3986 offset = cpu_to_be64(offset); 3987 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3988 &offset, sizeof(uint64_t)); 3989 if (ret < 0) { 3990 error_setg_errno(errp, -ret, "Failed to update the image size"); 3991 goto fail; 3992 } 3993 3994 s->l1_vm_state_index = new_l1_size; 3995 3996 /* Update cache sizes */ 3997 options = qdict_clone_shallow(bs->options); 3998 ret = qcow2_update_options(bs, options, s->flags, errp); 3999 qobject_unref(options); 4000 if (ret < 0) { 4001 goto fail; 4002 } 4003 ret = 0; 4004 fail: 4005 qemu_co_mutex_unlock(&s->lock); 4006 return ret; 4007 } 4008 4009 /* XXX: put compressed sectors first, then all the cluster aligned 4010 tables to avoid losing bytes in alignment */ 4011 static coroutine_fn int 4012 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 4013 uint64_t bytes, QEMUIOVector *qiov) 4014 { 4015 BDRVQcow2State *s = bs->opaque; 4016 int ret; 4017 ssize_t out_len; 4018 uint8_t *buf, *out_buf; 4019 uint64_t cluster_offset; 4020 4021 if (has_data_file(bs)) { 4022 return -ENOTSUP; 4023 } 4024 4025 if (bytes == 0) { 4026 /* align end of file to a sector boundary to ease reading with 4027 sector based I/Os */ 4028 int64_t len = bdrv_getlength(bs->file->bs); 4029 if (len < 0) { 4030 return len; 4031 } 4032 return bdrv_co_truncate(bs->file, len, PREALLOC_MODE_OFF, NULL); 4033 } 4034 4035 if (offset_into_cluster(s, offset)) { 4036 return -EINVAL; 4037 } 4038 4039 buf = qemu_blockalign(bs, s->cluster_size); 4040 if (bytes != s->cluster_size) { 4041 if (bytes > s->cluster_size || 4042 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 4043 { 4044 qemu_vfree(buf); 4045 return -EINVAL; 4046 } 4047 /* Zero-pad last write if image size is not cluster aligned */ 4048 memset(buf + bytes, 0, s->cluster_size - bytes); 4049 } 4050 qemu_iovec_to_buf(qiov, 0, buf, bytes); 4051 4052 out_buf = g_malloc(s->cluster_size); 4053 4054 out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1, 4055 buf, s->cluster_size); 4056 if (out_len == -ENOMEM) { 4057 /* could not compress: write normal cluster */ 4058 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 4059 if (ret < 0) { 4060 goto fail; 4061 } 4062 goto success; 4063 } else if (out_len < 0) { 4064 ret = -EINVAL; 4065 goto fail; 4066 } 4067 4068 qemu_co_mutex_lock(&s->lock); 4069 ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len, 4070 &cluster_offset); 4071 if (ret < 0) { 4072 qemu_co_mutex_unlock(&s->lock); 4073 goto fail; 4074 } 4075 4076 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true); 4077 qemu_co_mutex_unlock(&s->lock); 4078 if (ret < 0) { 4079 goto fail; 4080 } 4081 4082 BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED); 4083 ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0); 4084 if (ret < 0) { 4085 goto fail; 4086 } 4087 success: 4088 ret = 0; 4089 fail: 4090 qemu_vfree(buf); 4091 g_free(out_buf); 4092 return ret; 4093 } 4094 4095 static int coroutine_fn 4096 qcow2_co_preadv_compressed(BlockDriverState *bs, 4097 uint64_t file_cluster_offset, 4098 uint64_t offset, 4099 uint64_t bytes, 4100 QEMUIOVector *qiov) 4101 { 4102 BDRVQcow2State *s = bs->opaque; 4103 int ret = 0, csize, nb_csectors; 4104 uint64_t coffset; 4105 uint8_t *buf, *out_buf; 4106 int offset_in_cluster = offset_into_cluster(s, offset); 4107 4108 coffset = file_cluster_offset & s->cluster_offset_mask; 4109 nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1; 4110 csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - 4111 (coffset & ~QCOW2_COMPRESSED_SECTOR_MASK); 4112 4113 buf = g_try_malloc(csize); 4114 if (!buf) { 4115 return -ENOMEM; 4116 } 4117 4118 out_buf = qemu_blockalign(bs, s->cluster_size); 4119 4120 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 4121 ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0); 4122 if (ret < 0) { 4123 goto fail; 4124 } 4125 4126 if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) { 4127 ret = -EIO; 4128 goto fail; 4129 } 4130 4131 qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes); 4132 4133 fail: 4134 qemu_vfree(out_buf); 4135 g_free(buf); 4136 4137 return ret; 4138 } 4139 4140 static int make_completely_empty(BlockDriverState *bs) 4141 { 4142 BDRVQcow2State *s = bs->opaque; 4143 Error *local_err = NULL; 4144 int ret, l1_clusters; 4145 int64_t offset; 4146 uint64_t *new_reftable = NULL; 4147 uint64_t rt_entry, l1_size2; 4148 struct { 4149 uint64_t l1_offset; 4150 uint64_t reftable_offset; 4151 uint32_t reftable_clusters; 4152 } QEMU_PACKED l1_ofs_rt_ofs_cls; 4153 4154 ret = qcow2_cache_empty(bs, s->l2_table_cache); 4155 if (ret < 0) { 4156 goto fail; 4157 } 4158 4159 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 4160 if (ret < 0) { 4161 goto fail; 4162 } 4163 4164 /* Refcounts will be broken utterly */ 4165 ret = qcow2_mark_dirty(bs); 4166 if (ret < 0) { 4167 goto fail; 4168 } 4169 4170 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4171 4172 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4173 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 4174 4175 /* After this call, neither the in-memory nor the on-disk refcount 4176 * information accurately describe the actual references */ 4177 4178 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 4179 l1_clusters * s->cluster_size, 0); 4180 if (ret < 0) { 4181 goto fail_broken_refcounts; 4182 } 4183 memset(s->l1_table, 0, l1_size2); 4184 4185 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 4186 4187 /* Overwrite enough clusters at the beginning of the sectors to place 4188 * the refcount table, a refcount block and the L1 table in; this may 4189 * overwrite parts of the existing refcount and L1 table, which is not 4190 * an issue because the dirty flag is set, complete data loss is in fact 4191 * desired and partial data loss is consequently fine as well */ 4192 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 4193 (2 + l1_clusters) * s->cluster_size, 0); 4194 /* This call (even if it failed overall) may have overwritten on-disk 4195 * refcount structures; in that case, the in-memory refcount information 4196 * will probably differ from the on-disk information which makes the BDS 4197 * unusable */ 4198 if (ret < 0) { 4199 goto fail_broken_refcounts; 4200 } 4201 4202 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4203 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 4204 4205 /* "Create" an empty reftable (one cluster) directly after the image 4206 * header and an empty L1 table three clusters after the image header; 4207 * the cluster between those two will be used as the first refblock */ 4208 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 4209 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 4210 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 4211 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 4212 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 4213 if (ret < 0) { 4214 goto fail_broken_refcounts; 4215 } 4216 4217 s->l1_table_offset = 3 * s->cluster_size; 4218 4219 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 4220 if (!new_reftable) { 4221 ret = -ENOMEM; 4222 goto fail_broken_refcounts; 4223 } 4224 4225 s->refcount_table_offset = s->cluster_size; 4226 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 4227 s->max_refcount_table_index = 0; 4228 4229 g_free(s->refcount_table); 4230 s->refcount_table = new_reftable; 4231 new_reftable = NULL; 4232 4233 /* Now the in-memory refcount information again corresponds to the on-disk 4234 * information (reftable is empty and no refblocks (the refblock cache is 4235 * empty)); however, this means some clusters (e.g. the image header) are 4236 * referenced, but not refcounted, but the normal qcow2 code assumes that 4237 * the in-memory information is always correct */ 4238 4239 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 4240 4241 /* Enter the first refblock into the reftable */ 4242 rt_entry = cpu_to_be64(2 * s->cluster_size); 4243 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 4244 &rt_entry, sizeof(rt_entry)); 4245 if (ret < 0) { 4246 goto fail_broken_refcounts; 4247 } 4248 s->refcount_table[0] = 2 * s->cluster_size; 4249 4250 s->free_cluster_index = 0; 4251 assert(3 + l1_clusters <= s->refcount_block_size); 4252 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 4253 if (offset < 0) { 4254 ret = offset; 4255 goto fail_broken_refcounts; 4256 } else if (offset > 0) { 4257 error_report("First cluster in emptied image is in use"); 4258 abort(); 4259 } 4260 4261 /* Now finally the in-memory information corresponds to the on-disk 4262 * structures and is correct */ 4263 ret = qcow2_mark_clean(bs); 4264 if (ret < 0) { 4265 goto fail; 4266 } 4267 4268 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 4269 PREALLOC_MODE_OFF, &local_err); 4270 if (ret < 0) { 4271 error_report_err(local_err); 4272 goto fail; 4273 } 4274 4275 return 0; 4276 4277 fail_broken_refcounts: 4278 /* The BDS is unusable at this point. If we wanted to make it usable, we 4279 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 4280 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 4281 * again. However, because the functions which could have caused this error 4282 * path to be taken are used by those functions as well, it's very likely 4283 * that that sequence will fail as well. Therefore, just eject the BDS. */ 4284 bs->drv = NULL; 4285 4286 fail: 4287 g_free(new_reftable); 4288 return ret; 4289 } 4290 4291 static int qcow2_make_empty(BlockDriverState *bs) 4292 { 4293 BDRVQcow2State *s = bs->opaque; 4294 uint64_t offset, end_offset; 4295 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 4296 int l1_clusters, ret = 0; 4297 4298 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4299 4300 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 4301 3 + l1_clusters <= s->refcount_block_size && 4302 s->crypt_method_header != QCOW_CRYPT_LUKS && 4303 !has_data_file(bs)) { 4304 /* The following function only works for qcow2 v3 images (it 4305 * requires the dirty flag) and only as long as there are no 4306 * features that reserve extra clusters (such as snapshots, 4307 * LUKS header, or persistent bitmaps), because it completely 4308 * empties the image. Furthermore, the L1 table and three 4309 * additional clusters (image header, refcount table, one 4310 * refcount block) have to fit inside one refcount block. It 4311 * only resets the image file, i.e. does not work with an 4312 * external data file. */ 4313 return make_completely_empty(bs); 4314 } 4315 4316 /* This fallback code simply discards every active cluster; this is slow, 4317 * but works in all cases */ 4318 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 4319 for (offset = 0; offset < end_offset; offset += step) { 4320 /* As this function is generally used after committing an external 4321 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 4322 * default action for this kind of discard is to pass the discard, 4323 * which will ideally result in an actually smaller image file, as 4324 * is probably desired. */ 4325 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 4326 QCOW2_DISCARD_SNAPSHOT, true); 4327 if (ret < 0) { 4328 break; 4329 } 4330 } 4331 4332 return ret; 4333 } 4334 4335 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 4336 { 4337 BDRVQcow2State *s = bs->opaque; 4338 int ret; 4339 4340 qemu_co_mutex_lock(&s->lock); 4341 ret = qcow2_write_caches(bs); 4342 qemu_co_mutex_unlock(&s->lock); 4343 4344 return ret; 4345 } 4346 4347 static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block, 4348 size_t headerlen, void *opaque, Error **errp) 4349 { 4350 size_t *headerlenp = opaque; 4351 4352 /* Stash away the payload size */ 4353 *headerlenp = headerlen; 4354 return 0; 4355 } 4356 4357 static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block, 4358 size_t offset, const uint8_t *buf, size_t buflen, 4359 void *opaque, Error **errp) 4360 { 4361 /* Discard the bytes, we're not actually writing to an image */ 4362 return buflen; 4363 } 4364 4365 /* Determine the number of bytes for the LUKS payload */ 4366 static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len, 4367 Error **errp) 4368 { 4369 QDict *opts_qdict; 4370 QDict *cryptoopts_qdict; 4371 QCryptoBlockCreateOptions *cryptoopts; 4372 QCryptoBlock *crypto; 4373 4374 /* Extract "encrypt." options into a qdict */ 4375 opts_qdict = qemu_opts_to_qdict(opts, NULL); 4376 qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt."); 4377 qobject_unref(opts_qdict); 4378 4379 /* Build QCryptoBlockCreateOptions object from qdict */ 4380 qdict_put_str(cryptoopts_qdict, "format", "luks"); 4381 cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp); 4382 qobject_unref(cryptoopts_qdict); 4383 if (!cryptoopts) { 4384 return false; 4385 } 4386 4387 /* Fake LUKS creation in order to determine the payload size */ 4388 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 4389 qcow2_measure_crypto_hdr_init_func, 4390 qcow2_measure_crypto_hdr_write_func, 4391 len, errp); 4392 qapi_free_QCryptoBlockCreateOptions(cryptoopts); 4393 if (!crypto) { 4394 return false; 4395 } 4396 4397 qcrypto_block_free(crypto); 4398 return true; 4399 } 4400 4401 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 4402 Error **errp) 4403 { 4404 Error *local_err = NULL; 4405 BlockMeasureInfo *info; 4406 uint64_t required = 0; /* bytes that contribute to required size */ 4407 uint64_t virtual_size; /* disk size as seen by guest */ 4408 uint64_t refcount_bits; 4409 uint64_t l2_tables; 4410 uint64_t luks_payload_size = 0; 4411 size_t cluster_size; 4412 int version; 4413 char *optstr; 4414 PreallocMode prealloc; 4415 bool has_backing_file; 4416 bool has_luks; 4417 4418 /* Parse image creation options */ 4419 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 4420 if (local_err) { 4421 goto err; 4422 } 4423 4424 version = qcow2_opt_get_version_del(opts, &local_err); 4425 if (local_err) { 4426 goto err; 4427 } 4428 4429 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 4430 if (local_err) { 4431 goto err; 4432 } 4433 4434 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 4435 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 4436 PREALLOC_MODE_OFF, &local_err); 4437 g_free(optstr); 4438 if (local_err) { 4439 goto err; 4440 } 4441 4442 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 4443 has_backing_file = !!optstr; 4444 g_free(optstr); 4445 4446 optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 4447 has_luks = optstr && strcmp(optstr, "luks") == 0; 4448 g_free(optstr); 4449 4450 if (has_luks) { 4451 size_t headerlen; 4452 4453 if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) { 4454 goto err; 4455 } 4456 4457 luks_payload_size = ROUND_UP(headerlen, cluster_size); 4458 } 4459 4460 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 4461 virtual_size = ROUND_UP(virtual_size, cluster_size); 4462 4463 /* Check that virtual disk size is valid */ 4464 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 4465 cluster_size / sizeof(uint64_t)); 4466 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 4467 error_setg(&local_err, "The image size is too large " 4468 "(try using a larger cluster size)"); 4469 goto err; 4470 } 4471 4472 /* Account for input image */ 4473 if (in_bs) { 4474 int64_t ssize = bdrv_getlength(in_bs); 4475 if (ssize < 0) { 4476 error_setg_errno(&local_err, -ssize, 4477 "Unable to get image virtual_size"); 4478 goto err; 4479 } 4480 4481 virtual_size = ROUND_UP(ssize, cluster_size); 4482 4483 if (has_backing_file) { 4484 /* We don't how much of the backing chain is shared by the input 4485 * image and the new image file. In the worst case the new image's 4486 * backing file has nothing in common with the input image. Be 4487 * conservative and assume all clusters need to be written. 4488 */ 4489 required = virtual_size; 4490 } else { 4491 int64_t offset; 4492 int64_t pnum = 0; 4493 4494 for (offset = 0; offset < ssize; offset += pnum) { 4495 int ret; 4496 4497 ret = bdrv_block_status_above(in_bs, NULL, offset, 4498 ssize - offset, &pnum, NULL, 4499 NULL); 4500 if (ret < 0) { 4501 error_setg_errno(&local_err, -ret, 4502 "Unable to get block status"); 4503 goto err; 4504 } 4505 4506 if (ret & BDRV_BLOCK_ZERO) { 4507 /* Skip zero regions (safe with no backing file) */ 4508 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 4509 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 4510 /* Extend pnum to end of cluster for next iteration */ 4511 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 4512 4513 /* Count clusters we've seen */ 4514 required += offset % cluster_size + pnum; 4515 } 4516 } 4517 } 4518 } 4519 4520 /* Take into account preallocation. Nothing special is needed for 4521 * PREALLOC_MODE_METADATA since metadata is always counted. 4522 */ 4523 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 4524 required = virtual_size; 4525 } 4526 4527 info = g_new(BlockMeasureInfo, 1); 4528 info->fully_allocated = 4529 qcow2_calc_prealloc_size(virtual_size, cluster_size, 4530 ctz32(refcount_bits)) + luks_payload_size; 4531 4532 /* Remove data clusters that are not required. This overestimates the 4533 * required size because metadata needed for the fully allocated file is 4534 * still counted. 4535 */ 4536 info->required = info->fully_allocated - virtual_size + required; 4537 return info; 4538 4539 err: 4540 error_propagate(errp, local_err); 4541 return NULL; 4542 } 4543 4544 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4545 { 4546 BDRVQcow2State *s = bs->opaque; 4547 bdi->unallocated_blocks_are_zero = true; 4548 bdi->cluster_size = s->cluster_size; 4549 bdi->vm_state_offset = qcow2_vm_state_offset(s); 4550 return 0; 4551 } 4552 4553 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, 4554 Error **errp) 4555 { 4556 BDRVQcow2State *s = bs->opaque; 4557 ImageInfoSpecific *spec_info; 4558 QCryptoBlockInfo *encrypt_info = NULL; 4559 Error *local_err = NULL; 4560 4561 if (s->crypto != NULL) { 4562 encrypt_info = qcrypto_block_get_info(s->crypto, &local_err); 4563 if (local_err) { 4564 error_propagate(errp, local_err); 4565 return NULL; 4566 } 4567 } 4568 4569 spec_info = g_new(ImageInfoSpecific, 1); 4570 *spec_info = (ImageInfoSpecific){ 4571 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 4572 .u.qcow2.data = g_new0(ImageInfoSpecificQCow2, 1), 4573 }; 4574 if (s->qcow_version == 2) { 4575 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4576 .compat = g_strdup("0.10"), 4577 .refcount_bits = s->refcount_bits, 4578 }; 4579 } else if (s->qcow_version == 3) { 4580 Qcow2BitmapInfoList *bitmaps; 4581 bitmaps = qcow2_get_bitmap_info_list(bs, &local_err); 4582 if (local_err) { 4583 error_propagate(errp, local_err); 4584 qapi_free_ImageInfoSpecific(spec_info); 4585 return NULL; 4586 } 4587 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4588 .compat = g_strdup("1.1"), 4589 .lazy_refcounts = s->compatible_features & 4590 QCOW2_COMPAT_LAZY_REFCOUNTS, 4591 .has_lazy_refcounts = true, 4592 .corrupt = s->incompatible_features & 4593 QCOW2_INCOMPAT_CORRUPT, 4594 .has_corrupt = true, 4595 .refcount_bits = s->refcount_bits, 4596 .has_bitmaps = !!bitmaps, 4597 .bitmaps = bitmaps, 4598 .has_data_file = !!s->image_data_file, 4599 .data_file = g_strdup(s->image_data_file), 4600 .has_data_file_raw = has_data_file(bs), 4601 .data_file_raw = data_file_is_raw(bs), 4602 }; 4603 } else { 4604 /* if this assertion fails, this probably means a new version was 4605 * added without having it covered here */ 4606 assert(false); 4607 } 4608 4609 if (encrypt_info) { 4610 ImageInfoSpecificQCow2Encryption *qencrypt = 4611 g_new(ImageInfoSpecificQCow2Encryption, 1); 4612 switch (encrypt_info->format) { 4613 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 4614 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 4615 break; 4616 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 4617 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 4618 qencrypt->u.luks = encrypt_info->u.luks; 4619 break; 4620 default: 4621 abort(); 4622 } 4623 /* Since we did shallow copy above, erase any pointers 4624 * in the original info */ 4625 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 4626 qapi_free_QCryptoBlockInfo(encrypt_info); 4627 4628 spec_info->u.qcow2.data->has_encrypt = true; 4629 spec_info->u.qcow2.data->encrypt = qencrypt; 4630 } 4631 4632 return spec_info; 4633 } 4634 4635 static int qcow2_has_zero_init(BlockDriverState *bs) 4636 { 4637 BDRVQcow2State *s = bs->opaque; 4638 bool preallocated; 4639 4640 if (qemu_in_coroutine()) { 4641 qemu_co_mutex_lock(&s->lock); 4642 } 4643 /* 4644 * Check preallocation status: Preallocated images have all L2 4645 * tables allocated, nonpreallocated images have none. It is 4646 * therefore enough to check the first one. 4647 */ 4648 preallocated = s->l1_size > 0 && s->l1_table[0] != 0; 4649 if (qemu_in_coroutine()) { 4650 qemu_co_mutex_unlock(&s->lock); 4651 } 4652 4653 if (!preallocated) { 4654 return 1; 4655 } else if (bs->encrypted) { 4656 return 0; 4657 } else { 4658 return bdrv_has_zero_init(s->data_file->bs); 4659 } 4660 } 4661 4662 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4663 int64_t pos) 4664 { 4665 BDRVQcow2State *s = bs->opaque; 4666 4667 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 4668 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 4669 qiov->size, qiov, 0); 4670 } 4671 4672 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4673 int64_t pos) 4674 { 4675 BDRVQcow2State *s = bs->opaque; 4676 4677 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 4678 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 4679 qiov->size, qiov, 0); 4680 } 4681 4682 /* 4683 * Downgrades an image's version. To achieve this, any incompatible features 4684 * have to be removed. 4685 */ 4686 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 4687 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 4688 Error **errp) 4689 { 4690 BDRVQcow2State *s = bs->opaque; 4691 int current_version = s->qcow_version; 4692 int ret; 4693 4694 /* This is qcow2_downgrade(), not qcow2_upgrade() */ 4695 assert(target_version < current_version); 4696 4697 /* There are no other versions (now) that you can downgrade to */ 4698 assert(target_version == 2); 4699 4700 if (s->refcount_order != 4) { 4701 error_setg(errp, "compat=0.10 requires refcount_bits=16"); 4702 return -ENOTSUP; 4703 } 4704 4705 if (has_data_file(bs)) { 4706 error_setg(errp, "Cannot downgrade an image with a data file"); 4707 return -ENOTSUP; 4708 } 4709 4710 /* clear incompatible features */ 4711 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 4712 ret = qcow2_mark_clean(bs); 4713 if (ret < 0) { 4714 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4715 return ret; 4716 } 4717 } 4718 4719 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 4720 * the first place; if that happens nonetheless, returning -ENOTSUP is the 4721 * best thing to do anyway */ 4722 4723 if (s->incompatible_features) { 4724 error_setg(errp, "Cannot downgrade an image with incompatible features " 4725 "%#" PRIx64 " set", s->incompatible_features); 4726 return -ENOTSUP; 4727 } 4728 4729 /* since we can ignore compatible features, we can set them to 0 as well */ 4730 s->compatible_features = 0; 4731 /* if lazy refcounts have been used, they have already been fixed through 4732 * clearing the dirty flag */ 4733 4734 /* clearing autoclear features is trivial */ 4735 s->autoclear_features = 0; 4736 4737 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 4738 if (ret < 0) { 4739 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); 4740 return ret; 4741 } 4742 4743 s->qcow_version = target_version; 4744 ret = qcow2_update_header(bs); 4745 if (ret < 0) { 4746 s->qcow_version = current_version; 4747 error_setg_errno(errp, -ret, "Failed to update the image header"); 4748 return ret; 4749 } 4750 return 0; 4751 } 4752 4753 typedef enum Qcow2AmendOperation { 4754 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 4755 * statically initialized to so that the helper CB can discern the first 4756 * invocation from an operation change */ 4757 QCOW2_NO_OPERATION = 0, 4758 4759 QCOW2_CHANGING_REFCOUNT_ORDER, 4760 QCOW2_DOWNGRADING, 4761 } Qcow2AmendOperation; 4762 4763 typedef struct Qcow2AmendHelperCBInfo { 4764 /* The code coordinating the amend operations should only modify 4765 * these four fields; the rest will be managed by the CB */ 4766 BlockDriverAmendStatusCB *original_status_cb; 4767 void *original_cb_opaque; 4768 4769 Qcow2AmendOperation current_operation; 4770 4771 /* Total number of operations to perform (only set once) */ 4772 int total_operations; 4773 4774 /* The following fields are managed by the CB */ 4775 4776 /* Number of operations completed */ 4777 int operations_completed; 4778 4779 /* Cumulative offset of all completed operations */ 4780 int64_t offset_completed; 4781 4782 Qcow2AmendOperation last_operation; 4783 int64_t last_work_size; 4784 } Qcow2AmendHelperCBInfo; 4785 4786 static void qcow2_amend_helper_cb(BlockDriverState *bs, 4787 int64_t operation_offset, 4788 int64_t operation_work_size, void *opaque) 4789 { 4790 Qcow2AmendHelperCBInfo *info = opaque; 4791 int64_t current_work_size; 4792 int64_t projected_work_size; 4793 4794 if (info->current_operation != info->last_operation) { 4795 if (info->last_operation != QCOW2_NO_OPERATION) { 4796 info->offset_completed += info->last_work_size; 4797 info->operations_completed++; 4798 } 4799 4800 info->last_operation = info->current_operation; 4801 } 4802 4803 assert(info->total_operations > 0); 4804 assert(info->operations_completed < info->total_operations); 4805 4806 info->last_work_size = operation_work_size; 4807 4808 current_work_size = info->offset_completed + operation_work_size; 4809 4810 /* current_work_size is the total work size for (operations_completed + 1) 4811 * operations (which includes this one), so multiply it by the number of 4812 * operations not covered and divide it by the number of operations 4813 * covered to get a projection for the operations not covered */ 4814 projected_work_size = current_work_size * (info->total_operations - 4815 info->operations_completed - 1) 4816 / (info->operations_completed + 1); 4817 4818 info->original_status_cb(bs, info->offset_completed + operation_offset, 4819 current_work_size + projected_work_size, 4820 info->original_cb_opaque); 4821 } 4822 4823 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4824 BlockDriverAmendStatusCB *status_cb, 4825 void *cb_opaque, 4826 Error **errp) 4827 { 4828 BDRVQcow2State *s = bs->opaque; 4829 int old_version = s->qcow_version, new_version = old_version; 4830 uint64_t new_size = 0; 4831 const char *backing_file = NULL, *backing_format = NULL, *data_file = NULL; 4832 bool lazy_refcounts = s->use_lazy_refcounts; 4833 bool data_file_raw = data_file_is_raw(bs); 4834 const char *compat = NULL; 4835 uint64_t cluster_size = s->cluster_size; 4836 bool encrypt; 4837 int encformat; 4838 int refcount_bits = s->refcount_bits; 4839 int ret; 4840 QemuOptDesc *desc = opts->list->desc; 4841 Qcow2AmendHelperCBInfo helper_cb_info; 4842 4843 while (desc && desc->name) { 4844 if (!qemu_opt_find(opts, desc->name)) { 4845 /* only change explicitly defined options */ 4846 desc++; 4847 continue; 4848 } 4849 4850 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4851 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4852 if (!compat) { 4853 /* preserve default */ 4854 } else if (!strcmp(compat, "0.10") || !strcmp(compat, "v2")) { 4855 new_version = 2; 4856 } else if (!strcmp(compat, "1.1") || !strcmp(compat, "v3")) { 4857 new_version = 3; 4858 } else { 4859 error_setg(errp, "Unknown compatibility level %s", compat); 4860 return -EINVAL; 4861 } 4862 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4863 error_setg(errp, "Cannot change preallocation mode"); 4864 return -ENOTSUP; 4865 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4866 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4867 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4868 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4869 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4870 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4871 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4872 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4873 !!s->crypto); 4874 4875 if (encrypt != !!s->crypto) { 4876 error_setg(errp, 4877 "Changing the encryption flag is not supported"); 4878 return -ENOTSUP; 4879 } 4880 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4881 encformat = qcow2_crypt_method_from_format( 4882 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4883 4884 if (encformat != s->crypt_method_header) { 4885 error_setg(errp, 4886 "Changing the encryption format is not supported"); 4887 return -ENOTSUP; 4888 } 4889 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4890 error_setg(errp, 4891 "Changing the encryption parameters is not supported"); 4892 return -ENOTSUP; 4893 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4894 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4895 cluster_size); 4896 if (cluster_size != s->cluster_size) { 4897 error_setg(errp, "Changing the cluster size is not supported"); 4898 return -ENOTSUP; 4899 } 4900 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4901 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4902 lazy_refcounts); 4903 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4904 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4905 refcount_bits); 4906 4907 if (refcount_bits <= 0 || refcount_bits > 64 || 4908 !is_power_of_2(refcount_bits)) 4909 { 4910 error_setg(errp, "Refcount width must be a power of two and " 4911 "may not exceed 64 bits"); 4912 return -EINVAL; 4913 } 4914 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) { 4915 data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE); 4916 if (data_file && !has_data_file(bs)) { 4917 error_setg(errp, "data-file can only be set for images that " 4918 "use an external data file"); 4919 return -EINVAL; 4920 } 4921 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) { 4922 data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW, 4923 data_file_raw); 4924 if (data_file_raw && !data_file_is_raw(bs)) { 4925 error_setg(errp, "data-file-raw cannot be set on existing " 4926 "images"); 4927 return -EINVAL; 4928 } 4929 } else { 4930 /* if this point is reached, this probably means a new option was 4931 * added without having it covered here */ 4932 abort(); 4933 } 4934 4935 desc++; 4936 } 4937 4938 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4939 .original_status_cb = status_cb, 4940 .original_cb_opaque = cb_opaque, 4941 .total_operations = (new_version < old_version) 4942 + (s->refcount_bits != refcount_bits) 4943 }; 4944 4945 /* Upgrade first (some features may require compat=1.1) */ 4946 if (new_version > old_version) { 4947 s->qcow_version = new_version; 4948 ret = qcow2_update_header(bs); 4949 if (ret < 0) { 4950 s->qcow_version = old_version; 4951 error_setg_errno(errp, -ret, "Failed to update the image header"); 4952 return ret; 4953 } 4954 } 4955 4956 if (s->refcount_bits != refcount_bits) { 4957 int refcount_order = ctz32(refcount_bits); 4958 4959 if (new_version < 3 && refcount_bits != 16) { 4960 error_setg(errp, "Refcount widths other than 16 bits require " 4961 "compatibility level 1.1 or above (use compat=1.1 or " 4962 "greater)"); 4963 return -EINVAL; 4964 } 4965 4966 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4967 ret = qcow2_change_refcount_order(bs, refcount_order, 4968 &qcow2_amend_helper_cb, 4969 &helper_cb_info, errp); 4970 if (ret < 0) { 4971 return ret; 4972 } 4973 } 4974 4975 /* data-file-raw blocks backing files, so clear it first if requested */ 4976 if (data_file_raw) { 4977 s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW; 4978 } else { 4979 s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW; 4980 } 4981 4982 if (data_file) { 4983 g_free(s->image_data_file); 4984 s->image_data_file = *data_file ? g_strdup(data_file) : NULL; 4985 } 4986 4987 ret = qcow2_update_header(bs); 4988 if (ret < 0) { 4989 error_setg_errno(errp, -ret, "Failed to update the image header"); 4990 return ret; 4991 } 4992 4993 if (backing_file || backing_format) { 4994 ret = qcow2_change_backing_file(bs, 4995 backing_file ?: s->image_backing_file, 4996 backing_format ?: s->image_backing_format); 4997 if (ret < 0) { 4998 error_setg_errno(errp, -ret, "Failed to change the backing file"); 4999 return ret; 5000 } 5001 } 5002 5003 if (s->use_lazy_refcounts != lazy_refcounts) { 5004 if (lazy_refcounts) { 5005 if (new_version < 3) { 5006 error_setg(errp, "Lazy refcounts only supported with " 5007 "compatibility level 1.1 and above (use compat=1.1 " 5008 "or greater)"); 5009 return -EINVAL; 5010 } 5011 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 5012 ret = qcow2_update_header(bs); 5013 if (ret < 0) { 5014 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 5015 error_setg_errno(errp, -ret, "Failed to update the image header"); 5016 return ret; 5017 } 5018 s->use_lazy_refcounts = true; 5019 } else { 5020 /* make image clean first */ 5021 ret = qcow2_mark_clean(bs); 5022 if (ret < 0) { 5023 error_setg_errno(errp, -ret, "Failed to make the image clean"); 5024 return ret; 5025 } 5026 /* now disallow lazy refcounts */ 5027 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 5028 ret = qcow2_update_header(bs); 5029 if (ret < 0) { 5030 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 5031 error_setg_errno(errp, -ret, "Failed to update the image header"); 5032 return ret; 5033 } 5034 s->use_lazy_refcounts = false; 5035 } 5036 } 5037 5038 if (new_size) { 5039 BlockBackend *blk = blk_new(bdrv_get_aio_context(bs), 5040 BLK_PERM_RESIZE, BLK_PERM_ALL); 5041 ret = blk_insert_bs(blk, bs, errp); 5042 if (ret < 0) { 5043 blk_unref(blk); 5044 return ret; 5045 } 5046 5047 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp); 5048 blk_unref(blk); 5049 if (ret < 0) { 5050 return ret; 5051 } 5052 } 5053 5054 /* Downgrade last (so unsupported features can be removed before) */ 5055 if (new_version < old_version) { 5056 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 5057 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 5058 &helper_cb_info, errp); 5059 if (ret < 0) { 5060 return ret; 5061 } 5062 } 5063 5064 return 0; 5065 } 5066 5067 /* 5068 * If offset or size are negative, respectively, they will not be included in 5069 * the BLOCK_IMAGE_CORRUPTED event emitted. 5070 * fatal will be ignored for read-only BDS; corruptions found there will always 5071 * be considered non-fatal. 5072 */ 5073 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 5074 int64_t size, const char *message_format, ...) 5075 { 5076 BDRVQcow2State *s = bs->opaque; 5077 const char *node_name; 5078 char *message; 5079 va_list ap; 5080 5081 fatal = fatal && bdrv_is_writable(bs); 5082 5083 if (s->signaled_corruption && 5084 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 5085 { 5086 return; 5087 } 5088 5089 va_start(ap, message_format); 5090 message = g_strdup_vprintf(message_format, ap); 5091 va_end(ap); 5092 5093 if (fatal) { 5094 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 5095 "corruption events will be suppressed\n", message); 5096 } else { 5097 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 5098 "corruption events will be suppressed\n", message); 5099 } 5100 5101 node_name = bdrv_get_node_name(bs); 5102 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 5103 *node_name != '\0', node_name, 5104 message, offset >= 0, offset, 5105 size >= 0, size, 5106 fatal); 5107 g_free(message); 5108 5109 if (fatal) { 5110 qcow2_mark_corrupt(bs); 5111 bs->drv = NULL; /* make BDS unusable */ 5112 } 5113 5114 s->signaled_corruption = true; 5115 } 5116 5117 static QemuOptsList qcow2_create_opts = { 5118 .name = "qcow2-create-opts", 5119 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 5120 .desc = { 5121 { 5122 .name = BLOCK_OPT_SIZE, 5123 .type = QEMU_OPT_SIZE, 5124 .help = "Virtual disk size" 5125 }, 5126 { 5127 .name = BLOCK_OPT_COMPAT_LEVEL, 5128 .type = QEMU_OPT_STRING, 5129 .help = "Compatibility level (v2 [0.10] or v3 [1.1])" 5130 }, 5131 { 5132 .name = BLOCK_OPT_BACKING_FILE, 5133 .type = QEMU_OPT_STRING, 5134 .help = "File name of a base image" 5135 }, 5136 { 5137 .name = BLOCK_OPT_BACKING_FMT, 5138 .type = QEMU_OPT_STRING, 5139 .help = "Image format of the base image" 5140 }, 5141 { 5142 .name = BLOCK_OPT_DATA_FILE, 5143 .type = QEMU_OPT_STRING, 5144 .help = "File name of an external data file" 5145 }, 5146 { 5147 .name = BLOCK_OPT_DATA_FILE_RAW, 5148 .type = QEMU_OPT_BOOL, 5149 .help = "The external data file must stay valid as a raw image" 5150 }, 5151 { 5152 .name = BLOCK_OPT_ENCRYPT, 5153 .type = QEMU_OPT_BOOL, 5154 .help = "Encrypt the image with format 'aes'. (Deprecated " 5155 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 5156 }, 5157 { 5158 .name = BLOCK_OPT_ENCRYPT_FORMAT, 5159 .type = QEMU_OPT_STRING, 5160 .help = "Encrypt the image, format choices: 'aes', 'luks'", 5161 }, 5162 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 5163 "ID of secret providing qcow AES key or LUKS passphrase"), 5164 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 5165 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 5166 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 5167 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 5168 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 5169 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 5170 { 5171 .name = BLOCK_OPT_CLUSTER_SIZE, 5172 .type = QEMU_OPT_SIZE, 5173 .help = "qcow2 cluster size", 5174 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 5175 }, 5176 { 5177 .name = BLOCK_OPT_PREALLOC, 5178 .type = QEMU_OPT_STRING, 5179 .help = "Preallocation mode (allowed values: off, metadata, " 5180 "falloc, full)" 5181 }, 5182 { 5183 .name = BLOCK_OPT_LAZY_REFCOUNTS, 5184 .type = QEMU_OPT_BOOL, 5185 .help = "Postpone refcount updates", 5186 .def_value_str = "off" 5187 }, 5188 { 5189 .name = BLOCK_OPT_REFCOUNT_BITS, 5190 .type = QEMU_OPT_NUMBER, 5191 .help = "Width of a reference count entry in bits", 5192 .def_value_str = "16" 5193 }, 5194 { /* end of list */ } 5195 } 5196 }; 5197 5198 static const char *const qcow2_strong_runtime_opts[] = { 5199 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 5200 5201 NULL 5202 }; 5203 5204 BlockDriver bdrv_qcow2 = { 5205 .format_name = "qcow2", 5206 .instance_size = sizeof(BDRVQcow2State), 5207 .bdrv_probe = qcow2_probe, 5208 .bdrv_open = qcow2_open, 5209 .bdrv_close = qcow2_close, 5210 .bdrv_reopen_prepare = qcow2_reopen_prepare, 5211 .bdrv_reopen_commit = qcow2_reopen_commit, 5212 .bdrv_reopen_abort = qcow2_reopen_abort, 5213 .bdrv_join_options = qcow2_join_options, 5214 .bdrv_child_perm = bdrv_format_default_perms, 5215 .bdrv_co_create_opts = qcow2_co_create_opts, 5216 .bdrv_co_create = qcow2_co_create, 5217 .bdrv_has_zero_init = qcow2_has_zero_init, 5218 .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1, 5219 .bdrv_co_block_status = qcow2_co_block_status, 5220 5221 .bdrv_co_preadv = qcow2_co_preadv, 5222 .bdrv_co_pwritev = qcow2_co_pwritev, 5223 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 5224 5225 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 5226 .bdrv_co_pdiscard = qcow2_co_pdiscard, 5227 .bdrv_co_copy_range_from = qcow2_co_copy_range_from, 5228 .bdrv_co_copy_range_to = qcow2_co_copy_range_to, 5229 .bdrv_co_truncate = qcow2_co_truncate, 5230 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 5231 .bdrv_make_empty = qcow2_make_empty, 5232 5233 .bdrv_snapshot_create = qcow2_snapshot_create, 5234 .bdrv_snapshot_goto = qcow2_snapshot_goto, 5235 .bdrv_snapshot_delete = qcow2_snapshot_delete, 5236 .bdrv_snapshot_list = qcow2_snapshot_list, 5237 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 5238 .bdrv_measure = qcow2_measure, 5239 .bdrv_get_info = qcow2_get_info, 5240 .bdrv_get_specific_info = qcow2_get_specific_info, 5241 5242 .bdrv_save_vmstate = qcow2_save_vmstate, 5243 .bdrv_load_vmstate = qcow2_load_vmstate, 5244 5245 .supports_backing = true, 5246 .bdrv_change_backing_file = qcow2_change_backing_file, 5247 5248 .bdrv_refresh_limits = qcow2_refresh_limits, 5249 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, 5250 .bdrv_inactivate = qcow2_inactivate, 5251 5252 .create_opts = &qcow2_create_opts, 5253 .strong_runtime_opts = qcow2_strong_runtime_opts, 5254 .mutable_opts = mutable_opts, 5255 .bdrv_co_check = qcow2_co_check, 5256 .bdrv_amend_options = qcow2_amend_options, 5257 5258 .bdrv_detach_aio_context = qcow2_detach_aio_context, 5259 .bdrv_attach_aio_context = qcow2_attach_aio_context, 5260 5261 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 5262 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 5263 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 5264 }; 5265 5266 static void bdrv_qcow2_init(void) 5267 { 5268 bdrv_register(&bdrv_qcow2); 5269 } 5270 5271 block_init(bdrv_qcow2_init); 5272