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 size_t qiov_offset); 81 82 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 83 { 84 const QCowHeader *cow_header = (const void *)buf; 85 86 if (buf_size >= sizeof(QCowHeader) && 87 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 88 be32_to_cpu(cow_header->version) >= 2) 89 return 100; 90 else 91 return 0; 92 } 93 94 95 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 96 uint8_t *buf, size_t buflen, 97 void *opaque, Error **errp) 98 { 99 BlockDriverState *bs = opaque; 100 BDRVQcow2State *s = bs->opaque; 101 ssize_t ret; 102 103 if ((offset + buflen) > s->crypto_header.length) { 104 error_setg(errp, "Request for data outside of extension header"); 105 return -1; 106 } 107 108 ret = bdrv_pread(bs->file, 109 s->crypto_header.offset + offset, buf, buflen); 110 if (ret < 0) { 111 error_setg_errno(errp, -ret, "Could not read encryption header"); 112 return -1; 113 } 114 return ret; 115 } 116 117 118 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 119 void *opaque, Error **errp) 120 { 121 BlockDriverState *bs = opaque; 122 BDRVQcow2State *s = bs->opaque; 123 int64_t ret; 124 int64_t clusterlen; 125 126 ret = qcow2_alloc_clusters(bs, headerlen); 127 if (ret < 0) { 128 error_setg_errno(errp, -ret, 129 "Cannot allocate cluster for LUKS header size %zu", 130 headerlen); 131 return -1; 132 } 133 134 s->crypto_header.length = headerlen; 135 s->crypto_header.offset = ret; 136 137 /* Zero fill remaining space in cluster so it has predictable 138 * content in case of future spec changes */ 139 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 140 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0); 141 ret = bdrv_pwrite_zeroes(bs->file, 142 ret + headerlen, 143 clusterlen - headerlen, 0); 144 if (ret < 0) { 145 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 146 return -1; 147 } 148 149 return ret; 150 } 151 152 153 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 154 const uint8_t *buf, size_t buflen, 155 void *opaque, Error **errp) 156 { 157 BlockDriverState *bs = opaque; 158 BDRVQcow2State *s = bs->opaque; 159 ssize_t ret; 160 161 if ((offset + buflen) > s->crypto_header.length) { 162 error_setg(errp, "Request for data outside of extension header"); 163 return -1; 164 } 165 166 ret = bdrv_pwrite(bs->file, 167 s->crypto_header.offset + offset, buf, buflen); 168 if (ret < 0) { 169 error_setg_errno(errp, -ret, "Could not read encryption header"); 170 return -1; 171 } 172 return ret; 173 } 174 175 176 /* 177 * read qcow2 extension and fill bs 178 * start reading from start_offset 179 * finish reading upon magic of value 0 or when end_offset reached 180 * unknown magic is skipped (future extension this version knows nothing about) 181 * return 0 upon success, non-0 otherwise 182 */ 183 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 184 uint64_t end_offset, void **p_feature_table, 185 int flags, bool *need_update_header, 186 Error **errp) 187 { 188 BDRVQcow2State *s = bs->opaque; 189 QCowExtension ext; 190 uint64_t offset; 191 int ret; 192 Qcow2BitmapHeaderExt bitmaps_ext; 193 194 if (need_update_header != NULL) { 195 *need_update_header = false; 196 } 197 198 #ifdef DEBUG_EXT 199 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 200 #endif 201 offset = start_offset; 202 while (offset < end_offset) { 203 204 #ifdef DEBUG_EXT 205 /* Sanity check */ 206 if (offset > s->cluster_size) 207 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 208 209 printf("attempting to read extended header in offset %lu\n", offset); 210 #endif 211 212 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 213 if (ret < 0) { 214 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 215 "pread fail from offset %" PRIu64, offset); 216 return 1; 217 } 218 ext.magic = be32_to_cpu(ext.magic); 219 ext.len = be32_to_cpu(ext.len); 220 offset += sizeof(ext); 221 #ifdef DEBUG_EXT 222 printf("ext.magic = 0x%x\n", ext.magic); 223 #endif 224 if (offset > end_offset || ext.len > end_offset - offset) { 225 error_setg(errp, "Header extension too large"); 226 return -EINVAL; 227 } 228 229 switch (ext.magic) { 230 case QCOW2_EXT_MAGIC_END: 231 return 0; 232 233 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 234 if (ext.len >= sizeof(bs->backing_format)) { 235 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 236 " too large (>=%zu)", ext.len, 237 sizeof(bs->backing_format)); 238 return 2; 239 } 240 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 241 if (ret < 0) { 242 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 243 "Could not read format name"); 244 return 3; 245 } 246 bs->backing_format[ext.len] = '\0'; 247 s->image_backing_format = g_strdup(bs->backing_format); 248 #ifdef DEBUG_EXT 249 printf("Qcow2: Got format extension %s\n", bs->backing_format); 250 #endif 251 break; 252 253 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 254 if (p_feature_table != NULL) { 255 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 256 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 257 if (ret < 0) { 258 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 259 "Could not read table"); 260 return ret; 261 } 262 263 *p_feature_table = feature_table; 264 } 265 break; 266 267 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 268 unsigned int cflags = 0; 269 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 270 error_setg(errp, "CRYPTO header extension only " 271 "expected with LUKS encryption method"); 272 return -EINVAL; 273 } 274 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 275 error_setg(errp, "CRYPTO header extension size %u, " 276 "but expected size %zu", ext.len, 277 sizeof(Qcow2CryptoHeaderExtension)); 278 return -EINVAL; 279 } 280 281 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 282 if (ret < 0) { 283 error_setg_errno(errp, -ret, 284 "Unable to read CRYPTO header extension"); 285 return ret; 286 } 287 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 288 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 289 290 if ((s->crypto_header.offset % s->cluster_size) != 0) { 291 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 292 "not a multiple of cluster size '%u'", 293 s->crypto_header.offset, s->cluster_size); 294 return -EINVAL; 295 } 296 297 if (flags & BDRV_O_NO_IO) { 298 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 299 } 300 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 301 qcow2_crypto_hdr_read_func, 302 bs, cflags, QCOW2_MAX_THREADS, errp); 303 if (!s->crypto) { 304 return -EINVAL; 305 } 306 } break; 307 308 case QCOW2_EXT_MAGIC_BITMAPS: 309 if (ext.len != sizeof(bitmaps_ext)) { 310 error_setg_errno(errp, -ret, "bitmaps_ext: " 311 "Invalid extension length"); 312 return -EINVAL; 313 } 314 315 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 316 if (s->qcow_version < 3) { 317 /* Let's be a bit more specific */ 318 warn_report("This qcow2 v2 image contains bitmaps, but " 319 "they may have been modified by a program " 320 "without persistent bitmap support; so now " 321 "they must all be considered inconsistent"); 322 } else { 323 warn_report("a program lacking bitmap support " 324 "modified this file, so all bitmaps are now " 325 "considered inconsistent"); 326 } 327 error_printf("Some clusters may be leaked, " 328 "run 'qemu-img check -r' on the image " 329 "file to fix."); 330 if (need_update_header != NULL) { 331 /* Updating is needed to drop invalid bitmap extension. */ 332 *need_update_header = true; 333 } 334 break; 335 } 336 337 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 338 if (ret < 0) { 339 error_setg_errno(errp, -ret, "bitmaps_ext: " 340 "Could not read ext header"); 341 return ret; 342 } 343 344 if (bitmaps_ext.reserved32 != 0) { 345 error_setg_errno(errp, -ret, "bitmaps_ext: " 346 "Reserved field is not zero"); 347 return -EINVAL; 348 } 349 350 bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps); 351 bitmaps_ext.bitmap_directory_size = 352 be64_to_cpu(bitmaps_ext.bitmap_directory_size); 353 bitmaps_ext.bitmap_directory_offset = 354 be64_to_cpu(bitmaps_ext.bitmap_directory_offset); 355 356 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 357 error_setg(errp, 358 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 359 "exceeding the QEMU supported maximum of %d", 360 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 361 return -EINVAL; 362 } 363 364 if (bitmaps_ext.nb_bitmaps == 0) { 365 error_setg(errp, "found bitmaps extension with zero bitmaps"); 366 return -EINVAL; 367 } 368 369 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 370 error_setg(errp, "bitmaps_ext: " 371 "invalid bitmap directory offset"); 372 return -EINVAL; 373 } 374 375 if (bitmaps_ext.bitmap_directory_size > 376 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 377 error_setg(errp, "bitmaps_ext: " 378 "bitmap directory size (%" PRIu64 ") exceeds " 379 "the maximum supported size (%d)", 380 bitmaps_ext.bitmap_directory_size, 381 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 382 return -EINVAL; 383 } 384 385 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 386 s->bitmap_directory_offset = 387 bitmaps_ext.bitmap_directory_offset; 388 s->bitmap_directory_size = 389 bitmaps_ext.bitmap_directory_size; 390 391 #ifdef DEBUG_EXT 392 printf("Qcow2: Got bitmaps extension: " 393 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 394 s->bitmap_directory_offset, s->nb_bitmaps); 395 #endif 396 break; 397 398 case QCOW2_EXT_MAGIC_DATA_FILE: 399 { 400 s->image_data_file = g_malloc0(ext.len + 1); 401 ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len); 402 if (ret < 0) { 403 error_setg_errno(errp, -ret, 404 "ERROR: Could not read data file name"); 405 return ret; 406 } 407 #ifdef DEBUG_EXT 408 printf("Qcow2: Got external data file %s\n", s->image_data_file); 409 #endif 410 break; 411 } 412 413 default: 414 /* unknown magic - save it in case we need to rewrite the header */ 415 /* If you add a new feature, make sure to also update the fast 416 * path of qcow2_make_empty() to deal with it. */ 417 { 418 Qcow2UnknownHeaderExtension *uext; 419 420 uext = g_malloc0(sizeof(*uext) + ext.len); 421 uext->magic = ext.magic; 422 uext->len = ext.len; 423 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 424 425 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 426 if (ret < 0) { 427 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 428 "Could not read data"); 429 return ret; 430 } 431 } 432 break; 433 } 434 435 offset += ((ext.len + 7) & ~7); 436 } 437 438 return 0; 439 } 440 441 static void cleanup_unknown_header_ext(BlockDriverState *bs) 442 { 443 BDRVQcow2State *s = bs->opaque; 444 Qcow2UnknownHeaderExtension *uext, *next; 445 446 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 447 QLIST_REMOVE(uext, next); 448 g_free(uext); 449 } 450 } 451 452 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 453 uint64_t mask) 454 { 455 char *features = g_strdup(""); 456 char *old; 457 458 while (table && table->name[0] != '\0') { 459 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 460 if (mask & (1ULL << table->bit)) { 461 old = features; 462 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 463 table->name); 464 g_free(old); 465 mask &= ~(1ULL << table->bit); 466 } 467 } 468 table++; 469 } 470 471 if (mask) { 472 old = features; 473 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 474 old, *old ? ", " : "", mask); 475 g_free(old); 476 } 477 478 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 479 g_free(features); 480 } 481 482 /* 483 * Sets the dirty bit and flushes afterwards if necessary. 484 * 485 * The incompatible_features bit is only set if the image file header was 486 * updated successfully. Therefore it is not required to check the return 487 * value of this function. 488 */ 489 int qcow2_mark_dirty(BlockDriverState *bs) 490 { 491 BDRVQcow2State *s = bs->opaque; 492 uint64_t val; 493 int ret; 494 495 assert(s->qcow_version >= 3); 496 497 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 498 return 0; /* already dirty */ 499 } 500 501 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 502 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 503 &val, sizeof(val)); 504 if (ret < 0) { 505 return ret; 506 } 507 ret = bdrv_flush(bs->file->bs); 508 if (ret < 0) { 509 return ret; 510 } 511 512 /* Only treat image as dirty if the header was updated successfully */ 513 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 514 return 0; 515 } 516 517 /* 518 * Clears the dirty bit and flushes before if necessary. Only call this 519 * function when there are no pending requests, it does not guard against 520 * concurrent requests dirtying the image. 521 */ 522 static int qcow2_mark_clean(BlockDriverState *bs) 523 { 524 BDRVQcow2State *s = bs->opaque; 525 526 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 527 int ret; 528 529 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 530 531 ret = qcow2_flush_caches(bs); 532 if (ret < 0) { 533 return ret; 534 } 535 536 return qcow2_update_header(bs); 537 } 538 return 0; 539 } 540 541 /* 542 * Marks the image as corrupt. 543 */ 544 int qcow2_mark_corrupt(BlockDriverState *bs) 545 { 546 BDRVQcow2State *s = bs->opaque; 547 548 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 549 return qcow2_update_header(bs); 550 } 551 552 /* 553 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 554 * before if necessary. 555 */ 556 int qcow2_mark_consistent(BlockDriverState *bs) 557 { 558 BDRVQcow2State *s = bs->opaque; 559 560 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 561 int ret = qcow2_flush_caches(bs); 562 if (ret < 0) { 563 return ret; 564 } 565 566 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 567 return qcow2_update_header(bs); 568 } 569 return 0; 570 } 571 572 static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, 573 BdrvCheckResult *result, 574 BdrvCheckMode fix) 575 { 576 int ret = qcow2_check_refcounts(bs, result, fix); 577 if (ret < 0) { 578 return ret; 579 } 580 581 if (fix && result->check_errors == 0 && result->corruptions == 0) { 582 ret = qcow2_mark_clean(bs); 583 if (ret < 0) { 584 return ret; 585 } 586 return qcow2_mark_consistent(bs); 587 } 588 return ret; 589 } 590 591 static int coroutine_fn qcow2_co_check(BlockDriverState *bs, 592 BdrvCheckResult *result, 593 BdrvCheckMode fix) 594 { 595 BDRVQcow2State *s = bs->opaque; 596 int ret; 597 598 qemu_co_mutex_lock(&s->lock); 599 ret = qcow2_co_check_locked(bs, result, fix); 600 qemu_co_mutex_unlock(&s->lock); 601 return ret; 602 } 603 604 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, 605 uint64_t entries, size_t entry_len, 606 int64_t max_size_bytes, const char *table_name, 607 Error **errp) 608 { 609 BDRVQcow2State *s = bs->opaque; 610 611 if (entries > max_size_bytes / entry_len) { 612 error_setg(errp, "%s too large", table_name); 613 return -EFBIG; 614 } 615 616 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 617 * because values will be passed to qemu functions taking int64_t. */ 618 if ((INT64_MAX - entries * entry_len < offset) || 619 (offset_into_cluster(s, offset) != 0)) { 620 error_setg(errp, "%s offset invalid", table_name); 621 return -EINVAL; 622 } 623 624 return 0; 625 } 626 627 static const char *const mutable_opts[] = { 628 QCOW2_OPT_LAZY_REFCOUNTS, 629 QCOW2_OPT_DISCARD_REQUEST, 630 QCOW2_OPT_DISCARD_SNAPSHOT, 631 QCOW2_OPT_DISCARD_OTHER, 632 QCOW2_OPT_OVERLAP, 633 QCOW2_OPT_OVERLAP_TEMPLATE, 634 QCOW2_OPT_OVERLAP_MAIN_HEADER, 635 QCOW2_OPT_OVERLAP_ACTIVE_L1, 636 QCOW2_OPT_OVERLAP_ACTIVE_L2, 637 QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 638 QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 639 QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 640 QCOW2_OPT_OVERLAP_INACTIVE_L1, 641 QCOW2_OPT_OVERLAP_INACTIVE_L2, 642 QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 643 QCOW2_OPT_CACHE_SIZE, 644 QCOW2_OPT_L2_CACHE_SIZE, 645 QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 646 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 647 QCOW2_OPT_CACHE_CLEAN_INTERVAL, 648 NULL 649 }; 650 651 static QemuOptsList qcow2_runtime_opts = { 652 .name = "qcow2", 653 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 654 .desc = { 655 { 656 .name = QCOW2_OPT_LAZY_REFCOUNTS, 657 .type = QEMU_OPT_BOOL, 658 .help = "Postpone refcount updates", 659 }, 660 { 661 .name = QCOW2_OPT_DISCARD_REQUEST, 662 .type = QEMU_OPT_BOOL, 663 .help = "Pass guest discard requests to the layer below", 664 }, 665 { 666 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 667 .type = QEMU_OPT_BOOL, 668 .help = "Generate discard requests when snapshot related space " 669 "is freed", 670 }, 671 { 672 .name = QCOW2_OPT_DISCARD_OTHER, 673 .type = QEMU_OPT_BOOL, 674 .help = "Generate discard requests when other clusters are freed", 675 }, 676 { 677 .name = QCOW2_OPT_OVERLAP, 678 .type = QEMU_OPT_STRING, 679 .help = "Selects which overlap checks to perform from a range of " 680 "templates (none, constant, cached, all)", 681 }, 682 { 683 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 684 .type = QEMU_OPT_STRING, 685 .help = "Selects which overlap checks to perform from a range of " 686 "templates (none, constant, cached, all)", 687 }, 688 { 689 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 690 .type = QEMU_OPT_BOOL, 691 .help = "Check for unintended writes into the main qcow2 header", 692 }, 693 { 694 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 695 .type = QEMU_OPT_BOOL, 696 .help = "Check for unintended writes into the active L1 table", 697 }, 698 { 699 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 700 .type = QEMU_OPT_BOOL, 701 .help = "Check for unintended writes into an active L2 table", 702 }, 703 { 704 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 705 .type = QEMU_OPT_BOOL, 706 .help = "Check for unintended writes into the refcount table", 707 }, 708 { 709 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 710 .type = QEMU_OPT_BOOL, 711 .help = "Check for unintended writes into a refcount block", 712 }, 713 { 714 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 715 .type = QEMU_OPT_BOOL, 716 .help = "Check for unintended writes into the snapshot table", 717 }, 718 { 719 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 720 .type = QEMU_OPT_BOOL, 721 .help = "Check for unintended writes into an inactive L1 table", 722 }, 723 { 724 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 725 .type = QEMU_OPT_BOOL, 726 .help = "Check for unintended writes into an inactive L2 table", 727 }, 728 { 729 .name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 730 .type = QEMU_OPT_BOOL, 731 .help = "Check for unintended writes into the bitmap directory", 732 }, 733 { 734 .name = QCOW2_OPT_CACHE_SIZE, 735 .type = QEMU_OPT_SIZE, 736 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 737 "cache size", 738 }, 739 { 740 .name = QCOW2_OPT_L2_CACHE_SIZE, 741 .type = QEMU_OPT_SIZE, 742 .help = "Maximum L2 table cache size", 743 }, 744 { 745 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 746 .type = QEMU_OPT_SIZE, 747 .help = "Size of each entry in the L2 cache", 748 }, 749 { 750 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 751 .type = QEMU_OPT_SIZE, 752 .help = "Maximum refcount block cache size", 753 }, 754 { 755 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 756 .type = QEMU_OPT_NUMBER, 757 .help = "Clean unused cache entries after this time (in seconds)", 758 }, 759 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 760 "ID of secret providing qcow2 AES key or LUKS passphrase"), 761 { /* end of list */ } 762 }, 763 }; 764 765 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 766 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 767 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 768 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 769 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 770 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 771 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 772 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 773 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 774 [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 775 }; 776 777 static void cache_clean_timer_cb(void *opaque) 778 { 779 BlockDriverState *bs = opaque; 780 BDRVQcow2State *s = bs->opaque; 781 qcow2_cache_clean_unused(s->l2_table_cache); 782 qcow2_cache_clean_unused(s->refcount_block_cache); 783 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 784 (int64_t) s->cache_clean_interval * 1000); 785 } 786 787 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 788 { 789 BDRVQcow2State *s = bs->opaque; 790 if (s->cache_clean_interval > 0) { 791 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 792 SCALE_MS, cache_clean_timer_cb, 793 bs); 794 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 795 (int64_t) s->cache_clean_interval * 1000); 796 } 797 } 798 799 static void cache_clean_timer_del(BlockDriverState *bs) 800 { 801 BDRVQcow2State *s = bs->opaque; 802 if (s->cache_clean_timer) { 803 timer_del(s->cache_clean_timer); 804 timer_free(s->cache_clean_timer); 805 s->cache_clean_timer = NULL; 806 } 807 } 808 809 static void qcow2_detach_aio_context(BlockDriverState *bs) 810 { 811 cache_clean_timer_del(bs); 812 } 813 814 static void qcow2_attach_aio_context(BlockDriverState *bs, 815 AioContext *new_context) 816 { 817 cache_clean_timer_init(bs, new_context); 818 } 819 820 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 821 uint64_t *l2_cache_size, 822 uint64_t *l2_cache_entry_size, 823 uint64_t *refcount_cache_size, Error **errp) 824 { 825 BDRVQcow2State *s = bs->opaque; 826 uint64_t combined_cache_size, l2_cache_max_setting; 827 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 828 bool l2_cache_entry_size_set; 829 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; 830 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; 831 uint64_t max_l2_entries = DIV_ROUND_UP(virtual_disk_size, s->cluster_size); 832 /* An L2 table is always one cluster in size so the max cache size 833 * should be a multiple of the cluster size. */ 834 uint64_t max_l2_cache = ROUND_UP(max_l2_entries * sizeof(uint64_t), 835 s->cluster_size); 836 837 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 838 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 839 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 840 l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE); 841 842 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 843 l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 844 DEFAULT_L2_CACHE_MAX_SIZE); 845 *refcount_cache_size = qemu_opt_get_size(opts, 846 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 847 848 *l2_cache_entry_size = qemu_opt_get_size( 849 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 850 851 *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting); 852 853 if (combined_cache_size_set) { 854 if (l2_cache_size_set && refcount_cache_size_set) { 855 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 856 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 857 "at the same time"); 858 return; 859 } else if (l2_cache_size_set && 860 (l2_cache_max_setting > combined_cache_size)) { 861 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 862 QCOW2_OPT_CACHE_SIZE); 863 return; 864 } else if (*refcount_cache_size > combined_cache_size) { 865 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 866 QCOW2_OPT_CACHE_SIZE); 867 return; 868 } 869 870 if (l2_cache_size_set) { 871 *refcount_cache_size = combined_cache_size - *l2_cache_size; 872 } else if (refcount_cache_size_set) { 873 *l2_cache_size = combined_cache_size - *refcount_cache_size; 874 } else { 875 /* Assign as much memory as possible to the L2 cache, and 876 * use the remainder for the refcount cache */ 877 if (combined_cache_size >= max_l2_cache + min_refcount_cache) { 878 *l2_cache_size = max_l2_cache; 879 *refcount_cache_size = combined_cache_size - *l2_cache_size; 880 } else { 881 *refcount_cache_size = 882 MIN(combined_cache_size, min_refcount_cache); 883 *l2_cache_size = combined_cache_size - *refcount_cache_size; 884 } 885 } 886 } 887 888 /* 889 * If the L2 cache is not enough to cover the whole disk then 890 * default to 4KB entries. Smaller entries reduce the cost of 891 * loads and evictions and increase I/O performance. 892 */ 893 if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) { 894 *l2_cache_entry_size = MIN(s->cluster_size, 4096); 895 } 896 897 /* l2_cache_size and refcount_cache_size are ensured to have at least 898 * their minimum values in qcow2_update_options_prepare() */ 899 900 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 901 *l2_cache_entry_size > s->cluster_size || 902 !is_power_of_2(*l2_cache_entry_size)) { 903 error_setg(errp, "L2 cache entry size must be a power of two " 904 "between %d and the cluster size (%d)", 905 1 << MIN_CLUSTER_BITS, s->cluster_size); 906 return; 907 } 908 } 909 910 typedef struct Qcow2ReopenState { 911 Qcow2Cache *l2_table_cache; 912 Qcow2Cache *refcount_block_cache; 913 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 914 bool use_lazy_refcounts; 915 int overlap_check; 916 bool discard_passthrough[QCOW2_DISCARD_MAX]; 917 uint64_t cache_clean_interval; 918 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 919 } Qcow2ReopenState; 920 921 static int qcow2_update_options_prepare(BlockDriverState *bs, 922 Qcow2ReopenState *r, 923 QDict *options, int flags, 924 Error **errp) 925 { 926 BDRVQcow2State *s = bs->opaque; 927 QemuOpts *opts = NULL; 928 const char *opt_overlap_check, *opt_overlap_check_template; 929 int overlap_check_template = 0; 930 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 931 int i; 932 const char *encryptfmt; 933 QDict *encryptopts = NULL; 934 Error *local_err = NULL; 935 int ret; 936 937 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 938 encryptfmt = qdict_get_try_str(encryptopts, "format"); 939 940 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 941 qemu_opts_absorb_qdict(opts, options, &local_err); 942 if (local_err) { 943 error_propagate(errp, local_err); 944 ret = -EINVAL; 945 goto fail; 946 } 947 948 /* get L2 table/refcount block cache size from command line options */ 949 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 950 &refcount_cache_size, &local_err); 951 if (local_err) { 952 error_propagate(errp, local_err); 953 ret = -EINVAL; 954 goto fail; 955 } 956 957 l2_cache_size /= l2_cache_entry_size; 958 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 959 l2_cache_size = MIN_L2_CACHE_SIZE; 960 } 961 if (l2_cache_size > INT_MAX) { 962 error_setg(errp, "L2 cache size too big"); 963 ret = -EINVAL; 964 goto fail; 965 } 966 967 refcount_cache_size /= s->cluster_size; 968 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 969 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 970 } 971 if (refcount_cache_size > INT_MAX) { 972 error_setg(errp, "Refcount cache size too big"); 973 ret = -EINVAL; 974 goto fail; 975 } 976 977 /* alloc new L2 table/refcount block cache, flush old one */ 978 if (s->l2_table_cache) { 979 ret = qcow2_cache_flush(bs, s->l2_table_cache); 980 if (ret) { 981 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 982 goto fail; 983 } 984 } 985 986 if (s->refcount_block_cache) { 987 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 988 if (ret) { 989 error_setg_errno(errp, -ret, 990 "Failed to flush the refcount block cache"); 991 goto fail; 992 } 993 } 994 995 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 996 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 997 l2_cache_entry_size); 998 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 999 s->cluster_size); 1000 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 1001 error_setg(errp, "Could not allocate metadata caches"); 1002 ret = -ENOMEM; 1003 goto fail; 1004 } 1005 1006 /* New interval for cache cleanup timer */ 1007 r->cache_clean_interval = 1008 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 1009 DEFAULT_CACHE_CLEAN_INTERVAL); 1010 #ifndef CONFIG_LINUX 1011 if (r->cache_clean_interval != 0) { 1012 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 1013 " not supported on this host"); 1014 ret = -EINVAL; 1015 goto fail; 1016 } 1017 #endif 1018 if (r->cache_clean_interval > UINT_MAX) { 1019 error_setg(errp, "Cache clean interval too big"); 1020 ret = -EINVAL; 1021 goto fail; 1022 } 1023 1024 /* lazy-refcounts; flush if going from enabled to disabled */ 1025 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 1026 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 1027 if (r->use_lazy_refcounts && s->qcow_version < 3) { 1028 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 1029 "qemu 1.1 compatibility level"); 1030 ret = -EINVAL; 1031 goto fail; 1032 } 1033 1034 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 1035 ret = qcow2_mark_clean(bs); 1036 if (ret < 0) { 1037 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 1038 goto fail; 1039 } 1040 } 1041 1042 /* Overlap check options */ 1043 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 1044 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 1045 if (opt_overlap_check_template && opt_overlap_check && 1046 strcmp(opt_overlap_check_template, opt_overlap_check)) 1047 { 1048 error_setg(errp, "Conflicting values for qcow2 options '" 1049 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 1050 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 1051 ret = -EINVAL; 1052 goto fail; 1053 } 1054 if (!opt_overlap_check) { 1055 opt_overlap_check = opt_overlap_check_template ?: "cached"; 1056 } 1057 1058 if (!strcmp(opt_overlap_check, "none")) { 1059 overlap_check_template = 0; 1060 } else if (!strcmp(opt_overlap_check, "constant")) { 1061 overlap_check_template = QCOW2_OL_CONSTANT; 1062 } else if (!strcmp(opt_overlap_check, "cached")) { 1063 overlap_check_template = QCOW2_OL_CACHED; 1064 } else if (!strcmp(opt_overlap_check, "all")) { 1065 overlap_check_template = QCOW2_OL_ALL; 1066 } else { 1067 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1068 "'overlap-check'. Allowed are any of the following: " 1069 "none, constant, cached, all", opt_overlap_check); 1070 ret = -EINVAL; 1071 goto fail; 1072 } 1073 1074 r->overlap_check = 0; 1075 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1076 /* overlap-check defines a template bitmask, but every flag may be 1077 * overwritten through the associated boolean option */ 1078 r->overlap_check |= 1079 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1080 overlap_check_template & (1 << i)) << i; 1081 } 1082 1083 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 1084 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1085 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1086 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1087 flags & BDRV_O_UNMAP); 1088 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1089 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1090 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1091 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1092 1093 switch (s->crypt_method_header) { 1094 case QCOW_CRYPT_NONE: 1095 if (encryptfmt) { 1096 error_setg(errp, "No encryption in image header, but options " 1097 "specified format '%s'", encryptfmt); 1098 ret = -EINVAL; 1099 goto fail; 1100 } 1101 break; 1102 1103 case QCOW_CRYPT_AES: 1104 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1105 error_setg(errp, 1106 "Header reported 'aes' encryption format but " 1107 "options specify '%s'", encryptfmt); 1108 ret = -EINVAL; 1109 goto fail; 1110 } 1111 qdict_put_str(encryptopts, "format", "qcow"); 1112 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1113 break; 1114 1115 case QCOW_CRYPT_LUKS: 1116 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1117 error_setg(errp, 1118 "Header reported 'luks' encryption format but " 1119 "options specify '%s'", encryptfmt); 1120 ret = -EINVAL; 1121 goto fail; 1122 } 1123 qdict_put_str(encryptopts, "format", "luks"); 1124 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1125 break; 1126 1127 default: 1128 error_setg(errp, "Unsupported encryption method %d", 1129 s->crypt_method_header); 1130 break; 1131 } 1132 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1133 ret = -EINVAL; 1134 goto fail; 1135 } 1136 1137 ret = 0; 1138 fail: 1139 qobject_unref(encryptopts); 1140 qemu_opts_del(opts); 1141 opts = NULL; 1142 return ret; 1143 } 1144 1145 static void qcow2_update_options_commit(BlockDriverState *bs, 1146 Qcow2ReopenState *r) 1147 { 1148 BDRVQcow2State *s = bs->opaque; 1149 int i; 1150 1151 if (s->l2_table_cache) { 1152 qcow2_cache_destroy(s->l2_table_cache); 1153 } 1154 if (s->refcount_block_cache) { 1155 qcow2_cache_destroy(s->refcount_block_cache); 1156 } 1157 s->l2_table_cache = r->l2_table_cache; 1158 s->refcount_block_cache = r->refcount_block_cache; 1159 s->l2_slice_size = r->l2_slice_size; 1160 1161 s->overlap_check = r->overlap_check; 1162 s->use_lazy_refcounts = r->use_lazy_refcounts; 1163 1164 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1165 s->discard_passthrough[i] = r->discard_passthrough[i]; 1166 } 1167 1168 if (s->cache_clean_interval != r->cache_clean_interval) { 1169 cache_clean_timer_del(bs); 1170 s->cache_clean_interval = r->cache_clean_interval; 1171 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1172 } 1173 1174 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1175 s->crypto_opts = r->crypto_opts; 1176 } 1177 1178 static void qcow2_update_options_abort(BlockDriverState *bs, 1179 Qcow2ReopenState *r) 1180 { 1181 if (r->l2_table_cache) { 1182 qcow2_cache_destroy(r->l2_table_cache); 1183 } 1184 if (r->refcount_block_cache) { 1185 qcow2_cache_destroy(r->refcount_block_cache); 1186 } 1187 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1188 } 1189 1190 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1191 int flags, Error **errp) 1192 { 1193 Qcow2ReopenState r = {}; 1194 int ret; 1195 1196 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1197 if (ret >= 0) { 1198 qcow2_update_options_commit(bs, &r); 1199 } else { 1200 qcow2_update_options_abort(bs, &r); 1201 } 1202 1203 return ret; 1204 } 1205 1206 /* Called with s->lock held. */ 1207 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, 1208 int flags, Error **errp) 1209 { 1210 BDRVQcow2State *s = bs->opaque; 1211 unsigned int len, i; 1212 int ret = 0; 1213 QCowHeader header; 1214 Error *local_err = NULL; 1215 uint64_t ext_end; 1216 uint64_t l1_vm_state_index; 1217 bool update_header = false; 1218 1219 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1220 if (ret < 0) { 1221 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1222 goto fail; 1223 } 1224 header.magic = be32_to_cpu(header.magic); 1225 header.version = be32_to_cpu(header.version); 1226 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 1227 header.backing_file_size = be32_to_cpu(header.backing_file_size); 1228 header.size = be64_to_cpu(header.size); 1229 header.cluster_bits = be32_to_cpu(header.cluster_bits); 1230 header.crypt_method = be32_to_cpu(header.crypt_method); 1231 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 1232 header.l1_size = be32_to_cpu(header.l1_size); 1233 header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset); 1234 header.refcount_table_clusters = 1235 be32_to_cpu(header.refcount_table_clusters); 1236 header.snapshots_offset = be64_to_cpu(header.snapshots_offset); 1237 header.nb_snapshots = be32_to_cpu(header.nb_snapshots); 1238 1239 if (header.magic != QCOW_MAGIC) { 1240 error_setg(errp, "Image is not in qcow2 format"); 1241 ret = -EINVAL; 1242 goto fail; 1243 } 1244 if (header.version < 2 || header.version > 3) { 1245 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1246 ret = -ENOTSUP; 1247 goto fail; 1248 } 1249 1250 s->qcow_version = header.version; 1251 1252 /* Initialise cluster size */ 1253 if (header.cluster_bits < MIN_CLUSTER_BITS || 1254 header.cluster_bits > MAX_CLUSTER_BITS) { 1255 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1256 header.cluster_bits); 1257 ret = -EINVAL; 1258 goto fail; 1259 } 1260 1261 s->cluster_bits = header.cluster_bits; 1262 s->cluster_size = 1 << s->cluster_bits; 1263 1264 /* Initialise version 3 header fields */ 1265 if (header.version == 2) { 1266 header.incompatible_features = 0; 1267 header.compatible_features = 0; 1268 header.autoclear_features = 0; 1269 header.refcount_order = 4; 1270 header.header_length = 72; 1271 } else { 1272 header.incompatible_features = 1273 be64_to_cpu(header.incompatible_features); 1274 header.compatible_features = be64_to_cpu(header.compatible_features); 1275 header.autoclear_features = be64_to_cpu(header.autoclear_features); 1276 header.refcount_order = be32_to_cpu(header.refcount_order); 1277 header.header_length = be32_to_cpu(header.header_length); 1278 1279 if (header.header_length < 104) { 1280 error_setg(errp, "qcow2 header too short"); 1281 ret = -EINVAL; 1282 goto fail; 1283 } 1284 } 1285 1286 if (header.header_length > s->cluster_size) { 1287 error_setg(errp, "qcow2 header exceeds cluster size"); 1288 ret = -EINVAL; 1289 goto fail; 1290 } 1291 1292 if (header.header_length > sizeof(header)) { 1293 s->unknown_header_fields_size = header.header_length - sizeof(header); 1294 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1295 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1296 s->unknown_header_fields_size); 1297 if (ret < 0) { 1298 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1299 "fields"); 1300 goto fail; 1301 } 1302 } 1303 1304 if (header.backing_file_offset > s->cluster_size) { 1305 error_setg(errp, "Invalid backing file offset"); 1306 ret = -EINVAL; 1307 goto fail; 1308 } 1309 1310 if (header.backing_file_offset) { 1311 ext_end = header.backing_file_offset; 1312 } else { 1313 ext_end = 1 << header.cluster_bits; 1314 } 1315 1316 /* Handle feature bits */ 1317 s->incompatible_features = header.incompatible_features; 1318 s->compatible_features = header.compatible_features; 1319 s->autoclear_features = header.autoclear_features; 1320 1321 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1322 void *feature_table = NULL; 1323 qcow2_read_extensions(bs, header.header_length, ext_end, 1324 &feature_table, flags, NULL, NULL); 1325 report_unsupported_feature(errp, feature_table, 1326 s->incompatible_features & 1327 ~QCOW2_INCOMPAT_MASK); 1328 ret = -ENOTSUP; 1329 g_free(feature_table); 1330 goto fail; 1331 } 1332 1333 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1334 /* Corrupt images may not be written to unless they are being repaired 1335 */ 1336 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1337 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1338 "read/write"); 1339 ret = -EACCES; 1340 goto fail; 1341 } 1342 } 1343 1344 /* Check support for various header values */ 1345 if (header.refcount_order > 6) { 1346 error_setg(errp, "Reference count entry width too large; may not " 1347 "exceed 64 bits"); 1348 ret = -EINVAL; 1349 goto fail; 1350 } 1351 s->refcount_order = header.refcount_order; 1352 s->refcount_bits = 1 << s->refcount_order; 1353 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1354 s->refcount_max += s->refcount_max - 1; 1355 1356 s->crypt_method_header = header.crypt_method; 1357 if (s->crypt_method_header) { 1358 if (bdrv_uses_whitelist() && 1359 s->crypt_method_header == QCOW_CRYPT_AES) { 1360 error_setg(errp, 1361 "Use of AES-CBC encrypted qcow2 images is no longer " 1362 "supported in system emulators"); 1363 error_append_hint(errp, 1364 "You can use 'qemu-img convert' to convert your " 1365 "image to an alternative supported format, such " 1366 "as unencrypted qcow2, or raw with the LUKS " 1367 "format instead.\n"); 1368 ret = -ENOSYS; 1369 goto fail; 1370 } 1371 1372 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1373 s->crypt_physical_offset = false; 1374 } else { 1375 /* Assuming LUKS and any future crypt methods we 1376 * add will all use physical offsets, due to the 1377 * fact that the alternative is insecure... */ 1378 s->crypt_physical_offset = true; 1379 } 1380 1381 bs->encrypted = true; 1382 } 1383 1384 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1385 s->l2_size = 1 << s->l2_bits; 1386 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1387 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1388 s->refcount_block_size = 1 << s->refcount_block_bits; 1389 bs->total_sectors = header.size / BDRV_SECTOR_SIZE; 1390 s->csize_shift = (62 - (s->cluster_bits - 8)); 1391 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1392 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1393 1394 s->refcount_table_offset = header.refcount_table_offset; 1395 s->refcount_table_size = 1396 header.refcount_table_clusters << (s->cluster_bits - 3); 1397 1398 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1399 error_setg(errp, "Image does not contain a reference count table"); 1400 ret = -EINVAL; 1401 goto fail; 1402 } 1403 1404 ret = qcow2_validate_table(bs, s->refcount_table_offset, 1405 header.refcount_table_clusters, 1406 s->cluster_size, QCOW_MAX_REFTABLE_SIZE, 1407 "Reference count table", errp); 1408 if (ret < 0) { 1409 goto fail; 1410 } 1411 1412 /* The total size in bytes of the snapshot table is checked in 1413 * qcow2_read_snapshots() because the size of each snapshot is 1414 * variable and we don't know it yet. 1415 * Here we only check the offset and number of snapshots. */ 1416 ret = qcow2_validate_table(bs, header.snapshots_offset, 1417 header.nb_snapshots, 1418 sizeof(QCowSnapshotHeader), 1419 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, 1420 "Snapshot table", errp); 1421 if (ret < 0) { 1422 goto fail; 1423 } 1424 1425 /* read the level 1 table */ 1426 ret = qcow2_validate_table(bs, header.l1_table_offset, 1427 header.l1_size, sizeof(uint64_t), 1428 QCOW_MAX_L1_SIZE, "Active L1 table", errp); 1429 if (ret < 0) { 1430 goto fail; 1431 } 1432 s->l1_size = header.l1_size; 1433 s->l1_table_offset = header.l1_table_offset; 1434 1435 l1_vm_state_index = size_to_l1(s, header.size); 1436 if (l1_vm_state_index > INT_MAX) { 1437 error_setg(errp, "Image is too big"); 1438 ret = -EFBIG; 1439 goto fail; 1440 } 1441 s->l1_vm_state_index = l1_vm_state_index; 1442 1443 /* the L1 table must contain at least enough entries to put 1444 header.size bytes */ 1445 if (s->l1_size < s->l1_vm_state_index) { 1446 error_setg(errp, "L1 table is too small"); 1447 ret = -EINVAL; 1448 goto fail; 1449 } 1450 1451 if (s->l1_size > 0) { 1452 s->l1_table = qemu_try_blockalign(bs->file->bs, 1453 ROUND_UP(s->l1_size * sizeof(uint64_t), 512)); 1454 if (s->l1_table == NULL) { 1455 error_setg(errp, "Could not allocate L1 table"); 1456 ret = -ENOMEM; 1457 goto fail; 1458 } 1459 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1460 s->l1_size * sizeof(uint64_t)); 1461 if (ret < 0) { 1462 error_setg_errno(errp, -ret, "Could not read L1 table"); 1463 goto fail; 1464 } 1465 for(i = 0;i < s->l1_size; i++) { 1466 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 1467 } 1468 } 1469 1470 /* Parse driver-specific options */ 1471 ret = qcow2_update_options(bs, options, flags, errp); 1472 if (ret < 0) { 1473 goto fail; 1474 } 1475 1476 s->flags = flags; 1477 1478 ret = qcow2_refcount_init(bs); 1479 if (ret != 0) { 1480 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1481 goto fail; 1482 } 1483 1484 QLIST_INIT(&s->cluster_allocs); 1485 QTAILQ_INIT(&s->discards); 1486 1487 /* read qcow2 extensions */ 1488 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1489 flags, &update_header, &local_err)) { 1490 error_propagate(errp, local_err); 1491 ret = -EINVAL; 1492 goto fail; 1493 } 1494 1495 /* Open external data file */ 1496 s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file, 1497 true, &local_err); 1498 if (local_err) { 1499 error_propagate(errp, local_err); 1500 ret = -EINVAL; 1501 goto fail; 1502 } 1503 1504 if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { 1505 if (!s->data_file && s->image_data_file) { 1506 s->data_file = bdrv_open_child(s->image_data_file, options, 1507 "data-file", bs, &child_file, 1508 false, errp); 1509 if (!s->data_file) { 1510 ret = -EINVAL; 1511 goto fail; 1512 } 1513 } 1514 if (!s->data_file) { 1515 error_setg(errp, "'data-file' is required for this image"); 1516 ret = -EINVAL; 1517 goto fail; 1518 } 1519 } else { 1520 if (s->data_file) { 1521 error_setg(errp, "'data-file' can only be set for images with an " 1522 "external data file"); 1523 ret = -EINVAL; 1524 goto fail; 1525 } 1526 1527 s->data_file = bs->file; 1528 1529 if (data_file_is_raw(bs)) { 1530 error_setg(errp, "data-file-raw requires a data file"); 1531 ret = -EINVAL; 1532 goto fail; 1533 } 1534 } 1535 1536 /* qcow2_read_extension may have set up the crypto context 1537 * if the crypt method needs a header region, some methods 1538 * don't need header extensions, so must check here 1539 */ 1540 if (s->crypt_method_header && !s->crypto) { 1541 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1542 unsigned int cflags = 0; 1543 if (flags & BDRV_O_NO_IO) { 1544 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1545 } 1546 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1547 NULL, NULL, cflags, 1548 QCOW2_MAX_THREADS, errp); 1549 if (!s->crypto) { 1550 ret = -EINVAL; 1551 goto fail; 1552 } 1553 } else if (!(flags & BDRV_O_NO_IO)) { 1554 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1555 s->crypt_method_header); 1556 ret = -EINVAL; 1557 goto fail; 1558 } 1559 } 1560 1561 /* read the backing file name */ 1562 if (header.backing_file_offset != 0) { 1563 len = header.backing_file_size; 1564 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1565 len >= sizeof(bs->backing_file)) { 1566 error_setg(errp, "Backing file name too long"); 1567 ret = -EINVAL; 1568 goto fail; 1569 } 1570 ret = bdrv_pread(bs->file, header.backing_file_offset, 1571 bs->auto_backing_file, len); 1572 if (ret < 0) { 1573 error_setg_errno(errp, -ret, "Could not read backing file name"); 1574 goto fail; 1575 } 1576 bs->auto_backing_file[len] = '\0'; 1577 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1578 bs->auto_backing_file); 1579 s->image_backing_file = g_strdup(bs->auto_backing_file); 1580 } 1581 1582 /* Internal snapshots */ 1583 s->snapshots_offset = header.snapshots_offset; 1584 s->nb_snapshots = header.nb_snapshots; 1585 1586 ret = qcow2_read_snapshots(bs); 1587 if (ret < 0) { 1588 error_setg_errno(errp, -ret, "Could not read snapshots"); 1589 goto fail; 1590 } 1591 1592 /* Clear unknown autoclear feature bits */ 1593 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1594 update_header = 1595 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1596 if (update_header) { 1597 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1598 } 1599 1600 /* == Handle persistent dirty bitmaps == 1601 * 1602 * We want load dirty bitmaps in three cases: 1603 * 1604 * 1. Normal open of the disk in active mode, not related to invalidation 1605 * after migration. 1606 * 1607 * 2. Invalidation of the target vm after pre-copy phase of migration, if 1608 * bitmaps are _not_ migrating through migration channel, i.e. 1609 * 'dirty-bitmaps' capability is disabled. 1610 * 1611 * 3. Invalidation of source vm after failed or canceled migration. 1612 * This is a very interesting case. There are two possible types of 1613 * bitmaps: 1614 * 1615 * A. Stored on inactivation and removed. They should be loaded from the 1616 * image. 1617 * 1618 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through 1619 * the migration channel (with dirty-bitmaps capability). 1620 * 1621 * On the other hand, there are two possible sub-cases: 1622 * 1623 * 3.1 disk was changed by somebody else while were inactive. In this 1624 * case all in-RAM dirty bitmaps (both persistent and not) are 1625 * definitely invalid. And we don't have any method to determine 1626 * this. 1627 * 1628 * Simple and safe thing is to just drop all the bitmaps of type B on 1629 * inactivation. But in this case we lose bitmaps in valid 4.2 case. 1630 * 1631 * On the other hand, resuming source vm, if disk was already changed 1632 * is a bad thing anyway: not only bitmaps, the whole vm state is 1633 * out of sync with disk. 1634 * 1635 * This means, that user or management tool, who for some reason 1636 * decided to resume source vm, after disk was already changed by 1637 * target vm, should at least drop all dirty bitmaps by hand. 1638 * 1639 * So, we can ignore this case for now, but TODO: "generation" 1640 * extension for qcow2, to determine, that image was changed after 1641 * last inactivation. And if it is changed, we will drop (or at least 1642 * mark as 'invalid' all the bitmaps of type B, both persistent 1643 * and not). 1644 * 1645 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved 1646 * to disk ('dirty-bitmaps' capability disabled), or not saved 1647 * ('dirty-bitmaps' capability enabled), but we don't need to care 1648 * of: let's load bitmaps as always: stored bitmaps will be loaded, 1649 * and not stored has flag IN_USE=1 in the image and will be skipped 1650 * on loading. 1651 * 1652 * One remaining possible case when we don't want load bitmaps: 1653 * 1654 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or 1655 * will be loaded on invalidation, no needs try loading them before) 1656 */ 1657 1658 if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { 1659 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ 1660 bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); 1661 1662 update_header = update_header && !header_updated; 1663 } 1664 if (local_err != NULL) { 1665 error_propagate(errp, local_err); 1666 ret = -EINVAL; 1667 goto fail; 1668 } 1669 1670 if (update_header) { 1671 ret = qcow2_update_header(bs); 1672 if (ret < 0) { 1673 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1674 goto fail; 1675 } 1676 } 1677 1678 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1679 1680 /* Repair image if dirty */ 1681 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1682 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1683 BdrvCheckResult result = {0}; 1684 1685 ret = qcow2_co_check_locked(bs, &result, 1686 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1687 if (ret < 0 || result.check_errors) { 1688 if (ret >= 0) { 1689 ret = -EIO; 1690 } 1691 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1692 goto fail; 1693 } 1694 } 1695 1696 #ifdef DEBUG_ALLOC 1697 { 1698 BdrvCheckResult result = {0}; 1699 qcow2_check_refcounts(bs, &result, 0); 1700 } 1701 #endif 1702 1703 qemu_co_queue_init(&s->thread_task_queue); 1704 1705 return ret; 1706 1707 fail: 1708 g_free(s->image_data_file); 1709 if (has_data_file(bs)) { 1710 bdrv_unref_child(bs, s->data_file); 1711 } 1712 g_free(s->unknown_header_fields); 1713 cleanup_unknown_header_ext(bs); 1714 qcow2_free_snapshots(bs); 1715 qcow2_refcount_close(bs); 1716 qemu_vfree(s->l1_table); 1717 /* else pre-write overlap checks in cache_destroy may crash */ 1718 s->l1_table = NULL; 1719 cache_clean_timer_del(bs); 1720 if (s->l2_table_cache) { 1721 qcow2_cache_destroy(s->l2_table_cache); 1722 } 1723 if (s->refcount_block_cache) { 1724 qcow2_cache_destroy(s->refcount_block_cache); 1725 } 1726 qcrypto_block_free(s->crypto); 1727 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1728 return ret; 1729 } 1730 1731 typedef struct QCow2OpenCo { 1732 BlockDriverState *bs; 1733 QDict *options; 1734 int flags; 1735 Error **errp; 1736 int ret; 1737 } QCow2OpenCo; 1738 1739 static void coroutine_fn qcow2_open_entry(void *opaque) 1740 { 1741 QCow2OpenCo *qoc = opaque; 1742 BDRVQcow2State *s = qoc->bs->opaque; 1743 1744 qemu_co_mutex_lock(&s->lock); 1745 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); 1746 qemu_co_mutex_unlock(&s->lock); 1747 } 1748 1749 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1750 Error **errp) 1751 { 1752 BDRVQcow2State *s = bs->opaque; 1753 QCow2OpenCo qoc = { 1754 .bs = bs, 1755 .options = options, 1756 .flags = flags, 1757 .errp = errp, 1758 .ret = -EINPROGRESS 1759 }; 1760 1761 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1762 false, errp); 1763 if (!bs->file) { 1764 return -EINVAL; 1765 } 1766 1767 /* Initialise locks */ 1768 qemu_co_mutex_init(&s->lock); 1769 1770 if (qemu_in_coroutine()) { 1771 /* From bdrv_co_create. */ 1772 qcow2_open_entry(&qoc); 1773 } else { 1774 assert(qemu_get_current_aio_context() == qemu_get_aio_context()); 1775 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); 1776 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); 1777 } 1778 return qoc.ret; 1779 } 1780 1781 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1782 { 1783 BDRVQcow2State *s = bs->opaque; 1784 1785 if (bs->encrypted) { 1786 /* Encryption works on a sector granularity */ 1787 bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto); 1788 } 1789 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1790 bs->bl.pdiscard_alignment = s->cluster_size; 1791 } 1792 1793 static int qcow2_reopen_prepare(BDRVReopenState *state, 1794 BlockReopenQueue *queue, Error **errp) 1795 { 1796 Qcow2ReopenState *r; 1797 int ret; 1798 1799 r = g_new0(Qcow2ReopenState, 1); 1800 state->opaque = r; 1801 1802 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1803 state->flags, errp); 1804 if (ret < 0) { 1805 goto fail; 1806 } 1807 1808 /* We need to write out any unwritten data if we reopen read-only. */ 1809 if ((state->flags & BDRV_O_RDWR) == 0) { 1810 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1811 if (ret < 0) { 1812 goto fail; 1813 } 1814 1815 ret = bdrv_flush(state->bs); 1816 if (ret < 0) { 1817 goto fail; 1818 } 1819 1820 ret = qcow2_mark_clean(state->bs); 1821 if (ret < 0) { 1822 goto fail; 1823 } 1824 } 1825 1826 return 0; 1827 1828 fail: 1829 qcow2_update_options_abort(state->bs, r); 1830 g_free(r); 1831 return ret; 1832 } 1833 1834 static void qcow2_reopen_commit(BDRVReopenState *state) 1835 { 1836 qcow2_update_options_commit(state->bs, state->opaque); 1837 g_free(state->opaque); 1838 } 1839 1840 static void qcow2_reopen_abort(BDRVReopenState *state) 1841 { 1842 qcow2_update_options_abort(state->bs, state->opaque); 1843 g_free(state->opaque); 1844 } 1845 1846 static void qcow2_join_options(QDict *options, QDict *old_options) 1847 { 1848 bool has_new_overlap_template = 1849 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1850 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1851 bool has_new_total_cache_size = 1852 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1853 bool has_all_cache_options; 1854 1855 /* New overlap template overrides all old overlap options */ 1856 if (has_new_overlap_template) { 1857 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1858 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1859 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1860 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1861 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1862 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1863 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1864 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1865 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1866 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1867 } 1868 1869 /* New total cache size overrides all old options */ 1870 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1871 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1872 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1873 } 1874 1875 qdict_join(options, old_options, false); 1876 1877 /* 1878 * If after merging all cache size options are set, an old total size is 1879 * overwritten. Do keep all options, however, if all three are new. The 1880 * resulting error message is what we want to happen. 1881 */ 1882 has_all_cache_options = 1883 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1884 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1885 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1886 1887 if (has_all_cache_options && !has_new_total_cache_size) { 1888 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1889 } 1890 } 1891 1892 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, 1893 bool want_zero, 1894 int64_t offset, int64_t count, 1895 int64_t *pnum, int64_t *map, 1896 BlockDriverState **file) 1897 { 1898 BDRVQcow2State *s = bs->opaque; 1899 uint64_t cluster_offset; 1900 int index_in_cluster, ret; 1901 unsigned int bytes; 1902 int status = 0; 1903 1904 if (!s->metadata_preallocation_checked) { 1905 ret = qcow2_detect_metadata_preallocation(bs); 1906 s->metadata_preallocation = (ret == 1); 1907 s->metadata_preallocation_checked = true; 1908 } 1909 1910 bytes = MIN(INT_MAX, count); 1911 qemu_co_mutex_lock(&s->lock); 1912 ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); 1913 qemu_co_mutex_unlock(&s->lock); 1914 if (ret < 0) { 1915 return ret; 1916 } 1917 1918 *pnum = bytes; 1919 1920 if ((ret == QCOW2_CLUSTER_NORMAL || ret == QCOW2_CLUSTER_ZERO_ALLOC) && 1921 !s->crypto) { 1922 index_in_cluster = offset & (s->cluster_size - 1); 1923 *map = cluster_offset | index_in_cluster; 1924 *file = s->data_file->bs; 1925 status |= BDRV_BLOCK_OFFSET_VALID; 1926 } 1927 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1928 status |= BDRV_BLOCK_ZERO; 1929 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1930 status |= BDRV_BLOCK_DATA; 1931 } 1932 if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) && 1933 (status & BDRV_BLOCK_OFFSET_VALID)) 1934 { 1935 status |= BDRV_BLOCK_RECURSE; 1936 } 1937 return status; 1938 } 1939 1940 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, 1941 QCowL2Meta **pl2meta, 1942 bool link_l2) 1943 { 1944 int ret = 0; 1945 QCowL2Meta *l2meta = *pl2meta; 1946 1947 while (l2meta != NULL) { 1948 QCowL2Meta *next; 1949 1950 if (link_l2) { 1951 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1952 if (ret) { 1953 goto out; 1954 } 1955 } else { 1956 qcow2_alloc_cluster_abort(bs, l2meta); 1957 } 1958 1959 /* Take the request off the list of running requests */ 1960 if (l2meta->nb_clusters != 0) { 1961 QLIST_REMOVE(l2meta, next_in_flight); 1962 } 1963 1964 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1965 1966 next = l2meta->next; 1967 g_free(l2meta); 1968 l2meta = next; 1969 } 1970 out: 1971 *pl2meta = l2meta; 1972 return ret; 1973 } 1974 1975 static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs, 1976 uint64_t offset, uint64_t bytes, 1977 QEMUIOVector *qiov, 1978 size_t qiov_offset, int flags) 1979 { 1980 BDRVQcow2State *s = bs->opaque; 1981 int offset_in_cluster; 1982 int ret; 1983 unsigned int cur_bytes; /* number of bytes in current iteration */ 1984 uint64_t cluster_offset = 0; 1985 uint8_t *cluster_data = NULL; 1986 1987 while (bytes != 0) { 1988 1989 /* prepare next request */ 1990 cur_bytes = MIN(bytes, INT_MAX); 1991 if (s->crypto) { 1992 cur_bytes = MIN(cur_bytes, 1993 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1994 } 1995 1996 qemu_co_mutex_lock(&s->lock); 1997 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1998 qemu_co_mutex_unlock(&s->lock); 1999 if (ret < 0) { 2000 goto fail; 2001 } 2002 2003 offset_in_cluster = offset_into_cluster(s, offset); 2004 2005 switch (ret) { 2006 case QCOW2_CLUSTER_UNALLOCATED: 2007 2008 if (bs->backing) { 2009 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 2010 ret = bdrv_co_preadv_part(bs->backing, offset, cur_bytes, 2011 qiov, qiov_offset, 0); 2012 if (ret < 0) { 2013 goto fail; 2014 } 2015 } else { 2016 /* Note: in this case, no need to wait */ 2017 qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes); 2018 } 2019 break; 2020 2021 case QCOW2_CLUSTER_ZERO_PLAIN: 2022 case QCOW2_CLUSTER_ZERO_ALLOC: 2023 qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes); 2024 break; 2025 2026 case QCOW2_CLUSTER_COMPRESSED: 2027 ret = qcow2_co_preadv_compressed(bs, cluster_offset, 2028 offset, cur_bytes, 2029 qiov, qiov_offset); 2030 if (ret < 0) { 2031 goto fail; 2032 } 2033 2034 break; 2035 2036 case QCOW2_CLUSTER_NORMAL: 2037 if ((cluster_offset & 511) != 0) { 2038 ret = -EIO; 2039 goto fail; 2040 } 2041 2042 if (bs->encrypted) { 2043 assert(s->crypto); 2044 2045 /* 2046 * For encrypted images, read everything into a temporary 2047 * contiguous buffer on which the AES functions can work. 2048 */ 2049 if (!cluster_data) { 2050 cluster_data = 2051 qemu_try_blockalign(s->data_file->bs, 2052 QCOW_MAX_CRYPT_CLUSTERS 2053 * s->cluster_size); 2054 if (cluster_data == NULL) { 2055 ret = -ENOMEM; 2056 goto fail; 2057 } 2058 } 2059 2060 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2061 2062 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 2063 ret = bdrv_co_pread(s->data_file, 2064 cluster_offset + offset_in_cluster, 2065 cur_bytes, cluster_data, 0); 2066 if (ret < 0) { 2067 goto fail; 2068 } 2069 2070 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 2071 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 2072 if (qcow2_co_decrypt(bs, cluster_offset, offset, 2073 cluster_data, cur_bytes) < 0) { 2074 ret = -EIO; 2075 goto fail; 2076 } 2077 qemu_iovec_from_buf(qiov, qiov_offset, cluster_data, cur_bytes); 2078 } else { 2079 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 2080 ret = bdrv_co_preadv_part(s->data_file, 2081 cluster_offset + offset_in_cluster, 2082 cur_bytes, qiov, qiov_offset, 0); 2083 if (ret < 0) { 2084 goto fail; 2085 } 2086 } 2087 break; 2088 2089 default: 2090 g_assert_not_reached(); 2091 ret = -EIO; 2092 goto fail; 2093 } 2094 2095 bytes -= cur_bytes; 2096 offset += cur_bytes; 2097 qiov_offset += cur_bytes; 2098 } 2099 ret = 0; 2100 2101 fail: 2102 qemu_vfree(cluster_data); 2103 2104 return ret; 2105 } 2106 2107 /* Check if it's possible to merge a write request with the writing of 2108 * the data from the COW regions */ 2109 static bool merge_cow(uint64_t offset, unsigned bytes, 2110 QEMUIOVector *qiov, size_t qiov_offset, 2111 QCowL2Meta *l2meta) 2112 { 2113 QCowL2Meta *m; 2114 2115 for (m = l2meta; m != NULL; m = m->next) { 2116 /* If both COW regions are empty then there's nothing to merge */ 2117 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 2118 continue; 2119 } 2120 2121 /* If COW regions are handled already, skip this too */ 2122 if (m->skip_cow) { 2123 continue; 2124 } 2125 2126 /* The data (middle) region must be immediately after the 2127 * start region */ 2128 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 2129 continue; 2130 } 2131 2132 /* The end region must be immediately after the data (middle) 2133 * region */ 2134 if (m->offset + m->cow_end.offset != offset + bytes) { 2135 continue; 2136 } 2137 2138 /* Make sure that adding both COW regions to the QEMUIOVector 2139 * does not exceed IOV_MAX */ 2140 if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) { 2141 continue; 2142 } 2143 2144 m->data_qiov = qiov; 2145 m->data_qiov_offset = qiov_offset; 2146 return true; 2147 } 2148 2149 return false; 2150 } 2151 2152 static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes) 2153 { 2154 int64_t nr; 2155 return !bytes || 2156 (!bdrv_is_allocated_above(bs, NULL, false, offset, bytes, &nr) && 2157 nr == bytes); 2158 } 2159 2160 static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m) 2161 { 2162 /* 2163 * This check is designed for optimization shortcut so it must be 2164 * efficient. 2165 * Instead of is_zero(), use is_unallocated() as it is faster (but not 2166 * as accurate and can result in false negatives). 2167 */ 2168 return is_unallocated(bs, m->offset + m->cow_start.offset, 2169 m->cow_start.nb_bytes) && 2170 is_unallocated(bs, m->offset + m->cow_end.offset, 2171 m->cow_end.nb_bytes); 2172 } 2173 2174 static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) 2175 { 2176 BDRVQcow2State *s = bs->opaque; 2177 QCowL2Meta *m; 2178 2179 if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) { 2180 return 0; 2181 } 2182 2183 if (bs->encrypted) { 2184 return 0; 2185 } 2186 2187 for (m = l2meta; m != NULL; m = m->next) { 2188 int ret; 2189 2190 if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) { 2191 continue; 2192 } 2193 2194 if (!is_zero_cow(bs, m)) { 2195 continue; 2196 } 2197 2198 /* 2199 * instead of writing zero COW buffers, 2200 * efficiently zero out the whole clusters 2201 */ 2202 2203 ret = qcow2_pre_write_overlap_check(bs, 0, m->alloc_offset, 2204 m->nb_clusters * s->cluster_size, 2205 true); 2206 if (ret < 0) { 2207 return ret; 2208 } 2209 2210 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE); 2211 ret = bdrv_co_pwrite_zeroes(s->data_file, m->alloc_offset, 2212 m->nb_clusters * s->cluster_size, 2213 BDRV_REQ_NO_FALLBACK); 2214 if (ret < 0) { 2215 if (ret != -ENOTSUP && ret != -EAGAIN) { 2216 return ret; 2217 } 2218 continue; 2219 } 2220 2221 trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters); 2222 m->skip_cow = true; 2223 } 2224 return 0; 2225 } 2226 2227 static coroutine_fn int qcow2_co_pwritev_part( 2228 BlockDriverState *bs, uint64_t offset, uint64_t bytes, 2229 QEMUIOVector *qiov, size_t qiov_offset, int flags) 2230 { 2231 BDRVQcow2State *s = bs->opaque; 2232 int offset_in_cluster; 2233 int ret; 2234 unsigned int cur_bytes; /* number of sectors in current iteration */ 2235 uint64_t cluster_offset; 2236 QEMUIOVector encrypted_qiov; 2237 uint64_t bytes_done = 0; 2238 uint8_t *cluster_data = NULL; 2239 QCowL2Meta *l2meta = NULL; 2240 2241 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 2242 2243 qemu_co_mutex_lock(&s->lock); 2244 2245 while (bytes != 0) { 2246 2247 l2meta = NULL; 2248 2249 trace_qcow2_writev_start_part(qemu_coroutine_self()); 2250 offset_in_cluster = offset_into_cluster(s, offset); 2251 cur_bytes = MIN(bytes, INT_MAX); 2252 if (bs->encrypted) { 2253 cur_bytes = MIN(cur_bytes, 2254 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 2255 - offset_in_cluster); 2256 } 2257 2258 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2259 &cluster_offset, &l2meta); 2260 if (ret < 0) { 2261 goto out_locked; 2262 } 2263 2264 assert((cluster_offset & 511) == 0); 2265 2266 ret = qcow2_pre_write_overlap_check(bs, 0, 2267 cluster_offset + offset_in_cluster, 2268 cur_bytes, true); 2269 if (ret < 0) { 2270 goto out_locked; 2271 } 2272 2273 qemu_co_mutex_unlock(&s->lock); 2274 2275 if (bs->encrypted) { 2276 assert(s->crypto); 2277 if (!cluster_data) { 2278 cluster_data = qemu_try_blockalign(bs->file->bs, 2279 QCOW_MAX_CRYPT_CLUSTERS 2280 * s->cluster_size); 2281 if (cluster_data == NULL) { 2282 ret = -ENOMEM; 2283 goto out_unlocked; 2284 } 2285 } 2286 2287 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2288 qemu_iovec_to_buf(qiov, qiov_offset + bytes_done, 2289 cluster_data, cur_bytes); 2290 2291 if (qcow2_co_encrypt(bs, cluster_offset, offset, 2292 cluster_data, cur_bytes) < 0) { 2293 ret = -EIO; 2294 goto out_unlocked; 2295 } 2296 2297 qemu_iovec_init_buf(&encrypted_qiov, cluster_data, cur_bytes); 2298 } 2299 2300 /* Try to efficiently initialize the physical space with zeroes */ 2301 ret = handle_alloc_space(bs, l2meta); 2302 if (ret < 0) { 2303 goto out_unlocked; 2304 } 2305 2306 /* If we need to do COW, check if it's possible to merge the 2307 * writing of the guest data together with that of the COW regions. 2308 * If it's not possible (or not necessary) then write the 2309 * guest data now. */ 2310 if (!merge_cow(offset, cur_bytes, 2311 bs->encrypted ? &encrypted_qiov : qiov, 2312 bs->encrypted ? 0 : qiov_offset + bytes_done, l2meta)) 2313 { 2314 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 2315 trace_qcow2_writev_data(qemu_coroutine_self(), 2316 cluster_offset + offset_in_cluster); 2317 ret = bdrv_co_pwritev_part( 2318 s->data_file, cluster_offset + offset_in_cluster, cur_bytes, 2319 bs->encrypted ? &encrypted_qiov : qiov, 2320 bs->encrypted ? 0 : qiov_offset + bytes_done, 0); 2321 if (ret < 0) { 2322 goto out_unlocked; 2323 } 2324 } 2325 2326 qemu_co_mutex_lock(&s->lock); 2327 2328 ret = qcow2_handle_l2meta(bs, &l2meta, true); 2329 if (ret) { 2330 goto out_locked; 2331 } 2332 2333 bytes -= cur_bytes; 2334 offset += cur_bytes; 2335 bytes_done += cur_bytes; 2336 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2337 } 2338 ret = 0; 2339 goto out_locked; 2340 2341 out_unlocked: 2342 qemu_co_mutex_lock(&s->lock); 2343 2344 out_locked: 2345 qcow2_handle_l2meta(bs, &l2meta, false); 2346 2347 qemu_co_mutex_unlock(&s->lock); 2348 2349 qemu_vfree(cluster_data); 2350 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2351 2352 return ret; 2353 } 2354 2355 static int qcow2_inactivate(BlockDriverState *bs) 2356 { 2357 BDRVQcow2State *s = bs->opaque; 2358 int ret, result = 0; 2359 Error *local_err = NULL; 2360 2361 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2362 if (local_err != NULL) { 2363 result = -EINVAL; 2364 error_reportf_err(local_err, "Lost persistent bitmaps during " 2365 "inactivation of node '%s': ", 2366 bdrv_get_device_or_node_name(bs)); 2367 } 2368 2369 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2370 if (ret) { 2371 result = ret; 2372 error_report("Failed to flush the L2 table cache: %s", 2373 strerror(-ret)); 2374 } 2375 2376 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2377 if (ret) { 2378 result = ret; 2379 error_report("Failed to flush the refcount block cache: %s", 2380 strerror(-ret)); 2381 } 2382 2383 if (result == 0) { 2384 qcow2_mark_clean(bs); 2385 } 2386 2387 return result; 2388 } 2389 2390 static void qcow2_close(BlockDriverState *bs) 2391 { 2392 BDRVQcow2State *s = bs->opaque; 2393 qemu_vfree(s->l1_table); 2394 /* else pre-write overlap checks in cache_destroy may crash */ 2395 s->l1_table = NULL; 2396 2397 if (!(s->flags & BDRV_O_INACTIVE)) { 2398 qcow2_inactivate(bs); 2399 } 2400 2401 cache_clean_timer_del(bs); 2402 qcow2_cache_destroy(s->l2_table_cache); 2403 qcow2_cache_destroy(s->refcount_block_cache); 2404 2405 qcrypto_block_free(s->crypto); 2406 s->crypto = NULL; 2407 2408 g_free(s->unknown_header_fields); 2409 cleanup_unknown_header_ext(bs); 2410 2411 g_free(s->image_data_file); 2412 g_free(s->image_backing_file); 2413 g_free(s->image_backing_format); 2414 2415 if (has_data_file(bs)) { 2416 bdrv_unref_child(bs, s->data_file); 2417 } 2418 2419 qcow2_refcount_close(bs); 2420 qcow2_free_snapshots(bs); 2421 } 2422 2423 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, 2424 Error **errp) 2425 { 2426 BDRVQcow2State *s = bs->opaque; 2427 int flags = s->flags; 2428 QCryptoBlock *crypto = NULL; 2429 QDict *options; 2430 Error *local_err = NULL; 2431 int ret; 2432 2433 /* 2434 * Backing files are read-only which makes all of their metadata immutable, 2435 * that means we don't have to worry about reopening them here. 2436 */ 2437 2438 crypto = s->crypto; 2439 s->crypto = NULL; 2440 2441 qcow2_close(bs); 2442 2443 memset(s, 0, sizeof(BDRVQcow2State)); 2444 options = qdict_clone_shallow(bs->options); 2445 2446 flags &= ~BDRV_O_INACTIVE; 2447 qemu_co_mutex_lock(&s->lock); 2448 ret = qcow2_do_open(bs, options, flags, &local_err); 2449 qemu_co_mutex_unlock(&s->lock); 2450 qobject_unref(options); 2451 if (local_err) { 2452 error_propagate_prepend(errp, local_err, 2453 "Could not reopen qcow2 layer: "); 2454 bs->drv = NULL; 2455 return; 2456 } else if (ret < 0) { 2457 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2458 bs->drv = NULL; 2459 return; 2460 } 2461 2462 s->crypto = crypto; 2463 } 2464 2465 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2466 size_t len, size_t buflen) 2467 { 2468 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2469 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2470 2471 if (buflen < ext_len) { 2472 return -ENOSPC; 2473 } 2474 2475 *ext_backing_fmt = (QCowExtension) { 2476 .magic = cpu_to_be32(magic), 2477 .len = cpu_to_be32(len), 2478 }; 2479 2480 if (len) { 2481 memcpy(buf + sizeof(QCowExtension), s, len); 2482 } 2483 2484 return ext_len; 2485 } 2486 2487 /* 2488 * Updates the qcow2 header, including the variable length parts of it, i.e. 2489 * the backing file name and all extensions. qcow2 was not designed to allow 2490 * such changes, so if we run out of space (we can only use the first cluster) 2491 * this function may fail. 2492 * 2493 * Returns 0 on success, -errno in error cases. 2494 */ 2495 int qcow2_update_header(BlockDriverState *bs) 2496 { 2497 BDRVQcow2State *s = bs->opaque; 2498 QCowHeader *header; 2499 char *buf; 2500 size_t buflen = s->cluster_size; 2501 int ret; 2502 uint64_t total_size; 2503 uint32_t refcount_table_clusters; 2504 size_t header_length; 2505 Qcow2UnknownHeaderExtension *uext; 2506 2507 buf = qemu_blockalign(bs, buflen); 2508 2509 /* Header structure */ 2510 header = (QCowHeader*) buf; 2511 2512 if (buflen < sizeof(*header)) { 2513 ret = -ENOSPC; 2514 goto fail; 2515 } 2516 2517 header_length = sizeof(*header) + s->unknown_header_fields_size; 2518 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2519 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2520 2521 *header = (QCowHeader) { 2522 /* Version 2 fields */ 2523 .magic = cpu_to_be32(QCOW_MAGIC), 2524 .version = cpu_to_be32(s->qcow_version), 2525 .backing_file_offset = 0, 2526 .backing_file_size = 0, 2527 .cluster_bits = cpu_to_be32(s->cluster_bits), 2528 .size = cpu_to_be64(total_size), 2529 .crypt_method = cpu_to_be32(s->crypt_method_header), 2530 .l1_size = cpu_to_be32(s->l1_size), 2531 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2532 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2533 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2534 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2535 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2536 2537 /* Version 3 fields */ 2538 .incompatible_features = cpu_to_be64(s->incompatible_features), 2539 .compatible_features = cpu_to_be64(s->compatible_features), 2540 .autoclear_features = cpu_to_be64(s->autoclear_features), 2541 .refcount_order = cpu_to_be32(s->refcount_order), 2542 .header_length = cpu_to_be32(header_length), 2543 }; 2544 2545 /* For older versions, write a shorter header */ 2546 switch (s->qcow_version) { 2547 case 2: 2548 ret = offsetof(QCowHeader, incompatible_features); 2549 break; 2550 case 3: 2551 ret = sizeof(*header); 2552 break; 2553 default: 2554 ret = -EINVAL; 2555 goto fail; 2556 } 2557 2558 buf += ret; 2559 buflen -= ret; 2560 memset(buf, 0, buflen); 2561 2562 /* Preserve any unknown field in the header */ 2563 if (s->unknown_header_fields_size) { 2564 if (buflen < s->unknown_header_fields_size) { 2565 ret = -ENOSPC; 2566 goto fail; 2567 } 2568 2569 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2570 buf += s->unknown_header_fields_size; 2571 buflen -= s->unknown_header_fields_size; 2572 } 2573 2574 /* Backing file format header extension */ 2575 if (s->image_backing_format) { 2576 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2577 s->image_backing_format, 2578 strlen(s->image_backing_format), 2579 buflen); 2580 if (ret < 0) { 2581 goto fail; 2582 } 2583 2584 buf += ret; 2585 buflen -= ret; 2586 } 2587 2588 /* External data file header extension */ 2589 if (has_data_file(bs) && s->image_data_file) { 2590 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE, 2591 s->image_data_file, strlen(s->image_data_file), 2592 buflen); 2593 if (ret < 0) { 2594 goto fail; 2595 } 2596 2597 buf += ret; 2598 buflen -= ret; 2599 } 2600 2601 /* Full disk encryption header pointer extension */ 2602 if (s->crypto_header.offset != 0) { 2603 s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset); 2604 s->crypto_header.length = cpu_to_be64(s->crypto_header.length); 2605 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2606 &s->crypto_header, sizeof(s->crypto_header), 2607 buflen); 2608 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 2609 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 2610 if (ret < 0) { 2611 goto fail; 2612 } 2613 buf += ret; 2614 buflen -= ret; 2615 } 2616 2617 /* Feature table */ 2618 if (s->qcow_version >= 3) { 2619 Qcow2Feature features[] = { 2620 { 2621 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2622 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2623 .name = "dirty bit", 2624 }, 2625 { 2626 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2627 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2628 .name = "corrupt bit", 2629 }, 2630 { 2631 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2632 .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR, 2633 .name = "external data file", 2634 }, 2635 { 2636 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2637 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2638 .name = "lazy refcounts", 2639 }, 2640 }; 2641 2642 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2643 features, sizeof(features), buflen); 2644 if (ret < 0) { 2645 goto fail; 2646 } 2647 buf += ret; 2648 buflen -= ret; 2649 } 2650 2651 /* Bitmap extension */ 2652 if (s->nb_bitmaps > 0) { 2653 Qcow2BitmapHeaderExt bitmaps_header = { 2654 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2655 .bitmap_directory_size = 2656 cpu_to_be64(s->bitmap_directory_size), 2657 .bitmap_directory_offset = 2658 cpu_to_be64(s->bitmap_directory_offset) 2659 }; 2660 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2661 &bitmaps_header, sizeof(bitmaps_header), 2662 buflen); 2663 if (ret < 0) { 2664 goto fail; 2665 } 2666 buf += ret; 2667 buflen -= ret; 2668 } 2669 2670 /* Keep unknown header extensions */ 2671 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2672 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2673 if (ret < 0) { 2674 goto fail; 2675 } 2676 2677 buf += ret; 2678 buflen -= ret; 2679 } 2680 2681 /* End of header extensions */ 2682 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2683 if (ret < 0) { 2684 goto fail; 2685 } 2686 2687 buf += ret; 2688 buflen -= ret; 2689 2690 /* Backing file name */ 2691 if (s->image_backing_file) { 2692 size_t backing_file_len = strlen(s->image_backing_file); 2693 2694 if (buflen < backing_file_len) { 2695 ret = -ENOSPC; 2696 goto fail; 2697 } 2698 2699 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2700 strncpy(buf, s->image_backing_file, buflen); 2701 2702 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2703 header->backing_file_size = cpu_to_be32(backing_file_len); 2704 } 2705 2706 /* Write the new header */ 2707 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2708 if (ret < 0) { 2709 goto fail; 2710 } 2711 2712 ret = 0; 2713 fail: 2714 qemu_vfree(header); 2715 return ret; 2716 } 2717 2718 static int qcow2_change_backing_file(BlockDriverState *bs, 2719 const char *backing_file, const char *backing_fmt) 2720 { 2721 BDRVQcow2State *s = bs->opaque; 2722 2723 /* Adding a backing file means that the external data file alone won't be 2724 * enough to make sense of the content */ 2725 if (backing_file && data_file_is_raw(bs)) { 2726 return -EINVAL; 2727 } 2728 2729 if (backing_file && strlen(backing_file) > 1023) { 2730 return -EINVAL; 2731 } 2732 2733 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), 2734 backing_file ?: ""); 2735 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2736 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2737 2738 g_free(s->image_backing_file); 2739 g_free(s->image_backing_format); 2740 2741 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2742 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2743 2744 return qcow2_update_header(bs); 2745 } 2746 2747 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2748 { 2749 if (g_str_equal(encryptfmt, "luks")) { 2750 return QCOW_CRYPT_LUKS; 2751 } else if (g_str_equal(encryptfmt, "aes")) { 2752 return QCOW_CRYPT_AES; 2753 } else { 2754 return -EINVAL; 2755 } 2756 } 2757 2758 static int qcow2_set_up_encryption(BlockDriverState *bs, 2759 QCryptoBlockCreateOptions *cryptoopts, 2760 Error **errp) 2761 { 2762 BDRVQcow2State *s = bs->opaque; 2763 QCryptoBlock *crypto = NULL; 2764 int fmt, ret; 2765 2766 switch (cryptoopts->format) { 2767 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 2768 fmt = QCOW_CRYPT_LUKS; 2769 break; 2770 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 2771 fmt = QCOW_CRYPT_AES; 2772 break; 2773 default: 2774 error_setg(errp, "Crypto format not supported in qcow2"); 2775 return -EINVAL; 2776 } 2777 2778 s->crypt_method_header = fmt; 2779 2780 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2781 qcow2_crypto_hdr_init_func, 2782 qcow2_crypto_hdr_write_func, 2783 bs, errp); 2784 if (!crypto) { 2785 return -EINVAL; 2786 } 2787 2788 ret = qcow2_update_header(bs); 2789 if (ret < 0) { 2790 error_setg_errno(errp, -ret, "Could not write encryption header"); 2791 goto out; 2792 } 2793 2794 ret = 0; 2795 out: 2796 qcrypto_block_free(crypto); 2797 return ret; 2798 } 2799 2800 /** 2801 * Preallocates metadata structures for data clusters between @offset (in the 2802 * guest disk) and @new_length (which is thus generally the new guest disk 2803 * size). 2804 * 2805 * Returns: 0 on success, -errno on failure. 2806 */ 2807 static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, 2808 uint64_t new_length, PreallocMode mode, 2809 Error **errp) 2810 { 2811 BDRVQcow2State *s = bs->opaque; 2812 uint64_t bytes; 2813 uint64_t host_offset = 0; 2814 int64_t file_length; 2815 unsigned int cur_bytes; 2816 int ret; 2817 QCowL2Meta *meta; 2818 2819 assert(offset <= new_length); 2820 bytes = new_length - offset; 2821 2822 while (bytes) { 2823 cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size)); 2824 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2825 &host_offset, &meta); 2826 if (ret < 0) { 2827 error_setg_errno(errp, -ret, "Allocating clusters failed"); 2828 return ret; 2829 } 2830 2831 while (meta) { 2832 QCowL2Meta *next = meta->next; 2833 2834 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2835 if (ret < 0) { 2836 error_setg_errno(errp, -ret, "Mapping clusters failed"); 2837 qcow2_free_any_clusters(bs, meta->alloc_offset, 2838 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2839 return ret; 2840 } 2841 2842 /* There are no dependent requests, but we need to remove our 2843 * request from the list of in-flight requests */ 2844 QLIST_REMOVE(meta, next_in_flight); 2845 2846 g_free(meta); 2847 meta = next; 2848 } 2849 2850 /* TODO Preallocate data if requested */ 2851 2852 bytes -= cur_bytes; 2853 offset += cur_bytes; 2854 } 2855 2856 /* 2857 * It is expected that the image file is large enough to actually contain 2858 * all of the allocated clusters (otherwise we get failing reads after 2859 * EOF). Extend the image to the last allocated sector. 2860 */ 2861 file_length = bdrv_getlength(s->data_file->bs); 2862 if (file_length < 0) { 2863 error_setg_errno(errp, -file_length, "Could not get file size"); 2864 return file_length; 2865 } 2866 2867 if (host_offset + cur_bytes > file_length) { 2868 if (mode == PREALLOC_MODE_METADATA) { 2869 mode = PREALLOC_MODE_OFF; 2870 } 2871 ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, mode, 2872 errp); 2873 if (ret < 0) { 2874 return ret; 2875 } 2876 } 2877 2878 return 0; 2879 } 2880 2881 /* qcow2_refcount_metadata_size: 2882 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2883 * @cluster_size: size of a cluster, in bytes 2884 * @refcount_order: refcount bits power-of-2 exponent 2885 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2886 * needs to be 2887 * 2888 * Returns: Number of bytes required for refcount blocks and table metadata. 2889 */ 2890 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2891 int refcount_order, bool generous_increase, 2892 uint64_t *refblock_count) 2893 { 2894 /* 2895 * Every host cluster is reference-counted, including metadata (even 2896 * refcount metadata is recursively included). 2897 * 2898 * An accurate formula for the size of refcount metadata size is difficult 2899 * to derive. An easier method of calculation is finding the fixed point 2900 * where no further refcount blocks or table clusters are required to 2901 * reference count every cluster. 2902 */ 2903 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2904 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2905 int64_t table = 0; /* number of refcount table clusters */ 2906 int64_t blocks = 0; /* number of refcount block clusters */ 2907 int64_t last; 2908 int64_t n = 0; 2909 2910 do { 2911 last = n; 2912 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2913 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2914 n = clusters + blocks + table; 2915 2916 if (n == last && generous_increase) { 2917 clusters += DIV_ROUND_UP(table, 2); 2918 n = 0; /* force another loop */ 2919 generous_increase = false; 2920 } 2921 } while (n != last); 2922 2923 if (refblock_count) { 2924 *refblock_count = blocks; 2925 } 2926 2927 return (blocks + table) * cluster_size; 2928 } 2929 2930 /** 2931 * qcow2_calc_prealloc_size: 2932 * @total_size: virtual disk size in bytes 2933 * @cluster_size: cluster size in bytes 2934 * @refcount_order: refcount bits power-of-2 exponent 2935 * 2936 * Returns: Total number of bytes required for the fully allocated image 2937 * (including metadata). 2938 */ 2939 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2940 size_t cluster_size, 2941 int refcount_order) 2942 { 2943 int64_t meta_size = 0; 2944 uint64_t nl1e, nl2e; 2945 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); 2946 2947 /* header: 1 cluster */ 2948 meta_size += cluster_size; 2949 2950 /* total size of L2 tables */ 2951 nl2e = aligned_total_size / cluster_size; 2952 nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t)); 2953 meta_size += nl2e * sizeof(uint64_t); 2954 2955 /* total size of L1 tables */ 2956 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2957 nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t)); 2958 meta_size += nl1e * sizeof(uint64_t); 2959 2960 /* total size of refcount table and blocks */ 2961 meta_size += qcow2_refcount_metadata_size( 2962 (meta_size + aligned_total_size) / cluster_size, 2963 cluster_size, refcount_order, false, NULL); 2964 2965 return meta_size + aligned_total_size; 2966 } 2967 2968 static bool validate_cluster_size(size_t cluster_size, Error **errp) 2969 { 2970 int cluster_bits = ctz32(cluster_size); 2971 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2972 (1 << cluster_bits) != cluster_size) 2973 { 2974 error_setg(errp, "Cluster size must be a power of two between %d and " 2975 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2976 return false; 2977 } 2978 return true; 2979 } 2980 2981 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2982 { 2983 size_t cluster_size; 2984 2985 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2986 DEFAULT_CLUSTER_SIZE); 2987 if (!validate_cluster_size(cluster_size, errp)) { 2988 return 0; 2989 } 2990 return cluster_size; 2991 } 2992 2993 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2994 { 2995 char *buf; 2996 int ret; 2997 2998 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2999 if (!buf) { 3000 ret = 3; /* default */ 3001 } else if (!strcmp(buf, "0.10")) { 3002 ret = 2; 3003 } else if (!strcmp(buf, "1.1")) { 3004 ret = 3; 3005 } else { 3006 error_setg(errp, "Invalid compatibility level: '%s'", buf); 3007 ret = -EINVAL; 3008 } 3009 g_free(buf); 3010 return ret; 3011 } 3012 3013 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 3014 Error **errp) 3015 { 3016 uint64_t refcount_bits; 3017 3018 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 3019 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 3020 error_setg(errp, "Refcount width must be a power of two and may not " 3021 "exceed 64 bits"); 3022 return 0; 3023 } 3024 3025 if (version < 3 && refcount_bits != 16) { 3026 error_setg(errp, "Different refcount widths than 16 bits require " 3027 "compatibility level 1.1 or above (use compat=1.1 or " 3028 "greater)"); 3029 return 0; 3030 } 3031 3032 return refcount_bits; 3033 } 3034 3035 static int coroutine_fn 3036 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 3037 { 3038 BlockdevCreateOptionsQcow2 *qcow2_opts; 3039 QDict *options; 3040 3041 /* 3042 * Open the image file and write a minimal qcow2 header. 3043 * 3044 * We keep things simple and start with a zero-sized image. We also 3045 * do without refcount blocks or a L1 table for now. We'll fix the 3046 * inconsistency later. 3047 * 3048 * We do need a refcount table because growing the refcount table means 3049 * allocating two new refcount blocks - the seconds of which would be at 3050 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 3051 * size for any qcow2 image. 3052 */ 3053 BlockBackend *blk = NULL; 3054 BlockDriverState *bs = NULL; 3055 BlockDriverState *data_bs = NULL; 3056 QCowHeader *header; 3057 size_t cluster_size; 3058 int version; 3059 int refcount_order; 3060 uint64_t* refcount_table; 3061 Error *local_err = NULL; 3062 int ret; 3063 3064 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); 3065 qcow2_opts = &create_options->u.qcow2; 3066 3067 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); 3068 if (bs == NULL) { 3069 return -EIO; 3070 } 3071 3072 /* Validate options and set default values */ 3073 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { 3074 error_setg(errp, "Image size must be a multiple of 512 bytes"); 3075 ret = -EINVAL; 3076 goto out; 3077 } 3078 3079 if (qcow2_opts->has_version) { 3080 switch (qcow2_opts->version) { 3081 case BLOCKDEV_QCOW2_VERSION_V2: 3082 version = 2; 3083 break; 3084 case BLOCKDEV_QCOW2_VERSION_V3: 3085 version = 3; 3086 break; 3087 default: 3088 g_assert_not_reached(); 3089 } 3090 } else { 3091 version = 3; 3092 } 3093 3094 if (qcow2_opts->has_cluster_size) { 3095 cluster_size = qcow2_opts->cluster_size; 3096 } else { 3097 cluster_size = DEFAULT_CLUSTER_SIZE; 3098 } 3099 3100 if (!validate_cluster_size(cluster_size, errp)) { 3101 ret = -EINVAL; 3102 goto out; 3103 } 3104 3105 if (!qcow2_opts->has_preallocation) { 3106 qcow2_opts->preallocation = PREALLOC_MODE_OFF; 3107 } 3108 if (qcow2_opts->has_backing_file && 3109 qcow2_opts->preallocation != PREALLOC_MODE_OFF) 3110 { 3111 error_setg(errp, "Backing file and preallocation cannot be used at " 3112 "the same time"); 3113 ret = -EINVAL; 3114 goto out; 3115 } 3116 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { 3117 error_setg(errp, "Backing format cannot be used without backing file"); 3118 ret = -EINVAL; 3119 goto out; 3120 } 3121 3122 if (!qcow2_opts->has_lazy_refcounts) { 3123 qcow2_opts->lazy_refcounts = false; 3124 } 3125 if (version < 3 && qcow2_opts->lazy_refcounts) { 3126 error_setg(errp, "Lazy refcounts only supported with compatibility " 3127 "level 1.1 and above (use version=v3 or greater)"); 3128 ret = -EINVAL; 3129 goto out; 3130 } 3131 3132 if (!qcow2_opts->has_refcount_bits) { 3133 qcow2_opts->refcount_bits = 16; 3134 } 3135 if (qcow2_opts->refcount_bits > 64 || 3136 !is_power_of_2(qcow2_opts->refcount_bits)) 3137 { 3138 error_setg(errp, "Refcount width must be a power of two and may not " 3139 "exceed 64 bits"); 3140 ret = -EINVAL; 3141 goto out; 3142 } 3143 if (version < 3 && qcow2_opts->refcount_bits != 16) { 3144 error_setg(errp, "Different refcount widths than 16 bits require " 3145 "compatibility level 1.1 or above (use version=v3 or " 3146 "greater)"); 3147 ret = -EINVAL; 3148 goto out; 3149 } 3150 refcount_order = ctz32(qcow2_opts->refcount_bits); 3151 3152 if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) { 3153 error_setg(errp, "data-file-raw requires data-file"); 3154 ret = -EINVAL; 3155 goto out; 3156 } 3157 if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) { 3158 error_setg(errp, "Backing file and data-file-raw cannot be used at " 3159 "the same time"); 3160 ret = -EINVAL; 3161 goto out; 3162 } 3163 3164 if (qcow2_opts->data_file) { 3165 if (version < 3) { 3166 error_setg(errp, "External data files are only supported with " 3167 "compatibility level 1.1 and above (use version=v3 or " 3168 "greater)"); 3169 ret = -EINVAL; 3170 goto out; 3171 } 3172 data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp); 3173 if (data_bs == NULL) { 3174 ret = -EIO; 3175 goto out; 3176 } 3177 } 3178 3179 /* Create BlockBackend to write to the image */ 3180 blk = blk_new(bdrv_get_aio_context(bs), 3181 BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 3182 ret = blk_insert_bs(blk, bs, errp); 3183 if (ret < 0) { 3184 goto out; 3185 } 3186 blk_set_allow_write_beyond_eof(blk, true); 3187 3188 /* Clear the protocol layer and preallocate it if necessary */ 3189 ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); 3190 if (ret < 0) { 3191 goto out; 3192 } 3193 3194 /* Write the header */ 3195 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 3196 header = g_malloc0(cluster_size); 3197 *header = (QCowHeader) { 3198 .magic = cpu_to_be32(QCOW_MAGIC), 3199 .version = cpu_to_be32(version), 3200 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 3201 .size = cpu_to_be64(0), 3202 .l1_table_offset = cpu_to_be64(0), 3203 .l1_size = cpu_to_be32(0), 3204 .refcount_table_offset = cpu_to_be64(cluster_size), 3205 .refcount_table_clusters = cpu_to_be32(1), 3206 .refcount_order = cpu_to_be32(refcount_order), 3207 .header_length = cpu_to_be32(sizeof(*header)), 3208 }; 3209 3210 /* We'll update this to correct value later */ 3211 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 3212 3213 if (qcow2_opts->lazy_refcounts) { 3214 header->compatible_features |= 3215 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 3216 } 3217 if (data_bs) { 3218 header->incompatible_features |= 3219 cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE); 3220 } 3221 if (qcow2_opts->data_file_raw) { 3222 header->autoclear_features |= 3223 cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW); 3224 } 3225 3226 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 3227 g_free(header); 3228 if (ret < 0) { 3229 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 3230 goto out; 3231 } 3232 3233 /* Write a refcount table with one refcount block */ 3234 refcount_table = g_malloc0(2 * cluster_size); 3235 refcount_table[0] = cpu_to_be64(2 * cluster_size); 3236 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 3237 g_free(refcount_table); 3238 3239 if (ret < 0) { 3240 error_setg_errno(errp, -ret, "Could not write refcount table"); 3241 goto out; 3242 } 3243 3244 blk_unref(blk); 3245 blk = NULL; 3246 3247 /* 3248 * And now open the image and make it consistent first (i.e. increase the 3249 * refcount of the cluster that is occupied by the header and the refcount 3250 * table) 3251 */ 3252 options = qdict_new(); 3253 qdict_put_str(options, "driver", "qcow2"); 3254 qdict_put_str(options, "file", bs->node_name); 3255 if (data_bs) { 3256 qdict_put_str(options, "data-file", data_bs->node_name); 3257 } 3258 blk = blk_new_open(NULL, NULL, options, 3259 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 3260 &local_err); 3261 if (blk == NULL) { 3262 error_propagate(errp, local_err); 3263 ret = -EIO; 3264 goto out; 3265 } 3266 3267 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 3268 if (ret < 0) { 3269 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 3270 "header and refcount table"); 3271 goto out; 3272 3273 } else if (ret != 0) { 3274 error_report("Huh, first cluster in empty image is already in use?"); 3275 abort(); 3276 } 3277 3278 /* Set the external data file if necessary */ 3279 if (data_bs) { 3280 BDRVQcow2State *s = blk_bs(blk)->opaque; 3281 s->image_data_file = g_strdup(data_bs->filename); 3282 } 3283 3284 /* Create a full header (including things like feature table) */ 3285 ret = qcow2_update_header(blk_bs(blk)); 3286 if (ret < 0) { 3287 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 3288 goto out; 3289 } 3290 3291 /* Okay, now that we have a valid image, let's give it the right size */ 3292 ret = blk_truncate(blk, qcow2_opts->size, qcow2_opts->preallocation, errp); 3293 if (ret < 0) { 3294 error_prepend(errp, "Could not resize image: "); 3295 goto out; 3296 } 3297 3298 /* Want a backing file? There you go.*/ 3299 if (qcow2_opts->has_backing_file) { 3300 const char *backing_format = NULL; 3301 3302 if (qcow2_opts->has_backing_fmt) { 3303 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); 3304 } 3305 3306 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, 3307 backing_format); 3308 if (ret < 0) { 3309 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 3310 "with format '%s'", qcow2_opts->backing_file, 3311 backing_format); 3312 goto out; 3313 } 3314 } 3315 3316 /* Want encryption? There you go. */ 3317 if (qcow2_opts->has_encrypt) { 3318 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); 3319 if (ret < 0) { 3320 goto out; 3321 } 3322 } 3323 3324 blk_unref(blk); 3325 blk = NULL; 3326 3327 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 3328 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 3329 * have to setup decryption context. We're not doing any I/O on the top 3330 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 3331 * not have effect. 3332 */ 3333 options = qdict_new(); 3334 qdict_put_str(options, "driver", "qcow2"); 3335 qdict_put_str(options, "file", bs->node_name); 3336 if (data_bs) { 3337 qdict_put_str(options, "data-file", data_bs->node_name); 3338 } 3339 blk = blk_new_open(NULL, NULL, options, 3340 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 3341 &local_err); 3342 if (blk == NULL) { 3343 error_propagate(errp, local_err); 3344 ret = -EIO; 3345 goto out; 3346 } 3347 3348 ret = 0; 3349 out: 3350 blk_unref(blk); 3351 bdrv_unref(bs); 3352 bdrv_unref(data_bs); 3353 return ret; 3354 } 3355 3356 static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts, 3357 Error **errp) 3358 { 3359 BlockdevCreateOptions *create_options = NULL; 3360 QDict *qdict; 3361 Visitor *v; 3362 BlockDriverState *bs = NULL; 3363 BlockDriverState *data_bs = NULL; 3364 Error *local_err = NULL; 3365 const char *val; 3366 int ret; 3367 3368 /* Only the keyval visitor supports the dotted syntax needed for 3369 * encryption, so go through a QDict before getting a QAPI type. Ignore 3370 * options meant for the protocol layer so that the visitor doesn't 3371 * complain. */ 3372 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, 3373 true); 3374 3375 /* Handle encryption options */ 3376 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 3377 if (val && !strcmp(val, "on")) { 3378 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 3379 } else if (val && !strcmp(val, "off")) { 3380 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 3381 } 3382 3383 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 3384 if (val && !strcmp(val, "aes")) { 3385 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 3386 } 3387 3388 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into 3389 * version=v2/v3 below. */ 3390 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); 3391 if (val && !strcmp(val, "0.10")) { 3392 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); 3393 } else if (val && !strcmp(val, "1.1")) { 3394 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); 3395 } 3396 3397 /* Change legacy command line options into QMP ones */ 3398 static const QDictRenames opt_renames[] = { 3399 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 3400 { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, 3401 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, 3402 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, 3403 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, 3404 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 3405 { BLOCK_OPT_COMPAT_LEVEL, "version" }, 3406 { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" }, 3407 { NULL, NULL }, 3408 }; 3409 3410 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 3411 ret = -EINVAL; 3412 goto finish; 3413 } 3414 3415 /* Create and open the file (protocol layer) */ 3416 ret = bdrv_create_file(filename, opts, errp); 3417 if (ret < 0) { 3418 goto finish; 3419 } 3420 3421 bs = bdrv_open(filename, NULL, NULL, 3422 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 3423 if (bs == NULL) { 3424 ret = -EIO; 3425 goto finish; 3426 } 3427 3428 /* Create and open an external data file (protocol layer) */ 3429 val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE); 3430 if (val) { 3431 ret = bdrv_create_file(val, opts, errp); 3432 if (ret < 0) { 3433 goto finish; 3434 } 3435 3436 data_bs = bdrv_open(val, NULL, NULL, 3437 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 3438 errp); 3439 if (data_bs == NULL) { 3440 ret = -EIO; 3441 goto finish; 3442 } 3443 3444 qdict_del(qdict, BLOCK_OPT_DATA_FILE); 3445 qdict_put_str(qdict, "data-file", data_bs->node_name); 3446 } 3447 3448 /* Set 'driver' and 'node' options */ 3449 qdict_put_str(qdict, "driver", "qcow2"); 3450 qdict_put_str(qdict, "file", bs->node_name); 3451 3452 /* Now get the QAPI type BlockdevCreateOptions */ 3453 v = qobject_input_visitor_new_flat_confused(qdict, errp); 3454 if (!v) { 3455 ret = -EINVAL; 3456 goto finish; 3457 } 3458 3459 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 3460 visit_free(v); 3461 3462 if (local_err) { 3463 error_propagate(errp, local_err); 3464 ret = -EINVAL; 3465 goto finish; 3466 } 3467 3468 /* Silently round up size */ 3469 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, 3470 BDRV_SECTOR_SIZE); 3471 3472 /* Create the qcow2 image (format layer) */ 3473 ret = qcow2_co_create(create_options, errp); 3474 if (ret < 0) { 3475 goto finish; 3476 } 3477 3478 ret = 0; 3479 finish: 3480 qobject_unref(qdict); 3481 bdrv_unref(bs); 3482 bdrv_unref(data_bs); 3483 qapi_free_BlockdevCreateOptions(create_options); 3484 return ret; 3485 } 3486 3487 3488 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3489 { 3490 int64_t nr; 3491 int res; 3492 3493 /* Clamp to image length, before checking status of underlying sectors */ 3494 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3495 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3496 } 3497 3498 if (!bytes) { 3499 return true; 3500 } 3501 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3502 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3503 } 3504 3505 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3506 int64_t offset, int bytes, BdrvRequestFlags flags) 3507 { 3508 int ret; 3509 BDRVQcow2State *s = bs->opaque; 3510 3511 uint32_t head = offset % s->cluster_size; 3512 uint32_t tail = (offset + bytes) % s->cluster_size; 3513 3514 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3515 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3516 tail = 0; 3517 } 3518 3519 if (head || tail) { 3520 uint64_t off; 3521 unsigned int nr; 3522 3523 assert(head + bytes <= s->cluster_size); 3524 3525 /* check whether remainder of cluster already reads as zero */ 3526 if (!(is_zero(bs, offset - head, head) && 3527 is_zero(bs, offset + bytes, 3528 tail ? s->cluster_size - tail : 0))) { 3529 return -ENOTSUP; 3530 } 3531 3532 qemu_co_mutex_lock(&s->lock); 3533 /* We can have new write after previous check */ 3534 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3535 bytes = s->cluster_size; 3536 nr = s->cluster_size; 3537 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3538 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3539 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3540 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3541 qemu_co_mutex_unlock(&s->lock); 3542 return -ENOTSUP; 3543 } 3544 } else { 3545 qemu_co_mutex_lock(&s->lock); 3546 } 3547 3548 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3549 3550 /* Whatever is left can use real zero clusters */ 3551 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3552 qemu_co_mutex_unlock(&s->lock); 3553 3554 return ret; 3555 } 3556 3557 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3558 int64_t offset, int bytes) 3559 { 3560 int ret; 3561 BDRVQcow2State *s = bs->opaque; 3562 3563 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3564 assert(bytes < s->cluster_size); 3565 /* Ignore partial clusters, except for the special case of the 3566 * complete partial cluster at the end of an unaligned file */ 3567 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3568 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3569 return -ENOTSUP; 3570 } 3571 } 3572 3573 qemu_co_mutex_lock(&s->lock); 3574 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3575 false); 3576 qemu_co_mutex_unlock(&s->lock); 3577 return ret; 3578 } 3579 3580 static int coroutine_fn 3581 qcow2_co_copy_range_from(BlockDriverState *bs, 3582 BdrvChild *src, uint64_t src_offset, 3583 BdrvChild *dst, uint64_t dst_offset, 3584 uint64_t bytes, BdrvRequestFlags read_flags, 3585 BdrvRequestFlags write_flags) 3586 { 3587 BDRVQcow2State *s = bs->opaque; 3588 int ret; 3589 unsigned int cur_bytes; /* number of bytes in current iteration */ 3590 BdrvChild *child = NULL; 3591 BdrvRequestFlags cur_write_flags; 3592 3593 assert(!bs->encrypted); 3594 qemu_co_mutex_lock(&s->lock); 3595 3596 while (bytes != 0) { 3597 uint64_t copy_offset = 0; 3598 /* prepare next request */ 3599 cur_bytes = MIN(bytes, INT_MAX); 3600 cur_write_flags = write_flags; 3601 3602 ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, ©_offset); 3603 if (ret < 0) { 3604 goto out; 3605 } 3606 3607 switch (ret) { 3608 case QCOW2_CLUSTER_UNALLOCATED: 3609 if (bs->backing && bs->backing->bs) { 3610 int64_t backing_length = bdrv_getlength(bs->backing->bs); 3611 if (src_offset >= backing_length) { 3612 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3613 } else { 3614 child = bs->backing; 3615 cur_bytes = MIN(cur_bytes, backing_length - src_offset); 3616 copy_offset = src_offset; 3617 } 3618 } else { 3619 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3620 } 3621 break; 3622 3623 case QCOW2_CLUSTER_ZERO_PLAIN: 3624 case QCOW2_CLUSTER_ZERO_ALLOC: 3625 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3626 break; 3627 3628 case QCOW2_CLUSTER_COMPRESSED: 3629 ret = -ENOTSUP; 3630 goto out; 3631 3632 case QCOW2_CLUSTER_NORMAL: 3633 child = s->data_file; 3634 copy_offset += offset_into_cluster(s, src_offset); 3635 if ((copy_offset & 511) != 0) { 3636 ret = -EIO; 3637 goto out; 3638 } 3639 break; 3640 3641 default: 3642 abort(); 3643 } 3644 qemu_co_mutex_unlock(&s->lock); 3645 ret = bdrv_co_copy_range_from(child, 3646 copy_offset, 3647 dst, dst_offset, 3648 cur_bytes, read_flags, cur_write_flags); 3649 qemu_co_mutex_lock(&s->lock); 3650 if (ret < 0) { 3651 goto out; 3652 } 3653 3654 bytes -= cur_bytes; 3655 src_offset += cur_bytes; 3656 dst_offset += cur_bytes; 3657 } 3658 ret = 0; 3659 3660 out: 3661 qemu_co_mutex_unlock(&s->lock); 3662 return ret; 3663 } 3664 3665 static int coroutine_fn 3666 qcow2_co_copy_range_to(BlockDriverState *bs, 3667 BdrvChild *src, uint64_t src_offset, 3668 BdrvChild *dst, uint64_t dst_offset, 3669 uint64_t bytes, BdrvRequestFlags read_flags, 3670 BdrvRequestFlags write_flags) 3671 { 3672 BDRVQcow2State *s = bs->opaque; 3673 int offset_in_cluster; 3674 int ret; 3675 unsigned int cur_bytes; /* number of sectors in current iteration */ 3676 uint64_t cluster_offset; 3677 QCowL2Meta *l2meta = NULL; 3678 3679 assert(!bs->encrypted); 3680 3681 qemu_co_mutex_lock(&s->lock); 3682 3683 while (bytes != 0) { 3684 3685 l2meta = NULL; 3686 3687 offset_in_cluster = offset_into_cluster(s, dst_offset); 3688 cur_bytes = MIN(bytes, INT_MAX); 3689 3690 /* TODO: 3691 * If src->bs == dst->bs, we could simply copy by incrementing 3692 * the refcnt, without copying user data. 3693 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ 3694 ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes, 3695 &cluster_offset, &l2meta); 3696 if (ret < 0) { 3697 goto fail; 3698 } 3699 3700 assert((cluster_offset & 511) == 0); 3701 3702 ret = qcow2_pre_write_overlap_check(bs, 0, 3703 cluster_offset + offset_in_cluster, cur_bytes, true); 3704 if (ret < 0) { 3705 goto fail; 3706 } 3707 3708 qemu_co_mutex_unlock(&s->lock); 3709 ret = bdrv_co_copy_range_to(src, src_offset, 3710 s->data_file, 3711 cluster_offset + offset_in_cluster, 3712 cur_bytes, read_flags, write_flags); 3713 qemu_co_mutex_lock(&s->lock); 3714 if (ret < 0) { 3715 goto fail; 3716 } 3717 3718 ret = qcow2_handle_l2meta(bs, &l2meta, true); 3719 if (ret) { 3720 goto fail; 3721 } 3722 3723 bytes -= cur_bytes; 3724 src_offset += cur_bytes; 3725 dst_offset += cur_bytes; 3726 } 3727 ret = 0; 3728 3729 fail: 3730 qcow2_handle_l2meta(bs, &l2meta, false); 3731 3732 qemu_co_mutex_unlock(&s->lock); 3733 3734 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 3735 3736 return ret; 3737 } 3738 3739 static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, 3740 PreallocMode prealloc, Error **errp) 3741 { 3742 BDRVQcow2State *s = bs->opaque; 3743 uint64_t old_length; 3744 int64_t new_l1_size; 3745 int ret; 3746 QDict *options; 3747 3748 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3749 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3750 { 3751 error_setg(errp, "Unsupported preallocation mode '%s'", 3752 PreallocMode_str(prealloc)); 3753 return -ENOTSUP; 3754 } 3755 3756 if (offset & 511) { 3757 error_setg(errp, "The new size must be a multiple of 512"); 3758 return -EINVAL; 3759 } 3760 3761 qemu_co_mutex_lock(&s->lock); 3762 3763 /* cannot proceed if image has snapshots */ 3764 if (s->nb_snapshots) { 3765 error_setg(errp, "Can't resize an image which has snapshots"); 3766 ret = -ENOTSUP; 3767 goto fail; 3768 } 3769 3770 /* cannot proceed if image has bitmaps */ 3771 if (qcow2_truncate_bitmaps_check(bs, errp)) { 3772 ret = -ENOTSUP; 3773 goto fail; 3774 } 3775 3776 old_length = bs->total_sectors * BDRV_SECTOR_SIZE; 3777 new_l1_size = size_to_l1(s, offset); 3778 3779 if (offset < old_length) { 3780 int64_t last_cluster, old_file_size; 3781 if (prealloc != PREALLOC_MODE_OFF) { 3782 error_setg(errp, 3783 "Preallocation can't be used for shrinking an image"); 3784 ret = -EINVAL; 3785 goto fail; 3786 } 3787 3788 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3789 old_length - ROUND_UP(offset, 3790 s->cluster_size), 3791 QCOW2_DISCARD_ALWAYS, true); 3792 if (ret < 0) { 3793 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3794 goto fail; 3795 } 3796 3797 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3798 if (ret < 0) { 3799 error_setg_errno(errp, -ret, 3800 "Failed to reduce the number of L2 tables"); 3801 goto fail; 3802 } 3803 3804 ret = qcow2_shrink_reftable(bs); 3805 if (ret < 0) { 3806 error_setg_errno(errp, -ret, 3807 "Failed to discard unused refblocks"); 3808 goto fail; 3809 } 3810 3811 old_file_size = bdrv_getlength(bs->file->bs); 3812 if (old_file_size < 0) { 3813 error_setg_errno(errp, -old_file_size, 3814 "Failed to inquire current file length"); 3815 ret = old_file_size; 3816 goto fail; 3817 } 3818 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3819 if (last_cluster < 0) { 3820 error_setg_errno(errp, -last_cluster, 3821 "Failed to find the last cluster"); 3822 ret = last_cluster; 3823 goto fail; 3824 } 3825 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3826 Error *local_err = NULL; 3827 3828 bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3829 PREALLOC_MODE_OFF, &local_err); 3830 if (local_err) { 3831 warn_reportf_err(local_err, 3832 "Failed to truncate the tail of the image: "); 3833 } 3834 } 3835 } else { 3836 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3837 if (ret < 0) { 3838 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3839 goto fail; 3840 } 3841 } 3842 3843 switch (prealloc) { 3844 case PREALLOC_MODE_OFF: 3845 if (has_data_file(bs)) { 3846 ret = bdrv_co_truncate(s->data_file, offset, prealloc, errp); 3847 if (ret < 0) { 3848 goto fail; 3849 } 3850 } 3851 break; 3852 3853 case PREALLOC_MODE_METADATA: 3854 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 3855 if (ret < 0) { 3856 goto fail; 3857 } 3858 break; 3859 3860 case PREALLOC_MODE_FALLOC: 3861 case PREALLOC_MODE_FULL: 3862 { 3863 int64_t allocation_start, host_offset, guest_offset; 3864 int64_t clusters_allocated; 3865 int64_t old_file_size, new_file_size; 3866 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3867 3868 /* With a data file, preallocation means just allocating the metadata 3869 * and forwarding the truncate request to the data file */ 3870 if (has_data_file(bs)) { 3871 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 3872 if (ret < 0) { 3873 goto fail; 3874 } 3875 break; 3876 } 3877 3878 old_file_size = bdrv_getlength(bs->file->bs); 3879 if (old_file_size < 0) { 3880 error_setg_errno(errp, -old_file_size, 3881 "Failed to inquire current file length"); 3882 ret = old_file_size; 3883 goto fail; 3884 } 3885 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3886 3887 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3888 s->cluster_size); 3889 3890 /* This is an overestimation; we will not actually allocate space for 3891 * these in the file but just make sure the new refcount structures are 3892 * able to cover them so we will not have to allocate new refblocks 3893 * while entering the data blocks in the potentially new L2 tables. 3894 * (We do not actually care where the L2 tables are placed. Maybe they 3895 * are already allocated or they can be placed somewhere before 3896 * @old_file_size. It does not matter because they will be fully 3897 * allocated automatically, so they do not need to be covered by the 3898 * preallocation. All that matters is that we will not have to allocate 3899 * new refcount structures for them.) */ 3900 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3901 s->cluster_size / sizeof(uint64_t)); 3902 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3903 * table for a potential head/tail */ 3904 nb_new_l2_tables++; 3905 3906 allocation_start = qcow2_refcount_area(bs, old_file_size, 3907 nb_new_data_clusters + 3908 nb_new_l2_tables, 3909 true, 0, 0); 3910 if (allocation_start < 0) { 3911 error_setg_errno(errp, -allocation_start, 3912 "Failed to resize refcount structures"); 3913 ret = allocation_start; 3914 goto fail; 3915 } 3916 3917 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3918 nb_new_data_clusters); 3919 if (clusters_allocated < 0) { 3920 error_setg_errno(errp, -clusters_allocated, 3921 "Failed to allocate data clusters"); 3922 ret = clusters_allocated; 3923 goto fail; 3924 } 3925 3926 assert(clusters_allocated == nb_new_data_clusters); 3927 3928 /* Allocate the data area */ 3929 new_file_size = allocation_start + 3930 nb_new_data_clusters * s->cluster_size; 3931 ret = bdrv_co_truncate(bs->file, new_file_size, prealloc, errp); 3932 if (ret < 0) { 3933 error_prepend(errp, "Failed to resize underlying file: "); 3934 qcow2_free_clusters(bs, allocation_start, 3935 nb_new_data_clusters * s->cluster_size, 3936 QCOW2_DISCARD_OTHER); 3937 goto fail; 3938 } 3939 3940 /* Create the necessary L2 entries */ 3941 host_offset = allocation_start; 3942 guest_offset = old_length; 3943 while (nb_new_data_clusters) { 3944 int64_t nb_clusters = MIN( 3945 nb_new_data_clusters, 3946 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3947 QCowL2Meta allocation = { 3948 .offset = guest_offset, 3949 .alloc_offset = host_offset, 3950 .nb_clusters = nb_clusters, 3951 }; 3952 qemu_co_queue_init(&allocation.dependent_requests); 3953 3954 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3955 if (ret < 0) { 3956 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3957 qcow2_free_clusters(bs, host_offset, 3958 nb_new_data_clusters * s->cluster_size, 3959 QCOW2_DISCARD_OTHER); 3960 goto fail; 3961 } 3962 3963 guest_offset += nb_clusters * s->cluster_size; 3964 host_offset += nb_clusters * s->cluster_size; 3965 nb_new_data_clusters -= nb_clusters; 3966 } 3967 break; 3968 } 3969 3970 default: 3971 g_assert_not_reached(); 3972 } 3973 3974 if (prealloc != PREALLOC_MODE_OFF) { 3975 /* Flush metadata before actually changing the image size */ 3976 ret = qcow2_write_caches(bs); 3977 if (ret < 0) { 3978 error_setg_errno(errp, -ret, 3979 "Failed to flush the preallocated area to disk"); 3980 goto fail; 3981 } 3982 } 3983 3984 bs->total_sectors = offset / BDRV_SECTOR_SIZE; 3985 3986 /* write updated header.size */ 3987 offset = cpu_to_be64(offset); 3988 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3989 &offset, sizeof(uint64_t)); 3990 if (ret < 0) { 3991 error_setg_errno(errp, -ret, "Failed to update the image size"); 3992 goto fail; 3993 } 3994 3995 s->l1_vm_state_index = new_l1_size; 3996 3997 /* Update cache sizes */ 3998 options = qdict_clone_shallow(bs->options); 3999 ret = qcow2_update_options(bs, options, s->flags, errp); 4000 qobject_unref(options); 4001 if (ret < 0) { 4002 goto fail; 4003 } 4004 ret = 0; 4005 fail: 4006 qemu_co_mutex_unlock(&s->lock); 4007 return ret; 4008 } 4009 4010 /* XXX: put compressed sectors first, then all the cluster aligned 4011 tables to avoid losing bytes in alignment */ 4012 static coroutine_fn int 4013 qcow2_co_pwritev_compressed_part(BlockDriverState *bs, 4014 uint64_t offset, uint64_t bytes, 4015 QEMUIOVector *qiov, size_t qiov_offset) 4016 { 4017 BDRVQcow2State *s = bs->opaque; 4018 int ret; 4019 ssize_t out_len; 4020 uint8_t *buf, *out_buf; 4021 uint64_t cluster_offset; 4022 4023 if (has_data_file(bs)) { 4024 return -ENOTSUP; 4025 } 4026 4027 if (bytes == 0) { 4028 /* align end of file to a sector boundary to ease reading with 4029 sector based I/Os */ 4030 int64_t len = bdrv_getlength(bs->file->bs); 4031 if (len < 0) { 4032 return len; 4033 } 4034 return bdrv_co_truncate(bs->file, len, PREALLOC_MODE_OFF, NULL); 4035 } 4036 4037 if (offset_into_cluster(s, offset)) { 4038 return -EINVAL; 4039 } 4040 4041 buf = qemu_blockalign(bs, s->cluster_size); 4042 if (bytes != s->cluster_size) { 4043 if (bytes > s->cluster_size || 4044 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 4045 { 4046 qemu_vfree(buf); 4047 return -EINVAL; 4048 } 4049 /* Zero-pad last write if image size is not cluster aligned */ 4050 memset(buf + bytes, 0, s->cluster_size - bytes); 4051 } 4052 qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes); 4053 4054 out_buf = g_malloc(s->cluster_size); 4055 4056 out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1, 4057 buf, s->cluster_size); 4058 if (out_len == -ENOMEM) { 4059 /* could not compress: write normal cluster */ 4060 ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0); 4061 if (ret < 0) { 4062 goto fail; 4063 } 4064 goto success; 4065 } else if (out_len < 0) { 4066 ret = -EINVAL; 4067 goto fail; 4068 } 4069 4070 qemu_co_mutex_lock(&s->lock); 4071 ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len, 4072 &cluster_offset); 4073 if (ret < 0) { 4074 qemu_co_mutex_unlock(&s->lock); 4075 goto fail; 4076 } 4077 4078 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true); 4079 qemu_co_mutex_unlock(&s->lock); 4080 if (ret < 0) { 4081 goto fail; 4082 } 4083 4084 BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED); 4085 ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0); 4086 if (ret < 0) { 4087 goto fail; 4088 } 4089 success: 4090 ret = 0; 4091 fail: 4092 qemu_vfree(buf); 4093 g_free(out_buf); 4094 return ret; 4095 } 4096 4097 static int coroutine_fn 4098 qcow2_co_preadv_compressed(BlockDriverState *bs, 4099 uint64_t file_cluster_offset, 4100 uint64_t offset, 4101 uint64_t bytes, 4102 QEMUIOVector *qiov, 4103 size_t qiov_offset) 4104 { 4105 BDRVQcow2State *s = bs->opaque; 4106 int ret = 0, csize, nb_csectors; 4107 uint64_t coffset; 4108 uint8_t *buf, *out_buf; 4109 int offset_in_cluster = offset_into_cluster(s, offset); 4110 4111 coffset = file_cluster_offset & s->cluster_offset_mask; 4112 nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1; 4113 csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - 4114 (coffset & ~QCOW2_COMPRESSED_SECTOR_MASK); 4115 4116 buf = g_try_malloc(csize); 4117 if (!buf) { 4118 return -ENOMEM; 4119 } 4120 4121 out_buf = qemu_blockalign(bs, s->cluster_size); 4122 4123 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 4124 ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0); 4125 if (ret < 0) { 4126 goto fail; 4127 } 4128 4129 if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) { 4130 ret = -EIO; 4131 goto fail; 4132 } 4133 4134 qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes); 4135 4136 fail: 4137 qemu_vfree(out_buf); 4138 g_free(buf); 4139 4140 return ret; 4141 } 4142 4143 static int make_completely_empty(BlockDriverState *bs) 4144 { 4145 BDRVQcow2State *s = bs->opaque; 4146 Error *local_err = NULL; 4147 int ret, l1_clusters; 4148 int64_t offset; 4149 uint64_t *new_reftable = NULL; 4150 uint64_t rt_entry, l1_size2; 4151 struct { 4152 uint64_t l1_offset; 4153 uint64_t reftable_offset; 4154 uint32_t reftable_clusters; 4155 } QEMU_PACKED l1_ofs_rt_ofs_cls; 4156 4157 ret = qcow2_cache_empty(bs, s->l2_table_cache); 4158 if (ret < 0) { 4159 goto fail; 4160 } 4161 4162 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 4163 if (ret < 0) { 4164 goto fail; 4165 } 4166 4167 /* Refcounts will be broken utterly */ 4168 ret = qcow2_mark_dirty(bs); 4169 if (ret < 0) { 4170 goto fail; 4171 } 4172 4173 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4174 4175 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4176 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 4177 4178 /* After this call, neither the in-memory nor the on-disk refcount 4179 * information accurately describe the actual references */ 4180 4181 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 4182 l1_clusters * s->cluster_size, 0); 4183 if (ret < 0) { 4184 goto fail_broken_refcounts; 4185 } 4186 memset(s->l1_table, 0, l1_size2); 4187 4188 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 4189 4190 /* Overwrite enough clusters at the beginning of the sectors to place 4191 * the refcount table, a refcount block and the L1 table in; this may 4192 * overwrite parts of the existing refcount and L1 table, which is not 4193 * an issue because the dirty flag is set, complete data loss is in fact 4194 * desired and partial data loss is consequently fine as well */ 4195 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 4196 (2 + l1_clusters) * s->cluster_size, 0); 4197 /* This call (even if it failed overall) may have overwritten on-disk 4198 * refcount structures; in that case, the in-memory refcount information 4199 * will probably differ from the on-disk information which makes the BDS 4200 * unusable */ 4201 if (ret < 0) { 4202 goto fail_broken_refcounts; 4203 } 4204 4205 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4206 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 4207 4208 /* "Create" an empty reftable (one cluster) directly after the image 4209 * header and an empty L1 table three clusters after the image header; 4210 * the cluster between those two will be used as the first refblock */ 4211 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 4212 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 4213 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 4214 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 4215 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 4216 if (ret < 0) { 4217 goto fail_broken_refcounts; 4218 } 4219 4220 s->l1_table_offset = 3 * s->cluster_size; 4221 4222 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 4223 if (!new_reftable) { 4224 ret = -ENOMEM; 4225 goto fail_broken_refcounts; 4226 } 4227 4228 s->refcount_table_offset = s->cluster_size; 4229 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 4230 s->max_refcount_table_index = 0; 4231 4232 g_free(s->refcount_table); 4233 s->refcount_table = new_reftable; 4234 new_reftable = NULL; 4235 4236 /* Now the in-memory refcount information again corresponds to the on-disk 4237 * information (reftable is empty and no refblocks (the refblock cache is 4238 * empty)); however, this means some clusters (e.g. the image header) are 4239 * referenced, but not refcounted, but the normal qcow2 code assumes that 4240 * the in-memory information is always correct */ 4241 4242 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 4243 4244 /* Enter the first refblock into the reftable */ 4245 rt_entry = cpu_to_be64(2 * s->cluster_size); 4246 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 4247 &rt_entry, sizeof(rt_entry)); 4248 if (ret < 0) { 4249 goto fail_broken_refcounts; 4250 } 4251 s->refcount_table[0] = 2 * s->cluster_size; 4252 4253 s->free_cluster_index = 0; 4254 assert(3 + l1_clusters <= s->refcount_block_size); 4255 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 4256 if (offset < 0) { 4257 ret = offset; 4258 goto fail_broken_refcounts; 4259 } else if (offset > 0) { 4260 error_report("First cluster in emptied image is in use"); 4261 abort(); 4262 } 4263 4264 /* Now finally the in-memory information corresponds to the on-disk 4265 * structures and is correct */ 4266 ret = qcow2_mark_clean(bs); 4267 if (ret < 0) { 4268 goto fail; 4269 } 4270 4271 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 4272 PREALLOC_MODE_OFF, &local_err); 4273 if (ret < 0) { 4274 error_report_err(local_err); 4275 goto fail; 4276 } 4277 4278 return 0; 4279 4280 fail_broken_refcounts: 4281 /* The BDS is unusable at this point. If we wanted to make it usable, we 4282 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 4283 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 4284 * again. However, because the functions which could have caused this error 4285 * path to be taken are used by those functions as well, it's very likely 4286 * that that sequence will fail as well. Therefore, just eject the BDS. */ 4287 bs->drv = NULL; 4288 4289 fail: 4290 g_free(new_reftable); 4291 return ret; 4292 } 4293 4294 static int qcow2_make_empty(BlockDriverState *bs) 4295 { 4296 BDRVQcow2State *s = bs->opaque; 4297 uint64_t offset, end_offset; 4298 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 4299 int l1_clusters, ret = 0; 4300 4301 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4302 4303 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 4304 3 + l1_clusters <= s->refcount_block_size && 4305 s->crypt_method_header != QCOW_CRYPT_LUKS && 4306 !has_data_file(bs)) { 4307 /* The following function only works for qcow2 v3 images (it 4308 * requires the dirty flag) and only as long as there are no 4309 * features that reserve extra clusters (such as snapshots, 4310 * LUKS header, or persistent bitmaps), because it completely 4311 * empties the image. Furthermore, the L1 table and three 4312 * additional clusters (image header, refcount table, one 4313 * refcount block) have to fit inside one refcount block. It 4314 * only resets the image file, i.e. does not work with an 4315 * external data file. */ 4316 return make_completely_empty(bs); 4317 } 4318 4319 /* This fallback code simply discards every active cluster; this is slow, 4320 * but works in all cases */ 4321 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 4322 for (offset = 0; offset < end_offset; offset += step) { 4323 /* As this function is generally used after committing an external 4324 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 4325 * default action for this kind of discard is to pass the discard, 4326 * which will ideally result in an actually smaller image file, as 4327 * is probably desired. */ 4328 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 4329 QCOW2_DISCARD_SNAPSHOT, true); 4330 if (ret < 0) { 4331 break; 4332 } 4333 } 4334 4335 return ret; 4336 } 4337 4338 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 4339 { 4340 BDRVQcow2State *s = bs->opaque; 4341 int ret; 4342 4343 qemu_co_mutex_lock(&s->lock); 4344 ret = qcow2_write_caches(bs); 4345 qemu_co_mutex_unlock(&s->lock); 4346 4347 return ret; 4348 } 4349 4350 static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block, 4351 size_t headerlen, void *opaque, Error **errp) 4352 { 4353 size_t *headerlenp = opaque; 4354 4355 /* Stash away the payload size */ 4356 *headerlenp = headerlen; 4357 return 0; 4358 } 4359 4360 static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block, 4361 size_t offset, const uint8_t *buf, size_t buflen, 4362 void *opaque, Error **errp) 4363 { 4364 /* Discard the bytes, we're not actually writing to an image */ 4365 return buflen; 4366 } 4367 4368 /* Determine the number of bytes for the LUKS payload */ 4369 static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len, 4370 Error **errp) 4371 { 4372 QDict *opts_qdict; 4373 QDict *cryptoopts_qdict; 4374 QCryptoBlockCreateOptions *cryptoopts; 4375 QCryptoBlock *crypto; 4376 4377 /* Extract "encrypt." options into a qdict */ 4378 opts_qdict = qemu_opts_to_qdict(opts, NULL); 4379 qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt."); 4380 qobject_unref(opts_qdict); 4381 4382 /* Build QCryptoBlockCreateOptions object from qdict */ 4383 qdict_put_str(cryptoopts_qdict, "format", "luks"); 4384 cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp); 4385 qobject_unref(cryptoopts_qdict); 4386 if (!cryptoopts) { 4387 return false; 4388 } 4389 4390 /* Fake LUKS creation in order to determine the payload size */ 4391 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 4392 qcow2_measure_crypto_hdr_init_func, 4393 qcow2_measure_crypto_hdr_write_func, 4394 len, errp); 4395 qapi_free_QCryptoBlockCreateOptions(cryptoopts); 4396 if (!crypto) { 4397 return false; 4398 } 4399 4400 qcrypto_block_free(crypto); 4401 return true; 4402 } 4403 4404 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 4405 Error **errp) 4406 { 4407 Error *local_err = NULL; 4408 BlockMeasureInfo *info; 4409 uint64_t required = 0; /* bytes that contribute to required size */ 4410 uint64_t virtual_size; /* disk size as seen by guest */ 4411 uint64_t refcount_bits; 4412 uint64_t l2_tables; 4413 uint64_t luks_payload_size = 0; 4414 size_t cluster_size; 4415 int version; 4416 char *optstr; 4417 PreallocMode prealloc; 4418 bool has_backing_file; 4419 bool has_luks; 4420 4421 /* Parse image creation options */ 4422 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 4423 if (local_err) { 4424 goto err; 4425 } 4426 4427 version = qcow2_opt_get_version_del(opts, &local_err); 4428 if (local_err) { 4429 goto err; 4430 } 4431 4432 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 4433 if (local_err) { 4434 goto err; 4435 } 4436 4437 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 4438 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 4439 PREALLOC_MODE_OFF, &local_err); 4440 g_free(optstr); 4441 if (local_err) { 4442 goto err; 4443 } 4444 4445 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 4446 has_backing_file = !!optstr; 4447 g_free(optstr); 4448 4449 optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 4450 has_luks = optstr && strcmp(optstr, "luks") == 0; 4451 g_free(optstr); 4452 4453 if (has_luks) { 4454 size_t headerlen; 4455 4456 if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) { 4457 goto err; 4458 } 4459 4460 luks_payload_size = ROUND_UP(headerlen, cluster_size); 4461 } 4462 4463 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 4464 virtual_size = ROUND_UP(virtual_size, cluster_size); 4465 4466 /* Check that virtual disk size is valid */ 4467 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 4468 cluster_size / sizeof(uint64_t)); 4469 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 4470 error_setg(&local_err, "The image size is too large " 4471 "(try using a larger cluster size)"); 4472 goto err; 4473 } 4474 4475 /* Account for input image */ 4476 if (in_bs) { 4477 int64_t ssize = bdrv_getlength(in_bs); 4478 if (ssize < 0) { 4479 error_setg_errno(&local_err, -ssize, 4480 "Unable to get image virtual_size"); 4481 goto err; 4482 } 4483 4484 virtual_size = ROUND_UP(ssize, cluster_size); 4485 4486 if (has_backing_file) { 4487 /* We don't how much of the backing chain is shared by the input 4488 * image and the new image file. In the worst case the new image's 4489 * backing file has nothing in common with the input image. Be 4490 * conservative and assume all clusters need to be written. 4491 */ 4492 required = virtual_size; 4493 } else { 4494 int64_t offset; 4495 int64_t pnum = 0; 4496 4497 for (offset = 0; offset < ssize; offset += pnum) { 4498 int ret; 4499 4500 ret = bdrv_block_status_above(in_bs, NULL, offset, 4501 ssize - offset, &pnum, NULL, 4502 NULL); 4503 if (ret < 0) { 4504 error_setg_errno(&local_err, -ret, 4505 "Unable to get block status"); 4506 goto err; 4507 } 4508 4509 if (ret & BDRV_BLOCK_ZERO) { 4510 /* Skip zero regions (safe with no backing file) */ 4511 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 4512 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 4513 /* Extend pnum to end of cluster for next iteration */ 4514 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 4515 4516 /* Count clusters we've seen */ 4517 required += offset % cluster_size + pnum; 4518 } 4519 } 4520 } 4521 } 4522 4523 /* Take into account preallocation. Nothing special is needed for 4524 * PREALLOC_MODE_METADATA since metadata is always counted. 4525 */ 4526 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 4527 required = virtual_size; 4528 } 4529 4530 info = g_new(BlockMeasureInfo, 1); 4531 info->fully_allocated = 4532 qcow2_calc_prealloc_size(virtual_size, cluster_size, 4533 ctz32(refcount_bits)) + luks_payload_size; 4534 4535 /* Remove data clusters that are not required. This overestimates the 4536 * required size because metadata needed for the fully allocated file is 4537 * still counted. 4538 */ 4539 info->required = info->fully_allocated - virtual_size + required; 4540 return info; 4541 4542 err: 4543 error_propagate(errp, local_err); 4544 return NULL; 4545 } 4546 4547 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4548 { 4549 BDRVQcow2State *s = bs->opaque; 4550 bdi->unallocated_blocks_are_zero = true; 4551 bdi->cluster_size = s->cluster_size; 4552 bdi->vm_state_offset = qcow2_vm_state_offset(s); 4553 return 0; 4554 } 4555 4556 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, 4557 Error **errp) 4558 { 4559 BDRVQcow2State *s = bs->opaque; 4560 ImageInfoSpecific *spec_info; 4561 QCryptoBlockInfo *encrypt_info = NULL; 4562 Error *local_err = NULL; 4563 4564 if (s->crypto != NULL) { 4565 encrypt_info = qcrypto_block_get_info(s->crypto, &local_err); 4566 if (local_err) { 4567 error_propagate(errp, local_err); 4568 return NULL; 4569 } 4570 } 4571 4572 spec_info = g_new(ImageInfoSpecific, 1); 4573 *spec_info = (ImageInfoSpecific){ 4574 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 4575 .u.qcow2.data = g_new0(ImageInfoSpecificQCow2, 1), 4576 }; 4577 if (s->qcow_version == 2) { 4578 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4579 .compat = g_strdup("0.10"), 4580 .refcount_bits = s->refcount_bits, 4581 }; 4582 } else if (s->qcow_version == 3) { 4583 Qcow2BitmapInfoList *bitmaps; 4584 bitmaps = qcow2_get_bitmap_info_list(bs, &local_err); 4585 if (local_err) { 4586 error_propagate(errp, local_err); 4587 qapi_free_ImageInfoSpecific(spec_info); 4588 return NULL; 4589 } 4590 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4591 .compat = g_strdup("1.1"), 4592 .lazy_refcounts = s->compatible_features & 4593 QCOW2_COMPAT_LAZY_REFCOUNTS, 4594 .has_lazy_refcounts = true, 4595 .corrupt = s->incompatible_features & 4596 QCOW2_INCOMPAT_CORRUPT, 4597 .has_corrupt = true, 4598 .refcount_bits = s->refcount_bits, 4599 .has_bitmaps = !!bitmaps, 4600 .bitmaps = bitmaps, 4601 .has_data_file = !!s->image_data_file, 4602 .data_file = g_strdup(s->image_data_file), 4603 .has_data_file_raw = has_data_file(bs), 4604 .data_file_raw = data_file_is_raw(bs), 4605 }; 4606 } else { 4607 /* if this assertion fails, this probably means a new version was 4608 * added without having it covered here */ 4609 assert(false); 4610 } 4611 4612 if (encrypt_info) { 4613 ImageInfoSpecificQCow2Encryption *qencrypt = 4614 g_new(ImageInfoSpecificQCow2Encryption, 1); 4615 switch (encrypt_info->format) { 4616 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 4617 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 4618 break; 4619 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 4620 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 4621 qencrypt->u.luks = encrypt_info->u.luks; 4622 break; 4623 default: 4624 abort(); 4625 } 4626 /* Since we did shallow copy above, erase any pointers 4627 * in the original info */ 4628 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 4629 qapi_free_QCryptoBlockInfo(encrypt_info); 4630 4631 spec_info->u.qcow2.data->has_encrypt = true; 4632 spec_info->u.qcow2.data->encrypt = qencrypt; 4633 } 4634 4635 return spec_info; 4636 } 4637 4638 static int qcow2_has_zero_init(BlockDriverState *bs) 4639 { 4640 BDRVQcow2State *s = bs->opaque; 4641 bool preallocated; 4642 4643 if (qemu_in_coroutine()) { 4644 qemu_co_mutex_lock(&s->lock); 4645 } 4646 /* 4647 * Check preallocation status: Preallocated images have all L2 4648 * tables allocated, nonpreallocated images have none. It is 4649 * therefore enough to check the first one. 4650 */ 4651 preallocated = s->l1_size > 0 && s->l1_table[0] != 0; 4652 if (qemu_in_coroutine()) { 4653 qemu_co_mutex_unlock(&s->lock); 4654 } 4655 4656 if (!preallocated) { 4657 return 1; 4658 } else if (bs->encrypted) { 4659 return 0; 4660 } else { 4661 return bdrv_has_zero_init(s->data_file->bs); 4662 } 4663 } 4664 4665 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4666 int64_t pos) 4667 { 4668 BDRVQcow2State *s = bs->opaque; 4669 4670 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 4671 return bs->drv->bdrv_co_pwritev_part(bs, qcow2_vm_state_offset(s) + pos, 4672 qiov->size, qiov, 0, 0); 4673 } 4674 4675 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4676 int64_t pos) 4677 { 4678 BDRVQcow2State *s = bs->opaque; 4679 4680 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 4681 return bs->drv->bdrv_co_preadv_part(bs, qcow2_vm_state_offset(s) + pos, 4682 qiov->size, qiov, 0, 0); 4683 } 4684 4685 /* 4686 * Downgrades an image's version. To achieve this, any incompatible features 4687 * have to be removed. 4688 */ 4689 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 4690 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 4691 Error **errp) 4692 { 4693 BDRVQcow2State *s = bs->opaque; 4694 int current_version = s->qcow_version; 4695 int ret; 4696 4697 /* This is qcow2_downgrade(), not qcow2_upgrade() */ 4698 assert(target_version < current_version); 4699 4700 /* There are no other versions (now) that you can downgrade to */ 4701 assert(target_version == 2); 4702 4703 if (s->refcount_order != 4) { 4704 error_setg(errp, "compat=0.10 requires refcount_bits=16"); 4705 return -ENOTSUP; 4706 } 4707 4708 if (has_data_file(bs)) { 4709 error_setg(errp, "Cannot downgrade an image with a data file"); 4710 return -ENOTSUP; 4711 } 4712 4713 /* clear incompatible features */ 4714 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 4715 ret = qcow2_mark_clean(bs); 4716 if (ret < 0) { 4717 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4718 return ret; 4719 } 4720 } 4721 4722 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 4723 * the first place; if that happens nonetheless, returning -ENOTSUP is the 4724 * best thing to do anyway */ 4725 4726 if (s->incompatible_features) { 4727 error_setg(errp, "Cannot downgrade an image with incompatible features " 4728 "%#" PRIx64 " set", s->incompatible_features); 4729 return -ENOTSUP; 4730 } 4731 4732 /* since we can ignore compatible features, we can set them to 0 as well */ 4733 s->compatible_features = 0; 4734 /* if lazy refcounts have been used, they have already been fixed through 4735 * clearing the dirty flag */ 4736 4737 /* clearing autoclear features is trivial */ 4738 s->autoclear_features = 0; 4739 4740 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 4741 if (ret < 0) { 4742 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); 4743 return ret; 4744 } 4745 4746 s->qcow_version = target_version; 4747 ret = qcow2_update_header(bs); 4748 if (ret < 0) { 4749 s->qcow_version = current_version; 4750 error_setg_errno(errp, -ret, "Failed to update the image header"); 4751 return ret; 4752 } 4753 return 0; 4754 } 4755 4756 typedef enum Qcow2AmendOperation { 4757 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 4758 * statically initialized to so that the helper CB can discern the first 4759 * invocation from an operation change */ 4760 QCOW2_NO_OPERATION = 0, 4761 4762 QCOW2_CHANGING_REFCOUNT_ORDER, 4763 QCOW2_DOWNGRADING, 4764 } Qcow2AmendOperation; 4765 4766 typedef struct Qcow2AmendHelperCBInfo { 4767 /* The code coordinating the amend operations should only modify 4768 * these four fields; the rest will be managed by the CB */ 4769 BlockDriverAmendStatusCB *original_status_cb; 4770 void *original_cb_opaque; 4771 4772 Qcow2AmendOperation current_operation; 4773 4774 /* Total number of operations to perform (only set once) */ 4775 int total_operations; 4776 4777 /* The following fields are managed by the CB */ 4778 4779 /* Number of operations completed */ 4780 int operations_completed; 4781 4782 /* Cumulative offset of all completed operations */ 4783 int64_t offset_completed; 4784 4785 Qcow2AmendOperation last_operation; 4786 int64_t last_work_size; 4787 } Qcow2AmendHelperCBInfo; 4788 4789 static void qcow2_amend_helper_cb(BlockDriverState *bs, 4790 int64_t operation_offset, 4791 int64_t operation_work_size, void *opaque) 4792 { 4793 Qcow2AmendHelperCBInfo *info = opaque; 4794 int64_t current_work_size; 4795 int64_t projected_work_size; 4796 4797 if (info->current_operation != info->last_operation) { 4798 if (info->last_operation != QCOW2_NO_OPERATION) { 4799 info->offset_completed += info->last_work_size; 4800 info->operations_completed++; 4801 } 4802 4803 info->last_operation = info->current_operation; 4804 } 4805 4806 assert(info->total_operations > 0); 4807 assert(info->operations_completed < info->total_operations); 4808 4809 info->last_work_size = operation_work_size; 4810 4811 current_work_size = info->offset_completed + operation_work_size; 4812 4813 /* current_work_size is the total work size for (operations_completed + 1) 4814 * operations (which includes this one), so multiply it by the number of 4815 * operations not covered and divide it by the number of operations 4816 * covered to get a projection for the operations not covered */ 4817 projected_work_size = current_work_size * (info->total_operations - 4818 info->operations_completed - 1) 4819 / (info->operations_completed + 1); 4820 4821 info->original_status_cb(bs, info->offset_completed + operation_offset, 4822 current_work_size + projected_work_size, 4823 info->original_cb_opaque); 4824 } 4825 4826 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4827 BlockDriverAmendStatusCB *status_cb, 4828 void *cb_opaque, 4829 Error **errp) 4830 { 4831 BDRVQcow2State *s = bs->opaque; 4832 int old_version = s->qcow_version, new_version = old_version; 4833 uint64_t new_size = 0; 4834 const char *backing_file = NULL, *backing_format = NULL, *data_file = NULL; 4835 bool lazy_refcounts = s->use_lazy_refcounts; 4836 bool data_file_raw = data_file_is_raw(bs); 4837 const char *compat = NULL; 4838 uint64_t cluster_size = s->cluster_size; 4839 bool encrypt; 4840 int encformat; 4841 int refcount_bits = s->refcount_bits; 4842 int ret; 4843 QemuOptDesc *desc = opts->list->desc; 4844 Qcow2AmendHelperCBInfo helper_cb_info; 4845 4846 while (desc && desc->name) { 4847 if (!qemu_opt_find(opts, desc->name)) { 4848 /* only change explicitly defined options */ 4849 desc++; 4850 continue; 4851 } 4852 4853 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4854 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4855 if (!compat) { 4856 /* preserve default */ 4857 } else if (!strcmp(compat, "0.10") || !strcmp(compat, "v2")) { 4858 new_version = 2; 4859 } else if (!strcmp(compat, "1.1") || !strcmp(compat, "v3")) { 4860 new_version = 3; 4861 } else { 4862 error_setg(errp, "Unknown compatibility level %s", compat); 4863 return -EINVAL; 4864 } 4865 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4866 error_setg(errp, "Cannot change preallocation mode"); 4867 return -ENOTSUP; 4868 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4869 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4870 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4871 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4872 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4873 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4874 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4875 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4876 !!s->crypto); 4877 4878 if (encrypt != !!s->crypto) { 4879 error_setg(errp, 4880 "Changing the encryption flag is not supported"); 4881 return -ENOTSUP; 4882 } 4883 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4884 encformat = qcow2_crypt_method_from_format( 4885 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4886 4887 if (encformat != s->crypt_method_header) { 4888 error_setg(errp, 4889 "Changing the encryption format is not supported"); 4890 return -ENOTSUP; 4891 } 4892 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4893 error_setg(errp, 4894 "Changing the encryption parameters is not supported"); 4895 return -ENOTSUP; 4896 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4897 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4898 cluster_size); 4899 if (cluster_size != s->cluster_size) { 4900 error_setg(errp, "Changing the cluster size is not supported"); 4901 return -ENOTSUP; 4902 } 4903 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4904 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4905 lazy_refcounts); 4906 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4907 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4908 refcount_bits); 4909 4910 if (refcount_bits <= 0 || refcount_bits > 64 || 4911 !is_power_of_2(refcount_bits)) 4912 { 4913 error_setg(errp, "Refcount width must be a power of two and " 4914 "may not exceed 64 bits"); 4915 return -EINVAL; 4916 } 4917 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) { 4918 data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE); 4919 if (data_file && !has_data_file(bs)) { 4920 error_setg(errp, "data-file can only be set for images that " 4921 "use an external data file"); 4922 return -EINVAL; 4923 } 4924 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) { 4925 data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW, 4926 data_file_raw); 4927 if (data_file_raw && !data_file_is_raw(bs)) { 4928 error_setg(errp, "data-file-raw cannot be set on existing " 4929 "images"); 4930 return -EINVAL; 4931 } 4932 } else { 4933 /* if this point is reached, this probably means a new option was 4934 * added without having it covered here */ 4935 abort(); 4936 } 4937 4938 desc++; 4939 } 4940 4941 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4942 .original_status_cb = status_cb, 4943 .original_cb_opaque = cb_opaque, 4944 .total_operations = (new_version < old_version) 4945 + (s->refcount_bits != refcount_bits) 4946 }; 4947 4948 /* Upgrade first (some features may require compat=1.1) */ 4949 if (new_version > old_version) { 4950 s->qcow_version = new_version; 4951 ret = qcow2_update_header(bs); 4952 if (ret < 0) { 4953 s->qcow_version = old_version; 4954 error_setg_errno(errp, -ret, "Failed to update the image header"); 4955 return ret; 4956 } 4957 } 4958 4959 if (s->refcount_bits != refcount_bits) { 4960 int refcount_order = ctz32(refcount_bits); 4961 4962 if (new_version < 3 && refcount_bits != 16) { 4963 error_setg(errp, "Refcount widths other than 16 bits require " 4964 "compatibility level 1.1 or above (use compat=1.1 or " 4965 "greater)"); 4966 return -EINVAL; 4967 } 4968 4969 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4970 ret = qcow2_change_refcount_order(bs, refcount_order, 4971 &qcow2_amend_helper_cb, 4972 &helper_cb_info, errp); 4973 if (ret < 0) { 4974 return ret; 4975 } 4976 } 4977 4978 /* data-file-raw blocks backing files, so clear it first if requested */ 4979 if (data_file_raw) { 4980 s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW; 4981 } else { 4982 s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW; 4983 } 4984 4985 if (data_file) { 4986 g_free(s->image_data_file); 4987 s->image_data_file = *data_file ? g_strdup(data_file) : NULL; 4988 } 4989 4990 ret = qcow2_update_header(bs); 4991 if (ret < 0) { 4992 error_setg_errno(errp, -ret, "Failed to update the image header"); 4993 return ret; 4994 } 4995 4996 if (backing_file || backing_format) { 4997 ret = qcow2_change_backing_file(bs, 4998 backing_file ?: s->image_backing_file, 4999 backing_format ?: s->image_backing_format); 5000 if (ret < 0) { 5001 error_setg_errno(errp, -ret, "Failed to change the backing file"); 5002 return ret; 5003 } 5004 } 5005 5006 if (s->use_lazy_refcounts != lazy_refcounts) { 5007 if (lazy_refcounts) { 5008 if (new_version < 3) { 5009 error_setg(errp, "Lazy refcounts only supported with " 5010 "compatibility level 1.1 and above (use compat=1.1 " 5011 "or greater)"); 5012 return -EINVAL; 5013 } 5014 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 5015 ret = qcow2_update_header(bs); 5016 if (ret < 0) { 5017 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 5018 error_setg_errno(errp, -ret, "Failed to update the image header"); 5019 return ret; 5020 } 5021 s->use_lazy_refcounts = true; 5022 } else { 5023 /* make image clean first */ 5024 ret = qcow2_mark_clean(bs); 5025 if (ret < 0) { 5026 error_setg_errno(errp, -ret, "Failed to make the image clean"); 5027 return ret; 5028 } 5029 /* now disallow lazy refcounts */ 5030 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 5031 ret = qcow2_update_header(bs); 5032 if (ret < 0) { 5033 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 5034 error_setg_errno(errp, -ret, "Failed to update the image header"); 5035 return ret; 5036 } 5037 s->use_lazy_refcounts = false; 5038 } 5039 } 5040 5041 if (new_size) { 5042 BlockBackend *blk = blk_new(bdrv_get_aio_context(bs), 5043 BLK_PERM_RESIZE, BLK_PERM_ALL); 5044 ret = blk_insert_bs(blk, bs, errp); 5045 if (ret < 0) { 5046 blk_unref(blk); 5047 return ret; 5048 } 5049 5050 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp); 5051 blk_unref(blk); 5052 if (ret < 0) { 5053 return ret; 5054 } 5055 } 5056 5057 /* Downgrade last (so unsupported features can be removed before) */ 5058 if (new_version < old_version) { 5059 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 5060 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 5061 &helper_cb_info, errp); 5062 if (ret < 0) { 5063 return ret; 5064 } 5065 } 5066 5067 return 0; 5068 } 5069 5070 /* 5071 * If offset or size are negative, respectively, they will not be included in 5072 * the BLOCK_IMAGE_CORRUPTED event emitted. 5073 * fatal will be ignored for read-only BDS; corruptions found there will always 5074 * be considered non-fatal. 5075 */ 5076 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 5077 int64_t size, const char *message_format, ...) 5078 { 5079 BDRVQcow2State *s = bs->opaque; 5080 const char *node_name; 5081 char *message; 5082 va_list ap; 5083 5084 fatal = fatal && bdrv_is_writable(bs); 5085 5086 if (s->signaled_corruption && 5087 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 5088 { 5089 return; 5090 } 5091 5092 va_start(ap, message_format); 5093 message = g_strdup_vprintf(message_format, ap); 5094 va_end(ap); 5095 5096 if (fatal) { 5097 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 5098 "corruption events will be suppressed\n", message); 5099 } else { 5100 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 5101 "corruption events will be suppressed\n", message); 5102 } 5103 5104 node_name = bdrv_get_node_name(bs); 5105 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 5106 *node_name != '\0', node_name, 5107 message, offset >= 0, offset, 5108 size >= 0, size, 5109 fatal); 5110 g_free(message); 5111 5112 if (fatal) { 5113 qcow2_mark_corrupt(bs); 5114 bs->drv = NULL; /* make BDS unusable */ 5115 } 5116 5117 s->signaled_corruption = true; 5118 } 5119 5120 static QemuOptsList qcow2_create_opts = { 5121 .name = "qcow2-create-opts", 5122 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 5123 .desc = { 5124 { 5125 .name = BLOCK_OPT_SIZE, 5126 .type = QEMU_OPT_SIZE, 5127 .help = "Virtual disk size" 5128 }, 5129 { 5130 .name = BLOCK_OPT_COMPAT_LEVEL, 5131 .type = QEMU_OPT_STRING, 5132 .help = "Compatibility level (v2 [0.10] or v3 [1.1])" 5133 }, 5134 { 5135 .name = BLOCK_OPT_BACKING_FILE, 5136 .type = QEMU_OPT_STRING, 5137 .help = "File name of a base image" 5138 }, 5139 { 5140 .name = BLOCK_OPT_BACKING_FMT, 5141 .type = QEMU_OPT_STRING, 5142 .help = "Image format of the base image" 5143 }, 5144 { 5145 .name = BLOCK_OPT_DATA_FILE, 5146 .type = QEMU_OPT_STRING, 5147 .help = "File name of an external data file" 5148 }, 5149 { 5150 .name = BLOCK_OPT_DATA_FILE_RAW, 5151 .type = QEMU_OPT_BOOL, 5152 .help = "The external data file must stay valid as a raw image" 5153 }, 5154 { 5155 .name = BLOCK_OPT_ENCRYPT, 5156 .type = QEMU_OPT_BOOL, 5157 .help = "Encrypt the image with format 'aes'. (Deprecated " 5158 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 5159 }, 5160 { 5161 .name = BLOCK_OPT_ENCRYPT_FORMAT, 5162 .type = QEMU_OPT_STRING, 5163 .help = "Encrypt the image, format choices: 'aes', 'luks'", 5164 }, 5165 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 5166 "ID of secret providing qcow AES key or LUKS passphrase"), 5167 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 5168 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 5169 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 5170 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 5171 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 5172 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 5173 { 5174 .name = BLOCK_OPT_CLUSTER_SIZE, 5175 .type = QEMU_OPT_SIZE, 5176 .help = "qcow2 cluster size", 5177 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 5178 }, 5179 { 5180 .name = BLOCK_OPT_PREALLOC, 5181 .type = QEMU_OPT_STRING, 5182 .help = "Preallocation mode (allowed values: off, metadata, " 5183 "falloc, full)" 5184 }, 5185 { 5186 .name = BLOCK_OPT_LAZY_REFCOUNTS, 5187 .type = QEMU_OPT_BOOL, 5188 .help = "Postpone refcount updates", 5189 .def_value_str = "off" 5190 }, 5191 { 5192 .name = BLOCK_OPT_REFCOUNT_BITS, 5193 .type = QEMU_OPT_NUMBER, 5194 .help = "Width of a reference count entry in bits", 5195 .def_value_str = "16" 5196 }, 5197 { /* end of list */ } 5198 } 5199 }; 5200 5201 static const char *const qcow2_strong_runtime_opts[] = { 5202 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 5203 5204 NULL 5205 }; 5206 5207 BlockDriver bdrv_qcow2 = { 5208 .format_name = "qcow2", 5209 .instance_size = sizeof(BDRVQcow2State), 5210 .bdrv_probe = qcow2_probe, 5211 .bdrv_open = qcow2_open, 5212 .bdrv_close = qcow2_close, 5213 .bdrv_reopen_prepare = qcow2_reopen_prepare, 5214 .bdrv_reopen_commit = qcow2_reopen_commit, 5215 .bdrv_reopen_abort = qcow2_reopen_abort, 5216 .bdrv_join_options = qcow2_join_options, 5217 .bdrv_child_perm = bdrv_format_default_perms, 5218 .bdrv_co_create_opts = qcow2_co_create_opts, 5219 .bdrv_co_create = qcow2_co_create, 5220 .bdrv_has_zero_init = qcow2_has_zero_init, 5221 .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1, 5222 .bdrv_co_block_status = qcow2_co_block_status, 5223 5224 .bdrv_co_preadv_part = qcow2_co_preadv_part, 5225 .bdrv_co_pwritev_part = qcow2_co_pwritev_part, 5226 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 5227 5228 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 5229 .bdrv_co_pdiscard = qcow2_co_pdiscard, 5230 .bdrv_co_copy_range_from = qcow2_co_copy_range_from, 5231 .bdrv_co_copy_range_to = qcow2_co_copy_range_to, 5232 .bdrv_co_truncate = qcow2_co_truncate, 5233 .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part, 5234 .bdrv_make_empty = qcow2_make_empty, 5235 5236 .bdrv_snapshot_create = qcow2_snapshot_create, 5237 .bdrv_snapshot_goto = qcow2_snapshot_goto, 5238 .bdrv_snapshot_delete = qcow2_snapshot_delete, 5239 .bdrv_snapshot_list = qcow2_snapshot_list, 5240 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 5241 .bdrv_measure = qcow2_measure, 5242 .bdrv_get_info = qcow2_get_info, 5243 .bdrv_get_specific_info = qcow2_get_specific_info, 5244 5245 .bdrv_save_vmstate = qcow2_save_vmstate, 5246 .bdrv_load_vmstate = qcow2_load_vmstate, 5247 5248 .supports_backing = true, 5249 .bdrv_change_backing_file = qcow2_change_backing_file, 5250 5251 .bdrv_refresh_limits = qcow2_refresh_limits, 5252 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, 5253 .bdrv_inactivate = qcow2_inactivate, 5254 5255 .create_opts = &qcow2_create_opts, 5256 .strong_runtime_opts = qcow2_strong_runtime_opts, 5257 .mutable_opts = mutable_opts, 5258 .bdrv_co_check = qcow2_co_check, 5259 .bdrv_amend_options = qcow2_amend_options, 5260 5261 .bdrv_detach_aio_context = qcow2_detach_aio_context, 5262 .bdrv_attach_aio_context = qcow2_attach_aio_context, 5263 5264 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 5265 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 5266 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 5267 }; 5268 5269 static void bdrv_qcow2_init(void) 5270 { 5271 bdrv_register(&bdrv_qcow2); 5272 } 5273 5274 block_init(bdrv_qcow2_init); 5275