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 #include "block/aio_task.h" 45 46 /* 47 Differences with QCOW: 48 49 - Support for multiple incremental snapshots. 50 - Memory management by reference counts. 51 - Clusters which have a reference count of one have the bit 52 QCOW_OFLAG_COPIED to optimize write performance. 53 - Size of compressed clusters is stored in sectors to reduce bit usage 54 in the cluster offsets. 55 - Support for storing additional data (such as the VM state) in the 56 snapshots. 57 - If a backing store is used, the cluster size is not constrained 58 (could be backported to QCOW). 59 - L2 tables have always a size of one cluster. 60 */ 61 62 63 typedef struct { 64 uint32_t magic; 65 uint32_t len; 66 } QEMU_PACKED QCowExtension; 67 68 #define QCOW2_EXT_MAGIC_END 0 69 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 70 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 71 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 72 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 73 #define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441 74 75 static int coroutine_fn 76 qcow2_co_preadv_compressed(BlockDriverState *bs, 77 uint64_t file_cluster_offset, 78 uint64_t offset, 79 uint64_t bytes, 80 QEMUIOVector *qiov, 81 size_t qiov_offset); 82 83 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 84 { 85 const QCowHeader *cow_header = (const void *)buf; 86 87 if (buf_size >= sizeof(QCowHeader) && 88 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 89 be32_to_cpu(cow_header->version) >= 2) 90 return 100; 91 else 92 return 0; 93 } 94 95 96 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 97 uint8_t *buf, size_t buflen, 98 void *opaque, Error **errp) 99 { 100 BlockDriverState *bs = opaque; 101 BDRVQcow2State *s = bs->opaque; 102 ssize_t ret; 103 104 if ((offset + buflen) > s->crypto_header.length) { 105 error_setg(errp, "Request for data outside of extension header"); 106 return -1; 107 } 108 109 ret = bdrv_pread(bs->file, 110 s->crypto_header.offset + offset, buf, buflen); 111 if (ret < 0) { 112 error_setg_errno(errp, -ret, "Could not read encryption header"); 113 return -1; 114 } 115 return ret; 116 } 117 118 119 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 120 void *opaque, Error **errp) 121 { 122 BlockDriverState *bs = opaque; 123 BDRVQcow2State *s = bs->opaque; 124 int64_t ret; 125 int64_t clusterlen; 126 127 ret = qcow2_alloc_clusters(bs, headerlen); 128 if (ret < 0) { 129 error_setg_errno(errp, -ret, 130 "Cannot allocate cluster for LUKS header size %zu", 131 headerlen); 132 return -1; 133 } 134 135 s->crypto_header.length = headerlen; 136 s->crypto_header.offset = ret; 137 138 /* Zero fill remaining space in cluster so it has predictable 139 * content in case of future spec changes */ 140 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 141 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0); 142 ret = bdrv_pwrite_zeroes(bs->file, 143 ret + headerlen, 144 clusterlen - headerlen, 0); 145 if (ret < 0) { 146 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 147 return -1; 148 } 149 150 return ret; 151 } 152 153 154 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 155 const uint8_t *buf, size_t buflen, 156 void *opaque, Error **errp) 157 { 158 BlockDriverState *bs = opaque; 159 BDRVQcow2State *s = bs->opaque; 160 ssize_t ret; 161 162 if ((offset + buflen) > s->crypto_header.length) { 163 error_setg(errp, "Request for data outside of extension header"); 164 return -1; 165 } 166 167 ret = bdrv_pwrite(bs->file, 168 s->crypto_header.offset + offset, buf, buflen); 169 if (ret < 0) { 170 error_setg_errno(errp, -ret, "Could not read encryption header"); 171 return -1; 172 } 173 return ret; 174 } 175 176 177 /* 178 * read qcow2 extension and fill bs 179 * start reading from start_offset 180 * finish reading upon magic of value 0 or when end_offset reached 181 * unknown magic is skipped (future extension this version knows nothing about) 182 * return 0 upon success, non-0 otherwise 183 */ 184 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 185 uint64_t end_offset, void **p_feature_table, 186 int flags, bool *need_update_header, 187 Error **errp) 188 { 189 BDRVQcow2State *s = bs->opaque; 190 QCowExtension ext; 191 uint64_t offset; 192 int ret; 193 Qcow2BitmapHeaderExt bitmaps_ext; 194 195 if (need_update_header != NULL) { 196 *need_update_header = false; 197 } 198 199 #ifdef DEBUG_EXT 200 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 201 #endif 202 offset = start_offset; 203 while (offset < end_offset) { 204 205 #ifdef DEBUG_EXT 206 /* Sanity check */ 207 if (offset > s->cluster_size) 208 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 209 210 printf("attempting to read extended header in offset %lu\n", offset); 211 #endif 212 213 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 214 if (ret < 0) { 215 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 216 "pread fail from offset %" PRIu64, offset); 217 return 1; 218 } 219 ext.magic = be32_to_cpu(ext.magic); 220 ext.len = be32_to_cpu(ext.len); 221 offset += sizeof(ext); 222 #ifdef DEBUG_EXT 223 printf("ext.magic = 0x%x\n", ext.magic); 224 #endif 225 if (offset > end_offset || ext.len > end_offset - offset) { 226 error_setg(errp, "Header extension too large"); 227 return -EINVAL; 228 } 229 230 switch (ext.magic) { 231 case QCOW2_EXT_MAGIC_END: 232 return 0; 233 234 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 235 if (ext.len >= sizeof(bs->backing_format)) { 236 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 237 " too large (>=%zu)", ext.len, 238 sizeof(bs->backing_format)); 239 return 2; 240 } 241 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 242 if (ret < 0) { 243 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 244 "Could not read format name"); 245 return 3; 246 } 247 bs->backing_format[ext.len] = '\0'; 248 s->image_backing_format = g_strdup(bs->backing_format); 249 #ifdef DEBUG_EXT 250 printf("Qcow2: Got format extension %s\n", bs->backing_format); 251 #endif 252 break; 253 254 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 255 if (p_feature_table != NULL) { 256 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 257 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 258 if (ret < 0) { 259 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 260 "Could not read table"); 261 return ret; 262 } 263 264 *p_feature_table = feature_table; 265 } 266 break; 267 268 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 269 unsigned int cflags = 0; 270 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 271 error_setg(errp, "CRYPTO header extension only " 272 "expected with LUKS encryption method"); 273 return -EINVAL; 274 } 275 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 276 error_setg(errp, "CRYPTO header extension size %u, " 277 "but expected size %zu", ext.len, 278 sizeof(Qcow2CryptoHeaderExtension)); 279 return -EINVAL; 280 } 281 282 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 283 if (ret < 0) { 284 error_setg_errno(errp, -ret, 285 "Unable to read CRYPTO header extension"); 286 return ret; 287 } 288 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 289 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 290 291 if ((s->crypto_header.offset % s->cluster_size) != 0) { 292 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 293 "not a multiple of cluster size '%u'", 294 s->crypto_header.offset, s->cluster_size); 295 return -EINVAL; 296 } 297 298 if (flags & BDRV_O_NO_IO) { 299 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 300 } 301 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 302 qcow2_crypto_hdr_read_func, 303 bs, cflags, QCOW2_MAX_THREADS, errp); 304 if (!s->crypto) { 305 return -EINVAL; 306 } 307 } break; 308 309 case QCOW2_EXT_MAGIC_BITMAPS: 310 if (ext.len != sizeof(bitmaps_ext)) { 311 error_setg_errno(errp, -ret, "bitmaps_ext: " 312 "Invalid extension length"); 313 return -EINVAL; 314 } 315 316 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 317 if (s->qcow_version < 3) { 318 /* Let's be a bit more specific */ 319 warn_report("This qcow2 v2 image contains bitmaps, but " 320 "they may have been modified by a program " 321 "without persistent bitmap support; so now " 322 "they must all be considered inconsistent"); 323 } else { 324 warn_report("a program lacking bitmap support " 325 "modified this file, so all bitmaps are now " 326 "considered inconsistent"); 327 } 328 error_printf("Some clusters may be leaked, " 329 "run 'qemu-img check -r' on the image " 330 "file to fix."); 331 if (need_update_header != NULL) { 332 /* Updating is needed to drop invalid bitmap extension. */ 333 *need_update_header = true; 334 } 335 break; 336 } 337 338 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 339 if (ret < 0) { 340 error_setg_errno(errp, -ret, "bitmaps_ext: " 341 "Could not read ext header"); 342 return ret; 343 } 344 345 if (bitmaps_ext.reserved32 != 0) { 346 error_setg_errno(errp, -ret, "bitmaps_ext: " 347 "Reserved field is not zero"); 348 return -EINVAL; 349 } 350 351 bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps); 352 bitmaps_ext.bitmap_directory_size = 353 be64_to_cpu(bitmaps_ext.bitmap_directory_size); 354 bitmaps_ext.bitmap_directory_offset = 355 be64_to_cpu(bitmaps_ext.bitmap_directory_offset); 356 357 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 358 error_setg(errp, 359 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 360 "exceeding the QEMU supported maximum of %d", 361 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 362 return -EINVAL; 363 } 364 365 if (bitmaps_ext.nb_bitmaps == 0) { 366 error_setg(errp, "found bitmaps extension with zero bitmaps"); 367 return -EINVAL; 368 } 369 370 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 371 error_setg(errp, "bitmaps_ext: " 372 "invalid bitmap directory offset"); 373 return -EINVAL; 374 } 375 376 if (bitmaps_ext.bitmap_directory_size > 377 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 378 error_setg(errp, "bitmaps_ext: " 379 "bitmap directory size (%" PRIu64 ") exceeds " 380 "the maximum supported size (%d)", 381 bitmaps_ext.bitmap_directory_size, 382 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 383 return -EINVAL; 384 } 385 386 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 387 s->bitmap_directory_offset = 388 bitmaps_ext.bitmap_directory_offset; 389 s->bitmap_directory_size = 390 bitmaps_ext.bitmap_directory_size; 391 392 #ifdef DEBUG_EXT 393 printf("Qcow2: Got bitmaps extension: " 394 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 395 s->bitmap_directory_offset, s->nb_bitmaps); 396 #endif 397 break; 398 399 case QCOW2_EXT_MAGIC_DATA_FILE: 400 { 401 s->image_data_file = g_malloc0(ext.len + 1); 402 ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len); 403 if (ret < 0) { 404 error_setg_errno(errp, -ret, 405 "ERROR: Could not read data file name"); 406 return ret; 407 } 408 #ifdef DEBUG_EXT 409 printf("Qcow2: Got external data file %s\n", s->image_data_file); 410 #endif 411 break; 412 } 413 414 default: 415 /* unknown magic - save it in case we need to rewrite the header */ 416 /* If you add a new feature, make sure to also update the fast 417 * path of qcow2_make_empty() to deal with it. */ 418 { 419 Qcow2UnknownHeaderExtension *uext; 420 421 uext = g_malloc0(sizeof(*uext) + ext.len); 422 uext->magic = ext.magic; 423 uext->len = ext.len; 424 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 425 426 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 427 if (ret < 0) { 428 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 429 "Could not read data"); 430 return ret; 431 } 432 } 433 break; 434 } 435 436 offset += ((ext.len + 7) & ~7); 437 } 438 439 return 0; 440 } 441 442 static void cleanup_unknown_header_ext(BlockDriverState *bs) 443 { 444 BDRVQcow2State *s = bs->opaque; 445 Qcow2UnknownHeaderExtension *uext, *next; 446 447 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 448 QLIST_REMOVE(uext, next); 449 g_free(uext); 450 } 451 } 452 453 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 454 uint64_t mask) 455 { 456 char *features = g_strdup(""); 457 char *old; 458 459 while (table && table->name[0] != '\0') { 460 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 461 if (mask & (1ULL << table->bit)) { 462 old = features; 463 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 464 table->name); 465 g_free(old); 466 mask &= ~(1ULL << table->bit); 467 } 468 } 469 table++; 470 } 471 472 if (mask) { 473 old = features; 474 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 475 old, *old ? ", " : "", mask); 476 g_free(old); 477 } 478 479 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 480 g_free(features); 481 } 482 483 /* 484 * Sets the dirty bit and flushes afterwards if necessary. 485 * 486 * The incompatible_features bit is only set if the image file header was 487 * updated successfully. Therefore it is not required to check the return 488 * value of this function. 489 */ 490 int qcow2_mark_dirty(BlockDriverState *bs) 491 { 492 BDRVQcow2State *s = bs->opaque; 493 uint64_t val; 494 int ret; 495 496 assert(s->qcow_version >= 3); 497 498 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 499 return 0; /* already dirty */ 500 } 501 502 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 503 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 504 &val, sizeof(val)); 505 if (ret < 0) { 506 return ret; 507 } 508 ret = bdrv_flush(bs->file->bs); 509 if (ret < 0) { 510 return ret; 511 } 512 513 /* Only treat image as dirty if the header was updated successfully */ 514 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 515 return 0; 516 } 517 518 /* 519 * Clears the dirty bit and flushes before if necessary. Only call this 520 * function when there are no pending requests, it does not guard against 521 * concurrent requests dirtying the image. 522 */ 523 static int qcow2_mark_clean(BlockDriverState *bs) 524 { 525 BDRVQcow2State *s = bs->opaque; 526 527 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 528 int ret; 529 530 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 531 532 ret = qcow2_flush_caches(bs); 533 if (ret < 0) { 534 return ret; 535 } 536 537 return qcow2_update_header(bs); 538 } 539 return 0; 540 } 541 542 /* 543 * Marks the image as corrupt. 544 */ 545 int qcow2_mark_corrupt(BlockDriverState *bs) 546 { 547 BDRVQcow2State *s = bs->opaque; 548 549 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 550 return qcow2_update_header(bs); 551 } 552 553 /* 554 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 555 * before if necessary. 556 */ 557 int qcow2_mark_consistent(BlockDriverState *bs) 558 { 559 BDRVQcow2State *s = bs->opaque; 560 561 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 562 int ret = qcow2_flush_caches(bs); 563 if (ret < 0) { 564 return ret; 565 } 566 567 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 568 return qcow2_update_header(bs); 569 } 570 return 0; 571 } 572 573 static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, 574 BdrvCheckResult *result, 575 BdrvCheckMode fix) 576 { 577 int ret = qcow2_check_refcounts(bs, result, fix); 578 if (ret < 0) { 579 return ret; 580 } 581 582 if (fix && result->check_errors == 0 && result->corruptions == 0) { 583 ret = qcow2_mark_clean(bs); 584 if (ret < 0) { 585 return ret; 586 } 587 return qcow2_mark_consistent(bs); 588 } 589 return ret; 590 } 591 592 static int coroutine_fn qcow2_co_check(BlockDriverState *bs, 593 BdrvCheckResult *result, 594 BdrvCheckMode fix) 595 { 596 BDRVQcow2State *s = bs->opaque; 597 int ret; 598 599 qemu_co_mutex_lock(&s->lock); 600 ret = qcow2_co_check_locked(bs, result, fix); 601 qemu_co_mutex_unlock(&s->lock); 602 return ret; 603 } 604 605 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, 606 uint64_t entries, size_t entry_len, 607 int64_t max_size_bytes, const char *table_name, 608 Error **errp) 609 { 610 BDRVQcow2State *s = bs->opaque; 611 612 if (entries > max_size_bytes / entry_len) { 613 error_setg(errp, "%s too large", table_name); 614 return -EFBIG; 615 } 616 617 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 618 * because values will be passed to qemu functions taking int64_t. */ 619 if ((INT64_MAX - entries * entry_len < offset) || 620 (offset_into_cluster(s, offset) != 0)) { 621 error_setg(errp, "%s offset invalid", table_name); 622 return -EINVAL; 623 } 624 625 return 0; 626 } 627 628 static const char *const mutable_opts[] = { 629 QCOW2_OPT_LAZY_REFCOUNTS, 630 QCOW2_OPT_DISCARD_REQUEST, 631 QCOW2_OPT_DISCARD_SNAPSHOT, 632 QCOW2_OPT_DISCARD_OTHER, 633 QCOW2_OPT_OVERLAP, 634 QCOW2_OPT_OVERLAP_TEMPLATE, 635 QCOW2_OPT_OVERLAP_MAIN_HEADER, 636 QCOW2_OPT_OVERLAP_ACTIVE_L1, 637 QCOW2_OPT_OVERLAP_ACTIVE_L2, 638 QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 639 QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 640 QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 641 QCOW2_OPT_OVERLAP_INACTIVE_L1, 642 QCOW2_OPT_OVERLAP_INACTIVE_L2, 643 QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 644 QCOW2_OPT_CACHE_SIZE, 645 QCOW2_OPT_L2_CACHE_SIZE, 646 QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 647 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 648 QCOW2_OPT_CACHE_CLEAN_INTERVAL, 649 NULL 650 }; 651 652 static QemuOptsList qcow2_runtime_opts = { 653 .name = "qcow2", 654 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 655 .desc = { 656 { 657 .name = QCOW2_OPT_LAZY_REFCOUNTS, 658 .type = QEMU_OPT_BOOL, 659 .help = "Postpone refcount updates", 660 }, 661 { 662 .name = QCOW2_OPT_DISCARD_REQUEST, 663 .type = QEMU_OPT_BOOL, 664 .help = "Pass guest discard requests to the layer below", 665 }, 666 { 667 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 668 .type = QEMU_OPT_BOOL, 669 .help = "Generate discard requests when snapshot related space " 670 "is freed", 671 }, 672 { 673 .name = QCOW2_OPT_DISCARD_OTHER, 674 .type = QEMU_OPT_BOOL, 675 .help = "Generate discard requests when other clusters are freed", 676 }, 677 { 678 .name = QCOW2_OPT_OVERLAP, 679 .type = QEMU_OPT_STRING, 680 .help = "Selects which overlap checks to perform from a range of " 681 "templates (none, constant, cached, all)", 682 }, 683 { 684 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 685 .type = QEMU_OPT_STRING, 686 .help = "Selects which overlap checks to perform from a range of " 687 "templates (none, constant, cached, all)", 688 }, 689 { 690 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 691 .type = QEMU_OPT_BOOL, 692 .help = "Check for unintended writes into the main qcow2 header", 693 }, 694 { 695 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 696 .type = QEMU_OPT_BOOL, 697 .help = "Check for unintended writes into the active L1 table", 698 }, 699 { 700 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 701 .type = QEMU_OPT_BOOL, 702 .help = "Check for unintended writes into an active L2 table", 703 }, 704 { 705 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 706 .type = QEMU_OPT_BOOL, 707 .help = "Check for unintended writes into the refcount table", 708 }, 709 { 710 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 711 .type = QEMU_OPT_BOOL, 712 .help = "Check for unintended writes into a refcount block", 713 }, 714 { 715 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 716 .type = QEMU_OPT_BOOL, 717 .help = "Check for unintended writes into the snapshot table", 718 }, 719 { 720 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 721 .type = QEMU_OPT_BOOL, 722 .help = "Check for unintended writes into an inactive L1 table", 723 }, 724 { 725 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 726 .type = QEMU_OPT_BOOL, 727 .help = "Check for unintended writes into an inactive L2 table", 728 }, 729 { 730 .name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 731 .type = QEMU_OPT_BOOL, 732 .help = "Check for unintended writes into the bitmap directory", 733 }, 734 { 735 .name = QCOW2_OPT_CACHE_SIZE, 736 .type = QEMU_OPT_SIZE, 737 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 738 "cache size", 739 }, 740 { 741 .name = QCOW2_OPT_L2_CACHE_SIZE, 742 .type = QEMU_OPT_SIZE, 743 .help = "Maximum L2 table cache size", 744 }, 745 { 746 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 747 .type = QEMU_OPT_SIZE, 748 .help = "Size of each entry in the L2 cache", 749 }, 750 { 751 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 752 .type = QEMU_OPT_SIZE, 753 .help = "Maximum refcount block cache size", 754 }, 755 { 756 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 757 .type = QEMU_OPT_NUMBER, 758 .help = "Clean unused cache entries after this time (in seconds)", 759 }, 760 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 761 "ID of secret providing qcow2 AES key or LUKS passphrase"), 762 { /* end of list */ } 763 }, 764 }; 765 766 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 767 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 768 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 769 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 770 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 771 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 772 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 773 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 774 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 775 [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 776 }; 777 778 static void cache_clean_timer_cb(void *opaque) 779 { 780 BlockDriverState *bs = opaque; 781 BDRVQcow2State *s = bs->opaque; 782 qcow2_cache_clean_unused(s->l2_table_cache); 783 qcow2_cache_clean_unused(s->refcount_block_cache); 784 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 785 (int64_t) s->cache_clean_interval * 1000); 786 } 787 788 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 789 { 790 BDRVQcow2State *s = bs->opaque; 791 if (s->cache_clean_interval > 0) { 792 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 793 SCALE_MS, cache_clean_timer_cb, 794 bs); 795 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 796 (int64_t) s->cache_clean_interval * 1000); 797 } 798 } 799 800 static void cache_clean_timer_del(BlockDriverState *bs) 801 { 802 BDRVQcow2State *s = bs->opaque; 803 if (s->cache_clean_timer) { 804 timer_del(s->cache_clean_timer); 805 timer_free(s->cache_clean_timer); 806 s->cache_clean_timer = NULL; 807 } 808 } 809 810 static void qcow2_detach_aio_context(BlockDriverState *bs) 811 { 812 cache_clean_timer_del(bs); 813 } 814 815 static void qcow2_attach_aio_context(BlockDriverState *bs, 816 AioContext *new_context) 817 { 818 cache_clean_timer_init(bs, new_context); 819 } 820 821 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 822 uint64_t *l2_cache_size, 823 uint64_t *l2_cache_entry_size, 824 uint64_t *refcount_cache_size, Error **errp) 825 { 826 BDRVQcow2State *s = bs->opaque; 827 uint64_t combined_cache_size, l2_cache_max_setting; 828 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 829 bool l2_cache_entry_size_set; 830 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; 831 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; 832 uint64_t max_l2_entries = DIV_ROUND_UP(virtual_disk_size, s->cluster_size); 833 /* An L2 table is always one cluster in size so the max cache size 834 * should be a multiple of the cluster size. */ 835 uint64_t max_l2_cache = ROUND_UP(max_l2_entries * sizeof(uint64_t), 836 s->cluster_size); 837 838 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 839 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 840 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 841 l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE); 842 843 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 844 l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 845 DEFAULT_L2_CACHE_MAX_SIZE); 846 *refcount_cache_size = qemu_opt_get_size(opts, 847 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 848 849 *l2_cache_entry_size = qemu_opt_get_size( 850 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 851 852 *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting); 853 854 if (combined_cache_size_set) { 855 if (l2_cache_size_set && refcount_cache_size_set) { 856 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 857 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 858 "at the same time"); 859 return; 860 } else if (l2_cache_size_set && 861 (l2_cache_max_setting > combined_cache_size)) { 862 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 863 QCOW2_OPT_CACHE_SIZE); 864 return; 865 } else if (*refcount_cache_size > combined_cache_size) { 866 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 867 QCOW2_OPT_CACHE_SIZE); 868 return; 869 } 870 871 if (l2_cache_size_set) { 872 *refcount_cache_size = combined_cache_size - *l2_cache_size; 873 } else if (refcount_cache_size_set) { 874 *l2_cache_size = combined_cache_size - *refcount_cache_size; 875 } else { 876 /* Assign as much memory as possible to the L2 cache, and 877 * use the remainder for the refcount cache */ 878 if (combined_cache_size >= max_l2_cache + min_refcount_cache) { 879 *l2_cache_size = max_l2_cache; 880 *refcount_cache_size = combined_cache_size - *l2_cache_size; 881 } else { 882 *refcount_cache_size = 883 MIN(combined_cache_size, min_refcount_cache); 884 *l2_cache_size = combined_cache_size - *refcount_cache_size; 885 } 886 } 887 } 888 889 /* 890 * If the L2 cache is not enough to cover the whole disk then 891 * default to 4KB entries. Smaller entries reduce the cost of 892 * loads and evictions and increase I/O performance. 893 */ 894 if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) { 895 *l2_cache_entry_size = MIN(s->cluster_size, 4096); 896 } 897 898 /* l2_cache_size and refcount_cache_size are ensured to have at least 899 * their minimum values in qcow2_update_options_prepare() */ 900 901 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 902 *l2_cache_entry_size > s->cluster_size || 903 !is_power_of_2(*l2_cache_entry_size)) { 904 error_setg(errp, "L2 cache entry size must be a power of two " 905 "between %d and the cluster size (%d)", 906 1 << MIN_CLUSTER_BITS, s->cluster_size); 907 return; 908 } 909 } 910 911 typedef struct Qcow2ReopenState { 912 Qcow2Cache *l2_table_cache; 913 Qcow2Cache *refcount_block_cache; 914 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 915 bool use_lazy_refcounts; 916 int overlap_check; 917 bool discard_passthrough[QCOW2_DISCARD_MAX]; 918 uint64_t cache_clean_interval; 919 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 920 } Qcow2ReopenState; 921 922 static int qcow2_update_options_prepare(BlockDriverState *bs, 923 Qcow2ReopenState *r, 924 QDict *options, int flags, 925 Error **errp) 926 { 927 BDRVQcow2State *s = bs->opaque; 928 QemuOpts *opts = NULL; 929 const char *opt_overlap_check, *opt_overlap_check_template; 930 int overlap_check_template = 0; 931 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 932 int i; 933 const char *encryptfmt; 934 QDict *encryptopts = NULL; 935 Error *local_err = NULL; 936 int ret; 937 938 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 939 encryptfmt = qdict_get_try_str(encryptopts, "format"); 940 941 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 942 qemu_opts_absorb_qdict(opts, options, &local_err); 943 if (local_err) { 944 error_propagate(errp, local_err); 945 ret = -EINVAL; 946 goto fail; 947 } 948 949 /* get L2 table/refcount block cache size from command line options */ 950 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 951 &refcount_cache_size, &local_err); 952 if (local_err) { 953 error_propagate(errp, local_err); 954 ret = -EINVAL; 955 goto fail; 956 } 957 958 l2_cache_size /= l2_cache_entry_size; 959 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 960 l2_cache_size = MIN_L2_CACHE_SIZE; 961 } 962 if (l2_cache_size > INT_MAX) { 963 error_setg(errp, "L2 cache size too big"); 964 ret = -EINVAL; 965 goto fail; 966 } 967 968 refcount_cache_size /= s->cluster_size; 969 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 970 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 971 } 972 if (refcount_cache_size > INT_MAX) { 973 error_setg(errp, "Refcount cache size too big"); 974 ret = -EINVAL; 975 goto fail; 976 } 977 978 /* alloc new L2 table/refcount block cache, flush old one */ 979 if (s->l2_table_cache) { 980 ret = qcow2_cache_flush(bs, s->l2_table_cache); 981 if (ret) { 982 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 983 goto fail; 984 } 985 } 986 987 if (s->refcount_block_cache) { 988 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 989 if (ret) { 990 error_setg_errno(errp, -ret, 991 "Failed to flush the refcount block cache"); 992 goto fail; 993 } 994 } 995 996 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 997 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 998 l2_cache_entry_size); 999 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 1000 s->cluster_size); 1001 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 1002 error_setg(errp, "Could not allocate metadata caches"); 1003 ret = -ENOMEM; 1004 goto fail; 1005 } 1006 1007 /* New interval for cache cleanup timer */ 1008 r->cache_clean_interval = 1009 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 1010 DEFAULT_CACHE_CLEAN_INTERVAL); 1011 #ifndef CONFIG_LINUX 1012 if (r->cache_clean_interval != 0) { 1013 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 1014 " not supported on this host"); 1015 ret = -EINVAL; 1016 goto fail; 1017 } 1018 #endif 1019 if (r->cache_clean_interval > UINT_MAX) { 1020 error_setg(errp, "Cache clean interval too big"); 1021 ret = -EINVAL; 1022 goto fail; 1023 } 1024 1025 /* lazy-refcounts; flush if going from enabled to disabled */ 1026 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 1027 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 1028 if (r->use_lazy_refcounts && s->qcow_version < 3) { 1029 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 1030 "qemu 1.1 compatibility level"); 1031 ret = -EINVAL; 1032 goto fail; 1033 } 1034 1035 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 1036 ret = qcow2_mark_clean(bs); 1037 if (ret < 0) { 1038 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 1039 goto fail; 1040 } 1041 } 1042 1043 /* Overlap check options */ 1044 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 1045 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 1046 if (opt_overlap_check_template && opt_overlap_check && 1047 strcmp(opt_overlap_check_template, opt_overlap_check)) 1048 { 1049 error_setg(errp, "Conflicting values for qcow2 options '" 1050 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 1051 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 1052 ret = -EINVAL; 1053 goto fail; 1054 } 1055 if (!opt_overlap_check) { 1056 opt_overlap_check = opt_overlap_check_template ?: "cached"; 1057 } 1058 1059 if (!strcmp(opt_overlap_check, "none")) { 1060 overlap_check_template = 0; 1061 } else if (!strcmp(opt_overlap_check, "constant")) { 1062 overlap_check_template = QCOW2_OL_CONSTANT; 1063 } else if (!strcmp(opt_overlap_check, "cached")) { 1064 overlap_check_template = QCOW2_OL_CACHED; 1065 } else if (!strcmp(opt_overlap_check, "all")) { 1066 overlap_check_template = QCOW2_OL_ALL; 1067 } else { 1068 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1069 "'overlap-check'. Allowed are any of the following: " 1070 "none, constant, cached, all", opt_overlap_check); 1071 ret = -EINVAL; 1072 goto fail; 1073 } 1074 1075 r->overlap_check = 0; 1076 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1077 /* overlap-check defines a template bitmask, but every flag may be 1078 * overwritten through the associated boolean option */ 1079 r->overlap_check |= 1080 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1081 overlap_check_template & (1 << i)) << i; 1082 } 1083 1084 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 1085 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1086 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1087 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1088 flags & BDRV_O_UNMAP); 1089 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1090 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1091 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1092 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1093 1094 switch (s->crypt_method_header) { 1095 case QCOW_CRYPT_NONE: 1096 if (encryptfmt) { 1097 error_setg(errp, "No encryption in image header, but options " 1098 "specified format '%s'", encryptfmt); 1099 ret = -EINVAL; 1100 goto fail; 1101 } 1102 break; 1103 1104 case QCOW_CRYPT_AES: 1105 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1106 error_setg(errp, 1107 "Header reported 'aes' encryption format but " 1108 "options specify '%s'", encryptfmt); 1109 ret = -EINVAL; 1110 goto fail; 1111 } 1112 qdict_put_str(encryptopts, "format", "qcow"); 1113 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1114 break; 1115 1116 case QCOW_CRYPT_LUKS: 1117 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1118 error_setg(errp, 1119 "Header reported 'luks' encryption format but " 1120 "options specify '%s'", encryptfmt); 1121 ret = -EINVAL; 1122 goto fail; 1123 } 1124 qdict_put_str(encryptopts, "format", "luks"); 1125 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1126 break; 1127 1128 default: 1129 error_setg(errp, "Unsupported encryption method %d", 1130 s->crypt_method_header); 1131 break; 1132 } 1133 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1134 ret = -EINVAL; 1135 goto fail; 1136 } 1137 1138 ret = 0; 1139 fail: 1140 qobject_unref(encryptopts); 1141 qemu_opts_del(opts); 1142 opts = NULL; 1143 return ret; 1144 } 1145 1146 static void qcow2_update_options_commit(BlockDriverState *bs, 1147 Qcow2ReopenState *r) 1148 { 1149 BDRVQcow2State *s = bs->opaque; 1150 int i; 1151 1152 if (s->l2_table_cache) { 1153 qcow2_cache_destroy(s->l2_table_cache); 1154 } 1155 if (s->refcount_block_cache) { 1156 qcow2_cache_destroy(s->refcount_block_cache); 1157 } 1158 s->l2_table_cache = r->l2_table_cache; 1159 s->refcount_block_cache = r->refcount_block_cache; 1160 s->l2_slice_size = r->l2_slice_size; 1161 1162 s->overlap_check = r->overlap_check; 1163 s->use_lazy_refcounts = r->use_lazy_refcounts; 1164 1165 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1166 s->discard_passthrough[i] = r->discard_passthrough[i]; 1167 } 1168 1169 if (s->cache_clean_interval != r->cache_clean_interval) { 1170 cache_clean_timer_del(bs); 1171 s->cache_clean_interval = r->cache_clean_interval; 1172 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1173 } 1174 1175 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1176 s->crypto_opts = r->crypto_opts; 1177 } 1178 1179 static void qcow2_update_options_abort(BlockDriverState *bs, 1180 Qcow2ReopenState *r) 1181 { 1182 if (r->l2_table_cache) { 1183 qcow2_cache_destroy(r->l2_table_cache); 1184 } 1185 if (r->refcount_block_cache) { 1186 qcow2_cache_destroy(r->refcount_block_cache); 1187 } 1188 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1189 } 1190 1191 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1192 int flags, Error **errp) 1193 { 1194 Qcow2ReopenState r = {}; 1195 int ret; 1196 1197 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1198 if (ret >= 0) { 1199 qcow2_update_options_commit(bs, &r); 1200 } else { 1201 qcow2_update_options_abort(bs, &r); 1202 } 1203 1204 return ret; 1205 } 1206 1207 /* Called with s->lock held. */ 1208 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, 1209 int flags, Error **errp) 1210 { 1211 BDRVQcow2State *s = bs->opaque; 1212 unsigned int len, i; 1213 int ret = 0; 1214 QCowHeader header; 1215 Error *local_err = NULL; 1216 uint64_t ext_end; 1217 uint64_t l1_vm_state_index; 1218 bool update_header = false; 1219 1220 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1221 if (ret < 0) { 1222 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1223 goto fail; 1224 } 1225 header.magic = be32_to_cpu(header.magic); 1226 header.version = be32_to_cpu(header.version); 1227 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 1228 header.backing_file_size = be32_to_cpu(header.backing_file_size); 1229 header.size = be64_to_cpu(header.size); 1230 header.cluster_bits = be32_to_cpu(header.cluster_bits); 1231 header.crypt_method = be32_to_cpu(header.crypt_method); 1232 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 1233 header.l1_size = be32_to_cpu(header.l1_size); 1234 header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset); 1235 header.refcount_table_clusters = 1236 be32_to_cpu(header.refcount_table_clusters); 1237 header.snapshots_offset = be64_to_cpu(header.snapshots_offset); 1238 header.nb_snapshots = be32_to_cpu(header.nb_snapshots); 1239 1240 if (header.magic != QCOW_MAGIC) { 1241 error_setg(errp, "Image is not in qcow2 format"); 1242 ret = -EINVAL; 1243 goto fail; 1244 } 1245 if (header.version < 2 || header.version > 3) { 1246 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1247 ret = -ENOTSUP; 1248 goto fail; 1249 } 1250 1251 s->qcow_version = header.version; 1252 1253 /* Initialise cluster size */ 1254 if (header.cluster_bits < MIN_CLUSTER_BITS || 1255 header.cluster_bits > MAX_CLUSTER_BITS) { 1256 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1257 header.cluster_bits); 1258 ret = -EINVAL; 1259 goto fail; 1260 } 1261 1262 s->cluster_bits = header.cluster_bits; 1263 s->cluster_size = 1 << s->cluster_bits; 1264 1265 /* Initialise version 3 header fields */ 1266 if (header.version == 2) { 1267 header.incompatible_features = 0; 1268 header.compatible_features = 0; 1269 header.autoclear_features = 0; 1270 header.refcount_order = 4; 1271 header.header_length = 72; 1272 } else { 1273 header.incompatible_features = 1274 be64_to_cpu(header.incompatible_features); 1275 header.compatible_features = be64_to_cpu(header.compatible_features); 1276 header.autoclear_features = be64_to_cpu(header.autoclear_features); 1277 header.refcount_order = be32_to_cpu(header.refcount_order); 1278 header.header_length = be32_to_cpu(header.header_length); 1279 1280 if (header.header_length < 104) { 1281 error_setg(errp, "qcow2 header too short"); 1282 ret = -EINVAL; 1283 goto fail; 1284 } 1285 } 1286 1287 if (header.header_length > s->cluster_size) { 1288 error_setg(errp, "qcow2 header exceeds cluster size"); 1289 ret = -EINVAL; 1290 goto fail; 1291 } 1292 1293 if (header.header_length > sizeof(header)) { 1294 s->unknown_header_fields_size = header.header_length - sizeof(header); 1295 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1296 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1297 s->unknown_header_fields_size); 1298 if (ret < 0) { 1299 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1300 "fields"); 1301 goto fail; 1302 } 1303 } 1304 1305 if (header.backing_file_offset > s->cluster_size) { 1306 error_setg(errp, "Invalid backing file offset"); 1307 ret = -EINVAL; 1308 goto fail; 1309 } 1310 1311 if (header.backing_file_offset) { 1312 ext_end = header.backing_file_offset; 1313 } else { 1314 ext_end = 1 << header.cluster_bits; 1315 } 1316 1317 /* Handle feature bits */ 1318 s->incompatible_features = header.incompatible_features; 1319 s->compatible_features = header.compatible_features; 1320 s->autoclear_features = header.autoclear_features; 1321 1322 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1323 void *feature_table = NULL; 1324 qcow2_read_extensions(bs, header.header_length, ext_end, 1325 &feature_table, flags, NULL, NULL); 1326 report_unsupported_feature(errp, feature_table, 1327 s->incompatible_features & 1328 ~QCOW2_INCOMPAT_MASK); 1329 ret = -ENOTSUP; 1330 g_free(feature_table); 1331 goto fail; 1332 } 1333 1334 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1335 /* Corrupt images may not be written to unless they are being repaired 1336 */ 1337 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1338 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1339 "read/write"); 1340 ret = -EACCES; 1341 goto fail; 1342 } 1343 } 1344 1345 /* Check support for various header values */ 1346 if (header.refcount_order > 6) { 1347 error_setg(errp, "Reference count entry width too large; may not " 1348 "exceed 64 bits"); 1349 ret = -EINVAL; 1350 goto fail; 1351 } 1352 s->refcount_order = header.refcount_order; 1353 s->refcount_bits = 1 << s->refcount_order; 1354 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1355 s->refcount_max += s->refcount_max - 1; 1356 1357 s->crypt_method_header = header.crypt_method; 1358 if (s->crypt_method_header) { 1359 if (bdrv_uses_whitelist() && 1360 s->crypt_method_header == QCOW_CRYPT_AES) { 1361 error_setg(errp, 1362 "Use of AES-CBC encrypted qcow2 images is no longer " 1363 "supported in system emulators"); 1364 error_append_hint(errp, 1365 "You can use 'qemu-img convert' to convert your " 1366 "image to an alternative supported format, such " 1367 "as unencrypted qcow2, or raw with the LUKS " 1368 "format instead.\n"); 1369 ret = -ENOSYS; 1370 goto fail; 1371 } 1372 1373 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1374 s->crypt_physical_offset = false; 1375 } else { 1376 /* Assuming LUKS and any future crypt methods we 1377 * add will all use physical offsets, due to the 1378 * fact that the alternative is insecure... */ 1379 s->crypt_physical_offset = true; 1380 } 1381 1382 bs->encrypted = true; 1383 } 1384 1385 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1386 s->l2_size = 1 << s->l2_bits; 1387 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1388 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1389 s->refcount_block_size = 1 << s->refcount_block_bits; 1390 bs->total_sectors = header.size / BDRV_SECTOR_SIZE; 1391 s->csize_shift = (62 - (s->cluster_bits - 8)); 1392 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1393 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1394 1395 s->refcount_table_offset = header.refcount_table_offset; 1396 s->refcount_table_size = 1397 header.refcount_table_clusters << (s->cluster_bits - 3); 1398 1399 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1400 error_setg(errp, "Image does not contain a reference count table"); 1401 ret = -EINVAL; 1402 goto fail; 1403 } 1404 1405 ret = qcow2_validate_table(bs, s->refcount_table_offset, 1406 header.refcount_table_clusters, 1407 s->cluster_size, QCOW_MAX_REFTABLE_SIZE, 1408 "Reference count table", errp); 1409 if (ret < 0) { 1410 goto fail; 1411 } 1412 1413 /* The total size in bytes of the snapshot table is checked in 1414 * qcow2_read_snapshots() because the size of each snapshot is 1415 * variable and we don't know it yet. 1416 * Here we only check the offset and number of snapshots. */ 1417 ret = qcow2_validate_table(bs, header.snapshots_offset, 1418 header.nb_snapshots, 1419 sizeof(QCowSnapshotHeader), 1420 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, 1421 "Snapshot table", errp); 1422 if (ret < 0) { 1423 goto fail; 1424 } 1425 1426 /* read the level 1 table */ 1427 ret = qcow2_validate_table(bs, header.l1_table_offset, 1428 header.l1_size, sizeof(uint64_t), 1429 QCOW_MAX_L1_SIZE, "Active L1 table", errp); 1430 if (ret < 0) { 1431 goto fail; 1432 } 1433 s->l1_size = header.l1_size; 1434 s->l1_table_offset = header.l1_table_offset; 1435 1436 l1_vm_state_index = size_to_l1(s, header.size); 1437 if (l1_vm_state_index > INT_MAX) { 1438 error_setg(errp, "Image is too big"); 1439 ret = -EFBIG; 1440 goto fail; 1441 } 1442 s->l1_vm_state_index = l1_vm_state_index; 1443 1444 /* the L1 table must contain at least enough entries to put 1445 header.size bytes */ 1446 if (s->l1_size < s->l1_vm_state_index) { 1447 error_setg(errp, "L1 table is too small"); 1448 ret = -EINVAL; 1449 goto fail; 1450 } 1451 1452 if (s->l1_size > 0) { 1453 s->l1_table = qemu_try_blockalign(bs->file->bs, 1454 ROUND_UP(s->l1_size * sizeof(uint64_t), 512)); 1455 if (s->l1_table == NULL) { 1456 error_setg(errp, "Could not allocate L1 table"); 1457 ret = -ENOMEM; 1458 goto fail; 1459 } 1460 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1461 s->l1_size * sizeof(uint64_t)); 1462 if (ret < 0) { 1463 error_setg_errno(errp, -ret, "Could not read L1 table"); 1464 goto fail; 1465 } 1466 for(i = 0;i < s->l1_size; i++) { 1467 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 1468 } 1469 } 1470 1471 /* Parse driver-specific options */ 1472 ret = qcow2_update_options(bs, options, flags, errp); 1473 if (ret < 0) { 1474 goto fail; 1475 } 1476 1477 s->flags = flags; 1478 1479 ret = qcow2_refcount_init(bs); 1480 if (ret != 0) { 1481 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1482 goto fail; 1483 } 1484 1485 QLIST_INIT(&s->cluster_allocs); 1486 QTAILQ_INIT(&s->discards); 1487 1488 /* read qcow2 extensions */ 1489 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1490 flags, &update_header, &local_err)) { 1491 error_propagate(errp, local_err); 1492 ret = -EINVAL; 1493 goto fail; 1494 } 1495 1496 /* Open external data file */ 1497 s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file, 1498 true, &local_err); 1499 if (local_err) { 1500 error_propagate(errp, local_err); 1501 ret = -EINVAL; 1502 goto fail; 1503 } 1504 1505 if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { 1506 if (!s->data_file && s->image_data_file) { 1507 s->data_file = bdrv_open_child(s->image_data_file, options, 1508 "data-file", bs, &child_file, 1509 false, errp); 1510 if (!s->data_file) { 1511 ret = -EINVAL; 1512 goto fail; 1513 } 1514 } 1515 if (!s->data_file) { 1516 error_setg(errp, "'data-file' is required for this image"); 1517 ret = -EINVAL; 1518 goto fail; 1519 } 1520 } else { 1521 if (s->data_file) { 1522 error_setg(errp, "'data-file' can only be set for images with an " 1523 "external data file"); 1524 ret = -EINVAL; 1525 goto fail; 1526 } 1527 1528 s->data_file = bs->file; 1529 1530 if (data_file_is_raw(bs)) { 1531 error_setg(errp, "data-file-raw requires a data file"); 1532 ret = -EINVAL; 1533 goto fail; 1534 } 1535 } 1536 1537 /* qcow2_read_extension may have set up the crypto context 1538 * if the crypt method needs a header region, some methods 1539 * don't need header extensions, so must check here 1540 */ 1541 if (s->crypt_method_header && !s->crypto) { 1542 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1543 unsigned int cflags = 0; 1544 if (flags & BDRV_O_NO_IO) { 1545 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1546 } 1547 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1548 NULL, NULL, cflags, 1549 QCOW2_MAX_THREADS, errp); 1550 if (!s->crypto) { 1551 ret = -EINVAL; 1552 goto fail; 1553 } 1554 } else if (!(flags & BDRV_O_NO_IO)) { 1555 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1556 s->crypt_method_header); 1557 ret = -EINVAL; 1558 goto fail; 1559 } 1560 } 1561 1562 /* read the backing file name */ 1563 if (header.backing_file_offset != 0) { 1564 len = header.backing_file_size; 1565 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1566 len >= sizeof(bs->backing_file)) { 1567 error_setg(errp, "Backing file name too long"); 1568 ret = -EINVAL; 1569 goto fail; 1570 } 1571 ret = bdrv_pread(bs->file, header.backing_file_offset, 1572 bs->auto_backing_file, len); 1573 if (ret < 0) { 1574 error_setg_errno(errp, -ret, "Could not read backing file name"); 1575 goto fail; 1576 } 1577 bs->auto_backing_file[len] = '\0'; 1578 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1579 bs->auto_backing_file); 1580 s->image_backing_file = g_strdup(bs->auto_backing_file); 1581 } 1582 1583 /* Internal snapshots */ 1584 s->snapshots_offset = header.snapshots_offset; 1585 s->nb_snapshots = header.nb_snapshots; 1586 1587 ret = qcow2_read_snapshots(bs); 1588 if (ret < 0) { 1589 error_setg_errno(errp, -ret, "Could not read snapshots"); 1590 goto fail; 1591 } 1592 1593 /* Clear unknown autoclear feature bits */ 1594 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1595 update_header = 1596 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1597 if (update_header) { 1598 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1599 } 1600 1601 /* == Handle persistent dirty bitmaps == 1602 * 1603 * We want load dirty bitmaps in three cases: 1604 * 1605 * 1. Normal open of the disk in active mode, not related to invalidation 1606 * after migration. 1607 * 1608 * 2. Invalidation of the target vm after pre-copy phase of migration, if 1609 * bitmaps are _not_ migrating through migration channel, i.e. 1610 * 'dirty-bitmaps' capability is disabled. 1611 * 1612 * 3. Invalidation of source vm after failed or canceled migration. 1613 * This is a very interesting case. There are two possible types of 1614 * bitmaps: 1615 * 1616 * A. Stored on inactivation and removed. They should be loaded from the 1617 * image. 1618 * 1619 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through 1620 * the migration channel (with dirty-bitmaps capability). 1621 * 1622 * On the other hand, there are two possible sub-cases: 1623 * 1624 * 3.1 disk was changed by somebody else while were inactive. In this 1625 * case all in-RAM dirty bitmaps (both persistent and not) are 1626 * definitely invalid. And we don't have any method to determine 1627 * this. 1628 * 1629 * Simple and safe thing is to just drop all the bitmaps of type B on 1630 * inactivation. But in this case we lose bitmaps in valid 4.2 case. 1631 * 1632 * On the other hand, resuming source vm, if disk was already changed 1633 * is a bad thing anyway: not only bitmaps, the whole vm state is 1634 * out of sync with disk. 1635 * 1636 * This means, that user or management tool, who for some reason 1637 * decided to resume source vm, after disk was already changed by 1638 * target vm, should at least drop all dirty bitmaps by hand. 1639 * 1640 * So, we can ignore this case for now, but TODO: "generation" 1641 * extension for qcow2, to determine, that image was changed after 1642 * last inactivation. And if it is changed, we will drop (or at least 1643 * mark as 'invalid' all the bitmaps of type B, both persistent 1644 * and not). 1645 * 1646 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved 1647 * to disk ('dirty-bitmaps' capability disabled), or not saved 1648 * ('dirty-bitmaps' capability enabled), but we don't need to care 1649 * of: let's load bitmaps as always: stored bitmaps will be loaded, 1650 * and not stored has flag IN_USE=1 in the image and will be skipped 1651 * on loading. 1652 * 1653 * One remaining possible case when we don't want load bitmaps: 1654 * 1655 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or 1656 * will be loaded on invalidation, no needs try loading them before) 1657 */ 1658 1659 if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { 1660 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ 1661 bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); 1662 1663 update_header = update_header && !header_updated; 1664 } 1665 if (local_err != NULL) { 1666 error_propagate(errp, local_err); 1667 ret = -EINVAL; 1668 goto fail; 1669 } 1670 1671 if (update_header) { 1672 ret = qcow2_update_header(bs); 1673 if (ret < 0) { 1674 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1675 goto fail; 1676 } 1677 } 1678 1679 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1680 1681 /* Repair image if dirty */ 1682 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1683 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1684 BdrvCheckResult result = {0}; 1685 1686 ret = qcow2_co_check_locked(bs, &result, 1687 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1688 if (ret < 0 || result.check_errors) { 1689 if (ret >= 0) { 1690 ret = -EIO; 1691 } 1692 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1693 goto fail; 1694 } 1695 } 1696 1697 #ifdef DEBUG_ALLOC 1698 { 1699 BdrvCheckResult result = {0}; 1700 qcow2_check_refcounts(bs, &result, 0); 1701 } 1702 #endif 1703 1704 qemu_co_queue_init(&s->thread_task_queue); 1705 1706 return ret; 1707 1708 fail: 1709 g_free(s->image_data_file); 1710 if (has_data_file(bs)) { 1711 bdrv_unref_child(bs, s->data_file); 1712 } 1713 g_free(s->unknown_header_fields); 1714 cleanup_unknown_header_ext(bs); 1715 qcow2_free_snapshots(bs); 1716 qcow2_refcount_close(bs); 1717 qemu_vfree(s->l1_table); 1718 /* else pre-write overlap checks in cache_destroy may crash */ 1719 s->l1_table = NULL; 1720 cache_clean_timer_del(bs); 1721 if (s->l2_table_cache) { 1722 qcow2_cache_destroy(s->l2_table_cache); 1723 } 1724 if (s->refcount_block_cache) { 1725 qcow2_cache_destroy(s->refcount_block_cache); 1726 } 1727 qcrypto_block_free(s->crypto); 1728 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1729 return ret; 1730 } 1731 1732 typedef struct QCow2OpenCo { 1733 BlockDriverState *bs; 1734 QDict *options; 1735 int flags; 1736 Error **errp; 1737 int ret; 1738 } QCow2OpenCo; 1739 1740 static void coroutine_fn qcow2_open_entry(void *opaque) 1741 { 1742 QCow2OpenCo *qoc = opaque; 1743 BDRVQcow2State *s = qoc->bs->opaque; 1744 1745 qemu_co_mutex_lock(&s->lock); 1746 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); 1747 qemu_co_mutex_unlock(&s->lock); 1748 } 1749 1750 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1751 Error **errp) 1752 { 1753 BDRVQcow2State *s = bs->opaque; 1754 QCow2OpenCo qoc = { 1755 .bs = bs, 1756 .options = options, 1757 .flags = flags, 1758 .errp = errp, 1759 .ret = -EINPROGRESS 1760 }; 1761 1762 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1763 false, errp); 1764 if (!bs->file) { 1765 return -EINVAL; 1766 } 1767 1768 /* Initialise locks */ 1769 qemu_co_mutex_init(&s->lock); 1770 1771 if (qemu_in_coroutine()) { 1772 /* From bdrv_co_create. */ 1773 qcow2_open_entry(&qoc); 1774 } else { 1775 assert(qemu_get_current_aio_context() == qemu_get_aio_context()); 1776 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); 1777 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); 1778 } 1779 return qoc.ret; 1780 } 1781 1782 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1783 { 1784 BDRVQcow2State *s = bs->opaque; 1785 1786 if (bs->encrypted) { 1787 /* Encryption works on a sector granularity */ 1788 bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto); 1789 } 1790 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1791 bs->bl.pdiscard_alignment = s->cluster_size; 1792 } 1793 1794 static int qcow2_reopen_prepare(BDRVReopenState *state, 1795 BlockReopenQueue *queue, Error **errp) 1796 { 1797 Qcow2ReopenState *r; 1798 int ret; 1799 1800 r = g_new0(Qcow2ReopenState, 1); 1801 state->opaque = r; 1802 1803 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1804 state->flags, errp); 1805 if (ret < 0) { 1806 goto fail; 1807 } 1808 1809 /* We need to write out any unwritten data if we reopen read-only. */ 1810 if ((state->flags & BDRV_O_RDWR) == 0) { 1811 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1812 if (ret < 0) { 1813 goto fail; 1814 } 1815 1816 ret = bdrv_flush(state->bs); 1817 if (ret < 0) { 1818 goto fail; 1819 } 1820 1821 ret = qcow2_mark_clean(state->bs); 1822 if (ret < 0) { 1823 goto fail; 1824 } 1825 } 1826 1827 return 0; 1828 1829 fail: 1830 qcow2_update_options_abort(state->bs, r); 1831 g_free(r); 1832 return ret; 1833 } 1834 1835 static void qcow2_reopen_commit(BDRVReopenState *state) 1836 { 1837 qcow2_update_options_commit(state->bs, state->opaque); 1838 g_free(state->opaque); 1839 } 1840 1841 static void qcow2_reopen_abort(BDRVReopenState *state) 1842 { 1843 qcow2_update_options_abort(state->bs, state->opaque); 1844 g_free(state->opaque); 1845 } 1846 1847 static void qcow2_join_options(QDict *options, QDict *old_options) 1848 { 1849 bool has_new_overlap_template = 1850 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1851 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1852 bool has_new_total_cache_size = 1853 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1854 bool has_all_cache_options; 1855 1856 /* New overlap template overrides all old overlap options */ 1857 if (has_new_overlap_template) { 1858 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1859 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1860 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1861 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1862 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1863 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1864 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1865 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1866 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1867 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1868 } 1869 1870 /* New total cache size overrides all old options */ 1871 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1872 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1873 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1874 } 1875 1876 qdict_join(options, old_options, false); 1877 1878 /* 1879 * If after merging all cache size options are set, an old total size is 1880 * overwritten. Do keep all options, however, if all three are new. The 1881 * resulting error message is what we want to happen. 1882 */ 1883 has_all_cache_options = 1884 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1885 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1886 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1887 1888 if (has_all_cache_options && !has_new_total_cache_size) { 1889 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1890 } 1891 } 1892 1893 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, 1894 bool want_zero, 1895 int64_t offset, int64_t count, 1896 int64_t *pnum, int64_t *map, 1897 BlockDriverState **file) 1898 { 1899 BDRVQcow2State *s = bs->opaque; 1900 uint64_t cluster_offset; 1901 int index_in_cluster, ret; 1902 unsigned int bytes; 1903 int status = 0; 1904 1905 if (!s->metadata_preallocation_checked) { 1906 ret = qcow2_detect_metadata_preallocation(bs); 1907 s->metadata_preallocation = (ret == 1); 1908 s->metadata_preallocation_checked = true; 1909 } 1910 1911 bytes = MIN(INT_MAX, count); 1912 qemu_co_mutex_lock(&s->lock); 1913 ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); 1914 qemu_co_mutex_unlock(&s->lock); 1915 if (ret < 0) { 1916 return ret; 1917 } 1918 1919 *pnum = bytes; 1920 1921 if ((ret == QCOW2_CLUSTER_NORMAL || ret == QCOW2_CLUSTER_ZERO_ALLOC) && 1922 !s->crypto) { 1923 index_in_cluster = offset & (s->cluster_size - 1); 1924 *map = cluster_offset | index_in_cluster; 1925 *file = s->data_file->bs; 1926 status |= BDRV_BLOCK_OFFSET_VALID; 1927 } 1928 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1929 status |= BDRV_BLOCK_ZERO; 1930 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1931 status |= BDRV_BLOCK_DATA; 1932 } 1933 if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) && 1934 (status & BDRV_BLOCK_OFFSET_VALID)) 1935 { 1936 status |= BDRV_BLOCK_RECURSE; 1937 } 1938 return status; 1939 } 1940 1941 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, 1942 QCowL2Meta **pl2meta, 1943 bool link_l2) 1944 { 1945 int ret = 0; 1946 QCowL2Meta *l2meta = *pl2meta; 1947 1948 while (l2meta != NULL) { 1949 QCowL2Meta *next; 1950 1951 if (link_l2) { 1952 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1953 if (ret) { 1954 goto out; 1955 } 1956 } else { 1957 qcow2_alloc_cluster_abort(bs, l2meta); 1958 } 1959 1960 /* Take the request off the list of running requests */ 1961 if (l2meta->nb_clusters != 0) { 1962 QLIST_REMOVE(l2meta, next_in_flight); 1963 } 1964 1965 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1966 1967 next = l2meta->next; 1968 g_free(l2meta); 1969 l2meta = next; 1970 } 1971 out: 1972 *pl2meta = l2meta; 1973 return ret; 1974 } 1975 1976 static coroutine_fn int 1977 qcow2_co_preadv_encrypted(BlockDriverState *bs, 1978 uint64_t file_cluster_offset, 1979 uint64_t offset, 1980 uint64_t bytes, 1981 QEMUIOVector *qiov, 1982 uint64_t qiov_offset) 1983 { 1984 int ret; 1985 BDRVQcow2State *s = bs->opaque; 1986 uint8_t *buf; 1987 1988 assert(bs->encrypted && s->crypto); 1989 assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1990 1991 /* 1992 * For encrypted images, read everything into a temporary 1993 * contiguous buffer on which the AES functions can work. 1994 * Also, decryption in a separate buffer is better as it 1995 * prevents the guest from learning information about the 1996 * encrypted nature of the virtual disk. 1997 */ 1998 1999 buf = qemu_try_blockalign(s->data_file->bs, bytes); 2000 if (buf == NULL) { 2001 return -ENOMEM; 2002 } 2003 2004 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 2005 ret = bdrv_co_pread(s->data_file, 2006 file_cluster_offset + offset_into_cluster(s, offset), 2007 bytes, buf, 0); 2008 if (ret < 0) { 2009 goto fail; 2010 } 2011 2012 assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)); 2013 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE)); 2014 if (qcow2_co_decrypt(bs, 2015 file_cluster_offset + offset_into_cluster(s, offset), 2016 offset, buf, bytes) < 0) 2017 { 2018 ret = -EIO; 2019 goto fail; 2020 } 2021 qemu_iovec_from_buf(qiov, qiov_offset, buf, bytes); 2022 2023 fail: 2024 qemu_vfree(buf); 2025 2026 return ret; 2027 } 2028 2029 typedef struct Qcow2AioTask { 2030 AioTask task; 2031 2032 BlockDriverState *bs; 2033 QCow2ClusterType cluster_type; /* only for read */ 2034 uint64_t file_cluster_offset; 2035 uint64_t offset; 2036 uint64_t bytes; 2037 QEMUIOVector *qiov; 2038 uint64_t qiov_offset; 2039 QCowL2Meta *l2meta; /* only for write */ 2040 } Qcow2AioTask; 2041 2042 static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task); 2043 static coroutine_fn int qcow2_add_task(BlockDriverState *bs, 2044 AioTaskPool *pool, 2045 AioTaskFunc func, 2046 QCow2ClusterType cluster_type, 2047 uint64_t file_cluster_offset, 2048 uint64_t offset, 2049 uint64_t bytes, 2050 QEMUIOVector *qiov, 2051 size_t qiov_offset, 2052 QCowL2Meta *l2meta) 2053 { 2054 Qcow2AioTask local_task; 2055 Qcow2AioTask *task = pool ? g_new(Qcow2AioTask, 1) : &local_task; 2056 2057 *task = (Qcow2AioTask) { 2058 .task.func = func, 2059 .bs = bs, 2060 .cluster_type = cluster_type, 2061 .qiov = qiov, 2062 .file_cluster_offset = file_cluster_offset, 2063 .offset = offset, 2064 .bytes = bytes, 2065 .qiov_offset = qiov_offset, 2066 .l2meta = l2meta, 2067 }; 2068 2069 trace_qcow2_add_task(qemu_coroutine_self(), bs, pool, 2070 func == qcow2_co_preadv_task_entry ? "read" : "write", 2071 cluster_type, file_cluster_offset, offset, bytes, 2072 qiov, qiov_offset); 2073 2074 if (!pool) { 2075 return func(&task->task); 2076 } 2077 2078 aio_task_pool_start_task(pool, &task->task); 2079 2080 return 0; 2081 } 2082 2083 static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs, 2084 QCow2ClusterType cluster_type, 2085 uint64_t file_cluster_offset, 2086 uint64_t offset, uint64_t bytes, 2087 QEMUIOVector *qiov, 2088 size_t qiov_offset) 2089 { 2090 BDRVQcow2State *s = bs->opaque; 2091 int offset_in_cluster = offset_into_cluster(s, offset); 2092 2093 switch (cluster_type) { 2094 case QCOW2_CLUSTER_ZERO_PLAIN: 2095 case QCOW2_CLUSTER_ZERO_ALLOC: 2096 /* Both zero types are handled in qcow2_co_preadv_part */ 2097 g_assert_not_reached(); 2098 2099 case QCOW2_CLUSTER_UNALLOCATED: 2100 assert(bs->backing); /* otherwise handled in qcow2_co_preadv_part */ 2101 2102 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 2103 return bdrv_co_preadv_part(bs->backing, offset, bytes, 2104 qiov, qiov_offset, 0); 2105 2106 case QCOW2_CLUSTER_COMPRESSED: 2107 return qcow2_co_preadv_compressed(bs, file_cluster_offset, 2108 offset, bytes, qiov, qiov_offset); 2109 2110 case QCOW2_CLUSTER_NORMAL: 2111 if ((file_cluster_offset & 511) != 0) { 2112 return -EIO; 2113 } 2114 2115 if (bs->encrypted) { 2116 return qcow2_co_preadv_encrypted(bs, file_cluster_offset, 2117 offset, bytes, qiov, qiov_offset); 2118 } 2119 2120 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 2121 return bdrv_co_preadv_part(s->data_file, 2122 file_cluster_offset + offset_in_cluster, 2123 bytes, qiov, qiov_offset, 0); 2124 2125 default: 2126 g_assert_not_reached(); 2127 } 2128 2129 g_assert_not_reached(); 2130 } 2131 2132 static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task) 2133 { 2134 Qcow2AioTask *t = container_of(task, Qcow2AioTask, task); 2135 2136 assert(!t->l2meta); 2137 2138 return qcow2_co_preadv_task(t->bs, t->cluster_type, t->file_cluster_offset, 2139 t->offset, t->bytes, t->qiov, t->qiov_offset); 2140 } 2141 2142 static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs, 2143 uint64_t offset, uint64_t bytes, 2144 QEMUIOVector *qiov, 2145 size_t qiov_offset, int flags) 2146 { 2147 BDRVQcow2State *s = bs->opaque; 2148 int ret = 0; 2149 unsigned int cur_bytes; /* number of bytes in current iteration */ 2150 uint64_t cluster_offset = 0; 2151 AioTaskPool *aio = NULL; 2152 2153 while (bytes != 0 && aio_task_pool_status(aio) == 0) { 2154 /* prepare next request */ 2155 cur_bytes = MIN(bytes, INT_MAX); 2156 if (s->crypto) { 2157 cur_bytes = MIN(cur_bytes, 2158 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2159 } 2160 2161 qemu_co_mutex_lock(&s->lock); 2162 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 2163 qemu_co_mutex_unlock(&s->lock); 2164 if (ret < 0) { 2165 goto out; 2166 } 2167 2168 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || 2169 ret == QCOW2_CLUSTER_ZERO_ALLOC || 2170 (ret == QCOW2_CLUSTER_UNALLOCATED && !bs->backing)) 2171 { 2172 qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes); 2173 } else { 2174 if (!aio && cur_bytes != bytes) { 2175 aio = aio_task_pool_new(QCOW2_MAX_WORKERS); 2176 } 2177 ret = qcow2_add_task(bs, aio, qcow2_co_preadv_task_entry, ret, 2178 cluster_offset, offset, cur_bytes, 2179 qiov, qiov_offset, NULL); 2180 if (ret < 0) { 2181 goto out; 2182 } 2183 } 2184 2185 bytes -= cur_bytes; 2186 offset += cur_bytes; 2187 qiov_offset += cur_bytes; 2188 } 2189 2190 out: 2191 if (aio) { 2192 aio_task_pool_wait_all(aio); 2193 if (ret == 0) { 2194 ret = aio_task_pool_status(aio); 2195 } 2196 g_free(aio); 2197 } 2198 2199 return ret; 2200 } 2201 2202 /* Check if it's possible to merge a write request with the writing of 2203 * the data from the COW regions */ 2204 static bool merge_cow(uint64_t offset, unsigned bytes, 2205 QEMUIOVector *qiov, size_t qiov_offset, 2206 QCowL2Meta *l2meta) 2207 { 2208 QCowL2Meta *m; 2209 2210 for (m = l2meta; m != NULL; m = m->next) { 2211 /* If both COW regions are empty then there's nothing to merge */ 2212 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 2213 continue; 2214 } 2215 2216 /* If COW regions are handled already, skip this too */ 2217 if (m->skip_cow) { 2218 continue; 2219 } 2220 2221 /* The data (middle) region must be immediately after the 2222 * start region */ 2223 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 2224 continue; 2225 } 2226 2227 /* The end region must be immediately after the data (middle) 2228 * region */ 2229 if (m->offset + m->cow_end.offset != offset + bytes) { 2230 continue; 2231 } 2232 2233 /* Make sure that adding both COW regions to the QEMUIOVector 2234 * does not exceed IOV_MAX */ 2235 if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) { 2236 continue; 2237 } 2238 2239 m->data_qiov = qiov; 2240 m->data_qiov_offset = qiov_offset; 2241 return true; 2242 } 2243 2244 return false; 2245 } 2246 2247 static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes) 2248 { 2249 int64_t nr; 2250 return !bytes || 2251 (!bdrv_is_allocated_above(bs, NULL, false, offset, bytes, &nr) && 2252 nr == bytes); 2253 } 2254 2255 static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m) 2256 { 2257 /* 2258 * This check is designed for optimization shortcut so it must be 2259 * efficient. 2260 * Instead of is_zero(), use is_unallocated() as it is faster (but not 2261 * as accurate and can result in false negatives). 2262 */ 2263 return is_unallocated(bs, m->offset + m->cow_start.offset, 2264 m->cow_start.nb_bytes) && 2265 is_unallocated(bs, m->offset + m->cow_end.offset, 2266 m->cow_end.nb_bytes); 2267 } 2268 2269 static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) 2270 { 2271 BDRVQcow2State *s = bs->opaque; 2272 QCowL2Meta *m; 2273 2274 if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) { 2275 return 0; 2276 } 2277 2278 if (bs->encrypted) { 2279 return 0; 2280 } 2281 2282 for (m = l2meta; m != NULL; m = m->next) { 2283 int ret; 2284 2285 if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) { 2286 continue; 2287 } 2288 2289 if (!is_zero_cow(bs, m)) { 2290 continue; 2291 } 2292 2293 /* 2294 * instead of writing zero COW buffers, 2295 * efficiently zero out the whole clusters 2296 */ 2297 2298 ret = qcow2_pre_write_overlap_check(bs, 0, m->alloc_offset, 2299 m->nb_clusters * s->cluster_size, 2300 true); 2301 if (ret < 0) { 2302 return ret; 2303 } 2304 2305 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE); 2306 ret = bdrv_co_pwrite_zeroes(s->data_file, m->alloc_offset, 2307 m->nb_clusters * s->cluster_size, 2308 BDRV_REQ_NO_FALLBACK); 2309 if (ret < 0) { 2310 if (ret != -ENOTSUP && ret != -EAGAIN) { 2311 return ret; 2312 } 2313 continue; 2314 } 2315 2316 trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters); 2317 m->skip_cow = true; 2318 } 2319 return 0; 2320 } 2321 2322 /* 2323 * qcow2_co_pwritev_task 2324 * Called with s->lock unlocked 2325 * l2meta - if not NULL, qcow2_co_pwritev_task() will consume it. Caller must 2326 * not use it somehow after qcow2_co_pwritev_task() call 2327 */ 2328 static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs, 2329 uint64_t file_cluster_offset, 2330 uint64_t offset, uint64_t bytes, 2331 QEMUIOVector *qiov, 2332 uint64_t qiov_offset, 2333 QCowL2Meta *l2meta) 2334 { 2335 int ret; 2336 BDRVQcow2State *s = bs->opaque; 2337 void *crypt_buf = NULL; 2338 int offset_in_cluster = offset_into_cluster(s, offset); 2339 QEMUIOVector encrypted_qiov; 2340 2341 if (bs->encrypted) { 2342 assert(s->crypto); 2343 assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2344 crypt_buf = qemu_try_blockalign(bs->file->bs, bytes); 2345 if (crypt_buf == NULL) { 2346 ret = -ENOMEM; 2347 goto out_unlocked; 2348 } 2349 qemu_iovec_to_buf(qiov, qiov_offset, crypt_buf, bytes); 2350 2351 if (qcow2_co_encrypt(bs, file_cluster_offset + offset_in_cluster, 2352 offset, crypt_buf, bytes) < 0) 2353 { 2354 ret = -EIO; 2355 goto out_unlocked; 2356 } 2357 2358 qemu_iovec_init_buf(&encrypted_qiov, crypt_buf, bytes); 2359 qiov = &encrypted_qiov; 2360 qiov_offset = 0; 2361 } 2362 2363 /* Try to efficiently initialize the physical space with zeroes */ 2364 ret = handle_alloc_space(bs, l2meta); 2365 if (ret < 0) { 2366 goto out_unlocked; 2367 } 2368 2369 /* 2370 * If we need to do COW, check if it's possible to merge the 2371 * writing of the guest data together with that of the COW regions. 2372 * If it's not possible (or not necessary) then write the 2373 * guest data now. 2374 */ 2375 if (!merge_cow(offset, bytes, qiov, qiov_offset, l2meta)) { 2376 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 2377 trace_qcow2_writev_data(qemu_coroutine_self(), 2378 file_cluster_offset + offset_in_cluster); 2379 ret = bdrv_co_pwritev_part(s->data_file, 2380 file_cluster_offset + offset_in_cluster, 2381 bytes, qiov, qiov_offset, 0); 2382 if (ret < 0) { 2383 goto out_unlocked; 2384 } 2385 } 2386 2387 qemu_co_mutex_lock(&s->lock); 2388 2389 ret = qcow2_handle_l2meta(bs, &l2meta, true); 2390 goto out_locked; 2391 2392 out_unlocked: 2393 qemu_co_mutex_lock(&s->lock); 2394 2395 out_locked: 2396 qcow2_handle_l2meta(bs, &l2meta, false); 2397 qemu_co_mutex_unlock(&s->lock); 2398 2399 qemu_vfree(crypt_buf); 2400 2401 return ret; 2402 } 2403 2404 static coroutine_fn int qcow2_co_pwritev_task_entry(AioTask *task) 2405 { 2406 Qcow2AioTask *t = container_of(task, Qcow2AioTask, task); 2407 2408 assert(!t->cluster_type); 2409 2410 return qcow2_co_pwritev_task(t->bs, t->file_cluster_offset, 2411 t->offset, t->bytes, t->qiov, t->qiov_offset, 2412 t->l2meta); 2413 } 2414 2415 static coroutine_fn int qcow2_co_pwritev_part( 2416 BlockDriverState *bs, uint64_t offset, uint64_t bytes, 2417 QEMUIOVector *qiov, size_t qiov_offset, int flags) 2418 { 2419 BDRVQcow2State *s = bs->opaque; 2420 int offset_in_cluster; 2421 int ret; 2422 unsigned int cur_bytes; /* number of sectors in current iteration */ 2423 uint64_t cluster_offset; 2424 QCowL2Meta *l2meta = NULL; 2425 AioTaskPool *aio = NULL; 2426 2427 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 2428 2429 while (bytes != 0 && aio_task_pool_status(aio) == 0) { 2430 2431 l2meta = NULL; 2432 2433 trace_qcow2_writev_start_part(qemu_coroutine_self()); 2434 offset_in_cluster = offset_into_cluster(s, offset); 2435 cur_bytes = MIN(bytes, INT_MAX); 2436 if (bs->encrypted) { 2437 cur_bytes = MIN(cur_bytes, 2438 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 2439 - offset_in_cluster); 2440 } 2441 2442 qemu_co_mutex_lock(&s->lock); 2443 2444 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2445 &cluster_offset, &l2meta); 2446 if (ret < 0) { 2447 goto out_locked; 2448 } 2449 2450 assert((cluster_offset & 511) == 0); 2451 2452 ret = qcow2_pre_write_overlap_check(bs, 0, 2453 cluster_offset + offset_in_cluster, 2454 cur_bytes, true); 2455 if (ret < 0) { 2456 goto out_locked; 2457 } 2458 2459 qemu_co_mutex_unlock(&s->lock); 2460 2461 if (!aio && cur_bytes != bytes) { 2462 aio = aio_task_pool_new(QCOW2_MAX_WORKERS); 2463 } 2464 ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_task_entry, 0, 2465 cluster_offset, offset, cur_bytes, 2466 qiov, qiov_offset, l2meta); 2467 l2meta = NULL; /* l2meta is consumed by qcow2_co_pwritev_task() */ 2468 if (ret < 0) { 2469 goto fail_nometa; 2470 } 2471 2472 bytes -= cur_bytes; 2473 offset += cur_bytes; 2474 qiov_offset += cur_bytes; 2475 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2476 } 2477 ret = 0; 2478 2479 qemu_co_mutex_lock(&s->lock); 2480 2481 out_locked: 2482 qcow2_handle_l2meta(bs, &l2meta, false); 2483 2484 qemu_co_mutex_unlock(&s->lock); 2485 2486 fail_nometa: 2487 if (aio) { 2488 aio_task_pool_wait_all(aio); 2489 if (ret == 0) { 2490 ret = aio_task_pool_status(aio); 2491 } 2492 g_free(aio); 2493 } 2494 2495 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2496 2497 return ret; 2498 } 2499 2500 static int qcow2_inactivate(BlockDriverState *bs) 2501 { 2502 BDRVQcow2State *s = bs->opaque; 2503 int ret, result = 0; 2504 Error *local_err = NULL; 2505 2506 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2507 if (local_err != NULL) { 2508 result = -EINVAL; 2509 error_reportf_err(local_err, "Lost persistent bitmaps during " 2510 "inactivation of node '%s': ", 2511 bdrv_get_device_or_node_name(bs)); 2512 } 2513 2514 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2515 if (ret) { 2516 result = ret; 2517 error_report("Failed to flush the L2 table cache: %s", 2518 strerror(-ret)); 2519 } 2520 2521 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2522 if (ret) { 2523 result = ret; 2524 error_report("Failed to flush the refcount block cache: %s", 2525 strerror(-ret)); 2526 } 2527 2528 if (result == 0) { 2529 qcow2_mark_clean(bs); 2530 } 2531 2532 return result; 2533 } 2534 2535 static void qcow2_close(BlockDriverState *bs) 2536 { 2537 BDRVQcow2State *s = bs->opaque; 2538 qemu_vfree(s->l1_table); 2539 /* else pre-write overlap checks in cache_destroy may crash */ 2540 s->l1_table = NULL; 2541 2542 if (!(s->flags & BDRV_O_INACTIVE)) { 2543 qcow2_inactivate(bs); 2544 } 2545 2546 cache_clean_timer_del(bs); 2547 qcow2_cache_destroy(s->l2_table_cache); 2548 qcow2_cache_destroy(s->refcount_block_cache); 2549 2550 qcrypto_block_free(s->crypto); 2551 s->crypto = NULL; 2552 2553 g_free(s->unknown_header_fields); 2554 cleanup_unknown_header_ext(bs); 2555 2556 g_free(s->image_data_file); 2557 g_free(s->image_backing_file); 2558 g_free(s->image_backing_format); 2559 2560 if (has_data_file(bs)) { 2561 bdrv_unref_child(bs, s->data_file); 2562 } 2563 2564 qcow2_refcount_close(bs); 2565 qcow2_free_snapshots(bs); 2566 } 2567 2568 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, 2569 Error **errp) 2570 { 2571 BDRVQcow2State *s = bs->opaque; 2572 int flags = s->flags; 2573 QCryptoBlock *crypto = NULL; 2574 QDict *options; 2575 Error *local_err = NULL; 2576 int ret; 2577 2578 /* 2579 * Backing files are read-only which makes all of their metadata immutable, 2580 * that means we don't have to worry about reopening them here. 2581 */ 2582 2583 crypto = s->crypto; 2584 s->crypto = NULL; 2585 2586 qcow2_close(bs); 2587 2588 memset(s, 0, sizeof(BDRVQcow2State)); 2589 options = qdict_clone_shallow(bs->options); 2590 2591 flags &= ~BDRV_O_INACTIVE; 2592 qemu_co_mutex_lock(&s->lock); 2593 ret = qcow2_do_open(bs, options, flags, &local_err); 2594 qemu_co_mutex_unlock(&s->lock); 2595 qobject_unref(options); 2596 if (local_err) { 2597 error_propagate_prepend(errp, local_err, 2598 "Could not reopen qcow2 layer: "); 2599 bs->drv = NULL; 2600 return; 2601 } else if (ret < 0) { 2602 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2603 bs->drv = NULL; 2604 return; 2605 } 2606 2607 s->crypto = crypto; 2608 } 2609 2610 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2611 size_t len, size_t buflen) 2612 { 2613 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2614 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2615 2616 if (buflen < ext_len) { 2617 return -ENOSPC; 2618 } 2619 2620 *ext_backing_fmt = (QCowExtension) { 2621 .magic = cpu_to_be32(magic), 2622 .len = cpu_to_be32(len), 2623 }; 2624 2625 if (len) { 2626 memcpy(buf + sizeof(QCowExtension), s, len); 2627 } 2628 2629 return ext_len; 2630 } 2631 2632 /* 2633 * Updates the qcow2 header, including the variable length parts of it, i.e. 2634 * the backing file name and all extensions. qcow2 was not designed to allow 2635 * such changes, so if we run out of space (we can only use the first cluster) 2636 * this function may fail. 2637 * 2638 * Returns 0 on success, -errno in error cases. 2639 */ 2640 int qcow2_update_header(BlockDriverState *bs) 2641 { 2642 BDRVQcow2State *s = bs->opaque; 2643 QCowHeader *header; 2644 char *buf; 2645 size_t buflen = s->cluster_size; 2646 int ret; 2647 uint64_t total_size; 2648 uint32_t refcount_table_clusters; 2649 size_t header_length; 2650 Qcow2UnknownHeaderExtension *uext; 2651 2652 buf = qemu_blockalign(bs, buflen); 2653 2654 /* Header structure */ 2655 header = (QCowHeader*) buf; 2656 2657 if (buflen < sizeof(*header)) { 2658 ret = -ENOSPC; 2659 goto fail; 2660 } 2661 2662 header_length = sizeof(*header) + s->unknown_header_fields_size; 2663 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2664 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2665 2666 *header = (QCowHeader) { 2667 /* Version 2 fields */ 2668 .magic = cpu_to_be32(QCOW_MAGIC), 2669 .version = cpu_to_be32(s->qcow_version), 2670 .backing_file_offset = 0, 2671 .backing_file_size = 0, 2672 .cluster_bits = cpu_to_be32(s->cluster_bits), 2673 .size = cpu_to_be64(total_size), 2674 .crypt_method = cpu_to_be32(s->crypt_method_header), 2675 .l1_size = cpu_to_be32(s->l1_size), 2676 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2677 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2678 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2679 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2680 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2681 2682 /* Version 3 fields */ 2683 .incompatible_features = cpu_to_be64(s->incompatible_features), 2684 .compatible_features = cpu_to_be64(s->compatible_features), 2685 .autoclear_features = cpu_to_be64(s->autoclear_features), 2686 .refcount_order = cpu_to_be32(s->refcount_order), 2687 .header_length = cpu_to_be32(header_length), 2688 }; 2689 2690 /* For older versions, write a shorter header */ 2691 switch (s->qcow_version) { 2692 case 2: 2693 ret = offsetof(QCowHeader, incompatible_features); 2694 break; 2695 case 3: 2696 ret = sizeof(*header); 2697 break; 2698 default: 2699 ret = -EINVAL; 2700 goto fail; 2701 } 2702 2703 buf += ret; 2704 buflen -= ret; 2705 memset(buf, 0, buflen); 2706 2707 /* Preserve any unknown field in the header */ 2708 if (s->unknown_header_fields_size) { 2709 if (buflen < s->unknown_header_fields_size) { 2710 ret = -ENOSPC; 2711 goto fail; 2712 } 2713 2714 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2715 buf += s->unknown_header_fields_size; 2716 buflen -= s->unknown_header_fields_size; 2717 } 2718 2719 /* Backing file format header extension */ 2720 if (s->image_backing_format) { 2721 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2722 s->image_backing_format, 2723 strlen(s->image_backing_format), 2724 buflen); 2725 if (ret < 0) { 2726 goto fail; 2727 } 2728 2729 buf += ret; 2730 buflen -= ret; 2731 } 2732 2733 /* External data file header extension */ 2734 if (has_data_file(bs) && s->image_data_file) { 2735 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE, 2736 s->image_data_file, strlen(s->image_data_file), 2737 buflen); 2738 if (ret < 0) { 2739 goto fail; 2740 } 2741 2742 buf += ret; 2743 buflen -= ret; 2744 } 2745 2746 /* Full disk encryption header pointer extension */ 2747 if (s->crypto_header.offset != 0) { 2748 s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset); 2749 s->crypto_header.length = cpu_to_be64(s->crypto_header.length); 2750 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2751 &s->crypto_header, sizeof(s->crypto_header), 2752 buflen); 2753 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 2754 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 2755 if (ret < 0) { 2756 goto fail; 2757 } 2758 buf += ret; 2759 buflen -= ret; 2760 } 2761 2762 /* Feature table */ 2763 if (s->qcow_version >= 3) { 2764 Qcow2Feature features[] = { 2765 { 2766 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2767 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2768 .name = "dirty bit", 2769 }, 2770 { 2771 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2772 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2773 .name = "corrupt bit", 2774 }, 2775 { 2776 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2777 .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR, 2778 .name = "external data file", 2779 }, 2780 { 2781 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2782 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2783 .name = "lazy refcounts", 2784 }, 2785 }; 2786 2787 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2788 features, sizeof(features), buflen); 2789 if (ret < 0) { 2790 goto fail; 2791 } 2792 buf += ret; 2793 buflen -= ret; 2794 } 2795 2796 /* Bitmap extension */ 2797 if (s->nb_bitmaps > 0) { 2798 Qcow2BitmapHeaderExt bitmaps_header = { 2799 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2800 .bitmap_directory_size = 2801 cpu_to_be64(s->bitmap_directory_size), 2802 .bitmap_directory_offset = 2803 cpu_to_be64(s->bitmap_directory_offset) 2804 }; 2805 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2806 &bitmaps_header, sizeof(bitmaps_header), 2807 buflen); 2808 if (ret < 0) { 2809 goto fail; 2810 } 2811 buf += ret; 2812 buflen -= ret; 2813 } 2814 2815 /* Keep unknown header extensions */ 2816 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2817 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2818 if (ret < 0) { 2819 goto fail; 2820 } 2821 2822 buf += ret; 2823 buflen -= ret; 2824 } 2825 2826 /* End of header extensions */ 2827 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2828 if (ret < 0) { 2829 goto fail; 2830 } 2831 2832 buf += ret; 2833 buflen -= ret; 2834 2835 /* Backing file name */ 2836 if (s->image_backing_file) { 2837 size_t backing_file_len = strlen(s->image_backing_file); 2838 2839 if (buflen < backing_file_len) { 2840 ret = -ENOSPC; 2841 goto fail; 2842 } 2843 2844 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2845 strncpy(buf, s->image_backing_file, buflen); 2846 2847 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2848 header->backing_file_size = cpu_to_be32(backing_file_len); 2849 } 2850 2851 /* Write the new header */ 2852 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2853 if (ret < 0) { 2854 goto fail; 2855 } 2856 2857 ret = 0; 2858 fail: 2859 qemu_vfree(header); 2860 return ret; 2861 } 2862 2863 static int qcow2_change_backing_file(BlockDriverState *bs, 2864 const char *backing_file, const char *backing_fmt) 2865 { 2866 BDRVQcow2State *s = bs->opaque; 2867 2868 /* Adding a backing file means that the external data file alone won't be 2869 * enough to make sense of the content */ 2870 if (backing_file && data_file_is_raw(bs)) { 2871 return -EINVAL; 2872 } 2873 2874 if (backing_file && strlen(backing_file) > 1023) { 2875 return -EINVAL; 2876 } 2877 2878 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), 2879 backing_file ?: ""); 2880 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2881 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2882 2883 g_free(s->image_backing_file); 2884 g_free(s->image_backing_format); 2885 2886 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2887 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2888 2889 return qcow2_update_header(bs); 2890 } 2891 2892 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2893 { 2894 if (g_str_equal(encryptfmt, "luks")) { 2895 return QCOW_CRYPT_LUKS; 2896 } else if (g_str_equal(encryptfmt, "aes")) { 2897 return QCOW_CRYPT_AES; 2898 } else { 2899 return -EINVAL; 2900 } 2901 } 2902 2903 static int qcow2_set_up_encryption(BlockDriverState *bs, 2904 QCryptoBlockCreateOptions *cryptoopts, 2905 Error **errp) 2906 { 2907 BDRVQcow2State *s = bs->opaque; 2908 QCryptoBlock *crypto = NULL; 2909 int fmt, ret; 2910 2911 switch (cryptoopts->format) { 2912 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 2913 fmt = QCOW_CRYPT_LUKS; 2914 break; 2915 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 2916 fmt = QCOW_CRYPT_AES; 2917 break; 2918 default: 2919 error_setg(errp, "Crypto format not supported in qcow2"); 2920 return -EINVAL; 2921 } 2922 2923 s->crypt_method_header = fmt; 2924 2925 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2926 qcow2_crypto_hdr_init_func, 2927 qcow2_crypto_hdr_write_func, 2928 bs, errp); 2929 if (!crypto) { 2930 return -EINVAL; 2931 } 2932 2933 ret = qcow2_update_header(bs); 2934 if (ret < 0) { 2935 error_setg_errno(errp, -ret, "Could not write encryption header"); 2936 goto out; 2937 } 2938 2939 ret = 0; 2940 out: 2941 qcrypto_block_free(crypto); 2942 return ret; 2943 } 2944 2945 /** 2946 * Preallocates metadata structures for data clusters between @offset (in the 2947 * guest disk) and @new_length (which is thus generally the new guest disk 2948 * size). 2949 * 2950 * Returns: 0 on success, -errno on failure. 2951 */ 2952 static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, 2953 uint64_t new_length, PreallocMode mode, 2954 Error **errp) 2955 { 2956 BDRVQcow2State *s = bs->opaque; 2957 uint64_t bytes; 2958 uint64_t host_offset = 0; 2959 int64_t file_length; 2960 unsigned int cur_bytes; 2961 int ret; 2962 QCowL2Meta *meta; 2963 2964 assert(offset <= new_length); 2965 bytes = new_length - offset; 2966 2967 while (bytes) { 2968 cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size)); 2969 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2970 &host_offset, &meta); 2971 if (ret < 0) { 2972 error_setg_errno(errp, -ret, "Allocating clusters failed"); 2973 return ret; 2974 } 2975 2976 while (meta) { 2977 QCowL2Meta *next = meta->next; 2978 2979 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2980 if (ret < 0) { 2981 error_setg_errno(errp, -ret, "Mapping clusters failed"); 2982 qcow2_free_any_clusters(bs, meta->alloc_offset, 2983 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2984 return ret; 2985 } 2986 2987 /* There are no dependent requests, but we need to remove our 2988 * request from the list of in-flight requests */ 2989 QLIST_REMOVE(meta, next_in_flight); 2990 2991 g_free(meta); 2992 meta = next; 2993 } 2994 2995 /* TODO Preallocate data if requested */ 2996 2997 bytes -= cur_bytes; 2998 offset += cur_bytes; 2999 } 3000 3001 /* 3002 * It is expected that the image file is large enough to actually contain 3003 * all of the allocated clusters (otherwise we get failing reads after 3004 * EOF). Extend the image to the last allocated sector. 3005 */ 3006 file_length = bdrv_getlength(s->data_file->bs); 3007 if (file_length < 0) { 3008 error_setg_errno(errp, -file_length, "Could not get file size"); 3009 return file_length; 3010 } 3011 3012 if (host_offset + cur_bytes > file_length) { 3013 if (mode == PREALLOC_MODE_METADATA) { 3014 mode = PREALLOC_MODE_OFF; 3015 } 3016 ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, mode, 3017 errp); 3018 if (ret < 0) { 3019 return ret; 3020 } 3021 } 3022 3023 return 0; 3024 } 3025 3026 /* qcow2_refcount_metadata_size: 3027 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 3028 * @cluster_size: size of a cluster, in bytes 3029 * @refcount_order: refcount bits power-of-2 exponent 3030 * @generous_increase: allow for the refcount table to be 1.5x as large as it 3031 * needs to be 3032 * 3033 * Returns: Number of bytes required for refcount blocks and table metadata. 3034 */ 3035 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 3036 int refcount_order, bool generous_increase, 3037 uint64_t *refblock_count) 3038 { 3039 /* 3040 * Every host cluster is reference-counted, including metadata (even 3041 * refcount metadata is recursively included). 3042 * 3043 * An accurate formula for the size of refcount metadata size is difficult 3044 * to derive. An easier method of calculation is finding the fixed point 3045 * where no further refcount blocks or table clusters are required to 3046 * reference count every cluster. 3047 */ 3048 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 3049 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 3050 int64_t table = 0; /* number of refcount table clusters */ 3051 int64_t blocks = 0; /* number of refcount block clusters */ 3052 int64_t last; 3053 int64_t n = 0; 3054 3055 do { 3056 last = n; 3057 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 3058 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 3059 n = clusters + blocks + table; 3060 3061 if (n == last && generous_increase) { 3062 clusters += DIV_ROUND_UP(table, 2); 3063 n = 0; /* force another loop */ 3064 generous_increase = false; 3065 } 3066 } while (n != last); 3067 3068 if (refblock_count) { 3069 *refblock_count = blocks; 3070 } 3071 3072 return (blocks + table) * cluster_size; 3073 } 3074 3075 /** 3076 * qcow2_calc_prealloc_size: 3077 * @total_size: virtual disk size in bytes 3078 * @cluster_size: cluster size in bytes 3079 * @refcount_order: refcount bits power-of-2 exponent 3080 * 3081 * Returns: Total number of bytes required for the fully allocated image 3082 * (including metadata). 3083 */ 3084 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 3085 size_t cluster_size, 3086 int refcount_order) 3087 { 3088 int64_t meta_size = 0; 3089 uint64_t nl1e, nl2e; 3090 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); 3091 3092 /* header: 1 cluster */ 3093 meta_size += cluster_size; 3094 3095 /* total size of L2 tables */ 3096 nl2e = aligned_total_size / cluster_size; 3097 nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t)); 3098 meta_size += nl2e * sizeof(uint64_t); 3099 3100 /* total size of L1 tables */ 3101 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 3102 nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t)); 3103 meta_size += nl1e * sizeof(uint64_t); 3104 3105 /* total size of refcount table and blocks */ 3106 meta_size += qcow2_refcount_metadata_size( 3107 (meta_size + aligned_total_size) / cluster_size, 3108 cluster_size, refcount_order, false, NULL); 3109 3110 return meta_size + aligned_total_size; 3111 } 3112 3113 static bool validate_cluster_size(size_t cluster_size, Error **errp) 3114 { 3115 int cluster_bits = ctz32(cluster_size); 3116 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 3117 (1 << cluster_bits) != cluster_size) 3118 { 3119 error_setg(errp, "Cluster size must be a power of two between %d and " 3120 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 3121 return false; 3122 } 3123 return true; 3124 } 3125 3126 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 3127 { 3128 size_t cluster_size; 3129 3130 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 3131 DEFAULT_CLUSTER_SIZE); 3132 if (!validate_cluster_size(cluster_size, errp)) { 3133 return 0; 3134 } 3135 return cluster_size; 3136 } 3137 3138 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 3139 { 3140 char *buf; 3141 int ret; 3142 3143 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 3144 if (!buf) { 3145 ret = 3; /* default */ 3146 } else if (!strcmp(buf, "0.10")) { 3147 ret = 2; 3148 } else if (!strcmp(buf, "1.1")) { 3149 ret = 3; 3150 } else { 3151 error_setg(errp, "Invalid compatibility level: '%s'", buf); 3152 ret = -EINVAL; 3153 } 3154 g_free(buf); 3155 return ret; 3156 } 3157 3158 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 3159 Error **errp) 3160 { 3161 uint64_t refcount_bits; 3162 3163 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 3164 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 3165 error_setg(errp, "Refcount width must be a power of two and may not " 3166 "exceed 64 bits"); 3167 return 0; 3168 } 3169 3170 if (version < 3 && refcount_bits != 16) { 3171 error_setg(errp, "Different refcount widths than 16 bits require " 3172 "compatibility level 1.1 or above (use compat=1.1 or " 3173 "greater)"); 3174 return 0; 3175 } 3176 3177 return refcount_bits; 3178 } 3179 3180 static int coroutine_fn 3181 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 3182 { 3183 BlockdevCreateOptionsQcow2 *qcow2_opts; 3184 QDict *options; 3185 3186 /* 3187 * Open the image file and write a minimal qcow2 header. 3188 * 3189 * We keep things simple and start with a zero-sized image. We also 3190 * do without refcount blocks or a L1 table for now. We'll fix the 3191 * inconsistency later. 3192 * 3193 * We do need a refcount table because growing the refcount table means 3194 * allocating two new refcount blocks - the seconds of which would be at 3195 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 3196 * size for any qcow2 image. 3197 */ 3198 BlockBackend *blk = NULL; 3199 BlockDriverState *bs = NULL; 3200 BlockDriverState *data_bs = NULL; 3201 QCowHeader *header; 3202 size_t cluster_size; 3203 int version; 3204 int refcount_order; 3205 uint64_t* refcount_table; 3206 Error *local_err = NULL; 3207 int ret; 3208 3209 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); 3210 qcow2_opts = &create_options->u.qcow2; 3211 3212 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); 3213 if (bs == NULL) { 3214 return -EIO; 3215 } 3216 3217 /* Validate options and set default values */ 3218 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { 3219 error_setg(errp, "Image size must be a multiple of 512 bytes"); 3220 ret = -EINVAL; 3221 goto out; 3222 } 3223 3224 if (qcow2_opts->has_version) { 3225 switch (qcow2_opts->version) { 3226 case BLOCKDEV_QCOW2_VERSION_V2: 3227 version = 2; 3228 break; 3229 case BLOCKDEV_QCOW2_VERSION_V3: 3230 version = 3; 3231 break; 3232 default: 3233 g_assert_not_reached(); 3234 } 3235 } else { 3236 version = 3; 3237 } 3238 3239 if (qcow2_opts->has_cluster_size) { 3240 cluster_size = qcow2_opts->cluster_size; 3241 } else { 3242 cluster_size = DEFAULT_CLUSTER_SIZE; 3243 } 3244 3245 if (!validate_cluster_size(cluster_size, errp)) { 3246 ret = -EINVAL; 3247 goto out; 3248 } 3249 3250 if (!qcow2_opts->has_preallocation) { 3251 qcow2_opts->preallocation = PREALLOC_MODE_OFF; 3252 } 3253 if (qcow2_opts->has_backing_file && 3254 qcow2_opts->preallocation != PREALLOC_MODE_OFF) 3255 { 3256 error_setg(errp, "Backing file and preallocation cannot be used at " 3257 "the same time"); 3258 ret = -EINVAL; 3259 goto out; 3260 } 3261 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { 3262 error_setg(errp, "Backing format cannot be used without backing file"); 3263 ret = -EINVAL; 3264 goto out; 3265 } 3266 3267 if (!qcow2_opts->has_lazy_refcounts) { 3268 qcow2_opts->lazy_refcounts = false; 3269 } 3270 if (version < 3 && qcow2_opts->lazy_refcounts) { 3271 error_setg(errp, "Lazy refcounts only supported with compatibility " 3272 "level 1.1 and above (use version=v3 or greater)"); 3273 ret = -EINVAL; 3274 goto out; 3275 } 3276 3277 if (!qcow2_opts->has_refcount_bits) { 3278 qcow2_opts->refcount_bits = 16; 3279 } 3280 if (qcow2_opts->refcount_bits > 64 || 3281 !is_power_of_2(qcow2_opts->refcount_bits)) 3282 { 3283 error_setg(errp, "Refcount width must be a power of two and may not " 3284 "exceed 64 bits"); 3285 ret = -EINVAL; 3286 goto out; 3287 } 3288 if (version < 3 && qcow2_opts->refcount_bits != 16) { 3289 error_setg(errp, "Different refcount widths than 16 bits require " 3290 "compatibility level 1.1 or above (use version=v3 or " 3291 "greater)"); 3292 ret = -EINVAL; 3293 goto out; 3294 } 3295 refcount_order = ctz32(qcow2_opts->refcount_bits); 3296 3297 if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) { 3298 error_setg(errp, "data-file-raw requires data-file"); 3299 ret = -EINVAL; 3300 goto out; 3301 } 3302 if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) { 3303 error_setg(errp, "Backing file and data-file-raw cannot be used at " 3304 "the same time"); 3305 ret = -EINVAL; 3306 goto out; 3307 } 3308 3309 if (qcow2_opts->data_file) { 3310 if (version < 3) { 3311 error_setg(errp, "External data files are only supported with " 3312 "compatibility level 1.1 and above (use version=v3 or " 3313 "greater)"); 3314 ret = -EINVAL; 3315 goto out; 3316 } 3317 data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp); 3318 if (data_bs == NULL) { 3319 ret = -EIO; 3320 goto out; 3321 } 3322 } 3323 3324 /* Create BlockBackend to write to the image */ 3325 blk = blk_new(bdrv_get_aio_context(bs), 3326 BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 3327 ret = blk_insert_bs(blk, bs, errp); 3328 if (ret < 0) { 3329 goto out; 3330 } 3331 blk_set_allow_write_beyond_eof(blk, true); 3332 3333 /* Clear the protocol layer and preallocate it if necessary */ 3334 ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); 3335 if (ret < 0) { 3336 goto out; 3337 } 3338 3339 /* Write the header */ 3340 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 3341 header = g_malloc0(cluster_size); 3342 *header = (QCowHeader) { 3343 .magic = cpu_to_be32(QCOW_MAGIC), 3344 .version = cpu_to_be32(version), 3345 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 3346 .size = cpu_to_be64(0), 3347 .l1_table_offset = cpu_to_be64(0), 3348 .l1_size = cpu_to_be32(0), 3349 .refcount_table_offset = cpu_to_be64(cluster_size), 3350 .refcount_table_clusters = cpu_to_be32(1), 3351 .refcount_order = cpu_to_be32(refcount_order), 3352 .header_length = cpu_to_be32(sizeof(*header)), 3353 }; 3354 3355 /* We'll update this to correct value later */ 3356 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 3357 3358 if (qcow2_opts->lazy_refcounts) { 3359 header->compatible_features |= 3360 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 3361 } 3362 if (data_bs) { 3363 header->incompatible_features |= 3364 cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE); 3365 } 3366 if (qcow2_opts->data_file_raw) { 3367 header->autoclear_features |= 3368 cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW); 3369 } 3370 3371 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 3372 g_free(header); 3373 if (ret < 0) { 3374 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 3375 goto out; 3376 } 3377 3378 /* Write a refcount table with one refcount block */ 3379 refcount_table = g_malloc0(2 * cluster_size); 3380 refcount_table[0] = cpu_to_be64(2 * cluster_size); 3381 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 3382 g_free(refcount_table); 3383 3384 if (ret < 0) { 3385 error_setg_errno(errp, -ret, "Could not write refcount table"); 3386 goto out; 3387 } 3388 3389 blk_unref(blk); 3390 blk = NULL; 3391 3392 /* 3393 * And now open the image and make it consistent first (i.e. increase the 3394 * refcount of the cluster that is occupied by the header and the refcount 3395 * table) 3396 */ 3397 options = qdict_new(); 3398 qdict_put_str(options, "driver", "qcow2"); 3399 qdict_put_str(options, "file", bs->node_name); 3400 if (data_bs) { 3401 qdict_put_str(options, "data-file", data_bs->node_name); 3402 } 3403 blk = blk_new_open(NULL, NULL, options, 3404 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 3405 &local_err); 3406 if (blk == NULL) { 3407 error_propagate(errp, local_err); 3408 ret = -EIO; 3409 goto out; 3410 } 3411 3412 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 3413 if (ret < 0) { 3414 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 3415 "header and refcount table"); 3416 goto out; 3417 3418 } else if (ret != 0) { 3419 error_report("Huh, first cluster in empty image is already in use?"); 3420 abort(); 3421 } 3422 3423 /* Set the external data file if necessary */ 3424 if (data_bs) { 3425 BDRVQcow2State *s = blk_bs(blk)->opaque; 3426 s->image_data_file = g_strdup(data_bs->filename); 3427 } 3428 3429 /* Create a full header (including things like feature table) */ 3430 ret = qcow2_update_header(blk_bs(blk)); 3431 if (ret < 0) { 3432 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 3433 goto out; 3434 } 3435 3436 /* Okay, now that we have a valid image, let's give it the right size */ 3437 ret = blk_truncate(blk, qcow2_opts->size, qcow2_opts->preallocation, errp); 3438 if (ret < 0) { 3439 error_prepend(errp, "Could not resize image: "); 3440 goto out; 3441 } 3442 3443 /* Want a backing file? There you go.*/ 3444 if (qcow2_opts->has_backing_file) { 3445 const char *backing_format = NULL; 3446 3447 if (qcow2_opts->has_backing_fmt) { 3448 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); 3449 } 3450 3451 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, 3452 backing_format); 3453 if (ret < 0) { 3454 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 3455 "with format '%s'", qcow2_opts->backing_file, 3456 backing_format); 3457 goto out; 3458 } 3459 } 3460 3461 /* Want encryption? There you go. */ 3462 if (qcow2_opts->has_encrypt) { 3463 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); 3464 if (ret < 0) { 3465 goto out; 3466 } 3467 } 3468 3469 blk_unref(blk); 3470 blk = NULL; 3471 3472 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 3473 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 3474 * have to setup decryption context. We're not doing any I/O on the top 3475 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 3476 * not have effect. 3477 */ 3478 options = qdict_new(); 3479 qdict_put_str(options, "driver", "qcow2"); 3480 qdict_put_str(options, "file", bs->node_name); 3481 if (data_bs) { 3482 qdict_put_str(options, "data-file", data_bs->node_name); 3483 } 3484 blk = blk_new_open(NULL, NULL, options, 3485 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 3486 &local_err); 3487 if (blk == NULL) { 3488 error_propagate(errp, local_err); 3489 ret = -EIO; 3490 goto out; 3491 } 3492 3493 ret = 0; 3494 out: 3495 blk_unref(blk); 3496 bdrv_unref(bs); 3497 bdrv_unref(data_bs); 3498 return ret; 3499 } 3500 3501 static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts, 3502 Error **errp) 3503 { 3504 BlockdevCreateOptions *create_options = NULL; 3505 QDict *qdict; 3506 Visitor *v; 3507 BlockDriverState *bs = NULL; 3508 BlockDriverState *data_bs = NULL; 3509 Error *local_err = NULL; 3510 const char *val; 3511 int ret; 3512 3513 /* Only the keyval visitor supports the dotted syntax needed for 3514 * encryption, so go through a QDict before getting a QAPI type. Ignore 3515 * options meant for the protocol layer so that the visitor doesn't 3516 * complain. */ 3517 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, 3518 true); 3519 3520 /* Handle encryption options */ 3521 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 3522 if (val && !strcmp(val, "on")) { 3523 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 3524 } else if (val && !strcmp(val, "off")) { 3525 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 3526 } 3527 3528 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 3529 if (val && !strcmp(val, "aes")) { 3530 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 3531 } 3532 3533 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into 3534 * version=v2/v3 below. */ 3535 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); 3536 if (val && !strcmp(val, "0.10")) { 3537 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); 3538 } else if (val && !strcmp(val, "1.1")) { 3539 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); 3540 } 3541 3542 /* Change legacy command line options into QMP ones */ 3543 static const QDictRenames opt_renames[] = { 3544 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 3545 { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, 3546 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, 3547 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, 3548 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, 3549 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 3550 { BLOCK_OPT_COMPAT_LEVEL, "version" }, 3551 { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" }, 3552 { NULL, NULL }, 3553 }; 3554 3555 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 3556 ret = -EINVAL; 3557 goto finish; 3558 } 3559 3560 /* Create and open the file (protocol layer) */ 3561 ret = bdrv_create_file(filename, opts, errp); 3562 if (ret < 0) { 3563 goto finish; 3564 } 3565 3566 bs = bdrv_open(filename, NULL, NULL, 3567 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 3568 if (bs == NULL) { 3569 ret = -EIO; 3570 goto finish; 3571 } 3572 3573 /* Create and open an external data file (protocol layer) */ 3574 val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE); 3575 if (val) { 3576 ret = bdrv_create_file(val, opts, errp); 3577 if (ret < 0) { 3578 goto finish; 3579 } 3580 3581 data_bs = bdrv_open(val, NULL, NULL, 3582 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 3583 errp); 3584 if (data_bs == NULL) { 3585 ret = -EIO; 3586 goto finish; 3587 } 3588 3589 qdict_del(qdict, BLOCK_OPT_DATA_FILE); 3590 qdict_put_str(qdict, "data-file", data_bs->node_name); 3591 } 3592 3593 /* Set 'driver' and 'node' options */ 3594 qdict_put_str(qdict, "driver", "qcow2"); 3595 qdict_put_str(qdict, "file", bs->node_name); 3596 3597 /* Now get the QAPI type BlockdevCreateOptions */ 3598 v = qobject_input_visitor_new_flat_confused(qdict, errp); 3599 if (!v) { 3600 ret = -EINVAL; 3601 goto finish; 3602 } 3603 3604 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 3605 visit_free(v); 3606 3607 if (local_err) { 3608 error_propagate(errp, local_err); 3609 ret = -EINVAL; 3610 goto finish; 3611 } 3612 3613 /* Silently round up size */ 3614 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, 3615 BDRV_SECTOR_SIZE); 3616 3617 /* Create the qcow2 image (format layer) */ 3618 ret = qcow2_co_create(create_options, errp); 3619 if (ret < 0) { 3620 goto finish; 3621 } 3622 3623 ret = 0; 3624 finish: 3625 qobject_unref(qdict); 3626 bdrv_unref(bs); 3627 bdrv_unref(data_bs); 3628 qapi_free_BlockdevCreateOptions(create_options); 3629 return ret; 3630 } 3631 3632 3633 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3634 { 3635 int64_t nr; 3636 int res; 3637 3638 /* Clamp to image length, before checking status of underlying sectors */ 3639 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3640 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3641 } 3642 3643 if (!bytes) { 3644 return true; 3645 } 3646 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3647 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3648 } 3649 3650 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3651 int64_t offset, int bytes, BdrvRequestFlags flags) 3652 { 3653 int ret; 3654 BDRVQcow2State *s = bs->opaque; 3655 3656 uint32_t head = offset % s->cluster_size; 3657 uint32_t tail = (offset + bytes) % s->cluster_size; 3658 3659 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3660 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3661 tail = 0; 3662 } 3663 3664 if (head || tail) { 3665 uint64_t off; 3666 unsigned int nr; 3667 3668 assert(head + bytes <= s->cluster_size); 3669 3670 /* check whether remainder of cluster already reads as zero */ 3671 if (!(is_zero(bs, offset - head, head) && 3672 is_zero(bs, offset + bytes, 3673 tail ? s->cluster_size - tail : 0))) { 3674 return -ENOTSUP; 3675 } 3676 3677 qemu_co_mutex_lock(&s->lock); 3678 /* We can have new write after previous check */ 3679 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3680 bytes = s->cluster_size; 3681 nr = s->cluster_size; 3682 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3683 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3684 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3685 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3686 qemu_co_mutex_unlock(&s->lock); 3687 return -ENOTSUP; 3688 } 3689 } else { 3690 qemu_co_mutex_lock(&s->lock); 3691 } 3692 3693 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3694 3695 /* Whatever is left can use real zero clusters */ 3696 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3697 qemu_co_mutex_unlock(&s->lock); 3698 3699 return ret; 3700 } 3701 3702 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3703 int64_t offset, int bytes) 3704 { 3705 int ret; 3706 BDRVQcow2State *s = bs->opaque; 3707 3708 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3709 assert(bytes < s->cluster_size); 3710 /* Ignore partial clusters, except for the special case of the 3711 * complete partial cluster at the end of an unaligned file */ 3712 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3713 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3714 return -ENOTSUP; 3715 } 3716 } 3717 3718 qemu_co_mutex_lock(&s->lock); 3719 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3720 false); 3721 qemu_co_mutex_unlock(&s->lock); 3722 return ret; 3723 } 3724 3725 static int coroutine_fn 3726 qcow2_co_copy_range_from(BlockDriverState *bs, 3727 BdrvChild *src, uint64_t src_offset, 3728 BdrvChild *dst, uint64_t dst_offset, 3729 uint64_t bytes, BdrvRequestFlags read_flags, 3730 BdrvRequestFlags write_flags) 3731 { 3732 BDRVQcow2State *s = bs->opaque; 3733 int ret; 3734 unsigned int cur_bytes; /* number of bytes in current iteration */ 3735 BdrvChild *child = NULL; 3736 BdrvRequestFlags cur_write_flags; 3737 3738 assert(!bs->encrypted); 3739 qemu_co_mutex_lock(&s->lock); 3740 3741 while (bytes != 0) { 3742 uint64_t copy_offset = 0; 3743 /* prepare next request */ 3744 cur_bytes = MIN(bytes, INT_MAX); 3745 cur_write_flags = write_flags; 3746 3747 ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, ©_offset); 3748 if (ret < 0) { 3749 goto out; 3750 } 3751 3752 switch (ret) { 3753 case QCOW2_CLUSTER_UNALLOCATED: 3754 if (bs->backing && bs->backing->bs) { 3755 int64_t backing_length = bdrv_getlength(bs->backing->bs); 3756 if (src_offset >= backing_length) { 3757 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3758 } else { 3759 child = bs->backing; 3760 cur_bytes = MIN(cur_bytes, backing_length - src_offset); 3761 copy_offset = src_offset; 3762 } 3763 } else { 3764 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3765 } 3766 break; 3767 3768 case QCOW2_CLUSTER_ZERO_PLAIN: 3769 case QCOW2_CLUSTER_ZERO_ALLOC: 3770 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3771 break; 3772 3773 case QCOW2_CLUSTER_COMPRESSED: 3774 ret = -ENOTSUP; 3775 goto out; 3776 3777 case QCOW2_CLUSTER_NORMAL: 3778 child = s->data_file; 3779 copy_offset += offset_into_cluster(s, src_offset); 3780 if ((copy_offset & 511) != 0) { 3781 ret = -EIO; 3782 goto out; 3783 } 3784 break; 3785 3786 default: 3787 abort(); 3788 } 3789 qemu_co_mutex_unlock(&s->lock); 3790 ret = bdrv_co_copy_range_from(child, 3791 copy_offset, 3792 dst, dst_offset, 3793 cur_bytes, read_flags, cur_write_flags); 3794 qemu_co_mutex_lock(&s->lock); 3795 if (ret < 0) { 3796 goto out; 3797 } 3798 3799 bytes -= cur_bytes; 3800 src_offset += cur_bytes; 3801 dst_offset += cur_bytes; 3802 } 3803 ret = 0; 3804 3805 out: 3806 qemu_co_mutex_unlock(&s->lock); 3807 return ret; 3808 } 3809 3810 static int coroutine_fn 3811 qcow2_co_copy_range_to(BlockDriverState *bs, 3812 BdrvChild *src, uint64_t src_offset, 3813 BdrvChild *dst, uint64_t dst_offset, 3814 uint64_t bytes, BdrvRequestFlags read_flags, 3815 BdrvRequestFlags write_flags) 3816 { 3817 BDRVQcow2State *s = bs->opaque; 3818 int offset_in_cluster; 3819 int ret; 3820 unsigned int cur_bytes; /* number of sectors in current iteration */ 3821 uint64_t cluster_offset; 3822 QCowL2Meta *l2meta = NULL; 3823 3824 assert(!bs->encrypted); 3825 3826 qemu_co_mutex_lock(&s->lock); 3827 3828 while (bytes != 0) { 3829 3830 l2meta = NULL; 3831 3832 offset_in_cluster = offset_into_cluster(s, dst_offset); 3833 cur_bytes = MIN(bytes, INT_MAX); 3834 3835 /* TODO: 3836 * If src->bs == dst->bs, we could simply copy by incrementing 3837 * the refcnt, without copying user data. 3838 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ 3839 ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes, 3840 &cluster_offset, &l2meta); 3841 if (ret < 0) { 3842 goto fail; 3843 } 3844 3845 assert((cluster_offset & 511) == 0); 3846 3847 ret = qcow2_pre_write_overlap_check(bs, 0, 3848 cluster_offset + offset_in_cluster, cur_bytes, true); 3849 if (ret < 0) { 3850 goto fail; 3851 } 3852 3853 qemu_co_mutex_unlock(&s->lock); 3854 ret = bdrv_co_copy_range_to(src, src_offset, 3855 s->data_file, 3856 cluster_offset + offset_in_cluster, 3857 cur_bytes, read_flags, write_flags); 3858 qemu_co_mutex_lock(&s->lock); 3859 if (ret < 0) { 3860 goto fail; 3861 } 3862 3863 ret = qcow2_handle_l2meta(bs, &l2meta, true); 3864 if (ret) { 3865 goto fail; 3866 } 3867 3868 bytes -= cur_bytes; 3869 src_offset += cur_bytes; 3870 dst_offset += cur_bytes; 3871 } 3872 ret = 0; 3873 3874 fail: 3875 qcow2_handle_l2meta(bs, &l2meta, false); 3876 3877 qemu_co_mutex_unlock(&s->lock); 3878 3879 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 3880 3881 return ret; 3882 } 3883 3884 static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, 3885 PreallocMode prealloc, Error **errp) 3886 { 3887 BDRVQcow2State *s = bs->opaque; 3888 uint64_t old_length; 3889 int64_t new_l1_size; 3890 int ret; 3891 QDict *options; 3892 3893 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3894 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3895 { 3896 error_setg(errp, "Unsupported preallocation mode '%s'", 3897 PreallocMode_str(prealloc)); 3898 return -ENOTSUP; 3899 } 3900 3901 if (offset & 511) { 3902 error_setg(errp, "The new size must be a multiple of 512"); 3903 return -EINVAL; 3904 } 3905 3906 qemu_co_mutex_lock(&s->lock); 3907 3908 /* cannot proceed if image has snapshots */ 3909 if (s->nb_snapshots) { 3910 error_setg(errp, "Can't resize an image which has snapshots"); 3911 ret = -ENOTSUP; 3912 goto fail; 3913 } 3914 3915 /* cannot proceed if image has bitmaps */ 3916 if (qcow2_truncate_bitmaps_check(bs, errp)) { 3917 ret = -ENOTSUP; 3918 goto fail; 3919 } 3920 3921 old_length = bs->total_sectors * BDRV_SECTOR_SIZE; 3922 new_l1_size = size_to_l1(s, offset); 3923 3924 if (offset < old_length) { 3925 int64_t last_cluster, old_file_size; 3926 if (prealloc != PREALLOC_MODE_OFF) { 3927 error_setg(errp, 3928 "Preallocation can't be used for shrinking an image"); 3929 ret = -EINVAL; 3930 goto fail; 3931 } 3932 3933 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3934 old_length - ROUND_UP(offset, 3935 s->cluster_size), 3936 QCOW2_DISCARD_ALWAYS, true); 3937 if (ret < 0) { 3938 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3939 goto fail; 3940 } 3941 3942 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3943 if (ret < 0) { 3944 error_setg_errno(errp, -ret, 3945 "Failed to reduce the number of L2 tables"); 3946 goto fail; 3947 } 3948 3949 ret = qcow2_shrink_reftable(bs); 3950 if (ret < 0) { 3951 error_setg_errno(errp, -ret, 3952 "Failed to discard unused refblocks"); 3953 goto fail; 3954 } 3955 3956 old_file_size = bdrv_getlength(bs->file->bs); 3957 if (old_file_size < 0) { 3958 error_setg_errno(errp, -old_file_size, 3959 "Failed to inquire current file length"); 3960 ret = old_file_size; 3961 goto fail; 3962 } 3963 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3964 if (last_cluster < 0) { 3965 error_setg_errno(errp, -last_cluster, 3966 "Failed to find the last cluster"); 3967 ret = last_cluster; 3968 goto fail; 3969 } 3970 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3971 Error *local_err = NULL; 3972 3973 bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3974 PREALLOC_MODE_OFF, &local_err); 3975 if (local_err) { 3976 warn_reportf_err(local_err, 3977 "Failed to truncate the tail of the image: "); 3978 } 3979 } 3980 } else { 3981 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3982 if (ret < 0) { 3983 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3984 goto fail; 3985 } 3986 } 3987 3988 switch (prealloc) { 3989 case PREALLOC_MODE_OFF: 3990 if (has_data_file(bs)) { 3991 ret = bdrv_co_truncate(s->data_file, offset, prealloc, errp); 3992 if (ret < 0) { 3993 goto fail; 3994 } 3995 } 3996 break; 3997 3998 case PREALLOC_MODE_METADATA: 3999 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 4000 if (ret < 0) { 4001 goto fail; 4002 } 4003 break; 4004 4005 case PREALLOC_MODE_FALLOC: 4006 case PREALLOC_MODE_FULL: 4007 { 4008 int64_t allocation_start, host_offset, guest_offset; 4009 int64_t clusters_allocated; 4010 int64_t old_file_size, new_file_size; 4011 uint64_t nb_new_data_clusters, nb_new_l2_tables; 4012 4013 /* With a data file, preallocation means just allocating the metadata 4014 * and forwarding the truncate request to the data file */ 4015 if (has_data_file(bs)) { 4016 ret = preallocate_co(bs, old_length, offset, prealloc, errp); 4017 if (ret < 0) { 4018 goto fail; 4019 } 4020 break; 4021 } 4022 4023 old_file_size = bdrv_getlength(bs->file->bs); 4024 if (old_file_size < 0) { 4025 error_setg_errno(errp, -old_file_size, 4026 "Failed to inquire current file length"); 4027 ret = old_file_size; 4028 goto fail; 4029 } 4030 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 4031 4032 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 4033 s->cluster_size); 4034 4035 /* This is an overestimation; we will not actually allocate space for 4036 * these in the file but just make sure the new refcount structures are 4037 * able to cover them so we will not have to allocate new refblocks 4038 * while entering the data blocks in the potentially new L2 tables. 4039 * (We do not actually care where the L2 tables are placed. Maybe they 4040 * are already allocated or they can be placed somewhere before 4041 * @old_file_size. It does not matter because they will be fully 4042 * allocated automatically, so they do not need to be covered by the 4043 * preallocation. All that matters is that we will not have to allocate 4044 * new refcount structures for them.) */ 4045 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 4046 s->cluster_size / sizeof(uint64_t)); 4047 /* The cluster range may not be aligned to L2 boundaries, so add one L2 4048 * table for a potential head/tail */ 4049 nb_new_l2_tables++; 4050 4051 allocation_start = qcow2_refcount_area(bs, old_file_size, 4052 nb_new_data_clusters + 4053 nb_new_l2_tables, 4054 true, 0, 0); 4055 if (allocation_start < 0) { 4056 error_setg_errno(errp, -allocation_start, 4057 "Failed to resize refcount structures"); 4058 ret = allocation_start; 4059 goto fail; 4060 } 4061 4062 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 4063 nb_new_data_clusters); 4064 if (clusters_allocated < 0) { 4065 error_setg_errno(errp, -clusters_allocated, 4066 "Failed to allocate data clusters"); 4067 ret = clusters_allocated; 4068 goto fail; 4069 } 4070 4071 assert(clusters_allocated == nb_new_data_clusters); 4072 4073 /* Allocate the data area */ 4074 new_file_size = allocation_start + 4075 nb_new_data_clusters * s->cluster_size; 4076 ret = bdrv_co_truncate(bs->file, new_file_size, prealloc, errp); 4077 if (ret < 0) { 4078 error_prepend(errp, "Failed to resize underlying file: "); 4079 qcow2_free_clusters(bs, allocation_start, 4080 nb_new_data_clusters * s->cluster_size, 4081 QCOW2_DISCARD_OTHER); 4082 goto fail; 4083 } 4084 4085 /* Create the necessary L2 entries */ 4086 host_offset = allocation_start; 4087 guest_offset = old_length; 4088 while (nb_new_data_clusters) { 4089 int64_t nb_clusters = MIN( 4090 nb_new_data_clusters, 4091 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 4092 QCowL2Meta allocation = { 4093 .offset = guest_offset, 4094 .alloc_offset = host_offset, 4095 .nb_clusters = nb_clusters, 4096 }; 4097 qemu_co_queue_init(&allocation.dependent_requests); 4098 4099 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 4100 if (ret < 0) { 4101 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 4102 qcow2_free_clusters(bs, host_offset, 4103 nb_new_data_clusters * s->cluster_size, 4104 QCOW2_DISCARD_OTHER); 4105 goto fail; 4106 } 4107 4108 guest_offset += nb_clusters * s->cluster_size; 4109 host_offset += nb_clusters * s->cluster_size; 4110 nb_new_data_clusters -= nb_clusters; 4111 } 4112 break; 4113 } 4114 4115 default: 4116 g_assert_not_reached(); 4117 } 4118 4119 if (prealloc != PREALLOC_MODE_OFF) { 4120 /* Flush metadata before actually changing the image size */ 4121 ret = qcow2_write_caches(bs); 4122 if (ret < 0) { 4123 error_setg_errno(errp, -ret, 4124 "Failed to flush the preallocated area to disk"); 4125 goto fail; 4126 } 4127 } 4128 4129 bs->total_sectors = offset / BDRV_SECTOR_SIZE; 4130 4131 /* write updated header.size */ 4132 offset = cpu_to_be64(offset); 4133 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 4134 &offset, sizeof(uint64_t)); 4135 if (ret < 0) { 4136 error_setg_errno(errp, -ret, "Failed to update the image size"); 4137 goto fail; 4138 } 4139 4140 s->l1_vm_state_index = new_l1_size; 4141 4142 /* Update cache sizes */ 4143 options = qdict_clone_shallow(bs->options); 4144 ret = qcow2_update_options(bs, options, s->flags, errp); 4145 qobject_unref(options); 4146 if (ret < 0) { 4147 goto fail; 4148 } 4149 ret = 0; 4150 fail: 4151 qemu_co_mutex_unlock(&s->lock); 4152 return ret; 4153 } 4154 4155 /* XXX: put compressed sectors first, then all the cluster aligned 4156 tables to avoid losing bytes in alignment */ 4157 static coroutine_fn int 4158 qcow2_co_pwritev_compressed_part(BlockDriverState *bs, 4159 uint64_t offset, uint64_t bytes, 4160 QEMUIOVector *qiov, size_t qiov_offset) 4161 { 4162 BDRVQcow2State *s = bs->opaque; 4163 int ret; 4164 ssize_t out_len; 4165 uint8_t *buf, *out_buf; 4166 uint64_t cluster_offset; 4167 4168 if (has_data_file(bs)) { 4169 return -ENOTSUP; 4170 } 4171 4172 if (bytes == 0) { 4173 /* align end of file to a sector boundary to ease reading with 4174 sector based I/Os */ 4175 int64_t len = bdrv_getlength(bs->file->bs); 4176 if (len < 0) { 4177 return len; 4178 } 4179 return bdrv_co_truncate(bs->file, len, PREALLOC_MODE_OFF, NULL); 4180 } 4181 4182 if (offset_into_cluster(s, offset)) { 4183 return -EINVAL; 4184 } 4185 4186 buf = qemu_blockalign(bs, s->cluster_size); 4187 if (bytes != s->cluster_size) { 4188 if (bytes > s->cluster_size || 4189 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 4190 { 4191 qemu_vfree(buf); 4192 return -EINVAL; 4193 } 4194 /* Zero-pad last write if image size is not cluster aligned */ 4195 memset(buf + bytes, 0, s->cluster_size - bytes); 4196 } 4197 qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes); 4198 4199 out_buf = g_malloc(s->cluster_size); 4200 4201 out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1, 4202 buf, s->cluster_size); 4203 if (out_len == -ENOMEM) { 4204 /* could not compress: write normal cluster */ 4205 ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0); 4206 if (ret < 0) { 4207 goto fail; 4208 } 4209 goto success; 4210 } else if (out_len < 0) { 4211 ret = -EINVAL; 4212 goto fail; 4213 } 4214 4215 qemu_co_mutex_lock(&s->lock); 4216 ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len, 4217 &cluster_offset); 4218 if (ret < 0) { 4219 qemu_co_mutex_unlock(&s->lock); 4220 goto fail; 4221 } 4222 4223 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true); 4224 qemu_co_mutex_unlock(&s->lock); 4225 if (ret < 0) { 4226 goto fail; 4227 } 4228 4229 BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED); 4230 ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0); 4231 if (ret < 0) { 4232 goto fail; 4233 } 4234 success: 4235 ret = 0; 4236 fail: 4237 qemu_vfree(buf); 4238 g_free(out_buf); 4239 return ret; 4240 } 4241 4242 static int coroutine_fn 4243 qcow2_co_preadv_compressed(BlockDriverState *bs, 4244 uint64_t file_cluster_offset, 4245 uint64_t offset, 4246 uint64_t bytes, 4247 QEMUIOVector *qiov, 4248 size_t qiov_offset) 4249 { 4250 BDRVQcow2State *s = bs->opaque; 4251 int ret = 0, csize, nb_csectors; 4252 uint64_t coffset; 4253 uint8_t *buf, *out_buf; 4254 int offset_in_cluster = offset_into_cluster(s, offset); 4255 4256 coffset = file_cluster_offset & s->cluster_offset_mask; 4257 nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1; 4258 csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - 4259 (coffset & ~QCOW2_COMPRESSED_SECTOR_MASK); 4260 4261 buf = g_try_malloc(csize); 4262 if (!buf) { 4263 return -ENOMEM; 4264 } 4265 4266 out_buf = qemu_blockalign(bs, s->cluster_size); 4267 4268 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 4269 ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0); 4270 if (ret < 0) { 4271 goto fail; 4272 } 4273 4274 if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) { 4275 ret = -EIO; 4276 goto fail; 4277 } 4278 4279 qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes); 4280 4281 fail: 4282 qemu_vfree(out_buf); 4283 g_free(buf); 4284 4285 return ret; 4286 } 4287 4288 static int make_completely_empty(BlockDriverState *bs) 4289 { 4290 BDRVQcow2State *s = bs->opaque; 4291 Error *local_err = NULL; 4292 int ret, l1_clusters; 4293 int64_t offset; 4294 uint64_t *new_reftable = NULL; 4295 uint64_t rt_entry, l1_size2; 4296 struct { 4297 uint64_t l1_offset; 4298 uint64_t reftable_offset; 4299 uint32_t reftable_clusters; 4300 } QEMU_PACKED l1_ofs_rt_ofs_cls; 4301 4302 ret = qcow2_cache_empty(bs, s->l2_table_cache); 4303 if (ret < 0) { 4304 goto fail; 4305 } 4306 4307 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 4308 if (ret < 0) { 4309 goto fail; 4310 } 4311 4312 /* Refcounts will be broken utterly */ 4313 ret = qcow2_mark_dirty(bs); 4314 if (ret < 0) { 4315 goto fail; 4316 } 4317 4318 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4319 4320 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4321 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 4322 4323 /* After this call, neither the in-memory nor the on-disk refcount 4324 * information accurately describe the actual references */ 4325 4326 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 4327 l1_clusters * s->cluster_size, 0); 4328 if (ret < 0) { 4329 goto fail_broken_refcounts; 4330 } 4331 memset(s->l1_table, 0, l1_size2); 4332 4333 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 4334 4335 /* Overwrite enough clusters at the beginning of the sectors to place 4336 * the refcount table, a refcount block and the L1 table in; this may 4337 * overwrite parts of the existing refcount and L1 table, which is not 4338 * an issue because the dirty flag is set, complete data loss is in fact 4339 * desired and partial data loss is consequently fine as well */ 4340 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 4341 (2 + l1_clusters) * s->cluster_size, 0); 4342 /* This call (even if it failed overall) may have overwritten on-disk 4343 * refcount structures; in that case, the in-memory refcount information 4344 * will probably differ from the on-disk information which makes the BDS 4345 * unusable */ 4346 if (ret < 0) { 4347 goto fail_broken_refcounts; 4348 } 4349 4350 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4351 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 4352 4353 /* "Create" an empty reftable (one cluster) directly after the image 4354 * header and an empty L1 table three clusters after the image header; 4355 * the cluster between those two will be used as the first refblock */ 4356 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 4357 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 4358 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 4359 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 4360 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 4361 if (ret < 0) { 4362 goto fail_broken_refcounts; 4363 } 4364 4365 s->l1_table_offset = 3 * s->cluster_size; 4366 4367 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 4368 if (!new_reftable) { 4369 ret = -ENOMEM; 4370 goto fail_broken_refcounts; 4371 } 4372 4373 s->refcount_table_offset = s->cluster_size; 4374 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 4375 s->max_refcount_table_index = 0; 4376 4377 g_free(s->refcount_table); 4378 s->refcount_table = new_reftable; 4379 new_reftable = NULL; 4380 4381 /* Now the in-memory refcount information again corresponds to the on-disk 4382 * information (reftable is empty and no refblocks (the refblock cache is 4383 * empty)); however, this means some clusters (e.g. the image header) are 4384 * referenced, but not refcounted, but the normal qcow2 code assumes that 4385 * the in-memory information is always correct */ 4386 4387 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 4388 4389 /* Enter the first refblock into the reftable */ 4390 rt_entry = cpu_to_be64(2 * s->cluster_size); 4391 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 4392 &rt_entry, sizeof(rt_entry)); 4393 if (ret < 0) { 4394 goto fail_broken_refcounts; 4395 } 4396 s->refcount_table[0] = 2 * s->cluster_size; 4397 4398 s->free_cluster_index = 0; 4399 assert(3 + l1_clusters <= s->refcount_block_size); 4400 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 4401 if (offset < 0) { 4402 ret = offset; 4403 goto fail_broken_refcounts; 4404 } else if (offset > 0) { 4405 error_report("First cluster in emptied image is in use"); 4406 abort(); 4407 } 4408 4409 /* Now finally the in-memory information corresponds to the on-disk 4410 * structures and is correct */ 4411 ret = qcow2_mark_clean(bs); 4412 if (ret < 0) { 4413 goto fail; 4414 } 4415 4416 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 4417 PREALLOC_MODE_OFF, &local_err); 4418 if (ret < 0) { 4419 error_report_err(local_err); 4420 goto fail; 4421 } 4422 4423 return 0; 4424 4425 fail_broken_refcounts: 4426 /* The BDS is unusable at this point. If we wanted to make it usable, we 4427 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 4428 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 4429 * again. However, because the functions which could have caused this error 4430 * path to be taken are used by those functions as well, it's very likely 4431 * that that sequence will fail as well. Therefore, just eject the BDS. */ 4432 bs->drv = NULL; 4433 4434 fail: 4435 g_free(new_reftable); 4436 return ret; 4437 } 4438 4439 static int qcow2_make_empty(BlockDriverState *bs) 4440 { 4441 BDRVQcow2State *s = bs->opaque; 4442 uint64_t offset, end_offset; 4443 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 4444 int l1_clusters, ret = 0; 4445 4446 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4447 4448 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 4449 3 + l1_clusters <= s->refcount_block_size && 4450 s->crypt_method_header != QCOW_CRYPT_LUKS && 4451 !has_data_file(bs)) { 4452 /* The following function only works for qcow2 v3 images (it 4453 * requires the dirty flag) and only as long as there are no 4454 * features that reserve extra clusters (such as snapshots, 4455 * LUKS header, or persistent bitmaps), because it completely 4456 * empties the image. Furthermore, the L1 table and three 4457 * additional clusters (image header, refcount table, one 4458 * refcount block) have to fit inside one refcount block. It 4459 * only resets the image file, i.e. does not work with an 4460 * external data file. */ 4461 return make_completely_empty(bs); 4462 } 4463 4464 /* This fallback code simply discards every active cluster; this is slow, 4465 * but works in all cases */ 4466 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 4467 for (offset = 0; offset < end_offset; offset += step) { 4468 /* As this function is generally used after committing an external 4469 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 4470 * default action for this kind of discard is to pass the discard, 4471 * which will ideally result in an actually smaller image file, as 4472 * is probably desired. */ 4473 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 4474 QCOW2_DISCARD_SNAPSHOT, true); 4475 if (ret < 0) { 4476 break; 4477 } 4478 } 4479 4480 return ret; 4481 } 4482 4483 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 4484 { 4485 BDRVQcow2State *s = bs->opaque; 4486 int ret; 4487 4488 qemu_co_mutex_lock(&s->lock); 4489 ret = qcow2_write_caches(bs); 4490 qemu_co_mutex_unlock(&s->lock); 4491 4492 return ret; 4493 } 4494 4495 static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block, 4496 size_t headerlen, void *opaque, Error **errp) 4497 { 4498 size_t *headerlenp = opaque; 4499 4500 /* Stash away the payload size */ 4501 *headerlenp = headerlen; 4502 return 0; 4503 } 4504 4505 static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block, 4506 size_t offset, const uint8_t *buf, size_t buflen, 4507 void *opaque, Error **errp) 4508 { 4509 /* Discard the bytes, we're not actually writing to an image */ 4510 return buflen; 4511 } 4512 4513 /* Determine the number of bytes for the LUKS payload */ 4514 static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len, 4515 Error **errp) 4516 { 4517 QDict *opts_qdict; 4518 QDict *cryptoopts_qdict; 4519 QCryptoBlockCreateOptions *cryptoopts; 4520 QCryptoBlock *crypto; 4521 4522 /* Extract "encrypt." options into a qdict */ 4523 opts_qdict = qemu_opts_to_qdict(opts, NULL); 4524 qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt."); 4525 qobject_unref(opts_qdict); 4526 4527 /* Build QCryptoBlockCreateOptions object from qdict */ 4528 qdict_put_str(cryptoopts_qdict, "format", "luks"); 4529 cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp); 4530 qobject_unref(cryptoopts_qdict); 4531 if (!cryptoopts) { 4532 return false; 4533 } 4534 4535 /* Fake LUKS creation in order to determine the payload size */ 4536 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 4537 qcow2_measure_crypto_hdr_init_func, 4538 qcow2_measure_crypto_hdr_write_func, 4539 len, errp); 4540 qapi_free_QCryptoBlockCreateOptions(cryptoopts); 4541 if (!crypto) { 4542 return false; 4543 } 4544 4545 qcrypto_block_free(crypto); 4546 return true; 4547 } 4548 4549 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 4550 Error **errp) 4551 { 4552 Error *local_err = NULL; 4553 BlockMeasureInfo *info; 4554 uint64_t required = 0; /* bytes that contribute to required size */ 4555 uint64_t virtual_size; /* disk size as seen by guest */ 4556 uint64_t refcount_bits; 4557 uint64_t l2_tables; 4558 uint64_t luks_payload_size = 0; 4559 size_t cluster_size; 4560 int version; 4561 char *optstr; 4562 PreallocMode prealloc; 4563 bool has_backing_file; 4564 bool has_luks; 4565 4566 /* Parse image creation options */ 4567 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 4568 if (local_err) { 4569 goto err; 4570 } 4571 4572 version = qcow2_opt_get_version_del(opts, &local_err); 4573 if (local_err) { 4574 goto err; 4575 } 4576 4577 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 4578 if (local_err) { 4579 goto err; 4580 } 4581 4582 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 4583 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 4584 PREALLOC_MODE_OFF, &local_err); 4585 g_free(optstr); 4586 if (local_err) { 4587 goto err; 4588 } 4589 4590 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 4591 has_backing_file = !!optstr; 4592 g_free(optstr); 4593 4594 optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 4595 has_luks = optstr && strcmp(optstr, "luks") == 0; 4596 g_free(optstr); 4597 4598 if (has_luks) { 4599 size_t headerlen; 4600 4601 if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) { 4602 goto err; 4603 } 4604 4605 luks_payload_size = ROUND_UP(headerlen, cluster_size); 4606 } 4607 4608 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 4609 virtual_size = ROUND_UP(virtual_size, cluster_size); 4610 4611 /* Check that virtual disk size is valid */ 4612 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 4613 cluster_size / sizeof(uint64_t)); 4614 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 4615 error_setg(&local_err, "The image size is too large " 4616 "(try using a larger cluster size)"); 4617 goto err; 4618 } 4619 4620 /* Account for input image */ 4621 if (in_bs) { 4622 int64_t ssize = bdrv_getlength(in_bs); 4623 if (ssize < 0) { 4624 error_setg_errno(&local_err, -ssize, 4625 "Unable to get image virtual_size"); 4626 goto err; 4627 } 4628 4629 virtual_size = ROUND_UP(ssize, cluster_size); 4630 4631 if (has_backing_file) { 4632 /* We don't how much of the backing chain is shared by the input 4633 * image and the new image file. In the worst case the new image's 4634 * backing file has nothing in common with the input image. Be 4635 * conservative and assume all clusters need to be written. 4636 */ 4637 required = virtual_size; 4638 } else { 4639 int64_t offset; 4640 int64_t pnum = 0; 4641 4642 for (offset = 0; offset < ssize; offset += pnum) { 4643 int ret; 4644 4645 ret = bdrv_block_status_above(in_bs, NULL, offset, 4646 ssize - offset, &pnum, NULL, 4647 NULL); 4648 if (ret < 0) { 4649 error_setg_errno(&local_err, -ret, 4650 "Unable to get block status"); 4651 goto err; 4652 } 4653 4654 if (ret & BDRV_BLOCK_ZERO) { 4655 /* Skip zero regions (safe with no backing file) */ 4656 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 4657 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 4658 /* Extend pnum to end of cluster for next iteration */ 4659 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 4660 4661 /* Count clusters we've seen */ 4662 required += offset % cluster_size + pnum; 4663 } 4664 } 4665 } 4666 } 4667 4668 /* Take into account preallocation. Nothing special is needed for 4669 * PREALLOC_MODE_METADATA since metadata is always counted. 4670 */ 4671 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 4672 required = virtual_size; 4673 } 4674 4675 info = g_new(BlockMeasureInfo, 1); 4676 info->fully_allocated = 4677 qcow2_calc_prealloc_size(virtual_size, cluster_size, 4678 ctz32(refcount_bits)) + luks_payload_size; 4679 4680 /* Remove data clusters that are not required. This overestimates the 4681 * required size because metadata needed for the fully allocated file is 4682 * still counted. 4683 */ 4684 info->required = info->fully_allocated - virtual_size + required; 4685 return info; 4686 4687 err: 4688 error_propagate(errp, local_err); 4689 return NULL; 4690 } 4691 4692 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4693 { 4694 BDRVQcow2State *s = bs->opaque; 4695 bdi->unallocated_blocks_are_zero = true; 4696 bdi->cluster_size = s->cluster_size; 4697 bdi->vm_state_offset = qcow2_vm_state_offset(s); 4698 return 0; 4699 } 4700 4701 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, 4702 Error **errp) 4703 { 4704 BDRVQcow2State *s = bs->opaque; 4705 ImageInfoSpecific *spec_info; 4706 QCryptoBlockInfo *encrypt_info = NULL; 4707 Error *local_err = NULL; 4708 4709 if (s->crypto != NULL) { 4710 encrypt_info = qcrypto_block_get_info(s->crypto, &local_err); 4711 if (local_err) { 4712 error_propagate(errp, local_err); 4713 return NULL; 4714 } 4715 } 4716 4717 spec_info = g_new(ImageInfoSpecific, 1); 4718 *spec_info = (ImageInfoSpecific){ 4719 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 4720 .u.qcow2.data = g_new0(ImageInfoSpecificQCow2, 1), 4721 }; 4722 if (s->qcow_version == 2) { 4723 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4724 .compat = g_strdup("0.10"), 4725 .refcount_bits = s->refcount_bits, 4726 }; 4727 } else if (s->qcow_version == 3) { 4728 Qcow2BitmapInfoList *bitmaps; 4729 bitmaps = qcow2_get_bitmap_info_list(bs, &local_err); 4730 if (local_err) { 4731 error_propagate(errp, local_err); 4732 qapi_free_ImageInfoSpecific(spec_info); 4733 return NULL; 4734 } 4735 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4736 .compat = g_strdup("1.1"), 4737 .lazy_refcounts = s->compatible_features & 4738 QCOW2_COMPAT_LAZY_REFCOUNTS, 4739 .has_lazy_refcounts = true, 4740 .corrupt = s->incompatible_features & 4741 QCOW2_INCOMPAT_CORRUPT, 4742 .has_corrupt = true, 4743 .refcount_bits = s->refcount_bits, 4744 .has_bitmaps = !!bitmaps, 4745 .bitmaps = bitmaps, 4746 .has_data_file = !!s->image_data_file, 4747 .data_file = g_strdup(s->image_data_file), 4748 .has_data_file_raw = has_data_file(bs), 4749 .data_file_raw = data_file_is_raw(bs), 4750 }; 4751 } else { 4752 /* if this assertion fails, this probably means a new version was 4753 * added without having it covered here */ 4754 assert(false); 4755 } 4756 4757 if (encrypt_info) { 4758 ImageInfoSpecificQCow2Encryption *qencrypt = 4759 g_new(ImageInfoSpecificQCow2Encryption, 1); 4760 switch (encrypt_info->format) { 4761 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 4762 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 4763 break; 4764 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 4765 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 4766 qencrypt->u.luks = encrypt_info->u.luks; 4767 break; 4768 default: 4769 abort(); 4770 } 4771 /* Since we did shallow copy above, erase any pointers 4772 * in the original info */ 4773 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 4774 qapi_free_QCryptoBlockInfo(encrypt_info); 4775 4776 spec_info->u.qcow2.data->has_encrypt = true; 4777 spec_info->u.qcow2.data->encrypt = qencrypt; 4778 } 4779 4780 return spec_info; 4781 } 4782 4783 static int qcow2_has_zero_init(BlockDriverState *bs) 4784 { 4785 BDRVQcow2State *s = bs->opaque; 4786 bool preallocated; 4787 4788 if (qemu_in_coroutine()) { 4789 qemu_co_mutex_lock(&s->lock); 4790 } 4791 /* 4792 * Check preallocation status: Preallocated images have all L2 4793 * tables allocated, nonpreallocated images have none. It is 4794 * therefore enough to check the first one. 4795 */ 4796 preallocated = s->l1_size > 0 && s->l1_table[0] != 0; 4797 if (qemu_in_coroutine()) { 4798 qemu_co_mutex_unlock(&s->lock); 4799 } 4800 4801 if (!preallocated) { 4802 return 1; 4803 } else if (bs->encrypted) { 4804 return 0; 4805 } else { 4806 return bdrv_has_zero_init(s->data_file->bs); 4807 } 4808 } 4809 4810 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4811 int64_t pos) 4812 { 4813 BDRVQcow2State *s = bs->opaque; 4814 4815 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 4816 return bs->drv->bdrv_co_pwritev_part(bs, qcow2_vm_state_offset(s) + pos, 4817 qiov->size, qiov, 0, 0); 4818 } 4819 4820 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4821 int64_t pos) 4822 { 4823 BDRVQcow2State *s = bs->opaque; 4824 4825 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 4826 return bs->drv->bdrv_co_preadv_part(bs, qcow2_vm_state_offset(s) + pos, 4827 qiov->size, qiov, 0, 0); 4828 } 4829 4830 /* 4831 * Downgrades an image's version. To achieve this, any incompatible features 4832 * have to be removed. 4833 */ 4834 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 4835 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 4836 Error **errp) 4837 { 4838 BDRVQcow2State *s = bs->opaque; 4839 int current_version = s->qcow_version; 4840 int ret; 4841 4842 /* This is qcow2_downgrade(), not qcow2_upgrade() */ 4843 assert(target_version < current_version); 4844 4845 /* There are no other versions (now) that you can downgrade to */ 4846 assert(target_version == 2); 4847 4848 if (s->refcount_order != 4) { 4849 error_setg(errp, "compat=0.10 requires refcount_bits=16"); 4850 return -ENOTSUP; 4851 } 4852 4853 if (has_data_file(bs)) { 4854 error_setg(errp, "Cannot downgrade an image with a data file"); 4855 return -ENOTSUP; 4856 } 4857 4858 /* clear incompatible features */ 4859 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 4860 ret = qcow2_mark_clean(bs); 4861 if (ret < 0) { 4862 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4863 return ret; 4864 } 4865 } 4866 4867 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 4868 * the first place; if that happens nonetheless, returning -ENOTSUP is the 4869 * best thing to do anyway */ 4870 4871 if (s->incompatible_features) { 4872 error_setg(errp, "Cannot downgrade an image with incompatible features " 4873 "%#" PRIx64 " set", s->incompatible_features); 4874 return -ENOTSUP; 4875 } 4876 4877 /* since we can ignore compatible features, we can set them to 0 as well */ 4878 s->compatible_features = 0; 4879 /* if lazy refcounts have been used, they have already been fixed through 4880 * clearing the dirty flag */ 4881 4882 /* clearing autoclear features is trivial */ 4883 s->autoclear_features = 0; 4884 4885 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 4886 if (ret < 0) { 4887 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); 4888 return ret; 4889 } 4890 4891 s->qcow_version = target_version; 4892 ret = qcow2_update_header(bs); 4893 if (ret < 0) { 4894 s->qcow_version = current_version; 4895 error_setg_errno(errp, -ret, "Failed to update the image header"); 4896 return ret; 4897 } 4898 return 0; 4899 } 4900 4901 typedef enum Qcow2AmendOperation { 4902 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 4903 * statically initialized to so that the helper CB can discern the first 4904 * invocation from an operation change */ 4905 QCOW2_NO_OPERATION = 0, 4906 4907 QCOW2_CHANGING_REFCOUNT_ORDER, 4908 QCOW2_DOWNGRADING, 4909 } Qcow2AmendOperation; 4910 4911 typedef struct Qcow2AmendHelperCBInfo { 4912 /* The code coordinating the amend operations should only modify 4913 * these four fields; the rest will be managed by the CB */ 4914 BlockDriverAmendStatusCB *original_status_cb; 4915 void *original_cb_opaque; 4916 4917 Qcow2AmendOperation current_operation; 4918 4919 /* Total number of operations to perform (only set once) */ 4920 int total_operations; 4921 4922 /* The following fields are managed by the CB */ 4923 4924 /* Number of operations completed */ 4925 int operations_completed; 4926 4927 /* Cumulative offset of all completed operations */ 4928 int64_t offset_completed; 4929 4930 Qcow2AmendOperation last_operation; 4931 int64_t last_work_size; 4932 } Qcow2AmendHelperCBInfo; 4933 4934 static void qcow2_amend_helper_cb(BlockDriverState *bs, 4935 int64_t operation_offset, 4936 int64_t operation_work_size, void *opaque) 4937 { 4938 Qcow2AmendHelperCBInfo *info = opaque; 4939 int64_t current_work_size; 4940 int64_t projected_work_size; 4941 4942 if (info->current_operation != info->last_operation) { 4943 if (info->last_operation != QCOW2_NO_OPERATION) { 4944 info->offset_completed += info->last_work_size; 4945 info->operations_completed++; 4946 } 4947 4948 info->last_operation = info->current_operation; 4949 } 4950 4951 assert(info->total_operations > 0); 4952 assert(info->operations_completed < info->total_operations); 4953 4954 info->last_work_size = operation_work_size; 4955 4956 current_work_size = info->offset_completed + operation_work_size; 4957 4958 /* current_work_size is the total work size for (operations_completed + 1) 4959 * operations (which includes this one), so multiply it by the number of 4960 * operations not covered and divide it by the number of operations 4961 * covered to get a projection for the operations not covered */ 4962 projected_work_size = current_work_size * (info->total_operations - 4963 info->operations_completed - 1) 4964 / (info->operations_completed + 1); 4965 4966 info->original_status_cb(bs, info->offset_completed + operation_offset, 4967 current_work_size + projected_work_size, 4968 info->original_cb_opaque); 4969 } 4970 4971 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4972 BlockDriverAmendStatusCB *status_cb, 4973 void *cb_opaque, 4974 Error **errp) 4975 { 4976 BDRVQcow2State *s = bs->opaque; 4977 int old_version = s->qcow_version, new_version = old_version; 4978 uint64_t new_size = 0; 4979 const char *backing_file = NULL, *backing_format = NULL, *data_file = NULL; 4980 bool lazy_refcounts = s->use_lazy_refcounts; 4981 bool data_file_raw = data_file_is_raw(bs); 4982 const char *compat = NULL; 4983 uint64_t cluster_size = s->cluster_size; 4984 bool encrypt; 4985 int encformat; 4986 int refcount_bits = s->refcount_bits; 4987 int ret; 4988 QemuOptDesc *desc = opts->list->desc; 4989 Qcow2AmendHelperCBInfo helper_cb_info; 4990 4991 while (desc && desc->name) { 4992 if (!qemu_opt_find(opts, desc->name)) { 4993 /* only change explicitly defined options */ 4994 desc++; 4995 continue; 4996 } 4997 4998 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4999 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 5000 if (!compat) { 5001 /* preserve default */ 5002 } else if (!strcmp(compat, "0.10") || !strcmp(compat, "v2")) { 5003 new_version = 2; 5004 } else if (!strcmp(compat, "1.1") || !strcmp(compat, "v3")) { 5005 new_version = 3; 5006 } else { 5007 error_setg(errp, "Unknown compatibility level %s", compat); 5008 return -EINVAL; 5009 } 5010 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 5011 error_setg(errp, "Cannot change preallocation mode"); 5012 return -ENOTSUP; 5013 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 5014 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 5015 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 5016 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 5017 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 5018 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 5019 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 5020 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 5021 !!s->crypto); 5022 5023 if (encrypt != !!s->crypto) { 5024 error_setg(errp, 5025 "Changing the encryption flag is not supported"); 5026 return -ENOTSUP; 5027 } 5028 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 5029 encformat = qcow2_crypt_method_from_format( 5030 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 5031 5032 if (encformat != s->crypt_method_header) { 5033 error_setg(errp, 5034 "Changing the encryption format is not supported"); 5035 return -ENOTSUP; 5036 } 5037 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 5038 error_setg(errp, 5039 "Changing the encryption parameters is not supported"); 5040 return -ENOTSUP; 5041 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 5042 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 5043 cluster_size); 5044 if (cluster_size != s->cluster_size) { 5045 error_setg(errp, "Changing the cluster size is not supported"); 5046 return -ENOTSUP; 5047 } 5048 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 5049 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 5050 lazy_refcounts); 5051 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 5052 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 5053 refcount_bits); 5054 5055 if (refcount_bits <= 0 || refcount_bits > 64 || 5056 !is_power_of_2(refcount_bits)) 5057 { 5058 error_setg(errp, "Refcount width must be a power of two and " 5059 "may not exceed 64 bits"); 5060 return -EINVAL; 5061 } 5062 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) { 5063 data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE); 5064 if (data_file && !has_data_file(bs)) { 5065 error_setg(errp, "data-file can only be set for images that " 5066 "use an external data file"); 5067 return -EINVAL; 5068 } 5069 } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) { 5070 data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW, 5071 data_file_raw); 5072 if (data_file_raw && !data_file_is_raw(bs)) { 5073 error_setg(errp, "data-file-raw cannot be set on existing " 5074 "images"); 5075 return -EINVAL; 5076 } 5077 } else { 5078 /* if this point is reached, this probably means a new option was 5079 * added without having it covered here */ 5080 abort(); 5081 } 5082 5083 desc++; 5084 } 5085 5086 helper_cb_info = (Qcow2AmendHelperCBInfo){ 5087 .original_status_cb = status_cb, 5088 .original_cb_opaque = cb_opaque, 5089 .total_operations = (new_version < old_version) 5090 + (s->refcount_bits != refcount_bits) 5091 }; 5092 5093 /* Upgrade first (some features may require compat=1.1) */ 5094 if (new_version > old_version) { 5095 s->qcow_version = new_version; 5096 ret = qcow2_update_header(bs); 5097 if (ret < 0) { 5098 s->qcow_version = old_version; 5099 error_setg_errno(errp, -ret, "Failed to update the image header"); 5100 return ret; 5101 } 5102 } 5103 5104 if (s->refcount_bits != refcount_bits) { 5105 int refcount_order = ctz32(refcount_bits); 5106 5107 if (new_version < 3 && refcount_bits != 16) { 5108 error_setg(errp, "Refcount widths other than 16 bits require " 5109 "compatibility level 1.1 or above (use compat=1.1 or " 5110 "greater)"); 5111 return -EINVAL; 5112 } 5113 5114 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 5115 ret = qcow2_change_refcount_order(bs, refcount_order, 5116 &qcow2_amend_helper_cb, 5117 &helper_cb_info, errp); 5118 if (ret < 0) { 5119 return ret; 5120 } 5121 } 5122 5123 /* data-file-raw blocks backing files, so clear it first if requested */ 5124 if (data_file_raw) { 5125 s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW; 5126 } else { 5127 s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW; 5128 } 5129 5130 if (data_file) { 5131 g_free(s->image_data_file); 5132 s->image_data_file = *data_file ? g_strdup(data_file) : NULL; 5133 } 5134 5135 ret = qcow2_update_header(bs); 5136 if (ret < 0) { 5137 error_setg_errno(errp, -ret, "Failed to update the image header"); 5138 return ret; 5139 } 5140 5141 if (backing_file || backing_format) { 5142 ret = qcow2_change_backing_file(bs, 5143 backing_file ?: s->image_backing_file, 5144 backing_format ?: s->image_backing_format); 5145 if (ret < 0) { 5146 error_setg_errno(errp, -ret, "Failed to change the backing file"); 5147 return ret; 5148 } 5149 } 5150 5151 if (s->use_lazy_refcounts != lazy_refcounts) { 5152 if (lazy_refcounts) { 5153 if (new_version < 3) { 5154 error_setg(errp, "Lazy refcounts only supported with " 5155 "compatibility level 1.1 and above (use compat=1.1 " 5156 "or greater)"); 5157 return -EINVAL; 5158 } 5159 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 5160 ret = qcow2_update_header(bs); 5161 if (ret < 0) { 5162 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 5163 error_setg_errno(errp, -ret, "Failed to update the image header"); 5164 return ret; 5165 } 5166 s->use_lazy_refcounts = true; 5167 } else { 5168 /* make image clean first */ 5169 ret = qcow2_mark_clean(bs); 5170 if (ret < 0) { 5171 error_setg_errno(errp, -ret, "Failed to make the image clean"); 5172 return ret; 5173 } 5174 /* now disallow lazy refcounts */ 5175 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 5176 ret = qcow2_update_header(bs); 5177 if (ret < 0) { 5178 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 5179 error_setg_errno(errp, -ret, "Failed to update the image header"); 5180 return ret; 5181 } 5182 s->use_lazy_refcounts = false; 5183 } 5184 } 5185 5186 if (new_size) { 5187 BlockBackend *blk = blk_new(bdrv_get_aio_context(bs), 5188 BLK_PERM_RESIZE, BLK_PERM_ALL); 5189 ret = blk_insert_bs(blk, bs, errp); 5190 if (ret < 0) { 5191 blk_unref(blk); 5192 return ret; 5193 } 5194 5195 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp); 5196 blk_unref(blk); 5197 if (ret < 0) { 5198 return ret; 5199 } 5200 } 5201 5202 /* Downgrade last (so unsupported features can be removed before) */ 5203 if (new_version < old_version) { 5204 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 5205 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 5206 &helper_cb_info, errp); 5207 if (ret < 0) { 5208 return ret; 5209 } 5210 } 5211 5212 return 0; 5213 } 5214 5215 /* 5216 * If offset or size are negative, respectively, they will not be included in 5217 * the BLOCK_IMAGE_CORRUPTED event emitted. 5218 * fatal will be ignored for read-only BDS; corruptions found there will always 5219 * be considered non-fatal. 5220 */ 5221 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 5222 int64_t size, const char *message_format, ...) 5223 { 5224 BDRVQcow2State *s = bs->opaque; 5225 const char *node_name; 5226 char *message; 5227 va_list ap; 5228 5229 fatal = fatal && bdrv_is_writable(bs); 5230 5231 if (s->signaled_corruption && 5232 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 5233 { 5234 return; 5235 } 5236 5237 va_start(ap, message_format); 5238 message = g_strdup_vprintf(message_format, ap); 5239 va_end(ap); 5240 5241 if (fatal) { 5242 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 5243 "corruption events will be suppressed\n", message); 5244 } else { 5245 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 5246 "corruption events will be suppressed\n", message); 5247 } 5248 5249 node_name = bdrv_get_node_name(bs); 5250 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 5251 *node_name != '\0', node_name, 5252 message, offset >= 0, offset, 5253 size >= 0, size, 5254 fatal); 5255 g_free(message); 5256 5257 if (fatal) { 5258 qcow2_mark_corrupt(bs); 5259 bs->drv = NULL; /* make BDS unusable */ 5260 } 5261 5262 s->signaled_corruption = true; 5263 } 5264 5265 static QemuOptsList qcow2_create_opts = { 5266 .name = "qcow2-create-opts", 5267 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 5268 .desc = { 5269 { 5270 .name = BLOCK_OPT_SIZE, 5271 .type = QEMU_OPT_SIZE, 5272 .help = "Virtual disk size" 5273 }, 5274 { 5275 .name = BLOCK_OPT_COMPAT_LEVEL, 5276 .type = QEMU_OPT_STRING, 5277 .help = "Compatibility level (v2 [0.10] or v3 [1.1])" 5278 }, 5279 { 5280 .name = BLOCK_OPT_BACKING_FILE, 5281 .type = QEMU_OPT_STRING, 5282 .help = "File name of a base image" 5283 }, 5284 { 5285 .name = BLOCK_OPT_BACKING_FMT, 5286 .type = QEMU_OPT_STRING, 5287 .help = "Image format of the base image" 5288 }, 5289 { 5290 .name = BLOCK_OPT_DATA_FILE, 5291 .type = QEMU_OPT_STRING, 5292 .help = "File name of an external data file" 5293 }, 5294 { 5295 .name = BLOCK_OPT_DATA_FILE_RAW, 5296 .type = QEMU_OPT_BOOL, 5297 .help = "The external data file must stay valid as a raw image" 5298 }, 5299 { 5300 .name = BLOCK_OPT_ENCRYPT, 5301 .type = QEMU_OPT_BOOL, 5302 .help = "Encrypt the image with format 'aes'. (Deprecated " 5303 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 5304 }, 5305 { 5306 .name = BLOCK_OPT_ENCRYPT_FORMAT, 5307 .type = QEMU_OPT_STRING, 5308 .help = "Encrypt the image, format choices: 'aes', 'luks'", 5309 }, 5310 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 5311 "ID of secret providing qcow AES key or LUKS passphrase"), 5312 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 5313 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 5314 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 5315 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 5316 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 5317 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 5318 { 5319 .name = BLOCK_OPT_CLUSTER_SIZE, 5320 .type = QEMU_OPT_SIZE, 5321 .help = "qcow2 cluster size", 5322 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 5323 }, 5324 { 5325 .name = BLOCK_OPT_PREALLOC, 5326 .type = QEMU_OPT_STRING, 5327 .help = "Preallocation mode (allowed values: off, metadata, " 5328 "falloc, full)" 5329 }, 5330 { 5331 .name = BLOCK_OPT_LAZY_REFCOUNTS, 5332 .type = QEMU_OPT_BOOL, 5333 .help = "Postpone refcount updates", 5334 .def_value_str = "off" 5335 }, 5336 { 5337 .name = BLOCK_OPT_REFCOUNT_BITS, 5338 .type = QEMU_OPT_NUMBER, 5339 .help = "Width of a reference count entry in bits", 5340 .def_value_str = "16" 5341 }, 5342 { /* end of list */ } 5343 } 5344 }; 5345 5346 static const char *const qcow2_strong_runtime_opts[] = { 5347 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 5348 5349 NULL 5350 }; 5351 5352 BlockDriver bdrv_qcow2 = { 5353 .format_name = "qcow2", 5354 .instance_size = sizeof(BDRVQcow2State), 5355 .bdrv_probe = qcow2_probe, 5356 .bdrv_open = qcow2_open, 5357 .bdrv_close = qcow2_close, 5358 .bdrv_reopen_prepare = qcow2_reopen_prepare, 5359 .bdrv_reopen_commit = qcow2_reopen_commit, 5360 .bdrv_reopen_abort = qcow2_reopen_abort, 5361 .bdrv_join_options = qcow2_join_options, 5362 .bdrv_child_perm = bdrv_format_default_perms, 5363 .bdrv_co_create_opts = qcow2_co_create_opts, 5364 .bdrv_co_create = qcow2_co_create, 5365 .bdrv_has_zero_init = qcow2_has_zero_init, 5366 .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1, 5367 .bdrv_co_block_status = qcow2_co_block_status, 5368 5369 .bdrv_co_preadv_part = qcow2_co_preadv_part, 5370 .bdrv_co_pwritev_part = qcow2_co_pwritev_part, 5371 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 5372 5373 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 5374 .bdrv_co_pdiscard = qcow2_co_pdiscard, 5375 .bdrv_co_copy_range_from = qcow2_co_copy_range_from, 5376 .bdrv_co_copy_range_to = qcow2_co_copy_range_to, 5377 .bdrv_co_truncate = qcow2_co_truncate, 5378 .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part, 5379 .bdrv_make_empty = qcow2_make_empty, 5380 5381 .bdrv_snapshot_create = qcow2_snapshot_create, 5382 .bdrv_snapshot_goto = qcow2_snapshot_goto, 5383 .bdrv_snapshot_delete = qcow2_snapshot_delete, 5384 .bdrv_snapshot_list = qcow2_snapshot_list, 5385 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 5386 .bdrv_measure = qcow2_measure, 5387 .bdrv_get_info = qcow2_get_info, 5388 .bdrv_get_specific_info = qcow2_get_specific_info, 5389 5390 .bdrv_save_vmstate = qcow2_save_vmstate, 5391 .bdrv_load_vmstate = qcow2_load_vmstate, 5392 5393 .supports_backing = true, 5394 .bdrv_change_backing_file = qcow2_change_backing_file, 5395 5396 .bdrv_refresh_limits = qcow2_refresh_limits, 5397 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, 5398 .bdrv_inactivate = qcow2_inactivate, 5399 5400 .create_opts = &qcow2_create_opts, 5401 .strong_runtime_opts = qcow2_strong_runtime_opts, 5402 .mutable_opts = mutable_opts, 5403 .bdrv_co_check = qcow2_co_check, 5404 .bdrv_amend_options = qcow2_amend_options, 5405 5406 .bdrv_detach_aio_context = qcow2_detach_aio_context, 5407 .bdrv_attach_aio_context = qcow2_attach_aio_context, 5408 5409 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 5410 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 5411 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 5412 }; 5413 5414 static void bdrv_qcow2_init(void) 5415 { 5416 bdrv_register(&bdrv_qcow2); 5417 } 5418 5419 block_init(bdrv_qcow2_init); 5420