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 #define ZLIB_CONST 28 #include <zlib.h> 29 30 #include "block/block_int.h" 31 #include "block/qdict.h" 32 #include "sysemu/block-backend.h" 33 #include "qemu/module.h" 34 #include "qcow2.h" 35 #include "qemu/error-report.h" 36 #include "qapi/error.h" 37 #include "qapi/qapi-events-block-core.h" 38 #include "qapi/qmp/qdict.h" 39 #include "qapi/qmp/qstring.h" 40 #include "trace.h" 41 #include "qemu/option_int.h" 42 #include "qemu/cutils.h" 43 #include "qemu/bswap.h" 44 #include "qapi/qobject-input-visitor.h" 45 #include "qapi/qapi-visit-block-core.h" 46 #include "crypto.h" 47 #include "block/thread-pool.h" 48 49 /* 50 Differences with QCOW: 51 52 - Support for multiple incremental snapshots. 53 - Memory management by reference counts. 54 - Clusters which have a reference count of one have the bit 55 QCOW_OFLAG_COPIED to optimize write performance. 56 - Size of compressed clusters is stored in sectors to reduce bit usage 57 in the cluster offsets. 58 - Support for storing additional data (such as the VM state) in the 59 snapshots. 60 - If a backing store is used, the cluster size is not constrained 61 (could be backported to QCOW). 62 - L2 tables have always a size of one cluster. 63 */ 64 65 66 typedef struct { 67 uint32_t magic; 68 uint32_t len; 69 } QEMU_PACKED QCowExtension; 70 71 #define QCOW2_EXT_MAGIC_END 0 72 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 73 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 74 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 75 #define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 76 77 static int coroutine_fn 78 qcow2_co_preadv_compressed(BlockDriverState *bs, 79 uint64_t file_cluster_offset, 80 uint64_t offset, 81 uint64_t bytes, 82 QEMUIOVector *qiov); 83 84 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 85 { 86 const QCowHeader *cow_header = (const void *)buf; 87 88 if (buf_size >= sizeof(QCowHeader) && 89 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 90 be32_to_cpu(cow_header->version) >= 2) 91 return 100; 92 else 93 return 0; 94 } 95 96 97 static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, 98 uint8_t *buf, size_t buflen, 99 void *opaque, Error **errp) 100 { 101 BlockDriverState *bs = opaque; 102 BDRVQcow2State *s = bs->opaque; 103 ssize_t ret; 104 105 if ((offset + buflen) > s->crypto_header.length) { 106 error_setg(errp, "Request for data outside of extension header"); 107 return -1; 108 } 109 110 ret = bdrv_pread(bs->file, 111 s->crypto_header.offset + offset, buf, buflen); 112 if (ret < 0) { 113 error_setg_errno(errp, -ret, "Could not read encryption header"); 114 return -1; 115 } 116 return ret; 117 } 118 119 120 static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, 121 void *opaque, Error **errp) 122 { 123 BlockDriverState *bs = opaque; 124 BDRVQcow2State *s = bs->opaque; 125 int64_t ret; 126 int64_t clusterlen; 127 128 ret = qcow2_alloc_clusters(bs, headerlen); 129 if (ret < 0) { 130 error_setg_errno(errp, -ret, 131 "Cannot allocate cluster for LUKS header size %zu", 132 headerlen); 133 return -1; 134 } 135 136 s->crypto_header.length = headerlen; 137 s->crypto_header.offset = ret; 138 139 /* Zero fill remaining space in cluster so it has predictable 140 * content in case of future spec changes */ 141 clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; 142 assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen) == 0); 143 ret = bdrv_pwrite_zeroes(bs->file, 144 ret + headerlen, 145 clusterlen - headerlen, 0); 146 if (ret < 0) { 147 error_setg_errno(errp, -ret, "Could not zero fill encryption header"); 148 return -1; 149 } 150 151 return ret; 152 } 153 154 155 static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, 156 const uint8_t *buf, size_t buflen, 157 void *opaque, Error **errp) 158 { 159 BlockDriverState *bs = opaque; 160 BDRVQcow2State *s = bs->opaque; 161 ssize_t ret; 162 163 if ((offset + buflen) > s->crypto_header.length) { 164 error_setg(errp, "Request for data outside of extension header"); 165 return -1; 166 } 167 168 ret = bdrv_pwrite(bs->file, 169 s->crypto_header.offset + offset, buf, buflen); 170 if (ret < 0) { 171 error_setg_errno(errp, -ret, "Could not read encryption header"); 172 return -1; 173 } 174 return ret; 175 } 176 177 178 /* 179 * read qcow2 extension and fill bs 180 * start reading from start_offset 181 * finish reading upon magic of value 0 or when end_offset reached 182 * unknown magic is skipped (future extension this version knows nothing about) 183 * return 0 upon success, non-0 otherwise 184 */ 185 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 186 uint64_t end_offset, void **p_feature_table, 187 int flags, bool *need_update_header, 188 Error **errp) 189 { 190 BDRVQcow2State *s = bs->opaque; 191 QCowExtension ext; 192 uint64_t offset; 193 int ret; 194 Qcow2BitmapHeaderExt bitmaps_ext; 195 196 if (need_update_header != NULL) { 197 *need_update_header = false; 198 } 199 200 #ifdef DEBUG_EXT 201 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 202 #endif 203 offset = start_offset; 204 while (offset < end_offset) { 205 206 #ifdef DEBUG_EXT 207 /* Sanity check */ 208 if (offset > s->cluster_size) 209 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 210 211 printf("attempting to read extended header in offset %lu\n", offset); 212 #endif 213 214 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 215 if (ret < 0) { 216 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 217 "pread fail from offset %" PRIu64, offset); 218 return 1; 219 } 220 ext.magic = be32_to_cpu(ext.magic); 221 ext.len = be32_to_cpu(ext.len); 222 offset += sizeof(ext); 223 #ifdef DEBUG_EXT 224 printf("ext.magic = 0x%x\n", ext.magic); 225 #endif 226 if (offset > end_offset || ext.len > end_offset - offset) { 227 error_setg(errp, "Header extension too large"); 228 return -EINVAL; 229 } 230 231 switch (ext.magic) { 232 case QCOW2_EXT_MAGIC_END: 233 return 0; 234 235 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 236 if (ext.len >= sizeof(bs->backing_format)) { 237 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 238 " too large (>=%zu)", ext.len, 239 sizeof(bs->backing_format)); 240 return 2; 241 } 242 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 243 if (ret < 0) { 244 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 245 "Could not read format name"); 246 return 3; 247 } 248 bs->backing_format[ext.len] = '\0'; 249 s->image_backing_format = g_strdup(bs->backing_format); 250 #ifdef DEBUG_EXT 251 printf("Qcow2: Got format extension %s\n", bs->backing_format); 252 #endif 253 break; 254 255 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 256 if (p_feature_table != NULL) { 257 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 258 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 259 if (ret < 0) { 260 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 261 "Could not read table"); 262 return ret; 263 } 264 265 *p_feature_table = feature_table; 266 } 267 break; 268 269 case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { 270 unsigned int cflags = 0; 271 if (s->crypt_method_header != QCOW_CRYPT_LUKS) { 272 error_setg(errp, "CRYPTO header extension only " 273 "expected with LUKS encryption method"); 274 return -EINVAL; 275 } 276 if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { 277 error_setg(errp, "CRYPTO header extension size %u, " 278 "but expected size %zu", ext.len, 279 sizeof(Qcow2CryptoHeaderExtension)); 280 return -EINVAL; 281 } 282 283 ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); 284 if (ret < 0) { 285 error_setg_errno(errp, -ret, 286 "Unable to read CRYPTO header extension"); 287 return ret; 288 } 289 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 290 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 291 292 if ((s->crypto_header.offset % s->cluster_size) != 0) { 293 error_setg(errp, "Encryption header offset '%" PRIu64 "' is " 294 "not a multiple of cluster size '%u'", 295 s->crypto_header.offset, s->cluster_size); 296 return -EINVAL; 297 } 298 299 if (flags & BDRV_O_NO_IO) { 300 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 301 } 302 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 303 qcow2_crypto_hdr_read_func, 304 bs, cflags, 1, errp); 305 if (!s->crypto) { 306 return -EINVAL; 307 } 308 } break; 309 310 case QCOW2_EXT_MAGIC_BITMAPS: 311 if (ext.len != sizeof(bitmaps_ext)) { 312 error_setg_errno(errp, -ret, "bitmaps_ext: " 313 "Invalid extension length"); 314 return -EINVAL; 315 } 316 317 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { 318 if (s->qcow_version < 3) { 319 /* Let's be a bit more specific */ 320 warn_report("This qcow2 v2 image contains bitmaps, but " 321 "they may have been modified by a program " 322 "without persistent bitmap support; so now " 323 "they must all be considered inconsistent"); 324 } else { 325 warn_report("a program lacking bitmap support " 326 "modified this file, so all bitmaps are now " 327 "considered inconsistent"); 328 } 329 error_printf("Some clusters may be leaked, " 330 "run 'qemu-img check -r' on the image " 331 "file to fix."); 332 if (need_update_header != NULL) { 333 /* Updating is needed to drop invalid bitmap extension. */ 334 *need_update_header = true; 335 } 336 break; 337 } 338 339 ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); 340 if (ret < 0) { 341 error_setg_errno(errp, -ret, "bitmaps_ext: " 342 "Could not read ext header"); 343 return ret; 344 } 345 346 if (bitmaps_ext.reserved32 != 0) { 347 error_setg_errno(errp, -ret, "bitmaps_ext: " 348 "Reserved field is not zero"); 349 return -EINVAL; 350 } 351 352 bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps); 353 bitmaps_ext.bitmap_directory_size = 354 be64_to_cpu(bitmaps_ext.bitmap_directory_size); 355 bitmaps_ext.bitmap_directory_offset = 356 be64_to_cpu(bitmaps_ext.bitmap_directory_offset); 357 358 if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { 359 error_setg(errp, 360 "bitmaps_ext: Image has %" PRIu32 " bitmaps, " 361 "exceeding the QEMU supported maximum of %d", 362 bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); 363 return -EINVAL; 364 } 365 366 if (bitmaps_ext.nb_bitmaps == 0) { 367 error_setg(errp, "found bitmaps extension with zero bitmaps"); 368 return -EINVAL; 369 } 370 371 if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { 372 error_setg(errp, "bitmaps_ext: " 373 "invalid bitmap directory offset"); 374 return -EINVAL; 375 } 376 377 if (bitmaps_ext.bitmap_directory_size > 378 QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { 379 error_setg(errp, "bitmaps_ext: " 380 "bitmap directory size (%" PRIu64 ") exceeds " 381 "the maximum supported size (%d)", 382 bitmaps_ext.bitmap_directory_size, 383 QCOW2_MAX_BITMAP_DIRECTORY_SIZE); 384 return -EINVAL; 385 } 386 387 s->nb_bitmaps = bitmaps_ext.nb_bitmaps; 388 s->bitmap_directory_offset = 389 bitmaps_ext.bitmap_directory_offset; 390 s->bitmap_directory_size = 391 bitmaps_ext.bitmap_directory_size; 392 393 #ifdef DEBUG_EXT 394 printf("Qcow2: Got bitmaps extension: " 395 "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", 396 s->bitmap_directory_offset, s->nb_bitmaps); 397 #endif 398 break; 399 400 default: 401 /* unknown magic - save it in case we need to rewrite the header */ 402 /* If you add a new feature, make sure to also update the fast 403 * path of qcow2_make_empty() to deal with it. */ 404 { 405 Qcow2UnknownHeaderExtension *uext; 406 407 uext = g_malloc0(sizeof(*uext) + ext.len); 408 uext->magic = ext.magic; 409 uext->len = ext.len; 410 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 411 412 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 413 if (ret < 0) { 414 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 415 "Could not read data"); 416 return ret; 417 } 418 } 419 break; 420 } 421 422 offset += ((ext.len + 7) & ~7); 423 } 424 425 return 0; 426 } 427 428 static void cleanup_unknown_header_ext(BlockDriverState *bs) 429 { 430 BDRVQcow2State *s = bs->opaque; 431 Qcow2UnknownHeaderExtension *uext, *next; 432 433 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 434 QLIST_REMOVE(uext, next); 435 g_free(uext); 436 } 437 } 438 439 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 440 uint64_t mask) 441 { 442 char *features = g_strdup(""); 443 char *old; 444 445 while (table && table->name[0] != '\0') { 446 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 447 if (mask & (1ULL << table->bit)) { 448 old = features; 449 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 450 table->name); 451 g_free(old); 452 mask &= ~(1ULL << table->bit); 453 } 454 } 455 table++; 456 } 457 458 if (mask) { 459 old = features; 460 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 461 old, *old ? ", " : "", mask); 462 g_free(old); 463 } 464 465 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 466 g_free(features); 467 } 468 469 /* 470 * Sets the dirty bit and flushes afterwards if necessary. 471 * 472 * The incompatible_features bit is only set if the image file header was 473 * updated successfully. Therefore it is not required to check the return 474 * value of this function. 475 */ 476 int qcow2_mark_dirty(BlockDriverState *bs) 477 { 478 BDRVQcow2State *s = bs->opaque; 479 uint64_t val; 480 int ret; 481 482 assert(s->qcow_version >= 3); 483 484 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 485 return 0; /* already dirty */ 486 } 487 488 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 489 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 490 &val, sizeof(val)); 491 if (ret < 0) { 492 return ret; 493 } 494 ret = bdrv_flush(bs->file->bs); 495 if (ret < 0) { 496 return ret; 497 } 498 499 /* Only treat image as dirty if the header was updated successfully */ 500 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 501 return 0; 502 } 503 504 /* 505 * Clears the dirty bit and flushes before if necessary. Only call this 506 * function when there are no pending requests, it does not guard against 507 * concurrent requests dirtying the image. 508 */ 509 static int qcow2_mark_clean(BlockDriverState *bs) 510 { 511 BDRVQcow2State *s = bs->opaque; 512 513 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 514 int ret; 515 516 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 517 518 ret = qcow2_flush_caches(bs); 519 if (ret < 0) { 520 return ret; 521 } 522 523 return qcow2_update_header(bs); 524 } 525 return 0; 526 } 527 528 /* 529 * Marks the image as corrupt. 530 */ 531 int qcow2_mark_corrupt(BlockDriverState *bs) 532 { 533 BDRVQcow2State *s = bs->opaque; 534 535 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 536 return qcow2_update_header(bs); 537 } 538 539 /* 540 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 541 * before if necessary. 542 */ 543 int qcow2_mark_consistent(BlockDriverState *bs) 544 { 545 BDRVQcow2State *s = bs->opaque; 546 547 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 548 int ret = qcow2_flush_caches(bs); 549 if (ret < 0) { 550 return ret; 551 } 552 553 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 554 return qcow2_update_header(bs); 555 } 556 return 0; 557 } 558 559 static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, 560 BdrvCheckResult *result, 561 BdrvCheckMode fix) 562 { 563 int ret = qcow2_check_refcounts(bs, result, fix); 564 if (ret < 0) { 565 return ret; 566 } 567 568 if (fix && result->check_errors == 0 && result->corruptions == 0) { 569 ret = qcow2_mark_clean(bs); 570 if (ret < 0) { 571 return ret; 572 } 573 return qcow2_mark_consistent(bs); 574 } 575 return ret; 576 } 577 578 static int coroutine_fn qcow2_co_check(BlockDriverState *bs, 579 BdrvCheckResult *result, 580 BdrvCheckMode fix) 581 { 582 BDRVQcow2State *s = bs->opaque; 583 int ret; 584 585 qemu_co_mutex_lock(&s->lock); 586 ret = qcow2_co_check_locked(bs, result, fix); 587 qemu_co_mutex_unlock(&s->lock); 588 return ret; 589 } 590 591 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, 592 uint64_t entries, size_t entry_len, 593 int64_t max_size_bytes, const char *table_name, 594 Error **errp) 595 { 596 BDRVQcow2State *s = bs->opaque; 597 598 if (entries > max_size_bytes / entry_len) { 599 error_setg(errp, "%s too large", table_name); 600 return -EFBIG; 601 } 602 603 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 604 * because values will be passed to qemu functions taking int64_t. */ 605 if ((INT64_MAX - entries * entry_len < offset) || 606 (offset_into_cluster(s, offset) != 0)) { 607 error_setg(errp, "%s offset invalid", table_name); 608 return -EINVAL; 609 } 610 611 return 0; 612 } 613 614 static QemuOptsList qcow2_runtime_opts = { 615 .name = "qcow2", 616 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 617 .desc = { 618 { 619 .name = QCOW2_OPT_LAZY_REFCOUNTS, 620 .type = QEMU_OPT_BOOL, 621 .help = "Postpone refcount updates", 622 }, 623 { 624 .name = QCOW2_OPT_DISCARD_REQUEST, 625 .type = QEMU_OPT_BOOL, 626 .help = "Pass guest discard requests to the layer below", 627 }, 628 { 629 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 630 .type = QEMU_OPT_BOOL, 631 .help = "Generate discard requests when snapshot related space " 632 "is freed", 633 }, 634 { 635 .name = QCOW2_OPT_DISCARD_OTHER, 636 .type = QEMU_OPT_BOOL, 637 .help = "Generate discard requests when other clusters are freed", 638 }, 639 { 640 .name = QCOW2_OPT_OVERLAP, 641 .type = QEMU_OPT_STRING, 642 .help = "Selects which overlap checks to perform from a range of " 643 "templates (none, constant, cached, all)", 644 }, 645 { 646 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 647 .type = QEMU_OPT_STRING, 648 .help = "Selects which overlap checks to perform from a range of " 649 "templates (none, constant, cached, all)", 650 }, 651 { 652 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 653 .type = QEMU_OPT_BOOL, 654 .help = "Check for unintended writes into the main qcow2 header", 655 }, 656 { 657 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 658 .type = QEMU_OPT_BOOL, 659 .help = "Check for unintended writes into the active L1 table", 660 }, 661 { 662 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 663 .type = QEMU_OPT_BOOL, 664 .help = "Check for unintended writes into an active L2 table", 665 }, 666 { 667 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 668 .type = QEMU_OPT_BOOL, 669 .help = "Check for unintended writes into the refcount table", 670 }, 671 { 672 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 673 .type = QEMU_OPT_BOOL, 674 .help = "Check for unintended writes into a refcount block", 675 }, 676 { 677 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 678 .type = QEMU_OPT_BOOL, 679 .help = "Check for unintended writes into the snapshot table", 680 }, 681 { 682 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 683 .type = QEMU_OPT_BOOL, 684 .help = "Check for unintended writes into an inactive L1 table", 685 }, 686 { 687 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 688 .type = QEMU_OPT_BOOL, 689 .help = "Check for unintended writes into an inactive L2 table", 690 }, 691 { 692 .name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 693 .type = QEMU_OPT_BOOL, 694 .help = "Check for unintended writes into the bitmap directory", 695 }, 696 { 697 .name = QCOW2_OPT_CACHE_SIZE, 698 .type = QEMU_OPT_SIZE, 699 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 700 "cache size", 701 }, 702 { 703 .name = QCOW2_OPT_L2_CACHE_SIZE, 704 .type = QEMU_OPT_SIZE, 705 .help = "Maximum L2 table cache size", 706 }, 707 { 708 .name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE, 709 .type = QEMU_OPT_SIZE, 710 .help = "Size of each entry in the L2 cache", 711 }, 712 { 713 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 714 .type = QEMU_OPT_SIZE, 715 .help = "Maximum refcount block cache size", 716 }, 717 { 718 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 719 .type = QEMU_OPT_NUMBER, 720 .help = "Clean unused cache entries after this time (in seconds)", 721 }, 722 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 723 "ID of secret providing qcow2 AES key or LUKS passphrase"), 724 { /* end of list */ } 725 }, 726 }; 727 728 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 729 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 730 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 731 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 732 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 733 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 734 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 735 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 736 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 737 [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, 738 }; 739 740 static void cache_clean_timer_cb(void *opaque) 741 { 742 BlockDriverState *bs = opaque; 743 BDRVQcow2State *s = bs->opaque; 744 qcow2_cache_clean_unused(s->l2_table_cache); 745 qcow2_cache_clean_unused(s->refcount_block_cache); 746 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 747 (int64_t) s->cache_clean_interval * 1000); 748 } 749 750 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 751 { 752 BDRVQcow2State *s = bs->opaque; 753 if (s->cache_clean_interval > 0) { 754 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 755 SCALE_MS, cache_clean_timer_cb, 756 bs); 757 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 758 (int64_t) s->cache_clean_interval * 1000); 759 } 760 } 761 762 static void cache_clean_timer_del(BlockDriverState *bs) 763 { 764 BDRVQcow2State *s = bs->opaque; 765 if (s->cache_clean_timer) { 766 timer_del(s->cache_clean_timer); 767 timer_free(s->cache_clean_timer); 768 s->cache_clean_timer = NULL; 769 } 770 } 771 772 static void qcow2_detach_aio_context(BlockDriverState *bs) 773 { 774 cache_clean_timer_del(bs); 775 } 776 777 static void qcow2_attach_aio_context(BlockDriverState *bs, 778 AioContext *new_context) 779 { 780 cache_clean_timer_init(bs, new_context); 781 } 782 783 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 784 uint64_t *l2_cache_size, 785 uint64_t *l2_cache_entry_size, 786 uint64_t *refcount_cache_size, Error **errp) 787 { 788 BDRVQcow2State *s = bs->opaque; 789 uint64_t combined_cache_size, l2_cache_max_setting; 790 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 791 int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; 792 uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; 793 uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8); 794 795 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 796 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 797 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 798 799 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 800 l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 801 DEFAULT_L2_CACHE_MAX_SIZE); 802 *refcount_cache_size = qemu_opt_get_size(opts, 803 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 804 805 *l2_cache_entry_size = qemu_opt_get_size( 806 opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); 807 808 *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting); 809 810 if (combined_cache_size_set) { 811 if (l2_cache_size_set && refcount_cache_size_set) { 812 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 813 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 814 "at the same time"); 815 return; 816 } else if (l2_cache_size_set && 817 (l2_cache_max_setting > combined_cache_size)) { 818 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 819 QCOW2_OPT_CACHE_SIZE); 820 return; 821 } else if (*refcount_cache_size > combined_cache_size) { 822 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 823 QCOW2_OPT_CACHE_SIZE); 824 return; 825 } 826 827 if (l2_cache_size_set) { 828 *refcount_cache_size = combined_cache_size - *l2_cache_size; 829 } else if (refcount_cache_size_set) { 830 *l2_cache_size = combined_cache_size - *refcount_cache_size; 831 } else { 832 /* Assign as much memory as possible to the L2 cache, and 833 * use the remainder for the refcount cache */ 834 if (combined_cache_size >= max_l2_cache + min_refcount_cache) { 835 *l2_cache_size = max_l2_cache; 836 *refcount_cache_size = combined_cache_size - *l2_cache_size; 837 } else { 838 *refcount_cache_size = 839 MIN(combined_cache_size, min_refcount_cache); 840 *l2_cache_size = combined_cache_size - *refcount_cache_size; 841 } 842 } 843 } 844 /* l2_cache_size and refcount_cache_size are ensured to have at least 845 * their minimum values in qcow2_update_options_prepare() */ 846 847 if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || 848 *l2_cache_entry_size > s->cluster_size || 849 !is_power_of_2(*l2_cache_entry_size)) { 850 error_setg(errp, "L2 cache entry size must be a power of two " 851 "between %d and the cluster size (%d)", 852 1 << MIN_CLUSTER_BITS, s->cluster_size); 853 return; 854 } 855 } 856 857 typedef struct Qcow2ReopenState { 858 Qcow2Cache *l2_table_cache; 859 Qcow2Cache *refcount_block_cache; 860 int l2_slice_size; /* Number of entries in a slice of the L2 table */ 861 bool use_lazy_refcounts; 862 int overlap_check; 863 bool discard_passthrough[QCOW2_DISCARD_MAX]; 864 uint64_t cache_clean_interval; 865 QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ 866 } Qcow2ReopenState; 867 868 static int qcow2_update_options_prepare(BlockDriverState *bs, 869 Qcow2ReopenState *r, 870 QDict *options, int flags, 871 Error **errp) 872 { 873 BDRVQcow2State *s = bs->opaque; 874 QemuOpts *opts = NULL; 875 const char *opt_overlap_check, *opt_overlap_check_template; 876 int overlap_check_template = 0; 877 uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size; 878 int i; 879 const char *encryptfmt; 880 QDict *encryptopts = NULL; 881 Error *local_err = NULL; 882 int ret; 883 884 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 885 encryptfmt = qdict_get_try_str(encryptopts, "format"); 886 887 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 888 qemu_opts_absorb_qdict(opts, options, &local_err); 889 if (local_err) { 890 error_propagate(errp, local_err); 891 ret = -EINVAL; 892 goto fail; 893 } 894 895 /* get L2 table/refcount block cache size from command line options */ 896 read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, 897 &refcount_cache_size, &local_err); 898 if (local_err) { 899 error_propagate(errp, local_err); 900 ret = -EINVAL; 901 goto fail; 902 } 903 904 l2_cache_size /= l2_cache_entry_size; 905 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 906 l2_cache_size = MIN_L2_CACHE_SIZE; 907 } 908 if (l2_cache_size > INT_MAX) { 909 error_setg(errp, "L2 cache size too big"); 910 ret = -EINVAL; 911 goto fail; 912 } 913 914 refcount_cache_size /= s->cluster_size; 915 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 916 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 917 } 918 if (refcount_cache_size > INT_MAX) { 919 error_setg(errp, "Refcount cache size too big"); 920 ret = -EINVAL; 921 goto fail; 922 } 923 924 /* alloc new L2 table/refcount block cache, flush old one */ 925 if (s->l2_table_cache) { 926 ret = qcow2_cache_flush(bs, s->l2_table_cache); 927 if (ret) { 928 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 929 goto fail; 930 } 931 } 932 933 if (s->refcount_block_cache) { 934 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 935 if (ret) { 936 error_setg_errno(errp, -ret, 937 "Failed to flush the refcount block cache"); 938 goto fail; 939 } 940 } 941 942 r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t); 943 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, 944 l2_cache_entry_size); 945 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, 946 s->cluster_size); 947 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 948 error_setg(errp, "Could not allocate metadata caches"); 949 ret = -ENOMEM; 950 goto fail; 951 } 952 953 /* New interval for cache cleanup timer */ 954 r->cache_clean_interval = 955 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 956 DEFAULT_CACHE_CLEAN_INTERVAL); 957 #ifndef CONFIG_LINUX 958 if (r->cache_clean_interval != 0) { 959 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 960 " not supported on this host"); 961 ret = -EINVAL; 962 goto fail; 963 } 964 #endif 965 if (r->cache_clean_interval > UINT_MAX) { 966 error_setg(errp, "Cache clean interval too big"); 967 ret = -EINVAL; 968 goto fail; 969 } 970 971 /* lazy-refcounts; flush if going from enabled to disabled */ 972 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 973 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 974 if (r->use_lazy_refcounts && s->qcow_version < 3) { 975 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 976 "qemu 1.1 compatibility level"); 977 ret = -EINVAL; 978 goto fail; 979 } 980 981 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 982 ret = qcow2_mark_clean(bs); 983 if (ret < 0) { 984 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 985 goto fail; 986 } 987 } 988 989 /* Overlap check options */ 990 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 991 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 992 if (opt_overlap_check_template && opt_overlap_check && 993 strcmp(opt_overlap_check_template, opt_overlap_check)) 994 { 995 error_setg(errp, "Conflicting values for qcow2 options '" 996 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 997 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 998 ret = -EINVAL; 999 goto fail; 1000 } 1001 if (!opt_overlap_check) { 1002 opt_overlap_check = opt_overlap_check_template ?: "cached"; 1003 } 1004 1005 if (!strcmp(opt_overlap_check, "none")) { 1006 overlap_check_template = 0; 1007 } else if (!strcmp(opt_overlap_check, "constant")) { 1008 overlap_check_template = QCOW2_OL_CONSTANT; 1009 } else if (!strcmp(opt_overlap_check, "cached")) { 1010 overlap_check_template = QCOW2_OL_CACHED; 1011 } else if (!strcmp(opt_overlap_check, "all")) { 1012 overlap_check_template = QCOW2_OL_ALL; 1013 } else { 1014 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1015 "'overlap-check'. Allowed are any of the following: " 1016 "none, constant, cached, all", opt_overlap_check); 1017 ret = -EINVAL; 1018 goto fail; 1019 } 1020 1021 r->overlap_check = 0; 1022 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1023 /* overlap-check defines a template bitmask, but every flag may be 1024 * overwritten through the associated boolean option */ 1025 r->overlap_check |= 1026 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1027 overlap_check_template & (1 << i)) << i; 1028 } 1029 1030 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 1031 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1032 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1033 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1034 flags & BDRV_O_UNMAP); 1035 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1036 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1037 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 1038 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1039 1040 switch (s->crypt_method_header) { 1041 case QCOW_CRYPT_NONE: 1042 if (encryptfmt) { 1043 error_setg(errp, "No encryption in image header, but options " 1044 "specified format '%s'", encryptfmt); 1045 ret = -EINVAL; 1046 goto fail; 1047 } 1048 break; 1049 1050 case QCOW_CRYPT_AES: 1051 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 1052 error_setg(errp, 1053 "Header reported 'aes' encryption format but " 1054 "options specify '%s'", encryptfmt); 1055 ret = -EINVAL; 1056 goto fail; 1057 } 1058 qdict_put_str(encryptopts, "format", "qcow"); 1059 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1060 break; 1061 1062 case QCOW_CRYPT_LUKS: 1063 if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { 1064 error_setg(errp, 1065 "Header reported 'luks' encryption format but " 1066 "options specify '%s'", encryptfmt); 1067 ret = -EINVAL; 1068 goto fail; 1069 } 1070 qdict_put_str(encryptopts, "format", "luks"); 1071 r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 1072 break; 1073 1074 default: 1075 error_setg(errp, "Unsupported encryption method %d", 1076 s->crypt_method_header); 1077 break; 1078 } 1079 if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { 1080 ret = -EINVAL; 1081 goto fail; 1082 } 1083 1084 ret = 0; 1085 fail: 1086 qobject_unref(encryptopts); 1087 qemu_opts_del(opts); 1088 opts = NULL; 1089 return ret; 1090 } 1091 1092 static void qcow2_update_options_commit(BlockDriverState *bs, 1093 Qcow2ReopenState *r) 1094 { 1095 BDRVQcow2State *s = bs->opaque; 1096 int i; 1097 1098 if (s->l2_table_cache) { 1099 qcow2_cache_destroy(s->l2_table_cache); 1100 } 1101 if (s->refcount_block_cache) { 1102 qcow2_cache_destroy(s->refcount_block_cache); 1103 } 1104 s->l2_table_cache = r->l2_table_cache; 1105 s->refcount_block_cache = r->refcount_block_cache; 1106 s->l2_slice_size = r->l2_slice_size; 1107 1108 s->overlap_check = r->overlap_check; 1109 s->use_lazy_refcounts = r->use_lazy_refcounts; 1110 1111 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 1112 s->discard_passthrough[i] = r->discard_passthrough[i]; 1113 } 1114 1115 if (s->cache_clean_interval != r->cache_clean_interval) { 1116 cache_clean_timer_del(bs); 1117 s->cache_clean_interval = r->cache_clean_interval; 1118 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 1119 } 1120 1121 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1122 s->crypto_opts = r->crypto_opts; 1123 } 1124 1125 static void qcow2_update_options_abort(BlockDriverState *bs, 1126 Qcow2ReopenState *r) 1127 { 1128 if (r->l2_table_cache) { 1129 qcow2_cache_destroy(r->l2_table_cache); 1130 } 1131 if (r->refcount_block_cache) { 1132 qcow2_cache_destroy(r->refcount_block_cache); 1133 } 1134 qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); 1135 } 1136 1137 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 1138 int flags, Error **errp) 1139 { 1140 Qcow2ReopenState r = {}; 1141 int ret; 1142 1143 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 1144 if (ret >= 0) { 1145 qcow2_update_options_commit(bs, &r); 1146 } else { 1147 qcow2_update_options_abort(bs, &r); 1148 } 1149 1150 return ret; 1151 } 1152 1153 /* Called with s->lock held. */ 1154 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, 1155 int flags, Error **errp) 1156 { 1157 BDRVQcow2State *s = bs->opaque; 1158 unsigned int len, i; 1159 int ret = 0; 1160 QCowHeader header; 1161 Error *local_err = NULL; 1162 uint64_t ext_end; 1163 uint64_t l1_vm_state_index; 1164 bool update_header = false; 1165 1166 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 1167 if (ret < 0) { 1168 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 1169 goto fail; 1170 } 1171 header.magic = be32_to_cpu(header.magic); 1172 header.version = be32_to_cpu(header.version); 1173 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 1174 header.backing_file_size = be32_to_cpu(header.backing_file_size); 1175 header.size = be64_to_cpu(header.size); 1176 header.cluster_bits = be32_to_cpu(header.cluster_bits); 1177 header.crypt_method = be32_to_cpu(header.crypt_method); 1178 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 1179 header.l1_size = be32_to_cpu(header.l1_size); 1180 header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset); 1181 header.refcount_table_clusters = 1182 be32_to_cpu(header.refcount_table_clusters); 1183 header.snapshots_offset = be64_to_cpu(header.snapshots_offset); 1184 header.nb_snapshots = be32_to_cpu(header.nb_snapshots); 1185 1186 if (header.magic != QCOW_MAGIC) { 1187 error_setg(errp, "Image is not in qcow2 format"); 1188 ret = -EINVAL; 1189 goto fail; 1190 } 1191 if (header.version < 2 || header.version > 3) { 1192 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 1193 ret = -ENOTSUP; 1194 goto fail; 1195 } 1196 1197 s->qcow_version = header.version; 1198 1199 /* Initialise cluster size */ 1200 if (header.cluster_bits < MIN_CLUSTER_BITS || 1201 header.cluster_bits > MAX_CLUSTER_BITS) { 1202 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 1203 header.cluster_bits); 1204 ret = -EINVAL; 1205 goto fail; 1206 } 1207 1208 s->cluster_bits = header.cluster_bits; 1209 s->cluster_size = 1 << s->cluster_bits; 1210 s->cluster_sectors = 1 << (s->cluster_bits - BDRV_SECTOR_BITS); 1211 1212 /* Initialise version 3 header fields */ 1213 if (header.version == 2) { 1214 header.incompatible_features = 0; 1215 header.compatible_features = 0; 1216 header.autoclear_features = 0; 1217 header.refcount_order = 4; 1218 header.header_length = 72; 1219 } else { 1220 header.incompatible_features = 1221 be64_to_cpu(header.incompatible_features); 1222 header.compatible_features = be64_to_cpu(header.compatible_features); 1223 header.autoclear_features = be64_to_cpu(header.autoclear_features); 1224 header.refcount_order = be32_to_cpu(header.refcount_order); 1225 header.header_length = be32_to_cpu(header.header_length); 1226 1227 if (header.header_length < 104) { 1228 error_setg(errp, "qcow2 header too short"); 1229 ret = -EINVAL; 1230 goto fail; 1231 } 1232 } 1233 1234 if (header.header_length > s->cluster_size) { 1235 error_setg(errp, "qcow2 header exceeds cluster size"); 1236 ret = -EINVAL; 1237 goto fail; 1238 } 1239 1240 if (header.header_length > sizeof(header)) { 1241 s->unknown_header_fields_size = header.header_length - sizeof(header); 1242 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 1243 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 1244 s->unknown_header_fields_size); 1245 if (ret < 0) { 1246 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 1247 "fields"); 1248 goto fail; 1249 } 1250 } 1251 1252 if (header.backing_file_offset > s->cluster_size) { 1253 error_setg(errp, "Invalid backing file offset"); 1254 ret = -EINVAL; 1255 goto fail; 1256 } 1257 1258 if (header.backing_file_offset) { 1259 ext_end = header.backing_file_offset; 1260 } else { 1261 ext_end = 1 << header.cluster_bits; 1262 } 1263 1264 /* Handle feature bits */ 1265 s->incompatible_features = header.incompatible_features; 1266 s->compatible_features = header.compatible_features; 1267 s->autoclear_features = header.autoclear_features; 1268 1269 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 1270 void *feature_table = NULL; 1271 qcow2_read_extensions(bs, header.header_length, ext_end, 1272 &feature_table, flags, NULL, NULL); 1273 report_unsupported_feature(errp, feature_table, 1274 s->incompatible_features & 1275 ~QCOW2_INCOMPAT_MASK); 1276 ret = -ENOTSUP; 1277 g_free(feature_table); 1278 goto fail; 1279 } 1280 1281 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 1282 /* Corrupt images may not be written to unless they are being repaired 1283 */ 1284 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 1285 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 1286 "read/write"); 1287 ret = -EACCES; 1288 goto fail; 1289 } 1290 } 1291 1292 /* Check support for various header values */ 1293 if (header.refcount_order > 6) { 1294 error_setg(errp, "Reference count entry width too large; may not " 1295 "exceed 64 bits"); 1296 ret = -EINVAL; 1297 goto fail; 1298 } 1299 s->refcount_order = header.refcount_order; 1300 s->refcount_bits = 1 << s->refcount_order; 1301 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 1302 s->refcount_max += s->refcount_max - 1; 1303 1304 s->crypt_method_header = header.crypt_method; 1305 if (s->crypt_method_header) { 1306 if (bdrv_uses_whitelist() && 1307 s->crypt_method_header == QCOW_CRYPT_AES) { 1308 error_setg(errp, 1309 "Use of AES-CBC encrypted qcow2 images is no longer " 1310 "supported in system emulators"); 1311 error_append_hint(errp, 1312 "You can use 'qemu-img convert' to convert your " 1313 "image to an alternative supported format, such " 1314 "as unencrypted qcow2, or raw with the LUKS " 1315 "format instead.\n"); 1316 ret = -ENOSYS; 1317 goto fail; 1318 } 1319 1320 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1321 s->crypt_physical_offset = false; 1322 } else { 1323 /* Assuming LUKS and any future crypt methods we 1324 * add will all use physical offsets, due to the 1325 * fact that the alternative is insecure... */ 1326 s->crypt_physical_offset = true; 1327 } 1328 1329 bs->encrypted = true; 1330 } 1331 1332 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 1333 s->l2_size = 1 << s->l2_bits; 1334 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 1335 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 1336 s->refcount_block_size = 1 << s->refcount_block_bits; 1337 bs->total_sectors = header.size / BDRV_SECTOR_SIZE; 1338 s->csize_shift = (62 - (s->cluster_bits - 8)); 1339 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1340 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1341 1342 s->refcount_table_offset = header.refcount_table_offset; 1343 s->refcount_table_size = 1344 header.refcount_table_clusters << (s->cluster_bits - 3); 1345 1346 if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) { 1347 error_setg(errp, "Image does not contain a reference count table"); 1348 ret = -EINVAL; 1349 goto fail; 1350 } 1351 1352 ret = qcow2_validate_table(bs, s->refcount_table_offset, 1353 header.refcount_table_clusters, 1354 s->cluster_size, QCOW_MAX_REFTABLE_SIZE, 1355 "Reference count table", errp); 1356 if (ret < 0) { 1357 goto fail; 1358 } 1359 1360 /* The total size in bytes of the snapshot table is checked in 1361 * qcow2_read_snapshots() because the size of each snapshot is 1362 * variable and we don't know it yet. 1363 * Here we only check the offset and number of snapshots. */ 1364 ret = qcow2_validate_table(bs, header.snapshots_offset, 1365 header.nb_snapshots, 1366 sizeof(QCowSnapshotHeader), 1367 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, 1368 "Snapshot table", errp); 1369 if (ret < 0) { 1370 goto fail; 1371 } 1372 1373 /* read the level 1 table */ 1374 ret = qcow2_validate_table(bs, header.l1_table_offset, 1375 header.l1_size, sizeof(uint64_t), 1376 QCOW_MAX_L1_SIZE, "Active L1 table", errp); 1377 if (ret < 0) { 1378 goto fail; 1379 } 1380 s->l1_size = header.l1_size; 1381 s->l1_table_offset = header.l1_table_offset; 1382 1383 l1_vm_state_index = size_to_l1(s, header.size); 1384 if (l1_vm_state_index > INT_MAX) { 1385 error_setg(errp, "Image is too big"); 1386 ret = -EFBIG; 1387 goto fail; 1388 } 1389 s->l1_vm_state_index = l1_vm_state_index; 1390 1391 /* the L1 table must contain at least enough entries to put 1392 header.size bytes */ 1393 if (s->l1_size < s->l1_vm_state_index) { 1394 error_setg(errp, "L1 table is too small"); 1395 ret = -EINVAL; 1396 goto fail; 1397 } 1398 1399 if (s->l1_size > 0) { 1400 s->l1_table = qemu_try_blockalign(bs->file->bs, 1401 ROUND_UP(s->l1_size * sizeof(uint64_t), 512)); 1402 if (s->l1_table == NULL) { 1403 error_setg(errp, "Could not allocate L1 table"); 1404 ret = -ENOMEM; 1405 goto fail; 1406 } 1407 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1408 s->l1_size * sizeof(uint64_t)); 1409 if (ret < 0) { 1410 error_setg_errno(errp, -ret, "Could not read L1 table"); 1411 goto fail; 1412 } 1413 for(i = 0;i < s->l1_size; i++) { 1414 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 1415 } 1416 } 1417 1418 /* Parse driver-specific options */ 1419 ret = qcow2_update_options(bs, options, flags, errp); 1420 if (ret < 0) { 1421 goto fail; 1422 } 1423 1424 s->flags = flags; 1425 1426 ret = qcow2_refcount_init(bs); 1427 if (ret != 0) { 1428 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1429 goto fail; 1430 } 1431 1432 QLIST_INIT(&s->cluster_allocs); 1433 QTAILQ_INIT(&s->discards); 1434 1435 /* read qcow2 extensions */ 1436 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1437 flags, &update_header, &local_err)) { 1438 error_propagate(errp, local_err); 1439 ret = -EINVAL; 1440 goto fail; 1441 } 1442 1443 /* qcow2_read_extension may have set up the crypto context 1444 * if the crypt method needs a header region, some methods 1445 * don't need header extensions, so must check here 1446 */ 1447 if (s->crypt_method_header && !s->crypto) { 1448 if (s->crypt_method_header == QCOW_CRYPT_AES) { 1449 unsigned int cflags = 0; 1450 if (flags & BDRV_O_NO_IO) { 1451 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 1452 } 1453 s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.", 1454 NULL, NULL, cflags, 1, errp); 1455 if (!s->crypto) { 1456 ret = -EINVAL; 1457 goto fail; 1458 } 1459 } else if (!(flags & BDRV_O_NO_IO)) { 1460 error_setg(errp, "Missing CRYPTO header for crypt method %d", 1461 s->crypt_method_header); 1462 ret = -EINVAL; 1463 goto fail; 1464 } 1465 } 1466 1467 /* read the backing file name */ 1468 if (header.backing_file_offset != 0) { 1469 len = header.backing_file_size; 1470 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1471 len >= sizeof(bs->backing_file)) { 1472 error_setg(errp, "Backing file name too long"); 1473 ret = -EINVAL; 1474 goto fail; 1475 } 1476 ret = bdrv_pread(bs->file, header.backing_file_offset, 1477 bs->backing_file, len); 1478 if (ret < 0) { 1479 error_setg_errno(errp, -ret, "Could not read backing file name"); 1480 goto fail; 1481 } 1482 bs->backing_file[len] = '\0'; 1483 s->image_backing_file = g_strdup(bs->backing_file); 1484 } 1485 1486 /* Internal snapshots */ 1487 s->snapshots_offset = header.snapshots_offset; 1488 s->nb_snapshots = header.nb_snapshots; 1489 1490 ret = qcow2_read_snapshots(bs); 1491 if (ret < 0) { 1492 error_setg_errno(errp, -ret, "Could not read snapshots"); 1493 goto fail; 1494 } 1495 1496 /* Clear unknown autoclear feature bits */ 1497 update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; 1498 update_header = 1499 update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); 1500 if (update_header) { 1501 s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; 1502 } 1503 1504 /* == Handle persistent dirty bitmaps == 1505 * 1506 * We want load dirty bitmaps in three cases: 1507 * 1508 * 1. Normal open of the disk in active mode, not related to invalidation 1509 * after migration. 1510 * 1511 * 2. Invalidation of the target vm after pre-copy phase of migration, if 1512 * bitmaps are _not_ migrating through migration channel, i.e. 1513 * 'dirty-bitmaps' capability is disabled. 1514 * 1515 * 3. Invalidation of source vm after failed or canceled migration. 1516 * This is a very interesting case. There are two possible types of 1517 * bitmaps: 1518 * 1519 * A. Stored on inactivation and removed. They should be loaded from the 1520 * image. 1521 * 1522 * B. Not stored: not-persistent bitmaps and bitmaps, migrated through 1523 * the migration channel (with dirty-bitmaps capability). 1524 * 1525 * On the other hand, there are two possible sub-cases: 1526 * 1527 * 3.1 disk was changed by somebody else while were inactive. In this 1528 * case all in-RAM dirty bitmaps (both persistent and not) are 1529 * definitely invalid. And we don't have any method to determine 1530 * this. 1531 * 1532 * Simple and safe thing is to just drop all the bitmaps of type B on 1533 * inactivation. But in this case we lose bitmaps in valid 4.2 case. 1534 * 1535 * On the other hand, resuming source vm, if disk was already changed 1536 * is a bad thing anyway: not only bitmaps, the whole vm state is 1537 * out of sync with disk. 1538 * 1539 * This means, that user or management tool, who for some reason 1540 * decided to resume source vm, after disk was already changed by 1541 * target vm, should at least drop all dirty bitmaps by hand. 1542 * 1543 * So, we can ignore this case for now, but TODO: "generation" 1544 * extension for qcow2, to determine, that image was changed after 1545 * last inactivation. And if it is changed, we will drop (or at least 1546 * mark as 'invalid' all the bitmaps of type B, both persistent 1547 * and not). 1548 * 1549 * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved 1550 * to disk ('dirty-bitmaps' capability disabled), or not saved 1551 * ('dirty-bitmaps' capability enabled), but we don't need to care 1552 * of: let's load bitmaps as always: stored bitmaps will be loaded, 1553 * and not stored has flag IN_USE=1 in the image and will be skipped 1554 * on loading. 1555 * 1556 * One remaining possible case when we don't want load bitmaps: 1557 * 1558 * 4. Open disk in inactive mode in target vm (bitmaps are migrating or 1559 * will be loaded on invalidation, no needs try loading them before) 1560 */ 1561 1562 if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { 1563 /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ 1564 bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); 1565 1566 update_header = update_header && !header_updated; 1567 } 1568 if (local_err != NULL) { 1569 error_propagate(errp, local_err); 1570 ret = -EINVAL; 1571 goto fail; 1572 } 1573 1574 if (update_header) { 1575 ret = qcow2_update_header(bs); 1576 if (ret < 0) { 1577 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1578 goto fail; 1579 } 1580 } 1581 1582 bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0; 1583 1584 /* Repair image if dirty */ 1585 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1586 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1587 BdrvCheckResult result = {0}; 1588 1589 ret = qcow2_co_check_locked(bs, &result, 1590 BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1591 if (ret < 0 || result.check_errors) { 1592 if (ret >= 0) { 1593 ret = -EIO; 1594 } 1595 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1596 goto fail; 1597 } 1598 } 1599 1600 #ifdef DEBUG_ALLOC 1601 { 1602 BdrvCheckResult result = {0}; 1603 qcow2_check_refcounts(bs, &result, 0); 1604 } 1605 #endif 1606 1607 qemu_co_queue_init(&s->compress_wait_queue); 1608 1609 return ret; 1610 1611 fail: 1612 g_free(s->unknown_header_fields); 1613 cleanup_unknown_header_ext(bs); 1614 qcow2_free_snapshots(bs); 1615 qcow2_refcount_close(bs); 1616 qemu_vfree(s->l1_table); 1617 /* else pre-write overlap checks in cache_destroy may crash */ 1618 s->l1_table = NULL; 1619 cache_clean_timer_del(bs); 1620 if (s->l2_table_cache) { 1621 qcow2_cache_destroy(s->l2_table_cache); 1622 } 1623 if (s->refcount_block_cache) { 1624 qcow2_cache_destroy(s->refcount_block_cache); 1625 } 1626 qcrypto_block_free(s->crypto); 1627 qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); 1628 return ret; 1629 } 1630 1631 typedef struct QCow2OpenCo { 1632 BlockDriverState *bs; 1633 QDict *options; 1634 int flags; 1635 Error **errp; 1636 int ret; 1637 } QCow2OpenCo; 1638 1639 static void coroutine_fn qcow2_open_entry(void *opaque) 1640 { 1641 QCow2OpenCo *qoc = opaque; 1642 BDRVQcow2State *s = qoc->bs->opaque; 1643 1644 qemu_co_mutex_lock(&s->lock); 1645 qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); 1646 qemu_co_mutex_unlock(&s->lock); 1647 } 1648 1649 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1650 Error **errp) 1651 { 1652 BDRVQcow2State *s = bs->opaque; 1653 QCow2OpenCo qoc = { 1654 .bs = bs, 1655 .options = options, 1656 .flags = flags, 1657 .errp = errp, 1658 .ret = -EINPROGRESS 1659 }; 1660 1661 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1662 false, errp); 1663 if (!bs->file) { 1664 return -EINVAL; 1665 } 1666 1667 /* Initialise locks */ 1668 qemu_co_mutex_init(&s->lock); 1669 1670 if (qemu_in_coroutine()) { 1671 /* From bdrv_co_create. */ 1672 qcow2_open_entry(&qoc); 1673 } else { 1674 qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); 1675 BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); 1676 } 1677 return qoc.ret; 1678 } 1679 1680 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1681 { 1682 BDRVQcow2State *s = bs->opaque; 1683 1684 if (bs->encrypted) { 1685 /* Encryption works on a sector granularity */ 1686 bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto); 1687 } 1688 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1689 bs->bl.pdiscard_alignment = s->cluster_size; 1690 } 1691 1692 static int qcow2_reopen_prepare(BDRVReopenState *state, 1693 BlockReopenQueue *queue, Error **errp) 1694 { 1695 Qcow2ReopenState *r; 1696 int ret; 1697 1698 r = g_new0(Qcow2ReopenState, 1); 1699 state->opaque = r; 1700 1701 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1702 state->flags, errp); 1703 if (ret < 0) { 1704 goto fail; 1705 } 1706 1707 /* We need to write out any unwritten data if we reopen read-only. */ 1708 if ((state->flags & BDRV_O_RDWR) == 0) { 1709 ret = qcow2_reopen_bitmaps_ro(state->bs, errp); 1710 if (ret < 0) { 1711 goto fail; 1712 } 1713 1714 ret = bdrv_flush(state->bs); 1715 if (ret < 0) { 1716 goto fail; 1717 } 1718 1719 ret = qcow2_mark_clean(state->bs); 1720 if (ret < 0) { 1721 goto fail; 1722 } 1723 } 1724 1725 return 0; 1726 1727 fail: 1728 qcow2_update_options_abort(state->bs, r); 1729 g_free(r); 1730 return ret; 1731 } 1732 1733 static void qcow2_reopen_commit(BDRVReopenState *state) 1734 { 1735 qcow2_update_options_commit(state->bs, state->opaque); 1736 g_free(state->opaque); 1737 } 1738 1739 static void qcow2_reopen_abort(BDRVReopenState *state) 1740 { 1741 qcow2_update_options_abort(state->bs, state->opaque); 1742 g_free(state->opaque); 1743 } 1744 1745 static void qcow2_join_options(QDict *options, QDict *old_options) 1746 { 1747 bool has_new_overlap_template = 1748 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1749 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1750 bool has_new_total_cache_size = 1751 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1752 bool has_all_cache_options; 1753 1754 /* New overlap template overrides all old overlap options */ 1755 if (has_new_overlap_template) { 1756 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1757 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1758 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1759 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1760 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1761 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1762 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1763 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1764 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1765 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1766 } 1767 1768 /* New total cache size overrides all old options */ 1769 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1770 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1771 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1772 } 1773 1774 qdict_join(options, old_options, false); 1775 1776 /* 1777 * If after merging all cache size options are set, an old total size is 1778 * overwritten. Do keep all options, however, if all three are new. The 1779 * resulting error message is what we want to happen. 1780 */ 1781 has_all_cache_options = 1782 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1783 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1784 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1785 1786 if (has_all_cache_options && !has_new_total_cache_size) { 1787 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1788 } 1789 } 1790 1791 static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, 1792 bool want_zero, 1793 int64_t offset, int64_t count, 1794 int64_t *pnum, int64_t *map, 1795 BlockDriverState **file) 1796 { 1797 BDRVQcow2State *s = bs->opaque; 1798 uint64_t cluster_offset; 1799 int index_in_cluster, ret; 1800 unsigned int bytes; 1801 int status = 0; 1802 1803 bytes = MIN(INT_MAX, count); 1804 qemu_co_mutex_lock(&s->lock); 1805 ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); 1806 qemu_co_mutex_unlock(&s->lock); 1807 if (ret < 0) { 1808 return ret; 1809 } 1810 1811 *pnum = bytes; 1812 1813 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1814 !s->crypto) { 1815 index_in_cluster = offset & (s->cluster_size - 1); 1816 *map = cluster_offset | index_in_cluster; 1817 *file = bs->file->bs; 1818 status |= BDRV_BLOCK_OFFSET_VALID; 1819 } 1820 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1821 status |= BDRV_BLOCK_ZERO; 1822 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1823 status |= BDRV_BLOCK_DATA; 1824 } 1825 return status; 1826 } 1827 1828 static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, 1829 QCowL2Meta **pl2meta, 1830 bool link_l2) 1831 { 1832 int ret = 0; 1833 QCowL2Meta *l2meta = *pl2meta; 1834 1835 while (l2meta != NULL) { 1836 QCowL2Meta *next; 1837 1838 if (link_l2) { 1839 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1840 if (ret) { 1841 goto out; 1842 } 1843 } else { 1844 qcow2_alloc_cluster_abort(bs, l2meta); 1845 } 1846 1847 /* Take the request off the list of running requests */ 1848 if (l2meta->nb_clusters != 0) { 1849 QLIST_REMOVE(l2meta, next_in_flight); 1850 } 1851 1852 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1853 1854 next = l2meta->next; 1855 g_free(l2meta); 1856 l2meta = next; 1857 } 1858 out: 1859 *pl2meta = l2meta; 1860 return ret; 1861 } 1862 1863 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1864 uint64_t bytes, QEMUIOVector *qiov, 1865 int flags) 1866 { 1867 BDRVQcow2State *s = bs->opaque; 1868 int offset_in_cluster; 1869 int ret; 1870 unsigned int cur_bytes; /* number of bytes in current iteration */ 1871 uint64_t cluster_offset = 0; 1872 uint64_t bytes_done = 0; 1873 QEMUIOVector hd_qiov; 1874 uint8_t *cluster_data = NULL; 1875 1876 qemu_iovec_init(&hd_qiov, qiov->niov); 1877 1878 qemu_co_mutex_lock(&s->lock); 1879 1880 while (bytes != 0) { 1881 1882 /* prepare next request */ 1883 cur_bytes = MIN(bytes, INT_MAX); 1884 if (s->crypto) { 1885 cur_bytes = MIN(cur_bytes, 1886 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1887 } 1888 1889 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1890 if (ret < 0) { 1891 goto fail; 1892 } 1893 1894 offset_in_cluster = offset_into_cluster(s, offset); 1895 1896 qemu_iovec_reset(&hd_qiov); 1897 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1898 1899 switch (ret) { 1900 case QCOW2_CLUSTER_UNALLOCATED: 1901 1902 if (bs->backing) { 1903 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1904 qemu_co_mutex_unlock(&s->lock); 1905 ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, 1906 &hd_qiov, 0); 1907 qemu_co_mutex_lock(&s->lock); 1908 if (ret < 0) { 1909 goto fail; 1910 } 1911 } else { 1912 /* Note: in this case, no need to wait */ 1913 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1914 } 1915 break; 1916 1917 case QCOW2_CLUSTER_ZERO_PLAIN: 1918 case QCOW2_CLUSTER_ZERO_ALLOC: 1919 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1920 break; 1921 1922 case QCOW2_CLUSTER_COMPRESSED: 1923 qemu_co_mutex_unlock(&s->lock); 1924 ret = qcow2_co_preadv_compressed(bs, cluster_offset, 1925 offset, cur_bytes, 1926 &hd_qiov); 1927 qemu_co_mutex_lock(&s->lock); 1928 if (ret < 0) { 1929 goto fail; 1930 } 1931 1932 break; 1933 1934 case QCOW2_CLUSTER_NORMAL: 1935 if ((cluster_offset & 511) != 0) { 1936 ret = -EIO; 1937 goto fail; 1938 } 1939 1940 if (bs->encrypted) { 1941 assert(s->crypto); 1942 1943 /* 1944 * For encrypted images, read everything into a temporary 1945 * contiguous buffer on which the AES functions can work. 1946 */ 1947 if (!cluster_data) { 1948 cluster_data = 1949 qemu_try_blockalign(bs->file->bs, 1950 QCOW_MAX_CRYPT_CLUSTERS 1951 * s->cluster_size); 1952 if (cluster_data == NULL) { 1953 ret = -ENOMEM; 1954 goto fail; 1955 } 1956 } 1957 1958 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1959 qemu_iovec_reset(&hd_qiov); 1960 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1961 } 1962 1963 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1964 qemu_co_mutex_unlock(&s->lock); 1965 ret = bdrv_co_preadv(bs->file, 1966 cluster_offset + offset_in_cluster, 1967 cur_bytes, &hd_qiov, 0); 1968 qemu_co_mutex_lock(&s->lock); 1969 if (ret < 0) { 1970 goto fail; 1971 } 1972 if (bs->encrypted) { 1973 assert(s->crypto); 1974 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1975 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1976 if (qcrypto_block_decrypt(s->crypto, 1977 (s->crypt_physical_offset ? 1978 cluster_offset + offset_in_cluster : 1979 offset), 1980 cluster_data, 1981 cur_bytes, 1982 NULL) < 0) { 1983 ret = -EIO; 1984 goto fail; 1985 } 1986 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1987 } 1988 break; 1989 1990 default: 1991 g_assert_not_reached(); 1992 ret = -EIO; 1993 goto fail; 1994 } 1995 1996 bytes -= cur_bytes; 1997 offset += cur_bytes; 1998 bytes_done += cur_bytes; 1999 } 2000 ret = 0; 2001 2002 fail: 2003 qemu_co_mutex_unlock(&s->lock); 2004 2005 qemu_iovec_destroy(&hd_qiov); 2006 qemu_vfree(cluster_data); 2007 2008 return ret; 2009 } 2010 2011 /* Check if it's possible to merge a write request with the writing of 2012 * the data from the COW regions */ 2013 static bool merge_cow(uint64_t offset, unsigned bytes, 2014 QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) 2015 { 2016 QCowL2Meta *m; 2017 2018 for (m = l2meta; m != NULL; m = m->next) { 2019 /* If both COW regions are empty then there's nothing to merge */ 2020 if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { 2021 continue; 2022 } 2023 2024 /* The data (middle) region must be immediately after the 2025 * start region */ 2026 if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { 2027 continue; 2028 } 2029 2030 /* The end region must be immediately after the data (middle) 2031 * region */ 2032 if (m->offset + m->cow_end.offset != offset + bytes) { 2033 continue; 2034 } 2035 2036 /* Make sure that adding both COW regions to the QEMUIOVector 2037 * does not exceed IOV_MAX */ 2038 if (hd_qiov->niov > IOV_MAX - 2) { 2039 continue; 2040 } 2041 2042 m->data_qiov = hd_qiov; 2043 return true; 2044 } 2045 2046 return false; 2047 } 2048 2049 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 2050 uint64_t bytes, QEMUIOVector *qiov, 2051 int flags) 2052 { 2053 BDRVQcow2State *s = bs->opaque; 2054 int offset_in_cluster; 2055 int ret; 2056 unsigned int cur_bytes; /* number of sectors in current iteration */ 2057 uint64_t cluster_offset; 2058 QEMUIOVector hd_qiov; 2059 uint64_t bytes_done = 0; 2060 uint8_t *cluster_data = NULL; 2061 QCowL2Meta *l2meta = NULL; 2062 2063 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 2064 2065 qemu_iovec_init(&hd_qiov, qiov->niov); 2066 2067 qemu_co_mutex_lock(&s->lock); 2068 2069 while (bytes != 0) { 2070 2071 l2meta = NULL; 2072 2073 trace_qcow2_writev_start_part(qemu_coroutine_self()); 2074 offset_in_cluster = offset_into_cluster(s, offset); 2075 cur_bytes = MIN(bytes, INT_MAX); 2076 if (bs->encrypted) { 2077 cur_bytes = MIN(cur_bytes, 2078 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 2079 - offset_in_cluster); 2080 } 2081 2082 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2083 &cluster_offset, &l2meta); 2084 if (ret < 0) { 2085 goto fail; 2086 } 2087 2088 assert((cluster_offset & 511) == 0); 2089 2090 qemu_iovec_reset(&hd_qiov); 2091 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 2092 2093 if (bs->encrypted) { 2094 assert(s->crypto); 2095 if (!cluster_data) { 2096 cluster_data = qemu_try_blockalign(bs->file->bs, 2097 QCOW_MAX_CRYPT_CLUSTERS 2098 * s->cluster_size); 2099 if (cluster_data == NULL) { 2100 ret = -ENOMEM; 2101 goto fail; 2102 } 2103 } 2104 2105 assert(hd_qiov.size <= 2106 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 2107 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 2108 2109 if (qcrypto_block_encrypt(s->crypto, 2110 (s->crypt_physical_offset ? 2111 cluster_offset + offset_in_cluster : 2112 offset), 2113 cluster_data, 2114 cur_bytes, NULL) < 0) { 2115 ret = -EIO; 2116 goto fail; 2117 } 2118 2119 qemu_iovec_reset(&hd_qiov); 2120 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 2121 } 2122 2123 ret = qcow2_pre_write_overlap_check(bs, 0, 2124 cluster_offset + offset_in_cluster, cur_bytes); 2125 if (ret < 0) { 2126 goto fail; 2127 } 2128 2129 /* If we need to do COW, check if it's possible to merge the 2130 * writing of the guest data together with that of the COW regions. 2131 * If it's not possible (or not necessary) then write the 2132 * guest data now. */ 2133 if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { 2134 qemu_co_mutex_unlock(&s->lock); 2135 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 2136 trace_qcow2_writev_data(qemu_coroutine_self(), 2137 cluster_offset + offset_in_cluster); 2138 ret = bdrv_co_pwritev(bs->file, 2139 cluster_offset + offset_in_cluster, 2140 cur_bytes, &hd_qiov, 0); 2141 qemu_co_mutex_lock(&s->lock); 2142 if (ret < 0) { 2143 goto fail; 2144 } 2145 } 2146 2147 ret = qcow2_handle_l2meta(bs, &l2meta, true); 2148 if (ret) { 2149 goto fail; 2150 } 2151 2152 bytes -= cur_bytes; 2153 offset += cur_bytes; 2154 bytes_done += cur_bytes; 2155 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 2156 } 2157 ret = 0; 2158 2159 fail: 2160 qcow2_handle_l2meta(bs, &l2meta, false); 2161 2162 qemu_co_mutex_unlock(&s->lock); 2163 2164 qemu_iovec_destroy(&hd_qiov); 2165 qemu_vfree(cluster_data); 2166 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 2167 2168 return ret; 2169 } 2170 2171 static int qcow2_inactivate(BlockDriverState *bs) 2172 { 2173 BDRVQcow2State *s = bs->opaque; 2174 int ret, result = 0; 2175 Error *local_err = NULL; 2176 2177 qcow2_store_persistent_dirty_bitmaps(bs, &local_err); 2178 if (local_err != NULL) { 2179 result = -EINVAL; 2180 error_reportf_err(local_err, "Lost persistent bitmaps during " 2181 "inactivation of node '%s': ", 2182 bdrv_get_device_or_node_name(bs)); 2183 } 2184 2185 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2186 if (ret) { 2187 result = ret; 2188 error_report("Failed to flush the L2 table cache: %s", 2189 strerror(-ret)); 2190 } 2191 2192 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2193 if (ret) { 2194 result = ret; 2195 error_report("Failed to flush the refcount block cache: %s", 2196 strerror(-ret)); 2197 } 2198 2199 if (result == 0) { 2200 qcow2_mark_clean(bs); 2201 } 2202 2203 return result; 2204 } 2205 2206 static void qcow2_close(BlockDriverState *bs) 2207 { 2208 BDRVQcow2State *s = bs->opaque; 2209 qemu_vfree(s->l1_table); 2210 /* else pre-write overlap checks in cache_destroy may crash */ 2211 s->l1_table = NULL; 2212 2213 if (!(s->flags & BDRV_O_INACTIVE)) { 2214 qcow2_inactivate(bs); 2215 } 2216 2217 cache_clean_timer_del(bs); 2218 qcow2_cache_destroy(s->l2_table_cache); 2219 qcow2_cache_destroy(s->refcount_block_cache); 2220 2221 qcrypto_block_free(s->crypto); 2222 s->crypto = NULL; 2223 2224 g_free(s->unknown_header_fields); 2225 cleanup_unknown_header_ext(bs); 2226 2227 g_free(s->image_backing_file); 2228 g_free(s->image_backing_format); 2229 2230 qcow2_refcount_close(bs); 2231 qcow2_free_snapshots(bs); 2232 } 2233 2234 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, 2235 Error **errp) 2236 { 2237 BDRVQcow2State *s = bs->opaque; 2238 int flags = s->flags; 2239 QCryptoBlock *crypto = NULL; 2240 QDict *options; 2241 Error *local_err = NULL; 2242 int ret; 2243 2244 /* 2245 * Backing files are read-only which makes all of their metadata immutable, 2246 * that means we don't have to worry about reopening them here. 2247 */ 2248 2249 crypto = s->crypto; 2250 s->crypto = NULL; 2251 2252 qcow2_close(bs); 2253 2254 memset(s, 0, sizeof(BDRVQcow2State)); 2255 options = qdict_clone_shallow(bs->options); 2256 2257 flags &= ~BDRV_O_INACTIVE; 2258 qemu_co_mutex_lock(&s->lock); 2259 ret = qcow2_do_open(bs, options, flags, &local_err); 2260 qemu_co_mutex_unlock(&s->lock); 2261 qobject_unref(options); 2262 if (local_err) { 2263 error_propagate_prepend(errp, local_err, 2264 "Could not reopen qcow2 layer: "); 2265 bs->drv = NULL; 2266 return; 2267 } else if (ret < 0) { 2268 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 2269 bs->drv = NULL; 2270 return; 2271 } 2272 2273 s->crypto = crypto; 2274 } 2275 2276 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 2277 size_t len, size_t buflen) 2278 { 2279 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 2280 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 2281 2282 if (buflen < ext_len) { 2283 return -ENOSPC; 2284 } 2285 2286 *ext_backing_fmt = (QCowExtension) { 2287 .magic = cpu_to_be32(magic), 2288 .len = cpu_to_be32(len), 2289 }; 2290 2291 if (len) { 2292 memcpy(buf + sizeof(QCowExtension), s, len); 2293 } 2294 2295 return ext_len; 2296 } 2297 2298 /* 2299 * Updates the qcow2 header, including the variable length parts of it, i.e. 2300 * the backing file name and all extensions. qcow2 was not designed to allow 2301 * such changes, so if we run out of space (we can only use the first cluster) 2302 * this function may fail. 2303 * 2304 * Returns 0 on success, -errno in error cases. 2305 */ 2306 int qcow2_update_header(BlockDriverState *bs) 2307 { 2308 BDRVQcow2State *s = bs->opaque; 2309 QCowHeader *header; 2310 char *buf; 2311 size_t buflen = s->cluster_size; 2312 int ret; 2313 uint64_t total_size; 2314 uint32_t refcount_table_clusters; 2315 size_t header_length; 2316 Qcow2UnknownHeaderExtension *uext; 2317 2318 buf = qemu_blockalign(bs, buflen); 2319 2320 /* Header structure */ 2321 header = (QCowHeader*) buf; 2322 2323 if (buflen < sizeof(*header)) { 2324 ret = -ENOSPC; 2325 goto fail; 2326 } 2327 2328 header_length = sizeof(*header) + s->unknown_header_fields_size; 2329 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 2330 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 2331 2332 *header = (QCowHeader) { 2333 /* Version 2 fields */ 2334 .magic = cpu_to_be32(QCOW_MAGIC), 2335 .version = cpu_to_be32(s->qcow_version), 2336 .backing_file_offset = 0, 2337 .backing_file_size = 0, 2338 .cluster_bits = cpu_to_be32(s->cluster_bits), 2339 .size = cpu_to_be64(total_size), 2340 .crypt_method = cpu_to_be32(s->crypt_method_header), 2341 .l1_size = cpu_to_be32(s->l1_size), 2342 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 2343 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 2344 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 2345 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 2346 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 2347 2348 /* Version 3 fields */ 2349 .incompatible_features = cpu_to_be64(s->incompatible_features), 2350 .compatible_features = cpu_to_be64(s->compatible_features), 2351 .autoclear_features = cpu_to_be64(s->autoclear_features), 2352 .refcount_order = cpu_to_be32(s->refcount_order), 2353 .header_length = cpu_to_be32(header_length), 2354 }; 2355 2356 /* For older versions, write a shorter header */ 2357 switch (s->qcow_version) { 2358 case 2: 2359 ret = offsetof(QCowHeader, incompatible_features); 2360 break; 2361 case 3: 2362 ret = sizeof(*header); 2363 break; 2364 default: 2365 ret = -EINVAL; 2366 goto fail; 2367 } 2368 2369 buf += ret; 2370 buflen -= ret; 2371 memset(buf, 0, buflen); 2372 2373 /* Preserve any unknown field in the header */ 2374 if (s->unknown_header_fields_size) { 2375 if (buflen < s->unknown_header_fields_size) { 2376 ret = -ENOSPC; 2377 goto fail; 2378 } 2379 2380 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 2381 buf += s->unknown_header_fields_size; 2382 buflen -= s->unknown_header_fields_size; 2383 } 2384 2385 /* Backing file format header extension */ 2386 if (s->image_backing_format) { 2387 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 2388 s->image_backing_format, 2389 strlen(s->image_backing_format), 2390 buflen); 2391 if (ret < 0) { 2392 goto fail; 2393 } 2394 2395 buf += ret; 2396 buflen -= ret; 2397 } 2398 2399 /* Full disk encryption header pointer extension */ 2400 if (s->crypto_header.offset != 0) { 2401 s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset); 2402 s->crypto_header.length = cpu_to_be64(s->crypto_header.length); 2403 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, 2404 &s->crypto_header, sizeof(s->crypto_header), 2405 buflen); 2406 s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); 2407 s->crypto_header.length = be64_to_cpu(s->crypto_header.length); 2408 if (ret < 0) { 2409 goto fail; 2410 } 2411 buf += ret; 2412 buflen -= ret; 2413 } 2414 2415 /* Feature table */ 2416 if (s->qcow_version >= 3) { 2417 Qcow2Feature features[] = { 2418 { 2419 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2420 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 2421 .name = "dirty bit", 2422 }, 2423 { 2424 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 2425 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 2426 .name = "corrupt bit", 2427 }, 2428 { 2429 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 2430 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 2431 .name = "lazy refcounts", 2432 }, 2433 }; 2434 2435 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 2436 features, sizeof(features), buflen); 2437 if (ret < 0) { 2438 goto fail; 2439 } 2440 buf += ret; 2441 buflen -= ret; 2442 } 2443 2444 /* Bitmap extension */ 2445 if (s->nb_bitmaps > 0) { 2446 Qcow2BitmapHeaderExt bitmaps_header = { 2447 .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), 2448 .bitmap_directory_size = 2449 cpu_to_be64(s->bitmap_directory_size), 2450 .bitmap_directory_offset = 2451 cpu_to_be64(s->bitmap_directory_offset) 2452 }; 2453 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, 2454 &bitmaps_header, sizeof(bitmaps_header), 2455 buflen); 2456 if (ret < 0) { 2457 goto fail; 2458 } 2459 buf += ret; 2460 buflen -= ret; 2461 } 2462 2463 /* Keep unknown header extensions */ 2464 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 2465 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 2466 if (ret < 0) { 2467 goto fail; 2468 } 2469 2470 buf += ret; 2471 buflen -= ret; 2472 } 2473 2474 /* End of header extensions */ 2475 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 2476 if (ret < 0) { 2477 goto fail; 2478 } 2479 2480 buf += ret; 2481 buflen -= ret; 2482 2483 /* Backing file name */ 2484 if (s->image_backing_file) { 2485 size_t backing_file_len = strlen(s->image_backing_file); 2486 2487 if (buflen < backing_file_len) { 2488 ret = -ENOSPC; 2489 goto fail; 2490 } 2491 2492 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 2493 strncpy(buf, s->image_backing_file, buflen); 2494 2495 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2496 header->backing_file_size = cpu_to_be32(backing_file_len); 2497 } 2498 2499 /* Write the new header */ 2500 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2501 if (ret < 0) { 2502 goto fail; 2503 } 2504 2505 ret = 0; 2506 fail: 2507 qemu_vfree(header); 2508 return ret; 2509 } 2510 2511 static int qcow2_change_backing_file(BlockDriverState *bs, 2512 const char *backing_file, const char *backing_fmt) 2513 { 2514 BDRVQcow2State *s = bs->opaque; 2515 2516 if (backing_file && strlen(backing_file) > 1023) { 2517 return -EINVAL; 2518 } 2519 2520 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2521 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2522 2523 g_free(s->image_backing_file); 2524 g_free(s->image_backing_format); 2525 2526 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2527 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2528 2529 return qcow2_update_header(bs); 2530 } 2531 2532 static int qcow2_crypt_method_from_format(const char *encryptfmt) 2533 { 2534 if (g_str_equal(encryptfmt, "luks")) { 2535 return QCOW_CRYPT_LUKS; 2536 } else if (g_str_equal(encryptfmt, "aes")) { 2537 return QCOW_CRYPT_AES; 2538 } else { 2539 return -EINVAL; 2540 } 2541 } 2542 2543 static int qcow2_set_up_encryption(BlockDriverState *bs, 2544 QCryptoBlockCreateOptions *cryptoopts, 2545 Error **errp) 2546 { 2547 BDRVQcow2State *s = bs->opaque; 2548 QCryptoBlock *crypto = NULL; 2549 int fmt, ret; 2550 2551 switch (cryptoopts->format) { 2552 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 2553 fmt = QCOW_CRYPT_LUKS; 2554 break; 2555 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 2556 fmt = QCOW_CRYPT_AES; 2557 break; 2558 default: 2559 error_setg(errp, "Crypto format not supported in qcow2"); 2560 return -EINVAL; 2561 } 2562 2563 s->crypt_method_header = fmt; 2564 2565 crypto = qcrypto_block_create(cryptoopts, "encrypt.", 2566 qcow2_crypto_hdr_init_func, 2567 qcow2_crypto_hdr_write_func, 2568 bs, errp); 2569 if (!crypto) { 2570 return -EINVAL; 2571 } 2572 2573 ret = qcow2_update_header(bs); 2574 if (ret < 0) { 2575 error_setg_errno(errp, -ret, "Could not write encryption header"); 2576 goto out; 2577 } 2578 2579 ret = 0; 2580 out: 2581 qcrypto_block_free(crypto); 2582 return ret; 2583 } 2584 2585 /** 2586 * Preallocates metadata structures for data clusters between @offset (in the 2587 * guest disk) and @new_length (which is thus generally the new guest disk 2588 * size). 2589 * 2590 * Returns: 0 on success, -errno on failure. 2591 */ 2592 static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, 2593 uint64_t new_length) 2594 { 2595 uint64_t bytes; 2596 uint64_t host_offset = 0; 2597 unsigned int cur_bytes; 2598 int ret; 2599 QCowL2Meta *meta; 2600 2601 assert(offset <= new_length); 2602 bytes = new_length - offset; 2603 2604 while (bytes) { 2605 cur_bytes = MIN(bytes, INT_MAX); 2606 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2607 &host_offset, &meta); 2608 if (ret < 0) { 2609 return ret; 2610 } 2611 2612 while (meta) { 2613 QCowL2Meta *next = meta->next; 2614 2615 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2616 if (ret < 0) { 2617 qcow2_free_any_clusters(bs, meta->alloc_offset, 2618 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2619 return ret; 2620 } 2621 2622 /* There are no dependent requests, but we need to remove our 2623 * request from the list of in-flight requests */ 2624 QLIST_REMOVE(meta, next_in_flight); 2625 2626 g_free(meta); 2627 meta = next; 2628 } 2629 2630 /* TODO Preallocate data if requested */ 2631 2632 bytes -= cur_bytes; 2633 offset += cur_bytes; 2634 } 2635 2636 /* 2637 * It is expected that the image file is large enough to actually contain 2638 * all of the allocated clusters (otherwise we get failing reads after 2639 * EOF). Extend the image to the last allocated sector. 2640 */ 2641 if (host_offset != 0) { 2642 uint8_t data = 0; 2643 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2644 &data, 1); 2645 if (ret < 0) { 2646 return ret; 2647 } 2648 } 2649 2650 return 0; 2651 } 2652 2653 /* qcow2_refcount_metadata_size: 2654 * @clusters: number of clusters to refcount (including data and L1/L2 tables) 2655 * @cluster_size: size of a cluster, in bytes 2656 * @refcount_order: refcount bits power-of-2 exponent 2657 * @generous_increase: allow for the refcount table to be 1.5x as large as it 2658 * needs to be 2659 * 2660 * Returns: Number of bytes required for refcount blocks and table metadata. 2661 */ 2662 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, 2663 int refcount_order, bool generous_increase, 2664 uint64_t *refblock_count) 2665 { 2666 /* 2667 * Every host cluster is reference-counted, including metadata (even 2668 * refcount metadata is recursively included). 2669 * 2670 * An accurate formula for the size of refcount metadata size is difficult 2671 * to derive. An easier method of calculation is finding the fixed point 2672 * where no further refcount blocks or table clusters are required to 2673 * reference count every cluster. 2674 */ 2675 int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t); 2676 int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); 2677 int64_t table = 0; /* number of refcount table clusters */ 2678 int64_t blocks = 0; /* number of refcount block clusters */ 2679 int64_t last; 2680 int64_t n = 0; 2681 2682 do { 2683 last = n; 2684 blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); 2685 table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); 2686 n = clusters + blocks + table; 2687 2688 if (n == last && generous_increase) { 2689 clusters += DIV_ROUND_UP(table, 2); 2690 n = 0; /* force another loop */ 2691 generous_increase = false; 2692 } 2693 } while (n != last); 2694 2695 if (refblock_count) { 2696 *refblock_count = blocks; 2697 } 2698 2699 return (blocks + table) * cluster_size; 2700 } 2701 2702 /** 2703 * qcow2_calc_prealloc_size: 2704 * @total_size: virtual disk size in bytes 2705 * @cluster_size: cluster size in bytes 2706 * @refcount_order: refcount bits power-of-2 exponent 2707 * 2708 * Returns: Total number of bytes required for the fully allocated image 2709 * (including metadata). 2710 */ 2711 static int64_t qcow2_calc_prealloc_size(int64_t total_size, 2712 size_t cluster_size, 2713 int refcount_order) 2714 { 2715 int64_t meta_size = 0; 2716 uint64_t nl1e, nl2e; 2717 int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); 2718 2719 /* header: 1 cluster */ 2720 meta_size += cluster_size; 2721 2722 /* total size of L2 tables */ 2723 nl2e = aligned_total_size / cluster_size; 2724 nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t)); 2725 meta_size += nl2e * sizeof(uint64_t); 2726 2727 /* total size of L1 tables */ 2728 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2729 nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t)); 2730 meta_size += nl1e * sizeof(uint64_t); 2731 2732 /* total size of refcount table and blocks */ 2733 meta_size += qcow2_refcount_metadata_size( 2734 (meta_size + aligned_total_size) / cluster_size, 2735 cluster_size, refcount_order, false, NULL); 2736 2737 return meta_size + aligned_total_size; 2738 } 2739 2740 static bool validate_cluster_size(size_t cluster_size, Error **errp) 2741 { 2742 int cluster_bits = ctz32(cluster_size); 2743 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2744 (1 << cluster_bits) != cluster_size) 2745 { 2746 error_setg(errp, "Cluster size must be a power of two between %d and " 2747 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2748 return false; 2749 } 2750 return true; 2751 } 2752 2753 static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) 2754 { 2755 size_t cluster_size; 2756 2757 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2758 DEFAULT_CLUSTER_SIZE); 2759 if (!validate_cluster_size(cluster_size, errp)) { 2760 return 0; 2761 } 2762 return cluster_size; 2763 } 2764 2765 static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) 2766 { 2767 char *buf; 2768 int ret; 2769 2770 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2771 if (!buf) { 2772 ret = 3; /* default */ 2773 } else if (!strcmp(buf, "0.10")) { 2774 ret = 2; 2775 } else if (!strcmp(buf, "1.1")) { 2776 ret = 3; 2777 } else { 2778 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2779 ret = -EINVAL; 2780 } 2781 g_free(buf); 2782 return ret; 2783 } 2784 2785 static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, 2786 Error **errp) 2787 { 2788 uint64_t refcount_bits; 2789 2790 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); 2791 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2792 error_setg(errp, "Refcount width must be a power of two and may not " 2793 "exceed 64 bits"); 2794 return 0; 2795 } 2796 2797 if (version < 3 && refcount_bits != 16) { 2798 error_setg(errp, "Different refcount widths than 16 bits require " 2799 "compatibility level 1.1 or above (use compat=1.1 or " 2800 "greater)"); 2801 return 0; 2802 } 2803 2804 return refcount_bits; 2805 } 2806 2807 static int coroutine_fn 2808 qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 2809 { 2810 BlockdevCreateOptionsQcow2 *qcow2_opts; 2811 QDict *options; 2812 2813 /* 2814 * Open the image file and write a minimal qcow2 header. 2815 * 2816 * We keep things simple and start with a zero-sized image. We also 2817 * do without refcount blocks or a L1 table for now. We'll fix the 2818 * inconsistency later. 2819 * 2820 * We do need a refcount table because growing the refcount table means 2821 * allocating two new refcount blocks - the seconds of which would be at 2822 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2823 * size for any qcow2 image. 2824 */ 2825 BlockBackend *blk = NULL; 2826 BlockDriverState *bs = NULL; 2827 QCowHeader *header; 2828 size_t cluster_size; 2829 int version; 2830 int refcount_order; 2831 uint64_t* refcount_table; 2832 Error *local_err = NULL; 2833 int ret; 2834 2835 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); 2836 qcow2_opts = &create_options->u.qcow2; 2837 2838 bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); 2839 if (bs == NULL) { 2840 return -EIO; 2841 } 2842 2843 /* Validate options and set default values */ 2844 if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { 2845 error_setg(errp, "Image size must be a multiple of 512 bytes"); 2846 ret = -EINVAL; 2847 goto out; 2848 } 2849 2850 if (qcow2_opts->has_version) { 2851 switch (qcow2_opts->version) { 2852 case BLOCKDEV_QCOW2_VERSION_V2: 2853 version = 2; 2854 break; 2855 case BLOCKDEV_QCOW2_VERSION_V3: 2856 version = 3; 2857 break; 2858 default: 2859 g_assert_not_reached(); 2860 } 2861 } else { 2862 version = 3; 2863 } 2864 2865 if (qcow2_opts->has_cluster_size) { 2866 cluster_size = qcow2_opts->cluster_size; 2867 } else { 2868 cluster_size = DEFAULT_CLUSTER_SIZE; 2869 } 2870 2871 if (!validate_cluster_size(cluster_size, errp)) { 2872 ret = -EINVAL; 2873 goto out; 2874 } 2875 2876 if (!qcow2_opts->has_preallocation) { 2877 qcow2_opts->preallocation = PREALLOC_MODE_OFF; 2878 } 2879 if (qcow2_opts->has_backing_file && 2880 qcow2_opts->preallocation != PREALLOC_MODE_OFF) 2881 { 2882 error_setg(errp, "Backing file and preallocation cannot be used at " 2883 "the same time"); 2884 ret = -EINVAL; 2885 goto out; 2886 } 2887 if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { 2888 error_setg(errp, "Backing format cannot be used without backing file"); 2889 ret = -EINVAL; 2890 goto out; 2891 } 2892 2893 if (!qcow2_opts->has_lazy_refcounts) { 2894 qcow2_opts->lazy_refcounts = false; 2895 } 2896 if (version < 3 && qcow2_opts->lazy_refcounts) { 2897 error_setg(errp, "Lazy refcounts only supported with compatibility " 2898 "level 1.1 and above (use version=v3 or greater)"); 2899 ret = -EINVAL; 2900 goto out; 2901 } 2902 2903 if (!qcow2_opts->has_refcount_bits) { 2904 qcow2_opts->refcount_bits = 16; 2905 } 2906 if (qcow2_opts->refcount_bits > 64 || 2907 !is_power_of_2(qcow2_opts->refcount_bits)) 2908 { 2909 error_setg(errp, "Refcount width must be a power of two and may not " 2910 "exceed 64 bits"); 2911 ret = -EINVAL; 2912 goto out; 2913 } 2914 if (version < 3 && qcow2_opts->refcount_bits != 16) { 2915 error_setg(errp, "Different refcount widths than 16 bits require " 2916 "compatibility level 1.1 or above (use version=v3 or " 2917 "greater)"); 2918 ret = -EINVAL; 2919 goto out; 2920 } 2921 refcount_order = ctz32(qcow2_opts->refcount_bits); 2922 2923 2924 /* Create BlockBackend to write to the image */ 2925 blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 2926 ret = blk_insert_bs(blk, bs, errp); 2927 if (ret < 0) { 2928 goto out; 2929 } 2930 blk_set_allow_write_beyond_eof(blk, true); 2931 2932 /* Clear the protocol layer and preallocate it if necessary */ 2933 ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); 2934 if (ret < 0) { 2935 goto out; 2936 } 2937 2938 if (qcow2_opts->preallocation == PREALLOC_MODE_FULL || 2939 qcow2_opts->preallocation == PREALLOC_MODE_FALLOC) 2940 { 2941 int64_t prealloc_size = 2942 qcow2_calc_prealloc_size(qcow2_opts->size, cluster_size, 2943 refcount_order); 2944 2945 ret = blk_truncate(blk, prealloc_size, qcow2_opts->preallocation, errp); 2946 if (ret < 0) { 2947 goto out; 2948 } 2949 } 2950 2951 /* Write the header */ 2952 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2953 header = g_malloc0(cluster_size); 2954 *header = (QCowHeader) { 2955 .magic = cpu_to_be32(QCOW_MAGIC), 2956 .version = cpu_to_be32(version), 2957 .cluster_bits = cpu_to_be32(ctz32(cluster_size)), 2958 .size = cpu_to_be64(0), 2959 .l1_table_offset = cpu_to_be64(0), 2960 .l1_size = cpu_to_be32(0), 2961 .refcount_table_offset = cpu_to_be64(cluster_size), 2962 .refcount_table_clusters = cpu_to_be32(1), 2963 .refcount_order = cpu_to_be32(refcount_order), 2964 .header_length = cpu_to_be32(sizeof(*header)), 2965 }; 2966 2967 /* We'll update this to correct value later */ 2968 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2969 2970 if (qcow2_opts->lazy_refcounts) { 2971 header->compatible_features |= 2972 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2973 } 2974 2975 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2976 g_free(header); 2977 if (ret < 0) { 2978 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2979 goto out; 2980 } 2981 2982 /* Write a refcount table with one refcount block */ 2983 refcount_table = g_malloc0(2 * cluster_size); 2984 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2985 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2986 g_free(refcount_table); 2987 2988 if (ret < 0) { 2989 error_setg_errno(errp, -ret, "Could not write refcount table"); 2990 goto out; 2991 } 2992 2993 blk_unref(blk); 2994 blk = NULL; 2995 2996 /* 2997 * And now open the image and make it consistent first (i.e. increase the 2998 * refcount of the cluster that is occupied by the header and the refcount 2999 * table) 3000 */ 3001 options = qdict_new(); 3002 qdict_put_str(options, "driver", "qcow2"); 3003 qdict_put_str(options, "file", bs->node_name); 3004 blk = blk_new_open(NULL, NULL, options, 3005 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 3006 &local_err); 3007 if (blk == NULL) { 3008 error_propagate(errp, local_err); 3009 ret = -EIO; 3010 goto out; 3011 } 3012 3013 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 3014 if (ret < 0) { 3015 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 3016 "header and refcount table"); 3017 goto out; 3018 3019 } else if (ret != 0) { 3020 error_report("Huh, first cluster in empty image is already in use?"); 3021 abort(); 3022 } 3023 3024 /* Create a full header (including things like feature table) */ 3025 ret = qcow2_update_header(blk_bs(blk)); 3026 if (ret < 0) { 3027 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 3028 goto out; 3029 } 3030 3031 /* Okay, now that we have a valid image, let's give it the right size */ 3032 ret = blk_truncate(blk, qcow2_opts->size, PREALLOC_MODE_OFF, errp); 3033 if (ret < 0) { 3034 error_prepend(errp, "Could not resize image: "); 3035 goto out; 3036 } 3037 3038 /* Want a backing file? There you go.*/ 3039 if (qcow2_opts->has_backing_file) { 3040 const char *backing_format = NULL; 3041 3042 if (qcow2_opts->has_backing_fmt) { 3043 backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); 3044 } 3045 3046 ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, 3047 backing_format); 3048 if (ret < 0) { 3049 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 3050 "with format '%s'", qcow2_opts->backing_file, 3051 backing_format); 3052 goto out; 3053 } 3054 } 3055 3056 /* Want encryption? There you go. */ 3057 if (qcow2_opts->has_encrypt) { 3058 ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); 3059 if (ret < 0) { 3060 goto out; 3061 } 3062 } 3063 3064 /* And if we're supposed to preallocate metadata, do that now */ 3065 if (qcow2_opts->preallocation != PREALLOC_MODE_OFF) { 3066 BDRVQcow2State *s = blk_bs(blk)->opaque; 3067 qemu_co_mutex_lock(&s->lock); 3068 ret = preallocate_co(blk_bs(blk), 0, qcow2_opts->size); 3069 qemu_co_mutex_unlock(&s->lock); 3070 3071 if (ret < 0) { 3072 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 3073 goto out; 3074 } 3075 } 3076 3077 blk_unref(blk); 3078 blk = NULL; 3079 3080 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. 3081 * Using BDRV_O_NO_IO, since encryption is now setup we don't want to 3082 * have to setup decryption context. We're not doing any I/O on the top 3083 * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does 3084 * not have effect. 3085 */ 3086 options = qdict_new(); 3087 qdict_put_str(options, "driver", "qcow2"); 3088 qdict_put_str(options, "file", bs->node_name); 3089 blk = blk_new_open(NULL, NULL, options, 3090 BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, 3091 &local_err); 3092 if (blk == NULL) { 3093 error_propagate(errp, local_err); 3094 ret = -EIO; 3095 goto out; 3096 } 3097 3098 ret = 0; 3099 out: 3100 blk_unref(blk); 3101 bdrv_unref(bs); 3102 return ret; 3103 } 3104 3105 static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts, 3106 Error **errp) 3107 { 3108 BlockdevCreateOptions *create_options = NULL; 3109 QDict *qdict; 3110 Visitor *v; 3111 BlockDriverState *bs = NULL; 3112 Error *local_err = NULL; 3113 const char *val; 3114 int ret; 3115 3116 /* Only the keyval visitor supports the dotted syntax needed for 3117 * encryption, so go through a QDict before getting a QAPI type. Ignore 3118 * options meant for the protocol layer so that the visitor doesn't 3119 * complain. */ 3120 qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, 3121 true); 3122 3123 /* Handle encryption options */ 3124 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 3125 if (val && !strcmp(val, "on")) { 3126 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 3127 } else if (val && !strcmp(val, "off")) { 3128 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 3129 } 3130 3131 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 3132 if (val && !strcmp(val, "aes")) { 3133 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 3134 } 3135 3136 /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into 3137 * version=v2/v3 below. */ 3138 val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); 3139 if (val && !strcmp(val, "0.10")) { 3140 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); 3141 } else if (val && !strcmp(val, "1.1")) { 3142 qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); 3143 } 3144 3145 /* Change legacy command line options into QMP ones */ 3146 static const QDictRenames opt_renames[] = { 3147 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 3148 { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, 3149 { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, 3150 { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, 3151 { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, 3152 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 3153 { BLOCK_OPT_COMPAT_LEVEL, "version" }, 3154 { NULL, NULL }, 3155 }; 3156 3157 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 3158 ret = -EINVAL; 3159 goto finish; 3160 } 3161 3162 /* Create and open the file (protocol layer) */ 3163 ret = bdrv_create_file(filename, opts, errp); 3164 if (ret < 0) { 3165 goto finish; 3166 } 3167 3168 bs = bdrv_open(filename, NULL, NULL, 3169 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 3170 if (bs == NULL) { 3171 ret = -EIO; 3172 goto finish; 3173 } 3174 3175 /* Set 'driver' and 'node' options */ 3176 qdict_put_str(qdict, "driver", "qcow2"); 3177 qdict_put_str(qdict, "file", bs->node_name); 3178 3179 /* Now get the QAPI type BlockdevCreateOptions */ 3180 v = qobject_input_visitor_new_flat_confused(qdict, errp); 3181 if (!v) { 3182 ret = -EINVAL; 3183 goto finish; 3184 } 3185 3186 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 3187 visit_free(v); 3188 3189 if (local_err) { 3190 error_propagate(errp, local_err); 3191 ret = -EINVAL; 3192 goto finish; 3193 } 3194 3195 /* Silently round up size */ 3196 create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, 3197 BDRV_SECTOR_SIZE); 3198 3199 /* Create the qcow2 image (format layer) */ 3200 ret = qcow2_co_create(create_options, errp); 3201 if (ret < 0) { 3202 goto finish; 3203 } 3204 3205 ret = 0; 3206 finish: 3207 qobject_unref(qdict); 3208 bdrv_unref(bs); 3209 qapi_free_BlockdevCreateOptions(create_options); 3210 return ret; 3211 } 3212 3213 3214 static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) 3215 { 3216 int64_t nr; 3217 int res; 3218 3219 /* Clamp to image length, before checking status of underlying sectors */ 3220 if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { 3221 bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; 3222 } 3223 3224 if (!bytes) { 3225 return true; 3226 } 3227 res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); 3228 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes; 3229 } 3230 3231 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 3232 int64_t offset, int bytes, BdrvRequestFlags flags) 3233 { 3234 int ret; 3235 BDRVQcow2State *s = bs->opaque; 3236 3237 uint32_t head = offset % s->cluster_size; 3238 uint32_t tail = (offset + bytes) % s->cluster_size; 3239 3240 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); 3241 if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { 3242 tail = 0; 3243 } 3244 3245 if (head || tail) { 3246 uint64_t off; 3247 unsigned int nr; 3248 3249 assert(head + bytes <= s->cluster_size); 3250 3251 /* check whether remainder of cluster already reads as zero */ 3252 if (!(is_zero(bs, offset - head, head) && 3253 is_zero(bs, offset + bytes, 3254 tail ? s->cluster_size - tail : 0))) { 3255 return -ENOTSUP; 3256 } 3257 3258 qemu_co_mutex_lock(&s->lock); 3259 /* We can have new write after previous check */ 3260 offset = QEMU_ALIGN_DOWN(offset, s->cluster_size); 3261 bytes = s->cluster_size; 3262 nr = s->cluster_size; 3263 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 3264 if (ret != QCOW2_CLUSTER_UNALLOCATED && 3265 ret != QCOW2_CLUSTER_ZERO_PLAIN && 3266 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 3267 qemu_co_mutex_unlock(&s->lock); 3268 return -ENOTSUP; 3269 } 3270 } else { 3271 qemu_co_mutex_lock(&s->lock); 3272 } 3273 3274 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); 3275 3276 /* Whatever is left can use real zero clusters */ 3277 ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); 3278 qemu_co_mutex_unlock(&s->lock); 3279 3280 return ret; 3281 } 3282 3283 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 3284 int64_t offset, int bytes) 3285 { 3286 int ret; 3287 BDRVQcow2State *s = bs->opaque; 3288 3289 if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { 3290 assert(bytes < s->cluster_size); 3291 /* Ignore partial clusters, except for the special case of the 3292 * complete partial cluster at the end of an unaligned file */ 3293 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 3294 offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { 3295 return -ENOTSUP; 3296 } 3297 } 3298 3299 qemu_co_mutex_lock(&s->lock); 3300 ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, 3301 false); 3302 qemu_co_mutex_unlock(&s->lock); 3303 return ret; 3304 } 3305 3306 static int coroutine_fn 3307 qcow2_co_copy_range_from(BlockDriverState *bs, 3308 BdrvChild *src, uint64_t src_offset, 3309 BdrvChild *dst, uint64_t dst_offset, 3310 uint64_t bytes, BdrvRequestFlags read_flags, 3311 BdrvRequestFlags write_flags) 3312 { 3313 BDRVQcow2State *s = bs->opaque; 3314 int ret; 3315 unsigned int cur_bytes; /* number of bytes in current iteration */ 3316 BdrvChild *child = NULL; 3317 BdrvRequestFlags cur_write_flags; 3318 3319 assert(!bs->encrypted); 3320 qemu_co_mutex_lock(&s->lock); 3321 3322 while (bytes != 0) { 3323 uint64_t copy_offset = 0; 3324 /* prepare next request */ 3325 cur_bytes = MIN(bytes, INT_MAX); 3326 cur_write_flags = write_flags; 3327 3328 ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, ©_offset); 3329 if (ret < 0) { 3330 goto out; 3331 } 3332 3333 switch (ret) { 3334 case QCOW2_CLUSTER_UNALLOCATED: 3335 if (bs->backing && bs->backing->bs) { 3336 int64_t backing_length = bdrv_getlength(bs->backing->bs); 3337 if (src_offset >= backing_length) { 3338 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3339 } else { 3340 child = bs->backing; 3341 cur_bytes = MIN(cur_bytes, backing_length - src_offset); 3342 copy_offset = src_offset; 3343 } 3344 } else { 3345 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3346 } 3347 break; 3348 3349 case QCOW2_CLUSTER_ZERO_PLAIN: 3350 case QCOW2_CLUSTER_ZERO_ALLOC: 3351 cur_write_flags |= BDRV_REQ_ZERO_WRITE; 3352 break; 3353 3354 case QCOW2_CLUSTER_COMPRESSED: 3355 ret = -ENOTSUP; 3356 goto out; 3357 3358 case QCOW2_CLUSTER_NORMAL: 3359 child = bs->file; 3360 copy_offset += offset_into_cluster(s, src_offset); 3361 if ((copy_offset & 511) != 0) { 3362 ret = -EIO; 3363 goto out; 3364 } 3365 break; 3366 3367 default: 3368 abort(); 3369 } 3370 qemu_co_mutex_unlock(&s->lock); 3371 ret = bdrv_co_copy_range_from(child, 3372 copy_offset, 3373 dst, dst_offset, 3374 cur_bytes, read_flags, cur_write_flags); 3375 qemu_co_mutex_lock(&s->lock); 3376 if (ret < 0) { 3377 goto out; 3378 } 3379 3380 bytes -= cur_bytes; 3381 src_offset += cur_bytes; 3382 dst_offset += cur_bytes; 3383 } 3384 ret = 0; 3385 3386 out: 3387 qemu_co_mutex_unlock(&s->lock); 3388 return ret; 3389 } 3390 3391 static int coroutine_fn 3392 qcow2_co_copy_range_to(BlockDriverState *bs, 3393 BdrvChild *src, uint64_t src_offset, 3394 BdrvChild *dst, uint64_t dst_offset, 3395 uint64_t bytes, BdrvRequestFlags read_flags, 3396 BdrvRequestFlags write_flags) 3397 { 3398 BDRVQcow2State *s = bs->opaque; 3399 int offset_in_cluster; 3400 int ret; 3401 unsigned int cur_bytes; /* number of sectors in current iteration */ 3402 uint64_t cluster_offset; 3403 QCowL2Meta *l2meta = NULL; 3404 3405 assert(!bs->encrypted); 3406 3407 qemu_co_mutex_lock(&s->lock); 3408 3409 while (bytes != 0) { 3410 3411 l2meta = NULL; 3412 3413 offset_in_cluster = offset_into_cluster(s, dst_offset); 3414 cur_bytes = MIN(bytes, INT_MAX); 3415 3416 /* TODO: 3417 * If src->bs == dst->bs, we could simply copy by incrementing 3418 * the refcnt, without copying user data. 3419 * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ 3420 ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes, 3421 &cluster_offset, &l2meta); 3422 if (ret < 0) { 3423 goto fail; 3424 } 3425 3426 assert((cluster_offset & 511) == 0); 3427 3428 ret = qcow2_pre_write_overlap_check(bs, 0, 3429 cluster_offset + offset_in_cluster, cur_bytes); 3430 if (ret < 0) { 3431 goto fail; 3432 } 3433 3434 qemu_co_mutex_unlock(&s->lock); 3435 ret = bdrv_co_copy_range_to(src, src_offset, 3436 bs->file, 3437 cluster_offset + offset_in_cluster, 3438 cur_bytes, read_flags, write_flags); 3439 qemu_co_mutex_lock(&s->lock); 3440 if (ret < 0) { 3441 goto fail; 3442 } 3443 3444 ret = qcow2_handle_l2meta(bs, &l2meta, true); 3445 if (ret) { 3446 goto fail; 3447 } 3448 3449 bytes -= cur_bytes; 3450 src_offset += cur_bytes; 3451 dst_offset += cur_bytes; 3452 } 3453 ret = 0; 3454 3455 fail: 3456 qcow2_handle_l2meta(bs, &l2meta, false); 3457 3458 qemu_co_mutex_unlock(&s->lock); 3459 3460 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 3461 3462 return ret; 3463 } 3464 3465 static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, 3466 PreallocMode prealloc, Error **errp) 3467 { 3468 BDRVQcow2State *s = bs->opaque; 3469 uint64_t old_length; 3470 int64_t new_l1_size; 3471 int ret; 3472 QDict *options; 3473 3474 if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && 3475 prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) 3476 { 3477 error_setg(errp, "Unsupported preallocation mode '%s'", 3478 PreallocMode_str(prealloc)); 3479 return -ENOTSUP; 3480 } 3481 3482 if (offset & 511) { 3483 error_setg(errp, "The new size must be a multiple of 512"); 3484 return -EINVAL; 3485 } 3486 3487 qemu_co_mutex_lock(&s->lock); 3488 3489 /* cannot proceed if image has snapshots */ 3490 if (s->nb_snapshots) { 3491 error_setg(errp, "Can't resize an image which has snapshots"); 3492 ret = -ENOTSUP; 3493 goto fail; 3494 } 3495 3496 /* cannot proceed if image has bitmaps */ 3497 if (s->nb_bitmaps) { 3498 /* TODO: resize bitmaps in the image */ 3499 error_setg(errp, "Can't resize an image which has bitmaps"); 3500 ret = -ENOTSUP; 3501 goto fail; 3502 } 3503 3504 old_length = bs->total_sectors * BDRV_SECTOR_SIZE; 3505 new_l1_size = size_to_l1(s, offset); 3506 3507 if (offset < old_length) { 3508 int64_t last_cluster, old_file_size; 3509 if (prealloc != PREALLOC_MODE_OFF) { 3510 error_setg(errp, 3511 "Preallocation can't be used for shrinking an image"); 3512 ret = -EINVAL; 3513 goto fail; 3514 } 3515 3516 ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), 3517 old_length - ROUND_UP(offset, 3518 s->cluster_size), 3519 QCOW2_DISCARD_ALWAYS, true); 3520 if (ret < 0) { 3521 error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); 3522 goto fail; 3523 } 3524 3525 ret = qcow2_shrink_l1_table(bs, new_l1_size); 3526 if (ret < 0) { 3527 error_setg_errno(errp, -ret, 3528 "Failed to reduce the number of L2 tables"); 3529 goto fail; 3530 } 3531 3532 ret = qcow2_shrink_reftable(bs); 3533 if (ret < 0) { 3534 error_setg_errno(errp, -ret, 3535 "Failed to discard unused refblocks"); 3536 goto fail; 3537 } 3538 3539 old_file_size = bdrv_getlength(bs->file->bs); 3540 if (old_file_size < 0) { 3541 error_setg_errno(errp, -old_file_size, 3542 "Failed to inquire current file length"); 3543 ret = old_file_size; 3544 goto fail; 3545 } 3546 last_cluster = qcow2_get_last_cluster(bs, old_file_size); 3547 if (last_cluster < 0) { 3548 error_setg_errno(errp, -last_cluster, 3549 "Failed to find the last cluster"); 3550 ret = last_cluster; 3551 goto fail; 3552 } 3553 if ((last_cluster + 1) * s->cluster_size < old_file_size) { 3554 Error *local_err = NULL; 3555 3556 bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, 3557 PREALLOC_MODE_OFF, &local_err); 3558 if (local_err) { 3559 warn_reportf_err(local_err, 3560 "Failed to truncate the tail of the image: "); 3561 } 3562 } 3563 } else { 3564 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 3565 if (ret < 0) { 3566 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 3567 goto fail; 3568 } 3569 } 3570 3571 switch (prealloc) { 3572 case PREALLOC_MODE_OFF: 3573 break; 3574 3575 case PREALLOC_MODE_METADATA: 3576 ret = preallocate_co(bs, old_length, offset); 3577 if (ret < 0) { 3578 error_setg_errno(errp, -ret, "Preallocation failed"); 3579 goto fail; 3580 } 3581 break; 3582 3583 case PREALLOC_MODE_FALLOC: 3584 case PREALLOC_MODE_FULL: 3585 { 3586 int64_t allocation_start, host_offset, guest_offset; 3587 int64_t clusters_allocated; 3588 int64_t old_file_size, new_file_size; 3589 uint64_t nb_new_data_clusters, nb_new_l2_tables; 3590 3591 old_file_size = bdrv_getlength(bs->file->bs); 3592 if (old_file_size < 0) { 3593 error_setg_errno(errp, -old_file_size, 3594 "Failed to inquire current file length"); 3595 ret = old_file_size; 3596 goto fail; 3597 } 3598 old_file_size = ROUND_UP(old_file_size, s->cluster_size); 3599 3600 nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, 3601 s->cluster_size); 3602 3603 /* This is an overestimation; we will not actually allocate space for 3604 * these in the file but just make sure the new refcount structures are 3605 * able to cover them so we will not have to allocate new refblocks 3606 * while entering the data blocks in the potentially new L2 tables. 3607 * (We do not actually care where the L2 tables are placed. Maybe they 3608 * are already allocated or they can be placed somewhere before 3609 * @old_file_size. It does not matter because they will be fully 3610 * allocated automatically, so they do not need to be covered by the 3611 * preallocation. All that matters is that we will not have to allocate 3612 * new refcount structures for them.) */ 3613 nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, 3614 s->cluster_size / sizeof(uint64_t)); 3615 /* The cluster range may not be aligned to L2 boundaries, so add one L2 3616 * table for a potential head/tail */ 3617 nb_new_l2_tables++; 3618 3619 allocation_start = qcow2_refcount_area(bs, old_file_size, 3620 nb_new_data_clusters + 3621 nb_new_l2_tables, 3622 true, 0, 0); 3623 if (allocation_start < 0) { 3624 error_setg_errno(errp, -allocation_start, 3625 "Failed to resize refcount structures"); 3626 ret = allocation_start; 3627 goto fail; 3628 } 3629 3630 clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, 3631 nb_new_data_clusters); 3632 if (clusters_allocated < 0) { 3633 error_setg_errno(errp, -clusters_allocated, 3634 "Failed to allocate data clusters"); 3635 ret = clusters_allocated; 3636 goto fail; 3637 } 3638 3639 assert(clusters_allocated == nb_new_data_clusters); 3640 3641 /* Allocate the data area */ 3642 new_file_size = allocation_start + 3643 nb_new_data_clusters * s->cluster_size; 3644 ret = bdrv_co_truncate(bs->file, new_file_size, prealloc, errp); 3645 if (ret < 0) { 3646 error_prepend(errp, "Failed to resize underlying file: "); 3647 qcow2_free_clusters(bs, allocation_start, 3648 nb_new_data_clusters * s->cluster_size, 3649 QCOW2_DISCARD_OTHER); 3650 goto fail; 3651 } 3652 3653 /* Create the necessary L2 entries */ 3654 host_offset = allocation_start; 3655 guest_offset = old_length; 3656 while (nb_new_data_clusters) { 3657 int64_t nb_clusters = MIN( 3658 nb_new_data_clusters, 3659 s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); 3660 QCowL2Meta allocation = { 3661 .offset = guest_offset, 3662 .alloc_offset = host_offset, 3663 .nb_clusters = nb_clusters, 3664 }; 3665 qemu_co_queue_init(&allocation.dependent_requests); 3666 3667 ret = qcow2_alloc_cluster_link_l2(bs, &allocation); 3668 if (ret < 0) { 3669 error_setg_errno(errp, -ret, "Failed to update L2 tables"); 3670 qcow2_free_clusters(bs, host_offset, 3671 nb_new_data_clusters * s->cluster_size, 3672 QCOW2_DISCARD_OTHER); 3673 goto fail; 3674 } 3675 3676 guest_offset += nb_clusters * s->cluster_size; 3677 host_offset += nb_clusters * s->cluster_size; 3678 nb_new_data_clusters -= nb_clusters; 3679 } 3680 break; 3681 } 3682 3683 default: 3684 g_assert_not_reached(); 3685 } 3686 3687 if (prealloc != PREALLOC_MODE_OFF) { 3688 /* Flush metadata before actually changing the image size */ 3689 ret = qcow2_write_caches(bs); 3690 if (ret < 0) { 3691 error_setg_errno(errp, -ret, 3692 "Failed to flush the preallocated area to disk"); 3693 goto fail; 3694 } 3695 } 3696 3697 bs->total_sectors = offset / BDRV_SECTOR_SIZE; 3698 3699 /* write updated header.size */ 3700 offset = cpu_to_be64(offset); 3701 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 3702 &offset, sizeof(uint64_t)); 3703 if (ret < 0) { 3704 error_setg_errno(errp, -ret, "Failed to update the image size"); 3705 goto fail; 3706 } 3707 3708 s->l1_vm_state_index = new_l1_size; 3709 3710 /* Update cache sizes */ 3711 options = qdict_clone_shallow(bs->options); 3712 ret = qcow2_update_options(bs, options, s->flags, errp); 3713 qobject_unref(options); 3714 if (ret < 0) { 3715 goto fail; 3716 } 3717 ret = 0; 3718 fail: 3719 qemu_co_mutex_unlock(&s->lock); 3720 return ret; 3721 } 3722 3723 /* 3724 * qcow2_compress() 3725 * 3726 * @dest - destination buffer, @dest_size bytes 3727 * @src - source buffer, @src_size bytes 3728 * 3729 * Returns: compressed size on success 3730 * -1 destination buffer is not enough to store compressed data 3731 * -2 on any other error 3732 */ 3733 static ssize_t qcow2_compress(void *dest, size_t dest_size, 3734 const void *src, size_t src_size) 3735 { 3736 ssize_t ret; 3737 z_stream strm; 3738 3739 /* best compression, small window, no zlib header */ 3740 memset(&strm, 0, sizeof(strm)); 3741 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 3742 -12, 9, Z_DEFAULT_STRATEGY); 3743 if (ret != Z_OK) { 3744 return -2; 3745 } 3746 3747 /* strm.next_in is not const in old zlib versions, such as those used on 3748 * OpenBSD/NetBSD, so cast the const away */ 3749 strm.avail_in = src_size; 3750 strm.next_in = (void *) src; 3751 strm.avail_out = dest_size; 3752 strm.next_out = dest; 3753 3754 ret = deflate(&strm, Z_FINISH); 3755 if (ret == Z_STREAM_END) { 3756 ret = dest_size - strm.avail_out; 3757 } else { 3758 ret = (ret == Z_OK ? -1 : -2); 3759 } 3760 3761 deflateEnd(&strm); 3762 3763 return ret; 3764 } 3765 3766 /* 3767 * qcow2_decompress() 3768 * 3769 * Decompress some data (not more than @src_size bytes) to produce exactly 3770 * @dest_size bytes. 3771 * 3772 * @dest - destination buffer, @dest_size bytes 3773 * @src - source buffer, @src_size bytes 3774 * 3775 * Returns: 0 on success 3776 * -1 on fail 3777 */ 3778 static ssize_t qcow2_decompress(void *dest, size_t dest_size, 3779 const void *src, size_t src_size) 3780 { 3781 int ret = 0; 3782 z_stream strm; 3783 3784 memset(&strm, 0, sizeof(strm)); 3785 strm.avail_in = src_size; 3786 strm.next_in = (void *) src; 3787 strm.avail_out = dest_size; 3788 strm.next_out = dest; 3789 3790 ret = inflateInit2(&strm, -12); 3791 if (ret != Z_OK) { 3792 return -1; 3793 } 3794 3795 ret = inflate(&strm, Z_FINISH); 3796 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) { 3797 /* We approve Z_BUF_ERROR because we need @dest buffer to be filled, but 3798 * @src buffer may be processed partly (because in qcow2 we know size of 3799 * compressed data with precision of one sector) */ 3800 ret = -1; 3801 } 3802 3803 inflateEnd(&strm); 3804 3805 return ret; 3806 } 3807 3808 #define MAX_COMPRESS_THREADS 4 3809 3810 typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size, 3811 const void *src, size_t src_size); 3812 typedef struct Qcow2CompressData { 3813 void *dest; 3814 size_t dest_size; 3815 const void *src; 3816 size_t src_size; 3817 ssize_t ret; 3818 3819 Qcow2CompressFunc func; 3820 } Qcow2CompressData; 3821 3822 static int qcow2_compress_pool_func(void *opaque) 3823 { 3824 Qcow2CompressData *data = opaque; 3825 3826 data->ret = data->func(data->dest, data->dest_size, 3827 data->src, data->src_size); 3828 3829 return 0; 3830 } 3831 3832 static void qcow2_compress_complete(void *opaque, int ret) 3833 { 3834 qemu_coroutine_enter(opaque); 3835 } 3836 3837 static ssize_t coroutine_fn 3838 qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size, 3839 const void *src, size_t src_size, Qcow2CompressFunc func) 3840 { 3841 BDRVQcow2State *s = bs->opaque; 3842 BlockAIOCB *acb; 3843 ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs)); 3844 Qcow2CompressData arg = { 3845 .dest = dest, 3846 .dest_size = dest_size, 3847 .src = src, 3848 .src_size = src_size, 3849 .func = func, 3850 }; 3851 3852 while (s->nb_compress_threads >= MAX_COMPRESS_THREADS) { 3853 qemu_co_queue_wait(&s->compress_wait_queue, NULL); 3854 } 3855 3856 s->nb_compress_threads++; 3857 acb = thread_pool_submit_aio(pool, qcow2_compress_pool_func, &arg, 3858 qcow2_compress_complete, 3859 qemu_coroutine_self()); 3860 3861 if (!acb) { 3862 s->nb_compress_threads--; 3863 return -EINVAL; 3864 } 3865 qemu_coroutine_yield(); 3866 s->nb_compress_threads--; 3867 qemu_co_queue_next(&s->compress_wait_queue); 3868 3869 return arg.ret; 3870 } 3871 3872 static ssize_t coroutine_fn 3873 qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size, 3874 const void *src, size_t src_size) 3875 { 3876 return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, 3877 qcow2_compress); 3878 } 3879 3880 static ssize_t coroutine_fn 3881 qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size, 3882 const void *src, size_t src_size) 3883 { 3884 return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, 3885 qcow2_decompress); 3886 } 3887 3888 /* XXX: put compressed sectors first, then all the cluster aligned 3889 tables to avoid losing bytes in alignment */ 3890 static coroutine_fn int 3891 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 3892 uint64_t bytes, QEMUIOVector *qiov) 3893 { 3894 BDRVQcow2State *s = bs->opaque; 3895 QEMUIOVector hd_qiov; 3896 struct iovec iov; 3897 int ret; 3898 size_t out_len; 3899 uint8_t *buf, *out_buf; 3900 int64_t cluster_offset; 3901 3902 if (bytes == 0) { 3903 /* align end of file to a sector boundary to ease reading with 3904 sector based I/Os */ 3905 cluster_offset = bdrv_getlength(bs->file->bs); 3906 if (cluster_offset < 0) { 3907 return cluster_offset; 3908 } 3909 return bdrv_co_truncate(bs->file, cluster_offset, PREALLOC_MODE_OFF, 3910 NULL); 3911 } 3912 3913 if (offset_into_cluster(s, offset)) { 3914 return -EINVAL; 3915 } 3916 3917 buf = qemu_blockalign(bs, s->cluster_size); 3918 if (bytes != s->cluster_size) { 3919 if (bytes > s->cluster_size || 3920 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 3921 { 3922 qemu_vfree(buf); 3923 return -EINVAL; 3924 } 3925 /* Zero-pad last write if image size is not cluster aligned */ 3926 memset(buf + bytes, 0, s->cluster_size - bytes); 3927 } 3928 qemu_iovec_to_buf(qiov, 0, buf, bytes); 3929 3930 out_buf = g_malloc(s->cluster_size); 3931 3932 out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1, 3933 buf, s->cluster_size); 3934 if (out_len == -2) { 3935 ret = -EINVAL; 3936 goto fail; 3937 } else if (out_len == -1) { 3938 /* could not compress: write normal cluster */ 3939 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 3940 if (ret < 0) { 3941 goto fail; 3942 } 3943 goto success; 3944 } 3945 3946 qemu_co_mutex_lock(&s->lock); 3947 cluster_offset = 3948 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); 3949 if (!cluster_offset) { 3950 qemu_co_mutex_unlock(&s->lock); 3951 ret = -EIO; 3952 goto fail; 3953 } 3954 cluster_offset &= s->cluster_offset_mask; 3955 3956 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 3957 qemu_co_mutex_unlock(&s->lock); 3958 if (ret < 0) { 3959 goto fail; 3960 } 3961 3962 iov = (struct iovec) { 3963 .iov_base = out_buf, 3964 .iov_len = out_len, 3965 }; 3966 qemu_iovec_init_external(&hd_qiov, &iov, 1); 3967 3968 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 3969 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 3970 if (ret < 0) { 3971 goto fail; 3972 } 3973 success: 3974 ret = 0; 3975 fail: 3976 qemu_vfree(buf); 3977 g_free(out_buf); 3978 return ret; 3979 } 3980 3981 static int coroutine_fn 3982 qcow2_co_preadv_compressed(BlockDriverState *bs, 3983 uint64_t file_cluster_offset, 3984 uint64_t offset, 3985 uint64_t bytes, 3986 QEMUIOVector *qiov) 3987 { 3988 BDRVQcow2State *s = bs->opaque; 3989 int ret = 0, csize, nb_csectors; 3990 uint64_t coffset; 3991 uint8_t *buf, *out_buf; 3992 struct iovec iov; 3993 QEMUIOVector local_qiov; 3994 int offset_in_cluster = offset_into_cluster(s, offset); 3995 3996 coffset = file_cluster_offset & s->cluster_offset_mask; 3997 nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1; 3998 csize = nb_csectors * 512 - (coffset & 511); 3999 4000 buf = g_try_malloc(csize); 4001 if (!buf) { 4002 return -ENOMEM; 4003 } 4004 iov.iov_base = buf; 4005 iov.iov_len = csize; 4006 qemu_iovec_init_external(&local_qiov, &iov, 1); 4007 4008 out_buf = qemu_blockalign(bs, s->cluster_size); 4009 4010 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 4011 ret = bdrv_co_preadv(bs->file, coffset, csize, &local_qiov, 0); 4012 if (ret < 0) { 4013 goto fail; 4014 } 4015 4016 if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) { 4017 ret = -EIO; 4018 goto fail; 4019 } 4020 4021 qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes); 4022 4023 fail: 4024 qemu_vfree(out_buf); 4025 g_free(buf); 4026 4027 return ret; 4028 } 4029 4030 static int make_completely_empty(BlockDriverState *bs) 4031 { 4032 BDRVQcow2State *s = bs->opaque; 4033 Error *local_err = NULL; 4034 int ret, l1_clusters; 4035 int64_t offset; 4036 uint64_t *new_reftable = NULL; 4037 uint64_t rt_entry, l1_size2; 4038 struct { 4039 uint64_t l1_offset; 4040 uint64_t reftable_offset; 4041 uint32_t reftable_clusters; 4042 } QEMU_PACKED l1_ofs_rt_ofs_cls; 4043 4044 ret = qcow2_cache_empty(bs, s->l2_table_cache); 4045 if (ret < 0) { 4046 goto fail; 4047 } 4048 4049 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 4050 if (ret < 0) { 4051 goto fail; 4052 } 4053 4054 /* Refcounts will be broken utterly */ 4055 ret = qcow2_mark_dirty(bs); 4056 if (ret < 0) { 4057 goto fail; 4058 } 4059 4060 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4061 4062 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4063 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 4064 4065 /* After this call, neither the in-memory nor the on-disk refcount 4066 * information accurately describe the actual references */ 4067 4068 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 4069 l1_clusters * s->cluster_size, 0); 4070 if (ret < 0) { 4071 goto fail_broken_refcounts; 4072 } 4073 memset(s->l1_table, 0, l1_size2); 4074 4075 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 4076 4077 /* Overwrite enough clusters at the beginning of the sectors to place 4078 * the refcount table, a refcount block and the L1 table in; this may 4079 * overwrite parts of the existing refcount and L1 table, which is not 4080 * an issue because the dirty flag is set, complete data loss is in fact 4081 * desired and partial data loss is consequently fine as well */ 4082 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 4083 (2 + l1_clusters) * s->cluster_size, 0); 4084 /* This call (even if it failed overall) may have overwritten on-disk 4085 * refcount structures; in that case, the in-memory refcount information 4086 * will probably differ from the on-disk information which makes the BDS 4087 * unusable */ 4088 if (ret < 0) { 4089 goto fail_broken_refcounts; 4090 } 4091 4092 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 4093 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 4094 4095 /* "Create" an empty reftable (one cluster) directly after the image 4096 * header and an empty L1 table three clusters after the image header; 4097 * the cluster between those two will be used as the first refblock */ 4098 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 4099 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 4100 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 4101 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 4102 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 4103 if (ret < 0) { 4104 goto fail_broken_refcounts; 4105 } 4106 4107 s->l1_table_offset = 3 * s->cluster_size; 4108 4109 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 4110 if (!new_reftable) { 4111 ret = -ENOMEM; 4112 goto fail_broken_refcounts; 4113 } 4114 4115 s->refcount_table_offset = s->cluster_size; 4116 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 4117 s->max_refcount_table_index = 0; 4118 4119 g_free(s->refcount_table); 4120 s->refcount_table = new_reftable; 4121 new_reftable = NULL; 4122 4123 /* Now the in-memory refcount information again corresponds to the on-disk 4124 * information (reftable is empty and no refblocks (the refblock cache is 4125 * empty)); however, this means some clusters (e.g. the image header) are 4126 * referenced, but not refcounted, but the normal qcow2 code assumes that 4127 * the in-memory information is always correct */ 4128 4129 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 4130 4131 /* Enter the first refblock into the reftable */ 4132 rt_entry = cpu_to_be64(2 * s->cluster_size); 4133 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 4134 &rt_entry, sizeof(rt_entry)); 4135 if (ret < 0) { 4136 goto fail_broken_refcounts; 4137 } 4138 s->refcount_table[0] = 2 * s->cluster_size; 4139 4140 s->free_cluster_index = 0; 4141 assert(3 + l1_clusters <= s->refcount_block_size); 4142 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 4143 if (offset < 0) { 4144 ret = offset; 4145 goto fail_broken_refcounts; 4146 } else if (offset > 0) { 4147 error_report("First cluster in emptied image is in use"); 4148 abort(); 4149 } 4150 4151 /* Now finally the in-memory information corresponds to the on-disk 4152 * structures and is correct */ 4153 ret = qcow2_mark_clean(bs); 4154 if (ret < 0) { 4155 goto fail; 4156 } 4157 4158 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 4159 PREALLOC_MODE_OFF, &local_err); 4160 if (ret < 0) { 4161 error_report_err(local_err); 4162 goto fail; 4163 } 4164 4165 return 0; 4166 4167 fail_broken_refcounts: 4168 /* The BDS is unusable at this point. If we wanted to make it usable, we 4169 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 4170 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 4171 * again. However, because the functions which could have caused this error 4172 * path to be taken are used by those functions as well, it's very likely 4173 * that that sequence will fail as well. Therefore, just eject the BDS. */ 4174 bs->drv = NULL; 4175 4176 fail: 4177 g_free(new_reftable); 4178 return ret; 4179 } 4180 4181 static int qcow2_make_empty(BlockDriverState *bs) 4182 { 4183 BDRVQcow2State *s = bs->opaque; 4184 uint64_t offset, end_offset; 4185 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 4186 int l1_clusters, ret = 0; 4187 4188 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 4189 4190 if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && 4191 3 + l1_clusters <= s->refcount_block_size && 4192 s->crypt_method_header != QCOW_CRYPT_LUKS) { 4193 /* The following function only works for qcow2 v3 images (it 4194 * requires the dirty flag) and only as long as there are no 4195 * features that reserve extra clusters (such as snapshots, 4196 * LUKS header, or persistent bitmaps), because it completely 4197 * empties the image. Furthermore, the L1 table and three 4198 * additional clusters (image header, refcount table, one 4199 * refcount block) have to fit inside one refcount block. */ 4200 return make_completely_empty(bs); 4201 } 4202 4203 /* This fallback code simply discards every active cluster; this is slow, 4204 * but works in all cases */ 4205 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 4206 for (offset = 0; offset < end_offset; offset += step) { 4207 /* As this function is generally used after committing an external 4208 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 4209 * default action for this kind of discard is to pass the discard, 4210 * which will ideally result in an actually smaller image file, as 4211 * is probably desired. */ 4212 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 4213 QCOW2_DISCARD_SNAPSHOT, true); 4214 if (ret < 0) { 4215 break; 4216 } 4217 } 4218 4219 return ret; 4220 } 4221 4222 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 4223 { 4224 BDRVQcow2State *s = bs->opaque; 4225 int ret; 4226 4227 qemu_co_mutex_lock(&s->lock); 4228 ret = qcow2_write_caches(bs); 4229 qemu_co_mutex_unlock(&s->lock); 4230 4231 return ret; 4232 } 4233 4234 static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, 4235 Error **errp) 4236 { 4237 Error *local_err = NULL; 4238 BlockMeasureInfo *info; 4239 uint64_t required = 0; /* bytes that contribute to required size */ 4240 uint64_t virtual_size; /* disk size as seen by guest */ 4241 uint64_t refcount_bits; 4242 uint64_t l2_tables; 4243 size_t cluster_size; 4244 int version; 4245 char *optstr; 4246 PreallocMode prealloc; 4247 bool has_backing_file; 4248 4249 /* Parse image creation options */ 4250 cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); 4251 if (local_err) { 4252 goto err; 4253 } 4254 4255 version = qcow2_opt_get_version_del(opts, &local_err); 4256 if (local_err) { 4257 goto err; 4258 } 4259 4260 refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); 4261 if (local_err) { 4262 goto err; 4263 } 4264 4265 optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 4266 prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, 4267 PREALLOC_MODE_OFF, &local_err); 4268 g_free(optstr); 4269 if (local_err) { 4270 goto err; 4271 } 4272 4273 optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 4274 has_backing_file = !!optstr; 4275 g_free(optstr); 4276 4277 virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 4278 virtual_size = ROUND_UP(virtual_size, cluster_size); 4279 4280 /* Check that virtual disk size is valid */ 4281 l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, 4282 cluster_size / sizeof(uint64_t)); 4283 if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { 4284 error_setg(&local_err, "The image size is too large " 4285 "(try using a larger cluster size)"); 4286 goto err; 4287 } 4288 4289 /* Account for input image */ 4290 if (in_bs) { 4291 int64_t ssize = bdrv_getlength(in_bs); 4292 if (ssize < 0) { 4293 error_setg_errno(&local_err, -ssize, 4294 "Unable to get image virtual_size"); 4295 goto err; 4296 } 4297 4298 virtual_size = ROUND_UP(ssize, cluster_size); 4299 4300 if (has_backing_file) { 4301 /* We don't how much of the backing chain is shared by the input 4302 * image and the new image file. In the worst case the new image's 4303 * backing file has nothing in common with the input image. Be 4304 * conservative and assume all clusters need to be written. 4305 */ 4306 required = virtual_size; 4307 } else { 4308 int64_t offset; 4309 int64_t pnum = 0; 4310 4311 for (offset = 0; offset < ssize; offset += pnum) { 4312 int ret; 4313 4314 ret = bdrv_block_status_above(in_bs, NULL, offset, 4315 ssize - offset, &pnum, NULL, 4316 NULL); 4317 if (ret < 0) { 4318 error_setg_errno(&local_err, -ret, 4319 "Unable to get block status"); 4320 goto err; 4321 } 4322 4323 if (ret & BDRV_BLOCK_ZERO) { 4324 /* Skip zero regions (safe with no backing file) */ 4325 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == 4326 (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { 4327 /* Extend pnum to end of cluster for next iteration */ 4328 pnum = ROUND_UP(offset + pnum, cluster_size) - offset; 4329 4330 /* Count clusters we've seen */ 4331 required += offset % cluster_size + pnum; 4332 } 4333 } 4334 } 4335 } 4336 4337 /* Take into account preallocation. Nothing special is needed for 4338 * PREALLOC_MODE_METADATA since metadata is always counted. 4339 */ 4340 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 4341 required = virtual_size; 4342 } 4343 4344 info = g_new(BlockMeasureInfo, 1); 4345 info->fully_allocated = 4346 qcow2_calc_prealloc_size(virtual_size, cluster_size, 4347 ctz32(refcount_bits)); 4348 4349 /* Remove data clusters that are not required. This overestimates the 4350 * required size because metadata needed for the fully allocated file is 4351 * still counted. 4352 */ 4353 info->required = info->fully_allocated - virtual_size + required; 4354 return info; 4355 4356 err: 4357 error_propagate(errp, local_err); 4358 return NULL; 4359 } 4360 4361 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4362 { 4363 BDRVQcow2State *s = bs->opaque; 4364 bdi->unallocated_blocks_are_zero = true; 4365 bdi->cluster_size = s->cluster_size; 4366 bdi->vm_state_offset = qcow2_vm_state_offset(s); 4367 return 0; 4368 } 4369 4370 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 4371 { 4372 BDRVQcow2State *s = bs->opaque; 4373 ImageInfoSpecific *spec_info; 4374 QCryptoBlockInfo *encrypt_info = NULL; 4375 4376 if (s->crypto != NULL) { 4377 encrypt_info = qcrypto_block_get_info(s->crypto, &error_abort); 4378 } 4379 4380 spec_info = g_new(ImageInfoSpecific, 1); 4381 *spec_info = (ImageInfoSpecific){ 4382 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 4383 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 4384 }; 4385 if (s->qcow_version == 2) { 4386 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4387 .compat = g_strdup("0.10"), 4388 .refcount_bits = s->refcount_bits, 4389 }; 4390 } else if (s->qcow_version == 3) { 4391 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 4392 .compat = g_strdup("1.1"), 4393 .lazy_refcounts = s->compatible_features & 4394 QCOW2_COMPAT_LAZY_REFCOUNTS, 4395 .has_lazy_refcounts = true, 4396 .corrupt = s->incompatible_features & 4397 QCOW2_INCOMPAT_CORRUPT, 4398 .has_corrupt = true, 4399 .refcount_bits = s->refcount_bits, 4400 }; 4401 } else { 4402 /* if this assertion fails, this probably means a new version was 4403 * added without having it covered here */ 4404 assert(false); 4405 } 4406 4407 if (encrypt_info) { 4408 ImageInfoSpecificQCow2Encryption *qencrypt = 4409 g_new(ImageInfoSpecificQCow2Encryption, 1); 4410 switch (encrypt_info->format) { 4411 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 4412 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; 4413 break; 4414 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 4415 qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; 4416 qencrypt->u.luks = encrypt_info->u.luks; 4417 break; 4418 default: 4419 abort(); 4420 } 4421 /* Since we did shallow copy above, erase any pointers 4422 * in the original info */ 4423 memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); 4424 qapi_free_QCryptoBlockInfo(encrypt_info); 4425 4426 spec_info->u.qcow2.data->has_encrypt = true; 4427 spec_info->u.qcow2.data->encrypt = qencrypt; 4428 } 4429 4430 return spec_info; 4431 } 4432 4433 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4434 int64_t pos) 4435 { 4436 BDRVQcow2State *s = bs->opaque; 4437 4438 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 4439 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 4440 qiov->size, qiov, 0); 4441 } 4442 4443 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 4444 int64_t pos) 4445 { 4446 BDRVQcow2State *s = bs->opaque; 4447 4448 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 4449 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 4450 qiov->size, qiov, 0); 4451 } 4452 4453 /* 4454 * Downgrades an image's version. To achieve this, any incompatible features 4455 * have to be removed. 4456 */ 4457 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 4458 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 4459 Error **errp) 4460 { 4461 BDRVQcow2State *s = bs->opaque; 4462 int current_version = s->qcow_version; 4463 int ret; 4464 4465 /* This is qcow2_downgrade(), not qcow2_upgrade() */ 4466 assert(target_version < current_version); 4467 4468 /* There are no other versions (now) that you can downgrade to */ 4469 assert(target_version == 2); 4470 4471 if (s->refcount_order != 4) { 4472 error_setg(errp, "compat=0.10 requires refcount_bits=16"); 4473 return -ENOTSUP; 4474 } 4475 4476 /* clear incompatible features */ 4477 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 4478 ret = qcow2_mark_clean(bs); 4479 if (ret < 0) { 4480 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4481 return ret; 4482 } 4483 } 4484 4485 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 4486 * the first place; if that happens nonetheless, returning -ENOTSUP is the 4487 * best thing to do anyway */ 4488 4489 if (s->incompatible_features) { 4490 error_setg(errp, "Cannot downgrade an image with incompatible features " 4491 "%#" PRIx64 " set", s->incompatible_features); 4492 return -ENOTSUP; 4493 } 4494 4495 /* since we can ignore compatible features, we can set them to 0 as well */ 4496 s->compatible_features = 0; 4497 /* if lazy refcounts have been used, they have already been fixed through 4498 * clearing the dirty flag */ 4499 4500 /* clearing autoclear features is trivial */ 4501 s->autoclear_features = 0; 4502 4503 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 4504 if (ret < 0) { 4505 error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); 4506 return ret; 4507 } 4508 4509 s->qcow_version = target_version; 4510 ret = qcow2_update_header(bs); 4511 if (ret < 0) { 4512 s->qcow_version = current_version; 4513 error_setg_errno(errp, -ret, "Failed to update the image header"); 4514 return ret; 4515 } 4516 return 0; 4517 } 4518 4519 typedef enum Qcow2AmendOperation { 4520 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 4521 * statically initialized to so that the helper CB can discern the first 4522 * invocation from an operation change */ 4523 QCOW2_NO_OPERATION = 0, 4524 4525 QCOW2_CHANGING_REFCOUNT_ORDER, 4526 QCOW2_DOWNGRADING, 4527 } Qcow2AmendOperation; 4528 4529 typedef struct Qcow2AmendHelperCBInfo { 4530 /* The code coordinating the amend operations should only modify 4531 * these four fields; the rest will be managed by the CB */ 4532 BlockDriverAmendStatusCB *original_status_cb; 4533 void *original_cb_opaque; 4534 4535 Qcow2AmendOperation current_operation; 4536 4537 /* Total number of operations to perform (only set once) */ 4538 int total_operations; 4539 4540 /* The following fields are managed by the CB */ 4541 4542 /* Number of operations completed */ 4543 int operations_completed; 4544 4545 /* Cumulative offset of all completed operations */ 4546 int64_t offset_completed; 4547 4548 Qcow2AmendOperation last_operation; 4549 int64_t last_work_size; 4550 } Qcow2AmendHelperCBInfo; 4551 4552 static void qcow2_amend_helper_cb(BlockDriverState *bs, 4553 int64_t operation_offset, 4554 int64_t operation_work_size, void *opaque) 4555 { 4556 Qcow2AmendHelperCBInfo *info = opaque; 4557 int64_t current_work_size; 4558 int64_t projected_work_size; 4559 4560 if (info->current_operation != info->last_operation) { 4561 if (info->last_operation != QCOW2_NO_OPERATION) { 4562 info->offset_completed += info->last_work_size; 4563 info->operations_completed++; 4564 } 4565 4566 info->last_operation = info->current_operation; 4567 } 4568 4569 assert(info->total_operations > 0); 4570 assert(info->operations_completed < info->total_operations); 4571 4572 info->last_work_size = operation_work_size; 4573 4574 current_work_size = info->offset_completed + operation_work_size; 4575 4576 /* current_work_size is the total work size for (operations_completed + 1) 4577 * operations (which includes this one), so multiply it by the number of 4578 * operations not covered and divide it by the number of operations 4579 * covered to get a projection for the operations not covered */ 4580 projected_work_size = current_work_size * (info->total_operations - 4581 info->operations_completed - 1) 4582 / (info->operations_completed + 1); 4583 4584 info->original_status_cb(bs, info->offset_completed + operation_offset, 4585 current_work_size + projected_work_size, 4586 info->original_cb_opaque); 4587 } 4588 4589 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 4590 BlockDriverAmendStatusCB *status_cb, 4591 void *cb_opaque, 4592 Error **errp) 4593 { 4594 BDRVQcow2State *s = bs->opaque; 4595 int old_version = s->qcow_version, new_version = old_version; 4596 uint64_t new_size = 0; 4597 const char *backing_file = NULL, *backing_format = NULL; 4598 bool lazy_refcounts = s->use_lazy_refcounts; 4599 const char *compat = NULL; 4600 uint64_t cluster_size = s->cluster_size; 4601 bool encrypt; 4602 int encformat; 4603 int refcount_bits = s->refcount_bits; 4604 int ret; 4605 QemuOptDesc *desc = opts->list->desc; 4606 Qcow2AmendHelperCBInfo helper_cb_info; 4607 4608 while (desc && desc->name) { 4609 if (!qemu_opt_find(opts, desc->name)) { 4610 /* only change explicitly defined options */ 4611 desc++; 4612 continue; 4613 } 4614 4615 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 4616 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 4617 if (!compat) { 4618 /* preserve default */ 4619 } else if (!strcmp(compat, "0.10")) { 4620 new_version = 2; 4621 } else if (!strcmp(compat, "1.1")) { 4622 new_version = 3; 4623 } else { 4624 error_setg(errp, "Unknown compatibility level %s", compat); 4625 return -EINVAL; 4626 } 4627 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 4628 error_setg(errp, "Cannot change preallocation mode"); 4629 return -ENOTSUP; 4630 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 4631 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4632 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 4633 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4634 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 4635 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4636 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 4637 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 4638 !!s->crypto); 4639 4640 if (encrypt != !!s->crypto) { 4641 error_setg(errp, 4642 "Changing the encryption flag is not supported"); 4643 return -ENOTSUP; 4644 } 4645 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { 4646 encformat = qcow2_crypt_method_from_format( 4647 qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); 4648 4649 if (encformat != s->crypt_method_header) { 4650 error_setg(errp, 4651 "Changing the encryption format is not supported"); 4652 return -ENOTSUP; 4653 } 4654 } else if (g_str_has_prefix(desc->name, "encrypt.")) { 4655 error_setg(errp, 4656 "Changing the encryption parameters is not supported"); 4657 return -ENOTSUP; 4658 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 4659 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 4660 cluster_size); 4661 if (cluster_size != s->cluster_size) { 4662 error_setg(errp, "Changing the cluster size is not supported"); 4663 return -ENOTSUP; 4664 } 4665 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 4666 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 4667 lazy_refcounts); 4668 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 4669 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 4670 refcount_bits); 4671 4672 if (refcount_bits <= 0 || refcount_bits > 64 || 4673 !is_power_of_2(refcount_bits)) 4674 { 4675 error_setg(errp, "Refcount width must be a power of two and " 4676 "may not exceed 64 bits"); 4677 return -EINVAL; 4678 } 4679 } else { 4680 /* if this point is reached, this probably means a new option was 4681 * added without having it covered here */ 4682 abort(); 4683 } 4684 4685 desc++; 4686 } 4687 4688 helper_cb_info = (Qcow2AmendHelperCBInfo){ 4689 .original_status_cb = status_cb, 4690 .original_cb_opaque = cb_opaque, 4691 .total_operations = (new_version < old_version) 4692 + (s->refcount_bits != refcount_bits) 4693 }; 4694 4695 /* Upgrade first (some features may require compat=1.1) */ 4696 if (new_version > old_version) { 4697 s->qcow_version = new_version; 4698 ret = qcow2_update_header(bs); 4699 if (ret < 0) { 4700 s->qcow_version = old_version; 4701 error_setg_errno(errp, -ret, "Failed to update the image header"); 4702 return ret; 4703 } 4704 } 4705 4706 if (s->refcount_bits != refcount_bits) { 4707 int refcount_order = ctz32(refcount_bits); 4708 4709 if (new_version < 3 && refcount_bits != 16) { 4710 error_setg(errp, "Refcount widths other than 16 bits require " 4711 "compatibility level 1.1 or above (use compat=1.1 or " 4712 "greater)"); 4713 return -EINVAL; 4714 } 4715 4716 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 4717 ret = qcow2_change_refcount_order(bs, refcount_order, 4718 &qcow2_amend_helper_cb, 4719 &helper_cb_info, errp); 4720 if (ret < 0) { 4721 return ret; 4722 } 4723 } 4724 4725 if (backing_file || backing_format) { 4726 ret = qcow2_change_backing_file(bs, 4727 backing_file ?: s->image_backing_file, 4728 backing_format ?: s->image_backing_format); 4729 if (ret < 0) { 4730 error_setg_errno(errp, -ret, "Failed to change the backing file"); 4731 return ret; 4732 } 4733 } 4734 4735 if (s->use_lazy_refcounts != lazy_refcounts) { 4736 if (lazy_refcounts) { 4737 if (new_version < 3) { 4738 error_setg(errp, "Lazy refcounts only supported with " 4739 "compatibility level 1.1 and above (use compat=1.1 " 4740 "or greater)"); 4741 return -EINVAL; 4742 } 4743 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4744 ret = qcow2_update_header(bs); 4745 if (ret < 0) { 4746 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4747 error_setg_errno(errp, -ret, "Failed to update the image header"); 4748 return ret; 4749 } 4750 s->use_lazy_refcounts = true; 4751 } else { 4752 /* make image clean first */ 4753 ret = qcow2_mark_clean(bs); 4754 if (ret < 0) { 4755 error_setg_errno(errp, -ret, "Failed to make the image clean"); 4756 return ret; 4757 } 4758 /* now disallow lazy refcounts */ 4759 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 4760 ret = qcow2_update_header(bs); 4761 if (ret < 0) { 4762 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 4763 error_setg_errno(errp, -ret, "Failed to update the image header"); 4764 return ret; 4765 } 4766 s->use_lazy_refcounts = false; 4767 } 4768 } 4769 4770 if (new_size) { 4771 BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); 4772 ret = blk_insert_bs(blk, bs, errp); 4773 if (ret < 0) { 4774 blk_unref(blk); 4775 return ret; 4776 } 4777 4778 ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp); 4779 blk_unref(blk); 4780 if (ret < 0) { 4781 return ret; 4782 } 4783 } 4784 4785 /* Downgrade last (so unsupported features can be removed before) */ 4786 if (new_version < old_version) { 4787 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 4788 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 4789 &helper_cb_info, errp); 4790 if (ret < 0) { 4791 return ret; 4792 } 4793 } 4794 4795 return 0; 4796 } 4797 4798 /* 4799 * If offset or size are negative, respectively, they will not be included in 4800 * the BLOCK_IMAGE_CORRUPTED event emitted. 4801 * fatal will be ignored for read-only BDS; corruptions found there will always 4802 * be considered non-fatal. 4803 */ 4804 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 4805 int64_t size, const char *message_format, ...) 4806 { 4807 BDRVQcow2State *s = bs->opaque; 4808 const char *node_name; 4809 char *message; 4810 va_list ap; 4811 4812 fatal = fatal && bdrv_is_writable(bs); 4813 4814 if (s->signaled_corruption && 4815 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 4816 { 4817 return; 4818 } 4819 4820 va_start(ap, message_format); 4821 message = g_strdup_vprintf(message_format, ap); 4822 va_end(ap); 4823 4824 if (fatal) { 4825 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 4826 "corruption events will be suppressed\n", message); 4827 } else { 4828 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 4829 "corruption events will be suppressed\n", message); 4830 } 4831 4832 node_name = bdrv_get_node_name(bs); 4833 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 4834 *node_name != '\0', node_name, 4835 message, offset >= 0, offset, 4836 size >= 0, size, 4837 fatal); 4838 g_free(message); 4839 4840 if (fatal) { 4841 qcow2_mark_corrupt(bs); 4842 bs->drv = NULL; /* make BDS unusable */ 4843 } 4844 4845 s->signaled_corruption = true; 4846 } 4847 4848 static QemuOptsList qcow2_create_opts = { 4849 .name = "qcow2-create-opts", 4850 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 4851 .desc = { 4852 { 4853 .name = BLOCK_OPT_SIZE, 4854 .type = QEMU_OPT_SIZE, 4855 .help = "Virtual disk size" 4856 }, 4857 { 4858 .name = BLOCK_OPT_COMPAT_LEVEL, 4859 .type = QEMU_OPT_STRING, 4860 .help = "Compatibility level (0.10 or 1.1)" 4861 }, 4862 { 4863 .name = BLOCK_OPT_BACKING_FILE, 4864 .type = QEMU_OPT_STRING, 4865 .help = "File name of a base image" 4866 }, 4867 { 4868 .name = BLOCK_OPT_BACKING_FMT, 4869 .type = QEMU_OPT_STRING, 4870 .help = "Image format of the base image" 4871 }, 4872 { 4873 .name = BLOCK_OPT_ENCRYPT, 4874 .type = QEMU_OPT_BOOL, 4875 .help = "Encrypt the image with format 'aes'. (Deprecated " 4876 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 4877 }, 4878 { 4879 .name = BLOCK_OPT_ENCRYPT_FORMAT, 4880 .type = QEMU_OPT_STRING, 4881 .help = "Encrypt the image, format choices: 'aes', 'luks'", 4882 }, 4883 BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", 4884 "ID of secret providing qcow AES key or LUKS passphrase"), 4885 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), 4886 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), 4887 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), 4888 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), 4889 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), 4890 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), 4891 { 4892 .name = BLOCK_OPT_CLUSTER_SIZE, 4893 .type = QEMU_OPT_SIZE, 4894 .help = "qcow2 cluster size", 4895 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 4896 }, 4897 { 4898 .name = BLOCK_OPT_PREALLOC, 4899 .type = QEMU_OPT_STRING, 4900 .help = "Preallocation mode (allowed values: off, metadata, " 4901 "falloc, full)" 4902 }, 4903 { 4904 .name = BLOCK_OPT_LAZY_REFCOUNTS, 4905 .type = QEMU_OPT_BOOL, 4906 .help = "Postpone refcount updates", 4907 .def_value_str = "off" 4908 }, 4909 { 4910 .name = BLOCK_OPT_REFCOUNT_BITS, 4911 .type = QEMU_OPT_NUMBER, 4912 .help = "Width of a reference count entry in bits", 4913 .def_value_str = "16" 4914 }, 4915 { /* end of list */ } 4916 } 4917 }; 4918 4919 BlockDriver bdrv_qcow2 = { 4920 .format_name = "qcow2", 4921 .instance_size = sizeof(BDRVQcow2State), 4922 .bdrv_probe = qcow2_probe, 4923 .bdrv_open = qcow2_open, 4924 .bdrv_close = qcow2_close, 4925 .bdrv_reopen_prepare = qcow2_reopen_prepare, 4926 .bdrv_reopen_commit = qcow2_reopen_commit, 4927 .bdrv_reopen_abort = qcow2_reopen_abort, 4928 .bdrv_join_options = qcow2_join_options, 4929 .bdrv_child_perm = bdrv_format_default_perms, 4930 .bdrv_co_create_opts = qcow2_co_create_opts, 4931 .bdrv_co_create = qcow2_co_create, 4932 .bdrv_has_zero_init = bdrv_has_zero_init_1, 4933 .bdrv_co_block_status = qcow2_co_block_status, 4934 4935 .bdrv_co_preadv = qcow2_co_preadv, 4936 .bdrv_co_pwritev = qcow2_co_pwritev, 4937 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 4938 4939 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 4940 .bdrv_co_pdiscard = qcow2_co_pdiscard, 4941 .bdrv_co_copy_range_from = qcow2_co_copy_range_from, 4942 .bdrv_co_copy_range_to = qcow2_co_copy_range_to, 4943 .bdrv_co_truncate = qcow2_co_truncate, 4944 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 4945 .bdrv_make_empty = qcow2_make_empty, 4946 4947 .bdrv_snapshot_create = qcow2_snapshot_create, 4948 .bdrv_snapshot_goto = qcow2_snapshot_goto, 4949 .bdrv_snapshot_delete = qcow2_snapshot_delete, 4950 .bdrv_snapshot_list = qcow2_snapshot_list, 4951 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 4952 .bdrv_measure = qcow2_measure, 4953 .bdrv_get_info = qcow2_get_info, 4954 .bdrv_get_specific_info = qcow2_get_specific_info, 4955 4956 .bdrv_save_vmstate = qcow2_save_vmstate, 4957 .bdrv_load_vmstate = qcow2_load_vmstate, 4958 4959 .supports_backing = true, 4960 .bdrv_change_backing_file = qcow2_change_backing_file, 4961 4962 .bdrv_refresh_limits = qcow2_refresh_limits, 4963 .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, 4964 .bdrv_inactivate = qcow2_inactivate, 4965 4966 .create_opts = &qcow2_create_opts, 4967 .bdrv_co_check = qcow2_co_check, 4968 .bdrv_amend_options = qcow2_amend_options, 4969 4970 .bdrv_detach_aio_context = qcow2_detach_aio_context, 4971 .bdrv_attach_aio_context = qcow2_attach_aio_context, 4972 4973 .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw, 4974 .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap, 4975 .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap, 4976 }; 4977 4978 static void bdrv_qcow2_init(void) 4979 { 4980 bdrv_register(&bdrv_qcow2); 4981 } 4982 4983 block_init(bdrv_qcow2_init); 4984