1 /* 2 * Block driver for the QCOW 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 #include "qemu/osdep.h" 25 #include "qapi/error.h" 26 #include "qemu-common.h" 27 #include "qemu/error-report.h" 28 #include "block/block_int.h" 29 #include "sysemu/block-backend.h" 30 #include "qemu/module.h" 31 #include "qemu/bswap.h" 32 #include <zlib.h> 33 #include "qapi/qmp/qerror.h" 34 #include "qapi/qmp/qstring.h" 35 #include "crypto/block.h" 36 #include "migration/blocker.h" 37 #include "block/crypto.h" 38 39 /**************************************************************/ 40 /* QEMU COW block driver with compression and encryption support */ 41 42 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 43 #define QCOW_VERSION 1 44 45 #define QCOW_CRYPT_NONE 0 46 #define QCOW_CRYPT_AES 1 47 48 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 49 50 typedef struct QCowHeader { 51 uint32_t magic; 52 uint32_t version; 53 uint64_t backing_file_offset; 54 uint32_t backing_file_size; 55 uint32_t mtime; 56 uint64_t size; /* in bytes */ 57 uint8_t cluster_bits; 58 uint8_t l2_bits; 59 uint16_t padding; 60 uint32_t crypt_method; 61 uint64_t l1_table_offset; 62 } QEMU_PACKED QCowHeader; 63 64 #define L2_CACHE_SIZE 16 65 66 typedef struct BDRVQcowState { 67 int cluster_bits; 68 int cluster_size; 69 int cluster_sectors; 70 int l2_bits; 71 int l2_size; 72 unsigned int l1_size; 73 uint64_t cluster_offset_mask; 74 uint64_t l1_table_offset; 75 uint64_t *l1_table; 76 uint64_t *l2_cache; 77 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 78 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 79 uint8_t *cluster_cache; 80 uint8_t *cluster_data; 81 uint64_t cluster_cache_offset; 82 QCryptoBlock *crypto; /* Disk encryption format driver */ 83 uint32_t crypt_method_header; 84 CoMutex lock; 85 Error *migration_blocker; 86 } BDRVQcowState; 87 88 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 89 90 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 91 { 92 const QCowHeader *cow_header = (const void *)buf; 93 94 if (buf_size >= sizeof(QCowHeader) && 95 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 96 be32_to_cpu(cow_header->version) == QCOW_VERSION) 97 return 100; 98 else 99 return 0; 100 } 101 102 static QemuOptsList qcow_runtime_opts = { 103 .name = "qcow", 104 .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head), 105 .desc = { 106 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 107 { /* end of list */ } 108 }, 109 }; 110 111 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 112 Error **errp) 113 { 114 BDRVQcowState *s = bs->opaque; 115 unsigned int len, i, shift; 116 int ret; 117 QCowHeader header; 118 Error *local_err = NULL; 119 QCryptoBlockOpenOptions *crypto_opts = NULL; 120 unsigned int cflags = 0; 121 QDict *encryptopts = NULL; 122 const char *encryptfmt; 123 124 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 125 encryptfmt = qdict_get_try_str(encryptopts, "format"); 126 127 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 128 false, errp); 129 if (!bs->file) { 130 ret = -EINVAL; 131 goto fail; 132 } 133 134 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 135 if (ret < 0) { 136 goto fail; 137 } 138 be32_to_cpus(&header.magic); 139 be32_to_cpus(&header.version); 140 be64_to_cpus(&header.backing_file_offset); 141 be32_to_cpus(&header.backing_file_size); 142 be32_to_cpus(&header.mtime); 143 be64_to_cpus(&header.size); 144 be32_to_cpus(&header.crypt_method); 145 be64_to_cpus(&header.l1_table_offset); 146 147 if (header.magic != QCOW_MAGIC) { 148 error_setg(errp, "Image not in qcow format"); 149 ret = -EINVAL; 150 goto fail; 151 } 152 if (header.version != QCOW_VERSION) { 153 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 154 ret = -ENOTSUP; 155 goto fail; 156 } 157 158 if (header.size <= 1) { 159 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 160 ret = -EINVAL; 161 goto fail; 162 } 163 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 164 error_setg(errp, "Cluster size must be between 512 and 64k"); 165 ret = -EINVAL; 166 goto fail; 167 } 168 169 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 170 * so bytes = num_entries << 3. */ 171 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 172 error_setg(errp, "L2 table size must be between 512 and 64k"); 173 ret = -EINVAL; 174 goto fail; 175 } 176 177 s->crypt_method_header = header.crypt_method; 178 if (s->crypt_method_header) { 179 if (bdrv_uses_whitelist() && 180 s->crypt_method_header == QCOW_CRYPT_AES) { 181 error_setg(errp, 182 "Use of AES-CBC encrypted qcow images is no longer " 183 "supported in system emulators"); 184 error_append_hint(errp, 185 "You can use 'qemu-img convert' to convert your " 186 "image to an alternative supported format, such " 187 "as unencrypted qcow, or raw with the LUKS " 188 "format instead.\n"); 189 ret = -ENOSYS; 190 goto fail; 191 } 192 if (s->crypt_method_header == QCOW_CRYPT_AES) { 193 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 194 error_setg(errp, 195 "Header reported 'aes' encryption format but " 196 "options specify '%s'", encryptfmt); 197 ret = -EINVAL; 198 goto fail; 199 } 200 qdict_del(encryptopts, "format"); 201 crypto_opts = block_crypto_open_opts_init( 202 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 203 if (!crypto_opts) { 204 ret = -EINVAL; 205 goto fail; 206 } 207 208 if (flags & BDRV_O_NO_IO) { 209 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 210 } 211 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 212 NULL, NULL, cflags, errp); 213 if (!s->crypto) { 214 ret = -EINVAL; 215 goto fail; 216 } 217 } else { 218 error_setg(errp, "invalid encryption method in qcow header"); 219 ret = -EINVAL; 220 goto fail; 221 } 222 bs->encrypted = true; 223 } else { 224 if (encryptfmt) { 225 error_setg(errp, "No encryption in image header, but options " 226 "specified format '%s'", encryptfmt); 227 ret = -EINVAL; 228 goto fail; 229 } 230 } 231 s->cluster_bits = header.cluster_bits; 232 s->cluster_size = 1 << s->cluster_bits; 233 s->cluster_sectors = 1 << (s->cluster_bits - 9); 234 s->l2_bits = header.l2_bits; 235 s->l2_size = 1 << s->l2_bits; 236 bs->total_sectors = header.size / 512; 237 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 238 239 /* read the level 1 table */ 240 shift = s->cluster_bits + s->l2_bits; 241 if (header.size > UINT64_MAX - (1LL << shift)) { 242 error_setg(errp, "Image too large"); 243 ret = -EINVAL; 244 goto fail; 245 } else { 246 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 247 if (l1_size > INT_MAX / sizeof(uint64_t)) { 248 error_setg(errp, "Image too large"); 249 ret = -EINVAL; 250 goto fail; 251 } 252 s->l1_size = l1_size; 253 } 254 255 s->l1_table_offset = header.l1_table_offset; 256 s->l1_table = g_try_new(uint64_t, s->l1_size); 257 if (s->l1_table == NULL) { 258 error_setg(errp, "Could not allocate memory for L1 table"); 259 ret = -ENOMEM; 260 goto fail; 261 } 262 263 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 264 s->l1_size * sizeof(uint64_t)); 265 if (ret < 0) { 266 goto fail; 267 } 268 269 for(i = 0;i < s->l1_size; i++) { 270 be64_to_cpus(&s->l1_table[i]); 271 } 272 273 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 274 s->l2_cache = 275 qemu_try_blockalign(bs->file->bs, 276 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 277 if (s->l2_cache == NULL) { 278 error_setg(errp, "Could not allocate L2 table cache"); 279 ret = -ENOMEM; 280 goto fail; 281 } 282 s->cluster_cache = g_malloc(s->cluster_size); 283 s->cluster_data = g_malloc(s->cluster_size); 284 s->cluster_cache_offset = -1; 285 286 /* read the backing file name */ 287 if (header.backing_file_offset != 0) { 288 len = header.backing_file_size; 289 if (len > 1023 || len >= sizeof(bs->backing_file)) { 290 error_setg(errp, "Backing file name too long"); 291 ret = -EINVAL; 292 goto fail; 293 } 294 ret = bdrv_pread(bs->file, header.backing_file_offset, 295 bs->backing_file, len); 296 if (ret < 0) { 297 goto fail; 298 } 299 bs->backing_file[len] = '\0'; 300 } 301 302 /* Disable migration when qcow images are used */ 303 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 304 "does not support live migration", 305 bdrv_get_device_or_node_name(bs)); 306 ret = migrate_add_blocker(s->migration_blocker, &local_err); 307 if (local_err) { 308 error_propagate(errp, local_err); 309 error_free(s->migration_blocker); 310 goto fail; 311 } 312 313 QDECREF(encryptopts); 314 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 315 qemu_co_mutex_init(&s->lock); 316 return 0; 317 318 fail: 319 g_free(s->l1_table); 320 qemu_vfree(s->l2_cache); 321 g_free(s->cluster_cache); 322 g_free(s->cluster_data); 323 qcrypto_block_free(s->crypto); 324 QDECREF(encryptopts); 325 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 326 return ret; 327 } 328 329 330 /* We have nothing to do for QCOW reopen, stubs just return 331 * success */ 332 static int qcow_reopen_prepare(BDRVReopenState *state, 333 BlockReopenQueue *queue, Error **errp) 334 { 335 return 0; 336 } 337 338 339 /* 'allocate' is: 340 * 341 * 0 to not allocate. 342 * 343 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 344 * 'n_end') 345 * 346 * 2 to allocate a compressed cluster of size 347 * 'compressed_size'. 'compressed_size' must be > 0 and < 348 * cluster_size 349 * 350 * return 0 if not allocated, 1 if *result is assigned, and negative 351 * errno on failure. 352 */ 353 static int get_cluster_offset(BlockDriverState *bs, 354 uint64_t offset, int allocate, 355 int compressed_size, 356 int n_start, int n_end, uint64_t *result) 357 { 358 BDRVQcowState *s = bs->opaque; 359 int min_index, i, j, l1_index, l2_index, ret; 360 int64_t l2_offset; 361 uint64_t *l2_table, cluster_offset, tmp; 362 uint32_t min_count; 363 int new_l2_table; 364 365 *result = 0; 366 l1_index = offset >> (s->l2_bits + s->cluster_bits); 367 l2_offset = s->l1_table[l1_index]; 368 new_l2_table = 0; 369 if (!l2_offset) { 370 if (!allocate) 371 return 0; 372 /* allocate a new l2 entry */ 373 l2_offset = bdrv_getlength(bs->file->bs); 374 if (l2_offset < 0) { 375 return l2_offset; 376 } 377 /* round to cluster size */ 378 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 379 /* update the L1 entry */ 380 s->l1_table[l1_index] = l2_offset; 381 tmp = cpu_to_be64(l2_offset); 382 ret = bdrv_pwrite_sync(bs->file, 383 s->l1_table_offset + l1_index * sizeof(tmp), 384 &tmp, sizeof(tmp)); 385 if (ret < 0) { 386 return ret; 387 } 388 new_l2_table = 1; 389 } 390 for(i = 0; i < L2_CACHE_SIZE; i++) { 391 if (l2_offset == s->l2_cache_offsets[i]) { 392 /* increment the hit count */ 393 if (++s->l2_cache_counts[i] == 0xffffffff) { 394 for(j = 0; j < L2_CACHE_SIZE; j++) { 395 s->l2_cache_counts[j] >>= 1; 396 } 397 } 398 l2_table = s->l2_cache + (i << s->l2_bits); 399 goto found; 400 } 401 } 402 /* not found: load a new entry in the least used one */ 403 min_index = 0; 404 min_count = 0xffffffff; 405 for(i = 0; i < L2_CACHE_SIZE; i++) { 406 if (s->l2_cache_counts[i] < min_count) { 407 min_count = s->l2_cache_counts[i]; 408 min_index = i; 409 } 410 } 411 l2_table = s->l2_cache + (min_index << s->l2_bits); 412 if (new_l2_table) { 413 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 414 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 415 s->l2_size * sizeof(uint64_t)); 416 if (ret < 0) { 417 return ret; 418 } 419 } else { 420 ret = bdrv_pread(bs->file, l2_offset, l2_table, 421 s->l2_size * sizeof(uint64_t)); 422 if (ret < 0) { 423 return ret; 424 } 425 } 426 s->l2_cache_offsets[min_index] = l2_offset; 427 s->l2_cache_counts[min_index] = 1; 428 found: 429 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 430 cluster_offset = be64_to_cpu(l2_table[l2_index]); 431 if (!cluster_offset || 432 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 433 if (!allocate) 434 return 0; 435 /* allocate a new cluster */ 436 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 437 (n_end - n_start) < s->cluster_sectors) { 438 /* if the cluster is already compressed, we must 439 decompress it in the case it is not completely 440 overwritten */ 441 if (decompress_cluster(bs, cluster_offset) < 0) { 442 return -EIO; 443 } 444 cluster_offset = bdrv_getlength(bs->file->bs); 445 if ((int64_t) cluster_offset < 0) { 446 return cluster_offset; 447 } 448 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 449 /* write the cluster content */ 450 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 451 s->cluster_size); 452 if (ret < 0) { 453 return ret; 454 } 455 } else { 456 cluster_offset = bdrv_getlength(bs->file->bs); 457 if ((int64_t) cluster_offset < 0) { 458 return cluster_offset; 459 } 460 if (allocate == 1) { 461 /* round to cluster size */ 462 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 463 if (cluster_offset + s->cluster_size > INT64_MAX) { 464 return -E2BIG; 465 } 466 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 467 PREALLOC_MODE_OFF, NULL); 468 if (ret < 0) { 469 return ret; 470 } 471 /* if encrypted, we must initialize the cluster 472 content which won't be written */ 473 if (bs->encrypted && 474 (n_end - n_start) < s->cluster_sectors) { 475 uint64_t start_sect; 476 assert(s->crypto); 477 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 478 for(i = 0; i < s->cluster_sectors; i++) { 479 if (i < n_start || i >= n_end) { 480 memset(s->cluster_data, 0x00, 512); 481 if (qcrypto_block_encrypt(s->crypto, start_sect + i, 482 s->cluster_data, 483 BDRV_SECTOR_SIZE, 484 NULL) < 0) { 485 return -EIO; 486 } 487 ret = bdrv_pwrite(bs->file, 488 cluster_offset + i * 512, 489 s->cluster_data, 512); 490 if (ret < 0) { 491 return ret; 492 } 493 } 494 } 495 } 496 } else if (allocate == 2) { 497 cluster_offset |= QCOW_OFLAG_COMPRESSED | 498 (uint64_t)compressed_size << (63 - s->cluster_bits); 499 } 500 } 501 /* update L2 table */ 502 tmp = cpu_to_be64(cluster_offset); 503 l2_table[l2_index] = tmp; 504 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 505 &tmp, sizeof(tmp)); 506 if (ret < 0) { 507 return ret; 508 } 509 } 510 *result = cluster_offset; 511 return 1; 512 } 513 514 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 515 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 516 { 517 BDRVQcowState *s = bs->opaque; 518 int index_in_cluster, n, ret; 519 uint64_t cluster_offset; 520 521 qemu_co_mutex_lock(&s->lock); 522 ret = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0, &cluster_offset); 523 qemu_co_mutex_unlock(&s->lock); 524 if (ret < 0) { 525 return ret; 526 } 527 index_in_cluster = sector_num & (s->cluster_sectors - 1); 528 n = s->cluster_sectors - index_in_cluster; 529 if (n > nb_sectors) 530 n = nb_sectors; 531 *pnum = n; 532 if (!cluster_offset) { 533 return 0; 534 } 535 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 536 return BDRV_BLOCK_DATA; 537 } 538 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 539 *file = bs->file->bs; 540 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 541 } 542 543 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 544 const uint8_t *buf, int buf_size) 545 { 546 z_stream strm1, *strm = &strm1; 547 int ret, out_len; 548 549 memset(strm, 0, sizeof(*strm)); 550 551 strm->next_in = (uint8_t *)buf; 552 strm->avail_in = buf_size; 553 strm->next_out = out_buf; 554 strm->avail_out = out_buf_size; 555 556 ret = inflateInit2(strm, -12); 557 if (ret != Z_OK) 558 return -1; 559 ret = inflate(strm, Z_FINISH); 560 out_len = strm->next_out - out_buf; 561 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 562 out_len != out_buf_size) { 563 inflateEnd(strm); 564 return -1; 565 } 566 inflateEnd(strm); 567 return 0; 568 } 569 570 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 571 { 572 BDRVQcowState *s = bs->opaque; 573 int ret, csize; 574 uint64_t coffset; 575 576 coffset = cluster_offset & s->cluster_offset_mask; 577 if (s->cluster_cache_offset != coffset) { 578 csize = cluster_offset >> (63 - s->cluster_bits); 579 csize &= (s->cluster_size - 1); 580 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 581 if (ret != csize) 582 return -1; 583 if (decompress_buffer(s->cluster_cache, s->cluster_size, 584 s->cluster_data, csize) < 0) { 585 return -1; 586 } 587 s->cluster_cache_offset = coffset; 588 } 589 return 0; 590 } 591 592 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 593 int nb_sectors, QEMUIOVector *qiov) 594 { 595 BDRVQcowState *s = bs->opaque; 596 int index_in_cluster; 597 int ret = 0, n; 598 uint64_t cluster_offset; 599 struct iovec hd_iov; 600 QEMUIOVector hd_qiov; 601 uint8_t *buf; 602 void *orig_buf; 603 604 if (qiov->niov > 1) { 605 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 606 if (buf == NULL) { 607 return -ENOMEM; 608 } 609 } else { 610 orig_buf = NULL; 611 buf = (uint8_t *)qiov->iov->iov_base; 612 } 613 614 qemu_co_mutex_lock(&s->lock); 615 616 while (nb_sectors != 0) { 617 /* prepare next request */ 618 ret = get_cluster_offset(bs, sector_num << 9, 619 0, 0, 0, 0, &cluster_offset); 620 if (ret < 0) { 621 break; 622 } 623 index_in_cluster = sector_num & (s->cluster_sectors - 1); 624 n = s->cluster_sectors - index_in_cluster; 625 if (n > nb_sectors) { 626 n = nb_sectors; 627 } 628 629 if (!cluster_offset) { 630 if (bs->backing) { 631 /* read from the base image */ 632 hd_iov.iov_base = (void *)buf; 633 hd_iov.iov_len = n * 512; 634 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 635 qemu_co_mutex_unlock(&s->lock); 636 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 637 qemu_co_mutex_lock(&s->lock); 638 if (ret < 0) { 639 break; 640 } 641 } else { 642 /* Note: in this case, no need to wait */ 643 memset(buf, 0, 512 * n); 644 } 645 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 646 /* add AIO support for compressed blocks ? */ 647 if (decompress_cluster(bs, cluster_offset) < 0) { 648 ret = -EIO; 649 break; 650 } 651 memcpy(buf, 652 s->cluster_cache + index_in_cluster * 512, 512 * n); 653 } else { 654 if ((cluster_offset & 511) != 0) { 655 ret = -EIO; 656 break; 657 } 658 hd_iov.iov_base = (void *)buf; 659 hd_iov.iov_len = n * 512; 660 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 661 qemu_co_mutex_unlock(&s->lock); 662 ret = bdrv_co_readv(bs->file, 663 (cluster_offset >> 9) + index_in_cluster, 664 n, &hd_qiov); 665 qemu_co_mutex_lock(&s->lock); 666 if (ret < 0) { 667 break; 668 } 669 if (bs->encrypted) { 670 assert(s->crypto); 671 if (qcrypto_block_decrypt(s->crypto, sector_num, buf, 672 n * BDRV_SECTOR_SIZE, NULL) < 0) { 673 ret = -EIO; 674 break; 675 } 676 } 677 } 678 ret = 0; 679 680 nb_sectors -= n; 681 sector_num += n; 682 buf += n * 512; 683 } 684 685 qemu_co_mutex_unlock(&s->lock); 686 687 if (qiov->niov > 1) { 688 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 689 qemu_vfree(orig_buf); 690 } 691 692 return ret; 693 } 694 695 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 696 int nb_sectors, QEMUIOVector *qiov) 697 { 698 BDRVQcowState *s = bs->opaque; 699 int index_in_cluster; 700 uint64_t cluster_offset; 701 int ret = 0, n; 702 struct iovec hd_iov; 703 QEMUIOVector hd_qiov; 704 uint8_t *buf; 705 void *orig_buf; 706 707 s->cluster_cache_offset = -1; /* disable compressed cache */ 708 709 /* We must always copy the iov when encrypting, so we 710 * don't modify the original data buffer during encryption */ 711 if (bs->encrypted || qiov->niov > 1) { 712 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 713 if (buf == NULL) { 714 return -ENOMEM; 715 } 716 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 717 } else { 718 orig_buf = NULL; 719 buf = (uint8_t *)qiov->iov->iov_base; 720 } 721 722 qemu_co_mutex_lock(&s->lock); 723 724 while (nb_sectors != 0) { 725 726 index_in_cluster = sector_num & (s->cluster_sectors - 1); 727 n = s->cluster_sectors - index_in_cluster; 728 if (n > nb_sectors) { 729 n = nb_sectors; 730 } 731 ret = get_cluster_offset(bs, sector_num << 9, 1, 0, 732 index_in_cluster, 733 index_in_cluster + n, &cluster_offset); 734 if (ret < 0) { 735 break; 736 } 737 if (!cluster_offset || (cluster_offset & 511) != 0) { 738 ret = -EIO; 739 break; 740 } 741 if (bs->encrypted) { 742 assert(s->crypto); 743 if (qcrypto_block_encrypt(s->crypto, sector_num, buf, 744 n * BDRV_SECTOR_SIZE, NULL) < 0) { 745 ret = -EIO; 746 break; 747 } 748 } 749 750 hd_iov.iov_base = (void *)buf; 751 hd_iov.iov_len = n * 512; 752 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 753 qemu_co_mutex_unlock(&s->lock); 754 ret = bdrv_co_writev(bs->file, 755 (cluster_offset >> 9) + index_in_cluster, 756 n, &hd_qiov); 757 qemu_co_mutex_lock(&s->lock); 758 if (ret < 0) { 759 break; 760 } 761 ret = 0; 762 763 nb_sectors -= n; 764 sector_num += n; 765 buf += n * 512; 766 } 767 qemu_co_mutex_unlock(&s->lock); 768 769 qemu_vfree(orig_buf); 770 771 return ret; 772 } 773 774 static void qcow_close(BlockDriverState *bs) 775 { 776 BDRVQcowState *s = bs->opaque; 777 778 qcrypto_block_free(s->crypto); 779 s->crypto = NULL; 780 g_free(s->l1_table); 781 qemu_vfree(s->l2_cache); 782 g_free(s->cluster_cache); 783 g_free(s->cluster_data); 784 785 migrate_del_blocker(s->migration_blocker); 786 error_free(s->migration_blocker); 787 } 788 789 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 790 { 791 int header_size, backing_filename_len, l1_size, shift, i; 792 QCowHeader header; 793 uint8_t *tmp; 794 int64_t total_size = 0; 795 char *backing_file = NULL; 796 Error *local_err = NULL; 797 int ret; 798 BlockBackend *qcow_blk; 799 char *encryptfmt = NULL; 800 QDict *options; 801 QDict *encryptopts = NULL; 802 QCryptoBlockCreateOptions *crypto_opts = NULL; 803 QCryptoBlock *crypto = NULL; 804 805 /* Read out options */ 806 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 807 BDRV_SECTOR_SIZE); 808 if (total_size == 0) { 809 error_setg(errp, "Image size is too small, cannot be zero length"); 810 ret = -EINVAL; 811 goto cleanup; 812 } 813 814 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 815 encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 816 if (encryptfmt) { 817 if (qemu_opt_get(opts, BLOCK_OPT_ENCRYPT)) { 818 error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and " 819 BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive"); 820 ret = -EINVAL; 821 goto cleanup; 822 } 823 } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 824 encryptfmt = g_strdup("aes"); 825 } 826 827 ret = bdrv_create_file(filename, opts, &local_err); 828 if (ret < 0) { 829 error_propagate(errp, local_err); 830 goto cleanup; 831 } 832 833 qcow_blk = blk_new_open(filename, NULL, NULL, 834 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 835 &local_err); 836 if (qcow_blk == NULL) { 837 error_propagate(errp, local_err); 838 ret = -EIO; 839 goto cleanup; 840 } 841 842 blk_set_allow_write_beyond_eof(qcow_blk, true); 843 844 ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp); 845 if (ret < 0) { 846 goto exit; 847 } 848 849 memset(&header, 0, sizeof(header)); 850 header.magic = cpu_to_be32(QCOW_MAGIC); 851 header.version = cpu_to_be32(QCOW_VERSION); 852 header.size = cpu_to_be64(total_size); 853 header_size = sizeof(header); 854 backing_filename_len = 0; 855 if (backing_file) { 856 if (strcmp(backing_file, "fat:")) { 857 header.backing_file_offset = cpu_to_be64(header_size); 858 backing_filename_len = strlen(backing_file); 859 header.backing_file_size = cpu_to_be32(backing_filename_len); 860 header_size += backing_filename_len; 861 } else { 862 /* special backing file for vvfat */ 863 g_free(backing_file); 864 backing_file = NULL; 865 } 866 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 867 unmodified sectors */ 868 header.l2_bits = 12; /* 32 KB L2 tables */ 869 } else { 870 header.cluster_bits = 12; /* 4 KB clusters */ 871 header.l2_bits = 9; /* 4 KB L2 tables */ 872 } 873 header_size = (header_size + 7) & ~7; 874 shift = header.cluster_bits + header.l2_bits; 875 l1_size = (total_size + (1LL << shift) - 1) >> shift; 876 877 header.l1_table_offset = cpu_to_be64(header_size); 878 879 options = qemu_opts_to_qdict(opts, NULL); 880 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 881 QDECREF(options); 882 if (encryptfmt) { 883 if (!g_str_equal(encryptfmt, "aes")) { 884 error_setg(errp, "Unknown encryption format '%s', expected 'aes'", 885 encryptfmt); 886 ret = -EINVAL; 887 goto exit; 888 } 889 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 890 891 crypto_opts = block_crypto_create_opts_init( 892 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 893 if (!crypto_opts) { 894 ret = -EINVAL; 895 goto exit; 896 } 897 898 crypto = qcrypto_block_create(crypto_opts, "encrypt.", 899 NULL, NULL, NULL, errp); 900 if (!crypto) { 901 ret = -EINVAL; 902 goto exit; 903 } 904 } else { 905 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 906 } 907 908 /* write all the data */ 909 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 910 if (ret != sizeof(header)) { 911 goto exit; 912 } 913 914 if (backing_file) { 915 ret = blk_pwrite(qcow_blk, sizeof(header), 916 backing_file, backing_filename_len, 0); 917 if (ret != backing_filename_len) { 918 goto exit; 919 } 920 } 921 922 tmp = g_malloc0(BDRV_SECTOR_SIZE); 923 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 924 i++) { 925 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 926 tmp, BDRV_SECTOR_SIZE, 0); 927 if (ret != BDRV_SECTOR_SIZE) { 928 g_free(tmp); 929 goto exit; 930 } 931 } 932 933 g_free(tmp); 934 ret = 0; 935 exit: 936 blk_unref(qcow_blk); 937 cleanup: 938 QDECREF(encryptopts); 939 g_free(encryptfmt); 940 qcrypto_block_free(crypto); 941 qapi_free_QCryptoBlockCreateOptions(crypto_opts); 942 g_free(backing_file); 943 return ret; 944 } 945 946 static int qcow_make_empty(BlockDriverState *bs) 947 { 948 BDRVQcowState *s = bs->opaque; 949 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 950 int ret; 951 952 memset(s->l1_table, 0, l1_length); 953 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 954 l1_length) < 0) 955 return -1; 956 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, 957 PREALLOC_MODE_OFF, NULL); 958 if (ret < 0) 959 return ret; 960 961 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 962 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 963 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 964 965 return 0; 966 } 967 968 /* XXX: put compressed sectors first, then all the cluster aligned 969 tables to avoid losing bytes in alignment */ 970 static coroutine_fn int 971 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 972 uint64_t bytes, QEMUIOVector *qiov) 973 { 974 BDRVQcowState *s = bs->opaque; 975 QEMUIOVector hd_qiov; 976 struct iovec iov; 977 z_stream strm; 978 int ret, out_len; 979 uint8_t *buf, *out_buf; 980 uint64_t cluster_offset; 981 982 buf = qemu_blockalign(bs, s->cluster_size); 983 if (bytes != s->cluster_size) { 984 if (bytes > s->cluster_size || 985 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 986 { 987 qemu_vfree(buf); 988 return -EINVAL; 989 } 990 /* Zero-pad last write if image size is not cluster aligned */ 991 memset(buf + bytes, 0, s->cluster_size - bytes); 992 } 993 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 994 995 out_buf = g_malloc(s->cluster_size); 996 997 /* best compression, small window, no zlib header */ 998 memset(&strm, 0, sizeof(strm)); 999 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 1000 Z_DEFLATED, -12, 1001 9, Z_DEFAULT_STRATEGY); 1002 if (ret != 0) { 1003 ret = -EINVAL; 1004 goto fail; 1005 } 1006 1007 strm.avail_in = s->cluster_size; 1008 strm.next_in = (uint8_t *)buf; 1009 strm.avail_out = s->cluster_size; 1010 strm.next_out = out_buf; 1011 1012 ret = deflate(&strm, Z_FINISH); 1013 if (ret != Z_STREAM_END && ret != Z_OK) { 1014 deflateEnd(&strm); 1015 ret = -EINVAL; 1016 goto fail; 1017 } 1018 out_len = strm.next_out - out_buf; 1019 1020 deflateEnd(&strm); 1021 1022 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1023 /* could not compress: write normal cluster */ 1024 ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS, 1025 bytes >> BDRV_SECTOR_BITS, qiov); 1026 if (ret < 0) { 1027 goto fail; 1028 } 1029 goto success; 1030 } 1031 qemu_co_mutex_lock(&s->lock); 1032 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); 1033 qemu_co_mutex_unlock(&s->lock); 1034 if (ret < 0) { 1035 goto fail; 1036 } 1037 if (cluster_offset == 0) { 1038 ret = -EIO; 1039 goto fail; 1040 } 1041 cluster_offset &= s->cluster_offset_mask; 1042 1043 iov = (struct iovec) { 1044 .iov_base = out_buf, 1045 .iov_len = out_len, 1046 }; 1047 qemu_iovec_init_external(&hd_qiov, &iov, 1); 1048 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1049 if (ret < 0) { 1050 goto fail; 1051 } 1052 success: 1053 ret = 0; 1054 fail: 1055 qemu_vfree(buf); 1056 g_free(out_buf); 1057 return ret; 1058 } 1059 1060 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1061 { 1062 BDRVQcowState *s = bs->opaque; 1063 bdi->cluster_size = s->cluster_size; 1064 return 0; 1065 } 1066 1067 static QemuOptsList qcow_create_opts = { 1068 .name = "qcow-create-opts", 1069 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1070 .desc = { 1071 { 1072 .name = BLOCK_OPT_SIZE, 1073 .type = QEMU_OPT_SIZE, 1074 .help = "Virtual disk size" 1075 }, 1076 { 1077 .name = BLOCK_OPT_BACKING_FILE, 1078 .type = QEMU_OPT_STRING, 1079 .help = "File name of a base image" 1080 }, 1081 { 1082 .name = BLOCK_OPT_ENCRYPT, 1083 .type = QEMU_OPT_BOOL, 1084 .help = "Encrypt the image with format 'aes'. (Deprecated " 1085 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1086 }, 1087 { 1088 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1089 .type = QEMU_OPT_STRING, 1090 .help = "Encrypt the image, format choices: 'aes'", 1091 }, 1092 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1093 { /* end of list */ } 1094 } 1095 }; 1096 1097 static BlockDriver bdrv_qcow = { 1098 .format_name = "qcow", 1099 .instance_size = sizeof(BDRVQcowState), 1100 .bdrv_probe = qcow_probe, 1101 .bdrv_open = qcow_open, 1102 .bdrv_close = qcow_close, 1103 .bdrv_child_perm = bdrv_format_default_perms, 1104 .bdrv_reopen_prepare = qcow_reopen_prepare, 1105 .bdrv_create = qcow_create, 1106 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1107 .supports_backing = true, 1108 1109 .bdrv_co_readv = qcow_co_readv, 1110 .bdrv_co_writev = qcow_co_writev, 1111 .bdrv_co_get_block_status = qcow_co_get_block_status, 1112 1113 .bdrv_make_empty = qcow_make_empty, 1114 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1115 .bdrv_get_info = qcow_get_info, 1116 1117 .create_opts = &qcow_create_opts, 1118 }; 1119 1120 static void bdrv_qcow_init(void) 1121 { 1122 bdrv_register(&bdrv_qcow); 1123 } 1124 1125 block_init(bdrv_qcow_init); 1126