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. 351 */ 352 static uint64_t get_cluster_offset(BlockDriverState *bs, 353 uint64_t offset, int allocate, 354 int compressed_size, 355 int n_start, int n_end) 356 { 357 BDRVQcowState *s = bs->opaque; 358 int min_index, i, j, l1_index, l2_index; 359 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 360 uint32_t min_count; 361 int new_l2_table; 362 363 l1_index = offset >> (s->l2_bits + s->cluster_bits); 364 l2_offset = s->l1_table[l1_index]; 365 new_l2_table = 0; 366 if (!l2_offset) { 367 if (!allocate) 368 return 0; 369 /* allocate a new l2 entry */ 370 l2_offset = bdrv_getlength(bs->file->bs); 371 /* round to cluster size */ 372 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 373 /* update the L1 entry */ 374 s->l1_table[l1_index] = l2_offset; 375 tmp = cpu_to_be64(l2_offset); 376 if (bdrv_pwrite_sync(bs->file, 377 s->l1_table_offset + l1_index * sizeof(tmp), 378 &tmp, sizeof(tmp)) < 0) 379 return 0; 380 new_l2_table = 1; 381 } 382 for(i = 0; i < L2_CACHE_SIZE; i++) { 383 if (l2_offset == s->l2_cache_offsets[i]) { 384 /* increment the hit count */ 385 if (++s->l2_cache_counts[i] == 0xffffffff) { 386 for(j = 0; j < L2_CACHE_SIZE; j++) { 387 s->l2_cache_counts[j] >>= 1; 388 } 389 } 390 l2_table = s->l2_cache + (i << s->l2_bits); 391 goto found; 392 } 393 } 394 /* not found: load a new entry in the least used one */ 395 min_index = 0; 396 min_count = 0xffffffff; 397 for(i = 0; i < L2_CACHE_SIZE; i++) { 398 if (s->l2_cache_counts[i] < min_count) { 399 min_count = s->l2_cache_counts[i]; 400 min_index = i; 401 } 402 } 403 l2_table = s->l2_cache + (min_index << s->l2_bits); 404 if (new_l2_table) { 405 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 406 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 407 s->l2_size * sizeof(uint64_t)) < 0) 408 return 0; 409 } else { 410 if (bdrv_pread(bs->file, l2_offset, l2_table, 411 s->l2_size * sizeof(uint64_t)) != 412 s->l2_size * sizeof(uint64_t)) 413 return 0; 414 } 415 s->l2_cache_offsets[min_index] = l2_offset; 416 s->l2_cache_counts[min_index] = 1; 417 found: 418 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 419 cluster_offset = be64_to_cpu(l2_table[l2_index]); 420 if (!cluster_offset || 421 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 422 if (!allocate) 423 return 0; 424 /* allocate a new cluster */ 425 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 426 (n_end - n_start) < s->cluster_sectors) { 427 /* if the cluster is already compressed, we must 428 decompress it in the case it is not completely 429 overwritten */ 430 if (decompress_cluster(bs, cluster_offset) < 0) 431 return 0; 432 cluster_offset = bdrv_getlength(bs->file->bs); 433 cluster_offset = (cluster_offset + s->cluster_size - 1) & 434 ~(s->cluster_size - 1); 435 /* write the cluster content */ 436 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 437 s->cluster_size) != 438 s->cluster_size) 439 return -1; 440 } else { 441 cluster_offset = bdrv_getlength(bs->file->bs); 442 if (allocate == 1) { 443 /* round to cluster size */ 444 cluster_offset = (cluster_offset + s->cluster_size - 1) & 445 ~(s->cluster_size - 1); 446 bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 447 PREALLOC_MODE_OFF, NULL); 448 /* if encrypted, we must initialize the cluster 449 content which won't be written */ 450 if (bs->encrypted && 451 (n_end - n_start) < s->cluster_sectors) { 452 uint64_t start_sect; 453 assert(s->crypto); 454 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 455 for(i = 0; i < s->cluster_sectors; i++) { 456 if (i < n_start || i >= n_end) { 457 Error *err = NULL; 458 memset(s->cluster_data, 0x00, 512); 459 if (qcrypto_block_encrypt(s->crypto, start_sect + i, 460 s->cluster_data, 461 BDRV_SECTOR_SIZE, 462 &err) < 0) { 463 error_free(err); 464 errno = EIO; 465 return -1; 466 } 467 if (bdrv_pwrite(bs->file, 468 cluster_offset + i * 512, 469 s->cluster_data, 512) != 512) 470 return -1; 471 } 472 } 473 } 474 } else if (allocate == 2) { 475 cluster_offset |= QCOW_OFLAG_COMPRESSED | 476 (uint64_t)compressed_size << (63 - s->cluster_bits); 477 } 478 } 479 /* update L2 table */ 480 tmp = cpu_to_be64(cluster_offset); 481 l2_table[l2_index] = tmp; 482 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 483 &tmp, sizeof(tmp)) < 0) 484 return 0; 485 } 486 return cluster_offset; 487 } 488 489 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 490 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 491 { 492 BDRVQcowState *s = bs->opaque; 493 int index_in_cluster, n; 494 uint64_t cluster_offset; 495 496 qemu_co_mutex_lock(&s->lock); 497 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 498 qemu_co_mutex_unlock(&s->lock); 499 index_in_cluster = sector_num & (s->cluster_sectors - 1); 500 n = s->cluster_sectors - index_in_cluster; 501 if (n > nb_sectors) 502 n = nb_sectors; 503 *pnum = n; 504 if (!cluster_offset) { 505 return 0; 506 } 507 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 508 return BDRV_BLOCK_DATA; 509 } 510 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 511 *file = bs->file->bs; 512 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 513 } 514 515 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 516 const uint8_t *buf, int buf_size) 517 { 518 z_stream strm1, *strm = &strm1; 519 int ret, out_len; 520 521 memset(strm, 0, sizeof(*strm)); 522 523 strm->next_in = (uint8_t *)buf; 524 strm->avail_in = buf_size; 525 strm->next_out = out_buf; 526 strm->avail_out = out_buf_size; 527 528 ret = inflateInit2(strm, -12); 529 if (ret != Z_OK) 530 return -1; 531 ret = inflate(strm, Z_FINISH); 532 out_len = strm->next_out - out_buf; 533 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 534 out_len != out_buf_size) { 535 inflateEnd(strm); 536 return -1; 537 } 538 inflateEnd(strm); 539 return 0; 540 } 541 542 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 543 { 544 BDRVQcowState *s = bs->opaque; 545 int ret, csize; 546 uint64_t coffset; 547 548 coffset = cluster_offset & s->cluster_offset_mask; 549 if (s->cluster_cache_offset != coffset) { 550 csize = cluster_offset >> (63 - s->cluster_bits); 551 csize &= (s->cluster_size - 1); 552 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 553 if (ret != csize) 554 return -1; 555 if (decompress_buffer(s->cluster_cache, s->cluster_size, 556 s->cluster_data, csize) < 0) { 557 return -1; 558 } 559 s->cluster_cache_offset = coffset; 560 } 561 return 0; 562 } 563 564 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 565 int nb_sectors, QEMUIOVector *qiov) 566 { 567 BDRVQcowState *s = bs->opaque; 568 int index_in_cluster; 569 int ret = 0, n; 570 uint64_t cluster_offset; 571 struct iovec hd_iov; 572 QEMUIOVector hd_qiov; 573 uint8_t *buf; 574 void *orig_buf; 575 Error *err = NULL; 576 577 if (qiov->niov > 1) { 578 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 579 if (buf == NULL) { 580 return -ENOMEM; 581 } 582 } else { 583 orig_buf = NULL; 584 buf = (uint8_t *)qiov->iov->iov_base; 585 } 586 587 qemu_co_mutex_lock(&s->lock); 588 589 while (nb_sectors != 0) { 590 /* prepare next request */ 591 cluster_offset = get_cluster_offset(bs, sector_num << 9, 592 0, 0, 0, 0); 593 index_in_cluster = sector_num & (s->cluster_sectors - 1); 594 n = s->cluster_sectors - index_in_cluster; 595 if (n > nb_sectors) { 596 n = nb_sectors; 597 } 598 599 if (!cluster_offset) { 600 if (bs->backing) { 601 /* read from the base image */ 602 hd_iov.iov_base = (void *)buf; 603 hd_iov.iov_len = n * 512; 604 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 605 qemu_co_mutex_unlock(&s->lock); 606 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 607 qemu_co_mutex_lock(&s->lock); 608 if (ret < 0) { 609 goto fail; 610 } 611 } else { 612 /* Note: in this case, no need to wait */ 613 memset(buf, 0, 512 * n); 614 } 615 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 616 /* add AIO support for compressed blocks ? */ 617 if (decompress_cluster(bs, cluster_offset) < 0) { 618 goto fail; 619 } 620 memcpy(buf, 621 s->cluster_cache + index_in_cluster * 512, 512 * n); 622 } else { 623 if ((cluster_offset & 511) != 0) { 624 goto fail; 625 } 626 hd_iov.iov_base = (void *)buf; 627 hd_iov.iov_len = n * 512; 628 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 629 qemu_co_mutex_unlock(&s->lock); 630 ret = bdrv_co_readv(bs->file, 631 (cluster_offset >> 9) + index_in_cluster, 632 n, &hd_qiov); 633 qemu_co_mutex_lock(&s->lock); 634 if (ret < 0) { 635 break; 636 } 637 if (bs->encrypted) { 638 assert(s->crypto); 639 if (qcrypto_block_decrypt(s->crypto, sector_num, buf, 640 n * BDRV_SECTOR_SIZE, &err) < 0) { 641 goto fail; 642 } 643 } 644 } 645 ret = 0; 646 647 nb_sectors -= n; 648 sector_num += n; 649 buf += n * 512; 650 } 651 652 done: 653 qemu_co_mutex_unlock(&s->lock); 654 655 if (qiov->niov > 1) { 656 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 657 qemu_vfree(orig_buf); 658 } 659 660 return ret; 661 662 fail: 663 error_free(err); 664 ret = -EIO; 665 goto done; 666 } 667 668 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 669 int nb_sectors, QEMUIOVector *qiov) 670 { 671 BDRVQcowState *s = bs->opaque; 672 int index_in_cluster; 673 uint64_t cluster_offset; 674 int ret = 0, n; 675 struct iovec hd_iov; 676 QEMUIOVector hd_qiov; 677 uint8_t *buf; 678 void *orig_buf; 679 680 s->cluster_cache_offset = -1; /* disable compressed cache */ 681 682 /* We must always copy the iov when encrypting, so we 683 * don't modify the original data buffer during encryption */ 684 if (bs->encrypted || qiov->niov > 1) { 685 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 686 if (buf == NULL) { 687 return -ENOMEM; 688 } 689 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 690 } else { 691 orig_buf = NULL; 692 buf = (uint8_t *)qiov->iov->iov_base; 693 } 694 695 qemu_co_mutex_lock(&s->lock); 696 697 while (nb_sectors != 0) { 698 699 index_in_cluster = sector_num & (s->cluster_sectors - 1); 700 n = s->cluster_sectors - index_in_cluster; 701 if (n > nb_sectors) { 702 n = nb_sectors; 703 } 704 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 705 index_in_cluster, 706 index_in_cluster + n); 707 if (!cluster_offset || (cluster_offset & 511) != 0) { 708 ret = -EIO; 709 break; 710 } 711 if (bs->encrypted) { 712 Error *err = NULL; 713 assert(s->crypto); 714 if (qcrypto_block_encrypt(s->crypto, sector_num, buf, 715 n * BDRV_SECTOR_SIZE, &err) < 0) { 716 error_free(err); 717 ret = -EIO; 718 break; 719 } 720 } 721 722 hd_iov.iov_base = (void *)buf; 723 hd_iov.iov_len = n * 512; 724 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 725 qemu_co_mutex_unlock(&s->lock); 726 ret = bdrv_co_writev(bs->file, 727 (cluster_offset >> 9) + index_in_cluster, 728 n, &hd_qiov); 729 qemu_co_mutex_lock(&s->lock); 730 if (ret < 0) { 731 break; 732 } 733 ret = 0; 734 735 nb_sectors -= n; 736 sector_num += n; 737 buf += n * 512; 738 } 739 qemu_co_mutex_unlock(&s->lock); 740 741 qemu_vfree(orig_buf); 742 743 return ret; 744 } 745 746 static void qcow_close(BlockDriverState *bs) 747 { 748 BDRVQcowState *s = bs->opaque; 749 750 qcrypto_block_free(s->crypto); 751 s->crypto = NULL; 752 g_free(s->l1_table); 753 qemu_vfree(s->l2_cache); 754 g_free(s->cluster_cache); 755 g_free(s->cluster_data); 756 757 migrate_del_blocker(s->migration_blocker); 758 error_free(s->migration_blocker); 759 } 760 761 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 762 { 763 int header_size, backing_filename_len, l1_size, shift, i; 764 QCowHeader header; 765 uint8_t *tmp; 766 int64_t total_size = 0; 767 char *backing_file = NULL; 768 Error *local_err = NULL; 769 int ret; 770 BlockBackend *qcow_blk; 771 char *encryptfmt = NULL; 772 QDict *options; 773 QDict *encryptopts = NULL; 774 QCryptoBlockCreateOptions *crypto_opts = NULL; 775 QCryptoBlock *crypto = NULL; 776 777 /* Read out options */ 778 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 779 BDRV_SECTOR_SIZE); 780 if (total_size == 0) { 781 error_setg(errp, "Image size is too small, cannot be zero length"); 782 ret = -EINVAL; 783 goto cleanup; 784 } 785 786 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 787 encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); 788 if (encryptfmt) { 789 if (qemu_opt_get(opts, BLOCK_OPT_ENCRYPT)) { 790 error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and " 791 BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive"); 792 ret = -EINVAL; 793 goto cleanup; 794 } 795 } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 796 encryptfmt = g_strdup("aes"); 797 } 798 799 ret = bdrv_create_file(filename, opts, &local_err); 800 if (ret < 0) { 801 error_propagate(errp, local_err); 802 goto cleanup; 803 } 804 805 qcow_blk = blk_new_open(filename, NULL, NULL, 806 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 807 &local_err); 808 if (qcow_blk == NULL) { 809 error_propagate(errp, local_err); 810 ret = -EIO; 811 goto cleanup; 812 } 813 814 blk_set_allow_write_beyond_eof(qcow_blk, true); 815 816 ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp); 817 if (ret < 0) { 818 goto exit; 819 } 820 821 memset(&header, 0, sizeof(header)); 822 header.magic = cpu_to_be32(QCOW_MAGIC); 823 header.version = cpu_to_be32(QCOW_VERSION); 824 header.size = cpu_to_be64(total_size); 825 header_size = sizeof(header); 826 backing_filename_len = 0; 827 if (backing_file) { 828 if (strcmp(backing_file, "fat:")) { 829 header.backing_file_offset = cpu_to_be64(header_size); 830 backing_filename_len = strlen(backing_file); 831 header.backing_file_size = cpu_to_be32(backing_filename_len); 832 header_size += backing_filename_len; 833 } else { 834 /* special backing file for vvfat */ 835 g_free(backing_file); 836 backing_file = NULL; 837 } 838 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 839 unmodified sectors */ 840 header.l2_bits = 12; /* 32 KB L2 tables */ 841 } else { 842 header.cluster_bits = 12; /* 4 KB clusters */ 843 header.l2_bits = 9; /* 4 KB L2 tables */ 844 } 845 header_size = (header_size + 7) & ~7; 846 shift = header.cluster_bits + header.l2_bits; 847 l1_size = (total_size + (1LL << shift) - 1) >> shift; 848 849 header.l1_table_offset = cpu_to_be64(header_size); 850 851 options = qemu_opts_to_qdict(opts, NULL); 852 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 853 QDECREF(options); 854 if (encryptfmt) { 855 if (!g_str_equal(encryptfmt, "aes")) { 856 error_setg(errp, "Unknown encryption format '%s', expected 'aes'", 857 encryptfmt); 858 ret = -EINVAL; 859 goto exit; 860 } 861 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 862 863 crypto_opts = block_crypto_create_opts_init( 864 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 865 if (!crypto_opts) { 866 ret = -EINVAL; 867 goto exit; 868 } 869 870 crypto = qcrypto_block_create(crypto_opts, "encrypt.", 871 NULL, NULL, NULL, errp); 872 if (!crypto) { 873 ret = -EINVAL; 874 goto exit; 875 } 876 } else { 877 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 878 } 879 880 /* write all the data */ 881 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 882 if (ret != sizeof(header)) { 883 goto exit; 884 } 885 886 if (backing_file) { 887 ret = blk_pwrite(qcow_blk, sizeof(header), 888 backing_file, backing_filename_len, 0); 889 if (ret != backing_filename_len) { 890 goto exit; 891 } 892 } 893 894 tmp = g_malloc0(BDRV_SECTOR_SIZE); 895 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 896 i++) { 897 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 898 tmp, BDRV_SECTOR_SIZE, 0); 899 if (ret != BDRV_SECTOR_SIZE) { 900 g_free(tmp); 901 goto exit; 902 } 903 } 904 905 g_free(tmp); 906 ret = 0; 907 exit: 908 blk_unref(qcow_blk); 909 cleanup: 910 QDECREF(encryptopts); 911 g_free(encryptfmt); 912 qcrypto_block_free(crypto); 913 qapi_free_QCryptoBlockCreateOptions(crypto_opts); 914 g_free(backing_file); 915 return ret; 916 } 917 918 static int qcow_make_empty(BlockDriverState *bs) 919 { 920 BDRVQcowState *s = bs->opaque; 921 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 922 int ret; 923 924 memset(s->l1_table, 0, l1_length); 925 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 926 l1_length) < 0) 927 return -1; 928 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, 929 PREALLOC_MODE_OFF, NULL); 930 if (ret < 0) 931 return ret; 932 933 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 934 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 935 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 936 937 return 0; 938 } 939 940 /* XXX: put compressed sectors first, then all the cluster aligned 941 tables to avoid losing bytes in alignment */ 942 static coroutine_fn int 943 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 944 uint64_t bytes, QEMUIOVector *qiov) 945 { 946 BDRVQcowState *s = bs->opaque; 947 QEMUIOVector hd_qiov; 948 struct iovec iov; 949 z_stream strm; 950 int ret, out_len; 951 uint8_t *buf, *out_buf; 952 uint64_t cluster_offset; 953 954 buf = qemu_blockalign(bs, s->cluster_size); 955 if (bytes != s->cluster_size) { 956 if (bytes > s->cluster_size || 957 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 958 { 959 qemu_vfree(buf); 960 return -EINVAL; 961 } 962 /* Zero-pad last write if image size is not cluster aligned */ 963 memset(buf + bytes, 0, s->cluster_size - bytes); 964 } 965 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 966 967 out_buf = g_malloc(s->cluster_size); 968 969 /* best compression, small window, no zlib header */ 970 memset(&strm, 0, sizeof(strm)); 971 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 972 Z_DEFLATED, -12, 973 9, Z_DEFAULT_STRATEGY); 974 if (ret != 0) { 975 ret = -EINVAL; 976 goto fail; 977 } 978 979 strm.avail_in = s->cluster_size; 980 strm.next_in = (uint8_t *)buf; 981 strm.avail_out = s->cluster_size; 982 strm.next_out = out_buf; 983 984 ret = deflate(&strm, Z_FINISH); 985 if (ret != Z_STREAM_END && ret != Z_OK) { 986 deflateEnd(&strm); 987 ret = -EINVAL; 988 goto fail; 989 } 990 out_len = strm.next_out - out_buf; 991 992 deflateEnd(&strm); 993 994 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 995 /* could not compress: write normal cluster */ 996 ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS, 997 bytes >> BDRV_SECTOR_BITS, qiov); 998 if (ret < 0) { 999 goto fail; 1000 } 1001 goto success; 1002 } 1003 qemu_co_mutex_lock(&s->lock); 1004 cluster_offset = get_cluster_offset(bs, offset, 2, out_len, 0, 0); 1005 qemu_co_mutex_unlock(&s->lock); 1006 if (cluster_offset == 0) { 1007 ret = -EIO; 1008 goto fail; 1009 } 1010 cluster_offset &= s->cluster_offset_mask; 1011 1012 iov = (struct iovec) { 1013 .iov_base = out_buf, 1014 .iov_len = out_len, 1015 }; 1016 qemu_iovec_init_external(&hd_qiov, &iov, 1); 1017 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1018 if (ret < 0) { 1019 goto fail; 1020 } 1021 success: 1022 ret = 0; 1023 fail: 1024 qemu_vfree(buf); 1025 g_free(out_buf); 1026 return ret; 1027 } 1028 1029 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1030 { 1031 BDRVQcowState *s = bs->opaque; 1032 bdi->cluster_size = s->cluster_size; 1033 return 0; 1034 } 1035 1036 static QemuOptsList qcow_create_opts = { 1037 .name = "qcow-create-opts", 1038 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1039 .desc = { 1040 { 1041 .name = BLOCK_OPT_SIZE, 1042 .type = QEMU_OPT_SIZE, 1043 .help = "Virtual disk size" 1044 }, 1045 { 1046 .name = BLOCK_OPT_BACKING_FILE, 1047 .type = QEMU_OPT_STRING, 1048 .help = "File name of a base image" 1049 }, 1050 { 1051 .name = BLOCK_OPT_ENCRYPT, 1052 .type = QEMU_OPT_BOOL, 1053 .help = "Encrypt the image with format 'aes'. (Deprecated " 1054 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1055 }, 1056 { 1057 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1058 .type = QEMU_OPT_STRING, 1059 .help = "Encrypt the image, format choices: 'aes'", 1060 }, 1061 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1062 { /* end of list */ } 1063 } 1064 }; 1065 1066 static BlockDriver bdrv_qcow = { 1067 .format_name = "qcow", 1068 .instance_size = sizeof(BDRVQcowState), 1069 .bdrv_probe = qcow_probe, 1070 .bdrv_open = qcow_open, 1071 .bdrv_close = qcow_close, 1072 .bdrv_child_perm = bdrv_format_default_perms, 1073 .bdrv_reopen_prepare = qcow_reopen_prepare, 1074 .bdrv_create = qcow_create, 1075 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1076 .supports_backing = true, 1077 1078 .bdrv_co_readv = qcow_co_readv, 1079 .bdrv_co_writev = qcow_co_writev, 1080 .bdrv_co_get_block_status = qcow_co_get_block_status, 1081 1082 .bdrv_make_empty = qcow_make_empty, 1083 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1084 .bdrv_get_info = qcow_get_info, 1085 1086 .create_opts = &qcow_create_opts, 1087 }; 1088 1089 static void bdrv_qcow_init(void) 1090 { 1091 bdrv_register(&bdrv_qcow); 1092 } 1093 1094 block_init(bdrv_qcow_init); 1095