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 25 #include "qemu/osdep.h" 26 #include "qapi/error.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/option.h" 32 #include "qemu/bswap.h" 33 #include <zlib.h> 34 #include "qapi/qmp/qdict.h" 35 #include "qapi/qmp/qstring.h" 36 #include "qapi/qobject-input-visitor.h" 37 #include "qapi/qapi-visit-block-core.h" 38 #include "crypto/block.h" 39 #include "migration/blocker.h" 40 #include "block/crypto.h" 41 42 /**************************************************************/ 43 /* QEMU COW block driver with compression and encryption support */ 44 45 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 46 #define QCOW_VERSION 1 47 48 #define QCOW_CRYPT_NONE 0 49 #define QCOW_CRYPT_AES 1 50 51 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 52 53 typedef struct QCowHeader { 54 uint32_t magic; 55 uint32_t version; 56 uint64_t backing_file_offset; 57 uint32_t backing_file_size; 58 uint32_t mtime; 59 uint64_t size; /* in bytes */ 60 uint8_t cluster_bits; 61 uint8_t l2_bits; 62 uint16_t padding; 63 uint32_t crypt_method; 64 uint64_t l1_table_offset; 65 } QEMU_PACKED QCowHeader; 66 67 #define L2_CACHE_SIZE 16 68 69 typedef struct BDRVQcowState { 70 int cluster_bits; 71 int cluster_size; 72 int cluster_sectors; 73 int l2_bits; 74 int l2_size; 75 unsigned int l1_size; 76 uint64_t cluster_offset_mask; 77 uint64_t l1_table_offset; 78 uint64_t *l1_table; 79 uint64_t *l2_cache; 80 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 81 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 82 uint8_t *cluster_cache; 83 uint8_t *cluster_data; 84 uint64_t cluster_cache_offset; 85 QCryptoBlock *crypto; /* Disk encryption format driver */ 86 uint32_t crypt_method_header; 87 CoMutex lock; 88 Error *migration_blocker; 89 } BDRVQcowState; 90 91 static QemuOptsList qcow_create_opts; 92 93 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 94 95 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 96 { 97 const QCowHeader *cow_header = (const void *)buf; 98 99 if (buf_size >= sizeof(QCowHeader) && 100 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 101 be32_to_cpu(cow_header->version) == QCOW_VERSION) 102 return 100; 103 else 104 return 0; 105 } 106 107 static QemuOptsList qcow_runtime_opts = { 108 .name = "qcow", 109 .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head), 110 .desc = { 111 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 112 { /* end of list */ } 113 }, 114 }; 115 116 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 117 Error **errp) 118 { 119 BDRVQcowState *s = bs->opaque; 120 unsigned int len, i, shift; 121 int ret; 122 QCowHeader header; 123 Error *local_err = NULL; 124 QCryptoBlockOpenOptions *crypto_opts = NULL; 125 unsigned int cflags = 0; 126 QDict *encryptopts = NULL; 127 const char *encryptfmt; 128 129 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 130 encryptfmt = qdict_get_try_str(encryptopts, "format"); 131 132 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 133 false, errp); 134 if (!bs->file) { 135 ret = -EINVAL; 136 goto fail; 137 } 138 139 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 140 if (ret < 0) { 141 goto fail; 142 } 143 be32_to_cpus(&header.magic); 144 be32_to_cpus(&header.version); 145 be64_to_cpus(&header.backing_file_offset); 146 be32_to_cpus(&header.backing_file_size); 147 be32_to_cpus(&header.mtime); 148 be64_to_cpus(&header.size); 149 be32_to_cpus(&header.crypt_method); 150 be64_to_cpus(&header.l1_table_offset); 151 152 if (header.magic != QCOW_MAGIC) { 153 error_setg(errp, "Image not in qcow format"); 154 ret = -EINVAL; 155 goto fail; 156 } 157 if (header.version != QCOW_VERSION) { 158 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 159 ret = -ENOTSUP; 160 goto fail; 161 } 162 163 if (header.size <= 1) { 164 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 165 ret = -EINVAL; 166 goto fail; 167 } 168 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 169 error_setg(errp, "Cluster size must be between 512 and 64k"); 170 ret = -EINVAL; 171 goto fail; 172 } 173 174 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 175 * so bytes = num_entries << 3. */ 176 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 177 error_setg(errp, "L2 table size must be between 512 and 64k"); 178 ret = -EINVAL; 179 goto fail; 180 } 181 182 s->crypt_method_header = header.crypt_method; 183 if (s->crypt_method_header) { 184 if (bdrv_uses_whitelist() && 185 s->crypt_method_header == QCOW_CRYPT_AES) { 186 error_setg(errp, 187 "Use of AES-CBC encrypted qcow images is no longer " 188 "supported in system emulators"); 189 error_append_hint(errp, 190 "You can use 'qemu-img convert' to convert your " 191 "image to an alternative supported format, such " 192 "as unencrypted qcow, or raw with the LUKS " 193 "format instead.\n"); 194 ret = -ENOSYS; 195 goto fail; 196 } 197 if (s->crypt_method_header == QCOW_CRYPT_AES) { 198 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 199 error_setg(errp, 200 "Header reported 'aes' encryption format but " 201 "options specify '%s'", encryptfmt); 202 ret = -EINVAL; 203 goto fail; 204 } 205 qdict_del(encryptopts, "format"); 206 crypto_opts = block_crypto_open_opts_init( 207 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 208 if (!crypto_opts) { 209 ret = -EINVAL; 210 goto fail; 211 } 212 213 if (flags & BDRV_O_NO_IO) { 214 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 215 } 216 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 217 NULL, NULL, cflags, errp); 218 if (!s->crypto) { 219 ret = -EINVAL; 220 goto fail; 221 } 222 } else { 223 error_setg(errp, "invalid encryption method in qcow header"); 224 ret = -EINVAL; 225 goto fail; 226 } 227 bs->encrypted = true; 228 } else { 229 if (encryptfmt) { 230 error_setg(errp, "No encryption in image header, but options " 231 "specified format '%s'", encryptfmt); 232 ret = -EINVAL; 233 goto fail; 234 } 235 } 236 s->cluster_bits = header.cluster_bits; 237 s->cluster_size = 1 << s->cluster_bits; 238 s->cluster_sectors = 1 << (s->cluster_bits - 9); 239 s->l2_bits = header.l2_bits; 240 s->l2_size = 1 << s->l2_bits; 241 bs->total_sectors = header.size / 512; 242 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 243 244 /* read the level 1 table */ 245 shift = s->cluster_bits + s->l2_bits; 246 if (header.size > UINT64_MAX - (1LL << shift)) { 247 error_setg(errp, "Image too large"); 248 ret = -EINVAL; 249 goto fail; 250 } else { 251 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 252 if (l1_size > INT_MAX / sizeof(uint64_t)) { 253 error_setg(errp, "Image too large"); 254 ret = -EINVAL; 255 goto fail; 256 } 257 s->l1_size = l1_size; 258 } 259 260 s->l1_table_offset = header.l1_table_offset; 261 s->l1_table = g_try_new(uint64_t, s->l1_size); 262 if (s->l1_table == NULL) { 263 error_setg(errp, "Could not allocate memory for L1 table"); 264 ret = -ENOMEM; 265 goto fail; 266 } 267 268 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 269 s->l1_size * sizeof(uint64_t)); 270 if (ret < 0) { 271 goto fail; 272 } 273 274 for(i = 0;i < s->l1_size; i++) { 275 be64_to_cpus(&s->l1_table[i]); 276 } 277 278 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 279 s->l2_cache = 280 qemu_try_blockalign(bs->file->bs, 281 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 282 if (s->l2_cache == NULL) { 283 error_setg(errp, "Could not allocate L2 table cache"); 284 ret = -ENOMEM; 285 goto fail; 286 } 287 s->cluster_cache = g_malloc(s->cluster_size); 288 s->cluster_data = g_malloc(s->cluster_size); 289 s->cluster_cache_offset = -1; 290 291 /* read the backing file name */ 292 if (header.backing_file_offset != 0) { 293 len = header.backing_file_size; 294 if (len > 1023 || len >= sizeof(bs->backing_file)) { 295 error_setg(errp, "Backing file name too long"); 296 ret = -EINVAL; 297 goto fail; 298 } 299 ret = bdrv_pread(bs->file, header.backing_file_offset, 300 bs->backing_file, len); 301 if (ret < 0) { 302 goto fail; 303 } 304 bs->backing_file[len] = '\0'; 305 } 306 307 /* Disable migration when qcow images are used */ 308 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 309 "does not support live migration", 310 bdrv_get_device_or_node_name(bs)); 311 ret = migrate_add_blocker(s->migration_blocker, &local_err); 312 if (local_err) { 313 error_propagate(errp, local_err); 314 error_free(s->migration_blocker); 315 goto fail; 316 } 317 318 QDECREF(encryptopts); 319 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 320 qemu_co_mutex_init(&s->lock); 321 return 0; 322 323 fail: 324 g_free(s->l1_table); 325 qemu_vfree(s->l2_cache); 326 g_free(s->cluster_cache); 327 g_free(s->cluster_data); 328 qcrypto_block_free(s->crypto); 329 QDECREF(encryptopts); 330 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 331 return ret; 332 } 333 334 335 /* We have nothing to do for QCOW reopen, stubs just return 336 * success */ 337 static int qcow_reopen_prepare(BDRVReopenState *state, 338 BlockReopenQueue *queue, Error **errp) 339 { 340 return 0; 341 } 342 343 344 /* 'allocate' is: 345 * 346 * 0 to not allocate. 347 * 348 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 349 * 'n_end') 350 * 351 * 2 to allocate a compressed cluster of size 352 * 'compressed_size'. 'compressed_size' must be > 0 and < 353 * cluster_size 354 * 355 * return 0 if not allocated, 1 if *result is assigned, and negative 356 * errno on failure. 357 */ 358 static int get_cluster_offset(BlockDriverState *bs, 359 uint64_t offset, int allocate, 360 int compressed_size, 361 int n_start, int n_end, uint64_t *result) 362 { 363 BDRVQcowState *s = bs->opaque; 364 int min_index, i, j, l1_index, l2_index, ret; 365 int64_t l2_offset; 366 uint64_t *l2_table, cluster_offset, tmp; 367 uint32_t min_count; 368 int new_l2_table; 369 370 *result = 0; 371 l1_index = offset >> (s->l2_bits + s->cluster_bits); 372 l2_offset = s->l1_table[l1_index]; 373 new_l2_table = 0; 374 if (!l2_offset) { 375 if (!allocate) 376 return 0; 377 /* allocate a new l2 entry */ 378 l2_offset = bdrv_getlength(bs->file->bs); 379 if (l2_offset < 0) { 380 return l2_offset; 381 } 382 /* round to cluster size */ 383 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 384 /* update the L1 entry */ 385 s->l1_table[l1_index] = l2_offset; 386 tmp = cpu_to_be64(l2_offset); 387 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 388 ret = bdrv_pwrite_sync(bs->file, 389 s->l1_table_offset + l1_index * sizeof(tmp), 390 &tmp, sizeof(tmp)); 391 if (ret < 0) { 392 return ret; 393 } 394 new_l2_table = 1; 395 } 396 for(i = 0; i < L2_CACHE_SIZE; i++) { 397 if (l2_offset == s->l2_cache_offsets[i]) { 398 /* increment the hit count */ 399 if (++s->l2_cache_counts[i] == 0xffffffff) { 400 for(j = 0; j < L2_CACHE_SIZE; j++) { 401 s->l2_cache_counts[j] >>= 1; 402 } 403 } 404 l2_table = s->l2_cache + (i << s->l2_bits); 405 goto found; 406 } 407 } 408 /* not found: load a new entry in the least used one */ 409 min_index = 0; 410 min_count = 0xffffffff; 411 for(i = 0; i < L2_CACHE_SIZE; i++) { 412 if (s->l2_cache_counts[i] < min_count) { 413 min_count = s->l2_cache_counts[i]; 414 min_index = i; 415 } 416 } 417 l2_table = s->l2_cache + (min_index << s->l2_bits); 418 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); 419 if (new_l2_table) { 420 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 421 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 422 s->l2_size * sizeof(uint64_t)); 423 if (ret < 0) { 424 return ret; 425 } 426 } else { 427 ret = bdrv_pread(bs->file, l2_offset, l2_table, 428 s->l2_size * sizeof(uint64_t)); 429 if (ret < 0) { 430 return ret; 431 } 432 } 433 s->l2_cache_offsets[min_index] = l2_offset; 434 s->l2_cache_counts[min_index] = 1; 435 found: 436 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 437 cluster_offset = be64_to_cpu(l2_table[l2_index]); 438 if (!cluster_offset || 439 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 440 if (!allocate) 441 return 0; 442 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 443 /* allocate a new cluster */ 444 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 445 (n_end - n_start) < s->cluster_sectors) { 446 /* if the cluster is already compressed, we must 447 decompress it in the case it is not completely 448 overwritten */ 449 if (decompress_cluster(bs, cluster_offset) < 0) { 450 return -EIO; 451 } 452 cluster_offset = bdrv_getlength(bs->file->bs); 453 if ((int64_t) cluster_offset < 0) { 454 return cluster_offset; 455 } 456 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 457 /* write the cluster content */ 458 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 459 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 460 s->cluster_size); 461 if (ret < 0) { 462 return ret; 463 } 464 } else { 465 cluster_offset = bdrv_getlength(bs->file->bs); 466 if ((int64_t) cluster_offset < 0) { 467 return cluster_offset; 468 } 469 if (allocate == 1) { 470 /* round to cluster size */ 471 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 472 if (cluster_offset + s->cluster_size > INT64_MAX) { 473 return -E2BIG; 474 } 475 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 476 PREALLOC_MODE_OFF, NULL); 477 if (ret < 0) { 478 return ret; 479 } 480 /* if encrypted, we must initialize the cluster 481 content which won't be written */ 482 if (bs->encrypted && 483 (n_end - n_start) < s->cluster_sectors) { 484 uint64_t start_sect; 485 assert(s->crypto); 486 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 487 for(i = 0; i < s->cluster_sectors; i++) { 488 if (i < n_start || i >= n_end) { 489 memset(s->cluster_data, 0x00, 512); 490 if (qcrypto_block_encrypt(s->crypto, 491 (start_sect + i) * 492 BDRV_SECTOR_SIZE, 493 s->cluster_data, 494 BDRV_SECTOR_SIZE, 495 NULL) < 0) { 496 return -EIO; 497 } 498 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 499 ret = bdrv_pwrite(bs->file, 500 cluster_offset + i * 512, 501 s->cluster_data, 512); 502 if (ret < 0) { 503 return ret; 504 } 505 } 506 } 507 } 508 } else if (allocate == 2) { 509 cluster_offset |= QCOW_OFLAG_COMPRESSED | 510 (uint64_t)compressed_size << (63 - s->cluster_bits); 511 } 512 } 513 /* update L2 table */ 514 tmp = cpu_to_be64(cluster_offset); 515 l2_table[l2_index] = tmp; 516 if (allocate == 2) { 517 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); 518 } else { 519 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); 520 } 521 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 522 &tmp, sizeof(tmp)); 523 if (ret < 0) { 524 return ret; 525 } 526 } 527 *result = cluster_offset; 528 return 1; 529 } 530 531 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs, 532 bool want_zero, 533 int64_t offset, int64_t bytes, 534 int64_t *pnum, int64_t *map, 535 BlockDriverState **file) 536 { 537 BDRVQcowState *s = bs->opaque; 538 int index_in_cluster, ret; 539 int64_t n; 540 uint64_t cluster_offset; 541 542 qemu_co_mutex_lock(&s->lock); 543 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 544 qemu_co_mutex_unlock(&s->lock); 545 if (ret < 0) { 546 return ret; 547 } 548 index_in_cluster = offset & (s->cluster_size - 1); 549 n = s->cluster_size - index_in_cluster; 550 if (n > bytes) { 551 n = bytes; 552 } 553 *pnum = n; 554 if (!cluster_offset) { 555 return 0; 556 } 557 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 558 return BDRV_BLOCK_DATA; 559 } 560 *map = cluster_offset | index_in_cluster; 561 *file = bs->file->bs; 562 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 563 } 564 565 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 566 const uint8_t *buf, int buf_size) 567 { 568 z_stream strm1, *strm = &strm1; 569 int ret, out_len; 570 571 memset(strm, 0, sizeof(*strm)); 572 573 strm->next_in = (uint8_t *)buf; 574 strm->avail_in = buf_size; 575 strm->next_out = out_buf; 576 strm->avail_out = out_buf_size; 577 578 ret = inflateInit2(strm, -12); 579 if (ret != Z_OK) 580 return -1; 581 ret = inflate(strm, Z_FINISH); 582 out_len = strm->next_out - out_buf; 583 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 584 out_len != out_buf_size) { 585 inflateEnd(strm); 586 return -1; 587 } 588 inflateEnd(strm); 589 return 0; 590 } 591 592 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 593 { 594 BDRVQcowState *s = bs->opaque; 595 int ret, csize; 596 uint64_t coffset; 597 598 coffset = cluster_offset & s->cluster_offset_mask; 599 if (s->cluster_cache_offset != coffset) { 600 csize = cluster_offset >> (63 - s->cluster_bits); 601 csize &= (s->cluster_size - 1); 602 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 603 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 604 if (ret != csize) 605 return -1; 606 if (decompress_buffer(s->cluster_cache, s->cluster_size, 607 s->cluster_data, csize) < 0) { 608 return -1; 609 } 610 s->cluster_cache_offset = coffset; 611 } 612 return 0; 613 } 614 615 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 616 int nb_sectors, QEMUIOVector *qiov) 617 { 618 BDRVQcowState *s = bs->opaque; 619 int index_in_cluster; 620 int ret = 0, n; 621 uint64_t cluster_offset; 622 struct iovec hd_iov; 623 QEMUIOVector hd_qiov; 624 uint8_t *buf; 625 void *orig_buf; 626 627 if (qiov->niov > 1) { 628 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 629 if (buf == NULL) { 630 return -ENOMEM; 631 } 632 } else { 633 orig_buf = NULL; 634 buf = (uint8_t *)qiov->iov->iov_base; 635 } 636 637 qemu_co_mutex_lock(&s->lock); 638 639 while (nb_sectors != 0) { 640 /* prepare next request */ 641 ret = get_cluster_offset(bs, sector_num << 9, 642 0, 0, 0, 0, &cluster_offset); 643 if (ret < 0) { 644 break; 645 } 646 index_in_cluster = sector_num & (s->cluster_sectors - 1); 647 n = s->cluster_sectors - index_in_cluster; 648 if (n > nb_sectors) { 649 n = nb_sectors; 650 } 651 652 if (!cluster_offset) { 653 if (bs->backing) { 654 /* read from the base image */ 655 hd_iov.iov_base = (void *)buf; 656 hd_iov.iov_len = n * 512; 657 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 658 qemu_co_mutex_unlock(&s->lock); 659 /* qcow2 emits this on bs->file instead of bs->backing */ 660 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 661 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 662 qemu_co_mutex_lock(&s->lock); 663 if (ret < 0) { 664 break; 665 } 666 } else { 667 /* Note: in this case, no need to wait */ 668 memset(buf, 0, 512 * n); 669 } 670 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 671 /* add AIO support for compressed blocks ? */ 672 if (decompress_cluster(bs, cluster_offset) < 0) { 673 ret = -EIO; 674 break; 675 } 676 memcpy(buf, 677 s->cluster_cache + index_in_cluster * 512, 512 * n); 678 } else { 679 if ((cluster_offset & 511) != 0) { 680 ret = -EIO; 681 break; 682 } 683 hd_iov.iov_base = (void *)buf; 684 hd_iov.iov_len = n * 512; 685 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 686 qemu_co_mutex_unlock(&s->lock); 687 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 688 ret = bdrv_co_readv(bs->file, 689 (cluster_offset >> 9) + index_in_cluster, 690 n, &hd_qiov); 691 qemu_co_mutex_lock(&s->lock); 692 if (ret < 0) { 693 break; 694 } 695 if (bs->encrypted) { 696 assert(s->crypto); 697 if (qcrypto_block_decrypt(s->crypto, 698 sector_num * BDRV_SECTOR_SIZE, buf, 699 n * BDRV_SECTOR_SIZE, NULL) < 0) { 700 ret = -EIO; 701 break; 702 } 703 } 704 } 705 ret = 0; 706 707 nb_sectors -= n; 708 sector_num += n; 709 buf += n * 512; 710 } 711 712 qemu_co_mutex_unlock(&s->lock); 713 714 if (qiov->niov > 1) { 715 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 716 qemu_vfree(orig_buf); 717 } 718 719 return ret; 720 } 721 722 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 723 int nb_sectors, QEMUIOVector *qiov) 724 { 725 BDRVQcowState *s = bs->opaque; 726 int index_in_cluster; 727 uint64_t cluster_offset; 728 int ret = 0, n; 729 struct iovec hd_iov; 730 QEMUIOVector hd_qiov; 731 uint8_t *buf; 732 void *orig_buf; 733 734 s->cluster_cache_offset = -1; /* disable compressed cache */ 735 736 /* We must always copy the iov when encrypting, so we 737 * don't modify the original data buffer during encryption */ 738 if (bs->encrypted || qiov->niov > 1) { 739 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 740 if (buf == NULL) { 741 return -ENOMEM; 742 } 743 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 744 } else { 745 orig_buf = NULL; 746 buf = (uint8_t *)qiov->iov->iov_base; 747 } 748 749 qemu_co_mutex_lock(&s->lock); 750 751 while (nb_sectors != 0) { 752 753 index_in_cluster = sector_num & (s->cluster_sectors - 1); 754 n = s->cluster_sectors - index_in_cluster; 755 if (n > nb_sectors) { 756 n = nb_sectors; 757 } 758 ret = get_cluster_offset(bs, sector_num << 9, 1, 0, 759 index_in_cluster, 760 index_in_cluster + n, &cluster_offset); 761 if (ret < 0) { 762 break; 763 } 764 if (!cluster_offset || (cluster_offset & 511) != 0) { 765 ret = -EIO; 766 break; 767 } 768 if (bs->encrypted) { 769 assert(s->crypto); 770 if (qcrypto_block_encrypt(s->crypto, sector_num * BDRV_SECTOR_SIZE, 771 buf, n * BDRV_SECTOR_SIZE, NULL) < 0) { 772 ret = -EIO; 773 break; 774 } 775 } 776 777 hd_iov.iov_base = (void *)buf; 778 hd_iov.iov_len = n * 512; 779 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 780 qemu_co_mutex_unlock(&s->lock); 781 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 782 ret = bdrv_co_writev(bs->file, 783 (cluster_offset >> 9) + index_in_cluster, 784 n, &hd_qiov); 785 qemu_co_mutex_lock(&s->lock); 786 if (ret < 0) { 787 break; 788 } 789 ret = 0; 790 791 nb_sectors -= n; 792 sector_num += n; 793 buf += n * 512; 794 } 795 qemu_co_mutex_unlock(&s->lock); 796 797 qemu_vfree(orig_buf); 798 799 return ret; 800 } 801 802 static void qcow_close(BlockDriverState *bs) 803 { 804 BDRVQcowState *s = bs->opaque; 805 806 qcrypto_block_free(s->crypto); 807 s->crypto = NULL; 808 g_free(s->l1_table); 809 qemu_vfree(s->l2_cache); 810 g_free(s->cluster_cache); 811 g_free(s->cluster_data); 812 813 migrate_del_blocker(s->migration_blocker); 814 error_free(s->migration_blocker); 815 } 816 817 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts, 818 Error **errp) 819 { 820 BlockdevCreateOptionsQcow *qcow_opts; 821 int header_size, backing_filename_len, l1_size, shift, i; 822 QCowHeader header; 823 uint8_t *tmp; 824 int64_t total_size = 0; 825 int ret; 826 BlockDriverState *bs; 827 BlockBackend *qcow_blk; 828 QCryptoBlock *crypto = NULL; 829 830 assert(opts->driver == BLOCKDEV_DRIVER_QCOW); 831 qcow_opts = &opts->u.qcow; 832 833 /* Sanity checks */ 834 total_size = qcow_opts->size; 835 if (total_size == 0) { 836 error_setg(errp, "Image size is too small, cannot be zero length"); 837 return -EINVAL; 838 } 839 840 if (qcow_opts->has_encrypt && 841 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) 842 { 843 error_setg(errp, "Unsupported encryption format"); 844 return -EINVAL; 845 } 846 847 /* Create BlockBackend to write to the image */ 848 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp); 849 if (bs == NULL) { 850 return -EIO; 851 } 852 853 qcow_blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 854 ret = blk_insert_bs(qcow_blk, bs, errp); 855 if (ret < 0) { 856 goto exit; 857 } 858 blk_set_allow_write_beyond_eof(qcow_blk, true); 859 860 /* Create image format */ 861 ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp); 862 if (ret < 0) { 863 goto exit; 864 } 865 866 memset(&header, 0, sizeof(header)); 867 header.magic = cpu_to_be32(QCOW_MAGIC); 868 header.version = cpu_to_be32(QCOW_VERSION); 869 header.size = cpu_to_be64(total_size); 870 header_size = sizeof(header); 871 backing_filename_len = 0; 872 if (qcow_opts->has_backing_file) { 873 if (strcmp(qcow_opts->backing_file, "fat:")) { 874 header.backing_file_offset = cpu_to_be64(header_size); 875 backing_filename_len = strlen(qcow_opts->backing_file); 876 header.backing_file_size = cpu_to_be32(backing_filename_len); 877 header_size += backing_filename_len; 878 } else { 879 /* special backing file for vvfat */ 880 qcow_opts->has_backing_file = false; 881 } 882 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 883 unmodified sectors */ 884 header.l2_bits = 12; /* 32 KB L2 tables */ 885 } else { 886 header.cluster_bits = 12; /* 4 KB clusters */ 887 header.l2_bits = 9; /* 4 KB L2 tables */ 888 } 889 header_size = (header_size + 7) & ~7; 890 shift = header.cluster_bits + header.l2_bits; 891 l1_size = (total_size + (1LL << shift) - 1) >> shift; 892 893 header.l1_table_offset = cpu_to_be64(header_size); 894 895 if (qcow_opts->has_encrypt) { 896 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 897 898 crypto = qcrypto_block_create(qcow_opts->encrypt, "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 (qcow_opts->has_backing_file) { 915 ret = blk_pwrite(qcow_blk, sizeof(header), 916 qcow_opts->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 qcrypto_block_free(crypto); 938 return ret; 939 } 940 941 static int coroutine_fn qcow_co_create_opts(const char *filename, 942 QemuOpts *opts, Error **errp) 943 { 944 BlockdevCreateOptions *create_options = NULL; 945 BlockDriverState *bs = NULL; 946 QDict *qdict = NULL; 947 QObject *qobj; 948 Visitor *v; 949 const char *val; 950 Error *local_err = NULL; 951 int ret; 952 953 static const QDictRenames opt_renames[] = { 954 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 955 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 956 { NULL, NULL }, 957 }; 958 959 /* Parse options and convert legacy syntax */ 960 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); 961 962 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 963 if (val && !strcmp(val, "on")) { 964 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 965 } else if (val && !strcmp(val, "off")) { 966 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 967 } 968 969 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 970 if (val && !strcmp(val, "aes")) { 971 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 972 } 973 974 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 975 ret = -EINVAL; 976 goto fail; 977 } 978 979 /* Create and open the file (protocol layer) */ 980 ret = bdrv_create_file(filename, opts, &local_err); 981 if (ret < 0) { 982 error_propagate(errp, local_err); 983 goto fail; 984 } 985 986 bs = bdrv_open(filename, NULL, NULL, 987 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 988 if (bs == NULL) { 989 ret = -EIO; 990 goto fail; 991 } 992 993 /* Now get the QAPI type BlockdevCreateOptions */ 994 qdict_put_str(qdict, "driver", "qcow"); 995 qdict_put_str(qdict, "file", bs->node_name); 996 997 qobj = qdict_crumple(qdict, errp); 998 QDECREF(qdict); 999 qdict = qobject_to_qdict(qobj); 1000 if (qdict == NULL) { 1001 ret = -EINVAL; 1002 goto fail; 1003 } 1004 1005 v = qobject_input_visitor_new_keyval(QOBJECT(qdict)); 1006 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 1007 visit_free(v); 1008 1009 if (local_err) { 1010 error_propagate(errp, local_err); 1011 ret = -EINVAL; 1012 goto fail; 1013 } 1014 1015 /* Silently round up size */ 1016 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); 1017 create_options->u.qcow.size = 1018 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); 1019 1020 /* Create the qcow image (format layer) */ 1021 ret = qcow_co_create(create_options, errp); 1022 if (ret < 0) { 1023 goto fail; 1024 } 1025 1026 ret = 0; 1027 fail: 1028 QDECREF(qdict); 1029 bdrv_unref(bs); 1030 qapi_free_BlockdevCreateOptions(create_options); 1031 return ret; 1032 } 1033 1034 static int qcow_make_empty(BlockDriverState *bs) 1035 { 1036 BDRVQcowState *s = bs->opaque; 1037 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 1038 int ret; 1039 1040 memset(s->l1_table, 0, l1_length); 1041 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 1042 l1_length) < 0) 1043 return -1; 1044 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, 1045 PREALLOC_MODE_OFF, NULL); 1046 if (ret < 0) 1047 return ret; 1048 1049 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 1050 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 1051 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 1052 1053 return 0; 1054 } 1055 1056 /* XXX: put compressed sectors first, then all the cluster aligned 1057 tables to avoid losing bytes in alignment */ 1058 static coroutine_fn int 1059 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 1060 uint64_t bytes, QEMUIOVector *qiov) 1061 { 1062 BDRVQcowState *s = bs->opaque; 1063 QEMUIOVector hd_qiov; 1064 struct iovec iov; 1065 z_stream strm; 1066 int ret, out_len; 1067 uint8_t *buf, *out_buf; 1068 uint64_t cluster_offset; 1069 1070 buf = qemu_blockalign(bs, s->cluster_size); 1071 if (bytes != s->cluster_size) { 1072 if (bytes > s->cluster_size || 1073 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 1074 { 1075 qemu_vfree(buf); 1076 return -EINVAL; 1077 } 1078 /* Zero-pad last write if image size is not cluster aligned */ 1079 memset(buf + bytes, 0, s->cluster_size - bytes); 1080 } 1081 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 1082 1083 out_buf = g_malloc(s->cluster_size); 1084 1085 /* best compression, small window, no zlib header */ 1086 memset(&strm, 0, sizeof(strm)); 1087 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 1088 Z_DEFLATED, -12, 1089 9, Z_DEFAULT_STRATEGY); 1090 if (ret != 0) { 1091 ret = -EINVAL; 1092 goto fail; 1093 } 1094 1095 strm.avail_in = s->cluster_size; 1096 strm.next_in = (uint8_t *)buf; 1097 strm.avail_out = s->cluster_size; 1098 strm.next_out = out_buf; 1099 1100 ret = deflate(&strm, Z_FINISH); 1101 if (ret != Z_STREAM_END && ret != Z_OK) { 1102 deflateEnd(&strm); 1103 ret = -EINVAL; 1104 goto fail; 1105 } 1106 out_len = strm.next_out - out_buf; 1107 1108 deflateEnd(&strm); 1109 1110 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1111 /* could not compress: write normal cluster */ 1112 ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS, 1113 bytes >> BDRV_SECTOR_BITS, qiov); 1114 if (ret < 0) { 1115 goto fail; 1116 } 1117 goto success; 1118 } 1119 qemu_co_mutex_lock(&s->lock); 1120 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); 1121 qemu_co_mutex_unlock(&s->lock); 1122 if (ret < 0) { 1123 goto fail; 1124 } 1125 if (cluster_offset == 0) { 1126 ret = -EIO; 1127 goto fail; 1128 } 1129 cluster_offset &= s->cluster_offset_mask; 1130 1131 iov = (struct iovec) { 1132 .iov_base = out_buf, 1133 .iov_len = out_len, 1134 }; 1135 qemu_iovec_init_external(&hd_qiov, &iov, 1); 1136 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 1137 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1138 if (ret < 0) { 1139 goto fail; 1140 } 1141 success: 1142 ret = 0; 1143 fail: 1144 qemu_vfree(buf); 1145 g_free(out_buf); 1146 return ret; 1147 } 1148 1149 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1150 { 1151 BDRVQcowState *s = bs->opaque; 1152 bdi->cluster_size = s->cluster_size; 1153 return 0; 1154 } 1155 1156 static QemuOptsList qcow_create_opts = { 1157 .name = "qcow-create-opts", 1158 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1159 .desc = { 1160 { 1161 .name = BLOCK_OPT_SIZE, 1162 .type = QEMU_OPT_SIZE, 1163 .help = "Virtual disk size" 1164 }, 1165 { 1166 .name = BLOCK_OPT_BACKING_FILE, 1167 .type = QEMU_OPT_STRING, 1168 .help = "File name of a base image" 1169 }, 1170 { 1171 .name = BLOCK_OPT_ENCRYPT, 1172 .type = QEMU_OPT_BOOL, 1173 .help = "Encrypt the image with format 'aes'. (Deprecated " 1174 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1175 }, 1176 { 1177 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1178 .type = QEMU_OPT_STRING, 1179 .help = "Encrypt the image, format choices: 'aes'", 1180 }, 1181 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1182 { /* end of list */ } 1183 } 1184 }; 1185 1186 static BlockDriver bdrv_qcow = { 1187 .format_name = "qcow", 1188 .instance_size = sizeof(BDRVQcowState), 1189 .bdrv_probe = qcow_probe, 1190 .bdrv_open = qcow_open, 1191 .bdrv_close = qcow_close, 1192 .bdrv_child_perm = bdrv_format_default_perms, 1193 .bdrv_reopen_prepare = qcow_reopen_prepare, 1194 .bdrv_co_create = qcow_co_create, 1195 .bdrv_co_create_opts = qcow_co_create_opts, 1196 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1197 .supports_backing = true, 1198 1199 .bdrv_co_readv = qcow_co_readv, 1200 .bdrv_co_writev = qcow_co_writev, 1201 .bdrv_co_block_status = qcow_co_block_status, 1202 1203 .bdrv_make_empty = qcow_make_empty, 1204 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1205 .bdrv_get_info = qcow_get_info, 1206 1207 .create_opts = &qcow_create_opts, 1208 }; 1209 1210 static void bdrv_qcow_init(void) 1211 { 1212 bdrv_register(&bdrv_qcow); 1213 } 1214 1215 block_init(bdrv_qcow_init); 1216