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 "block/qdict.h" 30 #include "sysemu/block-backend.h" 31 #include "qemu/module.h" 32 #include "qemu/option.h" 33 #include "qemu/bswap.h" 34 #include <zlib.h> 35 #include "qapi/qmp/qdict.h" 36 #include "qapi/qmp/qstring.h" 37 #include "qapi/qobject-input-visitor.h" 38 #include "qapi/qapi-visit-block-core.h" 39 #include "crypto/block.h" 40 #include "migration/blocker.h" 41 #include "crypto.h" 42 43 /**************************************************************/ 44 /* QEMU COW block driver with compression and encryption support */ 45 46 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 47 #define QCOW_VERSION 1 48 49 #define QCOW_CRYPT_NONE 0 50 #define QCOW_CRYPT_AES 1 51 52 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 53 54 typedef struct QCowHeader { 55 uint32_t magic; 56 uint32_t version; 57 uint64_t backing_file_offset; 58 uint32_t backing_file_size; 59 uint32_t mtime; 60 uint64_t size; /* in bytes */ 61 uint8_t cluster_bits; 62 uint8_t l2_bits; 63 uint16_t padding; 64 uint32_t crypt_method; 65 uint64_t l1_table_offset; 66 } QEMU_PACKED QCowHeader; 67 68 #define L2_CACHE_SIZE 16 69 70 typedef struct BDRVQcowState { 71 int cluster_bits; 72 int cluster_size; 73 int cluster_sectors; 74 int l2_bits; 75 int l2_size; 76 unsigned int l1_size; 77 uint64_t cluster_offset_mask; 78 uint64_t l1_table_offset; 79 uint64_t *l1_table; 80 uint64_t *l2_cache; 81 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 82 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 83 uint8_t *cluster_cache; 84 uint8_t *cluster_data; 85 uint64_t cluster_cache_offset; 86 QCryptoBlock *crypto; /* Disk encryption format driver */ 87 uint32_t crypt_method_header; 88 CoMutex lock; 89 Error *migration_blocker; 90 } BDRVQcowState; 91 92 static QemuOptsList qcow_create_opts; 93 94 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 95 96 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 97 { 98 const QCowHeader *cow_header = (const void *)buf; 99 100 if (buf_size >= sizeof(QCowHeader) && 101 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 102 be32_to_cpu(cow_header->version) == QCOW_VERSION) 103 return 100; 104 else 105 return 0; 106 } 107 108 static QemuOptsList qcow_runtime_opts = { 109 .name = "qcow", 110 .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head), 111 .desc = { 112 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 113 { /* end of list */ } 114 }, 115 }; 116 117 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 118 Error **errp) 119 { 120 BDRVQcowState *s = bs->opaque; 121 unsigned int len, i, shift; 122 int ret; 123 QCowHeader header; 124 Error *local_err = NULL; 125 QCryptoBlockOpenOptions *crypto_opts = NULL; 126 unsigned int cflags = 0; 127 QDict *encryptopts = NULL; 128 const char *encryptfmt; 129 130 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 131 encryptfmt = qdict_get_try_str(encryptopts, "format"); 132 133 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 134 false, errp); 135 if (!bs->file) { 136 ret = -EINVAL; 137 goto fail; 138 } 139 140 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 141 if (ret < 0) { 142 goto fail; 143 } 144 be32_to_cpus(&header.magic); 145 be32_to_cpus(&header.version); 146 be64_to_cpus(&header.backing_file_offset); 147 be32_to_cpus(&header.backing_file_size); 148 be32_to_cpus(&header.mtime); 149 be64_to_cpus(&header.size); 150 be32_to_cpus(&header.crypt_method); 151 be64_to_cpus(&header.l1_table_offset); 152 153 if (header.magic != QCOW_MAGIC) { 154 error_setg(errp, "Image not in qcow format"); 155 ret = -EINVAL; 156 goto fail; 157 } 158 if (header.version != QCOW_VERSION) { 159 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 160 ret = -ENOTSUP; 161 goto fail; 162 } 163 164 if (header.size <= 1) { 165 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 166 ret = -EINVAL; 167 goto fail; 168 } 169 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 170 error_setg(errp, "Cluster size must be between 512 and 64k"); 171 ret = -EINVAL; 172 goto fail; 173 } 174 175 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 176 * so bytes = num_entries << 3. */ 177 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 178 error_setg(errp, "L2 table size must be between 512 and 64k"); 179 ret = -EINVAL; 180 goto fail; 181 } 182 183 s->crypt_method_header = header.crypt_method; 184 if (s->crypt_method_header) { 185 if (bdrv_uses_whitelist() && 186 s->crypt_method_header == QCOW_CRYPT_AES) { 187 error_setg(errp, 188 "Use of AES-CBC encrypted qcow images is no longer " 189 "supported in system emulators"); 190 error_append_hint(errp, 191 "You can use 'qemu-img convert' to convert your " 192 "image to an alternative supported format, such " 193 "as unencrypted qcow, or raw with the LUKS " 194 "format instead.\n"); 195 ret = -ENOSYS; 196 goto fail; 197 } 198 if (s->crypt_method_header == QCOW_CRYPT_AES) { 199 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 200 error_setg(errp, 201 "Header reported 'aes' encryption format but " 202 "options specify '%s'", encryptfmt); 203 ret = -EINVAL; 204 goto fail; 205 } 206 qdict_del(encryptopts, "format"); 207 crypto_opts = block_crypto_open_opts_init( 208 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); 209 if (!crypto_opts) { 210 ret = -EINVAL; 211 goto fail; 212 } 213 214 if (flags & BDRV_O_NO_IO) { 215 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 216 } 217 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 218 NULL, NULL, cflags, errp); 219 if (!s->crypto) { 220 ret = -EINVAL; 221 goto fail; 222 } 223 } else { 224 error_setg(errp, "invalid encryption method in qcow header"); 225 ret = -EINVAL; 226 goto fail; 227 } 228 bs->encrypted = true; 229 } else { 230 if (encryptfmt) { 231 error_setg(errp, "No encryption in image header, but options " 232 "specified format '%s'", encryptfmt); 233 ret = -EINVAL; 234 goto fail; 235 } 236 } 237 s->cluster_bits = header.cluster_bits; 238 s->cluster_size = 1 << s->cluster_bits; 239 s->cluster_sectors = 1 << (s->cluster_bits - 9); 240 s->l2_bits = header.l2_bits; 241 s->l2_size = 1 << s->l2_bits; 242 bs->total_sectors = header.size / 512; 243 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 244 245 /* read the level 1 table */ 246 shift = s->cluster_bits + s->l2_bits; 247 if (header.size > UINT64_MAX - (1LL << shift)) { 248 error_setg(errp, "Image too large"); 249 ret = -EINVAL; 250 goto fail; 251 } else { 252 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 253 if (l1_size > INT_MAX / sizeof(uint64_t)) { 254 error_setg(errp, "Image too large"); 255 ret = -EINVAL; 256 goto fail; 257 } 258 s->l1_size = l1_size; 259 } 260 261 s->l1_table_offset = header.l1_table_offset; 262 s->l1_table = g_try_new(uint64_t, s->l1_size); 263 if (s->l1_table == NULL) { 264 error_setg(errp, "Could not allocate memory for L1 table"); 265 ret = -ENOMEM; 266 goto fail; 267 } 268 269 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 270 s->l1_size * sizeof(uint64_t)); 271 if (ret < 0) { 272 goto fail; 273 } 274 275 for(i = 0;i < s->l1_size; i++) { 276 be64_to_cpus(&s->l1_table[i]); 277 } 278 279 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 280 s->l2_cache = 281 qemu_try_blockalign(bs->file->bs, 282 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 283 if (s->l2_cache == NULL) { 284 error_setg(errp, "Could not allocate L2 table cache"); 285 ret = -ENOMEM; 286 goto fail; 287 } 288 s->cluster_cache = g_malloc(s->cluster_size); 289 s->cluster_data = g_malloc(s->cluster_size); 290 s->cluster_cache_offset = -1; 291 292 /* read the backing file name */ 293 if (header.backing_file_offset != 0) { 294 len = header.backing_file_size; 295 if (len > 1023 || len >= sizeof(bs->backing_file)) { 296 error_setg(errp, "Backing file name too long"); 297 ret = -EINVAL; 298 goto fail; 299 } 300 ret = bdrv_pread(bs->file, header.backing_file_offset, 301 bs->backing_file, len); 302 if (ret < 0) { 303 goto fail; 304 } 305 bs->backing_file[len] = '\0'; 306 } 307 308 /* Disable migration when qcow images are used */ 309 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 310 "does not support live migration", 311 bdrv_get_device_or_node_name(bs)); 312 ret = migrate_add_blocker(s->migration_blocker, &local_err); 313 if (local_err) { 314 error_propagate(errp, local_err); 315 error_free(s->migration_blocker); 316 goto fail; 317 } 318 319 qobject_unref(encryptopts); 320 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 321 qemu_co_mutex_init(&s->lock); 322 return 0; 323 324 fail: 325 g_free(s->l1_table); 326 qemu_vfree(s->l2_cache); 327 g_free(s->cluster_cache); 328 g_free(s->cluster_data); 329 qcrypto_block_free(s->crypto); 330 qobject_unref(encryptopts); 331 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 332 return ret; 333 } 334 335 336 /* We have nothing to do for QCOW reopen, stubs just return 337 * success */ 338 static int qcow_reopen_prepare(BDRVReopenState *state, 339 BlockReopenQueue *queue, Error **errp) 340 { 341 return 0; 342 } 343 344 345 /* 'allocate' is: 346 * 347 * 0 to not allocate. 348 * 349 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 350 * 'n_end') 351 * 352 * 2 to allocate a compressed cluster of size 353 * 'compressed_size'. 'compressed_size' must be > 0 and < 354 * cluster_size 355 * 356 * return 0 if not allocated, 1 if *result is assigned, and negative 357 * errno on failure. 358 */ 359 static int get_cluster_offset(BlockDriverState *bs, 360 uint64_t offset, int allocate, 361 int compressed_size, 362 int n_start, int n_end, uint64_t *result) 363 { 364 BDRVQcowState *s = bs->opaque; 365 int min_index, i, j, l1_index, l2_index, ret; 366 int64_t l2_offset; 367 uint64_t *l2_table, cluster_offset, tmp; 368 uint32_t min_count; 369 int new_l2_table; 370 371 *result = 0; 372 l1_index = offset >> (s->l2_bits + s->cluster_bits); 373 l2_offset = s->l1_table[l1_index]; 374 new_l2_table = 0; 375 if (!l2_offset) { 376 if (!allocate) 377 return 0; 378 /* allocate a new l2 entry */ 379 l2_offset = bdrv_getlength(bs->file->bs); 380 if (l2_offset < 0) { 381 return l2_offset; 382 } 383 /* round to cluster size */ 384 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 385 /* update the L1 entry */ 386 s->l1_table[l1_index] = l2_offset; 387 tmp = cpu_to_be64(l2_offset); 388 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 389 ret = bdrv_pwrite_sync(bs->file, 390 s->l1_table_offset + l1_index * sizeof(tmp), 391 &tmp, sizeof(tmp)); 392 if (ret < 0) { 393 return ret; 394 } 395 new_l2_table = 1; 396 } 397 for(i = 0; i < L2_CACHE_SIZE; i++) { 398 if (l2_offset == s->l2_cache_offsets[i]) { 399 /* increment the hit count */ 400 if (++s->l2_cache_counts[i] == 0xffffffff) { 401 for(j = 0; j < L2_CACHE_SIZE; j++) { 402 s->l2_cache_counts[j] >>= 1; 403 } 404 } 405 l2_table = s->l2_cache + (i << s->l2_bits); 406 goto found; 407 } 408 } 409 /* not found: load a new entry in the least used one */ 410 min_index = 0; 411 min_count = 0xffffffff; 412 for(i = 0; i < L2_CACHE_SIZE; i++) { 413 if (s->l2_cache_counts[i] < min_count) { 414 min_count = s->l2_cache_counts[i]; 415 min_index = i; 416 } 417 } 418 l2_table = s->l2_cache + (min_index << s->l2_bits); 419 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); 420 if (new_l2_table) { 421 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 422 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 423 s->l2_size * sizeof(uint64_t)); 424 if (ret < 0) { 425 return ret; 426 } 427 } else { 428 ret = bdrv_pread(bs->file, l2_offset, l2_table, 429 s->l2_size * sizeof(uint64_t)); 430 if (ret < 0) { 431 return ret; 432 } 433 } 434 s->l2_cache_offsets[min_index] = l2_offset; 435 s->l2_cache_counts[min_index] = 1; 436 found: 437 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 438 cluster_offset = be64_to_cpu(l2_table[l2_index]); 439 if (!cluster_offset || 440 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 441 if (!allocate) 442 return 0; 443 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 444 /* allocate a new cluster */ 445 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 446 (n_end - n_start) < s->cluster_sectors) { 447 /* if the cluster is already compressed, we must 448 decompress it in the case it is not completely 449 overwritten */ 450 if (decompress_cluster(bs, cluster_offset) < 0) { 451 return -EIO; 452 } 453 cluster_offset = bdrv_getlength(bs->file->bs); 454 if ((int64_t) cluster_offset < 0) { 455 return cluster_offset; 456 } 457 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 458 /* write the cluster content */ 459 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 460 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 461 s->cluster_size); 462 if (ret < 0) { 463 return ret; 464 } 465 } else { 466 cluster_offset = bdrv_getlength(bs->file->bs); 467 if ((int64_t) cluster_offset < 0) { 468 return cluster_offset; 469 } 470 if (allocate == 1) { 471 /* round to cluster size */ 472 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 473 if (cluster_offset + s->cluster_size > INT64_MAX) { 474 return -E2BIG; 475 } 476 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 477 PREALLOC_MODE_OFF, NULL); 478 if (ret < 0) { 479 return ret; 480 } 481 /* if encrypted, we must initialize the cluster 482 content which won't be written */ 483 if (bs->encrypted && 484 (n_end - n_start) < s->cluster_sectors) { 485 uint64_t start_sect; 486 assert(s->crypto); 487 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 488 for(i = 0; i < s->cluster_sectors; i++) { 489 if (i < n_start || i >= n_end) { 490 memset(s->cluster_data, 0x00, 512); 491 if (qcrypto_block_encrypt(s->crypto, 492 (start_sect + i) * 493 BDRV_SECTOR_SIZE, 494 s->cluster_data, 495 BDRV_SECTOR_SIZE, 496 NULL) < 0) { 497 return -EIO; 498 } 499 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 500 ret = bdrv_pwrite(bs->file, 501 cluster_offset + i * 512, 502 s->cluster_data, 512); 503 if (ret < 0) { 504 return ret; 505 } 506 } 507 } 508 } 509 } else if (allocate == 2) { 510 cluster_offset |= QCOW_OFLAG_COMPRESSED | 511 (uint64_t)compressed_size << (63 - s->cluster_bits); 512 } 513 } 514 /* update L2 table */ 515 tmp = cpu_to_be64(cluster_offset); 516 l2_table[l2_index] = tmp; 517 if (allocate == 2) { 518 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); 519 } else { 520 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); 521 } 522 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 523 &tmp, sizeof(tmp)); 524 if (ret < 0) { 525 return ret; 526 } 527 } 528 *result = cluster_offset; 529 return 1; 530 } 531 532 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs, 533 bool want_zero, 534 int64_t offset, int64_t bytes, 535 int64_t *pnum, int64_t *map, 536 BlockDriverState **file) 537 { 538 BDRVQcowState *s = bs->opaque; 539 int index_in_cluster, ret; 540 int64_t n; 541 uint64_t cluster_offset; 542 543 qemu_co_mutex_lock(&s->lock); 544 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 545 qemu_co_mutex_unlock(&s->lock); 546 if (ret < 0) { 547 return ret; 548 } 549 index_in_cluster = offset & (s->cluster_size - 1); 550 n = s->cluster_size - index_in_cluster; 551 if (n > bytes) { 552 n = bytes; 553 } 554 *pnum = n; 555 if (!cluster_offset) { 556 return 0; 557 } 558 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 559 return BDRV_BLOCK_DATA; 560 } 561 *map = cluster_offset | index_in_cluster; 562 *file = bs->file->bs; 563 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 564 } 565 566 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 567 const uint8_t *buf, int buf_size) 568 { 569 z_stream strm1, *strm = &strm1; 570 int ret, out_len; 571 572 memset(strm, 0, sizeof(*strm)); 573 574 strm->next_in = (uint8_t *)buf; 575 strm->avail_in = buf_size; 576 strm->next_out = out_buf; 577 strm->avail_out = out_buf_size; 578 579 ret = inflateInit2(strm, -12); 580 if (ret != Z_OK) 581 return -1; 582 ret = inflate(strm, Z_FINISH); 583 out_len = strm->next_out - out_buf; 584 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 585 out_len != out_buf_size) { 586 inflateEnd(strm); 587 return -1; 588 } 589 inflateEnd(strm); 590 return 0; 591 } 592 593 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 594 { 595 BDRVQcowState *s = bs->opaque; 596 int ret, csize; 597 uint64_t coffset; 598 599 coffset = cluster_offset & s->cluster_offset_mask; 600 if (s->cluster_cache_offset != coffset) { 601 csize = cluster_offset >> (63 - s->cluster_bits); 602 csize &= (s->cluster_size - 1); 603 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 604 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 605 if (ret != csize) 606 return -1; 607 if (decompress_buffer(s->cluster_cache, s->cluster_size, 608 s->cluster_data, csize) < 0) { 609 return -1; 610 } 611 s->cluster_cache_offset = coffset; 612 } 613 return 0; 614 } 615 616 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 617 int nb_sectors, QEMUIOVector *qiov) 618 { 619 BDRVQcowState *s = bs->opaque; 620 int index_in_cluster; 621 int ret = 0, n; 622 uint64_t cluster_offset; 623 struct iovec hd_iov; 624 QEMUIOVector hd_qiov; 625 uint8_t *buf; 626 void *orig_buf; 627 628 if (qiov->niov > 1) { 629 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 630 if (buf == NULL) { 631 return -ENOMEM; 632 } 633 } else { 634 orig_buf = NULL; 635 buf = (uint8_t *)qiov->iov->iov_base; 636 } 637 638 qemu_co_mutex_lock(&s->lock); 639 640 while (nb_sectors != 0) { 641 /* prepare next request */ 642 ret = get_cluster_offset(bs, sector_num << 9, 643 0, 0, 0, 0, &cluster_offset); 644 if (ret < 0) { 645 break; 646 } 647 index_in_cluster = sector_num & (s->cluster_sectors - 1); 648 n = s->cluster_sectors - index_in_cluster; 649 if (n > nb_sectors) { 650 n = nb_sectors; 651 } 652 653 if (!cluster_offset) { 654 if (bs->backing) { 655 /* read from the base image */ 656 hd_iov.iov_base = (void *)buf; 657 hd_iov.iov_len = n * 512; 658 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 659 qemu_co_mutex_unlock(&s->lock); 660 /* qcow2 emits this on bs->file instead of bs->backing */ 661 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 662 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 663 qemu_co_mutex_lock(&s->lock); 664 if (ret < 0) { 665 break; 666 } 667 } else { 668 /* Note: in this case, no need to wait */ 669 memset(buf, 0, 512 * n); 670 } 671 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 672 /* add AIO support for compressed blocks ? */ 673 if (decompress_cluster(bs, cluster_offset) < 0) { 674 ret = -EIO; 675 break; 676 } 677 memcpy(buf, 678 s->cluster_cache + index_in_cluster * 512, 512 * n); 679 } else { 680 if ((cluster_offset & 511) != 0) { 681 ret = -EIO; 682 break; 683 } 684 hd_iov.iov_base = (void *)buf; 685 hd_iov.iov_len = n * 512; 686 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 687 qemu_co_mutex_unlock(&s->lock); 688 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 689 ret = bdrv_co_readv(bs->file, 690 (cluster_offset >> 9) + index_in_cluster, 691 n, &hd_qiov); 692 qemu_co_mutex_lock(&s->lock); 693 if (ret < 0) { 694 break; 695 } 696 if (bs->encrypted) { 697 assert(s->crypto); 698 if (qcrypto_block_decrypt(s->crypto, 699 sector_num * BDRV_SECTOR_SIZE, buf, 700 n * BDRV_SECTOR_SIZE, NULL) < 0) { 701 ret = -EIO; 702 break; 703 } 704 } 705 } 706 ret = 0; 707 708 nb_sectors -= n; 709 sector_num += n; 710 buf += n * 512; 711 } 712 713 qemu_co_mutex_unlock(&s->lock); 714 715 if (qiov->niov > 1) { 716 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 717 qemu_vfree(orig_buf); 718 } 719 720 return ret; 721 } 722 723 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 724 int nb_sectors, QEMUIOVector *qiov, 725 int flags) 726 { 727 BDRVQcowState *s = bs->opaque; 728 int index_in_cluster; 729 uint64_t cluster_offset; 730 int ret = 0, n; 731 struct iovec hd_iov; 732 QEMUIOVector hd_qiov; 733 uint8_t *buf; 734 void *orig_buf; 735 736 assert(!flags); 737 s->cluster_cache_offset = -1; /* disable compressed cache */ 738 739 /* We must always copy the iov when encrypting, so we 740 * don't modify the original data buffer during encryption */ 741 if (bs->encrypted || qiov->niov > 1) { 742 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 743 if (buf == NULL) { 744 return -ENOMEM; 745 } 746 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 747 } else { 748 orig_buf = NULL; 749 buf = (uint8_t *)qiov->iov->iov_base; 750 } 751 752 qemu_co_mutex_lock(&s->lock); 753 754 while (nb_sectors != 0) { 755 756 index_in_cluster = sector_num & (s->cluster_sectors - 1); 757 n = s->cluster_sectors - index_in_cluster; 758 if (n > nb_sectors) { 759 n = nb_sectors; 760 } 761 ret = get_cluster_offset(bs, sector_num << 9, 1, 0, 762 index_in_cluster, 763 index_in_cluster + n, &cluster_offset); 764 if (ret < 0) { 765 break; 766 } 767 if (!cluster_offset || (cluster_offset & 511) != 0) { 768 ret = -EIO; 769 break; 770 } 771 if (bs->encrypted) { 772 assert(s->crypto); 773 if (qcrypto_block_encrypt(s->crypto, sector_num * BDRV_SECTOR_SIZE, 774 buf, n * BDRV_SECTOR_SIZE, NULL) < 0) { 775 ret = -EIO; 776 break; 777 } 778 } 779 780 hd_iov.iov_base = (void *)buf; 781 hd_iov.iov_len = n * 512; 782 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 783 qemu_co_mutex_unlock(&s->lock); 784 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 785 ret = bdrv_co_writev(bs->file, 786 (cluster_offset >> 9) + index_in_cluster, 787 n, &hd_qiov); 788 qemu_co_mutex_lock(&s->lock); 789 if (ret < 0) { 790 break; 791 } 792 ret = 0; 793 794 nb_sectors -= n; 795 sector_num += n; 796 buf += n * 512; 797 } 798 qemu_co_mutex_unlock(&s->lock); 799 800 qemu_vfree(orig_buf); 801 802 return ret; 803 } 804 805 static void qcow_close(BlockDriverState *bs) 806 { 807 BDRVQcowState *s = bs->opaque; 808 809 qcrypto_block_free(s->crypto); 810 s->crypto = NULL; 811 g_free(s->l1_table); 812 qemu_vfree(s->l2_cache); 813 g_free(s->cluster_cache); 814 g_free(s->cluster_data); 815 816 migrate_del_blocker(s->migration_blocker); 817 error_free(s->migration_blocker); 818 } 819 820 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts, 821 Error **errp) 822 { 823 BlockdevCreateOptionsQcow *qcow_opts; 824 int header_size, backing_filename_len, l1_size, shift, i; 825 QCowHeader header; 826 uint8_t *tmp; 827 int64_t total_size = 0; 828 int ret; 829 BlockDriverState *bs; 830 BlockBackend *qcow_blk; 831 QCryptoBlock *crypto = NULL; 832 833 assert(opts->driver == BLOCKDEV_DRIVER_QCOW); 834 qcow_opts = &opts->u.qcow; 835 836 /* Sanity checks */ 837 total_size = qcow_opts->size; 838 if (total_size == 0) { 839 error_setg(errp, "Image size is too small, cannot be zero length"); 840 return -EINVAL; 841 } 842 843 if (qcow_opts->has_encrypt && 844 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) 845 { 846 error_setg(errp, "Unsupported encryption format"); 847 return -EINVAL; 848 } 849 850 /* Create BlockBackend to write to the image */ 851 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp); 852 if (bs == NULL) { 853 return -EIO; 854 } 855 856 qcow_blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 857 ret = blk_insert_bs(qcow_blk, bs, errp); 858 if (ret < 0) { 859 goto exit; 860 } 861 blk_set_allow_write_beyond_eof(qcow_blk, true); 862 863 /* Create image format */ 864 ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp); 865 if (ret < 0) { 866 goto exit; 867 } 868 869 memset(&header, 0, sizeof(header)); 870 header.magic = cpu_to_be32(QCOW_MAGIC); 871 header.version = cpu_to_be32(QCOW_VERSION); 872 header.size = cpu_to_be64(total_size); 873 header_size = sizeof(header); 874 backing_filename_len = 0; 875 if (qcow_opts->has_backing_file) { 876 if (strcmp(qcow_opts->backing_file, "fat:")) { 877 header.backing_file_offset = cpu_to_be64(header_size); 878 backing_filename_len = strlen(qcow_opts->backing_file); 879 header.backing_file_size = cpu_to_be32(backing_filename_len); 880 header_size += backing_filename_len; 881 } else { 882 /* special backing file for vvfat */ 883 qcow_opts->has_backing_file = false; 884 } 885 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 886 unmodified sectors */ 887 header.l2_bits = 12; /* 32 KB L2 tables */ 888 } else { 889 header.cluster_bits = 12; /* 4 KB clusters */ 890 header.l2_bits = 9; /* 4 KB L2 tables */ 891 } 892 header_size = (header_size + 7) & ~7; 893 shift = header.cluster_bits + header.l2_bits; 894 l1_size = (total_size + (1LL << shift) - 1) >> shift; 895 896 header.l1_table_offset = cpu_to_be64(header_size); 897 898 if (qcow_opts->has_encrypt) { 899 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 900 901 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.", 902 NULL, NULL, NULL, errp); 903 if (!crypto) { 904 ret = -EINVAL; 905 goto exit; 906 } 907 } else { 908 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 909 } 910 911 /* write all the data */ 912 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 913 if (ret != sizeof(header)) { 914 goto exit; 915 } 916 917 if (qcow_opts->has_backing_file) { 918 ret = blk_pwrite(qcow_blk, sizeof(header), 919 qcow_opts->backing_file, backing_filename_len, 0); 920 if (ret != backing_filename_len) { 921 goto exit; 922 } 923 } 924 925 tmp = g_malloc0(BDRV_SECTOR_SIZE); 926 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 927 i++) { 928 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 929 tmp, BDRV_SECTOR_SIZE, 0); 930 if (ret != BDRV_SECTOR_SIZE) { 931 g_free(tmp); 932 goto exit; 933 } 934 } 935 936 g_free(tmp); 937 ret = 0; 938 exit: 939 blk_unref(qcow_blk); 940 qcrypto_block_free(crypto); 941 return ret; 942 } 943 944 static int coroutine_fn qcow_co_create_opts(const char *filename, 945 QemuOpts *opts, Error **errp) 946 { 947 BlockdevCreateOptions *create_options = NULL; 948 BlockDriverState *bs = NULL; 949 QDict *qdict; 950 Visitor *v; 951 const char *val; 952 Error *local_err = NULL; 953 int ret; 954 955 static const QDictRenames opt_renames[] = { 956 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 957 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 958 { NULL, NULL }, 959 }; 960 961 /* Parse options and convert legacy syntax */ 962 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); 963 964 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 965 if (val && !strcmp(val, "on")) { 966 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 967 } else if (val && !strcmp(val, "off")) { 968 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 969 } 970 971 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 972 if (val && !strcmp(val, "aes")) { 973 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 974 } 975 976 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 977 ret = -EINVAL; 978 goto fail; 979 } 980 981 /* Create and open the file (protocol layer) */ 982 ret = bdrv_create_file(filename, opts, &local_err); 983 if (ret < 0) { 984 error_propagate(errp, local_err); 985 goto fail; 986 } 987 988 bs = bdrv_open(filename, NULL, NULL, 989 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 990 if (bs == NULL) { 991 ret = -EIO; 992 goto fail; 993 } 994 995 /* Now get the QAPI type BlockdevCreateOptions */ 996 qdict_put_str(qdict, "driver", "qcow"); 997 qdict_put_str(qdict, "file", bs->node_name); 998 999 v = qobject_input_visitor_new_flat_confused(qdict, errp); 1000 if (!v) { 1001 ret = -EINVAL; 1002 goto fail; 1003 } 1004 1005 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 1006 visit_free(v); 1007 1008 if (local_err) { 1009 error_propagate(errp, local_err); 1010 ret = -EINVAL; 1011 goto fail; 1012 } 1013 1014 /* Silently round up size */ 1015 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); 1016 create_options->u.qcow.size = 1017 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); 1018 1019 /* Create the qcow image (format layer) */ 1020 ret = qcow_co_create(create_options, errp); 1021 if (ret < 0) { 1022 goto fail; 1023 } 1024 1025 ret = 0; 1026 fail: 1027 qobject_unref(qdict); 1028 bdrv_unref(bs); 1029 qapi_free_BlockdevCreateOptions(create_options); 1030 return ret; 1031 } 1032 1033 static int qcow_make_empty(BlockDriverState *bs) 1034 { 1035 BDRVQcowState *s = bs->opaque; 1036 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 1037 int ret; 1038 1039 memset(s->l1_table, 0, l1_length); 1040 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 1041 l1_length) < 0) 1042 return -1; 1043 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, 1044 PREALLOC_MODE_OFF, NULL); 1045 if (ret < 0) 1046 return ret; 1047 1048 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 1049 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 1050 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 1051 1052 return 0; 1053 } 1054 1055 /* XXX: put compressed sectors first, then all the cluster aligned 1056 tables to avoid losing bytes in alignment */ 1057 static coroutine_fn int 1058 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 1059 uint64_t bytes, QEMUIOVector *qiov) 1060 { 1061 BDRVQcowState *s = bs->opaque; 1062 QEMUIOVector hd_qiov; 1063 struct iovec iov; 1064 z_stream strm; 1065 int ret, out_len; 1066 uint8_t *buf, *out_buf; 1067 uint64_t cluster_offset; 1068 1069 buf = qemu_blockalign(bs, s->cluster_size); 1070 if (bytes != s->cluster_size) { 1071 if (bytes > s->cluster_size || 1072 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 1073 { 1074 qemu_vfree(buf); 1075 return -EINVAL; 1076 } 1077 /* Zero-pad last write if image size is not cluster aligned */ 1078 memset(buf + bytes, 0, s->cluster_size - bytes); 1079 } 1080 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 1081 1082 out_buf = g_malloc(s->cluster_size); 1083 1084 /* best compression, small window, no zlib header */ 1085 memset(&strm, 0, sizeof(strm)); 1086 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 1087 Z_DEFLATED, -12, 1088 9, Z_DEFAULT_STRATEGY); 1089 if (ret != 0) { 1090 ret = -EINVAL; 1091 goto fail; 1092 } 1093 1094 strm.avail_in = s->cluster_size; 1095 strm.next_in = (uint8_t *)buf; 1096 strm.avail_out = s->cluster_size; 1097 strm.next_out = out_buf; 1098 1099 ret = deflate(&strm, Z_FINISH); 1100 if (ret != Z_STREAM_END && ret != Z_OK) { 1101 deflateEnd(&strm); 1102 ret = -EINVAL; 1103 goto fail; 1104 } 1105 out_len = strm.next_out - out_buf; 1106 1107 deflateEnd(&strm); 1108 1109 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1110 /* could not compress: write normal cluster */ 1111 ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS, 1112 bytes >> BDRV_SECTOR_BITS, qiov, 0); 1113 if (ret < 0) { 1114 goto fail; 1115 } 1116 goto success; 1117 } 1118 qemu_co_mutex_lock(&s->lock); 1119 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); 1120 qemu_co_mutex_unlock(&s->lock); 1121 if (ret < 0) { 1122 goto fail; 1123 } 1124 if (cluster_offset == 0) { 1125 ret = -EIO; 1126 goto fail; 1127 } 1128 cluster_offset &= s->cluster_offset_mask; 1129 1130 iov = (struct iovec) { 1131 .iov_base = out_buf, 1132 .iov_len = out_len, 1133 }; 1134 qemu_iovec_init_external(&hd_qiov, &iov, 1); 1135 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 1136 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1137 if (ret < 0) { 1138 goto fail; 1139 } 1140 success: 1141 ret = 0; 1142 fail: 1143 qemu_vfree(buf); 1144 g_free(out_buf); 1145 return ret; 1146 } 1147 1148 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1149 { 1150 BDRVQcowState *s = bs->opaque; 1151 bdi->cluster_size = s->cluster_size; 1152 return 0; 1153 } 1154 1155 static QemuOptsList qcow_create_opts = { 1156 .name = "qcow-create-opts", 1157 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1158 .desc = { 1159 { 1160 .name = BLOCK_OPT_SIZE, 1161 .type = QEMU_OPT_SIZE, 1162 .help = "Virtual disk size" 1163 }, 1164 { 1165 .name = BLOCK_OPT_BACKING_FILE, 1166 .type = QEMU_OPT_STRING, 1167 .help = "File name of a base image" 1168 }, 1169 { 1170 .name = BLOCK_OPT_ENCRYPT, 1171 .type = QEMU_OPT_BOOL, 1172 .help = "Encrypt the image with format 'aes'. (Deprecated " 1173 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1174 }, 1175 { 1176 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1177 .type = QEMU_OPT_STRING, 1178 .help = "Encrypt the image, format choices: 'aes'", 1179 }, 1180 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1181 { /* end of list */ } 1182 } 1183 }; 1184 1185 static BlockDriver bdrv_qcow = { 1186 .format_name = "qcow", 1187 .instance_size = sizeof(BDRVQcowState), 1188 .bdrv_probe = qcow_probe, 1189 .bdrv_open = qcow_open, 1190 .bdrv_close = qcow_close, 1191 .bdrv_child_perm = bdrv_format_default_perms, 1192 .bdrv_reopen_prepare = qcow_reopen_prepare, 1193 .bdrv_co_create = qcow_co_create, 1194 .bdrv_co_create_opts = qcow_co_create_opts, 1195 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1196 .supports_backing = true, 1197 1198 .bdrv_co_readv = qcow_co_readv, 1199 .bdrv_co_writev = qcow_co_writev, 1200 .bdrv_co_block_status = qcow_co_block_status, 1201 1202 .bdrv_make_empty = qcow_make_empty, 1203 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1204 .bdrv_get_info = qcow_get_info, 1205 1206 .create_opts = &qcow_create_opts, 1207 }; 1208 1209 static void bdrv_qcow_init(void) 1210 { 1211 bdrv_register(&bdrv_qcow); 1212 } 1213 1214 block_init(bdrv_qcow_init); 1215