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-common.h" 25 #include "block_int.h" 26 #include "module.h" 27 #include <zlib.h> 28 #include "aes.h" 29 #include "migration.h" 30 31 /**************************************************************/ 32 /* QEMU COW block driver with compression and encryption support */ 33 34 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 35 #define QCOW_VERSION 1 36 37 #define QCOW_CRYPT_NONE 0 38 #define QCOW_CRYPT_AES 1 39 40 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 41 42 typedef struct QCowHeader { 43 uint32_t magic; 44 uint32_t version; 45 uint64_t backing_file_offset; 46 uint32_t backing_file_size; 47 uint32_t mtime; 48 uint64_t size; /* in bytes */ 49 uint8_t cluster_bits; 50 uint8_t l2_bits; 51 uint32_t crypt_method; 52 uint64_t l1_table_offset; 53 } QCowHeader; 54 55 #define L2_CACHE_SIZE 16 56 57 typedef struct BDRVQcowState { 58 int cluster_bits; 59 int cluster_size; 60 int cluster_sectors; 61 int l2_bits; 62 int l2_size; 63 int l1_size; 64 uint64_t cluster_offset_mask; 65 uint64_t l1_table_offset; 66 uint64_t *l1_table; 67 uint64_t *l2_cache; 68 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 69 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 70 uint8_t *cluster_cache; 71 uint8_t *cluster_data; 72 uint64_t cluster_cache_offset; 73 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 74 uint32_t crypt_method_header; 75 AES_KEY aes_encrypt_key; 76 AES_KEY aes_decrypt_key; 77 CoMutex lock; 78 Error *migration_blocker; 79 } BDRVQcowState; 80 81 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 82 83 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 84 { 85 const QCowHeader *cow_header = (const void *)buf; 86 87 if (buf_size >= sizeof(QCowHeader) && 88 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 89 be32_to_cpu(cow_header->version) == QCOW_VERSION) 90 return 100; 91 else 92 return 0; 93 } 94 95 static int qcow_open(BlockDriverState *bs, int flags) 96 { 97 BDRVQcowState *s = bs->opaque; 98 int len, i, shift, ret; 99 QCowHeader header; 100 101 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 102 if (ret < 0) { 103 goto fail; 104 } 105 be32_to_cpus(&header.magic); 106 be32_to_cpus(&header.version); 107 be64_to_cpus(&header.backing_file_offset); 108 be32_to_cpus(&header.backing_file_size); 109 be32_to_cpus(&header.mtime); 110 be64_to_cpus(&header.size); 111 be32_to_cpus(&header.crypt_method); 112 be64_to_cpus(&header.l1_table_offset); 113 114 if (header.magic != QCOW_MAGIC) { 115 ret = -EINVAL; 116 goto fail; 117 } 118 if (header.version != QCOW_VERSION) { 119 char version[64]; 120 snprintf(version, sizeof(version), "QCOW version %d", header.version); 121 qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 122 bs->device_name, "qcow", version); 123 ret = -ENOTSUP; 124 goto fail; 125 } 126 127 if (header.size <= 1 || header.cluster_bits < 9) { 128 ret = -EINVAL; 129 goto fail; 130 } 131 if (header.crypt_method > QCOW_CRYPT_AES) { 132 ret = -EINVAL; 133 goto fail; 134 } 135 s->crypt_method_header = header.crypt_method; 136 if (s->crypt_method_header) { 137 bs->encrypted = 1; 138 } 139 s->cluster_bits = header.cluster_bits; 140 s->cluster_size = 1 << s->cluster_bits; 141 s->cluster_sectors = 1 << (s->cluster_bits - 9); 142 s->l2_bits = header.l2_bits; 143 s->l2_size = 1 << s->l2_bits; 144 bs->total_sectors = header.size / 512; 145 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 146 147 /* read the level 1 table */ 148 shift = s->cluster_bits + s->l2_bits; 149 s->l1_size = (header.size + (1LL << shift) - 1) >> shift; 150 151 s->l1_table_offset = header.l1_table_offset; 152 s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); 153 154 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 155 s->l1_size * sizeof(uint64_t)); 156 if (ret < 0) { 157 goto fail; 158 } 159 160 for(i = 0;i < s->l1_size; i++) { 161 be64_to_cpus(&s->l1_table[i]); 162 } 163 /* alloc L2 cache */ 164 s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 165 s->cluster_cache = g_malloc(s->cluster_size); 166 s->cluster_data = g_malloc(s->cluster_size); 167 s->cluster_cache_offset = -1; 168 169 /* read the backing file name */ 170 if (header.backing_file_offset != 0) { 171 len = header.backing_file_size; 172 if (len > 1023) { 173 len = 1023; 174 } 175 ret = bdrv_pread(bs->file, header.backing_file_offset, 176 bs->backing_file, len); 177 if (ret < 0) { 178 goto fail; 179 } 180 bs->backing_file[len] = '\0'; 181 } 182 183 /* Disable migration when qcow images are used */ 184 error_set(&s->migration_blocker, 185 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 186 "qcow", bs->device_name, "live migration"); 187 migrate_add_blocker(s->migration_blocker); 188 189 qemu_co_mutex_init(&s->lock); 190 return 0; 191 192 fail: 193 g_free(s->l1_table); 194 g_free(s->l2_cache); 195 g_free(s->cluster_cache); 196 g_free(s->cluster_data); 197 return ret; 198 } 199 200 static int qcow_set_key(BlockDriverState *bs, const char *key) 201 { 202 BDRVQcowState *s = bs->opaque; 203 uint8_t keybuf[16]; 204 int len, i; 205 206 memset(keybuf, 0, 16); 207 len = strlen(key); 208 if (len > 16) 209 len = 16; 210 /* XXX: we could compress the chars to 7 bits to increase 211 entropy */ 212 for(i = 0;i < len;i++) { 213 keybuf[i] = key[i]; 214 } 215 s->crypt_method = s->crypt_method_header; 216 217 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 218 return -1; 219 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 220 return -1; 221 return 0; 222 } 223 224 /* The crypt function is compatible with the linux cryptoloop 225 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 226 supported */ 227 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 228 uint8_t *out_buf, const uint8_t *in_buf, 229 int nb_sectors, int enc, 230 const AES_KEY *key) 231 { 232 union { 233 uint64_t ll[2]; 234 uint8_t b[16]; 235 } ivec; 236 int i; 237 238 for(i = 0; i < nb_sectors; i++) { 239 ivec.ll[0] = cpu_to_le64(sector_num); 240 ivec.ll[1] = 0; 241 AES_cbc_encrypt(in_buf, out_buf, 512, key, 242 ivec.b, enc); 243 sector_num++; 244 in_buf += 512; 245 out_buf += 512; 246 } 247 } 248 249 /* 'allocate' is: 250 * 251 * 0 to not allocate. 252 * 253 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 254 * 'n_end') 255 * 256 * 2 to allocate a compressed cluster of size 257 * 'compressed_size'. 'compressed_size' must be > 0 and < 258 * cluster_size 259 * 260 * return 0 if not allocated. 261 */ 262 static uint64_t get_cluster_offset(BlockDriverState *bs, 263 uint64_t offset, int allocate, 264 int compressed_size, 265 int n_start, int n_end) 266 { 267 BDRVQcowState *s = bs->opaque; 268 int min_index, i, j, l1_index, l2_index; 269 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 270 uint32_t min_count; 271 int new_l2_table; 272 273 l1_index = offset >> (s->l2_bits + s->cluster_bits); 274 l2_offset = s->l1_table[l1_index]; 275 new_l2_table = 0; 276 if (!l2_offset) { 277 if (!allocate) 278 return 0; 279 /* allocate a new l2 entry */ 280 l2_offset = bdrv_getlength(bs->file); 281 /* round to cluster size */ 282 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 283 /* update the L1 entry */ 284 s->l1_table[l1_index] = l2_offset; 285 tmp = cpu_to_be64(l2_offset); 286 if (bdrv_pwrite_sync(bs->file, 287 s->l1_table_offset + l1_index * sizeof(tmp), 288 &tmp, sizeof(tmp)) < 0) 289 return 0; 290 new_l2_table = 1; 291 } 292 for(i = 0; i < L2_CACHE_SIZE; i++) { 293 if (l2_offset == s->l2_cache_offsets[i]) { 294 /* increment the hit count */ 295 if (++s->l2_cache_counts[i] == 0xffffffff) { 296 for(j = 0; j < L2_CACHE_SIZE; j++) { 297 s->l2_cache_counts[j] >>= 1; 298 } 299 } 300 l2_table = s->l2_cache + (i << s->l2_bits); 301 goto found; 302 } 303 } 304 /* not found: load a new entry in the least used one */ 305 min_index = 0; 306 min_count = 0xffffffff; 307 for(i = 0; i < L2_CACHE_SIZE; i++) { 308 if (s->l2_cache_counts[i] < min_count) { 309 min_count = s->l2_cache_counts[i]; 310 min_index = i; 311 } 312 } 313 l2_table = s->l2_cache + (min_index << s->l2_bits); 314 if (new_l2_table) { 315 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 316 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 317 s->l2_size * sizeof(uint64_t)) < 0) 318 return 0; 319 } else { 320 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 321 s->l2_size * sizeof(uint64_t)) 322 return 0; 323 } 324 s->l2_cache_offsets[min_index] = l2_offset; 325 s->l2_cache_counts[min_index] = 1; 326 found: 327 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 328 cluster_offset = be64_to_cpu(l2_table[l2_index]); 329 if (!cluster_offset || 330 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 331 if (!allocate) 332 return 0; 333 /* allocate a new cluster */ 334 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 335 (n_end - n_start) < s->cluster_sectors) { 336 /* if the cluster is already compressed, we must 337 decompress it in the case it is not completely 338 overwritten */ 339 if (decompress_cluster(bs, cluster_offset) < 0) 340 return 0; 341 cluster_offset = bdrv_getlength(bs->file); 342 cluster_offset = (cluster_offset + s->cluster_size - 1) & 343 ~(s->cluster_size - 1); 344 /* write the cluster content */ 345 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 346 s->cluster_size) 347 return -1; 348 } else { 349 cluster_offset = bdrv_getlength(bs->file); 350 if (allocate == 1) { 351 /* round to cluster size */ 352 cluster_offset = (cluster_offset + s->cluster_size - 1) & 353 ~(s->cluster_size - 1); 354 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 355 /* if encrypted, we must initialize the cluster 356 content which won't be written */ 357 if (s->crypt_method && 358 (n_end - n_start) < s->cluster_sectors) { 359 uint64_t start_sect; 360 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 361 memset(s->cluster_data + 512, 0x00, 512); 362 for(i = 0; i < s->cluster_sectors; i++) { 363 if (i < n_start || i >= n_end) { 364 encrypt_sectors(s, start_sect + i, 365 s->cluster_data, 366 s->cluster_data + 512, 1, 1, 367 &s->aes_encrypt_key); 368 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 369 s->cluster_data, 512) != 512) 370 return -1; 371 } 372 } 373 } 374 } else if (allocate == 2) { 375 cluster_offset |= QCOW_OFLAG_COMPRESSED | 376 (uint64_t)compressed_size << (63 - s->cluster_bits); 377 } 378 } 379 /* update L2 table */ 380 tmp = cpu_to_be64(cluster_offset); 381 l2_table[l2_index] = tmp; 382 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 383 &tmp, sizeof(tmp)) < 0) 384 return 0; 385 } 386 return cluster_offset; 387 } 388 389 static int coroutine_fn qcow_co_is_allocated(BlockDriverState *bs, 390 int64_t sector_num, int nb_sectors, int *pnum) 391 { 392 BDRVQcowState *s = bs->opaque; 393 int index_in_cluster, n; 394 uint64_t cluster_offset; 395 396 qemu_co_mutex_lock(&s->lock); 397 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 398 qemu_co_mutex_unlock(&s->lock); 399 index_in_cluster = sector_num & (s->cluster_sectors - 1); 400 n = s->cluster_sectors - index_in_cluster; 401 if (n > nb_sectors) 402 n = nb_sectors; 403 *pnum = n; 404 return (cluster_offset != 0); 405 } 406 407 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 408 const uint8_t *buf, int buf_size) 409 { 410 z_stream strm1, *strm = &strm1; 411 int ret, out_len; 412 413 memset(strm, 0, sizeof(*strm)); 414 415 strm->next_in = (uint8_t *)buf; 416 strm->avail_in = buf_size; 417 strm->next_out = out_buf; 418 strm->avail_out = out_buf_size; 419 420 ret = inflateInit2(strm, -12); 421 if (ret != Z_OK) 422 return -1; 423 ret = inflate(strm, Z_FINISH); 424 out_len = strm->next_out - out_buf; 425 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 426 out_len != out_buf_size) { 427 inflateEnd(strm); 428 return -1; 429 } 430 inflateEnd(strm); 431 return 0; 432 } 433 434 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 435 { 436 BDRVQcowState *s = bs->opaque; 437 int ret, csize; 438 uint64_t coffset; 439 440 coffset = cluster_offset & s->cluster_offset_mask; 441 if (s->cluster_cache_offset != coffset) { 442 csize = cluster_offset >> (63 - s->cluster_bits); 443 csize &= (s->cluster_size - 1); 444 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 445 if (ret != csize) 446 return -1; 447 if (decompress_buffer(s->cluster_cache, s->cluster_size, 448 s->cluster_data, csize) < 0) { 449 return -1; 450 } 451 s->cluster_cache_offset = coffset; 452 } 453 return 0; 454 } 455 456 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 457 int nb_sectors, QEMUIOVector *qiov) 458 { 459 BDRVQcowState *s = bs->opaque; 460 int index_in_cluster; 461 int ret = 0, n; 462 uint64_t cluster_offset; 463 struct iovec hd_iov; 464 QEMUIOVector hd_qiov; 465 uint8_t *buf; 466 void *orig_buf; 467 468 if (qiov->niov > 1) { 469 buf = orig_buf = qemu_blockalign(bs, qiov->size); 470 } else { 471 orig_buf = NULL; 472 buf = (uint8_t *)qiov->iov->iov_base; 473 } 474 475 qemu_co_mutex_lock(&s->lock); 476 477 while (nb_sectors != 0) { 478 /* prepare next request */ 479 cluster_offset = get_cluster_offset(bs, sector_num << 9, 480 0, 0, 0, 0); 481 index_in_cluster = sector_num & (s->cluster_sectors - 1); 482 n = s->cluster_sectors - index_in_cluster; 483 if (n > nb_sectors) { 484 n = nb_sectors; 485 } 486 487 if (!cluster_offset) { 488 if (bs->backing_hd) { 489 /* read from the base image */ 490 hd_iov.iov_base = (void *)buf; 491 hd_iov.iov_len = n * 512; 492 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 493 qemu_co_mutex_unlock(&s->lock); 494 ret = bdrv_co_readv(bs->backing_hd, sector_num, 495 n, &hd_qiov); 496 qemu_co_mutex_lock(&s->lock); 497 if (ret < 0) { 498 goto fail; 499 } 500 } else { 501 /* Note: in this case, no need to wait */ 502 memset(buf, 0, 512 * n); 503 } 504 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 505 /* add AIO support for compressed blocks ? */ 506 if (decompress_cluster(bs, cluster_offset) < 0) { 507 goto fail; 508 } 509 memcpy(buf, 510 s->cluster_cache + index_in_cluster * 512, 512 * n); 511 } else { 512 if ((cluster_offset & 511) != 0) { 513 goto fail; 514 } 515 hd_iov.iov_base = (void *)buf; 516 hd_iov.iov_len = n * 512; 517 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 518 qemu_co_mutex_unlock(&s->lock); 519 ret = bdrv_co_readv(bs->file, 520 (cluster_offset >> 9) + index_in_cluster, 521 n, &hd_qiov); 522 qemu_co_mutex_lock(&s->lock); 523 if (ret < 0) { 524 break; 525 } 526 if (s->crypt_method) { 527 encrypt_sectors(s, sector_num, buf, buf, 528 n, 0, 529 &s->aes_decrypt_key); 530 } 531 } 532 ret = 0; 533 534 nb_sectors -= n; 535 sector_num += n; 536 buf += n * 512; 537 } 538 539 done: 540 qemu_co_mutex_unlock(&s->lock); 541 542 if (qiov->niov > 1) { 543 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 544 qemu_vfree(orig_buf); 545 } 546 547 return ret; 548 549 fail: 550 ret = -EIO; 551 goto done; 552 } 553 554 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 555 int nb_sectors, QEMUIOVector *qiov) 556 { 557 BDRVQcowState *s = bs->opaque; 558 int index_in_cluster; 559 uint64_t cluster_offset; 560 const uint8_t *src_buf; 561 int ret = 0, n; 562 uint8_t *cluster_data = NULL; 563 struct iovec hd_iov; 564 QEMUIOVector hd_qiov; 565 uint8_t *buf; 566 void *orig_buf; 567 568 s->cluster_cache_offset = -1; /* disable compressed cache */ 569 570 if (qiov->niov > 1) { 571 buf = orig_buf = qemu_blockalign(bs, qiov->size); 572 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 573 } else { 574 orig_buf = NULL; 575 buf = (uint8_t *)qiov->iov->iov_base; 576 } 577 578 qemu_co_mutex_lock(&s->lock); 579 580 while (nb_sectors != 0) { 581 582 index_in_cluster = sector_num & (s->cluster_sectors - 1); 583 n = s->cluster_sectors - index_in_cluster; 584 if (n > nb_sectors) { 585 n = nb_sectors; 586 } 587 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 588 index_in_cluster, 589 index_in_cluster + n); 590 if (!cluster_offset || (cluster_offset & 511) != 0) { 591 ret = -EIO; 592 break; 593 } 594 if (s->crypt_method) { 595 if (!cluster_data) { 596 cluster_data = g_malloc0(s->cluster_size); 597 } 598 encrypt_sectors(s, sector_num, cluster_data, buf, 599 n, 1, &s->aes_encrypt_key); 600 src_buf = cluster_data; 601 } else { 602 src_buf = buf; 603 } 604 605 hd_iov.iov_base = (void *)src_buf; 606 hd_iov.iov_len = n * 512; 607 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 608 qemu_co_mutex_unlock(&s->lock); 609 ret = bdrv_co_writev(bs->file, 610 (cluster_offset >> 9) + index_in_cluster, 611 n, &hd_qiov); 612 qemu_co_mutex_lock(&s->lock); 613 if (ret < 0) { 614 break; 615 } 616 ret = 0; 617 618 nb_sectors -= n; 619 sector_num += n; 620 buf += n * 512; 621 } 622 qemu_co_mutex_unlock(&s->lock); 623 624 if (qiov->niov > 1) { 625 qemu_vfree(orig_buf); 626 } 627 g_free(cluster_data); 628 629 return ret; 630 } 631 632 static void qcow_close(BlockDriverState *bs) 633 { 634 BDRVQcowState *s = bs->opaque; 635 636 g_free(s->l1_table); 637 g_free(s->l2_cache); 638 g_free(s->cluster_cache); 639 g_free(s->cluster_data); 640 641 migrate_del_blocker(s->migration_blocker); 642 error_free(s->migration_blocker); 643 } 644 645 static int qcow_create(const char *filename, QEMUOptionParameter *options) 646 { 647 int header_size, backing_filename_len, l1_size, shift, i; 648 QCowHeader header; 649 uint8_t *tmp; 650 int64_t total_size = 0; 651 const char *backing_file = NULL; 652 int flags = 0; 653 int ret; 654 BlockDriverState *qcow_bs; 655 656 /* Read out options */ 657 while (options && options->name) { 658 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 659 total_size = options->value.n / 512; 660 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 661 backing_file = options->value.s; 662 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 663 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 664 } 665 options++; 666 } 667 668 ret = bdrv_create_file(filename, options); 669 if (ret < 0) { 670 return ret; 671 } 672 673 ret = bdrv_file_open(&qcow_bs, filename, BDRV_O_RDWR); 674 if (ret < 0) { 675 return ret; 676 } 677 678 ret = bdrv_truncate(qcow_bs, 0); 679 if (ret < 0) { 680 goto exit; 681 } 682 683 memset(&header, 0, sizeof(header)); 684 header.magic = cpu_to_be32(QCOW_MAGIC); 685 header.version = cpu_to_be32(QCOW_VERSION); 686 header.size = cpu_to_be64(total_size * 512); 687 header_size = sizeof(header); 688 backing_filename_len = 0; 689 if (backing_file) { 690 if (strcmp(backing_file, "fat:")) { 691 header.backing_file_offset = cpu_to_be64(header_size); 692 backing_filename_len = strlen(backing_file); 693 header.backing_file_size = cpu_to_be32(backing_filename_len); 694 header_size += backing_filename_len; 695 } else { 696 /* special backing file for vvfat */ 697 backing_file = NULL; 698 } 699 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 700 unmodifyed sectors */ 701 header.l2_bits = 12; /* 32 KB L2 tables */ 702 } else { 703 header.cluster_bits = 12; /* 4 KB clusters */ 704 header.l2_bits = 9; /* 4 KB L2 tables */ 705 } 706 header_size = (header_size + 7) & ~7; 707 shift = header.cluster_bits + header.l2_bits; 708 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 709 710 header.l1_table_offset = cpu_to_be64(header_size); 711 if (flags & BLOCK_FLAG_ENCRYPT) { 712 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 713 } else { 714 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 715 } 716 717 /* write all the data */ 718 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 719 if (ret != sizeof(header)) { 720 goto exit; 721 } 722 723 if (backing_file) { 724 ret = bdrv_pwrite(qcow_bs, sizeof(header), 725 backing_file, backing_filename_len); 726 if (ret != backing_filename_len) { 727 goto exit; 728 } 729 } 730 731 tmp = g_malloc0(BDRV_SECTOR_SIZE); 732 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 733 BDRV_SECTOR_SIZE); i++) { 734 ret = bdrv_pwrite(qcow_bs, header_size + 735 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 736 if (ret != BDRV_SECTOR_SIZE) { 737 g_free(tmp); 738 goto exit; 739 } 740 } 741 742 g_free(tmp); 743 ret = 0; 744 exit: 745 bdrv_delete(qcow_bs); 746 return ret; 747 } 748 749 static int qcow_make_empty(BlockDriverState *bs) 750 { 751 BDRVQcowState *s = bs->opaque; 752 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 753 int ret; 754 755 memset(s->l1_table, 0, l1_length); 756 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 757 l1_length) < 0) 758 return -1; 759 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 760 if (ret < 0) 761 return ret; 762 763 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 764 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 765 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 766 767 return 0; 768 } 769 770 /* XXX: put compressed sectors first, then all the cluster aligned 771 tables to avoid losing bytes in alignment */ 772 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 773 const uint8_t *buf, int nb_sectors) 774 { 775 BDRVQcowState *s = bs->opaque; 776 z_stream strm; 777 int ret, out_len; 778 uint8_t *out_buf; 779 uint64_t cluster_offset; 780 781 if (nb_sectors != s->cluster_sectors) 782 return -EINVAL; 783 784 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 785 786 /* best compression, small window, no zlib header */ 787 memset(&strm, 0, sizeof(strm)); 788 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 789 Z_DEFLATED, -12, 790 9, Z_DEFAULT_STRATEGY); 791 if (ret != 0) { 792 ret = -EINVAL; 793 goto fail; 794 } 795 796 strm.avail_in = s->cluster_size; 797 strm.next_in = (uint8_t *)buf; 798 strm.avail_out = s->cluster_size; 799 strm.next_out = out_buf; 800 801 ret = deflate(&strm, Z_FINISH); 802 if (ret != Z_STREAM_END && ret != Z_OK) { 803 deflateEnd(&strm); 804 ret = -EINVAL; 805 goto fail; 806 } 807 out_len = strm.next_out - out_buf; 808 809 deflateEnd(&strm); 810 811 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 812 /* could not compress: write normal cluster */ 813 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 814 if (ret < 0) { 815 goto fail; 816 } 817 } else { 818 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 819 out_len, 0, 0); 820 if (cluster_offset == 0) { 821 ret = -EIO; 822 goto fail; 823 } 824 825 cluster_offset &= s->cluster_offset_mask; 826 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 827 if (ret < 0) { 828 goto fail; 829 } 830 } 831 832 ret = 0; 833 fail: 834 g_free(out_buf); 835 return ret; 836 } 837 838 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 839 { 840 BDRVQcowState *s = bs->opaque; 841 bdi->cluster_size = s->cluster_size; 842 return 0; 843 } 844 845 846 static QEMUOptionParameter qcow_create_options[] = { 847 { 848 .name = BLOCK_OPT_SIZE, 849 .type = OPT_SIZE, 850 .help = "Virtual disk size" 851 }, 852 { 853 .name = BLOCK_OPT_BACKING_FILE, 854 .type = OPT_STRING, 855 .help = "File name of a base image" 856 }, 857 { 858 .name = BLOCK_OPT_ENCRYPT, 859 .type = OPT_FLAG, 860 .help = "Encrypt the image" 861 }, 862 { NULL } 863 }; 864 865 static BlockDriver bdrv_qcow = { 866 .format_name = "qcow", 867 .instance_size = sizeof(BDRVQcowState), 868 .bdrv_probe = qcow_probe, 869 .bdrv_open = qcow_open, 870 .bdrv_close = qcow_close, 871 .bdrv_create = qcow_create, 872 873 .bdrv_co_readv = qcow_co_readv, 874 .bdrv_co_writev = qcow_co_writev, 875 .bdrv_co_is_allocated = qcow_co_is_allocated, 876 877 .bdrv_set_key = qcow_set_key, 878 .bdrv_make_empty = qcow_make_empty, 879 .bdrv_write_compressed = qcow_write_compressed, 880 .bdrv_get_info = qcow_get_info, 881 882 .create_options = qcow_create_options, 883 }; 884 885 static void bdrv_qcow_init(void) 886 { 887 bdrv_register(&bdrv_qcow); 888 } 889 890 block_init(bdrv_qcow_init); 891