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; 99 QCowHeader header; 100 101 if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header)) 102 goto fail; 103 be32_to_cpus(&header.magic); 104 be32_to_cpus(&header.version); 105 be64_to_cpus(&header.backing_file_offset); 106 be32_to_cpus(&header.backing_file_size); 107 be32_to_cpus(&header.mtime); 108 be64_to_cpus(&header.size); 109 be32_to_cpus(&header.crypt_method); 110 be64_to_cpus(&header.l1_table_offset); 111 112 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION) 113 goto fail; 114 if (header.size <= 1 || header.cluster_bits < 9) 115 goto fail; 116 if (header.crypt_method > QCOW_CRYPT_AES) 117 goto fail; 118 s->crypt_method_header = header.crypt_method; 119 if (s->crypt_method_header) 120 bs->encrypted = 1; 121 s->cluster_bits = header.cluster_bits; 122 s->cluster_size = 1 << s->cluster_bits; 123 s->cluster_sectors = 1 << (s->cluster_bits - 9); 124 s->l2_bits = header.l2_bits; 125 s->l2_size = 1 << s->l2_bits; 126 bs->total_sectors = header.size / 512; 127 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 128 129 /* read the level 1 table */ 130 shift = s->cluster_bits + s->l2_bits; 131 s->l1_size = (header.size + (1LL << shift) - 1) >> shift; 132 133 s->l1_table_offset = header.l1_table_offset; 134 s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); 135 if (!s->l1_table) 136 goto fail; 137 if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != 138 s->l1_size * sizeof(uint64_t)) 139 goto fail; 140 for(i = 0;i < s->l1_size; i++) { 141 be64_to_cpus(&s->l1_table[i]); 142 } 143 /* alloc L2 cache */ 144 s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 145 if (!s->l2_cache) 146 goto fail; 147 s->cluster_cache = g_malloc(s->cluster_size); 148 if (!s->cluster_cache) 149 goto fail; 150 s->cluster_data = g_malloc(s->cluster_size); 151 if (!s->cluster_data) 152 goto fail; 153 s->cluster_cache_offset = -1; 154 155 /* read the backing file name */ 156 if (header.backing_file_offset != 0) { 157 len = header.backing_file_size; 158 if (len > 1023) 159 len = 1023; 160 if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len) 161 goto fail; 162 bs->backing_file[len] = '\0'; 163 } 164 165 /* Disable migration when qcow images are used */ 166 error_set(&s->migration_blocker, 167 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 168 "qcow", bs->device_name, "live migration"); 169 migrate_add_blocker(s->migration_blocker); 170 171 qemu_co_mutex_init(&s->lock); 172 return 0; 173 174 fail: 175 g_free(s->l1_table); 176 g_free(s->l2_cache); 177 g_free(s->cluster_cache); 178 g_free(s->cluster_data); 179 return -1; 180 } 181 182 static int qcow_set_key(BlockDriverState *bs, const char *key) 183 { 184 BDRVQcowState *s = bs->opaque; 185 uint8_t keybuf[16]; 186 int len, i; 187 188 memset(keybuf, 0, 16); 189 len = strlen(key); 190 if (len > 16) 191 len = 16; 192 /* XXX: we could compress the chars to 7 bits to increase 193 entropy */ 194 for(i = 0;i < len;i++) { 195 keybuf[i] = key[i]; 196 } 197 s->crypt_method = s->crypt_method_header; 198 199 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 200 return -1; 201 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 202 return -1; 203 return 0; 204 } 205 206 /* The crypt function is compatible with the linux cryptoloop 207 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 208 supported */ 209 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 210 uint8_t *out_buf, const uint8_t *in_buf, 211 int nb_sectors, int enc, 212 const AES_KEY *key) 213 { 214 union { 215 uint64_t ll[2]; 216 uint8_t b[16]; 217 } ivec; 218 int i; 219 220 for(i = 0; i < nb_sectors; i++) { 221 ivec.ll[0] = cpu_to_le64(sector_num); 222 ivec.ll[1] = 0; 223 AES_cbc_encrypt(in_buf, out_buf, 512, key, 224 ivec.b, enc); 225 sector_num++; 226 in_buf += 512; 227 out_buf += 512; 228 } 229 } 230 231 /* 'allocate' is: 232 * 233 * 0 to not allocate. 234 * 235 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 236 * 'n_end') 237 * 238 * 2 to allocate a compressed cluster of size 239 * 'compressed_size'. 'compressed_size' must be > 0 and < 240 * cluster_size 241 * 242 * return 0 if not allocated. 243 */ 244 static uint64_t get_cluster_offset(BlockDriverState *bs, 245 uint64_t offset, int allocate, 246 int compressed_size, 247 int n_start, int n_end) 248 { 249 BDRVQcowState *s = bs->opaque; 250 int min_index, i, j, l1_index, l2_index; 251 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 252 uint32_t min_count; 253 int new_l2_table; 254 255 l1_index = offset >> (s->l2_bits + s->cluster_bits); 256 l2_offset = s->l1_table[l1_index]; 257 new_l2_table = 0; 258 if (!l2_offset) { 259 if (!allocate) 260 return 0; 261 /* allocate a new l2 entry */ 262 l2_offset = bdrv_getlength(bs->file); 263 /* round to cluster size */ 264 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 265 /* update the L1 entry */ 266 s->l1_table[l1_index] = l2_offset; 267 tmp = cpu_to_be64(l2_offset); 268 if (bdrv_pwrite_sync(bs->file, 269 s->l1_table_offset + l1_index * sizeof(tmp), 270 &tmp, sizeof(tmp)) < 0) 271 return 0; 272 new_l2_table = 1; 273 } 274 for(i = 0; i < L2_CACHE_SIZE; i++) { 275 if (l2_offset == s->l2_cache_offsets[i]) { 276 /* increment the hit count */ 277 if (++s->l2_cache_counts[i] == 0xffffffff) { 278 for(j = 0; j < L2_CACHE_SIZE; j++) { 279 s->l2_cache_counts[j] >>= 1; 280 } 281 } 282 l2_table = s->l2_cache + (i << s->l2_bits); 283 goto found; 284 } 285 } 286 /* not found: load a new entry in the least used one */ 287 min_index = 0; 288 min_count = 0xffffffff; 289 for(i = 0; i < L2_CACHE_SIZE; i++) { 290 if (s->l2_cache_counts[i] < min_count) { 291 min_count = s->l2_cache_counts[i]; 292 min_index = i; 293 } 294 } 295 l2_table = s->l2_cache + (min_index << s->l2_bits); 296 if (new_l2_table) { 297 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 298 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 299 s->l2_size * sizeof(uint64_t)) < 0) 300 return 0; 301 } else { 302 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 303 s->l2_size * sizeof(uint64_t)) 304 return 0; 305 } 306 s->l2_cache_offsets[min_index] = l2_offset; 307 s->l2_cache_counts[min_index] = 1; 308 found: 309 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 310 cluster_offset = be64_to_cpu(l2_table[l2_index]); 311 if (!cluster_offset || 312 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 313 if (!allocate) 314 return 0; 315 /* allocate a new cluster */ 316 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 317 (n_end - n_start) < s->cluster_sectors) { 318 /* if the cluster is already compressed, we must 319 decompress it in the case it is not completely 320 overwritten */ 321 if (decompress_cluster(bs, cluster_offset) < 0) 322 return 0; 323 cluster_offset = bdrv_getlength(bs->file); 324 cluster_offset = (cluster_offset + s->cluster_size - 1) & 325 ~(s->cluster_size - 1); 326 /* write the cluster content */ 327 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 328 s->cluster_size) 329 return -1; 330 } else { 331 cluster_offset = bdrv_getlength(bs->file); 332 if (allocate == 1) { 333 /* round to cluster size */ 334 cluster_offset = (cluster_offset + s->cluster_size - 1) & 335 ~(s->cluster_size - 1); 336 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 337 /* if encrypted, we must initialize the cluster 338 content which won't be written */ 339 if (s->crypt_method && 340 (n_end - n_start) < s->cluster_sectors) { 341 uint64_t start_sect; 342 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 343 memset(s->cluster_data + 512, 0x00, 512); 344 for(i = 0; i < s->cluster_sectors; i++) { 345 if (i < n_start || i >= n_end) { 346 encrypt_sectors(s, start_sect + i, 347 s->cluster_data, 348 s->cluster_data + 512, 1, 1, 349 &s->aes_encrypt_key); 350 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 351 s->cluster_data, 512) != 512) 352 return -1; 353 } 354 } 355 } 356 } else if (allocate == 2) { 357 cluster_offset |= QCOW_OFLAG_COMPRESSED | 358 (uint64_t)compressed_size << (63 - s->cluster_bits); 359 } 360 } 361 /* update L2 table */ 362 tmp = cpu_to_be64(cluster_offset); 363 l2_table[l2_index] = tmp; 364 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 365 &tmp, sizeof(tmp)) < 0) 366 return 0; 367 } 368 return cluster_offset; 369 } 370 371 static int coroutine_fn qcow_co_is_allocated(BlockDriverState *bs, 372 int64_t sector_num, int nb_sectors, int *pnum) 373 { 374 BDRVQcowState *s = bs->opaque; 375 int index_in_cluster, n; 376 uint64_t cluster_offset; 377 378 qemu_co_mutex_lock(&s->lock); 379 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 380 qemu_co_mutex_unlock(&s->lock); 381 index_in_cluster = sector_num & (s->cluster_sectors - 1); 382 n = s->cluster_sectors - index_in_cluster; 383 if (n > nb_sectors) 384 n = nb_sectors; 385 *pnum = n; 386 return (cluster_offset != 0); 387 } 388 389 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 390 const uint8_t *buf, int buf_size) 391 { 392 z_stream strm1, *strm = &strm1; 393 int ret, out_len; 394 395 memset(strm, 0, sizeof(*strm)); 396 397 strm->next_in = (uint8_t *)buf; 398 strm->avail_in = buf_size; 399 strm->next_out = out_buf; 400 strm->avail_out = out_buf_size; 401 402 ret = inflateInit2(strm, -12); 403 if (ret != Z_OK) 404 return -1; 405 ret = inflate(strm, Z_FINISH); 406 out_len = strm->next_out - out_buf; 407 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 408 out_len != out_buf_size) { 409 inflateEnd(strm); 410 return -1; 411 } 412 inflateEnd(strm); 413 return 0; 414 } 415 416 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 417 { 418 BDRVQcowState *s = bs->opaque; 419 int ret, csize; 420 uint64_t coffset; 421 422 coffset = cluster_offset & s->cluster_offset_mask; 423 if (s->cluster_cache_offset != coffset) { 424 csize = cluster_offset >> (63 - s->cluster_bits); 425 csize &= (s->cluster_size - 1); 426 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 427 if (ret != csize) 428 return -1; 429 if (decompress_buffer(s->cluster_cache, s->cluster_size, 430 s->cluster_data, csize) < 0) { 431 return -1; 432 } 433 s->cluster_cache_offset = coffset; 434 } 435 return 0; 436 } 437 438 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 439 int nb_sectors, QEMUIOVector *qiov) 440 { 441 BDRVQcowState *s = bs->opaque; 442 int index_in_cluster; 443 int ret = 0, n; 444 uint64_t cluster_offset; 445 struct iovec hd_iov; 446 QEMUIOVector hd_qiov; 447 uint8_t *buf; 448 void *orig_buf; 449 450 if (qiov->niov > 1) { 451 buf = orig_buf = qemu_blockalign(bs, qiov->size); 452 } else { 453 orig_buf = NULL; 454 buf = (uint8_t *)qiov->iov->iov_base; 455 } 456 457 qemu_co_mutex_lock(&s->lock); 458 459 while (nb_sectors != 0) { 460 /* prepare next request */ 461 cluster_offset = get_cluster_offset(bs, sector_num << 9, 462 0, 0, 0, 0); 463 index_in_cluster = sector_num & (s->cluster_sectors - 1); 464 n = s->cluster_sectors - index_in_cluster; 465 if (n > nb_sectors) { 466 n = nb_sectors; 467 } 468 469 if (!cluster_offset) { 470 if (bs->backing_hd) { 471 /* read from the base image */ 472 hd_iov.iov_base = (void *)buf; 473 hd_iov.iov_len = n * 512; 474 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 475 qemu_co_mutex_unlock(&s->lock); 476 ret = bdrv_co_readv(bs->backing_hd, sector_num, 477 n, &hd_qiov); 478 qemu_co_mutex_lock(&s->lock); 479 if (ret < 0) { 480 goto fail; 481 } 482 } else { 483 /* Note: in this case, no need to wait */ 484 memset(buf, 0, 512 * n); 485 } 486 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 487 /* add AIO support for compressed blocks ? */ 488 if (decompress_cluster(bs, cluster_offset) < 0) { 489 goto fail; 490 } 491 memcpy(buf, 492 s->cluster_cache + index_in_cluster * 512, 512 * n); 493 } else { 494 if ((cluster_offset & 511) != 0) { 495 goto fail; 496 } 497 hd_iov.iov_base = (void *)buf; 498 hd_iov.iov_len = n * 512; 499 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 500 qemu_co_mutex_unlock(&s->lock); 501 ret = bdrv_co_readv(bs->file, 502 (cluster_offset >> 9) + index_in_cluster, 503 n, &hd_qiov); 504 qemu_co_mutex_lock(&s->lock); 505 if (ret < 0) { 506 break; 507 } 508 if (s->crypt_method) { 509 encrypt_sectors(s, sector_num, buf, buf, 510 n, 0, 511 &s->aes_decrypt_key); 512 } 513 } 514 ret = 0; 515 516 nb_sectors -= n; 517 sector_num += n; 518 buf += n * 512; 519 } 520 521 done: 522 qemu_co_mutex_unlock(&s->lock); 523 524 if (qiov->niov > 1) { 525 qemu_iovec_from_buffer(qiov, orig_buf, qiov->size); 526 qemu_vfree(orig_buf); 527 } 528 529 return ret; 530 531 fail: 532 ret = -EIO; 533 goto done; 534 } 535 536 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 537 int nb_sectors, QEMUIOVector *qiov) 538 { 539 BDRVQcowState *s = bs->opaque; 540 int index_in_cluster; 541 uint64_t cluster_offset; 542 const uint8_t *src_buf; 543 int ret = 0, n; 544 uint8_t *cluster_data = NULL; 545 struct iovec hd_iov; 546 QEMUIOVector hd_qiov; 547 uint8_t *buf; 548 void *orig_buf; 549 550 s->cluster_cache_offset = -1; /* disable compressed cache */ 551 552 if (qiov->niov > 1) { 553 buf = orig_buf = qemu_blockalign(bs, qiov->size); 554 qemu_iovec_to_buffer(qiov, buf); 555 } else { 556 orig_buf = NULL; 557 buf = (uint8_t *)qiov->iov->iov_base; 558 } 559 560 qemu_co_mutex_lock(&s->lock); 561 562 while (nb_sectors != 0) { 563 564 index_in_cluster = sector_num & (s->cluster_sectors - 1); 565 n = s->cluster_sectors - index_in_cluster; 566 if (n > nb_sectors) { 567 n = nb_sectors; 568 } 569 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 570 index_in_cluster, 571 index_in_cluster + n); 572 if (!cluster_offset || (cluster_offset & 511) != 0) { 573 ret = -EIO; 574 break; 575 } 576 if (s->crypt_method) { 577 if (!cluster_data) { 578 cluster_data = g_malloc0(s->cluster_size); 579 } 580 encrypt_sectors(s, sector_num, cluster_data, buf, 581 n, 1, &s->aes_encrypt_key); 582 src_buf = cluster_data; 583 } else { 584 src_buf = buf; 585 } 586 587 hd_iov.iov_base = (void *)src_buf; 588 hd_iov.iov_len = n * 512; 589 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 590 qemu_co_mutex_unlock(&s->lock); 591 ret = bdrv_co_writev(bs->file, 592 (cluster_offset >> 9) + index_in_cluster, 593 n, &hd_qiov); 594 qemu_co_mutex_lock(&s->lock); 595 if (ret < 0) { 596 break; 597 } 598 ret = 0; 599 600 nb_sectors -= n; 601 sector_num += n; 602 buf += n * 512; 603 } 604 qemu_co_mutex_unlock(&s->lock); 605 606 if (qiov->niov > 1) { 607 qemu_vfree(orig_buf); 608 } 609 g_free(cluster_data); 610 611 return ret; 612 } 613 614 static void qcow_close(BlockDriverState *bs) 615 { 616 BDRVQcowState *s = bs->opaque; 617 618 g_free(s->l1_table); 619 g_free(s->l2_cache); 620 g_free(s->cluster_cache); 621 g_free(s->cluster_data); 622 623 migrate_del_blocker(s->migration_blocker); 624 error_free(s->migration_blocker); 625 } 626 627 static int qcow_create(const char *filename, QEMUOptionParameter *options) 628 { 629 int fd, header_size, backing_filename_len, l1_size, i, shift; 630 QCowHeader header; 631 uint64_t tmp; 632 int64_t total_size = 0; 633 const char *backing_file = NULL; 634 int flags = 0; 635 int ret; 636 637 /* Read out options */ 638 while (options && options->name) { 639 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 640 total_size = options->value.n / 512; 641 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 642 backing_file = options->value.s; 643 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 644 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 645 } 646 options++; 647 } 648 649 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); 650 if (fd < 0) 651 return -errno; 652 memset(&header, 0, sizeof(header)); 653 header.magic = cpu_to_be32(QCOW_MAGIC); 654 header.version = cpu_to_be32(QCOW_VERSION); 655 header.size = cpu_to_be64(total_size * 512); 656 header_size = sizeof(header); 657 backing_filename_len = 0; 658 if (backing_file) { 659 if (strcmp(backing_file, "fat:")) { 660 header.backing_file_offset = cpu_to_be64(header_size); 661 backing_filename_len = strlen(backing_file); 662 header.backing_file_size = cpu_to_be32(backing_filename_len); 663 header_size += backing_filename_len; 664 } else { 665 /* special backing file for vvfat */ 666 backing_file = NULL; 667 } 668 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 669 unmodifyed sectors */ 670 header.l2_bits = 12; /* 32 KB L2 tables */ 671 } else { 672 header.cluster_bits = 12; /* 4 KB clusters */ 673 header.l2_bits = 9; /* 4 KB L2 tables */ 674 } 675 header_size = (header_size + 7) & ~7; 676 shift = header.cluster_bits + header.l2_bits; 677 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 678 679 header.l1_table_offset = cpu_to_be64(header_size); 680 if (flags & BLOCK_FLAG_ENCRYPT) { 681 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 682 } else { 683 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 684 } 685 686 /* write all the data */ 687 ret = qemu_write_full(fd, &header, sizeof(header)); 688 if (ret != sizeof(header)) { 689 ret = -errno; 690 goto exit; 691 } 692 693 if (backing_file) { 694 ret = qemu_write_full(fd, backing_file, backing_filename_len); 695 if (ret != backing_filename_len) { 696 ret = -errno; 697 goto exit; 698 } 699 700 } 701 lseek(fd, header_size, SEEK_SET); 702 tmp = 0; 703 for(i = 0;i < l1_size; i++) { 704 ret = qemu_write_full(fd, &tmp, sizeof(tmp)); 705 if (ret != sizeof(tmp)) { 706 ret = -errno; 707 goto exit; 708 } 709 } 710 711 ret = 0; 712 exit: 713 close(fd); 714 return ret; 715 } 716 717 static int qcow_make_empty(BlockDriverState *bs) 718 { 719 BDRVQcowState *s = bs->opaque; 720 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 721 int ret; 722 723 memset(s->l1_table, 0, l1_length); 724 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 725 l1_length) < 0) 726 return -1; 727 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 728 if (ret < 0) 729 return ret; 730 731 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 732 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 733 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 734 735 return 0; 736 } 737 738 /* XXX: put compressed sectors first, then all the cluster aligned 739 tables to avoid losing bytes in alignment */ 740 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 741 const uint8_t *buf, int nb_sectors) 742 { 743 BDRVQcowState *s = bs->opaque; 744 z_stream strm; 745 int ret, out_len; 746 uint8_t *out_buf; 747 uint64_t cluster_offset; 748 749 if (nb_sectors != s->cluster_sectors) 750 return -EINVAL; 751 752 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 753 754 /* best compression, small window, no zlib header */ 755 memset(&strm, 0, sizeof(strm)); 756 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 757 Z_DEFLATED, -12, 758 9, Z_DEFAULT_STRATEGY); 759 if (ret != 0) { 760 ret = -EINVAL; 761 goto fail; 762 } 763 764 strm.avail_in = s->cluster_size; 765 strm.next_in = (uint8_t *)buf; 766 strm.avail_out = s->cluster_size; 767 strm.next_out = out_buf; 768 769 ret = deflate(&strm, Z_FINISH); 770 if (ret != Z_STREAM_END && ret != Z_OK) { 771 deflateEnd(&strm); 772 ret = -EINVAL; 773 goto fail; 774 } 775 out_len = strm.next_out - out_buf; 776 777 deflateEnd(&strm); 778 779 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 780 /* could not compress: write normal cluster */ 781 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 782 if (ret < 0) { 783 goto fail; 784 } 785 } else { 786 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 787 out_len, 0, 0); 788 if (cluster_offset == 0) { 789 ret = -EIO; 790 goto fail; 791 } 792 793 cluster_offset &= s->cluster_offset_mask; 794 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 795 if (ret < 0) { 796 goto fail; 797 } 798 } 799 800 ret = 0; 801 fail: 802 g_free(out_buf); 803 return ret; 804 } 805 806 static coroutine_fn int qcow_co_flush(BlockDriverState *bs) 807 { 808 return bdrv_co_flush(bs->file); 809 } 810 811 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 812 { 813 BDRVQcowState *s = bs->opaque; 814 bdi->cluster_size = s->cluster_size; 815 return 0; 816 } 817 818 819 static QEMUOptionParameter qcow_create_options[] = { 820 { 821 .name = BLOCK_OPT_SIZE, 822 .type = OPT_SIZE, 823 .help = "Virtual disk size" 824 }, 825 { 826 .name = BLOCK_OPT_BACKING_FILE, 827 .type = OPT_STRING, 828 .help = "File name of a base image" 829 }, 830 { 831 .name = BLOCK_OPT_ENCRYPT, 832 .type = OPT_FLAG, 833 .help = "Encrypt the image" 834 }, 835 { NULL } 836 }; 837 838 static BlockDriver bdrv_qcow = { 839 .format_name = "qcow", 840 .instance_size = sizeof(BDRVQcowState), 841 .bdrv_probe = qcow_probe, 842 .bdrv_open = qcow_open, 843 .bdrv_close = qcow_close, 844 .bdrv_create = qcow_create, 845 846 .bdrv_co_readv = qcow_co_readv, 847 .bdrv_co_writev = qcow_co_writev, 848 .bdrv_co_flush_to_disk = qcow_co_flush, 849 .bdrv_co_is_allocated = qcow_co_is_allocated, 850 851 .bdrv_set_key = qcow_set_key, 852 .bdrv_make_empty = qcow_make_empty, 853 .bdrv_write_compressed = qcow_write_compressed, 854 .bdrv_get_info = qcow_get_info, 855 856 .create_options = qcow_create_options, 857 }; 858 859 static void bdrv_qcow_init(void) 860 { 861 bdrv_register(&bdrv_qcow); 862 } 863 864 block_init(bdrv_qcow_init); 865