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/block_int.h" 26 #include "qemu/module.h" 27 #include <zlib.h> 28 #include "qemu/aes.h" 29 #include "migration/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, QDict *options, 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 = -EMEDIUMTYPE; 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 } 199 200 201 /* We have nothing to do for QCOW reopen, stubs just return 202 * success */ 203 static int qcow_reopen_prepare(BDRVReopenState *state, 204 BlockReopenQueue *queue, Error **errp) 205 { 206 return 0; 207 } 208 209 static int qcow_set_key(BlockDriverState *bs, const char *key) 210 { 211 BDRVQcowState *s = bs->opaque; 212 uint8_t keybuf[16]; 213 int len, i; 214 215 memset(keybuf, 0, 16); 216 len = strlen(key); 217 if (len > 16) 218 len = 16; 219 /* XXX: we could compress the chars to 7 bits to increase 220 entropy */ 221 for(i = 0;i < len;i++) { 222 keybuf[i] = key[i]; 223 } 224 s->crypt_method = s->crypt_method_header; 225 226 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 227 return -1; 228 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 229 return -1; 230 return 0; 231 } 232 233 /* The crypt function is compatible with the linux cryptoloop 234 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 235 supported */ 236 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 237 uint8_t *out_buf, const uint8_t *in_buf, 238 int nb_sectors, int enc, 239 const AES_KEY *key) 240 { 241 union { 242 uint64_t ll[2]; 243 uint8_t b[16]; 244 } ivec; 245 int i; 246 247 for(i = 0; i < nb_sectors; i++) { 248 ivec.ll[0] = cpu_to_le64(sector_num); 249 ivec.ll[1] = 0; 250 AES_cbc_encrypt(in_buf, out_buf, 512, key, 251 ivec.b, enc); 252 sector_num++; 253 in_buf += 512; 254 out_buf += 512; 255 } 256 } 257 258 /* 'allocate' is: 259 * 260 * 0 to not allocate. 261 * 262 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 263 * 'n_end') 264 * 265 * 2 to allocate a compressed cluster of size 266 * 'compressed_size'. 'compressed_size' must be > 0 and < 267 * cluster_size 268 * 269 * return 0 if not allocated. 270 */ 271 static uint64_t get_cluster_offset(BlockDriverState *bs, 272 uint64_t offset, int allocate, 273 int compressed_size, 274 int n_start, int n_end) 275 { 276 BDRVQcowState *s = bs->opaque; 277 int min_index, i, j, l1_index, l2_index; 278 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 279 uint32_t min_count; 280 int new_l2_table; 281 282 l1_index = offset >> (s->l2_bits + s->cluster_bits); 283 l2_offset = s->l1_table[l1_index]; 284 new_l2_table = 0; 285 if (!l2_offset) { 286 if (!allocate) 287 return 0; 288 /* allocate a new l2 entry */ 289 l2_offset = bdrv_getlength(bs->file); 290 /* round to cluster size */ 291 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 292 /* update the L1 entry */ 293 s->l1_table[l1_index] = l2_offset; 294 tmp = cpu_to_be64(l2_offset); 295 if (bdrv_pwrite_sync(bs->file, 296 s->l1_table_offset + l1_index * sizeof(tmp), 297 &tmp, sizeof(tmp)) < 0) 298 return 0; 299 new_l2_table = 1; 300 } 301 for(i = 0; i < L2_CACHE_SIZE; i++) { 302 if (l2_offset == s->l2_cache_offsets[i]) { 303 /* increment the hit count */ 304 if (++s->l2_cache_counts[i] == 0xffffffff) { 305 for(j = 0; j < L2_CACHE_SIZE; j++) { 306 s->l2_cache_counts[j] >>= 1; 307 } 308 } 309 l2_table = s->l2_cache + (i << s->l2_bits); 310 goto found; 311 } 312 } 313 /* not found: load a new entry in the least used one */ 314 min_index = 0; 315 min_count = 0xffffffff; 316 for(i = 0; i < L2_CACHE_SIZE; i++) { 317 if (s->l2_cache_counts[i] < min_count) { 318 min_count = s->l2_cache_counts[i]; 319 min_index = i; 320 } 321 } 322 l2_table = s->l2_cache + (min_index << s->l2_bits); 323 if (new_l2_table) { 324 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 325 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 326 s->l2_size * sizeof(uint64_t)) < 0) 327 return 0; 328 } else { 329 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 330 s->l2_size * sizeof(uint64_t)) 331 return 0; 332 } 333 s->l2_cache_offsets[min_index] = l2_offset; 334 s->l2_cache_counts[min_index] = 1; 335 found: 336 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 337 cluster_offset = be64_to_cpu(l2_table[l2_index]); 338 if (!cluster_offset || 339 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 340 if (!allocate) 341 return 0; 342 /* allocate a new cluster */ 343 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 344 (n_end - n_start) < s->cluster_sectors) { 345 /* if the cluster is already compressed, we must 346 decompress it in the case it is not completely 347 overwritten */ 348 if (decompress_cluster(bs, cluster_offset) < 0) 349 return 0; 350 cluster_offset = bdrv_getlength(bs->file); 351 cluster_offset = (cluster_offset + s->cluster_size - 1) & 352 ~(s->cluster_size - 1); 353 /* write the cluster content */ 354 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 355 s->cluster_size) 356 return -1; 357 } else { 358 cluster_offset = bdrv_getlength(bs->file); 359 if (allocate == 1) { 360 /* round to cluster size */ 361 cluster_offset = (cluster_offset + s->cluster_size - 1) & 362 ~(s->cluster_size - 1); 363 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 364 /* if encrypted, we must initialize the cluster 365 content which won't be written */ 366 if (s->crypt_method && 367 (n_end - n_start) < s->cluster_sectors) { 368 uint64_t start_sect; 369 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 370 memset(s->cluster_data + 512, 0x00, 512); 371 for(i = 0; i < s->cluster_sectors; i++) { 372 if (i < n_start || i >= n_end) { 373 encrypt_sectors(s, start_sect + i, 374 s->cluster_data, 375 s->cluster_data + 512, 1, 1, 376 &s->aes_encrypt_key); 377 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 378 s->cluster_data, 512) != 512) 379 return -1; 380 } 381 } 382 } 383 } else if (allocate == 2) { 384 cluster_offset |= QCOW_OFLAG_COMPRESSED | 385 (uint64_t)compressed_size << (63 - s->cluster_bits); 386 } 387 } 388 /* update L2 table */ 389 tmp = cpu_to_be64(cluster_offset); 390 l2_table[l2_index] = tmp; 391 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 392 &tmp, sizeof(tmp)) < 0) 393 return 0; 394 } 395 return cluster_offset; 396 } 397 398 static int coroutine_fn qcow_co_is_allocated(BlockDriverState *bs, 399 int64_t sector_num, int nb_sectors, int *pnum) 400 { 401 BDRVQcowState *s = bs->opaque; 402 int index_in_cluster, n; 403 uint64_t cluster_offset; 404 405 qemu_co_mutex_lock(&s->lock); 406 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 407 qemu_co_mutex_unlock(&s->lock); 408 index_in_cluster = sector_num & (s->cluster_sectors - 1); 409 n = s->cluster_sectors - index_in_cluster; 410 if (n > nb_sectors) 411 n = nb_sectors; 412 *pnum = n; 413 return (cluster_offset != 0); 414 } 415 416 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 417 const uint8_t *buf, int buf_size) 418 { 419 z_stream strm1, *strm = &strm1; 420 int ret, out_len; 421 422 memset(strm, 0, sizeof(*strm)); 423 424 strm->next_in = (uint8_t *)buf; 425 strm->avail_in = buf_size; 426 strm->next_out = out_buf; 427 strm->avail_out = out_buf_size; 428 429 ret = inflateInit2(strm, -12); 430 if (ret != Z_OK) 431 return -1; 432 ret = inflate(strm, Z_FINISH); 433 out_len = strm->next_out - out_buf; 434 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 435 out_len != out_buf_size) { 436 inflateEnd(strm); 437 return -1; 438 } 439 inflateEnd(strm); 440 return 0; 441 } 442 443 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 444 { 445 BDRVQcowState *s = bs->opaque; 446 int ret, csize; 447 uint64_t coffset; 448 449 coffset = cluster_offset & s->cluster_offset_mask; 450 if (s->cluster_cache_offset != coffset) { 451 csize = cluster_offset >> (63 - s->cluster_bits); 452 csize &= (s->cluster_size - 1); 453 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 454 if (ret != csize) 455 return -1; 456 if (decompress_buffer(s->cluster_cache, s->cluster_size, 457 s->cluster_data, csize) < 0) { 458 return -1; 459 } 460 s->cluster_cache_offset = coffset; 461 } 462 return 0; 463 } 464 465 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 466 int nb_sectors, QEMUIOVector *qiov) 467 { 468 BDRVQcowState *s = bs->opaque; 469 int index_in_cluster; 470 int ret = 0, n; 471 uint64_t cluster_offset; 472 struct iovec hd_iov; 473 QEMUIOVector hd_qiov; 474 uint8_t *buf; 475 void *orig_buf; 476 477 if (qiov->niov > 1) { 478 buf = orig_buf = qemu_blockalign(bs, qiov->size); 479 } else { 480 orig_buf = NULL; 481 buf = (uint8_t *)qiov->iov->iov_base; 482 } 483 484 qemu_co_mutex_lock(&s->lock); 485 486 while (nb_sectors != 0) { 487 /* prepare next request */ 488 cluster_offset = get_cluster_offset(bs, sector_num << 9, 489 0, 0, 0, 0); 490 index_in_cluster = sector_num & (s->cluster_sectors - 1); 491 n = s->cluster_sectors - index_in_cluster; 492 if (n > nb_sectors) { 493 n = nb_sectors; 494 } 495 496 if (!cluster_offset) { 497 if (bs->backing_hd) { 498 /* read from the base image */ 499 hd_iov.iov_base = (void *)buf; 500 hd_iov.iov_len = n * 512; 501 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 502 qemu_co_mutex_unlock(&s->lock); 503 ret = bdrv_co_readv(bs->backing_hd, sector_num, 504 n, &hd_qiov); 505 qemu_co_mutex_lock(&s->lock); 506 if (ret < 0) { 507 goto fail; 508 } 509 } else { 510 /* Note: in this case, no need to wait */ 511 memset(buf, 0, 512 * n); 512 } 513 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 514 /* add AIO support for compressed blocks ? */ 515 if (decompress_cluster(bs, cluster_offset) < 0) { 516 goto fail; 517 } 518 memcpy(buf, 519 s->cluster_cache + index_in_cluster * 512, 512 * n); 520 } else { 521 if ((cluster_offset & 511) != 0) { 522 goto fail; 523 } 524 hd_iov.iov_base = (void *)buf; 525 hd_iov.iov_len = n * 512; 526 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 527 qemu_co_mutex_unlock(&s->lock); 528 ret = bdrv_co_readv(bs->file, 529 (cluster_offset >> 9) + index_in_cluster, 530 n, &hd_qiov); 531 qemu_co_mutex_lock(&s->lock); 532 if (ret < 0) { 533 break; 534 } 535 if (s->crypt_method) { 536 encrypt_sectors(s, sector_num, buf, buf, 537 n, 0, 538 &s->aes_decrypt_key); 539 } 540 } 541 ret = 0; 542 543 nb_sectors -= n; 544 sector_num += n; 545 buf += n * 512; 546 } 547 548 done: 549 qemu_co_mutex_unlock(&s->lock); 550 551 if (qiov->niov > 1) { 552 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 553 qemu_vfree(orig_buf); 554 } 555 556 return ret; 557 558 fail: 559 ret = -EIO; 560 goto done; 561 } 562 563 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 564 int nb_sectors, QEMUIOVector *qiov) 565 { 566 BDRVQcowState *s = bs->opaque; 567 int index_in_cluster; 568 uint64_t cluster_offset; 569 const uint8_t *src_buf; 570 int ret = 0, n; 571 uint8_t *cluster_data = NULL; 572 struct iovec hd_iov; 573 QEMUIOVector hd_qiov; 574 uint8_t *buf; 575 void *orig_buf; 576 577 s->cluster_cache_offset = -1; /* disable compressed cache */ 578 579 if (qiov->niov > 1) { 580 buf = orig_buf = qemu_blockalign(bs, qiov->size); 581 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 582 } else { 583 orig_buf = NULL; 584 buf = (uint8_t *)qiov->iov->iov_base; 585 } 586 587 qemu_co_mutex_lock(&s->lock); 588 589 while (nb_sectors != 0) { 590 591 index_in_cluster = sector_num & (s->cluster_sectors - 1); 592 n = s->cluster_sectors - index_in_cluster; 593 if (n > nb_sectors) { 594 n = nb_sectors; 595 } 596 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 597 index_in_cluster, 598 index_in_cluster + n); 599 if (!cluster_offset || (cluster_offset & 511) != 0) { 600 ret = -EIO; 601 break; 602 } 603 if (s->crypt_method) { 604 if (!cluster_data) { 605 cluster_data = g_malloc0(s->cluster_size); 606 } 607 encrypt_sectors(s, sector_num, cluster_data, buf, 608 n, 1, &s->aes_encrypt_key); 609 src_buf = cluster_data; 610 } else { 611 src_buf = buf; 612 } 613 614 hd_iov.iov_base = (void *)src_buf; 615 hd_iov.iov_len = n * 512; 616 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 617 qemu_co_mutex_unlock(&s->lock); 618 ret = bdrv_co_writev(bs->file, 619 (cluster_offset >> 9) + index_in_cluster, 620 n, &hd_qiov); 621 qemu_co_mutex_lock(&s->lock); 622 if (ret < 0) { 623 break; 624 } 625 ret = 0; 626 627 nb_sectors -= n; 628 sector_num += n; 629 buf += n * 512; 630 } 631 qemu_co_mutex_unlock(&s->lock); 632 633 if (qiov->niov > 1) { 634 qemu_vfree(orig_buf); 635 } 636 g_free(cluster_data); 637 638 return ret; 639 } 640 641 static void qcow_close(BlockDriverState *bs) 642 { 643 BDRVQcowState *s = bs->opaque; 644 645 g_free(s->l1_table); 646 g_free(s->l2_cache); 647 g_free(s->cluster_cache); 648 g_free(s->cluster_data); 649 650 migrate_del_blocker(s->migration_blocker); 651 error_free(s->migration_blocker); 652 } 653 654 static int qcow_create(const char *filename, QEMUOptionParameter *options) 655 { 656 int header_size, backing_filename_len, l1_size, shift, i; 657 QCowHeader header; 658 uint8_t *tmp; 659 int64_t total_size = 0; 660 const char *backing_file = NULL; 661 int flags = 0; 662 int ret; 663 BlockDriverState *qcow_bs; 664 665 /* Read out options */ 666 while (options && options->name) { 667 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 668 total_size = options->value.n / 512; 669 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 670 backing_file = options->value.s; 671 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 672 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 673 } 674 options++; 675 } 676 677 ret = bdrv_create_file(filename, options); 678 if (ret < 0) { 679 return ret; 680 } 681 682 ret = bdrv_file_open(&qcow_bs, filename, NULL, BDRV_O_RDWR); 683 if (ret < 0) { 684 return ret; 685 } 686 687 ret = bdrv_truncate(qcow_bs, 0); 688 if (ret < 0) { 689 goto exit; 690 } 691 692 memset(&header, 0, sizeof(header)); 693 header.magic = cpu_to_be32(QCOW_MAGIC); 694 header.version = cpu_to_be32(QCOW_VERSION); 695 header.size = cpu_to_be64(total_size * 512); 696 header_size = sizeof(header); 697 backing_filename_len = 0; 698 if (backing_file) { 699 if (strcmp(backing_file, "fat:")) { 700 header.backing_file_offset = cpu_to_be64(header_size); 701 backing_filename_len = strlen(backing_file); 702 header.backing_file_size = cpu_to_be32(backing_filename_len); 703 header_size += backing_filename_len; 704 } else { 705 /* special backing file for vvfat */ 706 backing_file = NULL; 707 } 708 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 709 unmodifyed sectors */ 710 header.l2_bits = 12; /* 32 KB L2 tables */ 711 } else { 712 header.cluster_bits = 12; /* 4 KB clusters */ 713 header.l2_bits = 9; /* 4 KB L2 tables */ 714 } 715 header_size = (header_size + 7) & ~7; 716 shift = header.cluster_bits + header.l2_bits; 717 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 718 719 header.l1_table_offset = cpu_to_be64(header_size); 720 if (flags & BLOCK_FLAG_ENCRYPT) { 721 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 722 } else { 723 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 724 } 725 726 /* write all the data */ 727 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 728 if (ret != sizeof(header)) { 729 goto exit; 730 } 731 732 if (backing_file) { 733 ret = bdrv_pwrite(qcow_bs, sizeof(header), 734 backing_file, backing_filename_len); 735 if (ret != backing_filename_len) { 736 goto exit; 737 } 738 } 739 740 tmp = g_malloc0(BDRV_SECTOR_SIZE); 741 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 742 BDRV_SECTOR_SIZE); i++) { 743 ret = bdrv_pwrite(qcow_bs, header_size + 744 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 745 if (ret != BDRV_SECTOR_SIZE) { 746 g_free(tmp); 747 goto exit; 748 } 749 } 750 751 g_free(tmp); 752 ret = 0; 753 exit: 754 bdrv_delete(qcow_bs); 755 return ret; 756 } 757 758 static int qcow_make_empty(BlockDriverState *bs) 759 { 760 BDRVQcowState *s = bs->opaque; 761 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 762 int ret; 763 764 memset(s->l1_table, 0, l1_length); 765 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 766 l1_length) < 0) 767 return -1; 768 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 769 if (ret < 0) 770 return ret; 771 772 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 773 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 774 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 775 776 return 0; 777 } 778 779 /* XXX: put compressed sectors first, then all the cluster aligned 780 tables to avoid losing bytes in alignment */ 781 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 782 const uint8_t *buf, int nb_sectors) 783 { 784 BDRVQcowState *s = bs->opaque; 785 z_stream strm; 786 int ret, out_len; 787 uint8_t *out_buf; 788 uint64_t cluster_offset; 789 790 if (nb_sectors != s->cluster_sectors) { 791 ret = -EINVAL; 792 793 /* Zero-pad last write if image size is not cluster aligned */ 794 if (sector_num + nb_sectors == bs->total_sectors && 795 nb_sectors < s->cluster_sectors) { 796 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 797 memset(pad_buf, 0, s->cluster_size); 798 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 799 ret = qcow_write_compressed(bs, sector_num, 800 pad_buf, s->cluster_sectors); 801 qemu_vfree(pad_buf); 802 } 803 return ret; 804 } 805 806 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 807 808 /* best compression, small window, no zlib header */ 809 memset(&strm, 0, sizeof(strm)); 810 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 811 Z_DEFLATED, -12, 812 9, Z_DEFAULT_STRATEGY); 813 if (ret != 0) { 814 ret = -EINVAL; 815 goto fail; 816 } 817 818 strm.avail_in = s->cluster_size; 819 strm.next_in = (uint8_t *)buf; 820 strm.avail_out = s->cluster_size; 821 strm.next_out = out_buf; 822 823 ret = deflate(&strm, Z_FINISH); 824 if (ret != Z_STREAM_END && ret != Z_OK) { 825 deflateEnd(&strm); 826 ret = -EINVAL; 827 goto fail; 828 } 829 out_len = strm.next_out - out_buf; 830 831 deflateEnd(&strm); 832 833 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 834 /* could not compress: write normal cluster */ 835 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 836 if (ret < 0) { 837 goto fail; 838 } 839 } else { 840 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 841 out_len, 0, 0); 842 if (cluster_offset == 0) { 843 ret = -EIO; 844 goto fail; 845 } 846 847 cluster_offset &= s->cluster_offset_mask; 848 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 849 if (ret < 0) { 850 goto fail; 851 } 852 } 853 854 ret = 0; 855 fail: 856 g_free(out_buf); 857 return ret; 858 } 859 860 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 861 { 862 BDRVQcowState *s = bs->opaque; 863 bdi->cluster_size = s->cluster_size; 864 return 0; 865 } 866 867 868 static QEMUOptionParameter qcow_create_options[] = { 869 { 870 .name = BLOCK_OPT_SIZE, 871 .type = OPT_SIZE, 872 .help = "Virtual disk size" 873 }, 874 { 875 .name = BLOCK_OPT_BACKING_FILE, 876 .type = OPT_STRING, 877 .help = "File name of a base image" 878 }, 879 { 880 .name = BLOCK_OPT_ENCRYPT, 881 .type = OPT_FLAG, 882 .help = "Encrypt the image" 883 }, 884 { NULL } 885 }; 886 887 static BlockDriver bdrv_qcow = { 888 .format_name = "qcow", 889 .instance_size = sizeof(BDRVQcowState), 890 .bdrv_probe = qcow_probe, 891 .bdrv_open = qcow_open, 892 .bdrv_close = qcow_close, 893 .bdrv_reopen_prepare = qcow_reopen_prepare, 894 .bdrv_create = qcow_create, 895 896 .bdrv_co_readv = qcow_co_readv, 897 .bdrv_co_writev = qcow_co_writev, 898 .bdrv_co_is_allocated = qcow_co_is_allocated, 899 900 .bdrv_set_key = qcow_set_key, 901 .bdrv_make_empty = qcow_make_empty, 902 .bdrv_write_compressed = qcow_write_compressed, 903 .bdrv_get_info = qcow_get_info, 904 905 .create_options = qcow_create_options, 906 }; 907 908 static void bdrv_qcow_init(void) 909 { 910 bdrv_register(&bdrv_qcow); 911 } 912 913 block_init(bdrv_qcow_init); 914