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 30 /**************************************************************/ 31 /* QEMU COW block driver with compression and encryption support */ 32 33 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 34 #define QCOW_VERSION 1 35 36 #define QCOW_CRYPT_NONE 0 37 #define QCOW_CRYPT_AES 1 38 39 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 40 41 typedef struct QCowHeader { 42 uint32_t magic; 43 uint32_t version; 44 uint64_t backing_file_offset; 45 uint32_t backing_file_size; 46 uint32_t mtime; 47 uint64_t size; /* in bytes */ 48 uint8_t cluster_bits; 49 uint8_t l2_bits; 50 uint32_t crypt_method; 51 uint64_t l1_table_offset; 52 } QCowHeader; 53 54 #define L2_CACHE_SIZE 16 55 56 typedef struct BDRVQcowState { 57 int cluster_bits; 58 int cluster_size; 59 int cluster_sectors; 60 int l2_bits; 61 int l2_size; 62 int l1_size; 63 uint64_t cluster_offset_mask; 64 uint64_t l1_table_offset; 65 uint64_t *l1_table; 66 uint64_t *l2_cache; 67 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 68 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 69 uint8_t *cluster_cache; 70 uint8_t *cluster_data; 71 uint64_t cluster_cache_offset; 72 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 73 uint32_t crypt_method_header; 74 AES_KEY aes_encrypt_key; 75 AES_KEY aes_decrypt_key; 76 CoMutex lock; 77 } BDRVQcowState; 78 79 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 80 81 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 82 { 83 const QCowHeader *cow_header = (const void *)buf; 84 85 if (buf_size >= sizeof(QCowHeader) && 86 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 87 be32_to_cpu(cow_header->version) == QCOW_VERSION) 88 return 100; 89 else 90 return 0; 91 } 92 93 static int qcow_open(BlockDriverState *bs, int flags) 94 { 95 BDRVQcowState *s = bs->opaque; 96 int len, i, shift; 97 QCowHeader header; 98 99 if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header)) 100 goto fail; 101 be32_to_cpus(&header.magic); 102 be32_to_cpus(&header.version); 103 be64_to_cpus(&header.backing_file_offset); 104 be32_to_cpus(&header.backing_file_size); 105 be32_to_cpus(&header.mtime); 106 be64_to_cpus(&header.size); 107 be32_to_cpus(&header.crypt_method); 108 be64_to_cpus(&header.l1_table_offset); 109 110 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION) 111 goto fail; 112 if (header.size <= 1 || header.cluster_bits < 9) 113 goto fail; 114 if (header.crypt_method > QCOW_CRYPT_AES) 115 goto fail; 116 s->crypt_method_header = header.crypt_method; 117 if (s->crypt_method_header) 118 bs->encrypted = 1; 119 s->cluster_bits = header.cluster_bits; 120 s->cluster_size = 1 << s->cluster_bits; 121 s->cluster_sectors = 1 << (s->cluster_bits - 9); 122 s->l2_bits = header.l2_bits; 123 s->l2_size = 1 << s->l2_bits; 124 bs->total_sectors = header.size / 512; 125 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 126 127 /* read the level 1 table */ 128 shift = s->cluster_bits + s->l2_bits; 129 s->l1_size = (header.size + (1LL << shift) - 1) >> shift; 130 131 s->l1_table_offset = header.l1_table_offset; 132 s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); 133 if (!s->l1_table) 134 goto fail; 135 if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != 136 s->l1_size * sizeof(uint64_t)) 137 goto fail; 138 for(i = 0;i < s->l1_size; i++) { 139 be64_to_cpus(&s->l1_table[i]); 140 } 141 /* alloc L2 cache */ 142 s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 143 if (!s->l2_cache) 144 goto fail; 145 s->cluster_cache = g_malloc(s->cluster_size); 146 if (!s->cluster_cache) 147 goto fail; 148 s->cluster_data = g_malloc(s->cluster_size); 149 if (!s->cluster_data) 150 goto fail; 151 s->cluster_cache_offset = -1; 152 153 /* read the backing file name */ 154 if (header.backing_file_offset != 0) { 155 len = header.backing_file_size; 156 if (len > 1023) 157 len = 1023; 158 if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len) 159 goto fail; 160 bs->backing_file[len] = '\0'; 161 } 162 163 qemu_co_mutex_init(&s->lock); 164 return 0; 165 166 fail: 167 g_free(s->l1_table); 168 g_free(s->l2_cache); 169 g_free(s->cluster_cache); 170 g_free(s->cluster_data); 171 return -1; 172 } 173 174 static int qcow_set_key(BlockDriverState *bs, const char *key) 175 { 176 BDRVQcowState *s = bs->opaque; 177 uint8_t keybuf[16]; 178 int len, i; 179 180 memset(keybuf, 0, 16); 181 len = strlen(key); 182 if (len > 16) 183 len = 16; 184 /* XXX: we could compress the chars to 7 bits to increase 185 entropy */ 186 for(i = 0;i < len;i++) { 187 keybuf[i] = key[i]; 188 } 189 s->crypt_method = s->crypt_method_header; 190 191 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 192 return -1; 193 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 194 return -1; 195 return 0; 196 } 197 198 /* The crypt function is compatible with the linux cryptoloop 199 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 200 supported */ 201 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 202 uint8_t *out_buf, const uint8_t *in_buf, 203 int nb_sectors, int enc, 204 const AES_KEY *key) 205 { 206 union { 207 uint64_t ll[2]; 208 uint8_t b[16]; 209 } ivec; 210 int i; 211 212 for(i = 0; i < nb_sectors; i++) { 213 ivec.ll[0] = cpu_to_le64(sector_num); 214 ivec.ll[1] = 0; 215 AES_cbc_encrypt(in_buf, out_buf, 512, key, 216 ivec.b, enc); 217 sector_num++; 218 in_buf += 512; 219 out_buf += 512; 220 } 221 } 222 223 /* 'allocate' is: 224 * 225 * 0 to not allocate. 226 * 227 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 228 * 'n_end') 229 * 230 * 2 to allocate a compressed cluster of size 231 * 'compressed_size'. 'compressed_size' must be > 0 and < 232 * cluster_size 233 * 234 * return 0 if not allocated. 235 */ 236 static uint64_t get_cluster_offset(BlockDriverState *bs, 237 uint64_t offset, int allocate, 238 int compressed_size, 239 int n_start, int n_end) 240 { 241 BDRVQcowState *s = bs->opaque; 242 int min_index, i, j, l1_index, l2_index; 243 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 244 uint32_t min_count; 245 int new_l2_table; 246 247 l1_index = offset >> (s->l2_bits + s->cluster_bits); 248 l2_offset = s->l1_table[l1_index]; 249 new_l2_table = 0; 250 if (!l2_offset) { 251 if (!allocate) 252 return 0; 253 /* allocate a new l2 entry */ 254 l2_offset = bdrv_getlength(bs->file); 255 /* round to cluster size */ 256 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 257 /* update the L1 entry */ 258 s->l1_table[l1_index] = l2_offset; 259 tmp = cpu_to_be64(l2_offset); 260 if (bdrv_pwrite_sync(bs->file, 261 s->l1_table_offset + l1_index * sizeof(tmp), 262 &tmp, sizeof(tmp)) < 0) 263 return 0; 264 new_l2_table = 1; 265 } 266 for(i = 0; i < L2_CACHE_SIZE; i++) { 267 if (l2_offset == s->l2_cache_offsets[i]) { 268 /* increment the hit count */ 269 if (++s->l2_cache_counts[i] == 0xffffffff) { 270 for(j = 0; j < L2_CACHE_SIZE; j++) { 271 s->l2_cache_counts[j] >>= 1; 272 } 273 } 274 l2_table = s->l2_cache + (i << s->l2_bits); 275 goto found; 276 } 277 } 278 /* not found: load a new entry in the least used one */ 279 min_index = 0; 280 min_count = 0xffffffff; 281 for(i = 0; i < L2_CACHE_SIZE; i++) { 282 if (s->l2_cache_counts[i] < min_count) { 283 min_count = s->l2_cache_counts[i]; 284 min_index = i; 285 } 286 } 287 l2_table = s->l2_cache + (min_index << s->l2_bits); 288 if (new_l2_table) { 289 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 290 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 291 s->l2_size * sizeof(uint64_t)) < 0) 292 return 0; 293 } else { 294 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 295 s->l2_size * sizeof(uint64_t)) 296 return 0; 297 } 298 s->l2_cache_offsets[min_index] = l2_offset; 299 s->l2_cache_counts[min_index] = 1; 300 found: 301 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 302 cluster_offset = be64_to_cpu(l2_table[l2_index]); 303 if (!cluster_offset || 304 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 305 if (!allocate) 306 return 0; 307 /* allocate a new cluster */ 308 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 309 (n_end - n_start) < s->cluster_sectors) { 310 /* if the cluster is already compressed, we must 311 decompress it in the case it is not completely 312 overwritten */ 313 if (decompress_cluster(bs, cluster_offset) < 0) 314 return 0; 315 cluster_offset = bdrv_getlength(bs->file); 316 cluster_offset = (cluster_offset + s->cluster_size - 1) & 317 ~(s->cluster_size - 1); 318 /* write the cluster content */ 319 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 320 s->cluster_size) 321 return -1; 322 } else { 323 cluster_offset = bdrv_getlength(bs->file); 324 if (allocate == 1) { 325 /* round to cluster size */ 326 cluster_offset = (cluster_offset + s->cluster_size - 1) & 327 ~(s->cluster_size - 1); 328 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 329 /* if encrypted, we must initialize the cluster 330 content which won't be written */ 331 if (s->crypt_method && 332 (n_end - n_start) < s->cluster_sectors) { 333 uint64_t start_sect; 334 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 335 memset(s->cluster_data + 512, 0x00, 512); 336 for(i = 0; i < s->cluster_sectors; i++) { 337 if (i < n_start || i >= n_end) { 338 encrypt_sectors(s, start_sect + i, 339 s->cluster_data, 340 s->cluster_data + 512, 1, 1, 341 &s->aes_encrypt_key); 342 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 343 s->cluster_data, 512) != 512) 344 return -1; 345 } 346 } 347 } 348 } else if (allocate == 2) { 349 cluster_offset |= QCOW_OFLAG_COMPRESSED | 350 (uint64_t)compressed_size << (63 - s->cluster_bits); 351 } 352 } 353 /* update L2 table */ 354 tmp = cpu_to_be64(cluster_offset); 355 l2_table[l2_index] = tmp; 356 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 357 &tmp, sizeof(tmp)) < 0) 358 return 0; 359 } 360 return cluster_offset; 361 } 362 363 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, 364 int nb_sectors, int *pnum) 365 { 366 BDRVQcowState *s = bs->opaque; 367 int index_in_cluster, n; 368 uint64_t cluster_offset; 369 370 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 371 index_in_cluster = sector_num & (s->cluster_sectors - 1); 372 n = s->cluster_sectors - index_in_cluster; 373 if (n > nb_sectors) 374 n = nb_sectors; 375 *pnum = n; 376 return (cluster_offset != 0); 377 } 378 379 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 380 const uint8_t *buf, int buf_size) 381 { 382 z_stream strm1, *strm = &strm1; 383 int ret, out_len; 384 385 memset(strm, 0, sizeof(*strm)); 386 387 strm->next_in = (uint8_t *)buf; 388 strm->avail_in = buf_size; 389 strm->next_out = out_buf; 390 strm->avail_out = out_buf_size; 391 392 ret = inflateInit2(strm, -12); 393 if (ret != Z_OK) 394 return -1; 395 ret = inflate(strm, Z_FINISH); 396 out_len = strm->next_out - out_buf; 397 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 398 out_len != out_buf_size) { 399 inflateEnd(strm); 400 return -1; 401 } 402 inflateEnd(strm); 403 return 0; 404 } 405 406 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 407 { 408 BDRVQcowState *s = bs->opaque; 409 int ret, csize; 410 uint64_t coffset; 411 412 coffset = cluster_offset & s->cluster_offset_mask; 413 if (s->cluster_cache_offset != coffset) { 414 csize = cluster_offset >> (63 - s->cluster_bits); 415 csize &= (s->cluster_size - 1); 416 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 417 if (ret != csize) 418 return -1; 419 if (decompress_buffer(s->cluster_cache, s->cluster_size, 420 s->cluster_data, csize) < 0) { 421 return -1; 422 } 423 s->cluster_cache_offset = coffset; 424 } 425 return 0; 426 } 427 428 static int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 429 int nb_sectors, QEMUIOVector *qiov) 430 { 431 BDRVQcowState *s = bs->opaque; 432 int index_in_cluster; 433 int ret = 0, n; 434 uint64_t cluster_offset; 435 struct iovec hd_iov; 436 QEMUIOVector hd_qiov; 437 uint8_t *buf; 438 void *orig_buf; 439 440 if (qiov->niov > 1) { 441 buf = orig_buf = qemu_blockalign(bs, qiov->size); 442 } else { 443 orig_buf = NULL; 444 buf = (uint8_t *)qiov->iov->iov_base; 445 } 446 447 qemu_co_mutex_lock(&s->lock); 448 449 while (nb_sectors != 0) { 450 /* prepare next request */ 451 cluster_offset = get_cluster_offset(bs, sector_num << 9, 452 0, 0, 0, 0); 453 index_in_cluster = sector_num & (s->cluster_sectors - 1); 454 n = s->cluster_sectors - index_in_cluster; 455 if (n > nb_sectors) { 456 n = nb_sectors; 457 } 458 459 if (!cluster_offset) { 460 if (bs->backing_hd) { 461 /* read from the base image */ 462 hd_iov.iov_base = (void *)buf; 463 hd_iov.iov_len = n * 512; 464 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 465 qemu_co_mutex_unlock(&s->lock); 466 ret = bdrv_co_readv(bs->backing_hd, sector_num, 467 n, &hd_qiov); 468 qemu_co_mutex_lock(&s->lock); 469 if (ret < 0) { 470 goto fail; 471 } 472 } else { 473 /* Note: in this case, no need to wait */ 474 memset(buf, 0, 512 * n); 475 } 476 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 477 /* add AIO support for compressed blocks ? */ 478 if (decompress_cluster(bs, cluster_offset) < 0) { 479 goto fail; 480 } 481 memcpy(buf, 482 s->cluster_cache + index_in_cluster * 512, 512 * n); 483 } else { 484 if ((cluster_offset & 511) != 0) { 485 goto fail; 486 } 487 hd_iov.iov_base = (void *)buf; 488 hd_iov.iov_len = n * 512; 489 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 490 qemu_co_mutex_unlock(&s->lock); 491 ret = bdrv_co_readv(bs->file, 492 (cluster_offset >> 9) + index_in_cluster, 493 n, &hd_qiov); 494 qemu_co_mutex_lock(&s->lock); 495 if (ret < 0) { 496 break; 497 } 498 if (s->crypt_method) { 499 encrypt_sectors(s, sector_num, buf, buf, 500 n, 0, 501 &s->aes_decrypt_key); 502 } 503 } 504 ret = 0; 505 506 nb_sectors -= n; 507 sector_num += n; 508 buf += n * 512; 509 } 510 511 done: 512 qemu_co_mutex_unlock(&s->lock); 513 514 if (qiov->niov > 1) { 515 qemu_iovec_from_buffer(qiov, orig_buf, qiov->size); 516 qemu_vfree(orig_buf); 517 } 518 519 return ret; 520 521 fail: 522 ret = -EIO; 523 goto done; 524 } 525 526 static int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 527 int nb_sectors, QEMUIOVector *qiov) 528 { 529 BDRVQcowState *s = bs->opaque; 530 int index_in_cluster; 531 uint64_t cluster_offset; 532 const uint8_t *src_buf; 533 int ret = 0, n; 534 uint8_t *cluster_data = NULL; 535 struct iovec hd_iov; 536 QEMUIOVector hd_qiov; 537 uint8_t *buf; 538 void *orig_buf; 539 540 s->cluster_cache_offset = -1; /* disable compressed cache */ 541 542 if (qiov->niov > 1) { 543 buf = orig_buf = qemu_blockalign(bs, qiov->size); 544 qemu_iovec_to_buffer(qiov, buf); 545 } else { 546 orig_buf = NULL; 547 buf = (uint8_t *)qiov->iov->iov_base; 548 } 549 550 qemu_co_mutex_lock(&s->lock); 551 552 while (nb_sectors != 0) { 553 554 index_in_cluster = sector_num & (s->cluster_sectors - 1); 555 n = s->cluster_sectors - index_in_cluster; 556 if (n > nb_sectors) { 557 n = nb_sectors; 558 } 559 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 560 index_in_cluster, 561 index_in_cluster + n); 562 if (!cluster_offset || (cluster_offset & 511) != 0) { 563 ret = -EIO; 564 break; 565 } 566 if (s->crypt_method) { 567 if (!cluster_data) { 568 cluster_data = g_malloc0(s->cluster_size); 569 } 570 encrypt_sectors(s, sector_num, cluster_data, buf, 571 n, 1, &s->aes_encrypt_key); 572 src_buf = cluster_data; 573 } else { 574 src_buf = buf; 575 } 576 577 hd_iov.iov_base = (void *)src_buf; 578 hd_iov.iov_len = n * 512; 579 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 580 qemu_co_mutex_unlock(&s->lock); 581 ret = bdrv_co_writev(bs->file, 582 (cluster_offset >> 9) + index_in_cluster, 583 n, &hd_qiov); 584 qemu_co_mutex_lock(&s->lock); 585 if (ret < 0) { 586 break; 587 } 588 ret = 0; 589 590 nb_sectors -= n; 591 sector_num += n; 592 buf += n * 512; 593 } 594 qemu_co_mutex_unlock(&s->lock); 595 596 if (qiov->niov > 1) { 597 qemu_vfree(orig_buf); 598 } 599 free(cluster_data); 600 601 return ret; 602 } 603 604 static void qcow_close(BlockDriverState *bs) 605 { 606 BDRVQcowState *s = bs->opaque; 607 g_free(s->l1_table); 608 g_free(s->l2_cache); 609 g_free(s->cluster_cache); 610 g_free(s->cluster_data); 611 } 612 613 static int qcow_create(const char *filename, QEMUOptionParameter *options) 614 { 615 int fd, header_size, backing_filename_len, l1_size, i, shift; 616 QCowHeader header; 617 uint64_t tmp; 618 int64_t total_size = 0; 619 const char *backing_file = NULL; 620 int flags = 0; 621 int ret; 622 623 /* Read out options */ 624 while (options && options->name) { 625 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 626 total_size = options->value.n / 512; 627 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 628 backing_file = options->value.s; 629 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 630 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 631 } 632 options++; 633 } 634 635 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); 636 if (fd < 0) 637 return -errno; 638 memset(&header, 0, sizeof(header)); 639 header.magic = cpu_to_be32(QCOW_MAGIC); 640 header.version = cpu_to_be32(QCOW_VERSION); 641 header.size = cpu_to_be64(total_size * 512); 642 header_size = sizeof(header); 643 backing_filename_len = 0; 644 if (backing_file) { 645 if (strcmp(backing_file, "fat:")) { 646 header.backing_file_offset = cpu_to_be64(header_size); 647 backing_filename_len = strlen(backing_file); 648 header.backing_file_size = cpu_to_be32(backing_filename_len); 649 header_size += backing_filename_len; 650 } else { 651 /* special backing file for vvfat */ 652 backing_file = NULL; 653 } 654 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 655 unmodifyed sectors */ 656 header.l2_bits = 12; /* 32 KB L2 tables */ 657 } else { 658 header.cluster_bits = 12; /* 4 KB clusters */ 659 header.l2_bits = 9; /* 4 KB L2 tables */ 660 } 661 header_size = (header_size + 7) & ~7; 662 shift = header.cluster_bits + header.l2_bits; 663 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 664 665 header.l1_table_offset = cpu_to_be64(header_size); 666 if (flags & BLOCK_FLAG_ENCRYPT) { 667 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 668 } else { 669 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 670 } 671 672 /* write all the data */ 673 ret = qemu_write_full(fd, &header, sizeof(header)); 674 if (ret != sizeof(header)) { 675 ret = -errno; 676 goto exit; 677 } 678 679 if (backing_file) { 680 ret = qemu_write_full(fd, backing_file, backing_filename_len); 681 if (ret != backing_filename_len) { 682 ret = -errno; 683 goto exit; 684 } 685 686 } 687 lseek(fd, header_size, SEEK_SET); 688 tmp = 0; 689 for(i = 0;i < l1_size; i++) { 690 ret = qemu_write_full(fd, &tmp, sizeof(tmp)); 691 if (ret != sizeof(tmp)) { 692 ret = -errno; 693 goto exit; 694 } 695 } 696 697 ret = 0; 698 exit: 699 close(fd); 700 return ret; 701 } 702 703 static int qcow_make_empty(BlockDriverState *bs) 704 { 705 BDRVQcowState *s = bs->opaque; 706 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 707 int ret; 708 709 memset(s->l1_table, 0, l1_length); 710 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 711 l1_length) < 0) 712 return -1; 713 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 714 if (ret < 0) 715 return ret; 716 717 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 718 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 719 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 720 721 return 0; 722 } 723 724 /* XXX: put compressed sectors first, then all the cluster aligned 725 tables to avoid losing bytes in alignment */ 726 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 727 const uint8_t *buf, int nb_sectors) 728 { 729 BDRVQcowState *s = bs->opaque; 730 z_stream strm; 731 int ret, out_len; 732 uint8_t *out_buf; 733 uint64_t cluster_offset; 734 735 if (nb_sectors != s->cluster_sectors) 736 return -EINVAL; 737 738 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 739 if (!out_buf) 740 return -1; 741 742 /* best compression, small window, no zlib header */ 743 memset(&strm, 0, sizeof(strm)); 744 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 745 Z_DEFLATED, -12, 746 9, Z_DEFAULT_STRATEGY); 747 if (ret != 0) { 748 g_free(out_buf); 749 return -1; 750 } 751 752 strm.avail_in = s->cluster_size; 753 strm.next_in = (uint8_t *)buf; 754 strm.avail_out = s->cluster_size; 755 strm.next_out = out_buf; 756 757 ret = deflate(&strm, Z_FINISH); 758 if (ret != Z_STREAM_END && ret != Z_OK) { 759 g_free(out_buf); 760 deflateEnd(&strm); 761 return -1; 762 } 763 out_len = strm.next_out - out_buf; 764 765 deflateEnd(&strm); 766 767 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 768 /* could not compress: write normal cluster */ 769 bdrv_write(bs, sector_num, buf, s->cluster_sectors); 770 } else { 771 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 772 out_len, 0, 0); 773 cluster_offset &= s->cluster_offset_mask; 774 if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) { 775 g_free(out_buf); 776 return -1; 777 } 778 } 779 780 g_free(out_buf); 781 return 0; 782 } 783 784 static int qcow_flush(BlockDriverState *bs) 785 { 786 return bdrv_flush(bs->file); 787 } 788 789 static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs, 790 BlockDriverCompletionFunc *cb, void *opaque) 791 { 792 return bdrv_aio_flush(bs->file, cb, opaque); 793 } 794 795 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 796 { 797 BDRVQcowState *s = bs->opaque; 798 bdi->cluster_size = s->cluster_size; 799 return 0; 800 } 801 802 803 static QEMUOptionParameter qcow_create_options[] = { 804 { 805 .name = BLOCK_OPT_SIZE, 806 .type = OPT_SIZE, 807 .help = "Virtual disk size" 808 }, 809 { 810 .name = BLOCK_OPT_BACKING_FILE, 811 .type = OPT_STRING, 812 .help = "File name of a base image" 813 }, 814 { 815 .name = BLOCK_OPT_ENCRYPT, 816 .type = OPT_FLAG, 817 .help = "Encrypt the image" 818 }, 819 { NULL } 820 }; 821 822 static BlockDriver bdrv_qcow = { 823 .format_name = "qcow", 824 .instance_size = sizeof(BDRVQcowState), 825 .bdrv_probe = qcow_probe, 826 .bdrv_open = qcow_open, 827 .bdrv_close = qcow_close, 828 .bdrv_create = qcow_create, 829 .bdrv_flush = qcow_flush, 830 .bdrv_is_allocated = qcow_is_allocated, 831 .bdrv_set_key = qcow_set_key, 832 .bdrv_make_empty = qcow_make_empty, 833 .bdrv_co_readv = qcow_co_readv, 834 .bdrv_co_writev = qcow_co_writev, 835 .bdrv_aio_flush = qcow_aio_flush, 836 .bdrv_write_compressed = qcow_write_compressed, 837 .bdrv_get_info = qcow_get_info, 838 839 .create_options = qcow_create_options, 840 }; 841 842 static void bdrv_qcow_init(void) 843 { 844 bdrv_register(&bdrv_qcow); 845 } 846 847 block_init(bdrv_qcow_init); 848