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 Error **errp) 97 { 98 BDRVQcowState *s = bs->opaque; 99 int len, i, shift, ret; 100 QCowHeader header; 101 102 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 103 if (ret < 0) { 104 goto fail; 105 } 106 be32_to_cpus(&header.magic); 107 be32_to_cpus(&header.version); 108 be64_to_cpus(&header.backing_file_offset); 109 be32_to_cpus(&header.backing_file_size); 110 be32_to_cpus(&header.mtime); 111 be64_to_cpus(&header.size); 112 be32_to_cpus(&header.crypt_method); 113 be64_to_cpus(&header.l1_table_offset); 114 115 if (header.magic != QCOW_MAGIC) { 116 ret = -EMEDIUMTYPE; 117 goto fail; 118 } 119 if (header.version != QCOW_VERSION) { 120 char version[64]; 121 snprintf(version, sizeof(version), "QCOW version %d", header.version); 122 qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 123 bs->device_name, "qcow", version); 124 ret = -ENOTSUP; 125 goto fail; 126 } 127 128 if (header.size <= 1 || header.cluster_bits < 9) { 129 ret = -EINVAL; 130 goto fail; 131 } 132 if (header.crypt_method > QCOW_CRYPT_AES) { 133 ret = -EINVAL; 134 goto fail; 135 } 136 s->crypt_method_header = header.crypt_method; 137 if (s->crypt_method_header) { 138 bs->encrypted = 1; 139 } 140 s->cluster_bits = header.cluster_bits; 141 s->cluster_size = 1 << s->cluster_bits; 142 s->cluster_sectors = 1 << (s->cluster_bits - 9); 143 s->l2_bits = header.l2_bits; 144 s->l2_size = 1 << s->l2_bits; 145 bs->total_sectors = header.size / 512; 146 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 147 148 /* read the level 1 table */ 149 shift = s->cluster_bits + s->l2_bits; 150 s->l1_size = (header.size + (1LL << shift) - 1) >> shift; 151 152 s->l1_table_offset = header.l1_table_offset; 153 s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); 154 155 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 156 s->l1_size * sizeof(uint64_t)); 157 if (ret < 0) { 158 goto fail; 159 } 160 161 for(i = 0;i < s->l1_size; i++) { 162 be64_to_cpus(&s->l1_table[i]); 163 } 164 /* alloc L2 cache */ 165 s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 166 s->cluster_cache = g_malloc(s->cluster_size); 167 s->cluster_data = g_malloc(s->cluster_size); 168 s->cluster_cache_offset = -1; 169 170 /* read the backing file name */ 171 if (header.backing_file_offset != 0) { 172 len = header.backing_file_size; 173 if (len > 1023) { 174 len = 1023; 175 } 176 ret = bdrv_pread(bs->file, header.backing_file_offset, 177 bs->backing_file, len); 178 if (ret < 0) { 179 goto fail; 180 } 181 bs->backing_file[len] = '\0'; 182 } 183 184 /* Disable migration when qcow images are used */ 185 error_set(&s->migration_blocker, 186 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 187 "qcow", bs->device_name, "live migration"); 188 migrate_add_blocker(s->migration_blocker); 189 190 qemu_co_mutex_init(&s->lock); 191 return 0; 192 193 fail: 194 g_free(s->l1_table); 195 g_free(s->l2_cache); 196 g_free(s->cluster_cache); 197 g_free(s->cluster_data); 198 return ret; 199 } 200 201 202 /* We have nothing to do for QCOW reopen, stubs just return 203 * success */ 204 static int qcow_reopen_prepare(BDRVReopenState *state, 205 BlockReopenQueue *queue, Error **errp) 206 { 207 return 0; 208 } 209 210 static int qcow_set_key(BlockDriverState *bs, const char *key) 211 { 212 BDRVQcowState *s = bs->opaque; 213 uint8_t keybuf[16]; 214 int len, i; 215 216 memset(keybuf, 0, 16); 217 len = strlen(key); 218 if (len > 16) 219 len = 16; 220 /* XXX: we could compress the chars to 7 bits to increase 221 entropy */ 222 for(i = 0;i < len;i++) { 223 keybuf[i] = key[i]; 224 } 225 s->crypt_method = s->crypt_method_header; 226 227 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 228 return -1; 229 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 230 return -1; 231 return 0; 232 } 233 234 /* The crypt function is compatible with the linux cryptoloop 235 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 236 supported */ 237 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 238 uint8_t *out_buf, const uint8_t *in_buf, 239 int nb_sectors, int enc, 240 const AES_KEY *key) 241 { 242 union { 243 uint64_t ll[2]; 244 uint8_t b[16]; 245 } ivec; 246 int i; 247 248 for(i = 0; i < nb_sectors; i++) { 249 ivec.ll[0] = cpu_to_le64(sector_num); 250 ivec.ll[1] = 0; 251 AES_cbc_encrypt(in_buf, out_buf, 512, key, 252 ivec.b, enc); 253 sector_num++; 254 in_buf += 512; 255 out_buf += 512; 256 } 257 } 258 259 /* 'allocate' is: 260 * 261 * 0 to not allocate. 262 * 263 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 264 * 'n_end') 265 * 266 * 2 to allocate a compressed cluster of size 267 * 'compressed_size'. 'compressed_size' must be > 0 and < 268 * cluster_size 269 * 270 * return 0 if not allocated. 271 */ 272 static uint64_t get_cluster_offset(BlockDriverState *bs, 273 uint64_t offset, int allocate, 274 int compressed_size, 275 int n_start, int n_end) 276 { 277 BDRVQcowState *s = bs->opaque; 278 int min_index, i, j, l1_index, l2_index; 279 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 280 uint32_t min_count; 281 int new_l2_table; 282 283 l1_index = offset >> (s->l2_bits + s->cluster_bits); 284 l2_offset = s->l1_table[l1_index]; 285 new_l2_table = 0; 286 if (!l2_offset) { 287 if (!allocate) 288 return 0; 289 /* allocate a new l2 entry */ 290 l2_offset = bdrv_getlength(bs->file); 291 /* round to cluster size */ 292 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 293 /* update the L1 entry */ 294 s->l1_table[l1_index] = l2_offset; 295 tmp = cpu_to_be64(l2_offset); 296 if (bdrv_pwrite_sync(bs->file, 297 s->l1_table_offset + l1_index * sizeof(tmp), 298 &tmp, sizeof(tmp)) < 0) 299 return 0; 300 new_l2_table = 1; 301 } 302 for(i = 0; i < L2_CACHE_SIZE; i++) { 303 if (l2_offset == s->l2_cache_offsets[i]) { 304 /* increment the hit count */ 305 if (++s->l2_cache_counts[i] == 0xffffffff) { 306 for(j = 0; j < L2_CACHE_SIZE; j++) { 307 s->l2_cache_counts[j] >>= 1; 308 } 309 } 310 l2_table = s->l2_cache + (i << s->l2_bits); 311 goto found; 312 } 313 } 314 /* not found: load a new entry in the least used one */ 315 min_index = 0; 316 min_count = 0xffffffff; 317 for(i = 0; i < L2_CACHE_SIZE; i++) { 318 if (s->l2_cache_counts[i] < min_count) { 319 min_count = s->l2_cache_counts[i]; 320 min_index = i; 321 } 322 } 323 l2_table = s->l2_cache + (min_index << s->l2_bits); 324 if (new_l2_table) { 325 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 326 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 327 s->l2_size * sizeof(uint64_t)) < 0) 328 return 0; 329 } else { 330 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 331 s->l2_size * sizeof(uint64_t)) 332 return 0; 333 } 334 s->l2_cache_offsets[min_index] = l2_offset; 335 s->l2_cache_counts[min_index] = 1; 336 found: 337 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 338 cluster_offset = be64_to_cpu(l2_table[l2_index]); 339 if (!cluster_offset || 340 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 341 if (!allocate) 342 return 0; 343 /* allocate a new cluster */ 344 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 345 (n_end - n_start) < s->cluster_sectors) { 346 /* if the cluster is already compressed, we must 347 decompress it in the case it is not completely 348 overwritten */ 349 if (decompress_cluster(bs, cluster_offset) < 0) 350 return 0; 351 cluster_offset = bdrv_getlength(bs->file); 352 cluster_offset = (cluster_offset + s->cluster_size - 1) & 353 ~(s->cluster_size - 1); 354 /* write the cluster content */ 355 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 356 s->cluster_size) 357 return -1; 358 } else { 359 cluster_offset = bdrv_getlength(bs->file); 360 if (allocate == 1) { 361 /* round to cluster size */ 362 cluster_offset = (cluster_offset + s->cluster_size - 1) & 363 ~(s->cluster_size - 1); 364 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 365 /* if encrypted, we must initialize the cluster 366 content which won't be written */ 367 if (s->crypt_method && 368 (n_end - n_start) < s->cluster_sectors) { 369 uint64_t start_sect; 370 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 371 memset(s->cluster_data + 512, 0x00, 512); 372 for(i = 0; i < s->cluster_sectors; i++) { 373 if (i < n_start || i >= n_end) { 374 encrypt_sectors(s, start_sect + i, 375 s->cluster_data, 376 s->cluster_data + 512, 1, 1, 377 &s->aes_encrypt_key); 378 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 379 s->cluster_data, 512) != 512) 380 return -1; 381 } 382 } 383 } 384 } else if (allocate == 2) { 385 cluster_offset |= QCOW_OFLAG_COMPRESSED | 386 (uint64_t)compressed_size << (63 - s->cluster_bits); 387 } 388 } 389 /* update L2 table */ 390 tmp = cpu_to_be64(cluster_offset); 391 l2_table[l2_index] = tmp; 392 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 393 &tmp, sizeof(tmp)) < 0) 394 return 0; 395 } 396 return cluster_offset; 397 } 398 399 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 400 int64_t sector_num, int nb_sectors, int *pnum) 401 { 402 BDRVQcowState *s = bs->opaque; 403 int index_in_cluster, n; 404 uint64_t cluster_offset; 405 406 qemu_co_mutex_lock(&s->lock); 407 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 408 qemu_co_mutex_unlock(&s->lock); 409 index_in_cluster = sector_num & (s->cluster_sectors - 1); 410 n = s->cluster_sectors - index_in_cluster; 411 if (n > nb_sectors) 412 n = nb_sectors; 413 *pnum = n; 414 if (!cluster_offset) { 415 return 0; 416 } 417 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) { 418 return BDRV_BLOCK_DATA; 419 } 420 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 421 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 422 } 423 424 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 425 const uint8_t *buf, int buf_size) 426 { 427 z_stream strm1, *strm = &strm1; 428 int ret, out_len; 429 430 memset(strm, 0, sizeof(*strm)); 431 432 strm->next_in = (uint8_t *)buf; 433 strm->avail_in = buf_size; 434 strm->next_out = out_buf; 435 strm->avail_out = out_buf_size; 436 437 ret = inflateInit2(strm, -12); 438 if (ret != Z_OK) 439 return -1; 440 ret = inflate(strm, Z_FINISH); 441 out_len = strm->next_out - out_buf; 442 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 443 out_len != out_buf_size) { 444 inflateEnd(strm); 445 return -1; 446 } 447 inflateEnd(strm); 448 return 0; 449 } 450 451 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 452 { 453 BDRVQcowState *s = bs->opaque; 454 int ret, csize; 455 uint64_t coffset; 456 457 coffset = cluster_offset & s->cluster_offset_mask; 458 if (s->cluster_cache_offset != coffset) { 459 csize = cluster_offset >> (63 - s->cluster_bits); 460 csize &= (s->cluster_size - 1); 461 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 462 if (ret != csize) 463 return -1; 464 if (decompress_buffer(s->cluster_cache, s->cluster_size, 465 s->cluster_data, csize) < 0) { 466 return -1; 467 } 468 s->cluster_cache_offset = coffset; 469 } 470 return 0; 471 } 472 473 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 474 int nb_sectors, QEMUIOVector *qiov) 475 { 476 BDRVQcowState *s = bs->opaque; 477 int index_in_cluster; 478 int ret = 0, n; 479 uint64_t cluster_offset; 480 struct iovec hd_iov; 481 QEMUIOVector hd_qiov; 482 uint8_t *buf; 483 void *orig_buf; 484 485 if (qiov->niov > 1) { 486 buf = orig_buf = qemu_blockalign(bs, qiov->size); 487 } else { 488 orig_buf = NULL; 489 buf = (uint8_t *)qiov->iov->iov_base; 490 } 491 492 qemu_co_mutex_lock(&s->lock); 493 494 while (nb_sectors != 0) { 495 /* prepare next request */ 496 cluster_offset = get_cluster_offset(bs, sector_num << 9, 497 0, 0, 0, 0); 498 index_in_cluster = sector_num & (s->cluster_sectors - 1); 499 n = s->cluster_sectors - index_in_cluster; 500 if (n > nb_sectors) { 501 n = nb_sectors; 502 } 503 504 if (!cluster_offset) { 505 if (bs->backing_hd) { 506 /* read from the base image */ 507 hd_iov.iov_base = (void *)buf; 508 hd_iov.iov_len = n * 512; 509 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 510 qemu_co_mutex_unlock(&s->lock); 511 ret = bdrv_co_readv(bs->backing_hd, sector_num, 512 n, &hd_qiov); 513 qemu_co_mutex_lock(&s->lock); 514 if (ret < 0) { 515 goto fail; 516 } 517 } else { 518 /* Note: in this case, no need to wait */ 519 memset(buf, 0, 512 * n); 520 } 521 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 522 /* add AIO support for compressed blocks ? */ 523 if (decompress_cluster(bs, cluster_offset) < 0) { 524 goto fail; 525 } 526 memcpy(buf, 527 s->cluster_cache + index_in_cluster * 512, 512 * n); 528 } else { 529 if ((cluster_offset & 511) != 0) { 530 goto fail; 531 } 532 hd_iov.iov_base = (void *)buf; 533 hd_iov.iov_len = n * 512; 534 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 535 qemu_co_mutex_unlock(&s->lock); 536 ret = bdrv_co_readv(bs->file, 537 (cluster_offset >> 9) + index_in_cluster, 538 n, &hd_qiov); 539 qemu_co_mutex_lock(&s->lock); 540 if (ret < 0) { 541 break; 542 } 543 if (s->crypt_method) { 544 encrypt_sectors(s, sector_num, buf, buf, 545 n, 0, 546 &s->aes_decrypt_key); 547 } 548 } 549 ret = 0; 550 551 nb_sectors -= n; 552 sector_num += n; 553 buf += n * 512; 554 } 555 556 done: 557 qemu_co_mutex_unlock(&s->lock); 558 559 if (qiov->niov > 1) { 560 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 561 qemu_vfree(orig_buf); 562 } 563 564 return ret; 565 566 fail: 567 ret = -EIO; 568 goto done; 569 } 570 571 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 572 int nb_sectors, QEMUIOVector *qiov) 573 { 574 BDRVQcowState *s = bs->opaque; 575 int index_in_cluster; 576 uint64_t cluster_offset; 577 const uint8_t *src_buf; 578 int ret = 0, n; 579 uint8_t *cluster_data = NULL; 580 struct iovec hd_iov; 581 QEMUIOVector hd_qiov; 582 uint8_t *buf; 583 void *orig_buf; 584 585 s->cluster_cache_offset = -1; /* disable compressed cache */ 586 587 if (qiov->niov > 1) { 588 buf = orig_buf = qemu_blockalign(bs, qiov->size); 589 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 590 } else { 591 orig_buf = NULL; 592 buf = (uint8_t *)qiov->iov->iov_base; 593 } 594 595 qemu_co_mutex_lock(&s->lock); 596 597 while (nb_sectors != 0) { 598 599 index_in_cluster = sector_num & (s->cluster_sectors - 1); 600 n = s->cluster_sectors - index_in_cluster; 601 if (n > nb_sectors) { 602 n = nb_sectors; 603 } 604 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 605 index_in_cluster, 606 index_in_cluster + n); 607 if (!cluster_offset || (cluster_offset & 511) != 0) { 608 ret = -EIO; 609 break; 610 } 611 if (s->crypt_method) { 612 if (!cluster_data) { 613 cluster_data = g_malloc0(s->cluster_size); 614 } 615 encrypt_sectors(s, sector_num, cluster_data, buf, 616 n, 1, &s->aes_encrypt_key); 617 src_buf = cluster_data; 618 } else { 619 src_buf = buf; 620 } 621 622 hd_iov.iov_base = (void *)src_buf; 623 hd_iov.iov_len = n * 512; 624 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 625 qemu_co_mutex_unlock(&s->lock); 626 ret = bdrv_co_writev(bs->file, 627 (cluster_offset >> 9) + index_in_cluster, 628 n, &hd_qiov); 629 qemu_co_mutex_lock(&s->lock); 630 if (ret < 0) { 631 break; 632 } 633 ret = 0; 634 635 nb_sectors -= n; 636 sector_num += n; 637 buf += n * 512; 638 } 639 qemu_co_mutex_unlock(&s->lock); 640 641 if (qiov->niov > 1) { 642 qemu_vfree(orig_buf); 643 } 644 g_free(cluster_data); 645 646 return ret; 647 } 648 649 static void qcow_close(BlockDriverState *bs) 650 { 651 BDRVQcowState *s = bs->opaque; 652 653 g_free(s->l1_table); 654 g_free(s->l2_cache); 655 g_free(s->cluster_cache); 656 g_free(s->cluster_data); 657 658 migrate_del_blocker(s->migration_blocker); 659 error_free(s->migration_blocker); 660 } 661 662 static int qcow_create(const char *filename, QEMUOptionParameter *options, 663 Error **errp) 664 { 665 int header_size, backing_filename_len, l1_size, shift, i; 666 QCowHeader header; 667 uint8_t *tmp; 668 int64_t total_size = 0; 669 const char *backing_file = NULL; 670 int flags = 0; 671 Error *local_err = NULL; 672 int ret; 673 BlockDriverState *qcow_bs; 674 675 /* Read out options */ 676 while (options && options->name) { 677 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 678 total_size = options->value.n / 512; 679 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 680 backing_file = options->value.s; 681 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 682 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 683 } 684 options++; 685 } 686 687 ret = bdrv_create_file(filename, options, &local_err); 688 if (ret < 0) { 689 qerror_report_err(local_err); 690 error_free(local_err); 691 return ret; 692 } 693 694 ret = bdrv_file_open(&qcow_bs, filename, NULL, NULL, BDRV_O_RDWR, 695 &local_err); 696 if (ret < 0) { 697 qerror_report_err(local_err); 698 error_free(local_err); 699 return ret; 700 } 701 702 ret = bdrv_truncate(qcow_bs, 0); 703 if (ret < 0) { 704 goto exit; 705 } 706 707 memset(&header, 0, sizeof(header)); 708 header.magic = cpu_to_be32(QCOW_MAGIC); 709 header.version = cpu_to_be32(QCOW_VERSION); 710 header.size = cpu_to_be64(total_size * 512); 711 header_size = sizeof(header); 712 backing_filename_len = 0; 713 if (backing_file) { 714 if (strcmp(backing_file, "fat:")) { 715 header.backing_file_offset = cpu_to_be64(header_size); 716 backing_filename_len = strlen(backing_file); 717 header.backing_file_size = cpu_to_be32(backing_filename_len); 718 header_size += backing_filename_len; 719 } else { 720 /* special backing file for vvfat */ 721 backing_file = NULL; 722 } 723 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 724 unmodifyed sectors */ 725 header.l2_bits = 12; /* 32 KB L2 tables */ 726 } else { 727 header.cluster_bits = 12; /* 4 KB clusters */ 728 header.l2_bits = 9; /* 4 KB L2 tables */ 729 } 730 header_size = (header_size + 7) & ~7; 731 shift = header.cluster_bits + header.l2_bits; 732 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 733 734 header.l1_table_offset = cpu_to_be64(header_size); 735 if (flags & BLOCK_FLAG_ENCRYPT) { 736 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 737 } else { 738 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 739 } 740 741 /* write all the data */ 742 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 743 if (ret != sizeof(header)) { 744 goto exit; 745 } 746 747 if (backing_file) { 748 ret = bdrv_pwrite(qcow_bs, sizeof(header), 749 backing_file, backing_filename_len); 750 if (ret != backing_filename_len) { 751 goto exit; 752 } 753 } 754 755 tmp = g_malloc0(BDRV_SECTOR_SIZE); 756 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 757 BDRV_SECTOR_SIZE); i++) { 758 ret = bdrv_pwrite(qcow_bs, header_size + 759 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 760 if (ret != BDRV_SECTOR_SIZE) { 761 g_free(tmp); 762 goto exit; 763 } 764 } 765 766 g_free(tmp); 767 ret = 0; 768 exit: 769 bdrv_unref(qcow_bs); 770 return ret; 771 } 772 773 static int qcow_make_empty(BlockDriverState *bs) 774 { 775 BDRVQcowState *s = bs->opaque; 776 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 777 int ret; 778 779 memset(s->l1_table, 0, l1_length); 780 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 781 l1_length) < 0) 782 return -1; 783 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 784 if (ret < 0) 785 return ret; 786 787 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 788 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 789 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 790 791 return 0; 792 } 793 794 /* XXX: put compressed sectors first, then all the cluster aligned 795 tables to avoid losing bytes in alignment */ 796 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 797 const uint8_t *buf, int nb_sectors) 798 { 799 BDRVQcowState *s = bs->opaque; 800 z_stream strm; 801 int ret, out_len; 802 uint8_t *out_buf; 803 uint64_t cluster_offset; 804 805 if (nb_sectors != s->cluster_sectors) { 806 ret = -EINVAL; 807 808 /* Zero-pad last write if image size is not cluster aligned */ 809 if (sector_num + nb_sectors == bs->total_sectors && 810 nb_sectors < s->cluster_sectors) { 811 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 812 memset(pad_buf, 0, s->cluster_size); 813 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 814 ret = qcow_write_compressed(bs, sector_num, 815 pad_buf, s->cluster_sectors); 816 qemu_vfree(pad_buf); 817 } 818 return ret; 819 } 820 821 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 822 823 /* best compression, small window, no zlib header */ 824 memset(&strm, 0, sizeof(strm)); 825 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 826 Z_DEFLATED, -12, 827 9, Z_DEFAULT_STRATEGY); 828 if (ret != 0) { 829 ret = -EINVAL; 830 goto fail; 831 } 832 833 strm.avail_in = s->cluster_size; 834 strm.next_in = (uint8_t *)buf; 835 strm.avail_out = s->cluster_size; 836 strm.next_out = out_buf; 837 838 ret = deflate(&strm, Z_FINISH); 839 if (ret != Z_STREAM_END && ret != Z_OK) { 840 deflateEnd(&strm); 841 ret = -EINVAL; 842 goto fail; 843 } 844 out_len = strm.next_out - out_buf; 845 846 deflateEnd(&strm); 847 848 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 849 /* could not compress: write normal cluster */ 850 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 851 if (ret < 0) { 852 goto fail; 853 } 854 } else { 855 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 856 out_len, 0, 0); 857 if (cluster_offset == 0) { 858 ret = -EIO; 859 goto fail; 860 } 861 862 cluster_offset &= s->cluster_offset_mask; 863 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 864 if (ret < 0) { 865 goto fail; 866 } 867 } 868 869 ret = 0; 870 fail: 871 g_free(out_buf); 872 return ret; 873 } 874 875 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 876 { 877 BDRVQcowState *s = bs->opaque; 878 bdi->cluster_size = s->cluster_size; 879 return 0; 880 } 881 882 883 static QEMUOptionParameter qcow_create_options[] = { 884 { 885 .name = BLOCK_OPT_SIZE, 886 .type = OPT_SIZE, 887 .help = "Virtual disk size" 888 }, 889 { 890 .name = BLOCK_OPT_BACKING_FILE, 891 .type = OPT_STRING, 892 .help = "File name of a base image" 893 }, 894 { 895 .name = BLOCK_OPT_ENCRYPT, 896 .type = OPT_FLAG, 897 .help = "Encrypt the image" 898 }, 899 { NULL } 900 }; 901 902 static BlockDriver bdrv_qcow = { 903 .format_name = "qcow", 904 .instance_size = sizeof(BDRVQcowState), 905 .bdrv_probe = qcow_probe, 906 .bdrv_open = qcow_open, 907 .bdrv_close = qcow_close, 908 .bdrv_reopen_prepare = qcow_reopen_prepare, 909 .bdrv_create = qcow_create, 910 .bdrv_has_zero_init = bdrv_has_zero_init_1, 911 912 .bdrv_co_readv = qcow_co_readv, 913 .bdrv_co_writev = qcow_co_writev, 914 .bdrv_co_get_block_status = qcow_co_get_block_status, 915 916 .bdrv_set_key = qcow_set_key, 917 .bdrv_make_empty = qcow_make_empty, 918 .bdrv_write_compressed = qcow_write_compressed, 919 .bdrv_get_info = qcow_get_info, 920 921 .create_options = qcow_create_options, 922 }; 923 924 static void bdrv_qcow_init(void) 925 { 926 bdrv_register(&bdrv_qcow); 927 } 928 929 block_init(bdrv_qcow_init); 930