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 error_setg(errp, "Image not in qcow format"); 117 ret = -EINVAL; 118 goto fail; 119 } 120 if (header.version != QCOW_VERSION) { 121 char version[64]; 122 snprintf(version, sizeof(version), "QCOW version %" PRIu32, 123 header.version); 124 error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 125 bs->device_name, "qcow", version); 126 ret = -ENOTSUP; 127 goto fail; 128 } 129 130 if (header.size <= 1 || header.cluster_bits < 9) { 131 error_setg(errp, "invalid value in qcow header"); 132 ret = -EINVAL; 133 goto fail; 134 } 135 if (header.crypt_method > QCOW_CRYPT_AES) { 136 error_setg(errp, "invalid encryption method in qcow header"); 137 ret = -EINVAL; 138 goto fail; 139 } 140 s->crypt_method_header = header.crypt_method; 141 if (s->crypt_method_header) { 142 bs->encrypted = 1; 143 } 144 s->cluster_bits = header.cluster_bits; 145 s->cluster_size = 1 << s->cluster_bits; 146 s->cluster_sectors = 1 << (s->cluster_bits - 9); 147 s->l2_bits = header.l2_bits; 148 s->l2_size = 1 << s->l2_bits; 149 bs->total_sectors = header.size / 512; 150 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 151 152 /* read the level 1 table */ 153 shift = s->cluster_bits + s->l2_bits; 154 s->l1_size = (header.size + (1LL << shift) - 1) >> shift; 155 156 s->l1_table_offset = header.l1_table_offset; 157 s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); 158 159 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 160 s->l1_size * sizeof(uint64_t)); 161 if (ret < 0) { 162 goto fail; 163 } 164 165 for(i = 0;i < s->l1_size; i++) { 166 be64_to_cpus(&s->l1_table[i]); 167 } 168 /* alloc L2 cache */ 169 s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 170 s->cluster_cache = g_malloc(s->cluster_size); 171 s->cluster_data = g_malloc(s->cluster_size); 172 s->cluster_cache_offset = -1; 173 174 /* read the backing file name */ 175 if (header.backing_file_offset != 0) { 176 len = header.backing_file_size; 177 if (len > 1023) { 178 len = 1023; 179 } 180 ret = bdrv_pread(bs->file, header.backing_file_offset, 181 bs->backing_file, len); 182 if (ret < 0) { 183 goto fail; 184 } 185 bs->backing_file[len] = '\0'; 186 } 187 188 /* Disable migration when qcow images are used */ 189 error_set(&s->migration_blocker, 190 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 191 "qcow", bs->device_name, "live migration"); 192 migrate_add_blocker(s->migration_blocker); 193 194 qemu_co_mutex_init(&s->lock); 195 return 0; 196 197 fail: 198 g_free(s->l1_table); 199 g_free(s->l2_cache); 200 g_free(s->cluster_cache); 201 g_free(s->cluster_data); 202 return ret; 203 } 204 205 206 /* We have nothing to do for QCOW reopen, stubs just return 207 * success */ 208 static int qcow_reopen_prepare(BDRVReopenState *state, 209 BlockReopenQueue *queue, Error **errp) 210 { 211 return 0; 212 } 213 214 static int qcow_set_key(BlockDriverState *bs, const char *key) 215 { 216 BDRVQcowState *s = bs->opaque; 217 uint8_t keybuf[16]; 218 int len, i; 219 220 memset(keybuf, 0, 16); 221 len = strlen(key); 222 if (len > 16) 223 len = 16; 224 /* XXX: we could compress the chars to 7 bits to increase 225 entropy */ 226 for(i = 0;i < len;i++) { 227 keybuf[i] = key[i]; 228 } 229 s->crypt_method = s->crypt_method_header; 230 231 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 232 return -1; 233 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 234 return -1; 235 return 0; 236 } 237 238 /* The crypt function is compatible with the linux cryptoloop 239 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 240 supported */ 241 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 242 uint8_t *out_buf, const uint8_t *in_buf, 243 int nb_sectors, int enc, 244 const AES_KEY *key) 245 { 246 union { 247 uint64_t ll[2]; 248 uint8_t b[16]; 249 } ivec; 250 int i; 251 252 for(i = 0; i < nb_sectors; i++) { 253 ivec.ll[0] = cpu_to_le64(sector_num); 254 ivec.ll[1] = 0; 255 AES_cbc_encrypt(in_buf, out_buf, 512, key, 256 ivec.b, enc); 257 sector_num++; 258 in_buf += 512; 259 out_buf += 512; 260 } 261 } 262 263 /* 'allocate' is: 264 * 265 * 0 to not allocate. 266 * 267 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 268 * 'n_end') 269 * 270 * 2 to allocate a compressed cluster of size 271 * 'compressed_size'. 'compressed_size' must be > 0 and < 272 * cluster_size 273 * 274 * return 0 if not allocated. 275 */ 276 static uint64_t get_cluster_offset(BlockDriverState *bs, 277 uint64_t offset, int allocate, 278 int compressed_size, 279 int n_start, int n_end) 280 { 281 BDRVQcowState *s = bs->opaque; 282 int min_index, i, j, l1_index, l2_index; 283 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 284 uint32_t min_count; 285 int new_l2_table; 286 287 l1_index = offset >> (s->l2_bits + s->cluster_bits); 288 l2_offset = s->l1_table[l1_index]; 289 new_l2_table = 0; 290 if (!l2_offset) { 291 if (!allocate) 292 return 0; 293 /* allocate a new l2 entry */ 294 l2_offset = bdrv_getlength(bs->file); 295 /* round to cluster size */ 296 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 297 /* update the L1 entry */ 298 s->l1_table[l1_index] = l2_offset; 299 tmp = cpu_to_be64(l2_offset); 300 if (bdrv_pwrite_sync(bs->file, 301 s->l1_table_offset + l1_index * sizeof(tmp), 302 &tmp, sizeof(tmp)) < 0) 303 return 0; 304 new_l2_table = 1; 305 } 306 for(i = 0; i < L2_CACHE_SIZE; i++) { 307 if (l2_offset == s->l2_cache_offsets[i]) { 308 /* increment the hit count */ 309 if (++s->l2_cache_counts[i] == 0xffffffff) { 310 for(j = 0; j < L2_CACHE_SIZE; j++) { 311 s->l2_cache_counts[j] >>= 1; 312 } 313 } 314 l2_table = s->l2_cache + (i << s->l2_bits); 315 goto found; 316 } 317 } 318 /* not found: load a new entry in the least used one */ 319 min_index = 0; 320 min_count = 0xffffffff; 321 for(i = 0; i < L2_CACHE_SIZE; i++) { 322 if (s->l2_cache_counts[i] < min_count) { 323 min_count = s->l2_cache_counts[i]; 324 min_index = i; 325 } 326 } 327 l2_table = s->l2_cache + (min_index << s->l2_bits); 328 if (new_l2_table) { 329 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 330 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 331 s->l2_size * sizeof(uint64_t)) < 0) 332 return 0; 333 } else { 334 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 335 s->l2_size * sizeof(uint64_t)) 336 return 0; 337 } 338 s->l2_cache_offsets[min_index] = l2_offset; 339 s->l2_cache_counts[min_index] = 1; 340 found: 341 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 342 cluster_offset = be64_to_cpu(l2_table[l2_index]); 343 if (!cluster_offset || 344 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 345 if (!allocate) 346 return 0; 347 /* allocate a new cluster */ 348 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 349 (n_end - n_start) < s->cluster_sectors) { 350 /* if the cluster is already compressed, we must 351 decompress it in the case it is not completely 352 overwritten */ 353 if (decompress_cluster(bs, cluster_offset) < 0) 354 return 0; 355 cluster_offset = bdrv_getlength(bs->file); 356 cluster_offset = (cluster_offset + s->cluster_size - 1) & 357 ~(s->cluster_size - 1); 358 /* write the cluster content */ 359 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 360 s->cluster_size) 361 return -1; 362 } else { 363 cluster_offset = bdrv_getlength(bs->file); 364 if (allocate == 1) { 365 /* round to cluster size */ 366 cluster_offset = (cluster_offset + s->cluster_size - 1) & 367 ~(s->cluster_size - 1); 368 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 369 /* if encrypted, we must initialize the cluster 370 content which won't be written */ 371 if (s->crypt_method && 372 (n_end - n_start) < s->cluster_sectors) { 373 uint64_t start_sect; 374 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 375 memset(s->cluster_data + 512, 0x00, 512); 376 for(i = 0; i < s->cluster_sectors; i++) { 377 if (i < n_start || i >= n_end) { 378 encrypt_sectors(s, start_sect + i, 379 s->cluster_data, 380 s->cluster_data + 512, 1, 1, 381 &s->aes_encrypt_key); 382 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 383 s->cluster_data, 512) != 512) 384 return -1; 385 } 386 } 387 } 388 } else if (allocate == 2) { 389 cluster_offset |= QCOW_OFLAG_COMPRESSED | 390 (uint64_t)compressed_size << (63 - s->cluster_bits); 391 } 392 } 393 /* update L2 table */ 394 tmp = cpu_to_be64(cluster_offset); 395 l2_table[l2_index] = tmp; 396 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 397 &tmp, sizeof(tmp)) < 0) 398 return 0; 399 } 400 return cluster_offset; 401 } 402 403 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 404 int64_t sector_num, int nb_sectors, int *pnum) 405 { 406 BDRVQcowState *s = bs->opaque; 407 int index_in_cluster, n; 408 uint64_t cluster_offset; 409 410 qemu_co_mutex_lock(&s->lock); 411 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 412 qemu_co_mutex_unlock(&s->lock); 413 index_in_cluster = sector_num & (s->cluster_sectors - 1); 414 n = s->cluster_sectors - index_in_cluster; 415 if (n > nb_sectors) 416 n = nb_sectors; 417 *pnum = n; 418 if (!cluster_offset) { 419 return 0; 420 } 421 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) { 422 return BDRV_BLOCK_DATA; 423 } 424 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 425 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 426 } 427 428 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 429 const uint8_t *buf, int buf_size) 430 { 431 z_stream strm1, *strm = &strm1; 432 int ret, out_len; 433 434 memset(strm, 0, sizeof(*strm)); 435 436 strm->next_in = (uint8_t *)buf; 437 strm->avail_in = buf_size; 438 strm->next_out = out_buf; 439 strm->avail_out = out_buf_size; 440 441 ret = inflateInit2(strm, -12); 442 if (ret != Z_OK) 443 return -1; 444 ret = inflate(strm, Z_FINISH); 445 out_len = strm->next_out - out_buf; 446 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 447 out_len != out_buf_size) { 448 inflateEnd(strm); 449 return -1; 450 } 451 inflateEnd(strm); 452 return 0; 453 } 454 455 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 456 { 457 BDRVQcowState *s = bs->opaque; 458 int ret, csize; 459 uint64_t coffset; 460 461 coffset = cluster_offset & s->cluster_offset_mask; 462 if (s->cluster_cache_offset != coffset) { 463 csize = cluster_offset >> (63 - s->cluster_bits); 464 csize &= (s->cluster_size - 1); 465 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 466 if (ret != csize) 467 return -1; 468 if (decompress_buffer(s->cluster_cache, s->cluster_size, 469 s->cluster_data, csize) < 0) { 470 return -1; 471 } 472 s->cluster_cache_offset = coffset; 473 } 474 return 0; 475 } 476 477 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 478 int nb_sectors, QEMUIOVector *qiov) 479 { 480 BDRVQcowState *s = bs->opaque; 481 int index_in_cluster; 482 int ret = 0, n; 483 uint64_t cluster_offset; 484 struct iovec hd_iov; 485 QEMUIOVector hd_qiov; 486 uint8_t *buf; 487 void *orig_buf; 488 489 if (qiov->niov > 1) { 490 buf = orig_buf = qemu_blockalign(bs, qiov->size); 491 } else { 492 orig_buf = NULL; 493 buf = (uint8_t *)qiov->iov->iov_base; 494 } 495 496 qemu_co_mutex_lock(&s->lock); 497 498 while (nb_sectors != 0) { 499 /* prepare next request */ 500 cluster_offset = get_cluster_offset(bs, sector_num << 9, 501 0, 0, 0, 0); 502 index_in_cluster = sector_num & (s->cluster_sectors - 1); 503 n = s->cluster_sectors - index_in_cluster; 504 if (n > nb_sectors) { 505 n = nb_sectors; 506 } 507 508 if (!cluster_offset) { 509 if (bs->backing_hd) { 510 /* read from the base image */ 511 hd_iov.iov_base = (void *)buf; 512 hd_iov.iov_len = n * 512; 513 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 514 qemu_co_mutex_unlock(&s->lock); 515 ret = bdrv_co_readv(bs->backing_hd, sector_num, 516 n, &hd_qiov); 517 qemu_co_mutex_lock(&s->lock); 518 if (ret < 0) { 519 goto fail; 520 } 521 } else { 522 /* Note: in this case, no need to wait */ 523 memset(buf, 0, 512 * n); 524 } 525 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 526 /* add AIO support for compressed blocks ? */ 527 if (decompress_cluster(bs, cluster_offset) < 0) { 528 goto fail; 529 } 530 memcpy(buf, 531 s->cluster_cache + index_in_cluster * 512, 512 * n); 532 } else { 533 if ((cluster_offset & 511) != 0) { 534 goto fail; 535 } 536 hd_iov.iov_base = (void *)buf; 537 hd_iov.iov_len = n * 512; 538 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 539 qemu_co_mutex_unlock(&s->lock); 540 ret = bdrv_co_readv(bs->file, 541 (cluster_offset >> 9) + index_in_cluster, 542 n, &hd_qiov); 543 qemu_co_mutex_lock(&s->lock); 544 if (ret < 0) { 545 break; 546 } 547 if (s->crypt_method) { 548 encrypt_sectors(s, sector_num, buf, buf, 549 n, 0, 550 &s->aes_decrypt_key); 551 } 552 } 553 ret = 0; 554 555 nb_sectors -= n; 556 sector_num += n; 557 buf += n * 512; 558 } 559 560 done: 561 qemu_co_mutex_unlock(&s->lock); 562 563 if (qiov->niov > 1) { 564 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 565 qemu_vfree(orig_buf); 566 } 567 568 return ret; 569 570 fail: 571 ret = -EIO; 572 goto done; 573 } 574 575 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 576 int nb_sectors, QEMUIOVector *qiov) 577 { 578 BDRVQcowState *s = bs->opaque; 579 int index_in_cluster; 580 uint64_t cluster_offset; 581 const uint8_t *src_buf; 582 int ret = 0, n; 583 uint8_t *cluster_data = NULL; 584 struct iovec hd_iov; 585 QEMUIOVector hd_qiov; 586 uint8_t *buf; 587 void *orig_buf; 588 589 s->cluster_cache_offset = -1; /* disable compressed cache */ 590 591 if (qiov->niov > 1) { 592 buf = orig_buf = qemu_blockalign(bs, qiov->size); 593 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 594 } else { 595 orig_buf = NULL; 596 buf = (uint8_t *)qiov->iov->iov_base; 597 } 598 599 qemu_co_mutex_lock(&s->lock); 600 601 while (nb_sectors != 0) { 602 603 index_in_cluster = sector_num & (s->cluster_sectors - 1); 604 n = s->cluster_sectors - index_in_cluster; 605 if (n > nb_sectors) { 606 n = nb_sectors; 607 } 608 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 609 index_in_cluster, 610 index_in_cluster + n); 611 if (!cluster_offset || (cluster_offset & 511) != 0) { 612 ret = -EIO; 613 break; 614 } 615 if (s->crypt_method) { 616 if (!cluster_data) { 617 cluster_data = g_malloc0(s->cluster_size); 618 } 619 encrypt_sectors(s, sector_num, cluster_data, buf, 620 n, 1, &s->aes_encrypt_key); 621 src_buf = cluster_data; 622 } else { 623 src_buf = buf; 624 } 625 626 hd_iov.iov_base = (void *)src_buf; 627 hd_iov.iov_len = n * 512; 628 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 629 qemu_co_mutex_unlock(&s->lock); 630 ret = bdrv_co_writev(bs->file, 631 (cluster_offset >> 9) + index_in_cluster, 632 n, &hd_qiov); 633 qemu_co_mutex_lock(&s->lock); 634 if (ret < 0) { 635 break; 636 } 637 ret = 0; 638 639 nb_sectors -= n; 640 sector_num += n; 641 buf += n * 512; 642 } 643 qemu_co_mutex_unlock(&s->lock); 644 645 if (qiov->niov > 1) { 646 qemu_vfree(orig_buf); 647 } 648 g_free(cluster_data); 649 650 return ret; 651 } 652 653 static void qcow_close(BlockDriverState *bs) 654 { 655 BDRVQcowState *s = bs->opaque; 656 657 g_free(s->l1_table); 658 g_free(s->l2_cache); 659 g_free(s->cluster_cache); 660 g_free(s->cluster_data); 661 662 migrate_del_blocker(s->migration_blocker); 663 error_free(s->migration_blocker); 664 } 665 666 static int qcow_create(const char *filename, QEMUOptionParameter *options, 667 Error **errp) 668 { 669 int header_size, backing_filename_len, l1_size, shift, i; 670 QCowHeader header; 671 uint8_t *tmp; 672 int64_t total_size = 0; 673 const char *backing_file = NULL; 674 int flags = 0; 675 Error *local_err = NULL; 676 int ret; 677 BlockDriverState *qcow_bs; 678 679 /* Read out options */ 680 while (options && options->name) { 681 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 682 total_size = options->value.n / 512; 683 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 684 backing_file = options->value.s; 685 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 686 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 687 } 688 options++; 689 } 690 691 ret = bdrv_create_file(filename, options, &local_err); 692 if (ret < 0) { 693 error_propagate(errp, local_err); 694 return ret; 695 } 696 697 qcow_bs = NULL; 698 ret = bdrv_open(&qcow_bs, filename, NULL, NULL, 699 BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err); 700 if (ret < 0) { 701 error_propagate(errp, local_err); 702 return ret; 703 } 704 705 ret = bdrv_truncate(qcow_bs, 0); 706 if (ret < 0) { 707 goto exit; 708 } 709 710 memset(&header, 0, sizeof(header)); 711 header.magic = cpu_to_be32(QCOW_MAGIC); 712 header.version = cpu_to_be32(QCOW_VERSION); 713 header.size = cpu_to_be64(total_size * 512); 714 header_size = sizeof(header); 715 backing_filename_len = 0; 716 if (backing_file) { 717 if (strcmp(backing_file, "fat:")) { 718 header.backing_file_offset = cpu_to_be64(header_size); 719 backing_filename_len = strlen(backing_file); 720 header.backing_file_size = cpu_to_be32(backing_filename_len); 721 header_size += backing_filename_len; 722 } else { 723 /* special backing file for vvfat */ 724 backing_file = NULL; 725 } 726 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 727 unmodified sectors */ 728 header.l2_bits = 12; /* 32 KB L2 tables */ 729 } else { 730 header.cluster_bits = 12; /* 4 KB clusters */ 731 header.l2_bits = 9; /* 4 KB L2 tables */ 732 } 733 header_size = (header_size + 7) & ~7; 734 shift = header.cluster_bits + header.l2_bits; 735 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 736 737 header.l1_table_offset = cpu_to_be64(header_size); 738 if (flags & BLOCK_FLAG_ENCRYPT) { 739 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 740 } else { 741 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 742 } 743 744 /* write all the data */ 745 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 746 if (ret != sizeof(header)) { 747 goto exit; 748 } 749 750 if (backing_file) { 751 ret = bdrv_pwrite(qcow_bs, sizeof(header), 752 backing_file, backing_filename_len); 753 if (ret != backing_filename_len) { 754 goto exit; 755 } 756 } 757 758 tmp = g_malloc0(BDRV_SECTOR_SIZE); 759 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 760 BDRV_SECTOR_SIZE); i++) { 761 ret = bdrv_pwrite(qcow_bs, header_size + 762 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 763 if (ret != BDRV_SECTOR_SIZE) { 764 g_free(tmp); 765 goto exit; 766 } 767 } 768 769 g_free(tmp); 770 ret = 0; 771 exit: 772 bdrv_unref(qcow_bs); 773 return ret; 774 } 775 776 static int qcow_make_empty(BlockDriverState *bs) 777 { 778 BDRVQcowState *s = bs->opaque; 779 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 780 int ret; 781 782 memset(s->l1_table, 0, l1_length); 783 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 784 l1_length) < 0) 785 return -1; 786 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 787 if (ret < 0) 788 return ret; 789 790 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 791 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 792 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 793 794 return 0; 795 } 796 797 /* XXX: put compressed sectors first, then all the cluster aligned 798 tables to avoid losing bytes in alignment */ 799 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 800 const uint8_t *buf, int nb_sectors) 801 { 802 BDRVQcowState *s = bs->opaque; 803 z_stream strm; 804 int ret, out_len; 805 uint8_t *out_buf; 806 uint64_t cluster_offset; 807 808 if (nb_sectors != s->cluster_sectors) { 809 ret = -EINVAL; 810 811 /* Zero-pad last write if image size is not cluster aligned */ 812 if (sector_num + nb_sectors == bs->total_sectors && 813 nb_sectors < s->cluster_sectors) { 814 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 815 memset(pad_buf, 0, s->cluster_size); 816 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 817 ret = qcow_write_compressed(bs, sector_num, 818 pad_buf, s->cluster_sectors); 819 qemu_vfree(pad_buf); 820 } 821 return ret; 822 } 823 824 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 825 826 /* best compression, small window, no zlib header */ 827 memset(&strm, 0, sizeof(strm)); 828 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 829 Z_DEFLATED, -12, 830 9, Z_DEFAULT_STRATEGY); 831 if (ret != 0) { 832 ret = -EINVAL; 833 goto fail; 834 } 835 836 strm.avail_in = s->cluster_size; 837 strm.next_in = (uint8_t *)buf; 838 strm.avail_out = s->cluster_size; 839 strm.next_out = out_buf; 840 841 ret = deflate(&strm, Z_FINISH); 842 if (ret != Z_STREAM_END && ret != Z_OK) { 843 deflateEnd(&strm); 844 ret = -EINVAL; 845 goto fail; 846 } 847 out_len = strm.next_out - out_buf; 848 849 deflateEnd(&strm); 850 851 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 852 /* could not compress: write normal cluster */ 853 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 854 if (ret < 0) { 855 goto fail; 856 } 857 } else { 858 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 859 out_len, 0, 0); 860 if (cluster_offset == 0) { 861 ret = -EIO; 862 goto fail; 863 } 864 865 cluster_offset &= s->cluster_offset_mask; 866 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 867 if (ret < 0) { 868 goto fail; 869 } 870 } 871 872 ret = 0; 873 fail: 874 g_free(out_buf); 875 return ret; 876 } 877 878 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 879 { 880 BDRVQcowState *s = bs->opaque; 881 bdi->cluster_size = s->cluster_size; 882 return 0; 883 } 884 885 886 static QEMUOptionParameter qcow_create_options[] = { 887 { 888 .name = BLOCK_OPT_SIZE, 889 .type = OPT_SIZE, 890 .help = "Virtual disk size" 891 }, 892 { 893 .name = BLOCK_OPT_BACKING_FILE, 894 .type = OPT_STRING, 895 .help = "File name of a base image" 896 }, 897 { 898 .name = BLOCK_OPT_ENCRYPT, 899 .type = OPT_FLAG, 900 .help = "Encrypt the image" 901 }, 902 { NULL } 903 }; 904 905 static BlockDriver bdrv_qcow = { 906 .format_name = "qcow", 907 .instance_size = sizeof(BDRVQcowState), 908 .bdrv_probe = qcow_probe, 909 .bdrv_open = qcow_open, 910 .bdrv_close = qcow_close, 911 .bdrv_reopen_prepare = qcow_reopen_prepare, 912 .bdrv_create = qcow_create, 913 .bdrv_has_zero_init = bdrv_has_zero_init_1, 914 915 .bdrv_co_readv = qcow_co_readv, 916 .bdrv_co_writev = qcow_co_writev, 917 .bdrv_co_get_block_status = qcow_co_get_block_status, 918 919 .bdrv_set_key = qcow_set_key, 920 .bdrv_make_empty = qcow_make_empty, 921 .bdrv_write_compressed = qcow_write_compressed, 922 .bdrv_get_info = qcow_get_info, 923 924 .create_options = qcow_create_options, 925 }; 926 927 static void bdrv_qcow_init(void) 928 { 929 bdrv_register(&bdrv_qcow); 930 } 931 932 block_init(bdrv_qcow_init); 933