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