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 uint16_t padding; 52 uint32_t crypt_method; 53 uint64_t l1_table_offset; 54 } QEMU_PACKED QCowHeader; 55 56 #define L2_CACHE_SIZE 16 57 58 typedef struct BDRVQcowState { 59 int cluster_bits; 60 int cluster_size; 61 int cluster_sectors; 62 int l2_bits; 63 int l2_size; 64 unsigned int l1_size; 65 uint64_t cluster_offset_mask; 66 uint64_t l1_table_offset; 67 uint64_t *l1_table; 68 uint64_t *l2_cache; 69 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 70 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 71 uint8_t *cluster_cache; 72 uint8_t *cluster_data; 73 uint64_t cluster_cache_offset; 74 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 75 uint32_t crypt_method_header; 76 AES_KEY aes_encrypt_key; 77 AES_KEY aes_decrypt_key; 78 CoMutex lock; 79 Error *migration_blocker; 80 } BDRVQcowState; 81 82 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 83 84 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 85 { 86 const QCowHeader *cow_header = (const void *)buf; 87 88 if (buf_size >= sizeof(QCowHeader) && 89 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 90 be32_to_cpu(cow_header->version) == QCOW_VERSION) 91 return 100; 92 else 93 return 0; 94 } 95 96 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 97 Error **errp) 98 { 99 BDRVQcowState *s = bs->opaque; 100 unsigned int len, i, shift; 101 int ret; 102 QCowHeader header; 103 104 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 105 if (ret < 0) { 106 goto fail; 107 } 108 be32_to_cpus(&header.magic); 109 be32_to_cpus(&header.version); 110 be64_to_cpus(&header.backing_file_offset); 111 be32_to_cpus(&header.backing_file_size); 112 be32_to_cpus(&header.mtime); 113 be64_to_cpus(&header.size); 114 be32_to_cpus(&header.crypt_method); 115 be64_to_cpus(&header.l1_table_offset); 116 117 if (header.magic != QCOW_MAGIC) { 118 error_setg(errp, "Image not in qcow format"); 119 ret = -EINVAL; 120 goto fail; 121 } 122 if (header.version != QCOW_VERSION) { 123 char version[64]; 124 snprintf(version, sizeof(version), "QCOW version %" PRIu32, 125 header.version); 126 error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 127 bs->device_name, "qcow", version); 128 ret = -ENOTSUP; 129 goto fail; 130 } 131 132 if (header.size <= 1) { 133 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 134 ret = -EINVAL; 135 goto fail; 136 } 137 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 138 error_setg(errp, "Cluster size must be between 512 and 64k"); 139 ret = -EINVAL; 140 goto fail; 141 } 142 143 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 144 * so bytes = num_entries << 3. */ 145 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 146 error_setg(errp, "L2 table size must be between 512 and 64k"); 147 ret = -EINVAL; 148 goto fail; 149 } 150 151 if (header.crypt_method > QCOW_CRYPT_AES) { 152 error_setg(errp, "invalid encryption method in qcow header"); 153 ret = -EINVAL; 154 goto fail; 155 } 156 s->crypt_method_header = header.crypt_method; 157 if (s->crypt_method_header) { 158 bs->encrypted = 1; 159 } 160 s->cluster_bits = header.cluster_bits; 161 s->cluster_size = 1 << s->cluster_bits; 162 s->cluster_sectors = 1 << (s->cluster_bits - 9); 163 s->l2_bits = header.l2_bits; 164 s->l2_size = 1 << s->l2_bits; 165 bs->total_sectors = header.size / 512; 166 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 167 168 /* read the level 1 table */ 169 shift = s->cluster_bits + s->l2_bits; 170 if (header.size > UINT64_MAX - (1LL << shift)) { 171 error_setg(errp, "Image too large"); 172 ret = -EINVAL; 173 goto fail; 174 } else { 175 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 176 if (l1_size > INT_MAX / sizeof(uint64_t)) { 177 error_setg(errp, "Image too large"); 178 ret = -EINVAL; 179 goto fail; 180 } 181 s->l1_size = l1_size; 182 } 183 184 s->l1_table_offset = header.l1_table_offset; 185 s->l1_table = g_try_new(uint64_t, s->l1_size); 186 if (s->l1_table == NULL) { 187 error_setg(errp, "Could not allocate memory for L1 table"); 188 ret = -ENOMEM; 189 goto fail; 190 } 191 192 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 193 s->l1_size * sizeof(uint64_t)); 194 if (ret < 0) { 195 goto fail; 196 } 197 198 for(i = 0;i < s->l1_size; i++) { 199 be64_to_cpus(&s->l1_table[i]); 200 } 201 202 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 203 s->l2_cache = 204 qemu_try_blockalign(bs->file, 205 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 206 if (s->l2_cache == NULL) { 207 error_setg(errp, "Could not allocate L2 table cache"); 208 ret = -ENOMEM; 209 goto fail; 210 } 211 s->cluster_cache = g_malloc(s->cluster_size); 212 s->cluster_data = g_malloc(s->cluster_size); 213 s->cluster_cache_offset = -1; 214 215 /* read the backing file name */ 216 if (header.backing_file_offset != 0) { 217 len = header.backing_file_size; 218 if (len > 1023) { 219 error_setg(errp, "Backing file name too long"); 220 ret = -EINVAL; 221 goto fail; 222 } 223 ret = bdrv_pread(bs->file, header.backing_file_offset, 224 bs->backing_file, len); 225 if (ret < 0) { 226 goto fail; 227 } 228 bs->backing_file[len] = '\0'; 229 } 230 231 /* Disable migration when qcow images are used */ 232 error_set(&s->migration_blocker, 233 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 234 "qcow", bs->device_name, "live migration"); 235 migrate_add_blocker(s->migration_blocker); 236 237 qemu_co_mutex_init(&s->lock); 238 return 0; 239 240 fail: 241 g_free(s->l1_table); 242 qemu_vfree(s->l2_cache); 243 g_free(s->cluster_cache); 244 g_free(s->cluster_data); 245 return ret; 246 } 247 248 249 /* We have nothing to do for QCOW reopen, stubs just return 250 * success */ 251 static int qcow_reopen_prepare(BDRVReopenState *state, 252 BlockReopenQueue *queue, Error **errp) 253 { 254 return 0; 255 } 256 257 static int qcow_set_key(BlockDriverState *bs, const char *key) 258 { 259 BDRVQcowState *s = bs->opaque; 260 uint8_t keybuf[16]; 261 int len, i; 262 263 memset(keybuf, 0, 16); 264 len = strlen(key); 265 if (len > 16) 266 len = 16; 267 /* XXX: we could compress the chars to 7 bits to increase 268 entropy */ 269 for(i = 0;i < len;i++) { 270 keybuf[i] = key[i]; 271 } 272 s->crypt_method = s->crypt_method_header; 273 274 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 275 return -1; 276 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 277 return -1; 278 return 0; 279 } 280 281 /* The crypt function is compatible with the linux cryptoloop 282 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 283 supported */ 284 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 285 uint8_t *out_buf, const uint8_t *in_buf, 286 int nb_sectors, int enc, 287 const AES_KEY *key) 288 { 289 union { 290 uint64_t ll[2]; 291 uint8_t b[16]; 292 } ivec; 293 int i; 294 295 for(i = 0; i < nb_sectors; i++) { 296 ivec.ll[0] = cpu_to_le64(sector_num); 297 ivec.ll[1] = 0; 298 AES_cbc_encrypt(in_buf, out_buf, 512, key, 299 ivec.b, enc); 300 sector_num++; 301 in_buf += 512; 302 out_buf += 512; 303 } 304 } 305 306 /* 'allocate' is: 307 * 308 * 0 to not allocate. 309 * 310 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 311 * 'n_end') 312 * 313 * 2 to allocate a compressed cluster of size 314 * 'compressed_size'. 'compressed_size' must be > 0 and < 315 * cluster_size 316 * 317 * return 0 if not allocated. 318 */ 319 static uint64_t get_cluster_offset(BlockDriverState *bs, 320 uint64_t offset, int allocate, 321 int compressed_size, 322 int n_start, int n_end) 323 { 324 BDRVQcowState *s = bs->opaque; 325 int min_index, i, j, l1_index, l2_index; 326 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 327 uint32_t min_count; 328 int new_l2_table; 329 330 l1_index = offset >> (s->l2_bits + s->cluster_bits); 331 l2_offset = s->l1_table[l1_index]; 332 new_l2_table = 0; 333 if (!l2_offset) { 334 if (!allocate) 335 return 0; 336 /* allocate a new l2 entry */ 337 l2_offset = bdrv_getlength(bs->file); 338 /* round to cluster size */ 339 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 340 /* update the L1 entry */ 341 s->l1_table[l1_index] = l2_offset; 342 tmp = cpu_to_be64(l2_offset); 343 if (bdrv_pwrite_sync(bs->file, 344 s->l1_table_offset + l1_index * sizeof(tmp), 345 &tmp, sizeof(tmp)) < 0) 346 return 0; 347 new_l2_table = 1; 348 } 349 for(i = 0; i < L2_CACHE_SIZE; i++) { 350 if (l2_offset == s->l2_cache_offsets[i]) { 351 /* increment the hit count */ 352 if (++s->l2_cache_counts[i] == 0xffffffff) { 353 for(j = 0; j < L2_CACHE_SIZE; j++) { 354 s->l2_cache_counts[j] >>= 1; 355 } 356 } 357 l2_table = s->l2_cache + (i << s->l2_bits); 358 goto found; 359 } 360 } 361 /* not found: load a new entry in the least used one */ 362 min_index = 0; 363 min_count = 0xffffffff; 364 for(i = 0; i < L2_CACHE_SIZE; i++) { 365 if (s->l2_cache_counts[i] < min_count) { 366 min_count = s->l2_cache_counts[i]; 367 min_index = i; 368 } 369 } 370 l2_table = s->l2_cache + (min_index << s->l2_bits); 371 if (new_l2_table) { 372 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 373 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 374 s->l2_size * sizeof(uint64_t)) < 0) 375 return 0; 376 } else { 377 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 378 s->l2_size * sizeof(uint64_t)) 379 return 0; 380 } 381 s->l2_cache_offsets[min_index] = l2_offset; 382 s->l2_cache_counts[min_index] = 1; 383 found: 384 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 385 cluster_offset = be64_to_cpu(l2_table[l2_index]); 386 if (!cluster_offset || 387 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 388 if (!allocate) 389 return 0; 390 /* allocate a new cluster */ 391 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 392 (n_end - n_start) < s->cluster_sectors) { 393 /* if the cluster is already compressed, we must 394 decompress it in the case it is not completely 395 overwritten */ 396 if (decompress_cluster(bs, cluster_offset) < 0) 397 return 0; 398 cluster_offset = bdrv_getlength(bs->file); 399 cluster_offset = (cluster_offset + s->cluster_size - 1) & 400 ~(s->cluster_size - 1); 401 /* write the cluster content */ 402 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 403 s->cluster_size) 404 return -1; 405 } else { 406 cluster_offset = bdrv_getlength(bs->file); 407 if (allocate == 1) { 408 /* round to cluster size */ 409 cluster_offset = (cluster_offset + s->cluster_size - 1) & 410 ~(s->cluster_size - 1); 411 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 412 /* if encrypted, we must initialize the cluster 413 content which won't be written */ 414 if (s->crypt_method && 415 (n_end - n_start) < s->cluster_sectors) { 416 uint64_t start_sect; 417 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 418 memset(s->cluster_data + 512, 0x00, 512); 419 for(i = 0; i < s->cluster_sectors; i++) { 420 if (i < n_start || i >= n_end) { 421 encrypt_sectors(s, start_sect + i, 422 s->cluster_data, 423 s->cluster_data + 512, 1, 1, 424 &s->aes_encrypt_key); 425 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 426 s->cluster_data, 512) != 512) 427 return -1; 428 } 429 } 430 } 431 } else if (allocate == 2) { 432 cluster_offset |= QCOW_OFLAG_COMPRESSED | 433 (uint64_t)compressed_size << (63 - s->cluster_bits); 434 } 435 } 436 /* update L2 table */ 437 tmp = cpu_to_be64(cluster_offset); 438 l2_table[l2_index] = tmp; 439 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 440 &tmp, sizeof(tmp)) < 0) 441 return 0; 442 } 443 return cluster_offset; 444 } 445 446 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 447 int64_t sector_num, int nb_sectors, int *pnum) 448 { 449 BDRVQcowState *s = bs->opaque; 450 int index_in_cluster, n; 451 uint64_t cluster_offset; 452 453 qemu_co_mutex_lock(&s->lock); 454 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 455 qemu_co_mutex_unlock(&s->lock); 456 index_in_cluster = sector_num & (s->cluster_sectors - 1); 457 n = s->cluster_sectors - index_in_cluster; 458 if (n > nb_sectors) 459 n = nb_sectors; 460 *pnum = n; 461 if (!cluster_offset) { 462 return 0; 463 } 464 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) { 465 return BDRV_BLOCK_DATA; 466 } 467 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 468 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 469 } 470 471 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 472 const uint8_t *buf, int buf_size) 473 { 474 z_stream strm1, *strm = &strm1; 475 int ret, out_len; 476 477 memset(strm, 0, sizeof(*strm)); 478 479 strm->next_in = (uint8_t *)buf; 480 strm->avail_in = buf_size; 481 strm->next_out = out_buf; 482 strm->avail_out = out_buf_size; 483 484 ret = inflateInit2(strm, -12); 485 if (ret != Z_OK) 486 return -1; 487 ret = inflate(strm, Z_FINISH); 488 out_len = strm->next_out - out_buf; 489 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 490 out_len != out_buf_size) { 491 inflateEnd(strm); 492 return -1; 493 } 494 inflateEnd(strm); 495 return 0; 496 } 497 498 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 499 { 500 BDRVQcowState *s = bs->opaque; 501 int ret, csize; 502 uint64_t coffset; 503 504 coffset = cluster_offset & s->cluster_offset_mask; 505 if (s->cluster_cache_offset != coffset) { 506 csize = cluster_offset >> (63 - s->cluster_bits); 507 csize &= (s->cluster_size - 1); 508 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 509 if (ret != csize) 510 return -1; 511 if (decompress_buffer(s->cluster_cache, s->cluster_size, 512 s->cluster_data, csize) < 0) { 513 return -1; 514 } 515 s->cluster_cache_offset = coffset; 516 } 517 return 0; 518 } 519 520 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 521 int nb_sectors, QEMUIOVector *qiov) 522 { 523 BDRVQcowState *s = bs->opaque; 524 int index_in_cluster; 525 int ret = 0, n; 526 uint64_t cluster_offset; 527 struct iovec hd_iov; 528 QEMUIOVector hd_qiov; 529 uint8_t *buf; 530 void *orig_buf; 531 532 if (qiov->niov > 1) { 533 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 534 if (buf == NULL) { 535 return -ENOMEM; 536 } 537 } else { 538 orig_buf = NULL; 539 buf = (uint8_t *)qiov->iov->iov_base; 540 } 541 542 qemu_co_mutex_lock(&s->lock); 543 544 while (nb_sectors != 0) { 545 /* prepare next request */ 546 cluster_offset = get_cluster_offset(bs, sector_num << 9, 547 0, 0, 0, 0); 548 index_in_cluster = sector_num & (s->cluster_sectors - 1); 549 n = s->cluster_sectors - index_in_cluster; 550 if (n > nb_sectors) { 551 n = nb_sectors; 552 } 553 554 if (!cluster_offset) { 555 if (bs->backing_hd) { 556 /* read from the base image */ 557 hd_iov.iov_base = (void *)buf; 558 hd_iov.iov_len = n * 512; 559 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 560 qemu_co_mutex_unlock(&s->lock); 561 ret = bdrv_co_readv(bs->backing_hd, sector_num, 562 n, &hd_qiov); 563 qemu_co_mutex_lock(&s->lock); 564 if (ret < 0) { 565 goto fail; 566 } 567 } else { 568 /* Note: in this case, no need to wait */ 569 memset(buf, 0, 512 * n); 570 } 571 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 572 /* add AIO support for compressed blocks ? */ 573 if (decompress_cluster(bs, cluster_offset) < 0) { 574 goto fail; 575 } 576 memcpy(buf, 577 s->cluster_cache + index_in_cluster * 512, 512 * n); 578 } else { 579 if ((cluster_offset & 511) != 0) { 580 goto fail; 581 } 582 hd_iov.iov_base = (void *)buf; 583 hd_iov.iov_len = n * 512; 584 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 585 qemu_co_mutex_unlock(&s->lock); 586 ret = bdrv_co_readv(bs->file, 587 (cluster_offset >> 9) + index_in_cluster, 588 n, &hd_qiov); 589 qemu_co_mutex_lock(&s->lock); 590 if (ret < 0) { 591 break; 592 } 593 if (s->crypt_method) { 594 encrypt_sectors(s, sector_num, buf, buf, 595 n, 0, 596 &s->aes_decrypt_key); 597 } 598 } 599 ret = 0; 600 601 nb_sectors -= n; 602 sector_num += n; 603 buf += n * 512; 604 } 605 606 done: 607 qemu_co_mutex_unlock(&s->lock); 608 609 if (qiov->niov > 1) { 610 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 611 qemu_vfree(orig_buf); 612 } 613 614 return ret; 615 616 fail: 617 ret = -EIO; 618 goto done; 619 } 620 621 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 622 int nb_sectors, QEMUIOVector *qiov) 623 { 624 BDRVQcowState *s = bs->opaque; 625 int index_in_cluster; 626 uint64_t cluster_offset; 627 const uint8_t *src_buf; 628 int ret = 0, n; 629 uint8_t *cluster_data = NULL; 630 struct iovec hd_iov; 631 QEMUIOVector hd_qiov; 632 uint8_t *buf; 633 void *orig_buf; 634 635 s->cluster_cache_offset = -1; /* disable compressed cache */ 636 637 if (qiov->niov > 1) { 638 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 639 if (buf == NULL) { 640 return -ENOMEM; 641 } 642 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 643 } else { 644 orig_buf = NULL; 645 buf = (uint8_t *)qiov->iov->iov_base; 646 } 647 648 qemu_co_mutex_lock(&s->lock); 649 650 while (nb_sectors != 0) { 651 652 index_in_cluster = sector_num & (s->cluster_sectors - 1); 653 n = s->cluster_sectors - index_in_cluster; 654 if (n > nb_sectors) { 655 n = nb_sectors; 656 } 657 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 658 index_in_cluster, 659 index_in_cluster + n); 660 if (!cluster_offset || (cluster_offset & 511) != 0) { 661 ret = -EIO; 662 break; 663 } 664 if (s->crypt_method) { 665 if (!cluster_data) { 666 cluster_data = g_malloc0(s->cluster_size); 667 } 668 encrypt_sectors(s, sector_num, cluster_data, buf, 669 n, 1, &s->aes_encrypt_key); 670 src_buf = cluster_data; 671 } else { 672 src_buf = buf; 673 } 674 675 hd_iov.iov_base = (void *)src_buf; 676 hd_iov.iov_len = n * 512; 677 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 678 qemu_co_mutex_unlock(&s->lock); 679 ret = bdrv_co_writev(bs->file, 680 (cluster_offset >> 9) + index_in_cluster, 681 n, &hd_qiov); 682 qemu_co_mutex_lock(&s->lock); 683 if (ret < 0) { 684 break; 685 } 686 ret = 0; 687 688 nb_sectors -= n; 689 sector_num += n; 690 buf += n * 512; 691 } 692 qemu_co_mutex_unlock(&s->lock); 693 694 if (qiov->niov > 1) { 695 qemu_vfree(orig_buf); 696 } 697 g_free(cluster_data); 698 699 return ret; 700 } 701 702 static void qcow_close(BlockDriverState *bs) 703 { 704 BDRVQcowState *s = bs->opaque; 705 706 g_free(s->l1_table); 707 qemu_vfree(s->l2_cache); 708 g_free(s->cluster_cache); 709 g_free(s->cluster_data); 710 711 migrate_del_blocker(s->migration_blocker); 712 error_free(s->migration_blocker); 713 } 714 715 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 716 { 717 int header_size, backing_filename_len, l1_size, shift, i; 718 QCowHeader header; 719 uint8_t *tmp; 720 int64_t total_size = 0; 721 char *backing_file = NULL; 722 int flags = 0; 723 Error *local_err = NULL; 724 int ret; 725 BlockDriverState *qcow_bs; 726 727 /* Read out options */ 728 total_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / 512; 729 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 730 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 731 flags |= BLOCK_FLAG_ENCRYPT; 732 } 733 734 ret = bdrv_create_file(filename, opts, &local_err); 735 if (ret < 0) { 736 error_propagate(errp, local_err); 737 goto cleanup; 738 } 739 740 qcow_bs = NULL; 741 ret = bdrv_open(&qcow_bs, filename, NULL, NULL, 742 BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err); 743 if (ret < 0) { 744 error_propagate(errp, local_err); 745 goto cleanup; 746 } 747 748 ret = bdrv_truncate(qcow_bs, 0); 749 if (ret < 0) { 750 goto exit; 751 } 752 753 memset(&header, 0, sizeof(header)); 754 header.magic = cpu_to_be32(QCOW_MAGIC); 755 header.version = cpu_to_be32(QCOW_VERSION); 756 header.size = cpu_to_be64(total_size * 512); 757 header_size = sizeof(header); 758 backing_filename_len = 0; 759 if (backing_file) { 760 if (strcmp(backing_file, "fat:")) { 761 header.backing_file_offset = cpu_to_be64(header_size); 762 backing_filename_len = strlen(backing_file); 763 header.backing_file_size = cpu_to_be32(backing_filename_len); 764 header_size += backing_filename_len; 765 } else { 766 /* special backing file for vvfat */ 767 backing_file = NULL; 768 } 769 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 770 unmodified sectors */ 771 header.l2_bits = 12; /* 32 KB L2 tables */ 772 } else { 773 header.cluster_bits = 12; /* 4 KB clusters */ 774 header.l2_bits = 9; /* 4 KB L2 tables */ 775 } 776 header_size = (header_size + 7) & ~7; 777 shift = header.cluster_bits + header.l2_bits; 778 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 779 780 header.l1_table_offset = cpu_to_be64(header_size); 781 if (flags & BLOCK_FLAG_ENCRYPT) { 782 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 783 } else { 784 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 785 } 786 787 /* write all the data */ 788 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 789 if (ret != sizeof(header)) { 790 goto exit; 791 } 792 793 if (backing_file) { 794 ret = bdrv_pwrite(qcow_bs, sizeof(header), 795 backing_file, backing_filename_len); 796 if (ret != backing_filename_len) { 797 goto exit; 798 } 799 } 800 801 tmp = g_malloc0(BDRV_SECTOR_SIZE); 802 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 803 BDRV_SECTOR_SIZE); i++) { 804 ret = bdrv_pwrite(qcow_bs, header_size + 805 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 806 if (ret != BDRV_SECTOR_SIZE) { 807 g_free(tmp); 808 goto exit; 809 } 810 } 811 812 g_free(tmp); 813 ret = 0; 814 exit: 815 bdrv_unref(qcow_bs); 816 cleanup: 817 g_free(backing_file); 818 return ret; 819 } 820 821 static int qcow_make_empty(BlockDriverState *bs) 822 { 823 BDRVQcowState *s = bs->opaque; 824 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 825 int ret; 826 827 memset(s->l1_table, 0, l1_length); 828 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 829 l1_length) < 0) 830 return -1; 831 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 832 if (ret < 0) 833 return ret; 834 835 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 836 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 837 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 838 839 return 0; 840 } 841 842 /* XXX: put compressed sectors first, then all the cluster aligned 843 tables to avoid losing bytes in alignment */ 844 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 845 const uint8_t *buf, int nb_sectors) 846 { 847 BDRVQcowState *s = bs->opaque; 848 z_stream strm; 849 int ret, out_len; 850 uint8_t *out_buf; 851 uint64_t cluster_offset; 852 853 if (nb_sectors != s->cluster_sectors) { 854 ret = -EINVAL; 855 856 /* Zero-pad last write if image size is not cluster aligned */ 857 if (sector_num + nb_sectors == bs->total_sectors && 858 nb_sectors < s->cluster_sectors) { 859 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 860 memset(pad_buf, 0, s->cluster_size); 861 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 862 ret = qcow_write_compressed(bs, sector_num, 863 pad_buf, s->cluster_sectors); 864 qemu_vfree(pad_buf); 865 } 866 return ret; 867 } 868 869 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 870 871 /* best compression, small window, no zlib header */ 872 memset(&strm, 0, sizeof(strm)); 873 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 874 Z_DEFLATED, -12, 875 9, Z_DEFAULT_STRATEGY); 876 if (ret != 0) { 877 ret = -EINVAL; 878 goto fail; 879 } 880 881 strm.avail_in = s->cluster_size; 882 strm.next_in = (uint8_t *)buf; 883 strm.avail_out = s->cluster_size; 884 strm.next_out = out_buf; 885 886 ret = deflate(&strm, Z_FINISH); 887 if (ret != Z_STREAM_END && ret != Z_OK) { 888 deflateEnd(&strm); 889 ret = -EINVAL; 890 goto fail; 891 } 892 out_len = strm.next_out - out_buf; 893 894 deflateEnd(&strm); 895 896 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 897 /* could not compress: write normal cluster */ 898 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 899 if (ret < 0) { 900 goto fail; 901 } 902 } else { 903 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 904 out_len, 0, 0); 905 if (cluster_offset == 0) { 906 ret = -EIO; 907 goto fail; 908 } 909 910 cluster_offset &= s->cluster_offset_mask; 911 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 912 if (ret < 0) { 913 goto fail; 914 } 915 } 916 917 ret = 0; 918 fail: 919 g_free(out_buf); 920 return ret; 921 } 922 923 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 924 { 925 BDRVQcowState *s = bs->opaque; 926 bdi->cluster_size = s->cluster_size; 927 return 0; 928 } 929 930 static QemuOptsList qcow_create_opts = { 931 .name = "qcow-create-opts", 932 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 933 .desc = { 934 { 935 .name = BLOCK_OPT_SIZE, 936 .type = QEMU_OPT_SIZE, 937 .help = "Virtual disk size" 938 }, 939 { 940 .name = BLOCK_OPT_BACKING_FILE, 941 .type = QEMU_OPT_STRING, 942 .help = "File name of a base image" 943 }, 944 { 945 .name = BLOCK_OPT_ENCRYPT, 946 .type = QEMU_OPT_BOOL, 947 .help = "Encrypt the image", 948 .def_value_str = "off" 949 }, 950 { /* end of list */ } 951 } 952 }; 953 954 static BlockDriver bdrv_qcow = { 955 .format_name = "qcow", 956 .instance_size = sizeof(BDRVQcowState), 957 .bdrv_probe = qcow_probe, 958 .bdrv_open = qcow_open, 959 .bdrv_close = qcow_close, 960 .bdrv_reopen_prepare = qcow_reopen_prepare, 961 .bdrv_create = qcow_create, 962 .bdrv_has_zero_init = bdrv_has_zero_init_1, 963 .supports_backing = true, 964 965 .bdrv_co_readv = qcow_co_readv, 966 .bdrv_co_writev = qcow_co_writev, 967 .bdrv_co_get_block_status = qcow_co_get_block_status, 968 969 .bdrv_set_key = qcow_set_key, 970 .bdrv_make_empty = qcow_make_empty, 971 .bdrv_write_compressed = qcow_write_compressed, 972 .bdrv_get_info = qcow_get_info, 973 974 .create_opts = &qcow_create_opts, 975 }; 976 977 static void bdrv_qcow_init(void) 978 { 979 bdrv_register(&bdrv_qcow); 980 } 981 982 block_init(bdrv_qcow_init); 983