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 bdrv_get_device_or_node_name(bs), "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 || len >= sizeof(bs->backing_file)) { 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_setg(&s->migration_blocker, "The qcow format used by node '%s' " 233 "does not support live migration", 234 bdrv_get_device_or_node_name(bs)); 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 assert(bs->encrypted); 273 s->crypt_method = s->crypt_method_header; 274 275 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 276 return -1; 277 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 278 return -1; 279 return 0; 280 } 281 282 /* The crypt function is compatible with the linux cryptoloop 283 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 284 supported */ 285 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 286 uint8_t *out_buf, const uint8_t *in_buf, 287 int nb_sectors, int enc, 288 const AES_KEY *key) 289 { 290 union { 291 uint64_t ll[2]; 292 uint8_t b[16]; 293 } ivec; 294 int i; 295 296 for(i = 0; i < nb_sectors; i++) { 297 ivec.ll[0] = cpu_to_le64(sector_num); 298 ivec.ll[1] = 0; 299 AES_cbc_encrypt(in_buf, out_buf, 512, key, 300 ivec.b, enc); 301 sector_num++; 302 in_buf += 512; 303 out_buf += 512; 304 } 305 } 306 307 /* 'allocate' is: 308 * 309 * 0 to not allocate. 310 * 311 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 312 * 'n_end') 313 * 314 * 2 to allocate a compressed cluster of size 315 * 'compressed_size'. 'compressed_size' must be > 0 and < 316 * cluster_size 317 * 318 * return 0 if not allocated. 319 */ 320 static uint64_t get_cluster_offset(BlockDriverState *bs, 321 uint64_t offset, int allocate, 322 int compressed_size, 323 int n_start, int n_end) 324 { 325 BDRVQcowState *s = bs->opaque; 326 int min_index, i, j, l1_index, l2_index; 327 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 328 uint32_t min_count; 329 int new_l2_table; 330 331 l1_index = offset >> (s->l2_bits + s->cluster_bits); 332 l2_offset = s->l1_table[l1_index]; 333 new_l2_table = 0; 334 if (!l2_offset) { 335 if (!allocate) 336 return 0; 337 /* allocate a new l2 entry */ 338 l2_offset = bdrv_getlength(bs->file); 339 /* round to cluster size */ 340 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 341 /* update the L1 entry */ 342 s->l1_table[l1_index] = l2_offset; 343 tmp = cpu_to_be64(l2_offset); 344 if (bdrv_pwrite_sync(bs->file, 345 s->l1_table_offset + l1_index * sizeof(tmp), 346 &tmp, sizeof(tmp)) < 0) 347 return 0; 348 new_l2_table = 1; 349 } 350 for(i = 0; i < L2_CACHE_SIZE; i++) { 351 if (l2_offset == s->l2_cache_offsets[i]) { 352 /* increment the hit count */ 353 if (++s->l2_cache_counts[i] == 0xffffffff) { 354 for(j = 0; j < L2_CACHE_SIZE; j++) { 355 s->l2_cache_counts[j] >>= 1; 356 } 357 } 358 l2_table = s->l2_cache + (i << s->l2_bits); 359 goto found; 360 } 361 } 362 /* not found: load a new entry in the least used one */ 363 min_index = 0; 364 min_count = 0xffffffff; 365 for(i = 0; i < L2_CACHE_SIZE; i++) { 366 if (s->l2_cache_counts[i] < min_count) { 367 min_count = s->l2_cache_counts[i]; 368 min_index = i; 369 } 370 } 371 l2_table = s->l2_cache + (min_index << s->l2_bits); 372 if (new_l2_table) { 373 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 374 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 375 s->l2_size * sizeof(uint64_t)) < 0) 376 return 0; 377 } else { 378 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 379 s->l2_size * sizeof(uint64_t)) 380 return 0; 381 } 382 s->l2_cache_offsets[min_index] = l2_offset; 383 s->l2_cache_counts[min_index] = 1; 384 found: 385 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 386 cluster_offset = be64_to_cpu(l2_table[l2_index]); 387 if (!cluster_offset || 388 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 389 if (!allocate) 390 return 0; 391 /* allocate a new cluster */ 392 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 393 (n_end - n_start) < s->cluster_sectors) { 394 /* if the cluster is already compressed, we must 395 decompress it in the case it is not completely 396 overwritten */ 397 if (decompress_cluster(bs, cluster_offset) < 0) 398 return 0; 399 cluster_offset = bdrv_getlength(bs->file); 400 cluster_offset = (cluster_offset + s->cluster_size - 1) & 401 ~(s->cluster_size - 1); 402 /* write the cluster content */ 403 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 404 s->cluster_size) 405 return -1; 406 } else { 407 cluster_offset = bdrv_getlength(bs->file); 408 if (allocate == 1) { 409 /* round to cluster size */ 410 cluster_offset = (cluster_offset + s->cluster_size - 1) & 411 ~(s->cluster_size - 1); 412 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 413 /* if encrypted, we must initialize the cluster 414 content which won't be written */ 415 if (bs->encrypted && 416 (n_end - n_start) < s->cluster_sectors) { 417 uint64_t start_sect; 418 assert(s->crypt_method); 419 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 420 memset(s->cluster_data + 512, 0x00, 512); 421 for(i = 0; i < s->cluster_sectors; i++) { 422 if (i < n_start || i >= n_end) { 423 encrypt_sectors(s, start_sect + i, 424 s->cluster_data, 425 s->cluster_data + 512, 1, 1, 426 &s->aes_encrypt_key); 427 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 428 s->cluster_data, 512) != 512) 429 return -1; 430 } 431 } 432 } 433 } else if (allocate == 2) { 434 cluster_offset |= QCOW_OFLAG_COMPRESSED | 435 (uint64_t)compressed_size << (63 - s->cluster_bits); 436 } 437 } 438 /* update L2 table */ 439 tmp = cpu_to_be64(cluster_offset); 440 l2_table[l2_index] = tmp; 441 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 442 &tmp, sizeof(tmp)) < 0) 443 return 0; 444 } 445 return cluster_offset; 446 } 447 448 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 449 int64_t sector_num, int nb_sectors, int *pnum) 450 { 451 BDRVQcowState *s = bs->opaque; 452 int index_in_cluster, n; 453 uint64_t cluster_offset; 454 455 qemu_co_mutex_lock(&s->lock); 456 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 457 qemu_co_mutex_unlock(&s->lock); 458 index_in_cluster = sector_num & (s->cluster_sectors - 1); 459 n = s->cluster_sectors - index_in_cluster; 460 if (n > nb_sectors) 461 n = nb_sectors; 462 *pnum = n; 463 if (!cluster_offset) { 464 return 0; 465 } 466 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) { 467 return BDRV_BLOCK_DATA; 468 } 469 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 470 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 471 } 472 473 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 474 const uint8_t *buf, int buf_size) 475 { 476 z_stream strm1, *strm = &strm1; 477 int ret, out_len; 478 479 memset(strm, 0, sizeof(*strm)); 480 481 strm->next_in = (uint8_t *)buf; 482 strm->avail_in = buf_size; 483 strm->next_out = out_buf; 484 strm->avail_out = out_buf_size; 485 486 ret = inflateInit2(strm, -12); 487 if (ret != Z_OK) 488 return -1; 489 ret = inflate(strm, Z_FINISH); 490 out_len = strm->next_out - out_buf; 491 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 492 out_len != out_buf_size) { 493 inflateEnd(strm); 494 return -1; 495 } 496 inflateEnd(strm); 497 return 0; 498 } 499 500 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 501 { 502 BDRVQcowState *s = bs->opaque; 503 int ret, csize; 504 uint64_t coffset; 505 506 coffset = cluster_offset & s->cluster_offset_mask; 507 if (s->cluster_cache_offset != coffset) { 508 csize = cluster_offset >> (63 - s->cluster_bits); 509 csize &= (s->cluster_size - 1); 510 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 511 if (ret != csize) 512 return -1; 513 if (decompress_buffer(s->cluster_cache, s->cluster_size, 514 s->cluster_data, csize) < 0) { 515 return -1; 516 } 517 s->cluster_cache_offset = coffset; 518 } 519 return 0; 520 } 521 522 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 523 int nb_sectors, QEMUIOVector *qiov) 524 { 525 BDRVQcowState *s = bs->opaque; 526 int index_in_cluster; 527 int ret = 0, n; 528 uint64_t cluster_offset; 529 struct iovec hd_iov; 530 QEMUIOVector hd_qiov; 531 uint8_t *buf; 532 void *orig_buf; 533 534 if (qiov->niov > 1) { 535 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 536 if (buf == NULL) { 537 return -ENOMEM; 538 } 539 } else { 540 orig_buf = NULL; 541 buf = (uint8_t *)qiov->iov->iov_base; 542 } 543 544 qemu_co_mutex_lock(&s->lock); 545 546 while (nb_sectors != 0) { 547 /* prepare next request */ 548 cluster_offset = get_cluster_offset(bs, sector_num << 9, 549 0, 0, 0, 0); 550 index_in_cluster = sector_num & (s->cluster_sectors - 1); 551 n = s->cluster_sectors - index_in_cluster; 552 if (n > nb_sectors) { 553 n = nb_sectors; 554 } 555 556 if (!cluster_offset) { 557 if (bs->backing_hd) { 558 /* read from the base image */ 559 hd_iov.iov_base = (void *)buf; 560 hd_iov.iov_len = n * 512; 561 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 562 qemu_co_mutex_unlock(&s->lock); 563 ret = bdrv_co_readv(bs->backing_hd, sector_num, 564 n, &hd_qiov); 565 qemu_co_mutex_lock(&s->lock); 566 if (ret < 0) { 567 goto fail; 568 } 569 } else { 570 /* Note: in this case, no need to wait */ 571 memset(buf, 0, 512 * n); 572 } 573 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 574 /* add AIO support for compressed blocks ? */ 575 if (decompress_cluster(bs, cluster_offset) < 0) { 576 goto fail; 577 } 578 memcpy(buf, 579 s->cluster_cache + index_in_cluster * 512, 512 * n); 580 } else { 581 if ((cluster_offset & 511) != 0) { 582 goto fail; 583 } 584 hd_iov.iov_base = (void *)buf; 585 hd_iov.iov_len = n * 512; 586 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 587 qemu_co_mutex_unlock(&s->lock); 588 ret = bdrv_co_readv(bs->file, 589 (cluster_offset >> 9) + index_in_cluster, 590 n, &hd_qiov); 591 qemu_co_mutex_lock(&s->lock); 592 if (ret < 0) { 593 break; 594 } 595 if (bs->encrypted) { 596 assert(s->crypt_method); 597 encrypt_sectors(s, sector_num, buf, buf, 598 n, 0, 599 &s->aes_decrypt_key); 600 } 601 } 602 ret = 0; 603 604 nb_sectors -= n; 605 sector_num += n; 606 buf += n * 512; 607 } 608 609 done: 610 qemu_co_mutex_unlock(&s->lock); 611 612 if (qiov->niov > 1) { 613 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 614 qemu_vfree(orig_buf); 615 } 616 617 return ret; 618 619 fail: 620 ret = -EIO; 621 goto done; 622 } 623 624 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 625 int nb_sectors, QEMUIOVector *qiov) 626 { 627 BDRVQcowState *s = bs->opaque; 628 int index_in_cluster; 629 uint64_t cluster_offset; 630 const uint8_t *src_buf; 631 int ret = 0, n; 632 uint8_t *cluster_data = NULL; 633 struct iovec hd_iov; 634 QEMUIOVector hd_qiov; 635 uint8_t *buf; 636 void *orig_buf; 637 638 s->cluster_cache_offset = -1; /* disable compressed cache */ 639 640 if (qiov->niov > 1) { 641 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 642 if (buf == NULL) { 643 return -ENOMEM; 644 } 645 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 646 } else { 647 orig_buf = NULL; 648 buf = (uint8_t *)qiov->iov->iov_base; 649 } 650 651 qemu_co_mutex_lock(&s->lock); 652 653 while (nb_sectors != 0) { 654 655 index_in_cluster = sector_num & (s->cluster_sectors - 1); 656 n = s->cluster_sectors - index_in_cluster; 657 if (n > nb_sectors) { 658 n = nb_sectors; 659 } 660 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 661 index_in_cluster, 662 index_in_cluster + n); 663 if (!cluster_offset || (cluster_offset & 511) != 0) { 664 ret = -EIO; 665 break; 666 } 667 if (bs->encrypted) { 668 assert(s->crypt_method); 669 if (!cluster_data) { 670 cluster_data = g_malloc0(s->cluster_size); 671 } 672 encrypt_sectors(s, sector_num, cluster_data, buf, 673 n, 1, &s->aes_encrypt_key); 674 src_buf = cluster_data; 675 } else { 676 src_buf = buf; 677 } 678 679 hd_iov.iov_base = (void *)src_buf; 680 hd_iov.iov_len = n * 512; 681 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 682 qemu_co_mutex_unlock(&s->lock); 683 ret = bdrv_co_writev(bs->file, 684 (cluster_offset >> 9) + index_in_cluster, 685 n, &hd_qiov); 686 qemu_co_mutex_lock(&s->lock); 687 if (ret < 0) { 688 break; 689 } 690 ret = 0; 691 692 nb_sectors -= n; 693 sector_num += n; 694 buf += n * 512; 695 } 696 qemu_co_mutex_unlock(&s->lock); 697 698 if (qiov->niov > 1) { 699 qemu_vfree(orig_buf); 700 } 701 g_free(cluster_data); 702 703 return ret; 704 } 705 706 static void qcow_close(BlockDriverState *bs) 707 { 708 BDRVQcowState *s = bs->opaque; 709 710 g_free(s->l1_table); 711 qemu_vfree(s->l2_cache); 712 g_free(s->cluster_cache); 713 g_free(s->cluster_data); 714 715 migrate_del_blocker(s->migration_blocker); 716 error_free(s->migration_blocker); 717 } 718 719 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 720 { 721 int header_size, backing_filename_len, l1_size, shift, i; 722 QCowHeader header; 723 uint8_t *tmp; 724 int64_t total_size = 0; 725 char *backing_file = NULL; 726 int flags = 0; 727 Error *local_err = NULL; 728 int ret; 729 BlockDriverState *qcow_bs; 730 731 /* Read out options */ 732 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 733 BDRV_SECTOR_SIZE); 734 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 735 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 736 flags |= BLOCK_FLAG_ENCRYPT; 737 } 738 739 ret = bdrv_create_file(filename, opts, &local_err); 740 if (ret < 0) { 741 error_propagate(errp, local_err); 742 goto cleanup; 743 } 744 745 qcow_bs = NULL; 746 ret = bdrv_open(&qcow_bs, filename, NULL, NULL, 747 BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err); 748 if (ret < 0) { 749 error_propagate(errp, local_err); 750 goto cleanup; 751 } 752 753 ret = bdrv_truncate(qcow_bs, 0); 754 if (ret < 0) { 755 goto exit; 756 } 757 758 memset(&header, 0, sizeof(header)); 759 header.magic = cpu_to_be32(QCOW_MAGIC); 760 header.version = cpu_to_be32(QCOW_VERSION); 761 header.size = cpu_to_be64(total_size); 762 header_size = sizeof(header); 763 backing_filename_len = 0; 764 if (backing_file) { 765 if (strcmp(backing_file, "fat:")) { 766 header.backing_file_offset = cpu_to_be64(header_size); 767 backing_filename_len = strlen(backing_file); 768 header.backing_file_size = cpu_to_be32(backing_filename_len); 769 header_size += backing_filename_len; 770 } else { 771 /* special backing file for vvfat */ 772 backing_file = NULL; 773 } 774 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 775 unmodified sectors */ 776 header.l2_bits = 12; /* 32 KB L2 tables */ 777 } else { 778 header.cluster_bits = 12; /* 4 KB clusters */ 779 header.l2_bits = 9; /* 4 KB L2 tables */ 780 } 781 header_size = (header_size + 7) & ~7; 782 shift = header.cluster_bits + header.l2_bits; 783 l1_size = (total_size + (1LL << shift) - 1) >> shift; 784 785 header.l1_table_offset = cpu_to_be64(header_size); 786 if (flags & BLOCK_FLAG_ENCRYPT) { 787 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 788 } else { 789 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 790 } 791 792 /* write all the data */ 793 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 794 if (ret != sizeof(header)) { 795 goto exit; 796 } 797 798 if (backing_file) { 799 ret = bdrv_pwrite(qcow_bs, sizeof(header), 800 backing_file, backing_filename_len); 801 if (ret != backing_filename_len) { 802 goto exit; 803 } 804 } 805 806 tmp = g_malloc0(BDRV_SECTOR_SIZE); 807 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 808 BDRV_SECTOR_SIZE); i++) { 809 ret = bdrv_pwrite(qcow_bs, header_size + 810 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 811 if (ret != BDRV_SECTOR_SIZE) { 812 g_free(tmp); 813 goto exit; 814 } 815 } 816 817 g_free(tmp); 818 ret = 0; 819 exit: 820 bdrv_unref(qcow_bs); 821 cleanup: 822 g_free(backing_file); 823 return ret; 824 } 825 826 static int qcow_make_empty(BlockDriverState *bs) 827 { 828 BDRVQcowState *s = bs->opaque; 829 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 830 int ret; 831 832 memset(s->l1_table, 0, l1_length); 833 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 834 l1_length) < 0) 835 return -1; 836 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 837 if (ret < 0) 838 return ret; 839 840 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 841 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 842 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 843 844 return 0; 845 } 846 847 /* XXX: put compressed sectors first, then all the cluster aligned 848 tables to avoid losing bytes in alignment */ 849 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 850 const uint8_t *buf, int nb_sectors) 851 { 852 BDRVQcowState *s = bs->opaque; 853 z_stream strm; 854 int ret, out_len; 855 uint8_t *out_buf; 856 uint64_t cluster_offset; 857 858 if (nb_sectors != s->cluster_sectors) { 859 ret = -EINVAL; 860 861 /* Zero-pad last write if image size is not cluster aligned */ 862 if (sector_num + nb_sectors == bs->total_sectors && 863 nb_sectors < s->cluster_sectors) { 864 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 865 memset(pad_buf, 0, s->cluster_size); 866 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 867 ret = qcow_write_compressed(bs, sector_num, 868 pad_buf, s->cluster_sectors); 869 qemu_vfree(pad_buf); 870 } 871 return ret; 872 } 873 874 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 875 876 /* best compression, small window, no zlib header */ 877 memset(&strm, 0, sizeof(strm)); 878 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 879 Z_DEFLATED, -12, 880 9, Z_DEFAULT_STRATEGY); 881 if (ret != 0) { 882 ret = -EINVAL; 883 goto fail; 884 } 885 886 strm.avail_in = s->cluster_size; 887 strm.next_in = (uint8_t *)buf; 888 strm.avail_out = s->cluster_size; 889 strm.next_out = out_buf; 890 891 ret = deflate(&strm, Z_FINISH); 892 if (ret != Z_STREAM_END && ret != Z_OK) { 893 deflateEnd(&strm); 894 ret = -EINVAL; 895 goto fail; 896 } 897 out_len = strm.next_out - out_buf; 898 899 deflateEnd(&strm); 900 901 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 902 /* could not compress: write normal cluster */ 903 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 904 if (ret < 0) { 905 goto fail; 906 } 907 } else { 908 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 909 out_len, 0, 0); 910 if (cluster_offset == 0) { 911 ret = -EIO; 912 goto fail; 913 } 914 915 cluster_offset &= s->cluster_offset_mask; 916 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 917 if (ret < 0) { 918 goto fail; 919 } 920 } 921 922 ret = 0; 923 fail: 924 g_free(out_buf); 925 return ret; 926 } 927 928 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 929 { 930 BDRVQcowState *s = bs->opaque; 931 bdi->cluster_size = s->cluster_size; 932 return 0; 933 } 934 935 static QemuOptsList qcow_create_opts = { 936 .name = "qcow-create-opts", 937 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 938 .desc = { 939 { 940 .name = BLOCK_OPT_SIZE, 941 .type = QEMU_OPT_SIZE, 942 .help = "Virtual disk size" 943 }, 944 { 945 .name = BLOCK_OPT_BACKING_FILE, 946 .type = QEMU_OPT_STRING, 947 .help = "File name of a base image" 948 }, 949 { 950 .name = BLOCK_OPT_ENCRYPT, 951 .type = QEMU_OPT_BOOL, 952 .help = "Encrypt the image", 953 .def_value_str = "off" 954 }, 955 { /* end of list */ } 956 } 957 }; 958 959 static BlockDriver bdrv_qcow = { 960 .format_name = "qcow", 961 .instance_size = sizeof(BDRVQcowState), 962 .bdrv_probe = qcow_probe, 963 .bdrv_open = qcow_open, 964 .bdrv_close = qcow_close, 965 .bdrv_reopen_prepare = qcow_reopen_prepare, 966 .bdrv_create = qcow_create, 967 .bdrv_has_zero_init = bdrv_has_zero_init_1, 968 .supports_backing = true, 969 970 .bdrv_co_readv = qcow_co_readv, 971 .bdrv_co_writev = qcow_co_writev, 972 .bdrv_co_get_block_status = qcow_co_get_block_status, 973 974 .bdrv_set_key = qcow_set_key, 975 .bdrv_make_empty = qcow_make_empty, 976 .bdrv_write_compressed = qcow_write_compressed, 977 .bdrv_get_info = qcow_get_info, 978 979 .create_opts = &qcow_create_opts, 980 }; 981 982 static void bdrv_qcow_init(void) 983 { 984 bdrv_register(&bdrv_qcow); 985 } 986 987 block_init(bdrv_qcow_init); 988