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 "qapi/qmp/qerror.h" 29 #include "crypto/cipher.h" 30 #include "migration/migration.h" 31 32 /**************************************************************/ 33 /* QEMU COW block driver with compression and encryption support */ 34 35 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 36 #define QCOW_VERSION 1 37 38 #define QCOW_CRYPT_NONE 0 39 #define QCOW_CRYPT_AES 1 40 41 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 42 43 typedef struct QCowHeader { 44 uint32_t magic; 45 uint32_t version; 46 uint64_t backing_file_offset; 47 uint32_t backing_file_size; 48 uint32_t mtime; 49 uint64_t size; /* in bytes */ 50 uint8_t cluster_bits; 51 uint8_t l2_bits; 52 uint16_t padding; 53 uint32_t crypt_method; 54 uint64_t l1_table_offset; 55 } QEMU_PACKED QCowHeader; 56 57 #define L2_CACHE_SIZE 16 58 59 typedef struct BDRVQcowState { 60 int cluster_bits; 61 int cluster_size; 62 int cluster_sectors; 63 int l2_bits; 64 int l2_size; 65 unsigned int l1_size; 66 uint64_t cluster_offset_mask; 67 uint64_t l1_table_offset; 68 uint64_t *l1_table; 69 uint64_t *l2_cache; 70 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 71 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 72 uint8_t *cluster_cache; 73 uint8_t *cluster_data; 74 uint64_t cluster_cache_offset; 75 QCryptoCipher *cipher; /* NULL if no key yet */ 76 uint32_t crypt_method_header; 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 unsigned int len, i, shift; 100 int ret; 101 QCowHeader header; 102 103 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 104 if (ret < 0) { 105 goto fail; 106 } 107 be32_to_cpus(&header.magic); 108 be32_to_cpus(&header.version); 109 be64_to_cpus(&header.backing_file_offset); 110 be32_to_cpus(&header.backing_file_size); 111 be32_to_cpus(&header.mtime); 112 be64_to_cpus(&header.size); 113 be32_to_cpus(&header.crypt_method); 114 be64_to_cpus(&header.l1_table_offset); 115 116 if (header.magic != QCOW_MAGIC) { 117 error_setg(errp, "Image not in qcow format"); 118 ret = -EINVAL; 119 goto fail; 120 } 121 if (header.version != QCOW_VERSION) { 122 char version[64]; 123 snprintf(version, sizeof(version), "QCOW version %" PRIu32, 124 header.version); 125 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 126 bdrv_get_device_or_node_name(bs), "qcow", version); 127 ret = -ENOTSUP; 128 goto fail; 129 } 130 131 if (header.size <= 1) { 132 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 133 ret = -EINVAL; 134 goto fail; 135 } 136 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 137 error_setg(errp, "Cluster size must be between 512 and 64k"); 138 ret = -EINVAL; 139 goto fail; 140 } 141 142 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 143 * so bytes = num_entries << 3. */ 144 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 145 error_setg(errp, "L2 table size must be between 512 and 64k"); 146 ret = -EINVAL; 147 goto fail; 148 } 149 150 if (header.crypt_method > QCOW_CRYPT_AES) { 151 error_setg(errp, "invalid encryption method in qcow header"); 152 ret = -EINVAL; 153 goto fail; 154 } 155 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 156 error_setg(errp, "AES cipher not available"); 157 ret = -EINVAL; 158 goto fail; 159 } 160 s->crypt_method_header = header.crypt_method; 161 if (s->crypt_method_header) { 162 bs->encrypted = 1; 163 } 164 s->cluster_bits = header.cluster_bits; 165 s->cluster_size = 1 << s->cluster_bits; 166 s->cluster_sectors = 1 << (s->cluster_bits - 9); 167 s->l2_bits = header.l2_bits; 168 s->l2_size = 1 << s->l2_bits; 169 bs->total_sectors = header.size / 512; 170 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 171 172 /* read the level 1 table */ 173 shift = s->cluster_bits + s->l2_bits; 174 if (header.size > UINT64_MAX - (1LL << shift)) { 175 error_setg(errp, "Image too large"); 176 ret = -EINVAL; 177 goto fail; 178 } else { 179 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 180 if (l1_size > INT_MAX / sizeof(uint64_t)) { 181 error_setg(errp, "Image too large"); 182 ret = -EINVAL; 183 goto fail; 184 } 185 s->l1_size = l1_size; 186 } 187 188 s->l1_table_offset = header.l1_table_offset; 189 s->l1_table = g_try_new(uint64_t, s->l1_size); 190 if (s->l1_table == NULL) { 191 error_setg(errp, "Could not allocate memory for L1 table"); 192 ret = -ENOMEM; 193 goto fail; 194 } 195 196 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 197 s->l1_size * sizeof(uint64_t)); 198 if (ret < 0) { 199 goto fail; 200 } 201 202 for(i = 0;i < s->l1_size; i++) { 203 be64_to_cpus(&s->l1_table[i]); 204 } 205 206 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 207 s->l2_cache = 208 qemu_try_blockalign(bs->file, 209 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 210 if (s->l2_cache == NULL) { 211 error_setg(errp, "Could not allocate L2 table cache"); 212 ret = -ENOMEM; 213 goto fail; 214 } 215 s->cluster_cache = g_malloc(s->cluster_size); 216 s->cluster_data = g_malloc(s->cluster_size); 217 s->cluster_cache_offset = -1; 218 219 /* read the backing file name */ 220 if (header.backing_file_offset != 0) { 221 len = header.backing_file_size; 222 if (len > 1023 || len >= sizeof(bs->backing_file)) { 223 error_setg(errp, "Backing file name too long"); 224 ret = -EINVAL; 225 goto fail; 226 } 227 ret = bdrv_pread(bs->file, header.backing_file_offset, 228 bs->backing_file, len); 229 if (ret < 0) { 230 goto fail; 231 } 232 bs->backing_file[len] = '\0'; 233 } 234 235 /* Disable migration when qcow images are used */ 236 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 237 "does not support live migration", 238 bdrv_get_device_or_node_name(bs)); 239 migrate_add_blocker(s->migration_blocker); 240 241 qemu_co_mutex_init(&s->lock); 242 return 0; 243 244 fail: 245 g_free(s->l1_table); 246 qemu_vfree(s->l2_cache); 247 g_free(s->cluster_cache); 248 g_free(s->cluster_data); 249 return ret; 250 } 251 252 253 /* We have nothing to do for QCOW reopen, stubs just return 254 * success */ 255 static int qcow_reopen_prepare(BDRVReopenState *state, 256 BlockReopenQueue *queue, Error **errp) 257 { 258 return 0; 259 } 260 261 static int qcow_set_key(BlockDriverState *bs, const char *key) 262 { 263 BDRVQcowState *s = bs->opaque; 264 uint8_t keybuf[16]; 265 int len, i; 266 Error *err; 267 268 memset(keybuf, 0, 16); 269 len = strlen(key); 270 if (len > 16) 271 len = 16; 272 /* XXX: we could compress the chars to 7 bits to increase 273 entropy */ 274 for(i = 0;i < len;i++) { 275 keybuf[i] = key[i]; 276 } 277 assert(bs->encrypted); 278 279 qcrypto_cipher_free(s->cipher); 280 s->cipher = qcrypto_cipher_new( 281 QCRYPTO_CIPHER_ALG_AES_128, 282 QCRYPTO_CIPHER_MODE_CBC, 283 keybuf, G_N_ELEMENTS(keybuf), 284 &err); 285 286 if (!s->cipher) { 287 /* XXX would be nice if errors in this method could 288 * be properly propagate to the caller. Would need 289 * the bdrv_set_key() API signature to be fixed. */ 290 error_free(err); 291 return -1; 292 } 293 return 0; 294 } 295 296 /* The crypt function is compatible with the linux cryptoloop 297 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 298 supported */ 299 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 300 uint8_t *out_buf, const uint8_t *in_buf, 301 int nb_sectors, bool enc, Error **errp) 302 { 303 union { 304 uint64_t ll[2]; 305 uint8_t b[16]; 306 } ivec; 307 int i; 308 int ret; 309 310 for(i = 0; i < nb_sectors; i++) { 311 ivec.ll[0] = cpu_to_le64(sector_num); 312 ivec.ll[1] = 0; 313 if (qcrypto_cipher_setiv(s->cipher, 314 ivec.b, G_N_ELEMENTS(ivec.b), 315 errp) < 0) { 316 return -1; 317 } 318 if (enc) { 319 ret = qcrypto_cipher_encrypt(s->cipher, 320 in_buf, 321 out_buf, 322 512, 323 errp); 324 } else { 325 ret = qcrypto_cipher_decrypt(s->cipher, 326 in_buf, 327 out_buf, 328 512, 329 errp); 330 } 331 if (ret < 0) { 332 return -1; 333 } 334 sector_num++; 335 in_buf += 512; 336 out_buf += 512; 337 } 338 return 0; 339 } 340 341 /* 'allocate' is: 342 * 343 * 0 to not allocate. 344 * 345 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 346 * 'n_end') 347 * 348 * 2 to allocate a compressed cluster of size 349 * 'compressed_size'. 'compressed_size' must be > 0 and < 350 * cluster_size 351 * 352 * return 0 if not allocated. 353 */ 354 static uint64_t get_cluster_offset(BlockDriverState *bs, 355 uint64_t offset, int allocate, 356 int compressed_size, 357 int n_start, int n_end) 358 { 359 BDRVQcowState *s = bs->opaque; 360 int min_index, i, j, l1_index, l2_index; 361 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 362 uint32_t min_count; 363 int new_l2_table; 364 365 l1_index = offset >> (s->l2_bits + s->cluster_bits); 366 l2_offset = s->l1_table[l1_index]; 367 new_l2_table = 0; 368 if (!l2_offset) { 369 if (!allocate) 370 return 0; 371 /* allocate a new l2 entry */ 372 l2_offset = bdrv_getlength(bs->file); 373 /* round to cluster size */ 374 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 375 /* update the L1 entry */ 376 s->l1_table[l1_index] = l2_offset; 377 tmp = cpu_to_be64(l2_offset); 378 if (bdrv_pwrite_sync(bs->file, 379 s->l1_table_offset + l1_index * sizeof(tmp), 380 &tmp, sizeof(tmp)) < 0) 381 return 0; 382 new_l2_table = 1; 383 } 384 for(i = 0; i < L2_CACHE_SIZE; i++) { 385 if (l2_offset == s->l2_cache_offsets[i]) { 386 /* increment the hit count */ 387 if (++s->l2_cache_counts[i] == 0xffffffff) { 388 for(j = 0; j < L2_CACHE_SIZE; j++) { 389 s->l2_cache_counts[j] >>= 1; 390 } 391 } 392 l2_table = s->l2_cache + (i << s->l2_bits); 393 goto found; 394 } 395 } 396 /* not found: load a new entry in the least used one */ 397 min_index = 0; 398 min_count = 0xffffffff; 399 for(i = 0; i < L2_CACHE_SIZE; i++) { 400 if (s->l2_cache_counts[i] < min_count) { 401 min_count = s->l2_cache_counts[i]; 402 min_index = i; 403 } 404 } 405 l2_table = s->l2_cache + (min_index << s->l2_bits); 406 if (new_l2_table) { 407 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 408 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 409 s->l2_size * sizeof(uint64_t)) < 0) 410 return 0; 411 } else { 412 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 413 s->l2_size * sizeof(uint64_t)) 414 return 0; 415 } 416 s->l2_cache_offsets[min_index] = l2_offset; 417 s->l2_cache_counts[min_index] = 1; 418 found: 419 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 420 cluster_offset = be64_to_cpu(l2_table[l2_index]); 421 if (!cluster_offset || 422 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 423 if (!allocate) 424 return 0; 425 /* allocate a new cluster */ 426 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 427 (n_end - n_start) < s->cluster_sectors) { 428 /* if the cluster is already compressed, we must 429 decompress it in the case it is not completely 430 overwritten */ 431 if (decompress_cluster(bs, cluster_offset) < 0) 432 return 0; 433 cluster_offset = bdrv_getlength(bs->file); 434 cluster_offset = (cluster_offset + s->cluster_size - 1) & 435 ~(s->cluster_size - 1); 436 /* write the cluster content */ 437 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 438 s->cluster_size) 439 return -1; 440 } else { 441 cluster_offset = bdrv_getlength(bs->file); 442 if (allocate == 1) { 443 /* round to cluster size */ 444 cluster_offset = (cluster_offset + s->cluster_size - 1) & 445 ~(s->cluster_size - 1); 446 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 447 /* if encrypted, we must initialize the cluster 448 content which won't be written */ 449 if (bs->encrypted && 450 (n_end - n_start) < s->cluster_sectors) { 451 uint64_t start_sect; 452 assert(s->cipher); 453 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 454 memset(s->cluster_data + 512, 0x00, 512); 455 for(i = 0; i < s->cluster_sectors; i++) { 456 if (i < n_start || i >= n_end) { 457 Error *err = NULL; 458 if (encrypt_sectors(s, start_sect + i, 459 s->cluster_data, 460 s->cluster_data + 512, 1, 461 true, &err) < 0) { 462 error_free(err); 463 errno = EIO; 464 return -1; 465 } 466 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 467 s->cluster_data, 512) != 512) 468 return -1; 469 } 470 } 471 } 472 } else if (allocate == 2) { 473 cluster_offset |= QCOW_OFLAG_COMPRESSED | 474 (uint64_t)compressed_size << (63 - s->cluster_bits); 475 } 476 } 477 /* update L2 table */ 478 tmp = cpu_to_be64(cluster_offset); 479 l2_table[l2_index] = tmp; 480 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 481 &tmp, sizeof(tmp)) < 0) 482 return 0; 483 } 484 return cluster_offset; 485 } 486 487 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 488 int64_t sector_num, int nb_sectors, int *pnum) 489 { 490 BDRVQcowState *s = bs->opaque; 491 int index_in_cluster, n; 492 uint64_t cluster_offset; 493 494 qemu_co_mutex_lock(&s->lock); 495 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 496 qemu_co_mutex_unlock(&s->lock); 497 index_in_cluster = sector_num & (s->cluster_sectors - 1); 498 n = s->cluster_sectors - index_in_cluster; 499 if (n > nb_sectors) 500 n = nb_sectors; 501 *pnum = n; 502 if (!cluster_offset) { 503 return 0; 504 } 505 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 506 return BDRV_BLOCK_DATA; 507 } 508 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 509 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 510 } 511 512 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 513 const uint8_t *buf, int buf_size) 514 { 515 z_stream strm1, *strm = &strm1; 516 int ret, out_len; 517 518 memset(strm, 0, sizeof(*strm)); 519 520 strm->next_in = (uint8_t *)buf; 521 strm->avail_in = buf_size; 522 strm->next_out = out_buf; 523 strm->avail_out = out_buf_size; 524 525 ret = inflateInit2(strm, -12); 526 if (ret != Z_OK) 527 return -1; 528 ret = inflate(strm, Z_FINISH); 529 out_len = strm->next_out - out_buf; 530 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 531 out_len != out_buf_size) { 532 inflateEnd(strm); 533 return -1; 534 } 535 inflateEnd(strm); 536 return 0; 537 } 538 539 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 540 { 541 BDRVQcowState *s = bs->opaque; 542 int ret, csize; 543 uint64_t coffset; 544 545 coffset = cluster_offset & s->cluster_offset_mask; 546 if (s->cluster_cache_offset != coffset) { 547 csize = cluster_offset >> (63 - s->cluster_bits); 548 csize &= (s->cluster_size - 1); 549 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 550 if (ret != csize) 551 return -1; 552 if (decompress_buffer(s->cluster_cache, s->cluster_size, 553 s->cluster_data, csize) < 0) { 554 return -1; 555 } 556 s->cluster_cache_offset = coffset; 557 } 558 return 0; 559 } 560 561 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 562 int nb_sectors, QEMUIOVector *qiov) 563 { 564 BDRVQcowState *s = bs->opaque; 565 int index_in_cluster; 566 int ret = 0, n; 567 uint64_t cluster_offset; 568 struct iovec hd_iov; 569 QEMUIOVector hd_qiov; 570 uint8_t *buf; 571 void *orig_buf; 572 Error *err = NULL; 573 574 if (qiov->niov > 1) { 575 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 576 if (buf == NULL) { 577 return -ENOMEM; 578 } 579 } else { 580 orig_buf = NULL; 581 buf = (uint8_t *)qiov->iov->iov_base; 582 } 583 584 qemu_co_mutex_lock(&s->lock); 585 586 while (nb_sectors != 0) { 587 /* prepare next request */ 588 cluster_offset = get_cluster_offset(bs, sector_num << 9, 589 0, 0, 0, 0); 590 index_in_cluster = sector_num & (s->cluster_sectors - 1); 591 n = s->cluster_sectors - index_in_cluster; 592 if (n > nb_sectors) { 593 n = nb_sectors; 594 } 595 596 if (!cluster_offset) { 597 if (bs->backing_hd) { 598 /* read from the base image */ 599 hd_iov.iov_base = (void *)buf; 600 hd_iov.iov_len = n * 512; 601 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 602 qemu_co_mutex_unlock(&s->lock); 603 ret = bdrv_co_readv(bs->backing_hd, sector_num, 604 n, &hd_qiov); 605 qemu_co_mutex_lock(&s->lock); 606 if (ret < 0) { 607 goto fail; 608 } 609 } else { 610 /* Note: in this case, no need to wait */ 611 memset(buf, 0, 512 * n); 612 } 613 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 614 /* add AIO support for compressed blocks ? */ 615 if (decompress_cluster(bs, cluster_offset) < 0) { 616 goto fail; 617 } 618 memcpy(buf, 619 s->cluster_cache + index_in_cluster * 512, 512 * n); 620 } else { 621 if ((cluster_offset & 511) != 0) { 622 goto fail; 623 } 624 hd_iov.iov_base = (void *)buf; 625 hd_iov.iov_len = n * 512; 626 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 627 qemu_co_mutex_unlock(&s->lock); 628 ret = bdrv_co_readv(bs->file, 629 (cluster_offset >> 9) + index_in_cluster, 630 n, &hd_qiov); 631 qemu_co_mutex_lock(&s->lock); 632 if (ret < 0) { 633 break; 634 } 635 if (bs->encrypted) { 636 assert(s->cipher); 637 if (encrypt_sectors(s, sector_num, buf, buf, 638 n, false, &err) < 0) { 639 goto fail; 640 } 641 } 642 } 643 ret = 0; 644 645 nb_sectors -= n; 646 sector_num += n; 647 buf += n * 512; 648 } 649 650 done: 651 qemu_co_mutex_unlock(&s->lock); 652 653 if (qiov->niov > 1) { 654 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 655 qemu_vfree(orig_buf); 656 } 657 658 return ret; 659 660 fail: 661 error_free(err); 662 ret = -EIO; 663 goto done; 664 } 665 666 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 667 int nb_sectors, QEMUIOVector *qiov) 668 { 669 BDRVQcowState *s = bs->opaque; 670 int index_in_cluster; 671 uint64_t cluster_offset; 672 const uint8_t *src_buf; 673 int ret = 0, n; 674 uint8_t *cluster_data = NULL; 675 struct iovec hd_iov; 676 QEMUIOVector hd_qiov; 677 uint8_t *buf; 678 void *orig_buf; 679 680 s->cluster_cache_offset = -1; /* disable compressed cache */ 681 682 if (qiov->niov > 1) { 683 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 684 if (buf == NULL) { 685 return -ENOMEM; 686 } 687 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 688 } else { 689 orig_buf = NULL; 690 buf = (uint8_t *)qiov->iov->iov_base; 691 } 692 693 qemu_co_mutex_lock(&s->lock); 694 695 while (nb_sectors != 0) { 696 697 index_in_cluster = sector_num & (s->cluster_sectors - 1); 698 n = s->cluster_sectors - index_in_cluster; 699 if (n > nb_sectors) { 700 n = nb_sectors; 701 } 702 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 703 index_in_cluster, 704 index_in_cluster + n); 705 if (!cluster_offset || (cluster_offset & 511) != 0) { 706 ret = -EIO; 707 break; 708 } 709 if (bs->encrypted) { 710 Error *err = NULL; 711 assert(s->cipher); 712 if (!cluster_data) { 713 cluster_data = g_malloc0(s->cluster_size); 714 } 715 if (encrypt_sectors(s, sector_num, cluster_data, buf, 716 n, true, &err) < 0) { 717 error_free(err); 718 ret = -EIO; 719 break; 720 } 721 src_buf = cluster_data; 722 } else { 723 src_buf = buf; 724 } 725 726 hd_iov.iov_base = (void *)src_buf; 727 hd_iov.iov_len = n * 512; 728 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 729 qemu_co_mutex_unlock(&s->lock); 730 ret = bdrv_co_writev(bs->file, 731 (cluster_offset >> 9) + index_in_cluster, 732 n, &hd_qiov); 733 qemu_co_mutex_lock(&s->lock); 734 if (ret < 0) { 735 break; 736 } 737 ret = 0; 738 739 nb_sectors -= n; 740 sector_num += n; 741 buf += n * 512; 742 } 743 qemu_co_mutex_unlock(&s->lock); 744 745 if (qiov->niov > 1) { 746 qemu_vfree(orig_buf); 747 } 748 g_free(cluster_data); 749 750 return ret; 751 } 752 753 static void qcow_close(BlockDriverState *bs) 754 { 755 BDRVQcowState *s = bs->opaque; 756 757 qcrypto_cipher_free(s->cipher); 758 s->cipher = NULL; 759 g_free(s->l1_table); 760 qemu_vfree(s->l2_cache); 761 g_free(s->cluster_cache); 762 g_free(s->cluster_data); 763 764 migrate_del_blocker(s->migration_blocker); 765 error_free(s->migration_blocker); 766 } 767 768 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 769 { 770 int header_size, backing_filename_len, l1_size, shift, i; 771 QCowHeader header; 772 uint8_t *tmp; 773 int64_t total_size = 0; 774 char *backing_file = NULL; 775 int flags = 0; 776 Error *local_err = NULL; 777 int ret; 778 BlockDriverState *qcow_bs; 779 780 /* Read out options */ 781 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 782 BDRV_SECTOR_SIZE); 783 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 784 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 785 flags |= BLOCK_FLAG_ENCRYPT; 786 } 787 788 ret = bdrv_create_file(filename, opts, &local_err); 789 if (ret < 0) { 790 error_propagate(errp, local_err); 791 goto cleanup; 792 } 793 794 qcow_bs = NULL; 795 ret = bdrv_open(&qcow_bs, filename, NULL, NULL, 796 BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err); 797 if (ret < 0) { 798 error_propagate(errp, local_err); 799 goto cleanup; 800 } 801 802 ret = bdrv_truncate(qcow_bs, 0); 803 if (ret < 0) { 804 goto exit; 805 } 806 807 memset(&header, 0, sizeof(header)); 808 header.magic = cpu_to_be32(QCOW_MAGIC); 809 header.version = cpu_to_be32(QCOW_VERSION); 810 header.size = cpu_to_be64(total_size); 811 header_size = sizeof(header); 812 backing_filename_len = 0; 813 if (backing_file) { 814 if (strcmp(backing_file, "fat:")) { 815 header.backing_file_offset = cpu_to_be64(header_size); 816 backing_filename_len = strlen(backing_file); 817 header.backing_file_size = cpu_to_be32(backing_filename_len); 818 header_size += backing_filename_len; 819 } else { 820 /* special backing file for vvfat */ 821 backing_file = NULL; 822 } 823 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 824 unmodified sectors */ 825 header.l2_bits = 12; /* 32 KB L2 tables */ 826 } else { 827 header.cluster_bits = 12; /* 4 KB clusters */ 828 header.l2_bits = 9; /* 4 KB L2 tables */ 829 } 830 header_size = (header_size + 7) & ~7; 831 shift = header.cluster_bits + header.l2_bits; 832 l1_size = (total_size + (1LL << shift) - 1) >> shift; 833 834 header.l1_table_offset = cpu_to_be64(header_size); 835 if (flags & BLOCK_FLAG_ENCRYPT) { 836 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 837 } else { 838 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 839 } 840 841 /* write all the data */ 842 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 843 if (ret != sizeof(header)) { 844 goto exit; 845 } 846 847 if (backing_file) { 848 ret = bdrv_pwrite(qcow_bs, sizeof(header), 849 backing_file, backing_filename_len); 850 if (ret != backing_filename_len) { 851 goto exit; 852 } 853 } 854 855 tmp = g_malloc0(BDRV_SECTOR_SIZE); 856 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 857 BDRV_SECTOR_SIZE); i++) { 858 ret = bdrv_pwrite(qcow_bs, header_size + 859 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 860 if (ret != BDRV_SECTOR_SIZE) { 861 g_free(tmp); 862 goto exit; 863 } 864 } 865 866 g_free(tmp); 867 ret = 0; 868 exit: 869 bdrv_unref(qcow_bs); 870 cleanup: 871 g_free(backing_file); 872 return ret; 873 } 874 875 static int qcow_make_empty(BlockDriverState *bs) 876 { 877 BDRVQcowState *s = bs->opaque; 878 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 879 int ret; 880 881 memset(s->l1_table, 0, l1_length); 882 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 883 l1_length) < 0) 884 return -1; 885 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 886 if (ret < 0) 887 return ret; 888 889 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 890 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 891 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 892 893 return 0; 894 } 895 896 /* XXX: put compressed sectors first, then all the cluster aligned 897 tables to avoid losing bytes in alignment */ 898 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 899 const uint8_t *buf, int nb_sectors) 900 { 901 BDRVQcowState *s = bs->opaque; 902 z_stream strm; 903 int ret, out_len; 904 uint8_t *out_buf; 905 uint64_t cluster_offset; 906 907 if (nb_sectors != s->cluster_sectors) { 908 ret = -EINVAL; 909 910 /* Zero-pad last write if image size is not cluster aligned */ 911 if (sector_num + nb_sectors == bs->total_sectors && 912 nb_sectors < s->cluster_sectors) { 913 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 914 memset(pad_buf, 0, s->cluster_size); 915 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 916 ret = qcow_write_compressed(bs, sector_num, 917 pad_buf, s->cluster_sectors); 918 qemu_vfree(pad_buf); 919 } 920 return ret; 921 } 922 923 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 924 925 /* best compression, small window, no zlib header */ 926 memset(&strm, 0, sizeof(strm)); 927 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 928 Z_DEFLATED, -12, 929 9, Z_DEFAULT_STRATEGY); 930 if (ret != 0) { 931 ret = -EINVAL; 932 goto fail; 933 } 934 935 strm.avail_in = s->cluster_size; 936 strm.next_in = (uint8_t *)buf; 937 strm.avail_out = s->cluster_size; 938 strm.next_out = out_buf; 939 940 ret = deflate(&strm, Z_FINISH); 941 if (ret != Z_STREAM_END && ret != Z_OK) { 942 deflateEnd(&strm); 943 ret = -EINVAL; 944 goto fail; 945 } 946 out_len = strm.next_out - out_buf; 947 948 deflateEnd(&strm); 949 950 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 951 /* could not compress: write normal cluster */ 952 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 953 if (ret < 0) { 954 goto fail; 955 } 956 } else { 957 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 958 out_len, 0, 0); 959 if (cluster_offset == 0) { 960 ret = -EIO; 961 goto fail; 962 } 963 964 cluster_offset &= s->cluster_offset_mask; 965 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 966 if (ret < 0) { 967 goto fail; 968 } 969 } 970 971 ret = 0; 972 fail: 973 g_free(out_buf); 974 return ret; 975 } 976 977 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 978 { 979 BDRVQcowState *s = bs->opaque; 980 bdi->cluster_size = s->cluster_size; 981 return 0; 982 } 983 984 static QemuOptsList qcow_create_opts = { 985 .name = "qcow-create-opts", 986 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 987 .desc = { 988 { 989 .name = BLOCK_OPT_SIZE, 990 .type = QEMU_OPT_SIZE, 991 .help = "Virtual disk size" 992 }, 993 { 994 .name = BLOCK_OPT_BACKING_FILE, 995 .type = QEMU_OPT_STRING, 996 .help = "File name of a base image" 997 }, 998 { 999 .name = BLOCK_OPT_ENCRYPT, 1000 .type = QEMU_OPT_BOOL, 1001 .help = "Encrypt the image", 1002 .def_value_str = "off" 1003 }, 1004 { /* end of list */ } 1005 } 1006 }; 1007 1008 static BlockDriver bdrv_qcow = { 1009 .format_name = "qcow", 1010 .instance_size = sizeof(BDRVQcowState), 1011 .bdrv_probe = qcow_probe, 1012 .bdrv_open = qcow_open, 1013 .bdrv_close = qcow_close, 1014 .bdrv_reopen_prepare = qcow_reopen_prepare, 1015 .bdrv_create = qcow_create, 1016 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1017 .supports_backing = true, 1018 1019 .bdrv_co_readv = qcow_co_readv, 1020 .bdrv_co_writev = qcow_co_writev, 1021 .bdrv_co_get_block_status = qcow_co_get_block_status, 1022 1023 .bdrv_set_key = qcow_set_key, 1024 .bdrv_make_empty = qcow_make_empty, 1025 .bdrv_write_compressed = qcow_write_compressed, 1026 .bdrv_get_info = qcow_get_info, 1027 1028 .create_opts = &qcow_create_opts, 1029 }; 1030 1031 static void bdrv_qcow_init(void) 1032 { 1033 bdrv_register(&bdrv_qcow); 1034 } 1035 1036 block_init(bdrv_qcow_init); 1037