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/osdep.h" 25 #include "qapi/error.h" 26 #include "qemu-common.h" 27 #include "qemu/error-report.h" 28 #include "block/block_int.h" 29 #include "sysemu/block-backend.h" 30 #include "qemu/module.h" 31 #include "qemu/bswap.h" 32 #include <zlib.h> 33 #include "qapi/qmp/qerror.h" 34 #include "crypto/cipher.h" 35 #include "migration/migration.h" 36 37 /**************************************************************/ 38 /* QEMU COW block driver with compression and encryption support */ 39 40 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 41 #define QCOW_VERSION 1 42 43 #define QCOW_CRYPT_NONE 0 44 #define QCOW_CRYPT_AES 1 45 46 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 47 48 typedef struct QCowHeader { 49 uint32_t magic; 50 uint32_t version; 51 uint64_t backing_file_offset; 52 uint32_t backing_file_size; 53 uint32_t mtime; 54 uint64_t size; /* in bytes */ 55 uint8_t cluster_bits; 56 uint8_t l2_bits; 57 uint16_t padding; 58 uint32_t crypt_method; 59 uint64_t l1_table_offset; 60 } QEMU_PACKED QCowHeader; 61 62 #define L2_CACHE_SIZE 16 63 64 typedef struct BDRVQcowState { 65 int cluster_bits; 66 int cluster_size; 67 int cluster_sectors; 68 int l2_bits; 69 int l2_size; 70 unsigned int l1_size; 71 uint64_t cluster_offset_mask; 72 uint64_t l1_table_offset; 73 uint64_t *l1_table; 74 uint64_t *l2_cache; 75 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 76 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 77 uint8_t *cluster_cache; 78 uint8_t *cluster_data; 79 uint64_t cluster_cache_offset; 80 QCryptoCipher *cipher; /* NULL if no key yet */ 81 uint32_t crypt_method_header; 82 CoMutex lock; 83 Error *migration_blocker; 84 } BDRVQcowState; 85 86 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 87 88 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 89 { 90 const QCowHeader *cow_header = (const void *)buf; 91 92 if (buf_size >= sizeof(QCowHeader) && 93 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 94 be32_to_cpu(cow_header->version) == QCOW_VERSION) 95 return 100; 96 else 97 return 0; 98 } 99 100 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 101 Error **errp) 102 { 103 BDRVQcowState *s = bs->opaque; 104 unsigned int len, i, shift; 105 int ret; 106 QCowHeader header; 107 108 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 109 if (ret < 0) { 110 goto fail; 111 } 112 be32_to_cpus(&header.magic); 113 be32_to_cpus(&header.version); 114 be64_to_cpus(&header.backing_file_offset); 115 be32_to_cpus(&header.backing_file_size); 116 be32_to_cpus(&header.mtime); 117 be64_to_cpus(&header.size); 118 be32_to_cpus(&header.crypt_method); 119 be64_to_cpus(&header.l1_table_offset); 120 121 if (header.magic != QCOW_MAGIC) { 122 error_setg(errp, "Image not in qcow format"); 123 ret = -EINVAL; 124 goto fail; 125 } 126 if (header.version != QCOW_VERSION) { 127 error_setg(errp, "Unsupported qcow version %" PRIu32, header.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 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128, 157 QCRYPTO_CIPHER_MODE_CBC)) { 158 error_setg(errp, "AES cipher not available"); 159 ret = -EINVAL; 160 goto fail; 161 } 162 s->crypt_method_header = header.crypt_method; 163 if (s->crypt_method_header) { 164 if (bdrv_uses_whitelist() && 165 s->crypt_method_header == QCOW_CRYPT_AES) { 166 error_setg(errp, 167 "Use of AES-CBC encrypted qcow images is no longer " 168 "supported in system emulators"); 169 error_append_hint(errp, 170 "You can use 'qemu-img convert' to convert your " 171 "image to an alternative supported format, such " 172 "as unencrypted qcow, or raw with the LUKS " 173 "format instead.\n"); 174 ret = -ENOSYS; 175 goto fail; 176 } 177 178 bs->encrypted = true; 179 } 180 s->cluster_bits = header.cluster_bits; 181 s->cluster_size = 1 << s->cluster_bits; 182 s->cluster_sectors = 1 << (s->cluster_bits - 9); 183 s->l2_bits = header.l2_bits; 184 s->l2_size = 1 << s->l2_bits; 185 bs->total_sectors = header.size / 512; 186 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 187 188 /* read the level 1 table */ 189 shift = s->cluster_bits + s->l2_bits; 190 if (header.size > UINT64_MAX - (1LL << shift)) { 191 error_setg(errp, "Image too large"); 192 ret = -EINVAL; 193 goto fail; 194 } else { 195 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 196 if (l1_size > INT_MAX / sizeof(uint64_t)) { 197 error_setg(errp, "Image too large"); 198 ret = -EINVAL; 199 goto fail; 200 } 201 s->l1_size = l1_size; 202 } 203 204 s->l1_table_offset = header.l1_table_offset; 205 s->l1_table = g_try_new(uint64_t, s->l1_size); 206 if (s->l1_table == NULL) { 207 error_setg(errp, "Could not allocate memory for L1 table"); 208 ret = -ENOMEM; 209 goto fail; 210 } 211 212 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 213 s->l1_size * sizeof(uint64_t)); 214 if (ret < 0) { 215 goto fail; 216 } 217 218 for(i = 0;i < s->l1_size; i++) { 219 be64_to_cpus(&s->l1_table[i]); 220 } 221 222 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 223 s->l2_cache = 224 qemu_try_blockalign(bs->file->bs, 225 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 226 if (s->l2_cache == NULL) { 227 error_setg(errp, "Could not allocate L2 table cache"); 228 ret = -ENOMEM; 229 goto fail; 230 } 231 s->cluster_cache = g_malloc(s->cluster_size); 232 s->cluster_data = g_malloc(s->cluster_size); 233 s->cluster_cache_offset = -1; 234 235 /* read the backing file name */ 236 if (header.backing_file_offset != 0) { 237 len = header.backing_file_size; 238 if (len > 1023 || len >= sizeof(bs->backing_file)) { 239 error_setg(errp, "Backing file name too long"); 240 ret = -EINVAL; 241 goto fail; 242 } 243 ret = bdrv_pread(bs->file, header.backing_file_offset, 244 bs->backing_file, len); 245 if (ret < 0) { 246 goto fail; 247 } 248 bs->backing_file[len] = '\0'; 249 } 250 251 /* Disable migration when qcow images are used */ 252 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 253 "does not support live migration", 254 bdrv_get_device_or_node_name(bs)); 255 migrate_add_blocker(s->migration_blocker); 256 257 qemu_co_mutex_init(&s->lock); 258 return 0; 259 260 fail: 261 g_free(s->l1_table); 262 qemu_vfree(s->l2_cache); 263 g_free(s->cluster_cache); 264 g_free(s->cluster_data); 265 return ret; 266 } 267 268 269 /* We have nothing to do for QCOW reopen, stubs just return 270 * success */ 271 static int qcow_reopen_prepare(BDRVReopenState *state, 272 BlockReopenQueue *queue, Error **errp) 273 { 274 return 0; 275 } 276 277 static int qcow_set_key(BlockDriverState *bs, const char *key) 278 { 279 BDRVQcowState *s = bs->opaque; 280 uint8_t keybuf[16]; 281 int len, i; 282 Error *err; 283 284 memset(keybuf, 0, 16); 285 len = strlen(key); 286 if (len > 16) 287 len = 16; 288 /* XXX: we could compress the chars to 7 bits to increase 289 entropy */ 290 for(i = 0;i < len;i++) { 291 keybuf[i] = key[i]; 292 } 293 assert(bs->encrypted); 294 295 qcrypto_cipher_free(s->cipher); 296 s->cipher = qcrypto_cipher_new( 297 QCRYPTO_CIPHER_ALG_AES_128, 298 QCRYPTO_CIPHER_MODE_CBC, 299 keybuf, G_N_ELEMENTS(keybuf), 300 &err); 301 302 if (!s->cipher) { 303 /* XXX would be nice if errors in this method could 304 * be properly propagate to the caller. Would need 305 * the bdrv_set_key() API signature to be fixed. */ 306 error_free(err); 307 return -1; 308 } 309 return 0; 310 } 311 312 /* The crypt function is compatible with the linux cryptoloop 313 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 314 supported */ 315 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 316 uint8_t *out_buf, const uint8_t *in_buf, 317 int nb_sectors, bool enc, Error **errp) 318 { 319 union { 320 uint64_t ll[2]; 321 uint8_t b[16]; 322 } ivec; 323 int i; 324 int ret; 325 326 for(i = 0; i < nb_sectors; i++) { 327 ivec.ll[0] = cpu_to_le64(sector_num); 328 ivec.ll[1] = 0; 329 if (qcrypto_cipher_setiv(s->cipher, 330 ivec.b, G_N_ELEMENTS(ivec.b), 331 errp) < 0) { 332 return -1; 333 } 334 if (enc) { 335 ret = qcrypto_cipher_encrypt(s->cipher, 336 in_buf, 337 out_buf, 338 512, 339 errp); 340 } else { 341 ret = qcrypto_cipher_decrypt(s->cipher, 342 in_buf, 343 out_buf, 344 512, 345 errp); 346 } 347 if (ret < 0) { 348 return -1; 349 } 350 sector_num++; 351 in_buf += 512; 352 out_buf += 512; 353 } 354 return 0; 355 } 356 357 /* 'allocate' is: 358 * 359 * 0 to not allocate. 360 * 361 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 362 * 'n_end') 363 * 364 * 2 to allocate a compressed cluster of size 365 * 'compressed_size'. 'compressed_size' must be > 0 and < 366 * cluster_size 367 * 368 * return 0 if not allocated. 369 */ 370 static uint64_t get_cluster_offset(BlockDriverState *bs, 371 uint64_t offset, int allocate, 372 int compressed_size, 373 int n_start, int n_end) 374 { 375 BDRVQcowState *s = bs->opaque; 376 int min_index, i, j, l1_index, l2_index; 377 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 378 uint32_t min_count; 379 int new_l2_table; 380 381 l1_index = offset >> (s->l2_bits + s->cluster_bits); 382 l2_offset = s->l1_table[l1_index]; 383 new_l2_table = 0; 384 if (!l2_offset) { 385 if (!allocate) 386 return 0; 387 /* allocate a new l2 entry */ 388 l2_offset = bdrv_getlength(bs->file->bs); 389 /* round to cluster size */ 390 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 391 /* update the L1 entry */ 392 s->l1_table[l1_index] = l2_offset; 393 tmp = cpu_to_be64(l2_offset); 394 if (bdrv_pwrite_sync(bs->file, 395 s->l1_table_offset + l1_index * sizeof(tmp), 396 &tmp, sizeof(tmp)) < 0) 397 return 0; 398 new_l2_table = 1; 399 } 400 for(i = 0; i < L2_CACHE_SIZE; i++) { 401 if (l2_offset == s->l2_cache_offsets[i]) { 402 /* increment the hit count */ 403 if (++s->l2_cache_counts[i] == 0xffffffff) { 404 for(j = 0; j < L2_CACHE_SIZE; j++) { 405 s->l2_cache_counts[j] >>= 1; 406 } 407 } 408 l2_table = s->l2_cache + (i << s->l2_bits); 409 goto found; 410 } 411 } 412 /* not found: load a new entry in the least used one */ 413 min_index = 0; 414 min_count = 0xffffffff; 415 for(i = 0; i < L2_CACHE_SIZE; i++) { 416 if (s->l2_cache_counts[i] < min_count) { 417 min_count = s->l2_cache_counts[i]; 418 min_index = i; 419 } 420 } 421 l2_table = s->l2_cache + (min_index << s->l2_bits); 422 if (new_l2_table) { 423 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 424 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 425 s->l2_size * sizeof(uint64_t)) < 0) 426 return 0; 427 } else { 428 if (bdrv_pread(bs->file, l2_offset, l2_table, 429 s->l2_size * sizeof(uint64_t)) != 430 s->l2_size * sizeof(uint64_t)) 431 return 0; 432 } 433 s->l2_cache_offsets[min_index] = l2_offset; 434 s->l2_cache_counts[min_index] = 1; 435 found: 436 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 437 cluster_offset = be64_to_cpu(l2_table[l2_index]); 438 if (!cluster_offset || 439 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 440 if (!allocate) 441 return 0; 442 /* allocate a new cluster */ 443 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 444 (n_end - n_start) < s->cluster_sectors) { 445 /* if the cluster is already compressed, we must 446 decompress it in the case it is not completely 447 overwritten */ 448 if (decompress_cluster(bs, cluster_offset) < 0) 449 return 0; 450 cluster_offset = bdrv_getlength(bs->file->bs); 451 cluster_offset = (cluster_offset + s->cluster_size - 1) & 452 ~(s->cluster_size - 1); 453 /* write the cluster content */ 454 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 455 s->cluster_size) != 456 s->cluster_size) 457 return -1; 458 } else { 459 cluster_offset = bdrv_getlength(bs->file->bs); 460 if (allocate == 1) { 461 /* round to cluster size */ 462 cluster_offset = (cluster_offset + s->cluster_size - 1) & 463 ~(s->cluster_size - 1); 464 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size); 465 /* if encrypted, we must initialize the cluster 466 content which won't be written */ 467 if (bs->encrypted && 468 (n_end - n_start) < s->cluster_sectors) { 469 uint64_t start_sect; 470 assert(s->cipher); 471 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 472 memset(s->cluster_data + 512, 0x00, 512); 473 for(i = 0; i < s->cluster_sectors; i++) { 474 if (i < n_start || i >= n_end) { 475 Error *err = NULL; 476 if (encrypt_sectors(s, start_sect + i, 477 s->cluster_data, 478 s->cluster_data + 512, 1, 479 true, &err) < 0) { 480 error_free(err); 481 errno = EIO; 482 return -1; 483 } 484 if (bdrv_pwrite(bs->file, 485 cluster_offset + i * 512, 486 s->cluster_data, 512) != 512) 487 return -1; 488 } 489 } 490 } 491 } else if (allocate == 2) { 492 cluster_offset |= QCOW_OFLAG_COMPRESSED | 493 (uint64_t)compressed_size << (63 - s->cluster_bits); 494 } 495 } 496 /* update L2 table */ 497 tmp = cpu_to_be64(cluster_offset); 498 l2_table[l2_index] = tmp; 499 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 500 &tmp, sizeof(tmp)) < 0) 501 return 0; 502 } 503 return cluster_offset; 504 } 505 506 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 507 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 508 { 509 BDRVQcowState *s = bs->opaque; 510 int index_in_cluster, n; 511 uint64_t cluster_offset; 512 513 qemu_co_mutex_lock(&s->lock); 514 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 515 qemu_co_mutex_unlock(&s->lock); 516 index_in_cluster = sector_num & (s->cluster_sectors - 1); 517 n = s->cluster_sectors - index_in_cluster; 518 if (n > nb_sectors) 519 n = nb_sectors; 520 *pnum = n; 521 if (!cluster_offset) { 522 return 0; 523 } 524 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 525 return BDRV_BLOCK_DATA; 526 } 527 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 528 *file = bs->file->bs; 529 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 530 } 531 532 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 533 const uint8_t *buf, int buf_size) 534 { 535 z_stream strm1, *strm = &strm1; 536 int ret, out_len; 537 538 memset(strm, 0, sizeof(*strm)); 539 540 strm->next_in = (uint8_t *)buf; 541 strm->avail_in = buf_size; 542 strm->next_out = out_buf; 543 strm->avail_out = out_buf_size; 544 545 ret = inflateInit2(strm, -12); 546 if (ret != Z_OK) 547 return -1; 548 ret = inflate(strm, Z_FINISH); 549 out_len = strm->next_out - out_buf; 550 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 551 out_len != out_buf_size) { 552 inflateEnd(strm); 553 return -1; 554 } 555 inflateEnd(strm); 556 return 0; 557 } 558 559 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 560 { 561 BDRVQcowState *s = bs->opaque; 562 int ret, csize; 563 uint64_t coffset; 564 565 coffset = cluster_offset & s->cluster_offset_mask; 566 if (s->cluster_cache_offset != coffset) { 567 csize = cluster_offset >> (63 - s->cluster_bits); 568 csize &= (s->cluster_size - 1); 569 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 570 if (ret != csize) 571 return -1; 572 if (decompress_buffer(s->cluster_cache, s->cluster_size, 573 s->cluster_data, csize) < 0) { 574 return -1; 575 } 576 s->cluster_cache_offset = coffset; 577 } 578 return 0; 579 } 580 581 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 582 int nb_sectors, QEMUIOVector *qiov) 583 { 584 BDRVQcowState *s = bs->opaque; 585 int index_in_cluster; 586 int ret = 0, n; 587 uint64_t cluster_offset; 588 struct iovec hd_iov; 589 QEMUIOVector hd_qiov; 590 uint8_t *buf; 591 void *orig_buf; 592 Error *err = NULL; 593 594 if (qiov->niov > 1) { 595 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 596 if (buf == NULL) { 597 return -ENOMEM; 598 } 599 } else { 600 orig_buf = NULL; 601 buf = (uint8_t *)qiov->iov->iov_base; 602 } 603 604 qemu_co_mutex_lock(&s->lock); 605 606 while (nb_sectors != 0) { 607 /* prepare next request */ 608 cluster_offset = get_cluster_offset(bs, sector_num << 9, 609 0, 0, 0, 0); 610 index_in_cluster = sector_num & (s->cluster_sectors - 1); 611 n = s->cluster_sectors - index_in_cluster; 612 if (n > nb_sectors) { 613 n = nb_sectors; 614 } 615 616 if (!cluster_offset) { 617 if (bs->backing) { 618 /* read from the base image */ 619 hd_iov.iov_base = (void *)buf; 620 hd_iov.iov_len = n * 512; 621 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 622 qemu_co_mutex_unlock(&s->lock); 623 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 624 qemu_co_mutex_lock(&s->lock); 625 if (ret < 0) { 626 goto fail; 627 } 628 } else { 629 /* Note: in this case, no need to wait */ 630 memset(buf, 0, 512 * n); 631 } 632 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 633 /* add AIO support for compressed blocks ? */ 634 if (decompress_cluster(bs, cluster_offset) < 0) { 635 goto fail; 636 } 637 memcpy(buf, 638 s->cluster_cache + index_in_cluster * 512, 512 * n); 639 } else { 640 if ((cluster_offset & 511) != 0) { 641 goto fail; 642 } 643 hd_iov.iov_base = (void *)buf; 644 hd_iov.iov_len = n * 512; 645 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 646 qemu_co_mutex_unlock(&s->lock); 647 ret = bdrv_co_readv(bs->file, 648 (cluster_offset >> 9) + index_in_cluster, 649 n, &hd_qiov); 650 qemu_co_mutex_lock(&s->lock); 651 if (ret < 0) { 652 break; 653 } 654 if (bs->encrypted) { 655 assert(s->cipher); 656 if (encrypt_sectors(s, sector_num, buf, buf, 657 n, false, &err) < 0) { 658 goto fail; 659 } 660 } 661 } 662 ret = 0; 663 664 nb_sectors -= n; 665 sector_num += n; 666 buf += n * 512; 667 } 668 669 done: 670 qemu_co_mutex_unlock(&s->lock); 671 672 if (qiov->niov > 1) { 673 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 674 qemu_vfree(orig_buf); 675 } 676 677 return ret; 678 679 fail: 680 error_free(err); 681 ret = -EIO; 682 goto done; 683 } 684 685 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 686 int nb_sectors, QEMUIOVector *qiov) 687 { 688 BDRVQcowState *s = bs->opaque; 689 int index_in_cluster; 690 uint64_t cluster_offset; 691 const uint8_t *src_buf; 692 int ret = 0, n; 693 uint8_t *cluster_data = NULL; 694 struct iovec hd_iov; 695 QEMUIOVector hd_qiov; 696 uint8_t *buf; 697 void *orig_buf; 698 699 s->cluster_cache_offset = -1; /* disable compressed cache */ 700 701 if (qiov->niov > 1) { 702 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 703 if (buf == NULL) { 704 return -ENOMEM; 705 } 706 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 707 } else { 708 orig_buf = NULL; 709 buf = (uint8_t *)qiov->iov->iov_base; 710 } 711 712 qemu_co_mutex_lock(&s->lock); 713 714 while (nb_sectors != 0) { 715 716 index_in_cluster = sector_num & (s->cluster_sectors - 1); 717 n = s->cluster_sectors - index_in_cluster; 718 if (n > nb_sectors) { 719 n = nb_sectors; 720 } 721 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 722 index_in_cluster, 723 index_in_cluster + n); 724 if (!cluster_offset || (cluster_offset & 511) != 0) { 725 ret = -EIO; 726 break; 727 } 728 if (bs->encrypted) { 729 Error *err = NULL; 730 assert(s->cipher); 731 if (!cluster_data) { 732 cluster_data = g_malloc0(s->cluster_size); 733 } 734 if (encrypt_sectors(s, sector_num, cluster_data, buf, 735 n, true, &err) < 0) { 736 error_free(err); 737 ret = -EIO; 738 break; 739 } 740 src_buf = cluster_data; 741 } else { 742 src_buf = buf; 743 } 744 745 hd_iov.iov_base = (void *)src_buf; 746 hd_iov.iov_len = n * 512; 747 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 748 qemu_co_mutex_unlock(&s->lock); 749 ret = bdrv_co_writev(bs->file, 750 (cluster_offset >> 9) + index_in_cluster, 751 n, &hd_qiov); 752 qemu_co_mutex_lock(&s->lock); 753 if (ret < 0) { 754 break; 755 } 756 ret = 0; 757 758 nb_sectors -= n; 759 sector_num += n; 760 buf += n * 512; 761 } 762 qemu_co_mutex_unlock(&s->lock); 763 764 if (qiov->niov > 1) { 765 qemu_vfree(orig_buf); 766 } 767 g_free(cluster_data); 768 769 return ret; 770 } 771 772 static void qcow_close(BlockDriverState *bs) 773 { 774 BDRVQcowState *s = bs->opaque; 775 776 qcrypto_cipher_free(s->cipher); 777 s->cipher = NULL; 778 g_free(s->l1_table); 779 qemu_vfree(s->l2_cache); 780 g_free(s->cluster_cache); 781 g_free(s->cluster_data); 782 783 migrate_del_blocker(s->migration_blocker); 784 error_free(s->migration_blocker); 785 } 786 787 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 788 { 789 int header_size, backing_filename_len, l1_size, shift, i; 790 QCowHeader header; 791 uint8_t *tmp; 792 int64_t total_size = 0; 793 char *backing_file = NULL; 794 int flags = 0; 795 Error *local_err = NULL; 796 int ret; 797 BlockBackend *qcow_blk; 798 799 /* Read out options */ 800 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 801 BDRV_SECTOR_SIZE); 802 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 803 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 804 flags |= BLOCK_FLAG_ENCRYPT; 805 } 806 807 ret = bdrv_create_file(filename, opts, &local_err); 808 if (ret < 0) { 809 error_propagate(errp, local_err); 810 goto cleanup; 811 } 812 813 qcow_blk = blk_new_open(filename, NULL, NULL, 814 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); 815 if (qcow_blk == NULL) { 816 error_propagate(errp, local_err); 817 ret = -EIO; 818 goto cleanup; 819 } 820 821 blk_set_allow_write_beyond_eof(qcow_blk, true); 822 823 ret = blk_truncate(qcow_blk, 0); 824 if (ret < 0) { 825 goto exit; 826 } 827 828 memset(&header, 0, sizeof(header)); 829 header.magic = cpu_to_be32(QCOW_MAGIC); 830 header.version = cpu_to_be32(QCOW_VERSION); 831 header.size = cpu_to_be64(total_size); 832 header_size = sizeof(header); 833 backing_filename_len = 0; 834 if (backing_file) { 835 if (strcmp(backing_file, "fat:")) { 836 header.backing_file_offset = cpu_to_be64(header_size); 837 backing_filename_len = strlen(backing_file); 838 header.backing_file_size = cpu_to_be32(backing_filename_len); 839 header_size += backing_filename_len; 840 } else { 841 /* special backing file for vvfat */ 842 backing_file = NULL; 843 } 844 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 845 unmodified sectors */ 846 header.l2_bits = 12; /* 32 KB L2 tables */ 847 } else { 848 header.cluster_bits = 12; /* 4 KB clusters */ 849 header.l2_bits = 9; /* 4 KB L2 tables */ 850 } 851 header_size = (header_size + 7) & ~7; 852 shift = header.cluster_bits + header.l2_bits; 853 l1_size = (total_size + (1LL << shift) - 1) >> shift; 854 855 header.l1_table_offset = cpu_to_be64(header_size); 856 if (flags & BLOCK_FLAG_ENCRYPT) { 857 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 858 } else { 859 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 860 } 861 862 /* write all the data */ 863 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 864 if (ret != sizeof(header)) { 865 goto exit; 866 } 867 868 if (backing_file) { 869 ret = blk_pwrite(qcow_blk, sizeof(header), 870 backing_file, backing_filename_len, 0); 871 if (ret != backing_filename_len) { 872 goto exit; 873 } 874 } 875 876 tmp = g_malloc0(BDRV_SECTOR_SIZE); 877 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 878 i++) { 879 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 880 tmp, BDRV_SECTOR_SIZE, 0); 881 if (ret != BDRV_SECTOR_SIZE) { 882 g_free(tmp); 883 goto exit; 884 } 885 } 886 887 g_free(tmp); 888 ret = 0; 889 exit: 890 blk_unref(qcow_blk); 891 cleanup: 892 g_free(backing_file); 893 return ret; 894 } 895 896 static int qcow_make_empty(BlockDriverState *bs) 897 { 898 BDRVQcowState *s = bs->opaque; 899 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 900 int ret; 901 902 memset(s->l1_table, 0, l1_length); 903 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 904 l1_length) < 0) 905 return -1; 906 ret = bdrv_truncate(bs->file->bs, s->l1_table_offset + l1_length); 907 if (ret < 0) 908 return ret; 909 910 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 911 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 912 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 913 914 return 0; 915 } 916 917 /* XXX: put compressed sectors first, then all the cluster aligned 918 tables to avoid losing bytes in alignment */ 919 static coroutine_fn int 920 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 921 uint64_t bytes, QEMUIOVector *qiov) 922 { 923 BDRVQcowState *s = bs->opaque; 924 QEMUIOVector hd_qiov; 925 struct iovec iov; 926 z_stream strm; 927 int ret, out_len; 928 uint8_t *buf, *out_buf; 929 uint64_t cluster_offset; 930 931 buf = qemu_blockalign(bs, s->cluster_size); 932 if (bytes != s->cluster_size) { 933 if (bytes > s->cluster_size || 934 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 935 { 936 qemu_vfree(buf); 937 return -EINVAL; 938 } 939 /* Zero-pad last write if image size is not cluster aligned */ 940 memset(buf + bytes, 0, s->cluster_size - bytes); 941 } 942 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 943 944 out_buf = g_malloc(s->cluster_size); 945 946 /* best compression, small window, no zlib header */ 947 memset(&strm, 0, sizeof(strm)); 948 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 949 Z_DEFLATED, -12, 950 9, Z_DEFAULT_STRATEGY); 951 if (ret != 0) { 952 ret = -EINVAL; 953 goto fail; 954 } 955 956 strm.avail_in = s->cluster_size; 957 strm.next_in = (uint8_t *)buf; 958 strm.avail_out = s->cluster_size; 959 strm.next_out = out_buf; 960 961 ret = deflate(&strm, Z_FINISH); 962 if (ret != Z_STREAM_END && ret != Z_OK) { 963 deflateEnd(&strm); 964 ret = -EINVAL; 965 goto fail; 966 } 967 out_len = strm.next_out - out_buf; 968 969 deflateEnd(&strm); 970 971 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 972 /* could not compress: write normal cluster */ 973 ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS, 974 bytes >> BDRV_SECTOR_BITS, qiov); 975 if (ret < 0) { 976 goto fail; 977 } 978 goto success; 979 } 980 qemu_co_mutex_lock(&s->lock); 981 cluster_offset = get_cluster_offset(bs, offset, 2, out_len, 0, 0); 982 qemu_co_mutex_unlock(&s->lock); 983 if (cluster_offset == 0) { 984 ret = -EIO; 985 goto fail; 986 } 987 cluster_offset &= s->cluster_offset_mask; 988 989 iov = (struct iovec) { 990 .iov_base = out_buf, 991 .iov_len = out_len, 992 }; 993 qemu_iovec_init_external(&hd_qiov, &iov, 1); 994 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 995 if (ret < 0) { 996 goto fail; 997 } 998 success: 999 ret = 0; 1000 fail: 1001 qemu_vfree(buf); 1002 g_free(out_buf); 1003 return ret; 1004 } 1005 1006 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1007 { 1008 BDRVQcowState *s = bs->opaque; 1009 bdi->cluster_size = s->cluster_size; 1010 return 0; 1011 } 1012 1013 static QemuOptsList qcow_create_opts = { 1014 .name = "qcow-create-opts", 1015 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1016 .desc = { 1017 { 1018 .name = BLOCK_OPT_SIZE, 1019 .type = QEMU_OPT_SIZE, 1020 .help = "Virtual disk size" 1021 }, 1022 { 1023 .name = BLOCK_OPT_BACKING_FILE, 1024 .type = QEMU_OPT_STRING, 1025 .help = "File name of a base image" 1026 }, 1027 { 1028 .name = BLOCK_OPT_ENCRYPT, 1029 .type = QEMU_OPT_BOOL, 1030 .help = "Encrypt the image", 1031 .def_value_str = "off" 1032 }, 1033 { /* end of list */ } 1034 } 1035 }; 1036 1037 static BlockDriver bdrv_qcow = { 1038 .format_name = "qcow", 1039 .instance_size = sizeof(BDRVQcowState), 1040 .bdrv_probe = qcow_probe, 1041 .bdrv_open = qcow_open, 1042 .bdrv_close = qcow_close, 1043 .bdrv_reopen_prepare = qcow_reopen_prepare, 1044 .bdrv_create = qcow_create, 1045 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1046 .supports_backing = true, 1047 1048 .bdrv_co_readv = qcow_co_readv, 1049 .bdrv_co_writev = qcow_co_writev, 1050 .bdrv_co_get_block_status = qcow_co_get_block_status, 1051 1052 .bdrv_set_key = qcow_set_key, 1053 .bdrv_make_empty = qcow_make_empty, 1054 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1055 .bdrv_get_info = qcow_get_info, 1056 1057 .create_opts = &qcow_create_opts, 1058 }; 1059 1060 static void bdrv_qcow_init(void) 1061 { 1062 bdrv_register(&bdrv_qcow); 1063 } 1064 1065 block_init(bdrv_qcow_init); 1066