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 Error *local_err = NULL; 108 109 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 110 false, errp); 111 if (!bs->file) { 112 return -EINVAL; 113 } 114 115 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 116 if (ret < 0) { 117 goto fail; 118 } 119 be32_to_cpus(&header.magic); 120 be32_to_cpus(&header.version); 121 be64_to_cpus(&header.backing_file_offset); 122 be32_to_cpus(&header.backing_file_size); 123 be32_to_cpus(&header.mtime); 124 be64_to_cpus(&header.size); 125 be32_to_cpus(&header.crypt_method); 126 be64_to_cpus(&header.l1_table_offset); 127 128 if (header.magic != QCOW_MAGIC) { 129 error_setg(errp, "Image not in qcow format"); 130 ret = -EINVAL; 131 goto fail; 132 } 133 if (header.version != QCOW_VERSION) { 134 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 135 ret = -ENOTSUP; 136 goto fail; 137 } 138 139 if (header.size <= 1) { 140 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 141 ret = -EINVAL; 142 goto fail; 143 } 144 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 145 error_setg(errp, "Cluster size must be between 512 and 64k"); 146 ret = -EINVAL; 147 goto fail; 148 } 149 150 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 151 * so bytes = num_entries << 3. */ 152 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 153 error_setg(errp, "L2 table size must be between 512 and 64k"); 154 ret = -EINVAL; 155 goto fail; 156 } 157 158 if (header.crypt_method > QCOW_CRYPT_AES) { 159 error_setg(errp, "invalid encryption method in qcow header"); 160 ret = -EINVAL; 161 goto fail; 162 } 163 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128, 164 QCRYPTO_CIPHER_MODE_CBC)) { 165 error_setg(errp, "AES cipher not available"); 166 ret = -EINVAL; 167 goto fail; 168 } 169 s->crypt_method_header = header.crypt_method; 170 if (s->crypt_method_header) { 171 if (bdrv_uses_whitelist() && 172 s->crypt_method_header == QCOW_CRYPT_AES) { 173 error_setg(errp, 174 "Use of AES-CBC encrypted qcow images is no longer " 175 "supported in system emulators"); 176 error_append_hint(errp, 177 "You can use 'qemu-img convert' to convert your " 178 "image to an alternative supported format, such " 179 "as unencrypted qcow, or raw with the LUKS " 180 "format instead.\n"); 181 ret = -ENOSYS; 182 goto fail; 183 } 184 185 bs->encrypted = true; 186 } 187 s->cluster_bits = header.cluster_bits; 188 s->cluster_size = 1 << s->cluster_bits; 189 s->cluster_sectors = 1 << (s->cluster_bits - 9); 190 s->l2_bits = header.l2_bits; 191 s->l2_size = 1 << s->l2_bits; 192 bs->total_sectors = header.size / 512; 193 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 194 195 /* read the level 1 table */ 196 shift = s->cluster_bits + s->l2_bits; 197 if (header.size > UINT64_MAX - (1LL << shift)) { 198 error_setg(errp, "Image too large"); 199 ret = -EINVAL; 200 goto fail; 201 } else { 202 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 203 if (l1_size > INT_MAX / sizeof(uint64_t)) { 204 error_setg(errp, "Image too large"); 205 ret = -EINVAL; 206 goto fail; 207 } 208 s->l1_size = l1_size; 209 } 210 211 s->l1_table_offset = header.l1_table_offset; 212 s->l1_table = g_try_new(uint64_t, s->l1_size); 213 if (s->l1_table == NULL) { 214 error_setg(errp, "Could not allocate memory for L1 table"); 215 ret = -ENOMEM; 216 goto fail; 217 } 218 219 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 220 s->l1_size * sizeof(uint64_t)); 221 if (ret < 0) { 222 goto fail; 223 } 224 225 for(i = 0;i < s->l1_size; i++) { 226 be64_to_cpus(&s->l1_table[i]); 227 } 228 229 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 230 s->l2_cache = 231 qemu_try_blockalign(bs->file->bs, 232 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 233 if (s->l2_cache == NULL) { 234 error_setg(errp, "Could not allocate L2 table cache"); 235 ret = -ENOMEM; 236 goto fail; 237 } 238 s->cluster_cache = g_malloc(s->cluster_size); 239 s->cluster_data = g_malloc(s->cluster_size); 240 s->cluster_cache_offset = -1; 241 242 /* read the backing file name */ 243 if (header.backing_file_offset != 0) { 244 len = header.backing_file_size; 245 if (len > 1023 || len >= sizeof(bs->backing_file)) { 246 error_setg(errp, "Backing file name too long"); 247 ret = -EINVAL; 248 goto fail; 249 } 250 ret = bdrv_pread(bs->file, header.backing_file_offset, 251 bs->backing_file, len); 252 if (ret < 0) { 253 goto fail; 254 } 255 bs->backing_file[len] = '\0'; 256 } 257 258 /* Disable migration when qcow images are used */ 259 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 260 "does not support live migration", 261 bdrv_get_device_or_node_name(bs)); 262 ret = migrate_add_blocker(s->migration_blocker, &local_err); 263 if (local_err) { 264 error_propagate(errp, local_err); 265 error_free(s->migration_blocker); 266 goto fail; 267 } 268 269 qemu_co_mutex_init(&s->lock); 270 return 0; 271 272 fail: 273 g_free(s->l1_table); 274 qemu_vfree(s->l2_cache); 275 g_free(s->cluster_cache); 276 g_free(s->cluster_data); 277 return ret; 278 } 279 280 281 /* We have nothing to do for QCOW reopen, stubs just return 282 * success */ 283 static int qcow_reopen_prepare(BDRVReopenState *state, 284 BlockReopenQueue *queue, Error **errp) 285 { 286 return 0; 287 } 288 289 static int qcow_set_key(BlockDriverState *bs, const char *key) 290 { 291 BDRVQcowState *s = bs->opaque; 292 uint8_t keybuf[16]; 293 int len, i; 294 Error *err; 295 296 memset(keybuf, 0, 16); 297 len = strlen(key); 298 if (len > 16) 299 len = 16; 300 /* XXX: we could compress the chars to 7 bits to increase 301 entropy */ 302 for(i = 0;i < len;i++) { 303 keybuf[i] = key[i]; 304 } 305 assert(bs->encrypted); 306 307 qcrypto_cipher_free(s->cipher); 308 s->cipher = qcrypto_cipher_new( 309 QCRYPTO_CIPHER_ALG_AES_128, 310 QCRYPTO_CIPHER_MODE_CBC, 311 keybuf, G_N_ELEMENTS(keybuf), 312 &err); 313 314 if (!s->cipher) { 315 /* XXX would be nice if errors in this method could 316 * be properly propagate to the caller. Would need 317 * the bdrv_set_key() API signature to be fixed. */ 318 error_free(err); 319 return -1; 320 } 321 return 0; 322 } 323 324 /* The crypt function is compatible with the linux cryptoloop 325 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 326 supported */ 327 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 328 uint8_t *out_buf, const uint8_t *in_buf, 329 int nb_sectors, bool enc, Error **errp) 330 { 331 union { 332 uint64_t ll[2]; 333 uint8_t b[16]; 334 } ivec; 335 int i; 336 int ret; 337 338 for(i = 0; i < nb_sectors; i++) { 339 ivec.ll[0] = cpu_to_le64(sector_num); 340 ivec.ll[1] = 0; 341 if (qcrypto_cipher_setiv(s->cipher, 342 ivec.b, G_N_ELEMENTS(ivec.b), 343 errp) < 0) { 344 return -1; 345 } 346 if (enc) { 347 ret = qcrypto_cipher_encrypt(s->cipher, 348 in_buf, 349 out_buf, 350 512, 351 errp); 352 } else { 353 ret = qcrypto_cipher_decrypt(s->cipher, 354 in_buf, 355 out_buf, 356 512, 357 errp); 358 } 359 if (ret < 0) { 360 return -1; 361 } 362 sector_num++; 363 in_buf += 512; 364 out_buf += 512; 365 } 366 return 0; 367 } 368 369 /* 'allocate' is: 370 * 371 * 0 to not allocate. 372 * 373 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 374 * 'n_end') 375 * 376 * 2 to allocate a compressed cluster of size 377 * 'compressed_size'. 'compressed_size' must be > 0 and < 378 * cluster_size 379 * 380 * return 0 if not allocated. 381 */ 382 static uint64_t get_cluster_offset(BlockDriverState *bs, 383 uint64_t offset, int allocate, 384 int compressed_size, 385 int n_start, int n_end) 386 { 387 BDRVQcowState *s = bs->opaque; 388 int min_index, i, j, l1_index, l2_index; 389 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 390 uint32_t min_count; 391 int new_l2_table; 392 393 l1_index = offset >> (s->l2_bits + s->cluster_bits); 394 l2_offset = s->l1_table[l1_index]; 395 new_l2_table = 0; 396 if (!l2_offset) { 397 if (!allocate) 398 return 0; 399 /* allocate a new l2 entry */ 400 l2_offset = bdrv_getlength(bs->file->bs); 401 /* round to cluster size */ 402 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 403 /* update the L1 entry */ 404 s->l1_table[l1_index] = l2_offset; 405 tmp = cpu_to_be64(l2_offset); 406 if (bdrv_pwrite_sync(bs->file, 407 s->l1_table_offset + l1_index * sizeof(tmp), 408 &tmp, sizeof(tmp)) < 0) 409 return 0; 410 new_l2_table = 1; 411 } 412 for(i = 0; i < L2_CACHE_SIZE; i++) { 413 if (l2_offset == s->l2_cache_offsets[i]) { 414 /* increment the hit count */ 415 if (++s->l2_cache_counts[i] == 0xffffffff) { 416 for(j = 0; j < L2_CACHE_SIZE; j++) { 417 s->l2_cache_counts[j] >>= 1; 418 } 419 } 420 l2_table = s->l2_cache + (i << s->l2_bits); 421 goto found; 422 } 423 } 424 /* not found: load a new entry in the least used one */ 425 min_index = 0; 426 min_count = 0xffffffff; 427 for(i = 0; i < L2_CACHE_SIZE; i++) { 428 if (s->l2_cache_counts[i] < min_count) { 429 min_count = s->l2_cache_counts[i]; 430 min_index = i; 431 } 432 } 433 l2_table = s->l2_cache + (min_index << s->l2_bits); 434 if (new_l2_table) { 435 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 436 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 437 s->l2_size * sizeof(uint64_t)) < 0) 438 return 0; 439 } else { 440 if (bdrv_pread(bs->file, l2_offset, l2_table, 441 s->l2_size * sizeof(uint64_t)) != 442 s->l2_size * sizeof(uint64_t)) 443 return 0; 444 } 445 s->l2_cache_offsets[min_index] = l2_offset; 446 s->l2_cache_counts[min_index] = 1; 447 found: 448 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 449 cluster_offset = be64_to_cpu(l2_table[l2_index]); 450 if (!cluster_offset || 451 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 452 if (!allocate) 453 return 0; 454 /* allocate a new cluster */ 455 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 456 (n_end - n_start) < s->cluster_sectors) { 457 /* if the cluster is already compressed, we must 458 decompress it in the case it is not completely 459 overwritten */ 460 if (decompress_cluster(bs, cluster_offset) < 0) 461 return 0; 462 cluster_offset = bdrv_getlength(bs->file->bs); 463 cluster_offset = (cluster_offset + s->cluster_size - 1) & 464 ~(s->cluster_size - 1); 465 /* write the cluster content */ 466 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 467 s->cluster_size) != 468 s->cluster_size) 469 return -1; 470 } else { 471 cluster_offset = bdrv_getlength(bs->file->bs); 472 if (allocate == 1) { 473 /* round to cluster size */ 474 cluster_offset = (cluster_offset + s->cluster_size - 1) & 475 ~(s->cluster_size - 1); 476 bdrv_truncate(bs->file, cluster_offset + s->cluster_size, NULL); 477 /* if encrypted, we must initialize the cluster 478 content which won't be written */ 479 if (bs->encrypted && 480 (n_end - n_start) < s->cluster_sectors) { 481 uint64_t start_sect; 482 assert(s->cipher); 483 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 484 memset(s->cluster_data + 512, 0x00, 512); 485 for(i = 0; i < s->cluster_sectors; i++) { 486 if (i < n_start || i >= n_end) { 487 Error *err = NULL; 488 if (encrypt_sectors(s, start_sect + i, 489 s->cluster_data, 490 s->cluster_data + 512, 1, 491 true, &err) < 0) { 492 error_free(err); 493 errno = EIO; 494 return -1; 495 } 496 if (bdrv_pwrite(bs->file, 497 cluster_offset + i * 512, 498 s->cluster_data, 512) != 512) 499 return -1; 500 } 501 } 502 } 503 } else if (allocate == 2) { 504 cluster_offset |= QCOW_OFLAG_COMPRESSED | 505 (uint64_t)compressed_size << (63 - s->cluster_bits); 506 } 507 } 508 /* update L2 table */ 509 tmp = cpu_to_be64(cluster_offset); 510 l2_table[l2_index] = tmp; 511 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 512 &tmp, sizeof(tmp)) < 0) 513 return 0; 514 } 515 return cluster_offset; 516 } 517 518 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 519 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 520 { 521 BDRVQcowState *s = bs->opaque; 522 int index_in_cluster, n; 523 uint64_t cluster_offset; 524 525 qemu_co_mutex_lock(&s->lock); 526 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 527 qemu_co_mutex_unlock(&s->lock); 528 index_in_cluster = sector_num & (s->cluster_sectors - 1); 529 n = s->cluster_sectors - index_in_cluster; 530 if (n > nb_sectors) 531 n = nb_sectors; 532 *pnum = n; 533 if (!cluster_offset) { 534 return 0; 535 } 536 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 537 return BDRV_BLOCK_DATA; 538 } 539 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 540 *file = bs->file->bs; 541 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 542 } 543 544 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 545 const uint8_t *buf, int buf_size) 546 { 547 z_stream strm1, *strm = &strm1; 548 int ret, out_len; 549 550 memset(strm, 0, sizeof(*strm)); 551 552 strm->next_in = (uint8_t *)buf; 553 strm->avail_in = buf_size; 554 strm->next_out = out_buf; 555 strm->avail_out = out_buf_size; 556 557 ret = inflateInit2(strm, -12); 558 if (ret != Z_OK) 559 return -1; 560 ret = inflate(strm, Z_FINISH); 561 out_len = strm->next_out - out_buf; 562 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 563 out_len != out_buf_size) { 564 inflateEnd(strm); 565 return -1; 566 } 567 inflateEnd(strm); 568 return 0; 569 } 570 571 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 572 { 573 BDRVQcowState *s = bs->opaque; 574 int ret, csize; 575 uint64_t coffset; 576 577 coffset = cluster_offset & s->cluster_offset_mask; 578 if (s->cluster_cache_offset != coffset) { 579 csize = cluster_offset >> (63 - s->cluster_bits); 580 csize &= (s->cluster_size - 1); 581 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 582 if (ret != csize) 583 return -1; 584 if (decompress_buffer(s->cluster_cache, s->cluster_size, 585 s->cluster_data, csize) < 0) { 586 return -1; 587 } 588 s->cluster_cache_offset = coffset; 589 } 590 return 0; 591 } 592 593 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 594 int nb_sectors, QEMUIOVector *qiov) 595 { 596 BDRVQcowState *s = bs->opaque; 597 int index_in_cluster; 598 int ret = 0, n; 599 uint64_t cluster_offset; 600 struct iovec hd_iov; 601 QEMUIOVector hd_qiov; 602 uint8_t *buf; 603 void *orig_buf; 604 Error *err = NULL; 605 606 if (qiov->niov > 1) { 607 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 608 if (buf == NULL) { 609 return -ENOMEM; 610 } 611 } else { 612 orig_buf = NULL; 613 buf = (uint8_t *)qiov->iov->iov_base; 614 } 615 616 qemu_co_mutex_lock(&s->lock); 617 618 while (nb_sectors != 0) { 619 /* prepare next request */ 620 cluster_offset = get_cluster_offset(bs, sector_num << 9, 621 0, 0, 0, 0); 622 index_in_cluster = sector_num & (s->cluster_sectors - 1); 623 n = s->cluster_sectors - index_in_cluster; 624 if (n > nb_sectors) { 625 n = nb_sectors; 626 } 627 628 if (!cluster_offset) { 629 if (bs->backing) { 630 /* read from the base image */ 631 hd_iov.iov_base = (void *)buf; 632 hd_iov.iov_len = n * 512; 633 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 634 qemu_co_mutex_unlock(&s->lock); 635 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 636 qemu_co_mutex_lock(&s->lock); 637 if (ret < 0) { 638 goto fail; 639 } 640 } else { 641 /* Note: in this case, no need to wait */ 642 memset(buf, 0, 512 * n); 643 } 644 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 645 /* add AIO support for compressed blocks ? */ 646 if (decompress_cluster(bs, cluster_offset) < 0) { 647 goto fail; 648 } 649 memcpy(buf, 650 s->cluster_cache + index_in_cluster * 512, 512 * n); 651 } else { 652 if ((cluster_offset & 511) != 0) { 653 goto fail; 654 } 655 hd_iov.iov_base = (void *)buf; 656 hd_iov.iov_len = n * 512; 657 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 658 qemu_co_mutex_unlock(&s->lock); 659 ret = bdrv_co_readv(bs->file, 660 (cluster_offset >> 9) + index_in_cluster, 661 n, &hd_qiov); 662 qemu_co_mutex_lock(&s->lock); 663 if (ret < 0) { 664 break; 665 } 666 if (bs->encrypted) { 667 assert(s->cipher); 668 if (encrypt_sectors(s, sector_num, buf, buf, 669 n, false, &err) < 0) { 670 goto fail; 671 } 672 } 673 } 674 ret = 0; 675 676 nb_sectors -= n; 677 sector_num += n; 678 buf += n * 512; 679 } 680 681 done: 682 qemu_co_mutex_unlock(&s->lock); 683 684 if (qiov->niov > 1) { 685 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 686 qemu_vfree(orig_buf); 687 } 688 689 return ret; 690 691 fail: 692 error_free(err); 693 ret = -EIO; 694 goto done; 695 } 696 697 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 698 int nb_sectors, QEMUIOVector *qiov) 699 { 700 BDRVQcowState *s = bs->opaque; 701 int index_in_cluster; 702 uint64_t cluster_offset; 703 const uint8_t *src_buf; 704 int ret = 0, n; 705 uint8_t *cluster_data = NULL; 706 struct iovec hd_iov; 707 QEMUIOVector hd_qiov; 708 uint8_t *buf; 709 void *orig_buf; 710 711 s->cluster_cache_offset = -1; /* disable compressed cache */ 712 713 if (qiov->niov > 1) { 714 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 715 if (buf == NULL) { 716 return -ENOMEM; 717 } 718 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 719 } else { 720 orig_buf = NULL; 721 buf = (uint8_t *)qiov->iov->iov_base; 722 } 723 724 qemu_co_mutex_lock(&s->lock); 725 726 while (nb_sectors != 0) { 727 728 index_in_cluster = sector_num & (s->cluster_sectors - 1); 729 n = s->cluster_sectors - index_in_cluster; 730 if (n > nb_sectors) { 731 n = nb_sectors; 732 } 733 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 734 index_in_cluster, 735 index_in_cluster + n); 736 if (!cluster_offset || (cluster_offset & 511) != 0) { 737 ret = -EIO; 738 break; 739 } 740 if (bs->encrypted) { 741 Error *err = NULL; 742 assert(s->cipher); 743 if (!cluster_data) { 744 cluster_data = g_malloc0(s->cluster_size); 745 } 746 if (encrypt_sectors(s, sector_num, cluster_data, buf, 747 n, true, &err) < 0) { 748 error_free(err); 749 ret = -EIO; 750 break; 751 } 752 src_buf = cluster_data; 753 } else { 754 src_buf = buf; 755 } 756 757 hd_iov.iov_base = (void *)src_buf; 758 hd_iov.iov_len = n * 512; 759 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 760 qemu_co_mutex_unlock(&s->lock); 761 ret = bdrv_co_writev(bs->file, 762 (cluster_offset >> 9) + index_in_cluster, 763 n, &hd_qiov); 764 qemu_co_mutex_lock(&s->lock); 765 if (ret < 0) { 766 break; 767 } 768 ret = 0; 769 770 nb_sectors -= n; 771 sector_num += n; 772 buf += n * 512; 773 } 774 qemu_co_mutex_unlock(&s->lock); 775 776 if (qiov->niov > 1) { 777 qemu_vfree(orig_buf); 778 } 779 g_free(cluster_data); 780 781 return ret; 782 } 783 784 static void qcow_close(BlockDriverState *bs) 785 { 786 BDRVQcowState *s = bs->opaque; 787 788 qcrypto_cipher_free(s->cipher); 789 s->cipher = NULL; 790 g_free(s->l1_table); 791 qemu_vfree(s->l2_cache); 792 g_free(s->cluster_cache); 793 g_free(s->cluster_data); 794 795 migrate_del_blocker(s->migration_blocker); 796 error_free(s->migration_blocker); 797 } 798 799 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 800 { 801 int header_size, backing_filename_len, l1_size, shift, i; 802 QCowHeader header; 803 uint8_t *tmp; 804 int64_t total_size = 0; 805 char *backing_file = NULL; 806 int flags = 0; 807 Error *local_err = NULL; 808 int ret; 809 BlockBackend *qcow_blk; 810 811 /* Read out options */ 812 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 813 BDRV_SECTOR_SIZE); 814 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 815 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 816 flags |= BLOCK_FLAG_ENCRYPT; 817 } 818 819 ret = bdrv_create_file(filename, opts, &local_err); 820 if (ret < 0) { 821 error_propagate(errp, local_err); 822 goto cleanup; 823 } 824 825 qcow_blk = blk_new_open(filename, NULL, NULL, 826 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 827 &local_err); 828 if (qcow_blk == NULL) { 829 error_propagate(errp, local_err); 830 ret = -EIO; 831 goto cleanup; 832 } 833 834 blk_set_allow_write_beyond_eof(qcow_blk, true); 835 836 ret = blk_truncate(qcow_blk, 0, errp); 837 if (ret < 0) { 838 goto exit; 839 } 840 841 memset(&header, 0, sizeof(header)); 842 header.magic = cpu_to_be32(QCOW_MAGIC); 843 header.version = cpu_to_be32(QCOW_VERSION); 844 header.size = cpu_to_be64(total_size); 845 header_size = sizeof(header); 846 backing_filename_len = 0; 847 if (backing_file) { 848 if (strcmp(backing_file, "fat:")) { 849 header.backing_file_offset = cpu_to_be64(header_size); 850 backing_filename_len = strlen(backing_file); 851 header.backing_file_size = cpu_to_be32(backing_filename_len); 852 header_size += backing_filename_len; 853 } else { 854 /* special backing file for vvfat */ 855 backing_file = NULL; 856 } 857 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 858 unmodified sectors */ 859 header.l2_bits = 12; /* 32 KB L2 tables */ 860 } else { 861 header.cluster_bits = 12; /* 4 KB clusters */ 862 header.l2_bits = 9; /* 4 KB L2 tables */ 863 } 864 header_size = (header_size + 7) & ~7; 865 shift = header.cluster_bits + header.l2_bits; 866 l1_size = (total_size + (1LL << shift) - 1) >> shift; 867 868 header.l1_table_offset = cpu_to_be64(header_size); 869 if (flags & BLOCK_FLAG_ENCRYPT) { 870 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 871 } else { 872 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 873 } 874 875 /* write all the data */ 876 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 877 if (ret != sizeof(header)) { 878 goto exit; 879 } 880 881 if (backing_file) { 882 ret = blk_pwrite(qcow_blk, sizeof(header), 883 backing_file, backing_filename_len, 0); 884 if (ret != backing_filename_len) { 885 goto exit; 886 } 887 } 888 889 tmp = g_malloc0(BDRV_SECTOR_SIZE); 890 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 891 i++) { 892 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 893 tmp, BDRV_SECTOR_SIZE, 0); 894 if (ret != BDRV_SECTOR_SIZE) { 895 g_free(tmp); 896 goto exit; 897 } 898 } 899 900 g_free(tmp); 901 ret = 0; 902 exit: 903 blk_unref(qcow_blk); 904 cleanup: 905 g_free(backing_file); 906 return ret; 907 } 908 909 static int qcow_make_empty(BlockDriverState *bs) 910 { 911 BDRVQcowState *s = bs->opaque; 912 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 913 int ret; 914 915 memset(s->l1_table, 0, l1_length); 916 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 917 l1_length) < 0) 918 return -1; 919 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, NULL); 920 if (ret < 0) 921 return ret; 922 923 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 924 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 925 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 926 927 return 0; 928 } 929 930 /* XXX: put compressed sectors first, then all the cluster aligned 931 tables to avoid losing bytes in alignment */ 932 static coroutine_fn int 933 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 934 uint64_t bytes, QEMUIOVector *qiov) 935 { 936 BDRVQcowState *s = bs->opaque; 937 QEMUIOVector hd_qiov; 938 struct iovec iov; 939 z_stream strm; 940 int ret, out_len; 941 uint8_t *buf, *out_buf; 942 uint64_t cluster_offset; 943 944 buf = qemu_blockalign(bs, s->cluster_size); 945 if (bytes != s->cluster_size) { 946 if (bytes > s->cluster_size || 947 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 948 { 949 qemu_vfree(buf); 950 return -EINVAL; 951 } 952 /* Zero-pad last write if image size is not cluster aligned */ 953 memset(buf + bytes, 0, s->cluster_size - bytes); 954 } 955 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 956 957 out_buf = g_malloc(s->cluster_size); 958 959 /* best compression, small window, no zlib header */ 960 memset(&strm, 0, sizeof(strm)); 961 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 962 Z_DEFLATED, -12, 963 9, Z_DEFAULT_STRATEGY); 964 if (ret != 0) { 965 ret = -EINVAL; 966 goto fail; 967 } 968 969 strm.avail_in = s->cluster_size; 970 strm.next_in = (uint8_t *)buf; 971 strm.avail_out = s->cluster_size; 972 strm.next_out = out_buf; 973 974 ret = deflate(&strm, Z_FINISH); 975 if (ret != Z_STREAM_END && ret != Z_OK) { 976 deflateEnd(&strm); 977 ret = -EINVAL; 978 goto fail; 979 } 980 out_len = strm.next_out - out_buf; 981 982 deflateEnd(&strm); 983 984 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 985 /* could not compress: write normal cluster */ 986 ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS, 987 bytes >> BDRV_SECTOR_BITS, qiov); 988 if (ret < 0) { 989 goto fail; 990 } 991 goto success; 992 } 993 qemu_co_mutex_lock(&s->lock); 994 cluster_offset = get_cluster_offset(bs, offset, 2, out_len, 0, 0); 995 qemu_co_mutex_unlock(&s->lock); 996 if (cluster_offset == 0) { 997 ret = -EIO; 998 goto fail; 999 } 1000 cluster_offset &= s->cluster_offset_mask; 1001 1002 iov = (struct iovec) { 1003 .iov_base = out_buf, 1004 .iov_len = out_len, 1005 }; 1006 qemu_iovec_init_external(&hd_qiov, &iov, 1); 1007 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1008 if (ret < 0) { 1009 goto fail; 1010 } 1011 success: 1012 ret = 0; 1013 fail: 1014 qemu_vfree(buf); 1015 g_free(out_buf); 1016 return ret; 1017 } 1018 1019 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1020 { 1021 BDRVQcowState *s = bs->opaque; 1022 bdi->cluster_size = s->cluster_size; 1023 return 0; 1024 } 1025 1026 static QemuOptsList qcow_create_opts = { 1027 .name = "qcow-create-opts", 1028 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1029 .desc = { 1030 { 1031 .name = BLOCK_OPT_SIZE, 1032 .type = QEMU_OPT_SIZE, 1033 .help = "Virtual disk size" 1034 }, 1035 { 1036 .name = BLOCK_OPT_BACKING_FILE, 1037 .type = QEMU_OPT_STRING, 1038 .help = "File name of a base image" 1039 }, 1040 { 1041 .name = BLOCK_OPT_ENCRYPT, 1042 .type = QEMU_OPT_BOOL, 1043 .help = "Encrypt the image", 1044 .def_value_str = "off" 1045 }, 1046 { /* end of list */ } 1047 } 1048 }; 1049 1050 static BlockDriver bdrv_qcow = { 1051 .format_name = "qcow", 1052 .instance_size = sizeof(BDRVQcowState), 1053 .bdrv_probe = qcow_probe, 1054 .bdrv_open = qcow_open, 1055 .bdrv_close = qcow_close, 1056 .bdrv_child_perm = bdrv_format_default_perms, 1057 .bdrv_reopen_prepare = qcow_reopen_prepare, 1058 .bdrv_create = qcow_create, 1059 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1060 .supports_backing = true, 1061 1062 .bdrv_co_readv = qcow_co_readv, 1063 .bdrv_co_writev = qcow_co_writev, 1064 .bdrv_co_get_block_status = qcow_co_get_block_status, 1065 1066 .bdrv_set_key = qcow_set_key, 1067 .bdrv_make_empty = qcow_make_empty, 1068 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1069 .bdrv_get_info = qcow_get_info, 1070 1071 .create_opts = &qcow_create_opts, 1072 }; 1073 1074 static void bdrv_qcow_init(void) 1075 { 1076 bdrv_register(&bdrv_qcow); 1077 } 1078 1079 block_init(bdrv_qcow_init); 1080