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