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 error_setg(errp, "AES cipher not available"); 158 ret = -EINVAL; 159 goto fail; 160 } 161 s->crypt_method_header = header.crypt_method; 162 if (s->crypt_method_header) { 163 if (bdrv_uses_whitelist() && 164 s->crypt_method_header == QCOW_CRYPT_AES) { 165 error_setg(errp, 166 "Use of AES-CBC encrypted qcow images is no longer " 167 "supported in system emulators"); 168 error_append_hint(errp, 169 "You can use 'qemu-img convert' to convert your " 170 "image to an alternative supported format, such " 171 "as unencrypted qcow, or raw with the LUKS " 172 "format instead.\n"); 173 ret = -ENOSYS; 174 goto fail; 175 } 176 177 bs->encrypted = true; 178 } 179 s->cluster_bits = header.cluster_bits; 180 s->cluster_size = 1 << s->cluster_bits; 181 s->cluster_sectors = 1 << (s->cluster_bits - 9); 182 s->l2_bits = header.l2_bits; 183 s->l2_size = 1 << s->l2_bits; 184 bs->total_sectors = header.size / 512; 185 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 186 187 /* read the level 1 table */ 188 shift = s->cluster_bits + s->l2_bits; 189 if (header.size > UINT64_MAX - (1LL << shift)) { 190 error_setg(errp, "Image too large"); 191 ret = -EINVAL; 192 goto fail; 193 } else { 194 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 195 if (l1_size > INT_MAX / sizeof(uint64_t)) { 196 error_setg(errp, "Image too large"); 197 ret = -EINVAL; 198 goto fail; 199 } 200 s->l1_size = l1_size; 201 } 202 203 s->l1_table_offset = header.l1_table_offset; 204 s->l1_table = g_try_new(uint64_t, s->l1_size); 205 if (s->l1_table == NULL) { 206 error_setg(errp, "Could not allocate memory for L1 table"); 207 ret = -ENOMEM; 208 goto fail; 209 } 210 211 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 212 s->l1_size * sizeof(uint64_t)); 213 if (ret < 0) { 214 goto fail; 215 } 216 217 for(i = 0;i < s->l1_size; i++) { 218 be64_to_cpus(&s->l1_table[i]); 219 } 220 221 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 222 s->l2_cache = 223 qemu_try_blockalign(bs->file->bs, 224 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 225 if (s->l2_cache == NULL) { 226 error_setg(errp, "Could not allocate L2 table cache"); 227 ret = -ENOMEM; 228 goto fail; 229 } 230 s->cluster_cache = g_malloc(s->cluster_size); 231 s->cluster_data = g_malloc(s->cluster_size); 232 s->cluster_cache_offset = -1; 233 234 /* read the backing file name */ 235 if (header.backing_file_offset != 0) { 236 len = header.backing_file_size; 237 if (len > 1023 || len >= sizeof(bs->backing_file)) { 238 error_setg(errp, "Backing file name too long"); 239 ret = -EINVAL; 240 goto fail; 241 } 242 ret = bdrv_pread(bs->file, header.backing_file_offset, 243 bs->backing_file, len); 244 if (ret < 0) { 245 goto fail; 246 } 247 bs->backing_file[len] = '\0'; 248 } 249 250 /* Disable migration when qcow images are used */ 251 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 252 "does not support live migration", 253 bdrv_get_device_or_node_name(bs)); 254 migrate_add_blocker(s->migration_blocker); 255 256 qemu_co_mutex_init(&s->lock); 257 return 0; 258 259 fail: 260 g_free(s->l1_table); 261 qemu_vfree(s->l2_cache); 262 g_free(s->cluster_cache); 263 g_free(s->cluster_data); 264 return ret; 265 } 266 267 268 /* We have nothing to do for QCOW reopen, stubs just return 269 * success */ 270 static int qcow_reopen_prepare(BDRVReopenState *state, 271 BlockReopenQueue *queue, Error **errp) 272 { 273 return 0; 274 } 275 276 static int qcow_set_key(BlockDriverState *bs, const char *key) 277 { 278 BDRVQcowState *s = bs->opaque; 279 uint8_t keybuf[16]; 280 int len, i; 281 Error *err; 282 283 memset(keybuf, 0, 16); 284 len = strlen(key); 285 if (len > 16) 286 len = 16; 287 /* XXX: we could compress the chars to 7 bits to increase 288 entropy */ 289 for(i = 0;i < len;i++) { 290 keybuf[i] = key[i]; 291 } 292 assert(bs->encrypted); 293 294 qcrypto_cipher_free(s->cipher); 295 s->cipher = qcrypto_cipher_new( 296 QCRYPTO_CIPHER_ALG_AES_128, 297 QCRYPTO_CIPHER_MODE_CBC, 298 keybuf, G_N_ELEMENTS(keybuf), 299 &err); 300 301 if (!s->cipher) { 302 /* XXX would be nice if errors in this method could 303 * be properly propagate to the caller. Would need 304 * the bdrv_set_key() API signature to be fixed. */ 305 error_free(err); 306 return -1; 307 } 308 return 0; 309 } 310 311 /* The crypt function is compatible with the linux cryptoloop 312 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 313 supported */ 314 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 315 uint8_t *out_buf, const uint8_t *in_buf, 316 int nb_sectors, bool enc, Error **errp) 317 { 318 union { 319 uint64_t ll[2]; 320 uint8_t b[16]; 321 } ivec; 322 int i; 323 int ret; 324 325 for(i = 0; i < nb_sectors; i++) { 326 ivec.ll[0] = cpu_to_le64(sector_num); 327 ivec.ll[1] = 0; 328 if (qcrypto_cipher_setiv(s->cipher, 329 ivec.b, G_N_ELEMENTS(ivec.b), 330 errp) < 0) { 331 return -1; 332 } 333 if (enc) { 334 ret = qcrypto_cipher_encrypt(s->cipher, 335 in_buf, 336 out_buf, 337 512, 338 errp); 339 } else { 340 ret = qcrypto_cipher_decrypt(s->cipher, 341 in_buf, 342 out_buf, 343 512, 344 errp); 345 } 346 if (ret < 0) { 347 return -1; 348 } 349 sector_num++; 350 in_buf += 512; 351 out_buf += 512; 352 } 353 return 0; 354 } 355 356 /* 'allocate' is: 357 * 358 * 0 to not allocate. 359 * 360 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 361 * 'n_end') 362 * 363 * 2 to allocate a compressed cluster of size 364 * 'compressed_size'. 'compressed_size' must be > 0 and < 365 * cluster_size 366 * 367 * return 0 if not allocated. 368 */ 369 static uint64_t get_cluster_offset(BlockDriverState *bs, 370 uint64_t offset, int allocate, 371 int compressed_size, 372 int n_start, int n_end) 373 { 374 BDRVQcowState *s = bs->opaque; 375 int min_index, i, j, l1_index, l2_index; 376 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 377 uint32_t min_count; 378 int new_l2_table; 379 380 l1_index = offset >> (s->l2_bits + s->cluster_bits); 381 l2_offset = s->l1_table[l1_index]; 382 new_l2_table = 0; 383 if (!l2_offset) { 384 if (!allocate) 385 return 0; 386 /* allocate a new l2 entry */ 387 l2_offset = bdrv_getlength(bs->file->bs); 388 /* round to cluster size */ 389 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 390 /* update the L1 entry */ 391 s->l1_table[l1_index] = l2_offset; 392 tmp = cpu_to_be64(l2_offset); 393 if (bdrv_pwrite_sync(bs->file, 394 s->l1_table_offset + l1_index * sizeof(tmp), 395 &tmp, sizeof(tmp)) < 0) 396 return 0; 397 new_l2_table = 1; 398 } 399 for(i = 0; i < L2_CACHE_SIZE; i++) { 400 if (l2_offset == s->l2_cache_offsets[i]) { 401 /* increment the hit count */ 402 if (++s->l2_cache_counts[i] == 0xffffffff) { 403 for(j = 0; j < L2_CACHE_SIZE; j++) { 404 s->l2_cache_counts[j] >>= 1; 405 } 406 } 407 l2_table = s->l2_cache + (i << s->l2_bits); 408 goto found; 409 } 410 } 411 /* not found: load a new entry in the least used one */ 412 min_index = 0; 413 min_count = 0xffffffff; 414 for(i = 0; i < L2_CACHE_SIZE; i++) { 415 if (s->l2_cache_counts[i] < min_count) { 416 min_count = s->l2_cache_counts[i]; 417 min_index = i; 418 } 419 } 420 l2_table = s->l2_cache + (min_index << s->l2_bits); 421 if (new_l2_table) { 422 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 423 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 424 s->l2_size * sizeof(uint64_t)) < 0) 425 return 0; 426 } else { 427 if (bdrv_pread(bs->file, l2_offset, l2_table, 428 s->l2_size * sizeof(uint64_t)) != 429 s->l2_size * sizeof(uint64_t)) 430 return 0; 431 } 432 s->l2_cache_offsets[min_index] = l2_offset; 433 s->l2_cache_counts[min_index] = 1; 434 found: 435 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 436 cluster_offset = be64_to_cpu(l2_table[l2_index]); 437 if (!cluster_offset || 438 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 439 if (!allocate) 440 return 0; 441 /* allocate a new cluster */ 442 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 443 (n_end - n_start) < s->cluster_sectors) { 444 /* if the cluster is already compressed, we must 445 decompress it in the case it is not completely 446 overwritten */ 447 if (decompress_cluster(bs, cluster_offset) < 0) 448 return 0; 449 cluster_offset = bdrv_getlength(bs->file->bs); 450 cluster_offset = (cluster_offset + s->cluster_size - 1) & 451 ~(s->cluster_size - 1); 452 /* write the cluster content */ 453 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 454 s->cluster_size) != 455 s->cluster_size) 456 return -1; 457 } else { 458 cluster_offset = bdrv_getlength(bs->file->bs); 459 if (allocate == 1) { 460 /* round to cluster size */ 461 cluster_offset = (cluster_offset + s->cluster_size - 1) & 462 ~(s->cluster_size - 1); 463 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size); 464 /* if encrypted, we must initialize the cluster 465 content which won't be written */ 466 if (bs->encrypted && 467 (n_end - n_start) < s->cluster_sectors) { 468 uint64_t start_sect; 469 assert(s->cipher); 470 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 471 memset(s->cluster_data + 512, 0x00, 512); 472 for(i = 0; i < s->cluster_sectors; i++) { 473 if (i < n_start || i >= n_end) { 474 Error *err = NULL; 475 if (encrypt_sectors(s, start_sect + i, 476 s->cluster_data, 477 s->cluster_data + 512, 1, 478 true, &err) < 0) { 479 error_free(err); 480 errno = EIO; 481 return -1; 482 } 483 if (bdrv_pwrite(bs->file, 484 cluster_offset + i * 512, 485 s->cluster_data, 512) != 512) 486 return -1; 487 } 488 } 489 } 490 } else if (allocate == 2) { 491 cluster_offset |= QCOW_OFLAG_COMPRESSED | 492 (uint64_t)compressed_size << (63 - s->cluster_bits); 493 } 494 } 495 /* update L2 table */ 496 tmp = cpu_to_be64(cluster_offset); 497 l2_table[l2_index] = tmp; 498 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 499 &tmp, sizeof(tmp)) < 0) 500 return 0; 501 } 502 return cluster_offset; 503 } 504 505 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 506 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 507 { 508 BDRVQcowState *s = bs->opaque; 509 int index_in_cluster, n; 510 uint64_t cluster_offset; 511 512 qemu_co_mutex_lock(&s->lock); 513 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 514 qemu_co_mutex_unlock(&s->lock); 515 index_in_cluster = sector_num & (s->cluster_sectors - 1); 516 n = s->cluster_sectors - index_in_cluster; 517 if (n > nb_sectors) 518 n = nb_sectors; 519 *pnum = n; 520 if (!cluster_offset) { 521 return 0; 522 } 523 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 524 return BDRV_BLOCK_DATA; 525 } 526 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 527 *file = bs->file->bs; 528 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 529 } 530 531 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 532 const uint8_t *buf, int buf_size) 533 { 534 z_stream strm1, *strm = &strm1; 535 int ret, out_len; 536 537 memset(strm, 0, sizeof(*strm)); 538 539 strm->next_in = (uint8_t *)buf; 540 strm->avail_in = buf_size; 541 strm->next_out = out_buf; 542 strm->avail_out = out_buf_size; 543 544 ret = inflateInit2(strm, -12); 545 if (ret != Z_OK) 546 return -1; 547 ret = inflate(strm, Z_FINISH); 548 out_len = strm->next_out - out_buf; 549 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 550 out_len != out_buf_size) { 551 inflateEnd(strm); 552 return -1; 553 } 554 inflateEnd(strm); 555 return 0; 556 } 557 558 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 559 { 560 BDRVQcowState *s = bs->opaque; 561 int ret, csize; 562 uint64_t coffset; 563 564 coffset = cluster_offset & s->cluster_offset_mask; 565 if (s->cluster_cache_offset != coffset) { 566 csize = cluster_offset >> (63 - s->cluster_bits); 567 csize &= (s->cluster_size - 1); 568 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 569 if (ret != csize) 570 return -1; 571 if (decompress_buffer(s->cluster_cache, s->cluster_size, 572 s->cluster_data, csize) < 0) { 573 return -1; 574 } 575 s->cluster_cache_offset = coffset; 576 } 577 return 0; 578 } 579 580 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 581 int nb_sectors, QEMUIOVector *qiov) 582 { 583 BDRVQcowState *s = bs->opaque; 584 int index_in_cluster; 585 int ret = 0, n; 586 uint64_t cluster_offset; 587 struct iovec hd_iov; 588 QEMUIOVector hd_qiov; 589 uint8_t *buf; 590 void *orig_buf; 591 Error *err = NULL; 592 593 if (qiov->niov > 1) { 594 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 595 if (buf == NULL) { 596 return -ENOMEM; 597 } 598 } else { 599 orig_buf = NULL; 600 buf = (uint8_t *)qiov->iov->iov_base; 601 } 602 603 qemu_co_mutex_lock(&s->lock); 604 605 while (nb_sectors != 0) { 606 /* prepare next request */ 607 cluster_offset = get_cluster_offset(bs, sector_num << 9, 608 0, 0, 0, 0); 609 index_in_cluster = sector_num & (s->cluster_sectors - 1); 610 n = s->cluster_sectors - index_in_cluster; 611 if (n > nb_sectors) { 612 n = nb_sectors; 613 } 614 615 if (!cluster_offset) { 616 if (bs->backing) { 617 /* read from the base image */ 618 hd_iov.iov_base = (void *)buf; 619 hd_iov.iov_len = n * 512; 620 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 621 qemu_co_mutex_unlock(&s->lock); 622 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov); 623 qemu_co_mutex_lock(&s->lock); 624 if (ret < 0) { 625 goto fail; 626 } 627 } else { 628 /* Note: in this case, no need to wait */ 629 memset(buf, 0, 512 * n); 630 } 631 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 632 /* add AIO support for compressed blocks ? */ 633 if (decompress_cluster(bs, cluster_offset) < 0) { 634 goto fail; 635 } 636 memcpy(buf, 637 s->cluster_cache + index_in_cluster * 512, 512 * n); 638 } else { 639 if ((cluster_offset & 511) != 0) { 640 goto fail; 641 } 642 hd_iov.iov_base = (void *)buf; 643 hd_iov.iov_len = n * 512; 644 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 645 qemu_co_mutex_unlock(&s->lock); 646 ret = bdrv_co_readv(bs->file, 647 (cluster_offset >> 9) + index_in_cluster, 648 n, &hd_qiov); 649 qemu_co_mutex_lock(&s->lock); 650 if (ret < 0) { 651 break; 652 } 653 if (bs->encrypted) { 654 assert(s->cipher); 655 if (encrypt_sectors(s, sector_num, buf, buf, 656 n, false, &err) < 0) { 657 goto fail; 658 } 659 } 660 } 661 ret = 0; 662 663 nb_sectors -= n; 664 sector_num += n; 665 buf += n * 512; 666 } 667 668 done: 669 qemu_co_mutex_unlock(&s->lock); 670 671 if (qiov->niov > 1) { 672 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 673 qemu_vfree(orig_buf); 674 } 675 676 return ret; 677 678 fail: 679 error_free(err); 680 ret = -EIO; 681 goto done; 682 } 683 684 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 685 int nb_sectors, QEMUIOVector *qiov) 686 { 687 BDRVQcowState *s = bs->opaque; 688 int index_in_cluster; 689 uint64_t cluster_offset; 690 const uint8_t *src_buf; 691 int ret = 0, n; 692 uint8_t *cluster_data = NULL; 693 struct iovec hd_iov; 694 QEMUIOVector hd_qiov; 695 uint8_t *buf; 696 void *orig_buf; 697 698 s->cluster_cache_offset = -1; /* disable compressed cache */ 699 700 if (qiov->niov > 1) { 701 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 702 if (buf == NULL) { 703 return -ENOMEM; 704 } 705 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 706 } else { 707 orig_buf = NULL; 708 buf = (uint8_t *)qiov->iov->iov_base; 709 } 710 711 qemu_co_mutex_lock(&s->lock); 712 713 while (nb_sectors != 0) { 714 715 index_in_cluster = sector_num & (s->cluster_sectors - 1); 716 n = s->cluster_sectors - index_in_cluster; 717 if (n > nb_sectors) { 718 n = nb_sectors; 719 } 720 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 721 index_in_cluster, 722 index_in_cluster + n); 723 if (!cluster_offset || (cluster_offset & 511) != 0) { 724 ret = -EIO; 725 break; 726 } 727 if (bs->encrypted) { 728 Error *err = NULL; 729 assert(s->cipher); 730 if (!cluster_data) { 731 cluster_data = g_malloc0(s->cluster_size); 732 } 733 if (encrypt_sectors(s, sector_num, cluster_data, buf, 734 n, true, &err) < 0) { 735 error_free(err); 736 ret = -EIO; 737 break; 738 } 739 src_buf = cluster_data; 740 } else { 741 src_buf = buf; 742 } 743 744 hd_iov.iov_base = (void *)src_buf; 745 hd_iov.iov_len = n * 512; 746 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 747 qemu_co_mutex_unlock(&s->lock); 748 ret = bdrv_co_writev(bs->file, 749 (cluster_offset >> 9) + index_in_cluster, 750 n, &hd_qiov); 751 qemu_co_mutex_lock(&s->lock); 752 if (ret < 0) { 753 break; 754 } 755 ret = 0; 756 757 nb_sectors -= n; 758 sector_num += n; 759 buf += n * 512; 760 } 761 qemu_co_mutex_unlock(&s->lock); 762 763 if (qiov->niov > 1) { 764 qemu_vfree(orig_buf); 765 } 766 g_free(cluster_data); 767 768 return ret; 769 } 770 771 static void qcow_close(BlockDriverState *bs) 772 { 773 BDRVQcowState *s = bs->opaque; 774 775 qcrypto_cipher_free(s->cipher); 776 s->cipher = NULL; 777 g_free(s->l1_table); 778 qemu_vfree(s->l2_cache); 779 g_free(s->cluster_cache); 780 g_free(s->cluster_data); 781 782 migrate_del_blocker(s->migration_blocker); 783 error_free(s->migration_blocker); 784 } 785 786 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 787 { 788 int header_size, backing_filename_len, l1_size, shift, i; 789 QCowHeader header; 790 uint8_t *tmp; 791 int64_t total_size = 0; 792 char *backing_file = NULL; 793 int flags = 0; 794 Error *local_err = NULL; 795 int ret; 796 BlockBackend *qcow_blk; 797 798 /* Read out options */ 799 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 800 BDRV_SECTOR_SIZE); 801 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 802 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 803 flags |= BLOCK_FLAG_ENCRYPT; 804 } 805 806 ret = bdrv_create_file(filename, opts, &local_err); 807 if (ret < 0) { 808 error_propagate(errp, local_err); 809 goto cleanup; 810 } 811 812 qcow_blk = blk_new_open(filename, NULL, NULL, 813 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); 814 if (qcow_blk == NULL) { 815 error_propagate(errp, local_err); 816 ret = -EIO; 817 goto cleanup; 818 } 819 820 blk_set_allow_write_beyond_eof(qcow_blk, true); 821 822 ret = blk_truncate(qcow_blk, 0); 823 if (ret < 0) { 824 goto exit; 825 } 826 827 memset(&header, 0, sizeof(header)); 828 header.magic = cpu_to_be32(QCOW_MAGIC); 829 header.version = cpu_to_be32(QCOW_VERSION); 830 header.size = cpu_to_be64(total_size); 831 header_size = sizeof(header); 832 backing_filename_len = 0; 833 if (backing_file) { 834 if (strcmp(backing_file, "fat:")) { 835 header.backing_file_offset = cpu_to_be64(header_size); 836 backing_filename_len = strlen(backing_file); 837 header.backing_file_size = cpu_to_be32(backing_filename_len); 838 header_size += backing_filename_len; 839 } else { 840 /* special backing file for vvfat */ 841 backing_file = NULL; 842 } 843 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 844 unmodified sectors */ 845 header.l2_bits = 12; /* 32 KB L2 tables */ 846 } else { 847 header.cluster_bits = 12; /* 4 KB clusters */ 848 header.l2_bits = 9; /* 4 KB L2 tables */ 849 } 850 header_size = (header_size + 7) & ~7; 851 shift = header.cluster_bits + header.l2_bits; 852 l1_size = (total_size + (1LL << shift) - 1) >> shift; 853 854 header.l1_table_offset = cpu_to_be64(header_size); 855 if (flags & BLOCK_FLAG_ENCRYPT) { 856 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 857 } else { 858 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 859 } 860 861 /* write all the data */ 862 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 863 if (ret != sizeof(header)) { 864 goto exit; 865 } 866 867 if (backing_file) { 868 ret = blk_pwrite(qcow_blk, sizeof(header), 869 backing_file, backing_filename_len, 0); 870 if (ret != backing_filename_len) { 871 goto exit; 872 } 873 } 874 875 tmp = g_malloc0(BDRV_SECTOR_SIZE); 876 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 877 i++) { 878 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 879 tmp, BDRV_SECTOR_SIZE, 0); 880 if (ret != BDRV_SECTOR_SIZE) { 881 g_free(tmp); 882 goto exit; 883 } 884 } 885 886 g_free(tmp); 887 ret = 0; 888 exit: 889 blk_unref(qcow_blk); 890 cleanup: 891 g_free(backing_file); 892 return ret; 893 } 894 895 static int qcow_make_empty(BlockDriverState *bs) 896 { 897 BDRVQcowState *s = bs->opaque; 898 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 899 int ret; 900 901 memset(s->l1_table, 0, l1_length); 902 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 903 l1_length) < 0) 904 return -1; 905 ret = bdrv_truncate(bs->file->bs, s->l1_table_offset + l1_length); 906 if (ret < 0) 907 return ret; 908 909 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 910 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 911 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 912 913 return 0; 914 } 915 916 typedef struct QcowWriteCo { 917 BlockDriverState *bs; 918 int64_t sector_num; 919 const uint8_t *buf; 920 int nb_sectors; 921 int ret; 922 } QcowWriteCo; 923 924 static void qcow_write_co_entry(void *opaque) 925 { 926 QcowWriteCo *co = opaque; 927 QEMUIOVector qiov; 928 929 struct iovec iov = (struct iovec) { 930 .iov_base = (uint8_t*) co->buf, 931 .iov_len = co->nb_sectors * BDRV_SECTOR_SIZE, 932 }; 933 qemu_iovec_init_external(&qiov, &iov, 1); 934 935 co->ret = qcow_co_writev(co->bs, co->sector_num, co->nb_sectors, &qiov); 936 } 937 938 /* Wrapper for non-coroutine contexts */ 939 static int qcow_write(BlockDriverState *bs, int64_t sector_num, 940 const uint8_t *buf, int nb_sectors) 941 { 942 Coroutine *co; 943 AioContext *aio_context = bdrv_get_aio_context(bs); 944 QcowWriteCo data = { 945 .bs = bs, 946 .sector_num = sector_num, 947 .buf = buf, 948 .nb_sectors = nb_sectors, 949 .ret = -EINPROGRESS, 950 }; 951 co = qemu_coroutine_create(qcow_write_co_entry); 952 qemu_coroutine_enter(co, &data); 953 while (data.ret == -EINPROGRESS) { 954 aio_poll(aio_context, true); 955 } 956 return data.ret; 957 } 958 959 /* XXX: put compressed sectors first, then all the cluster aligned 960 tables to avoid losing bytes in alignment */ 961 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 962 const uint8_t *buf, int nb_sectors) 963 { 964 BDRVQcowState *s = bs->opaque; 965 z_stream strm; 966 int ret, out_len; 967 uint8_t *out_buf; 968 uint64_t cluster_offset; 969 970 if (nb_sectors != s->cluster_sectors) { 971 ret = -EINVAL; 972 973 /* Zero-pad last write if image size is not cluster aligned */ 974 if (sector_num + nb_sectors == bs->total_sectors && 975 nb_sectors < s->cluster_sectors) { 976 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 977 memset(pad_buf, 0, s->cluster_size); 978 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 979 ret = qcow_write_compressed(bs, sector_num, 980 pad_buf, s->cluster_sectors); 981 qemu_vfree(pad_buf); 982 } 983 return ret; 984 } 985 986 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 987 988 /* best compression, small window, no zlib header */ 989 memset(&strm, 0, sizeof(strm)); 990 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 991 Z_DEFLATED, -12, 992 9, Z_DEFAULT_STRATEGY); 993 if (ret != 0) { 994 ret = -EINVAL; 995 goto fail; 996 } 997 998 strm.avail_in = s->cluster_size; 999 strm.next_in = (uint8_t *)buf; 1000 strm.avail_out = s->cluster_size; 1001 strm.next_out = out_buf; 1002 1003 ret = deflate(&strm, Z_FINISH); 1004 if (ret != Z_STREAM_END && ret != Z_OK) { 1005 deflateEnd(&strm); 1006 ret = -EINVAL; 1007 goto fail; 1008 } 1009 out_len = strm.next_out - out_buf; 1010 1011 deflateEnd(&strm); 1012 1013 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1014 /* could not compress: write normal cluster */ 1015 ret = qcow_write(bs, sector_num, buf, s->cluster_sectors); 1016 if (ret < 0) { 1017 goto fail; 1018 } 1019 } else { 1020 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 1021 out_len, 0, 0); 1022 if (cluster_offset == 0) { 1023 ret = -EIO; 1024 goto fail; 1025 } 1026 1027 cluster_offset &= s->cluster_offset_mask; 1028 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 1029 if (ret < 0) { 1030 goto fail; 1031 } 1032 } 1033 1034 ret = 0; 1035 fail: 1036 g_free(out_buf); 1037 return ret; 1038 } 1039 1040 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1041 { 1042 BDRVQcowState *s = bs->opaque; 1043 bdi->cluster_size = s->cluster_size; 1044 return 0; 1045 } 1046 1047 static QemuOptsList qcow_create_opts = { 1048 .name = "qcow-create-opts", 1049 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1050 .desc = { 1051 { 1052 .name = BLOCK_OPT_SIZE, 1053 .type = QEMU_OPT_SIZE, 1054 .help = "Virtual disk size" 1055 }, 1056 { 1057 .name = BLOCK_OPT_BACKING_FILE, 1058 .type = QEMU_OPT_STRING, 1059 .help = "File name of a base image" 1060 }, 1061 { 1062 .name = BLOCK_OPT_ENCRYPT, 1063 .type = QEMU_OPT_BOOL, 1064 .help = "Encrypt the image", 1065 .def_value_str = "off" 1066 }, 1067 { /* end of list */ } 1068 } 1069 }; 1070 1071 static BlockDriver bdrv_qcow = { 1072 .format_name = "qcow", 1073 .instance_size = sizeof(BDRVQcowState), 1074 .bdrv_probe = qcow_probe, 1075 .bdrv_open = qcow_open, 1076 .bdrv_close = qcow_close, 1077 .bdrv_reopen_prepare = qcow_reopen_prepare, 1078 .bdrv_create = qcow_create, 1079 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1080 .supports_backing = true, 1081 1082 .bdrv_co_readv = qcow_co_readv, 1083 .bdrv_co_writev = qcow_co_writev, 1084 .bdrv_co_get_block_status = qcow_co_get_block_status, 1085 1086 .bdrv_set_key = qcow_set_key, 1087 .bdrv_make_empty = qcow_make_empty, 1088 .bdrv_write_compressed = qcow_write_compressed, 1089 .bdrv_get_info = qcow_get_info, 1090 1091 .create_opts = &qcow_create_opts, 1092 }; 1093 1094 static void bdrv_qcow_init(void) 1095 { 1096 bdrv_register(&bdrv_qcow); 1097 } 1098 1099 block_init(bdrv_qcow_init); 1100